SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I
Edition: Model Aviation - 1988/09
Page Numbers: 85, 86, 87, 88, 91, 92, 169, 172, 173
SINCE MY PREVIOUS article Free Flight Mini-Electrics October 1987 sue magazine much has happened fast-growing little corner modeling First response article much greater expected Apparently out anxious learn about get started Mini-Elec trics Ill attempt answer some questions provide additional incentives give type flight whirl Based questions Ive received some field experience gained over last flying season article will touch follow ing items 1 New Mini-Electric products 2 Building good charger 3 Ways get power 4 Multimotors Whats new new Mini-Electric motor system availablenew least US fliers power unit Knight Prid ham Engineering Ltd England offers several unique useful features Called KPO1 basic system employs same Mabuchi motor VL MRC FE systems described last article Well-known British Scale modeler Derek Knight individual behind KPO1 system Derek has won number nation al-level Free Flight Scale championships several beautiful aircraft powered Mini-Electric motor system KPOl system uses three 50 mAh re Top Lightweight structures finishes important Electric model authors 42-in-span Do-X weighs incredibly light 19 oz due construction mostly 1A2 balsa tissueldope finish Left Don first conceived idea Free Flight ver sion Dornier Do-X flying boat knew would acid test multi-engine mini-electrics would work Right Consistent awe-inspiring flights over 1 mm laid rest ail doubts big model sails along smartly landings grass smooth scaleilke September 1988 85 chargeable cells gear ratio 4251 451 ratio used Ferrell Enmotor prop shaft slightly less terprise MRC units well below 71 ratio employed VL Mini-Electric system also incorpo SERIESWIRING MOTORS Switch Charging Plug PARALLEL prefered ~Li Cells 70 mAh WIRING MULTIPLE MOTORS Parallel liii Three cells 270 mAh 300 mAh increase individual cell [jJJ pacty 70-100 mAh additional motor used Opposite Pairs Parallel Only Numbers Motors Three cells 150 270 mAh motor pair 86 Model Aviation Left Each nacelle has HiLine mujur iuming two 4-in-aiameier props tanoem otal ot six motors ana 12 propsi 111gm ne tront hatch removed charging ne pocket field charger swItch charge plug controls Opposing pair engine nacelles 3 Cells 150 mAh rates clever elegantly simple on-off switcha set brass contact points mounted motor frame opened cam propeller shaft prop pushed rear points opened motor shut off prop forward flying position points closed charge flight battery prop pushed rear shut off motor battery cells activated through charging socket wired three cells flier ready launch model simply pulls prop forward motor turned Actually found could simply flip prop overlike starting CO2 motorfor easy instant -I0 starts model strikes object less head-on theory prop will pushed rear shutting down mo tor practice however saving mech anism doesnt invariably work Included KPOl system two pro pellers manufactured K&P Ltd pro pellers about 5 /2 diameter made stiff fiberglass-filled plastic three-cell battery comes encased plastic MINI ELECTRIC FIELD CHARGER SYSTEM 00 0 0 I 40 2 3 cells /\ j/ Parts List RADIO SHACK Catog Nos 1 Four C Cells series 23-141ea $495 2 DPDT Mini-Toggle Center Off 275-620$249 3 1 Ohm 10 Watt Resistor 271-1312/89 4 Optional Lo Indicator 15V Mini-Lamp 272-113989 5 Power Jack Socket 274-15652199 6 Sub-Mini Phone Plug 274-2892/Si 39 7 6V DC l5OmA Wall Charger 273-1454$695 8 Sub-Mini Jack Airplane 274-2922/si 69 9 Micro-Mini SPDT On-Off Switch 275-625$199 10 Timer monitor charge time 63-840$399 September 1988 87 Dons Curtlas spans 26 weighs 41/a oz Tue same custom-wouna 1uu mAn three-cell motor HiLine has powered model over 150 successful 1-mm hts Isis and.rlstructlons pro vided HiLines ldt rewind assemble two mini-electric motors simple economIcal way try out twIn Electrics flU .ruu mmnI-wwIrI Iuuiui urni uu usi5 tomlzea fit particular model Rewind ing motor painful sounds Left VL Products new mini-motor can powered two- three-cell flight packs 71 gear ratio allows use larger props Right Ganging two motors single shaft simple way get power Two HiLine motors used produce 15-watt package COMPONENT PLACEMENT ON TOP PLATE 1-n-j% loW / Th battery 14charge socket Bottom View 0 HI LO lamp switch View tube integral part power unit can however removed placed elsewhere model ex tension wire provided Total weight KPOl system about 31 grams addition two props extra pinion gear provided Charging three flight cells accomplished through sub-mini-jack identical found Radio Shack stores discussed later charger provided matching charging plug attach charger included recommended charging current ampere maxi mum three minutes KPO1 system recommended models up 120 grams total weight wingspans up 30 its three cells lower gear ratio KPOl noticeably powerful similar units run two cells later current drawn somewhat higher alsoover 2 amps compared 2 amps drawn conventional system sum very well-engineered well-built system KPOl sells 19Q5 British pounds sterling little over $36 recent exchange rates Write Knight Pridham Eng Ltd Castle Road Rowlands Castle Hants P09 6AS England order squeeze some test flying before snow weather precluded put KPOl 18-in-span Grum man Wildcat designed Earl Stahl wing area 62 sq however model bit small side far ideal test bed All-up weight came 60 grams yielded wing loading about 5 oz per sq fton high side Mini-Electrics However after few trim flights add ing about 20 additional right thrust tal 30 plus bit clay tail ballast little Wildcat flew very well indeed con sistently turned realistic flights 30 45 seconds charges approximately two minutes VL Products have made improvement mini-electric motors Both HY 70B model has flight battery atContinued page 91 88 Model Aviation neat Knight Pridham mini-electric unit latest commercial system available features clever on-off safety switch built onto prop shaft Text has details address tached motor frame HY 7OBR model uses remote battery separated motor now have plastic propeller shaft reinforced brass sleeve greatly strengthens shaft connects spur gear prop VL mini-electric motors still use what believe very desirable feature such systemsan automatic freewheel ing propeller disengages motor prop shaft power ex hausted helps models glide also reduces probability battery being damaged windmilling prop driving motor addition free wheeling propeller ensures disengagement prop motor event crash landing shortly after launch thereby saving battery motor overheating possible damage VL now also offers three different flight batteries standard two 50 mAh cells pack two 80 mAh cells longer runs containing three 50 mAh cells shorter zippier runs HY-70B system particularly well suited short-nosed sport models such little Strato Streak shown accompanying photos Because high 71 gear ratio consequent ability turn rather large props VL motors also ideal short-nosed high-drag Scale model such World War biplanes Still available Model Rectifier Cor poration reported last year re placement motor system little readyto-fly foamie airplane However Ive learned heavy demand replace ment motors following article severely taxed manufacturers supply spares According understanding current MRC policy sell up two mo tors per customer new price $1650still good bargain Write Model Rectifier Corporation 2500 Woodbridge Ave Edison NJ 08817 attention Customer Service details Charging up newcomer Mini Electrics going have problem likely will arise charging flight bat tery Short motor runs weak perform ance otherwise good model can often attributed inadequate charging equip ment and/or poor charging technique Most mini-electric motor systems come chargers although some provide charger/battery box three four Csize dry cells systems provide some minimal charging instructions questions left unanswered dry cell chargers OK occasional use short-lived expensive undependable fly very much Some frequently asked questions about charging can sure re peatable consistent adequate charges Can charge both two- three-cell flight bat teries same charger about Left source small 70 -i-Cd cells 9-volt rechargeable battery available Haalo anack ana vereaay aissecisa DaT tery such will provide sIx medium-quality cells Right Various capacity flight packs can made up NI-Cd cells available heavier higher capacity cells often worth extra weight penalty because provide longer running times September 1988 91 FIELD CHARGER ASSEMBLY SWITCH FOR CHARGING 2 CELLS LO LLS HI OR OFF 1/16PLY TOP GLUE TO SPACERS LO PILOTLAMP CHARGE SOCKET BALSA BLOCK S PA C E R S SHRINK WRAP COVER ATTACHTIMER TO COVER cells different capacity What conven ient way keep track charge time really good charger should include instruc tion answer questions VL Products makes very good highly recommended charger described previous article transportable modelers field box Model FC 401 Powered 12-volt gel-cell car battery charger has ammeter means adjusting charge current auto shutoff timer serious Electric flier should own chargers However product will good job charging Mini-Electric system smaller hand-held charger can much convenient potentially less costly occasional flier someone just getting Mini-Electrics good pocket-sized charger would seem answer fliers Since available commercially designed objectives 1 Small portable 2 Capacity least 20 30 nonfad ing charges 3 Ability charge two three cells 50- to 270-mAh capacity 4 Rechargeable 5 Incorporate timer visually monitor charge time 6 Easy build readily available components charger designed meet re quirements shown accompanying di agrams will last indefinitely takes hassle out field charging parts available Radio Shack total about $35 have reasonable skills soldering iron give try heart charger ex pensive item set four C-size nickel cadmium Ni-Cd cells Dont skimp Real C cells have capacity 18 ampere hours will provide good solid charges full days flying Although may little less expensive bit lighter smaller capacity cells recom mended larger D-size cells would pro vide double capacity 40 ampere hours four cells com bined get quite heavy little awkward carry around dont mind extra weight however make satisfactory substitute use lower cost budget Ni-Cd cells such sold Radio Shack others spurious C D cells real ity much lower capacity cells exter nal can wrapped around bring up C D physical dimensions wall plug-in 6V adapter shown will fully activate field charger about 12 hours rate about 180 milliamps Once fully charged field charger can usually topped off three four hours after days use soldering charger components together during assembly very careful keep polarity shown Also make sure wires clear other eliminate possibility shorts convenient first assemble sol der components switch plug resistor indicator lamp charge cord 1/16 ply top plate Next glue balsa spacers bottom ply top 3A-in-tall spacers assure components top plate come contact tops cells also provide gluing surface attaching cells plate After double-checking connections sol der battery connections glue top plate battery together Thick cyanoacry late CyA glue makes quick job Test unit make sure everything functioning satisfactorily piece 2in-dia shrink tubing can shrunk around cells overlap top plate make nice neat package wrapping electri cal tape acceptable substitute shrink tube Finally clock/timer stuck outside case selfadhesive tape provided Charge unit eight 10 hours its ready go Sub-mini charging sockets will have added models use submini phone jack illustrated charger have found very neat effective charging hookup method have standardized its use models Knight Purdham KPO1 commercial motor system uses Re member match polarity plugs sockets field charger very easy use Turn both motor switch airplane field charger switch off posi tion thats center position charger switch Plug charger model set interval timer zero youre charging two cells turn charger switch LO start timer small indicator lamp should light confirming charging through 1-ohm resis tor charge three cells turn charger HI position turn timer charge rate will between 1 /2 2 am peres finished charging first turn charger switch off position pull out charger jack model fact always turn charger switch off whenever inserting drawing charger jack disad vantage sub-mini plugs jacks tendency momentarily short out jack inserted withdrawn cen ter off position switch prevents occurring field charger ever because tendency would recommend using sub-mini plugs jacks anything larger mini-electric three-cell motor four-cell charger have built about 10 chargers local flying buddies work ex tremely well No excuses bad chargeContinued page 169 92 Model Aviation Dave Reese built exciting Northrop flying wing Power four HiLine motors turning Cox three-blade props Two props turn right two left cancel out torque Small Old-Timer Free Flight models make terrific minI-electric models great flying iiuu 28-in Strato Streak powered motor VL Products three-cell battery pack TWINS ARE CLASSIC AND AFFORDABLE Looking inexpensive opposed twin replace shaking smelly gas burner want scale like appearance smooth running 2 cycle glow operation Yes its back basics EHS Tradings Twin Star Comments .Have lot engiwe no doubt ably best. Bd Thomas Lake Havasu AZ .The Twin Star ism esceptionaly smooth engne thu displacement size. Clarance Lee ENGINE EDITOR RCM MAGAZINE answer question often ked- muffler available Yes muffler & header available CALL FOR INFORMAllON EHS TRADING LTD 400 HUALANI ST BLDG 13E HILO HAWAII %720 1 -800-63HOBBV 808 935-9009 HA WAIl STD TIME 10 AM7PM Mon-S 00 Without Muffler ging plane down walking larger circle adds unneeded tenths second time Charging GloBee Fire Plug have sev eral requests concerning proper charging time battery system find gel cell bat tesy included unit should charged min imum overnight 15 hours prior contest use always carry additional freshly charged battery practice morning various events can insert freshly charged cell afternoons performance have seen competitors using battery day long adverse problems just worth taking chance Unfortunately gel cell batteries start run down will hold full charge few seconds battery will drop off glow plug second two will diminished engine starts first flip okay however have keep battery connected length time reduced amperage will result hard starting engine Also thought might mention use piece styrofoam stuck over battery posts held place healthy wrap electrical tape around battery assures bat tery contacts short out touching piece metal oould potential fire hazard occurred have also seen rheostat GloBec bat tery turned up too high Rat Scale Race en gines sometimes engines will just sit prop rocking back forth after being flippedan indication too-hot glow plug burning fuel away piston mak ing flip-starts virtually impossible rheostat must adjusted contacts touch airplane glow plug has very faint glow will give decent combustion range quick restarting As always comments photos solic ited appreciated Mini-Electrics/SruII Continued page 92 power Has ever happened spite having worked hard keep weight minimum adding lastminute details putting really nice finish often brings flying weight Mini-Electric little higher intended model youre building neat kit set great plans turns out just little bit larger size recommended Mini-Electric power sun dry reasons sometimes find power available quite sufficient get hoped-for flying performance some simple things can coax lit tle power endurance Mini-Electric systemand some things should try First make sure flight battery cells OKnot vented cooked leak ing Damaged ones will need replaced Second make sure propeller ap propriate size pitch Above dont go larger higher-pitch prop obtain power Such prop likely give less thrnst worse can overheat possibly damage motor Remember slow motor down larger prop higher current converse also holds highest threshold current want little mo tors operate about 21/2 2 3A amps under 3 amps Sure going above levels short periods 31/2 4 amps wont pose immediate risk cooking motor battery general sport flying decent longev ity motors stay 3 amps below maximum recommended current re fers current drawn operating ground bench test so-called static load air prop will unload little will speed up causing current drop about 14 amp have access test meter can measure up 5 amps current fine tuning little electric mo tors finding right prop safe max imum power becomes very easy Otherwise stick recommended prop size Third make sure motor bearings free tiny drop oil helps gear mesh between pinion spur gears free binding little loose side much better tight fit least bit binding will render MiniElectric gutless blob motor has plastic pinion make sure cracked slightest hairline crack often dif ficult detect will distort under load sap tremendous amount power Since can assume have overcome charging problems building recoinContinued page 172 Print carefully shipping label UU 0 1975 July first issue 01976 0197701982 0197801983 01979sold89840 1980Out-9*9860198101986 Enclose aseparate $2200 check set ordered NO CASHNO CHARGES rI IU IU II II Name II Street Address II cityState ZIP Make checks payable AMA Send orders Academy Model Aeronautics 1810 Samuel Morse Dr L on VA 22090 September 1988 169 40 CC/24 CU IN AMA CENrE5FO5 Collectors Notice Just released AMA Museum BACK ISSUES Model Aviation magazinesNEW original car tons sale YEAR SETS ONLY Check selections below send SEPARATE $2200 CHECK individual set Orders will filled first-come basis set request sold out check will returned being cashedf Limited Quantities Sets Are Complete mended field charger lets proceed real soup-ups easiest ways obtain little additional power endurance boost well using higher capacity flight cells Most motors make use small 50 mAh cells interest weight savings general last place look weight savings flight battery Its equiva lent saving weight Rubber model skimping rubberusually bad idea case Mini-Electrics its mistake another reason very small 50 mAh cells have much higher internal resistance larger cells As result de liver less energy proportion weight larger eg 100 mAh cells example 40% 7-gm savings flight battery weight would counter acted 60% loss delivered energy Try system uses 50 mAh cells substitute 70 mAh cellsor better yet 100 mAh cells will notice im mediate small increase power po tential much longer runs addition since will charging lower per centage maximum charge larger cells will less sensitive overcharge therefore significantly less vulnerable curring damage mere 4 7 gm extra weight 60- 90-gm model get larger cells mo tor supplier doesnt sell 70 mAh pack sometimes referred 80 mAh measurements indicate closer 70 mAh can obtain six cells about $10 dissecting nine-volt rechargeable battery Radio Shack sells transistor nine-volt rechargeable battery catalog No 32-126 $995 General Electric EverReady also market similar 9V re chargeable battery although have tried Some larger RC supply houses carry 100 mAh cells Ace RC example offers high-quality Sanyo 100 mAh cells $350 SR Batteries also handles excellent 50 150 mAh cells other hand about using strategy cells power done care simple move can really add punch mini system First lets discuss few basics commercial mini-electric motor systems use essentially same motor al though differing gear ratios Most intended primarily use two cells exception Knight Pridham KPO1 comes three 50 mAh cells motors usually geared propped draw static current safe level approximately two amperes Remember the motor loaded slowed down current will draw Conse quently lower gear ratio motor-to prop turning rate bigger prop higher current Therefore can add cells provided make sure propeller size small enough keep current below three amperes results tests various sys tems showed following Three cells seem perfectly OK VL fact because its high 71 gear ratio per forms much better three cells does two stock prop draws just about three amperes three cells VL sells 50 mAh three-cell battery works well would recommend 70 mAh 100 mAh pack might also experiment 6-in Peck prop instead Teru Aero prop provided Dont go larger prop however current may get too high MRC system really peps up three cells 70 mAh capacity sug gest go small 5-in prop trim 6-in prop comes unit keep current down Unfortunately plastic pinion gear MRC weak link may last indefinitely three-cell power Ferrell Enterprise motor works very well three cells 70 100 mAh capac ity Try smaller 4/2-in Williams Bros nylon prop instead standard 5 1/2-in Use smallest prop does job three-cell 50 mAh battery standard KPOl system Dont go four cells However using three cells ca pacity 70 100 mAlt will provide real boost power Just two such cells inciden tally will furnish adequate power Mini-Electric models battery KPO 1 designed easily unclip motor unit can located model Its very simple re place 50 mAh pack 70 100 mAh can also wish easily introduce conventional switch har ness time 70 100 mAh pack re sults slight increase power sub stantial increase motor run ex tends usefulness fine motor system larger aircraft other obvious idea added MiniElectric power go slightly larger motor Unfortunately such motor available commercial ready-to-use sys tem present time However like tinkering have means devising large number Kodak disc camera motors have recently found way surplus market camera motors exactly like standard mini-electric motors except two differences First about /8 longer minielectric ones correspondingly longer magnets rotors Thats advantage because can coax litfie power out larger version second differ ence disadvantage can corrected camera motors wound very fine wire hence will produce power speak three five volts However rewound heavier-gauge wire motors make ter rific Mini-Electrics Furthermore selecting appropriate pinion spur gears rewound minicamera motor can pick gear ratio spe cifically tailored models need High ratios 61 71 best swing ing large props high-drag models such WW biplanes lower ratios down 251 31 used smaller higher rev ving props such multi-motor pro jects RC servo gear sets excellent purpose Sources mini-camera motor clude Edmond Scientific 101 E Gloucester Pike Barrington NJ 08007 Jerryco Inc 601 Linden P1 Evanston IL 60202 Write catalogs Winding own motor should snap go back slot car days rewinding motors favorite pas time Ive built about 25 little cus 172 Model Aviation Mini-ElectricslSrull Continued page 169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O-120 SEND $300 FOR COMPLETE CATALOG OF FINE KITS IKON NWST 4PO Box 306 MA Post Falls ID 83854 208 773-9001 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & pre-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut fuel proof vvinoucnw premium l thin ical horizontal text om lengths olors vinyl 6 typestyles inc Military Block ted upright text high Priced right no minimum charge example can have AMA number 2 high text color $300 H orders processed upon receipt shipped via first class mail VINVLWRITE CUSTOM LETFERING 16043 Tulsa Street Granada Hills CA 91344 818 363-7131 between Noon 6PM pst order C4 res add tax fly cx & sum sin oa. veer no MU 9169 Call write complete info pack & sample ITS FREE Fly VINYLWRITE Custom Lettering model today torn motors tells cant difficult Two custom motor combina tions have found work well Rewind #30 wire 31 gear ratio 6-in Peck-Polymers prop two 100 mAh cells b Rewind #32 wire 61 gear ratio 7-in Peck-Polymers prop three 100 mAh cells latter motor system powers 26-inspan Curtiss OC-2 biplane 150 sq area 4 oz weight flies great three 100 mAh cells routinely provide beau tiful flights 1 2 mm want try hand making couple custom mini-motors dont mind rewinding own new company called HiLine Ltd PO Box 1283 thesda MD 20817 sells tinkerers double mini-motor kit $1295 plus $150 post age contains three Kodak motors case goof up rewind wire two sets gears shafts etc plus rewinding/as sembly instructions HiLine also sells parts kit hand-held field charger de scribed earlier timer $1995 plus $200 shipping Send pre addressed stamped envelope price list items way doubling power minielectric motors course gang two motors single spur gear photos show such dual motor system couples two rewound HiLine motors 61-ratio spur gear Power three 150 mAh cells 8-in Peck prop enough 250 sq model weighing 8 10 ox Total weight illustrated dual motor system 60 grams Dual mo tors course will draw twice power flight battery does single motor Multi-mini-motor systems ideal multi-engined Free Flight Scale models Scale subjects heretofore unthink able Free Flight now no big deal demonstrate point ourselves built flew 42-in-span Do-X few tips typical multi-engine models powered Mini-Electrics wing area multi should scaled up roughly number motors two-cell twin motors try model wing area between 150 240 sq three-cell twin motors go 200 280 sq Wing loading should kept between three five ounces per square foot lower better Prop diameter multis often limited reason lower gear ratio motors usually suitable some cases lower gear ratios found conunercial units will beneficial Thats advantage customizing own mo tors Suitable plastic props multis diameters 4 5 made Kaysun Oldtimer Models carries North Pacific Peck-Polymers Wil liams Brothers course can also make own props scalelike three- four-bladers Rule wiring multimotor motors should wired together Other wise primary advantages multi electrics would lost almost perfect auto matic synchronization Basically can wire multis together parallel series Lets take example Say have twin using two three-cell motors draw ing 2 amperes current illustra tions shows two possible arrangements either case need double battery en ergy single motor system series arrangement would use battery six cells say 70 mAh capacity draw 21/2 amps current parallel arrangement would use three cells 150 mAh capac ity draw five amps current bat tery advantage series setup higher voltage lower losses battery because lower current advan tages parallel setup include easier charging three cells still can use standard field charger second ad vantage parallel wiring will use much reliable robust battery less chance single cell go bad less problem cell balance etc Overall prefer parallel system its simplicity reliability four-motor six-motor airplanes eight 10 12 etc same princi ples apply although options available basic requirement pair up opposite-side motors example out board left outboard right same cells Another drawing illustrates enough various alternatives give idea parallel-wired multis cells used flight battery pack have higher capacity commonly used conventional single-motor MiniElectric Cells 150 270 higher capacity may necessary twins 150 mAh- 270 mAh-capacity cells about correct size Radio Shack sells 150 mAh N size packages two $499 catalog #23-121 Ace RC sells San yo 270 mAh cells $390 SR Batter ies carries high quality cells 150 mAh 300 mAh higher capacity would like give twins try dont mind building two wings Hand ley Page W8b construction article illu strates example new breed Mini-Electric Free Flight Scale models Re member Free Flight Dornier Do-X now practical reality Lets cut balsa Handley Page/SruII Continued page 95 pieces cover lightweight white Japanese tissue Lightly water spray tissue shrinkage dry brush three four thin coats nonshrinking dope such Sig Lite Coat buty rate clear brushing lacquer sure paper wood surfaces sealed spray couple very fine coats silver dope lacquer Theres no need load up thick opaque finish light uniform coverage adequate particular aircraft modeled G-EBBI has somewhat tricky attractive trim dark blue stripe edges fuselage longe rons well outlines vertical fin/rudder assembly marked stripes drafting pen filled thinned blue enamel brushed interior stripes fine brush Doing somewhat tedious looks pretty good Registration letters can masked sprayed onor cut black tissue other fuselage lettering rub-on dry transfers drawn pen ink let tering guide Handley Page logos fin nose inked onto piece silver-doped tissue stuck Continued page 174 September 1988 173 P Off M CATAM I