Radio Control Electrics Bob Kopski TWOFERS time month gonna explore two topic areas first discussion comparison several large motors Theres comparatively little information readily available subject hope coverage will prove useful considering moving up power system size Basic Electricity Part 2 will pickup last months installment ended con tinuing short course aimed simplifying confusing science stuff Large motors Its no secret folks first try hand Electric comparatively small-size power systems makes lots sense because its lowest-cost way finding Out just much fun Electric can smaller systems far easiest charge theres nothing small about performance can provide either fact have maintained along small systems can provide about much performance large systems thats feel should no Electric competition classes based 'size' least now Nevertheless reasons con sider moving up larger power installa Handling motor brush/commutatOr heat L-R Unger 18s massive finned-alumi num heat sink Robbes large vents cooling air both air circulation around motor vital carrying off heat tions course models can larger some folks like Some feel better large machine poorer weather addition larger more-powerful Electrics will ground-handle much better though larger installations costly charging difficult some will find biggies lot funand fun course hobby anyway Lets take closer look several large motors lead photo shows six motors about same size Electric motor size~ confusing term because no established standard such gauged have own way dealing its simply categorization much power given product will handle Anyone whos following MAs Electric articles beginning September 1983 knows favor relat ing electrical power model parameters other way around depending upon primary interest user other words model thats big weighs much needs much elec trical power fly desired fashion duration performance determined battery size explained great detail series table included lists certain parameters statistics motors used presentation large motors existence have Anyway turns out six motors five pro peller combinations tested motor probably inappropriately included Its Astro ferrite 25 nothing wrong motorits just Three kinds large-motor prop adapters LR Unger uses collet-ilke arrangement wherein drive washer wrenching fiats has tapered Inner bore rides up tapered chuck prop tight ened Astro uses set screw hold hexsided prop nut Keller 50124 has set screw riding slotted flat armature shaft other five could easily handle power theyre bigger plan retest motor along some others nearly its equal future Mean results included information IN PUT POWER IN WATTS mu Motor ~ t t* g AVR10-1514-1814-lU17-2411-lB15-24 8000100 a9000140140121127126 C 0197181164166175165 11000266243217215226215 12000280286301285 12500344 13000373380 AVR9-1413-2011-1615-2311-1413-20 700099 7500120 8000145128121122126 8500176158 9000214189171177185171 9500251223 10000265233241256240 10500300 11000367318322321 AVR9-1210-1711-1414-229-1114-lU 600010891 6500135113 7000171142133143 7500216161162175187 8000214199197215198 8500237232237 9000318287281280 9500329329 10000392 AVR8-1210-1410-1213-IS7-1013-19 550010441 136 133116 6500181 146134131144 7000233 186165164181166 7500227203202203 8000248246247 8500294301 9000364 AVR7-109128-1012-186-811-15 45009980 500014011298112 .5500194148132129147134 6000195173166175 N6500216225 7000275285 7500343 wt oz 14 18% 13% 14% 12 15 data based single sample motor/prop believed cor rect AVR input voltage input power product voltage current amps Voltage varIed obtain desired rpm value Data reteais part prop its rpm set power level motor motors run about same efficIency over ranges shown use data table select approximate power watts desired model decide approximate size prop want use Example 250 watts large prop desired Look 116 g ro data Astro 40 cobalt Keller an~ger 18 liver power 8000 Examine AVR voltage number cells will required Astro needs about 12 volts Keller something less 19 volts Unger somewhere between same size amp-hr cells Astro would fly shortest time Keller longest wanted use Astro get longer flights switch 96 prop add couple cells bat tery example cieriy shows motors can same jobyet differ operating voitagelcurrent characteristics 52 Model Aviation up pressing radio noise electric motors L-R Astro has bypass capacitor between motor leads connector end Keller uses built-in capacitorsone brush motor housIng tween brushes Robbe U nger motors use add-on external capacitors Getting spring tension motor brushes L-R Astro uses conventional compression spring brush rides guide tube Easy replace screw-on cap Robbes large brushes use large coiled clock springs Now some details motors run benchstatic-tested using lab-type power supply instead batteries high-power supply easily-adjusted output voltage given motor/prop combination could run up over wide useful range power levels Its remote-sensing supply means voltage values given voltages right motor brushes data taken during several-hour period same day done air load test samples would same Remember prop does work moving air cooler warmer air moist/lessmoist air represent different burdens motor hence electrical power required given prop rpm Motors props merely devices convert stored energy batter ies moving air purposes motor comparison same props run motor power supply adjusted desired rpms motor voltage current recorded productpoweris given table various combinations props used varied diameter 8 12 one-inch steps 6-in pitch Top Elite Super M used throughout doesnt mean other sizes brands cant used its just make reasonable representative selection props drilled fit various prop adapters balanced keep test props aside used motor tests flown risk breakage assures data take various times same props although have no similar control over shop air As coincidence just due nature prop supply wound up using almost same prop sizes published December 1984 Ampere Flyer doing same job fact Unger 18 characterized issue ex actly same same serial number used Now dont know what prop brand used Europe surely dont have feel what test air like guess what raw data Continued page 149 five large motors used gathering data table LR Astro 25 ferrIte Astro 40 cobalt Leisure-supplied Keller 50124 cobalt Robbe 50/14 SE cobalt Unger 18 cobalt Average weight less 14% oz typical plane would weigh about 8 lb Motors shown list $75 over $150 Se e 0 C 0 ~4$\ 4e 4$ 04$ \- YORK ROAD TWAONIUM TIMONIUM RD EDEftICGROUNDS BALTIMORE / oS TIMONIUM RD EAST EXIT 16 OFF OF INTERSTATE 83 q4TO MD STATE FAIRGROUNDS TIMONIUM FAIR GROUNDS TIMONIUM MARYLAND FOR INFO CONTACT MARC DIRECTOR Dan Yarchin 6331 Red Cedar Place Baltimore Maryland 21209 301 358-8819 SPONSORED BY THE RADIO CONTROL MODELERS OF BALTIMORE April 1985 53 want try something different exciting both ends towline try aero towing dont have start off exotic mega-buck Scale bird either Dust off old floater rig simple tow release nose have tow bird want workhorse rather some sleek Pattern ship gents Munich using ships 60 90 cu displacements fifth- quarter-scale ships really want some fin challenge launching partner spotlanding contest Hes got make dead stick after might get old flying field back youre almost sure win free lunch him Back lathe January column mention made some pretty fine publications available wrong price SFVSF TechnicalAnthology goes $1250 $10 stated Have sent some money support USA F3B team Good lift Dan Pruss 131 E Pennington Ln Plainfleld IL 60544 RC Electrics/Kopski Continued page 53 quite close agreement published AFT lends lot credibility confidence own feelings about whats presented highly-detailed description Unger 18 can found December 1984 Ampere Flyer electrical data measured digital volt amp meters rpm read analog tach estimated accuracies 2% respec tively two electrical parameters accuracy plus resolution tach estimated ase absolute accuracies important relative results motors run over load power input ranges would personally use own planes As noted times before conservative approach Electric want motors batteries whatever run well last long help assure dont push anything Thus some motors may advertised capable running higher power levels generally hold operating conditions below maximum Also practical reasons usually dont bother testing much beyond 20 volts because Id rather fly cellsits too much trou ble charge such pack same sense usually wont test much beyond 20 amps because Id rather have some reasonable flight duration Besides such heavy currents tend reduce system effi ciencies rapidly due PR losses studying table youll notice motors tested same rpm limits same props general ly because either operating voltage current reached upper limit Signal Guard blocks random noise off-frequency signals can cause loss control air land RO models Signal Guard responds sig nals its own precisely tuned fre quency ignoring static noise craft itself Plus additional amplification allows control operators visual limit cared test Thus some motor large prop would tend draw high current relatively low applied voltage inverse might true another motor Among other things could due nature armature winding design some intended application motor See February 1985 MA Thus other parameter might limit first course condi tions some in-between prop sizes would permit both voltage current top out about same time thus producing highest possible power levels listed Finally some missing obviously desirable test points result oversight during hectic testing Sorry want spend time flying less time money repairing crashed model Signal Guard answer Call toll-free 1-800-468-8215 order Signal GuardTM major credit card send $150 check money order PO Box 30179 Portland OR 97230 Oregon call collect 503-257-0912 So does use informa tion select motor impor tant consideration particular appli cation example youre primarily interested long lazy sport flying choose motor/prop produces necessary power level relatively higher voltage lower currenta given bat tery will last longest other hand prefer highpower bursts short duration some competitive reason go other way around Select motor/prop uses fewest smallest cells lightest-weight pack will still meet current de mand desired short motor run time theres intermediate approach should appeal hotter sport April 1985 149 90 day warranty cted dealerships available fliera sort combination approach can choose motor/prop battery capable producing rather high power levels reasonable motor run time control system flight high-quality elec tronic speed control control feature allows pilot ease off power preserve battery charge hence extend flight time required pour juice some powerintensive maneuver called Whatever desired application enough data such com bined MAs earlier Electric how-to articles can assured achieving desired large-plane flightperformance goals As suggested earlier its feasible test motor possible prop cannot find just right combination motor prop operat ing power-level tables just use different prop Remember lowering pitch reduces power increasing does opposite Also feel free trim prop diameter in-between sizes Again reducing diameter reduces power vice versa sure balance props after such trim job fashion can select motor purchase varying props cell-count attain very wide range operating power performance levels summary motors characterized perform very well similarly will good job flying some larger plane fact within limits measurement accuracy prop suitability again clear its prop motor determines electrical power required battery exactly what Ive written several times before its reason no fear doing article As expected cobalts some what lighter efficient ferrites cost no differences big enough prevent consideration products What requirement very least cell count very smallest current drain Great several motor prop/battery combinations will job can choose motor fea tures like best photos illustrate some Consider differences cooling methods prop adaptors mounting requirements slight variations weight consider availability As far can see motors should work well long time right applica tion purpose find best motorI dont think such exists Its like trying find best car best tennis racket best HandLaunched Glider short unless dictated some very special application require ment its individual matter preference choice Basic Electricity Part Two Last months column presented some simple electrical terms voltage current showed some analogies water pressure flow Youll recall voltage likened depth water over head tank current circuit unlike water flow through aquaresistance represented pipe diameter Also column said electrical power motors product multiplication voltage current Specifically power watts equal volts times amps higher power work can done given time Lots elec trical power can fly given plane up higher rate climb less electrical power Further clear voltage requires cells battery current demand drains given battery quickly larger plane requires larger motor capable han dling higher voltage/currents needed produce higher power Lets back up little start out simply Suppose consider flashlight has battery lamp lamp really small resistance wire connected battery results current flow lamp load battery voltage times current flows power delivered lamp power produces heatthe small resistance wire ele ment gets extremely hot glows brightly similar though bigger example - For Foam Its Best Deal Best PEANUT SCALE MODEU Kits $895 ZEROMILES M-I8 PIETENPOLDRUINE PIPER cusCOUGAR ANDRESONGIPSY MOTH MUSTANGLACEY M-lOGANAGOBIE SPORT MODEU BABY ACE$849 ONE NITE 28$695 ONE NITE IS$695 STRINGLESS$495 PECK ROG$198 RADIO 3LIIdPS CONTROLLED II sad 13 FOOT LONGKITS OR READY TO FLY NOW IN THREE COLORS GRAY ORANGE YELLOW LOW PRICES CATALOG No 25 $150 PHONE 819 442-4636 619 489-8675 LA MESA CA 92041 Model Aviation LLL iii eacn ve Marina Del Rey UA ~i 1-624 FOAM WING CORES TOM FOAM CUTTING iiwd PRAIRIE BIRD T $598 Custom Cut i- iau 1u ruse IS OCEAN STATE AEROMODEL ENGINEERING$14995 21 Jeyc Dr ~ Dealer & Kit Weat Warwick RI 02893Manufacturers WS4 4018288813Inquiries Invited Coming Soon e F8F BearCat Modelers Choice GMP EPOXIES High Quality Model Construction Jr Kwik Set 6 Minute5 oz $595 Kwik Set 6 Minute10 Os $995 Giant Kwik Set 6 Minute16 os$1395 Half FastlOMinutelOoz$895 GMP AIRCRAFT INSTRUMENTS 80in31161/4318112$ 149 40 3/4 inch $149 EASY OFF PULLER proper tool removing drive washersand flywheels $ 795 Gas Model Products 8773 Russet Dr Cincinnati OH 45239 513 385-7398 out e8 dealer order Ante Poat add $150 electric clothes iron Power levels 1000 watts typical household irons takes lot power heat keep such implement hot light typical flashlight former much bigger job done power needed examples electrical power input resistive loads produces heat and/or light relationships elec trical terms involved given Ohms Law can expressed very simple arithmetic expression written three different ways 1 Voltage ent x resistance 2 Current age/Resistance 3 Resistance age/Current case two terms known third unknown may found easily example lets say flashlight battery consisted two cells having cell chemistry produces 15 volts cell terminals cells properly installed typical flashlight con nected series total voltage sum two three volts Now lets say flashlight lamp has resistance 12 ohms typical value informa tion current flowing lamp can found formula 2 /12 current amps V voltage R resistance ohms Suppose now werent able see light lamp knew some current being taken battery some kind load might know because connected multimeters pictured last month such fashion battery current output read same lamp above current meter would read amp might recon nect multimeter read voltage scale use read battery voltage would say 3 volts could easily determine circuit load resistance formula 3 R 3/1/4 e divided one-fourth hms Cash Check Stamps 32 Page Tabloid size illustrated DISCOUNT Catalog Sent 1st Class Mail COMET COX FLYLINE FOX GOLDBERG GUILLOWS JETCO K&fl PACTRA PECK POLYMER PERFECT SIG- STERLiNG SULLIVAN TOP FLITE & OTHERS PENN VALLEY HOBBY CENTER 917 1 Main 3t Lana1sPa 19146 21Sf 865 t268 3680010 SPARROWHAWK 1/32 SCALE PLASTIC MODEL KIT AJS US Navy Sparrowhawks operated two dirigibles aircraft carrier during 1930s among colorful aircraft aviations Golden Age KIT FEATURES U Decals permit finishing model six different Sparrowhawks Two types wheels hard flexible tires U Monofilament rigging U Detailed interior Send $1 complete catalog kits accessories Dept MA WILLIAMS BROTHERS INC 181 PAWNEE ST SAN MARCOS CA 92069 Just exactly use multimeter simple measurements will covered future column now gonna move learn about electrical parameterpower stated above power product voltage current Thus formula relationship Power age x Current P power P expressed watts Look above formulas use little imagination can see power can related circuit load resistance example formula 1 know V Suppose use equality stuff left side equals sign exactly same stuff right side equals sign can used stead other place V formula power Accepted arithmetic practice allows done have P I P IxIxR identical P red PR x needed Similarly should clear P V x V/R Now weve written formulas lets show can put use calculating power used light bulb flashlight Although going three different ways results going same time First lets use volts amps P 3 x att Next well use current resistance P x 12 x 12 = Y4 watt Finally well use voltage resistance P 2 3/ watt April 1985 151 FIBERGLASS & FOAM V CONSTRUCTION FAI & AMA PATtERN 60-61 ENGINE #84 SPAN 704 sq AREA WEIGHT 8 LBS DEPENDING ON EQUIP BASIC KIT$10795 DELUXE KITS15995 Call 10U AM IC 9101 PM Mail-Sal 1115A & MASIER CARD L S L MODEL DEALER & 01ST6000 BCPRODUCTS INQUIRIES INVITEDf513 341-0012 7342 6dg COiliI DnIonlI 0140 46247 AMERICAN JUNIOR .404 Interceptor new A-P404 foldIng wing interreptor lao refresher count Have Fun II youve never Ilown youll fhrillaofhewingsunloldiotosoarlogsi5htllyoUhavC flown heloreif will come back Now can oson ol GREATAMERICAN JUNIOR CLOSSICSYonII love It.and ao will everyone else 404 BuIlder lOt$395 404 AIU595 404 RTF795 74 Glider195 Boa 548 743-in-l Pak495Oregon City 0R97045 See year Oubby Oealer c stock rely order 11001 order direct Poet auc aud 0odliOu Chaeuee 1300 foe first model plus 1091 oddrtluOal RCFS II RADIO CONTROLLED FLIGHT SIMULATOR John Kallend FOR APPLE 11 lie GREAT AS TRAINING AID FOR BEGINNER OR -PPm PIAJY AEROBATIC INCLUDING SPINS AND SNAP ROUS CONFIGURE FOR LARGE VARIETY OF MODELS FROM TRAINERS TO HOT AERORATIC MODELS USE WITH DAVE BROWN PRODUCTS DUAL JOY STICK TRANSMrITEW FOR THE MOST ACCURATE SIMULATION OF R/C PLYING CAN BE USED WITH ANY APPLE COMPATABLE JOYSTICK IT EVEN HAS DUAL RATE CONTROL SENSmVITY NOSE BEGUIREI APPLE II PUll 48K sInI E II WITH BIlE DRIVE AND AR APPLE COMPATARLE JOY 551CR OR DAVE BROWN PRODUCIS DUAl JOYSTICIC TEANIMmEB DAVE BROWN PRODUCTS Notice earlier discussion using hundreds watts turn large propellers fast takes less watt light flashlight So whats have motors batteries Electrics hangs together friends Stay tuned youll have lot insight Electrics work tune out maybe thisll help win some future contestsif meantime please direct ques tions SASE author Happy Electric landings Bob Kopski 25 West End Dr Lansdale PA 19446 RC Old-Timers/Mathews Continued page 55 Its glue Recently laying some laminated outlines down flashed through mind way Hank Struck others should have Available Now Commodore lLZ4\-\~4 V 4860 LAYHIGH HAMILTON OHIO 45013 done designs dawned us bent wire tubing original ly used Apache Cabruler forth werent done laminated balsa simply because nitrocellulose Ambroid Comet etc glue available adhesive such simple thing spray three four layers /16 / whatever dilute ammonia water coat layers aliphatic resin glue Sig Bond etc pull around form pins Hank likely now uses technique himself try Ambroid some time Weve seen TV commercials ask Wheres beef time another modelers must have asked Wheres CG weve built kit manufacturer has done work us shows us plans center gravity CG supposed fact better approximately shows us its supposed model going fly well crunch comes weve got latest masterpiece completed ready flight seldom happens CG has come out money want new plane live weve got add some ballast plane make CG move its sup posed Sure can use age-old cut-and-try method may too time-consuming difficult some cases What neat solution problem published recent edition news letter Lehigh Valley PA RC Club Tom Bilheimer editor order use method described youll need accurate scalepreferably graduated ounces Youll also need accurate ruler yardstick might better scheme described makes use princi ple balancing moments plans show location CG Lets say supposed 375 behind leading edge LE wing Since may convenient meas ure different fixed spot model lets use tip spinner end crankshaft Lets seethe CG should 1075 point Hmmm After finding marking balance point new model find CG actually 10375 reference point means plane nose-heavy weve got add some weight tail Wed like add little weight possible well put near tail possible Measuring plane find can add some weight inconspicuously point 31 inches reference point much weight find out answer question well have use little arithmetic multi plication division some algebra will multiply distance reference point nose location actual CG weight model add product distance reference point place can add ballast times unknown added weight divide sum models weight unknown added weight Well set 152 Model Aviation Complete DIN Line ofFx~ - Quality Finishing Products DIN Pto FESSIONALS CHOICE Kin Craft Mig 14323 TwIn Ridge Court Ashland Kentucky 41101 606 928-4763 ASK FOR US AT TOUR FAVORITE HOllY SHOP GONTIOLINI TillS PROFILECOMBA 7RA T WIDE & NARROW WEDGE 75 -- 6 Capacities INIFLOW & STIIDD Guiton Dliii Fuels Ingredients Fof detailed brochuaCOc stamps/check oisi CAROLINA-TAFFINDER 8345 Delhi Road charleston Hgts. SC 29418 803-563-7169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O120 SEND $200 FOR COMPLETE CATALOG OF FINE KITS IKON NWST ox 566 Auburn WA 98071 206941-8248
Edition: Model Aviation - 1985/04
Page Numbers: 52, 53, 149, 150, 151, 152
Radio Control Electrics Bob Kopski TWOFERS time month gonna explore two topic areas first discussion comparison several large motors Theres comparatively little information readily available subject hope coverage will prove useful considering moving up power system size Basic Electricity Part 2 will pickup last months installment ended con tinuing short course aimed simplifying confusing science stuff Large motors Its no secret folks first try hand Electric comparatively small-size power systems makes lots sense because its lowest-cost way finding Out just much fun Electric can smaller systems far easiest charge theres nothing small about performance can provide either fact have maintained along small systems can provide about much performance large systems thats feel should no Electric competition classes based 'size' least now Nevertheless reasons con sider moving up larger power installa Handling motor brush/commutatOr heat L-R Unger 18s massive finned-alumi num heat sink Robbes large vents cooling air both air circulation around motor vital carrying off heat tions course models can larger some folks like Some feel better large machine poorer weather addition larger more-powerful Electrics will ground-handle much better though larger installations costly charging difficult some will find biggies lot funand fun course hobby anyway Lets take closer look several large motors lead photo shows six motors about same size Electric motor size~ confusing term because no established standard such gauged have own way dealing its simply categorization much power given product will handle Anyone whos following MAs Electric articles beginning September 1983 knows favor relat ing electrical power model parameters other way around depending upon primary interest user other words model thats big weighs much needs much elec trical power fly desired fashion duration performance determined battery size explained great detail series table included lists certain parameters statistics motors used presentation large motors existence have Anyway turns out six motors five pro peller combinations tested motor probably inappropriately included Its Astro ferrite 25 nothing wrong motorits just Three kinds large-motor prop adapters LR Unger uses collet-ilke arrangement wherein drive washer wrenching fiats has tapered Inner bore rides up tapered chuck prop tight ened Astro uses set screw hold hexsided prop nut Keller 50124 has set screw riding slotted flat armature shaft other five could easily handle power theyre bigger plan retest motor along some others nearly its equal future Mean results included information IN PUT POWER IN WATTS mu Motor ~ t t* g AVR10-1514-1814-lU17-2411-lB15-24 8000100 a9000140140121127126 C 0197181164166175165 11000266243217215226215 12000280286301285 12500344 13000373380 AVR9-1413-2011-1615-2311-1413-20 700099 7500120 8000145128121122126 8500176158 9000214189171177185171 9500251223 10000265233241256240 10500300 11000367318322321 AVR9-1210-1711-1414-229-1114-lU 600010891 6500135113 7000171142133143 7500216161162175187 8000214199197215198 8500237232237 9000318287281280 9500329329 10000392 AVR8-1210-1410-1213-IS7-1013-19 550010441 136 133116 6500181 146134131144 7000233 186165164181166 7500227203202203 8000248246247 8500294301 9000364 AVR7-109128-1012-186-811-15 45009980 500014011298112 .5500194148132129147134 6000195173166175 N6500216225 7000275285 7500343 wt oz 14 18% 13% 14% 12 15 data based single sample motor/prop believed cor rect AVR input voltage input power product voltage current amps Voltage varIed obtain desired rpm value Data reteais part prop its rpm set power level motor motors run about same efficIency over ranges shown use data table select approximate power watts desired model decide approximate size prop want use Example 250 watts large prop desired Look 116 g ro data Astro 40 cobalt Keller an~ger 18 liver power 8000 Examine AVR voltage number cells will required Astro needs about 12 volts Keller something less 19 volts Unger somewhere between same size amp-hr cells Astro would fly shortest time Keller longest wanted use Astro get longer flights switch 96 prop add couple cells bat tery example cieriy shows motors can same jobyet differ operating voitagelcurrent characteristics 52 Model Aviation up pressing radio noise electric motors L-R Astro has bypass capacitor between motor leads connector end Keller uses built-in capacitorsone brush motor housIng tween brushes Robbe U nger motors use add-on external capacitors Getting spring tension motor brushes L-R Astro uses conventional compression spring brush rides guide tube Easy replace screw-on cap Robbes large brushes use large coiled clock springs Now some details motors run benchstatic-tested using lab-type power supply instead batteries high-power supply easily-adjusted output voltage given motor/prop combination could run up over wide useful range power levels Its remote-sensing supply means voltage values given voltages right motor brushes data taken during several-hour period same day done air load test samples would same Remember prop does work moving air cooler warmer air moist/lessmoist air represent different burdens motor hence electrical power required given prop rpm Motors props merely devices convert stored energy batter ies moving air purposes motor comparison same props run motor power supply adjusted desired rpms motor voltage current recorded productpoweris given table various combinations props used varied diameter 8 12 one-inch steps 6-in pitch Top Elite Super M used throughout doesnt mean other sizes brands cant used its just make reasonable representative selection props drilled fit various prop adapters balanced keep test props aside used motor tests flown risk breakage assures data take various times same props although have no similar control over shop air As coincidence just due nature prop supply wound up using almost same prop sizes published December 1984 Ampere Flyer doing same job fact Unger 18 characterized issue ex actly same same serial number used Now dont know what prop brand used Europe surely dont have feel what test air like guess what raw data Continued page 149 five large motors used gathering data table LR Astro 25 ferrIte Astro 40 cobalt Leisure-supplied Keller 50124 cobalt Robbe 50/14 SE cobalt Unger 18 cobalt Average weight less 14% oz typical plane would weigh about 8 lb Motors shown list $75 over $150 Se e 0 C 0 ~4$\ 4e 4$ 04$ \- YORK ROAD TWAONIUM TIMONIUM RD EDEftICGROUNDS BALTIMORE / oS TIMONIUM RD EAST EXIT 16 OFF OF INTERSTATE 83 q4TO MD STATE FAIRGROUNDS TIMONIUM FAIR GROUNDS TIMONIUM MARYLAND FOR INFO CONTACT MARC DIRECTOR Dan Yarchin 6331 Red Cedar Place Baltimore Maryland 21209 301 358-8819 SPONSORED BY THE RADIO CONTROL MODELERS OF BALTIMORE April 1985 53 want try something different exciting both ends towline try aero towing dont have start off exotic mega-buck Scale bird either Dust off old floater rig simple tow release nose have tow bird want workhorse rather some sleek Pattern ship gents Munich using ships 60 90 cu displacements fifth- quarter-scale ships really want some fin challenge launching partner spotlanding contest Hes got make dead stick after might get old flying field back youre almost sure win free lunch him Back lathe January column mention made some pretty fine publications available wrong price SFVSF TechnicalAnthology goes $1250 $10 stated Have sent some money support USA F3B team Good lift Dan Pruss 131 E Pennington Ln Plainfleld IL 60544 RC Electrics/Kopski Continued page 53 quite close agreement published AFT lends lot credibility confidence own feelings about whats presented highly-detailed description Unger 18 can found December 1984 Ampere Flyer electrical data measured digital volt amp meters rpm read analog tach estimated accuracies 2% respec tively two electrical parameters accuracy plus resolution tach estimated ase absolute accuracies important relative results motors run over load power input ranges would personally use own planes As noted times before conservative approach Electric want motors batteries whatever run well last long help assure dont push anything Thus some motors may advertised capable running higher power levels generally hold operating conditions below maximum Also practical reasons usually dont bother testing much beyond 20 volts because Id rather fly cellsits too much trou ble charge such pack same sense usually wont test much beyond 20 amps because Id rather have some reasonable flight duration Besides such heavy currents tend reduce system effi ciencies rapidly due PR losses studying table youll notice motors tested same rpm limits same props general ly because either operating voltage current reached upper limit Signal Guard blocks random noise off-frequency signals can cause loss control air land RO models Signal Guard responds sig nals its own precisely tuned fre quency ignoring static noise craft itself Plus additional amplification allows control operators visual limit cared test Thus some motor large prop would tend draw high current relatively low applied voltage inverse might true another motor Among other things could due nature armature winding design some intended application motor See February 1985 MA Thus other parameter might limit first course condi tions some in-between prop sizes would permit both voltage current top out about same time thus producing highest possible power levels listed Finally some missing obviously desirable test points result oversight during hectic testing Sorry want spend time flying less time money repairing crashed model Signal Guard answer Call toll-free 1-800-468-8215 order Signal GuardTM major credit card send $150 check money order PO Box 30179 Portland OR 97230 Oregon call collect 503-257-0912 So does use informa tion select motor impor tant consideration particular appli cation example youre primarily interested long lazy sport flying choose motor/prop produces necessary power level relatively higher voltage lower currenta given bat tery will last longest other hand prefer highpower bursts short duration some competitive reason go other way around Select motor/prop uses fewest smallest cells lightest-weight pack will still meet current de mand desired short motor run time theres intermediate approach should appeal hotter sport April 1985 149 90 day warranty cted dealerships available fliera sort combination approach can choose motor/prop battery capable producing rather high power levels reasonable motor run time control system flight high-quality elec tronic speed control control feature allows pilot ease off power preserve battery charge hence extend flight time required pour juice some powerintensive maneuver called Whatever desired application enough data such com bined MAs earlier Electric how-to articles can assured achieving desired large-plane flightperformance goals As suggested earlier its feasible test motor possible prop cannot find just right combination motor prop operat ing power-level tables just use different prop Remember lowering pitch reduces power increasing does opposite Also feel free trim prop diameter in-between sizes Again reducing diameter reduces power vice versa sure balance props after such trim job fashion can select motor purchase varying props cell-count attain very wide range operating power performance levels summary motors characterized perform very well similarly will good job flying some larger plane fact within limits measurement accuracy prop suitability again clear its prop motor determines electrical power required battery exactly what Ive written several times before its reason no fear doing article As expected cobalts some what lighter efficient ferrites cost no differences big enough prevent consideration products What requirement very least cell count very smallest current drain Great several motor prop/battery combinations will job can choose motor fea tures like best photos illustrate some Consider differences cooling methods prop adaptors mounting requirements slight variations weight consider availability As far can see motors should work well long time right applica tion purpose find best motorI dont think such exists Its like trying find best car best tennis racket best HandLaunched Glider short unless dictated some very special application require ment its individual matter preference choice Basic Electricity Part Two Last months column presented some simple electrical terms voltage current showed some analogies water pressure flow Youll recall voltage likened depth water over head tank current circuit unlike water flow through aquaresistance represented pipe diameter Also column said electrical power motors product multiplication voltage current Specifically power watts equal volts times amps higher power work can done given time Lots elec trical power can fly given plane up higher rate climb less electrical power Further clear voltage requires cells battery current demand drains given battery quickly larger plane requires larger motor capable han dling higher voltage/currents needed produce higher power Lets back up little start out simply Suppose consider flashlight has battery lamp lamp really small resistance wire connected battery results current flow lamp load battery voltage times current flows power delivered lamp power produces heatthe small resistance wire ele ment gets extremely hot glows brightly similar though bigger example - For Foam Its Best Deal Best PEANUT SCALE MODEU Kits $895 ZEROMILES M-I8 PIETENPOLDRUINE PIPER cusCOUGAR ANDRESONGIPSY MOTH MUSTANGLACEY M-lOGANAGOBIE SPORT MODEU BABY ACE$849 ONE NITE 28$695 ONE NITE IS$695 STRINGLESS$495 PECK ROG$198 RADIO 3LIIdPS CONTROLLED II sad 13 FOOT LONGKITS OR READY TO FLY NOW IN THREE COLORS GRAY ORANGE YELLOW LOW PRICES CATALOG No 25 $150 PHONE 819 442-4636 619 489-8675 LA MESA CA 92041 Model Aviation LLL iii eacn ve Marina Del Rey UA ~i 1-624 FOAM WING CORES TOM FOAM CUTTING iiwd PRAIRIE BIRD T $598 Custom Cut i- iau 1u ruse IS OCEAN STATE AEROMODEL ENGINEERING$14995 21 Jeyc Dr ~ Dealer & Kit Weat Warwick RI 02893Manufacturers WS4 4018288813Inquiries Invited Coming Soon e F8F BearCat Modelers Choice GMP EPOXIES High Quality Model Construction Jr Kwik Set 6 Minute5 oz $595 Kwik Set 6 Minute10 Os $995 Giant Kwik Set 6 Minute16 os$1395 Half FastlOMinutelOoz$895 GMP AIRCRAFT INSTRUMENTS 80in31161/4318112$ 149 40 3/4 inch $149 EASY OFF PULLER proper tool removing drive washersand flywheels $ 795 Gas Model Products 8773 Russet Dr Cincinnati OH 45239 513 385-7398 out e8 dealer order Ante Poat add $150 electric clothes iron Power levels 1000 watts typical household irons takes lot power heat keep such implement hot light typical flashlight former much bigger job done power needed examples electrical power input resistive loads produces heat and/or light relationships elec trical terms involved given Ohms Law can expressed very simple arithmetic expression written three different ways 1 Voltage ent x resistance 2 Current age/Resistance 3 Resistance age/Current case two terms known third unknown may found easily example lets say flashlight battery consisted two cells having cell chemistry produces 15 volts cell terminals cells properly installed typical flashlight con nected series total voltage sum two three volts Now lets say flashlight lamp has resistance 12 ohms typical value informa tion current flowing lamp can found formula 2 /12 current amps V voltage R resistance ohms Suppose now werent able see light lamp knew some current being taken battery some kind load might know because connected multimeters pictured last month such fashion battery current output read same lamp above current meter would read amp might recon nect multimeter read voltage scale use read battery voltage would say 3 volts could easily determine circuit load resistance formula 3 R 3/1/4 e divided one-fourth hms Cash Check Stamps 32 Page Tabloid size illustrated DISCOUNT Catalog Sent 1st Class Mail COMET COX FLYLINE FOX GOLDBERG GUILLOWS JETCO K&fl PACTRA PECK POLYMER PERFECT SIG- STERLiNG SULLIVAN TOP FLITE & OTHERS PENN VALLEY HOBBY CENTER 917 1 Main 3t Lana1sPa 19146 21Sf 865 t268 3680010 SPARROWHAWK 1/32 SCALE PLASTIC MODEL KIT AJS US Navy Sparrowhawks operated two dirigibles aircraft carrier during 1930s among colorful aircraft aviations Golden Age KIT FEATURES U Decals permit finishing model six different Sparrowhawks Two types wheels hard flexible tires U Monofilament rigging U Detailed interior Send $1 complete catalog kits accessories Dept MA WILLIAMS BROTHERS INC 181 PAWNEE ST SAN MARCOS CA 92069 Just exactly use multimeter simple measurements will covered future column now gonna move learn about electrical parameterpower stated above power product voltage current Thus formula relationship Power age x Current P power P expressed watts Look above formulas use little imagination can see power can related circuit load resistance example formula 1 know V Suppose use equality stuff left side equals sign exactly same stuff right side equals sign can used stead other place V formula power Accepted arithmetic practice allows done have P I P IxIxR identical P red PR x needed Similarly should clear P V x V/R Now weve written formulas lets show can put use calculating power used light bulb flashlight Although going three different ways results going same time First lets use volts amps P 3 x att Next well use current resistance P x 12 x 12 = Y4 watt Finally well use voltage resistance P 2 3/ watt April 1985 151 FIBERGLASS & FOAM V CONSTRUCTION FAI & AMA PATtERN 60-61 ENGINE #84 SPAN 704 sq AREA WEIGHT 8 LBS DEPENDING ON EQUIP BASIC KIT$10795 DELUXE KITS15995 Call 10U AM IC 9101 PM Mail-Sal 1115A & MASIER CARD L S L MODEL DEALER & 01ST6000 BCPRODUCTS INQUIRIES INVITEDf513 341-0012 7342 6dg COiliI DnIonlI 0140 46247 AMERICAN JUNIOR .404 Interceptor new A-P404 foldIng wing interreptor lao refresher count Have Fun II youve never Ilown youll fhrillaofhewingsunloldiotosoarlogsi5htllyoUhavC flown heloreif will come back Now can oson ol GREATAMERICAN JUNIOR CLOSSICSYonII love It.and ao will everyone else 404 BuIlder lOt$395 404 AIU595 404 RTF795 74 Glider195 Boa 548 743-in-l Pak495Oregon City 0R97045 See year Oubby Oealer c stock rely order 11001 order direct Poet auc aud 0odliOu Chaeuee 1300 foe first model plus 1091 oddrtluOal RCFS II RADIO CONTROLLED FLIGHT SIMULATOR John Kallend FOR APPLE 11 lie GREAT AS TRAINING AID FOR BEGINNER OR -PPm PIAJY AEROBATIC INCLUDING SPINS AND SNAP ROUS CONFIGURE FOR LARGE VARIETY OF MODELS FROM TRAINERS TO HOT AERORATIC MODELS USE WITH DAVE BROWN PRODUCTS DUAL JOY STICK TRANSMrITEW FOR THE MOST ACCURATE SIMULATION OF R/C PLYING CAN BE USED WITH ANY APPLE COMPATABLE JOYSTICK IT EVEN HAS DUAL RATE CONTROL SENSmVITY NOSE BEGUIREI APPLE II PUll 48K sInI E II WITH BIlE DRIVE AND AR APPLE COMPATARLE JOY 551CR OR DAVE BROWN PRODUCIS DUAl JOYSTICIC TEANIMmEB DAVE BROWN PRODUCTS Notice earlier discussion using hundreds watts turn large propellers fast takes less watt light flashlight So whats have motors batteries Electrics hangs together friends Stay tuned youll have lot insight Electrics work tune out maybe thisll help win some future contestsif meantime please direct ques tions SASE author Happy Electric landings Bob Kopski 25 West End Dr Lansdale PA 19446 RC Old-Timers/Mathews Continued page 55 Its glue Recently laying some laminated outlines down flashed through mind way Hank Struck others should have Available Now Commodore lLZ4\-\~4 V 4860 LAYHIGH HAMILTON OHIO 45013 done designs dawned us bent wire tubing original ly used Apache Cabruler forth werent done laminated balsa simply because nitrocellulose Ambroid Comet etc glue available adhesive such simple thing spray three four layers /16 / whatever dilute ammonia water coat layers aliphatic resin glue Sig Bond etc pull around form pins Hank likely now uses technique himself try Ambroid some time Weve seen TV commercials ask Wheres beef time another modelers must have asked Wheres CG weve built kit manufacturer has done work us shows us plans center gravity CG supposed fact better approximately shows us its supposed model going fly well crunch comes weve got latest masterpiece completed ready flight seldom happens CG has come out money want new plane live weve got add some ballast plane make CG move its sup posed Sure can use age-old cut-and-try method may too time-consuming difficult some cases What neat solution problem published recent edition news letter Lehigh Valley PA RC Club Tom Bilheimer editor order use method described youll need accurate scalepreferably graduated ounces Youll also need accurate ruler yardstick might better scheme described makes use princi ple balancing moments plans show location CG Lets say supposed 375 behind leading edge LE wing Since may convenient meas ure different fixed spot model lets use tip spinner end crankshaft Lets seethe CG should 1075 point Hmmm After finding marking balance point new model find CG actually 10375 reference point means plane nose-heavy weve got add some weight tail Wed like add little weight possible well put near tail possible Measuring plane find can add some weight inconspicuously point 31 inches reference point much weight find out answer question well have use little arithmetic multi plication division some algebra will multiply distance reference point nose location actual CG weight model add product distance reference point place can add ballast times unknown added weight divide sum models weight unknown added weight Well set 152 Model Aviation Complete DIN Line ofFx~ - Quality Finishing Products DIN Pto FESSIONALS CHOICE Kin Craft Mig 14323 TwIn Ridge Court Ashland Kentucky 41101 606 928-4763 ASK FOR US AT TOUR FAVORITE HOllY SHOP GONTIOLINI TillS PROFILECOMBA 7RA T WIDE & NARROW WEDGE 75 -- 6 Capacities INIFLOW & STIIDD Guiton Dliii Fuels Ingredients Fof detailed brochuaCOc stamps/check oisi CAROLINA-TAFFINDER 8345 Delhi Road charleston Hgts. SC 29418 803-563-7169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O120 SEND $200 FOR COMPLETE CATALOG OF FINE KITS IKON NWST ox 566 Auburn WA 98071 206941-8248
Edition: Model Aviation - 1985/04
Page Numbers: 52, 53, 149, 150, 151, 152
Radio Control Electrics Bob Kopski TWOFERS time month gonna explore two topic areas first discussion comparison several large motors Theres comparatively little information readily available subject hope coverage will prove useful considering moving up power system size Basic Electricity Part 2 will pickup last months installment ended con tinuing short course aimed simplifying confusing science stuff Large motors Its no secret folks first try hand Electric comparatively small-size power systems makes lots sense because its lowest-cost way finding Out just much fun Electric can smaller systems far easiest charge theres nothing small about performance can provide either fact have maintained along small systems can provide about much performance large systems thats feel should no Electric competition classes based 'size' least now Nevertheless reasons con sider moving up larger power installa Handling motor brush/commutatOr heat L-R Unger 18s massive finned-alumi num heat sink Robbes large vents cooling air both air circulation around motor vital carrying off heat tions course models can larger some folks like Some feel better large machine poorer weather addition larger more-powerful Electrics will ground-handle much better though larger installations costly charging difficult some will find biggies lot funand fun course hobby anyway Lets take closer look several large motors lead photo shows six motors about same size Electric motor size~ confusing term because no established standard such gauged have own way dealing its simply categorization much power given product will handle Anyone whos following MAs Electric articles beginning September 1983 knows favor relat ing electrical power model parameters other way around depending upon primary interest user other words model thats big weighs much needs much elec trical power fly desired fashion duration performance determined battery size explained great detail series table included lists certain parameters statistics motors used presentation large motors existence have Anyway turns out six motors five pro peller combinations tested motor probably inappropriately included Its Astro ferrite 25 nothing wrong motorits just Three kinds large-motor prop adapters LR Unger uses collet-ilke arrangement wherein drive washer wrenching fiats has tapered Inner bore rides up tapered chuck prop tight ened Astro uses set screw hold hexsided prop nut Keller 50124 has set screw riding slotted flat armature shaft other five could easily handle power theyre bigger plan retest motor along some others nearly its equal future Mean results included information IN PUT POWER IN WATTS mu Motor ~ t t* g AVR10-1514-1814-lU17-2411-lB15-24 8000100 a9000140140121127126 C 0197181164166175165 11000266243217215226215 12000280286301285 12500344 13000373380 AVR9-1413-2011-1615-2311-1413-20 700099 7500120 8000145128121122126 8500176158 9000214189171177185171 9500251223 10000265233241256240 10500300 11000367318322321 AVR9-1210-1711-1414-229-1114-lU 600010891 6500135113 7000171142133143 7500216161162175187 8000214199197215198 8500237232237 9000318287281280 9500329329 10000392 AVR8-1210-1410-1213-IS7-1013-19 550010441 136 133116 6500181 146134131144 7000233 186165164181166 7500227203202203 8000248246247 8500294301 9000364 AVR7-109128-1012-186-811-15 45009980 500014011298112 .5500194148132129147134 6000195173166175 N6500216225 7000275285 7500343 wt oz 14 18% 13% 14% 12 15 data based single sample motor/prop believed cor rect AVR input voltage input power product voltage current amps Voltage varIed obtain desired rpm value Data reteais part prop its rpm set power level motor motors run about same efficIency over ranges shown use data table select approximate power watts desired model decide approximate size prop want use Example 250 watts large prop desired Look 116 g ro data Astro 40 cobalt Keller an~ger 18 liver power 8000 Examine AVR voltage number cells will required Astro needs about 12 volts Keller something less 19 volts Unger somewhere between same size amp-hr cells Astro would fly shortest time Keller longest wanted use Astro get longer flights switch 96 prop add couple cells bat tery example cieriy shows motors can same jobyet differ operating voitagelcurrent characteristics 52 Model Aviation up pressing radio noise electric motors L-R Astro has bypass capacitor between motor leads connector end Keller uses built-in capacitorsone brush motor housIng tween brushes Robbe U nger motors use add-on external capacitors Getting spring tension motor brushes L-R Astro uses conventional compression spring brush rides guide tube Easy replace screw-on cap Robbes large brushes use large coiled clock springs Now some details motors run benchstatic-tested using lab-type power supply instead batteries high-power supply easily-adjusted output voltage given motor/prop combination could run up over wide useful range power levels Its remote-sensing supply means voltage values given voltages right motor brushes data taken during several-hour period same day done air load test samples would same Remember prop does work moving air cooler warmer air moist/lessmoist air represent different burdens motor hence electrical power required given prop rpm Motors props merely devices convert stored energy batter ies moving air purposes motor comparison same props run motor power supply adjusted desired rpms motor voltage current recorded productpoweris given table various combinations props used varied diameter 8 12 one-inch steps 6-in pitch Top Elite Super M used throughout doesnt mean other sizes brands cant used its just make reasonable representative selection props drilled fit various prop adapters balanced keep test props aside used motor tests flown risk breakage assures data take various times same props although have no similar control over shop air As coincidence just due nature prop supply wound up using almost same prop sizes published December 1984 Ampere Flyer doing same job fact Unger 18 characterized issue ex actly same same serial number used Now dont know what prop brand used Europe surely dont have feel what test air like guess what raw data Continued page 149 five large motors used gathering data table LR Astro 25 ferrIte Astro 40 cobalt Leisure-supplied Keller 50124 cobalt Robbe 50/14 SE cobalt Unger 18 cobalt Average weight less 14% oz typical plane would weigh about 8 lb Motors shown list $75 over $150 Se e 0 C 0 ~4$\ 4e 4$ 04$ \- YORK ROAD TWAONIUM TIMONIUM RD EDEftICGROUNDS BALTIMORE / oS TIMONIUM RD EAST EXIT 16 OFF OF INTERSTATE 83 q4TO MD STATE FAIRGROUNDS TIMONIUM FAIR GROUNDS TIMONIUM MARYLAND FOR INFO CONTACT MARC DIRECTOR Dan Yarchin 6331 Red Cedar Place Baltimore Maryland 21209 301 358-8819 SPONSORED BY THE RADIO CONTROL MODELERS OF BALTIMORE April 1985 53 want try something different exciting both ends towline try aero towing dont have start off exotic mega-buck Scale bird either Dust off old floater rig simple tow release nose have tow bird want workhorse rather some sleek Pattern ship gents Munich using ships 60 90 cu displacements fifth- quarter-scale ships really want some fin challenge launching partner spotlanding contest Hes got make dead stick after might get old flying field back youre almost sure win free lunch him Back lathe January column mention made some pretty fine publications available wrong price SFVSF TechnicalAnthology goes $1250 $10 stated Have sent some money support USA F3B team Good lift Dan Pruss 131 E Pennington Ln Plainfleld IL 60544 RC Electrics/Kopski Continued page 53 quite close agreement published AFT lends lot credibility confidence own feelings about whats presented highly-detailed description Unger 18 can found December 1984 Ampere Flyer electrical data measured digital volt amp meters rpm read analog tach estimated accuracies 2% respec tively two electrical parameters accuracy plus resolution tach estimated ase absolute accuracies important relative results motors run over load power input ranges would personally use own planes As noted times before conservative approach Electric want motors batteries whatever run well last long help assure dont push anything Thus some motors may advertised capable running higher power levels generally hold operating conditions below maximum Also practical reasons usually dont bother testing much beyond 20 volts because Id rather fly cellsits too much trou ble charge such pack same sense usually wont test much beyond 20 amps because Id rather have some reasonable flight duration Besides such heavy currents tend reduce system effi ciencies rapidly due PR losses studying table youll notice motors tested same rpm limits same props general ly because either operating voltage current reached upper limit Signal Guard blocks random noise off-frequency signals can cause loss control air land RO models Signal Guard responds sig nals its own precisely tuned fre quency ignoring static noise craft itself Plus additional amplification allows control operators visual limit cared test Thus some motor large prop would tend draw high current relatively low applied voltage inverse might true another motor Among other things could due nature armature winding design some intended application motor See February 1985 MA Thus other parameter might limit first course condi tions some in-between prop sizes would permit both voltage current top out about same time thus producing highest possible power levels listed Finally some missing obviously desirable test points result oversight during hectic testing Sorry want spend time flying less time money repairing crashed model Signal Guard answer Call toll-free 1-800-468-8215 order Signal GuardTM major credit card send $150 check money order PO Box 30179 Portland OR 97230 Oregon call collect 503-257-0912 So does use informa tion select motor impor tant consideration particular appli cation example youre primarily interested long lazy sport flying choose motor/prop produces necessary power level relatively higher voltage lower currenta given bat tery will last longest other hand prefer highpower bursts short duration some competitive reason go other way around Select motor/prop uses fewest smallest cells lightest-weight pack will still meet current de mand desired short motor run time theres intermediate approach should appeal hotter sport April 1985 149 90 day warranty cted dealerships available fliera sort combination approach can choose motor/prop battery capable producing rather high power levels reasonable motor run time control system flight high-quality elec tronic speed control control feature allows pilot ease off power preserve battery charge hence extend flight time required pour juice some powerintensive maneuver called Whatever desired application enough data such com bined MAs earlier Electric how-to articles can assured achieving desired large-plane flightperformance goals As suggested earlier its feasible test motor possible prop cannot find just right combination motor prop operat ing power-level tables just use different prop Remember lowering pitch reduces power increasing does opposite Also feel free trim prop diameter in-between sizes Again reducing diameter reduces power vice versa sure balance props after such trim job fashion can select motor purchase varying props cell-count attain very wide range operating power performance levels summary motors characterized perform very well similarly will good job flying some larger plane fact within limits measurement accuracy prop suitability again clear its prop motor determines electrical power required battery exactly what Ive written several times before its reason no fear doing article As expected cobalts some what lighter efficient ferrites cost no differences big enough prevent consideration products What requirement very least cell count very smallest current drain Great several motor prop/battery combinations will job can choose motor fea tures like best photos illustrate some Consider differences cooling methods prop adaptors mounting requirements slight variations weight consider availability As far can see motors should work well long time right applica tion purpose find best motorI dont think such exists Its like trying find best car best tennis racket best HandLaunched Glider short unless dictated some very special application require ment its individual matter preference choice Basic Electricity Part Two Last months column presented some simple electrical terms voltage current showed some analogies water pressure flow Youll recall voltage likened depth water over head tank current circuit unlike water flow through aquaresistance represented pipe diameter Also column said electrical power motors product multiplication voltage current Specifically power watts equal volts times amps higher power work can done given time Lots elec trical power can fly given plane up higher rate climb less electrical power Further clear voltage requires cells battery current demand drains given battery quickly larger plane requires larger motor capable han dling higher voltage/currents needed produce higher power Lets back up little start out simply Suppose consider flashlight has battery lamp lamp really small resistance wire connected battery results current flow lamp load battery voltage times current flows power delivered lamp power produces heatthe small resistance wire ele ment gets extremely hot glows brightly similar though bigger example - For Foam Its Best Deal Best PEANUT SCALE MODEU Kits $895 ZEROMILES M-I8 PIETENPOLDRUINE PIPER cusCOUGAR ANDRESONGIPSY MOTH MUSTANGLACEY M-lOGANAGOBIE SPORT MODEU BABY ACE$849 ONE NITE 28$695 ONE NITE IS$695 STRINGLESS$495 PECK ROG$198 RADIO 3LIIdPS CONTROLLED II sad 13 FOOT LONGKITS OR READY TO FLY NOW IN THREE COLORS GRAY ORANGE YELLOW LOW PRICES CATALOG No 25 $150 PHONE 819 442-4636 619 489-8675 LA MESA CA 92041 Model Aviation LLL iii eacn ve Marina Del Rey UA ~i 1-624 FOAM WING CORES TOM FOAM CUTTING iiwd PRAIRIE BIRD T $598 Custom Cut i- iau 1u ruse IS OCEAN STATE AEROMODEL ENGINEERING$14995 21 Jeyc Dr ~ Dealer & Kit Weat Warwick RI 02893Manufacturers WS4 4018288813Inquiries Invited Coming Soon e F8F BearCat Modelers Choice GMP EPOXIES High Quality Model Construction Jr Kwik Set 6 Minute5 oz $595 Kwik Set 6 Minute10 Os $995 Giant Kwik Set 6 Minute16 os$1395 Half FastlOMinutelOoz$895 GMP AIRCRAFT INSTRUMENTS 80in31161/4318112$ 149 40 3/4 inch $149 EASY OFF PULLER proper tool removing drive washersand flywheels $ 795 Gas Model Products 8773 Russet Dr Cincinnati OH 45239 513 385-7398 out e8 dealer order Ante Poat add $150 electric clothes iron Power levels 1000 watts typical household irons takes lot power heat keep such implement hot light typical flashlight former much bigger job done power needed examples electrical power input resistive loads produces heat and/or light relationships elec trical terms involved given Ohms Law can expressed very simple arithmetic expression written three different ways 1 Voltage ent x resistance 2 Current age/Resistance 3 Resistance age/Current case two terms known third unknown may found easily example lets say flashlight battery consisted two cells having cell chemistry produces 15 volts cell terminals cells properly installed typical flashlight con nected series total voltage sum two three volts Now lets say flashlight lamp has resistance 12 ohms typical value informa tion current flowing lamp can found formula 2 /12 current amps V voltage R resistance ohms Suppose now werent able see light lamp knew some current being taken battery some kind load might know because connected multimeters pictured last month such fashion battery current output read same lamp above current meter would read amp might recon nect multimeter read voltage scale use read battery voltage would say 3 volts could easily determine circuit load resistance formula 3 R 3/1/4 e divided one-fourth hms Cash Check Stamps 32 Page Tabloid size illustrated DISCOUNT Catalog Sent 1st Class Mail COMET COX FLYLINE FOX GOLDBERG GUILLOWS JETCO K&fl PACTRA PECK POLYMER PERFECT SIG- STERLiNG SULLIVAN TOP FLITE & OTHERS PENN VALLEY HOBBY CENTER 917 1 Main 3t Lana1sPa 19146 21Sf 865 t268 3680010 SPARROWHAWK 1/32 SCALE PLASTIC MODEL KIT AJS US Navy Sparrowhawks operated two dirigibles aircraft carrier during 1930s among colorful aircraft aviations Golden Age KIT FEATURES U Decals permit finishing model six different Sparrowhawks Two types wheels hard flexible tires U Monofilament rigging U Detailed interior Send $1 complete catalog kits accessories Dept MA WILLIAMS BROTHERS INC 181 PAWNEE ST SAN MARCOS CA 92069 Just exactly use multimeter simple measurements will covered future column now gonna move learn about electrical parameterpower stated above power product voltage current Thus formula relationship Power age x Current P power P expressed watts Look above formulas use little imagination can see power can related circuit load resistance example formula 1 know V Suppose use equality stuff left side equals sign exactly same stuff right side equals sign can used stead other place V formula power Accepted arithmetic practice allows done have P I P IxIxR identical P red PR x needed Similarly should clear P V x V/R Now weve written formulas lets show can put use calculating power used light bulb flashlight Although going three different ways results going same time First lets use volts amps P 3 x att Next well use current resistance P x 12 x 12 = Y4 watt Finally well use voltage resistance P 2 3/ watt April 1985 151 FIBERGLASS & FOAM V CONSTRUCTION FAI & AMA PATtERN 60-61 ENGINE #84 SPAN 704 sq AREA WEIGHT 8 LBS DEPENDING ON EQUIP BASIC KIT$10795 DELUXE KITS15995 Call 10U AM IC 9101 PM Mail-Sal 1115A & MASIER CARD L S L MODEL DEALER & 01ST6000 BCPRODUCTS INQUIRIES INVITEDf513 341-0012 7342 6dg COiliI DnIonlI 0140 46247 AMERICAN JUNIOR .404 Interceptor new A-P404 foldIng wing interreptor lao refresher count Have Fun II youve never Ilown youll fhrillaofhewingsunloldiotosoarlogsi5htllyoUhavC flown heloreif will come back Now can oson ol GREATAMERICAN JUNIOR CLOSSICSYonII love It.and ao will everyone else 404 BuIlder lOt$395 404 AIU595 404 RTF795 74 Glider195 Boa 548 743-in-l Pak495Oregon City 0R97045 See year Oubby Oealer c stock rely order 11001 order direct Poet auc aud 0odliOu Chaeuee 1300 foe first model plus 1091 oddrtluOal RCFS II RADIO CONTROLLED FLIGHT SIMULATOR John Kallend FOR APPLE 11 lie GREAT AS TRAINING AID FOR BEGINNER OR -PPm PIAJY AEROBATIC INCLUDING SPINS AND SNAP ROUS CONFIGURE FOR LARGE VARIETY OF MODELS FROM TRAINERS TO HOT AERORATIC MODELS USE WITH DAVE BROWN PRODUCTS DUAL JOY STICK TRANSMrITEW FOR THE MOST ACCURATE SIMULATION OF R/C PLYING CAN BE USED WITH ANY APPLE COMPATABLE JOYSTICK IT EVEN HAS DUAL RATE CONTROL SENSmVITY NOSE BEGUIREI APPLE II PUll 48K sInI E II WITH BIlE DRIVE AND AR APPLE COMPATARLE JOY 551CR OR DAVE BROWN PRODUCIS DUAl JOYSTICIC TEANIMmEB DAVE BROWN PRODUCTS Notice earlier discussion using hundreds watts turn large propellers fast takes less watt light flashlight So whats have motors batteries Electrics hangs together friends Stay tuned youll have lot insight Electrics work tune out maybe thisll help win some future contestsif meantime please direct ques tions SASE author Happy Electric landings Bob Kopski 25 West End Dr Lansdale PA 19446 RC Old-Timers/Mathews Continued page 55 Its glue Recently laying some laminated outlines down flashed through mind way Hank Struck others should have Available Now Commodore lLZ4\-\~4 V 4860 LAYHIGH HAMILTON OHIO 45013 done designs dawned us bent wire tubing original ly used Apache Cabruler forth werent done laminated balsa simply because nitrocellulose Ambroid Comet etc glue available adhesive such simple thing spray three four layers /16 / whatever dilute ammonia water coat layers aliphatic resin glue Sig Bond etc pull around form pins Hank likely now uses technique himself try Ambroid some time Weve seen TV commercials ask Wheres beef time another modelers must have asked Wheres CG weve built kit manufacturer has done work us shows us plans center gravity CG supposed fact better approximately shows us its supposed model going fly well crunch comes weve got latest masterpiece completed ready flight seldom happens CG has come out money want new plane live weve got add some ballast plane make CG move its sup posed Sure can use age-old cut-and-try method may too time-consuming difficult some cases What neat solution problem published recent edition news letter Lehigh Valley PA RC Club Tom Bilheimer editor order use method described youll need accurate scalepreferably graduated ounces Youll also need accurate ruler yardstick might better scheme described makes use princi ple balancing moments plans show location CG Lets say supposed 375 behind leading edge LE wing Since may convenient meas ure different fixed spot model lets use tip spinner end crankshaft Lets seethe CG should 1075 point Hmmm After finding marking balance point new model find CG actually 10375 reference point means plane nose-heavy weve got add some weight tail Wed like add little weight possible well put near tail possible Measuring plane find can add some weight inconspicuously point 31 inches reference point much weight find out answer question well have use little arithmetic multi plication division some algebra will multiply distance reference point nose location actual CG weight model add product distance reference point place can add ballast times unknown added weight divide sum models weight unknown added weight Well set 152 Model Aviation Complete DIN Line ofFx~ - Quality Finishing Products DIN Pto FESSIONALS CHOICE Kin Craft Mig 14323 TwIn Ridge Court Ashland Kentucky 41101 606 928-4763 ASK FOR US AT TOUR FAVORITE HOllY SHOP GONTIOLINI TillS PROFILECOMBA 7RA T WIDE & NARROW WEDGE 75 -- 6 Capacities INIFLOW & STIIDD Guiton Dliii Fuels Ingredients Fof detailed brochuaCOc stamps/check oisi CAROLINA-TAFFINDER 8345 Delhi Road charleston Hgts. SC 29418 803-563-7169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O120 SEND $200 FOR COMPLETE CATALOG OF FINE KITS IKON NWST ox 566 Auburn WA 98071 206941-8248
Edition: Model Aviation - 1985/04
Page Numbers: 52, 53, 149, 150, 151, 152
Radio Control Electrics Bob Kopski TWOFERS time month gonna explore two topic areas first discussion comparison several large motors Theres comparatively little information readily available subject hope coverage will prove useful considering moving up power system size Basic Electricity Part 2 will pickup last months installment ended con tinuing short course aimed simplifying confusing science stuff Large motors Its no secret folks first try hand Electric comparatively small-size power systems makes lots sense because its lowest-cost way finding Out just much fun Electric can smaller systems far easiest charge theres nothing small about performance can provide either fact have maintained along small systems can provide about much performance large systems thats feel should no Electric competition classes based 'size' least now Nevertheless reasons con sider moving up larger power installa Handling motor brush/commutatOr heat L-R Unger 18s massive finned-alumi num heat sink Robbes large vents cooling air both air circulation around motor vital carrying off heat tions course models can larger some folks like Some feel better large machine poorer weather addition larger more-powerful Electrics will ground-handle much better though larger installations costly charging difficult some will find biggies lot funand fun course hobby anyway Lets take closer look several large motors lead photo shows six motors about same size Electric motor size~ confusing term because no established standard such gauged have own way dealing its simply categorization much power given product will handle Anyone whos following MAs Electric articles beginning September 1983 knows favor relat ing electrical power model parameters other way around depending upon primary interest user other words model thats big weighs much needs much elec trical power fly desired fashion duration performance determined battery size explained great detail series table included lists certain parameters statistics motors used presentation large motors existence have Anyway turns out six motors five pro peller combinations tested motor probably inappropriately included Its Astro ferrite 25 nothing wrong motorits just Three kinds large-motor prop adapters LR Unger uses collet-ilke arrangement wherein drive washer wrenching fiats has tapered Inner bore rides up tapered chuck prop tight ened Astro uses set screw hold hexsided prop nut Keller 50124 has set screw riding slotted flat armature shaft other five could easily handle power theyre bigger plan retest motor along some others nearly its equal future Mean results included information IN PUT POWER IN WATTS mu Motor ~ t t* g AVR10-1514-1814-lU17-2411-lB15-24 8000100 a9000140140121127126 C 0197181164166175165 11000266243217215226215 12000280286301285 12500344 13000373380 AVR9-1413-2011-1615-2311-1413-20 700099 7500120 8000145128121122126 8500176158 9000214189171177185171 9500251223 10000265233241256240 10500300 11000367318322321 AVR9-1210-1711-1414-229-1114-lU 600010891 6500135113 7000171142133143 7500216161162175187 8000214199197215198 8500237232237 9000318287281280 9500329329 10000392 AVR8-1210-1410-1213-IS7-1013-19 550010441 136 133116 6500181 146134131144 7000233 186165164181166 7500227203202203 8000248246247 8500294301 9000364 AVR7-109128-1012-186-811-15 45009980 500014011298112 .5500194148132129147134 6000195173166175 N6500216225 7000275285 7500343 wt oz 14 18% 13% 14% 12 15 data based single sample motor/prop believed cor rect AVR input voltage input power product voltage current amps Voltage varIed obtain desired rpm value Data reteais part prop its rpm set power level motor motors run about same efficIency over ranges shown use data table select approximate power watts desired model decide approximate size prop want use Example 250 watts large prop desired Look 116 g ro data Astro 40 cobalt Keller an~ger 18 liver power 8000 Examine AVR voltage number cells will required Astro needs about 12 volts Keller something less 19 volts Unger somewhere between same size amp-hr cells Astro would fly shortest time Keller longest wanted use Astro get longer flights switch 96 prop add couple cells bat tery example cieriy shows motors can same jobyet differ operating voitagelcurrent characteristics 52 Model Aviation up pressing radio noise electric motors L-R Astro has bypass capacitor between motor leads connector end Keller uses built-in capacitorsone brush motor housIng tween brushes Robbe U nger motors use add-on external capacitors Getting spring tension motor brushes L-R Astro uses conventional compression spring brush rides guide tube Easy replace screw-on cap Robbes large brushes use large coiled clock springs Now some details motors run benchstatic-tested using lab-type power supply instead batteries high-power supply easily-adjusted output voltage given motor/prop combination could run up over wide useful range power levels Its remote-sensing supply means voltage values given voltages right motor brushes data taken during several-hour period same day done air load test samples would same Remember prop does work moving air cooler warmer air moist/lessmoist air represent different burdens motor hence electrical power required given prop rpm Motors props merely devices convert stored energy batter ies moving air purposes motor comparison same props run motor power supply adjusted desired rpms motor voltage current recorded productpoweris given table various combinations props used varied diameter 8 12 one-inch steps 6-in pitch Top Elite Super M used throughout doesnt mean other sizes brands cant used its just make reasonable representative selection props drilled fit various prop adapters balanced keep test props aside used motor tests flown risk breakage assures data take various times same props although have no similar control over shop air As coincidence just due nature prop supply wound up using almost same prop sizes published December 1984 Ampere Flyer doing same job fact Unger 18 characterized issue ex actly same same serial number used Now dont know what prop brand used Europe surely dont have feel what test air like guess what raw data Continued page 149 five large motors used gathering data table LR Astro 25 ferrIte Astro 40 cobalt Leisure-supplied Keller 50124 cobalt Robbe 50/14 SE cobalt Unger 18 cobalt Average weight less 14% oz typical plane would weigh about 8 lb Motors shown list $75 over $150 Se e 0 C 0 ~4$\ 4e 4$ 04$ \- YORK ROAD TWAONIUM TIMONIUM RD EDEftICGROUNDS BALTIMORE / oS TIMONIUM RD EAST EXIT 16 OFF OF INTERSTATE 83 q4TO MD STATE FAIRGROUNDS TIMONIUM FAIR GROUNDS TIMONIUM MARYLAND FOR INFO CONTACT MARC DIRECTOR Dan Yarchin 6331 Red Cedar Place Baltimore Maryland 21209 301 358-8819 SPONSORED BY THE RADIO CONTROL MODELERS OF BALTIMORE April 1985 53 want try something different exciting both ends towline try aero towing dont have start off exotic mega-buck Scale bird either Dust off old floater rig simple tow release nose have tow bird want workhorse rather some sleek Pattern ship gents Munich using ships 60 90 cu displacements fifth- quarter-scale ships really want some fin challenge launching partner spotlanding contest Hes got make dead stick after might get old flying field back youre almost sure win free lunch him Back lathe January column mention made some pretty fine publications available wrong price SFVSF TechnicalAnthology goes $1250 $10 stated Have sent some money support USA F3B team Good lift Dan Pruss 131 E Pennington Ln Plainfleld IL 60544 RC Electrics/Kopski Continued page 53 quite close agreement published AFT lends lot credibility confidence own feelings about whats presented highly-detailed description Unger 18 can found December 1984 Ampere Flyer electrical data measured digital volt amp meters rpm read analog tach estimated accuracies 2% respec tively two electrical parameters accuracy plus resolution tach estimated ase absolute accuracies important relative results motors run over load power input ranges would personally use own planes As noted times before conservative approach Electric want motors batteries whatever run well last long help assure dont push anything Thus some motors may advertised capable running higher power levels generally hold operating conditions below maximum Also practical reasons usually dont bother testing much beyond 20 volts because Id rather fly cellsits too much trou ble charge such pack same sense usually wont test much beyond 20 amps because Id rather have some reasonable flight duration Besides such heavy currents tend reduce system effi ciencies rapidly due PR losses studying table youll notice motors tested same rpm limits same props general ly because either operating voltage current reached upper limit Signal Guard blocks random noise off-frequency signals can cause loss control air land RO models Signal Guard responds sig nals its own precisely tuned fre quency ignoring static noise craft itself Plus additional amplification allows control operators visual limit cared test Thus some motor large prop would tend draw high current relatively low applied voltage inverse might true another motor Among other things could due nature armature winding design some intended application motor See February 1985 MA Thus other parameter might limit first course condi tions some in-between prop sizes would permit both voltage current top out about same time thus producing highest possible power levels listed Finally some missing obviously desirable test points result oversight during hectic testing Sorry want spend time flying less time money repairing crashed model Signal Guard answer Call toll-free 1-800-468-8215 order Signal GuardTM major credit card send $150 check money order PO Box 30179 Portland OR 97230 Oregon call collect 503-257-0912 So does use informa tion select motor impor tant consideration particular appli cation example youre primarily interested long lazy sport flying choose motor/prop produces necessary power level relatively higher voltage lower currenta given bat tery will last longest other hand prefer highpower bursts short duration some competitive reason go other way around Select motor/prop uses fewest smallest cells lightest-weight pack will still meet current de mand desired short motor run time theres intermediate approach should appeal hotter sport April 1985 149 90 day warranty cted dealerships available fliera sort combination approach can choose motor/prop battery capable producing rather high power levels reasonable motor run time control system flight high-quality elec tronic speed control control feature allows pilot ease off power preserve battery charge hence extend flight time required pour juice some powerintensive maneuver called Whatever desired application enough data such com bined MAs earlier Electric how-to articles can assured achieving desired large-plane flightperformance goals As suggested earlier its feasible test motor possible prop cannot find just right combination motor prop operat ing power-level tables just use different prop Remember lowering pitch reduces power increasing does opposite Also feel free trim prop diameter in-between sizes Again reducing diameter reduces power vice versa sure balance props after such trim job fashion can select motor purchase varying props cell-count attain very wide range operating power performance levels summary motors characterized perform very well similarly will good job flying some larger plane fact within limits measurement accuracy prop suitability again clear its prop motor determines electrical power required battery exactly what Ive written several times before its reason no fear doing article As expected cobalts some what lighter efficient ferrites cost no differences big enough prevent consideration products What requirement very least cell count very smallest current drain Great several motor prop/battery combinations will job can choose motor fea tures like best photos illustrate some Consider differences cooling methods prop adaptors mounting requirements slight variations weight consider availability As far can see motors should work well long time right applica tion purpose find best motorI dont think such exists Its like trying find best car best tennis racket best HandLaunched Glider short unless dictated some very special application require ment its individual matter preference choice Basic Electricity Part Two Last months column presented some simple electrical terms voltage current showed some analogies water pressure flow Youll recall voltage likened depth water over head tank current circuit unlike water flow through aquaresistance represented pipe diameter Also column said electrical power motors product multiplication voltage current Specifically power watts equal volts times amps higher power work can done given time Lots elec trical power can fly given plane up higher rate climb less electrical power Further clear voltage requires cells battery current demand drains given battery quickly larger plane requires larger motor capable han dling higher voltage/currents needed produce higher power Lets back up little start out simply Suppose consider flashlight has battery lamp lamp really small resistance wire connected battery results current flow lamp load battery voltage times current flows power delivered lamp power produces heatthe small resistance wire ele ment gets extremely hot glows brightly similar though bigger example - For Foam Its Best Deal Best PEANUT SCALE MODEU Kits $895 ZEROMILES M-I8 PIETENPOLDRUINE PIPER cusCOUGAR ANDRESONGIPSY MOTH MUSTANGLACEY M-lOGANAGOBIE SPORT MODEU BABY ACE$849 ONE NITE 28$695 ONE NITE IS$695 STRINGLESS$495 PECK ROG$198 RADIO 3LIIdPS CONTROLLED II sad 13 FOOT LONGKITS OR READY TO FLY NOW IN THREE COLORS GRAY ORANGE YELLOW LOW PRICES CATALOG No 25 $150 PHONE 819 442-4636 619 489-8675 LA MESA CA 92041 Model Aviation LLL iii eacn ve Marina Del Rey UA ~i 1-624 FOAM WING CORES TOM FOAM CUTTING iiwd PRAIRIE BIRD T $598 Custom Cut i- iau 1u ruse IS OCEAN STATE AEROMODEL ENGINEERING$14995 21 Jeyc Dr ~ Dealer & Kit Weat Warwick RI 02893Manufacturers WS4 4018288813Inquiries Invited Coming Soon e F8F BearCat Modelers Choice GMP EPOXIES High Quality Model Construction Jr Kwik Set 6 Minute5 oz $595 Kwik Set 6 Minute10 Os $995 Giant Kwik Set 6 Minute16 os$1395 Half FastlOMinutelOoz$895 GMP AIRCRAFT INSTRUMENTS 80in31161/4318112$ 149 40 3/4 inch $149 EASY OFF PULLER proper tool removing drive washersand flywheels $ 795 Gas Model Products 8773 Russet Dr Cincinnati OH 45239 513 385-7398 out e8 dealer order Ante Poat add $150 electric clothes iron Power levels 1000 watts typical household irons takes lot power heat keep such implement hot light typical flashlight former much bigger job done power needed examples electrical power input resistive loads produces heat and/or light relationships elec trical terms involved given Ohms Law can expressed very simple arithmetic expression written three different ways 1 Voltage ent x resistance 2 Current age/Resistance 3 Resistance age/Current case two terms known third unknown may found easily example lets say flashlight battery consisted two cells having cell chemistry produces 15 volts cell terminals cells properly installed typical flashlight con nected series total voltage sum two three volts Now lets say flashlight lamp has resistance 12 ohms typical value informa tion current flowing lamp can found formula 2 /12 current amps V voltage R resistance ohms Suppose now werent able see light lamp knew some current being taken battery some kind load might know because connected multimeters pictured last month such fashion battery current output read same lamp above current meter would read amp might recon nect multimeter read voltage scale use read battery voltage would say 3 volts could easily determine circuit load resistance formula 3 R 3/1/4 e divided one-fourth hms Cash Check Stamps 32 Page Tabloid size illustrated DISCOUNT Catalog Sent 1st Class Mail COMET COX FLYLINE FOX GOLDBERG GUILLOWS JETCO K&fl PACTRA PECK POLYMER PERFECT SIG- STERLiNG SULLIVAN TOP FLITE & OTHERS PENN VALLEY HOBBY CENTER 917 1 Main 3t Lana1sPa 19146 21Sf 865 t268 3680010 SPARROWHAWK 1/32 SCALE PLASTIC MODEL KIT AJS US Navy Sparrowhawks operated two dirigibles aircraft carrier during 1930s among colorful aircraft aviations Golden Age KIT FEATURES U Decals permit finishing model six different Sparrowhawks Two types wheels hard flexible tires U Monofilament rigging U Detailed interior Send $1 complete catalog kits accessories Dept MA WILLIAMS BROTHERS INC 181 PAWNEE ST SAN MARCOS CA 92069 Just exactly use multimeter simple measurements will covered future column now gonna move learn about electrical parameterpower stated above power product voltage current Thus formula relationship Power age x Current P power P expressed watts Look above formulas use little imagination can see power can related circuit load resistance example formula 1 know V Suppose use equality stuff left side equals sign exactly same stuff right side equals sign can used stead other place V formula power Accepted arithmetic practice allows done have P I P IxIxR identical P red PR x needed Similarly should clear P V x V/R Now weve written formulas lets show can put use calculating power used light bulb flashlight Although going three different ways results going same time First lets use volts amps P 3 x att Next well use current resistance P x 12 x 12 = Y4 watt Finally well use voltage resistance P 2 3/ watt April 1985 151 FIBERGLASS & FOAM V CONSTRUCTION FAI & AMA PATtERN 60-61 ENGINE #84 SPAN 704 sq AREA WEIGHT 8 LBS DEPENDING ON EQUIP BASIC KIT$10795 DELUXE KITS15995 Call 10U AM IC 9101 PM Mail-Sal 1115A & MASIER CARD L S L MODEL DEALER & 01ST6000 BCPRODUCTS INQUIRIES INVITEDf513 341-0012 7342 6dg COiliI DnIonlI 0140 46247 AMERICAN JUNIOR .404 Interceptor new A-P404 foldIng wing interreptor lao refresher count Have Fun II youve never Ilown youll fhrillaofhewingsunloldiotosoarlogsi5htllyoUhavC flown heloreif will come back Now can oson ol GREATAMERICAN JUNIOR CLOSSICSYonII love It.and ao will everyone else 404 BuIlder lOt$395 404 AIU595 404 RTF795 74 Glider195 Boa 548 743-in-l Pak495Oregon City 0R97045 See year Oubby Oealer c stock rely order 11001 order direct Poet auc aud 0odliOu Chaeuee 1300 foe first model plus 1091 oddrtluOal RCFS II RADIO CONTROLLED FLIGHT SIMULATOR John Kallend FOR APPLE 11 lie GREAT AS TRAINING AID FOR BEGINNER OR -PPm PIAJY AEROBATIC INCLUDING SPINS AND SNAP ROUS CONFIGURE FOR LARGE VARIETY OF MODELS FROM TRAINERS TO HOT AERORATIC MODELS USE WITH DAVE BROWN PRODUCTS DUAL JOY STICK TRANSMrITEW FOR THE MOST ACCURATE SIMULATION OF R/C PLYING CAN BE USED WITH ANY APPLE COMPATABLE JOYSTICK IT EVEN HAS DUAL RATE CONTROL SENSmVITY NOSE BEGUIREI APPLE II PUll 48K sInI E II WITH BIlE DRIVE AND AR APPLE COMPATARLE JOY 551CR OR DAVE BROWN PRODUCIS DUAl JOYSTICIC TEANIMmEB DAVE BROWN PRODUCTS Notice earlier discussion using hundreds watts turn large propellers fast takes less watt light flashlight So whats have motors batteries Electrics hangs together friends Stay tuned youll have lot insight Electrics work tune out maybe thisll help win some future contestsif meantime please direct ques tions SASE author Happy Electric landings Bob Kopski 25 West End Dr Lansdale PA 19446 RC Old-Timers/Mathews Continued page 55 Its glue Recently laying some laminated outlines down flashed through mind way Hank Struck others should have Available Now Commodore lLZ4\-\~4 V 4860 LAYHIGH HAMILTON OHIO 45013 done designs dawned us bent wire tubing original ly used Apache Cabruler forth werent done laminated balsa simply because nitrocellulose Ambroid Comet etc glue available adhesive such simple thing spray three four layers /16 / whatever dilute ammonia water coat layers aliphatic resin glue Sig Bond etc pull around form pins Hank likely now uses technique himself try Ambroid some time Weve seen TV commercials ask Wheres beef time another modelers must have asked Wheres CG weve built kit manufacturer has done work us shows us plans center gravity CG supposed fact better approximately shows us its supposed model going fly well crunch comes weve got latest masterpiece completed ready flight seldom happens CG has come out money want new plane live weve got add some ballast plane make CG move its sup posed Sure can use age-old cut-and-try method may too time-consuming difficult some cases What neat solution problem published recent edition news letter Lehigh Valley PA RC Club Tom Bilheimer editor order use method described youll need accurate scalepreferably graduated ounces Youll also need accurate ruler yardstick might better scheme described makes use princi ple balancing moments plans show location CG Lets say supposed 375 behind leading edge LE wing Since may convenient meas ure different fixed spot model lets use tip spinner end crankshaft Lets seethe CG should 1075 point Hmmm After finding marking balance point new model find CG actually 10375 reference point means plane nose-heavy weve got add some weight tail Wed like add little weight possible well put near tail possible Measuring plane find can add some weight inconspicuously point 31 inches reference point much weight find out answer question well have use little arithmetic multi plication division some algebra will multiply distance reference point nose location actual CG weight model add product distance reference point place can add ballast times unknown added weight divide sum models weight unknown added weight Well set 152 Model Aviation Complete DIN Line ofFx~ - Quality Finishing Products DIN Pto FESSIONALS CHOICE Kin Craft Mig 14323 TwIn Ridge Court Ashland Kentucky 41101 606 928-4763 ASK FOR US AT TOUR FAVORITE HOllY SHOP GONTIOLINI TillS PROFILECOMBA 7RA T WIDE & NARROW WEDGE 75 -- 6 Capacities INIFLOW & STIIDD Guiton Dliii Fuels Ingredients Fof detailed brochuaCOc stamps/check oisi CAROLINA-TAFFINDER 8345 Delhi Road charleston Hgts. SC 29418 803-563-7169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O120 SEND $200 FOR COMPLETE CATALOG OF FINE KITS IKON NWST ox 566 Auburn WA 98071 206941-8248
Edition: Model Aviation - 1985/04
Page Numbers: 52, 53, 149, 150, 151, 152
Radio Control Electrics Bob Kopski TWOFERS time month gonna explore two topic areas first discussion comparison several large motors Theres comparatively little information readily available subject hope coverage will prove useful considering moving up power system size Basic Electricity Part 2 will pickup last months installment ended con tinuing short course aimed simplifying confusing science stuff Large motors Its no secret folks first try hand Electric comparatively small-size power systems makes lots sense because its lowest-cost way finding Out just much fun Electric can smaller systems far easiest charge theres nothing small about performance can provide either fact have maintained along small systems can provide about much performance large systems thats feel should no Electric competition classes based 'size' least now Nevertheless reasons con sider moving up larger power installa Handling motor brush/commutatOr heat L-R Unger 18s massive finned-alumi num heat sink Robbes large vents cooling air both air circulation around motor vital carrying off heat tions course models can larger some folks like Some feel better large machine poorer weather addition larger more-powerful Electrics will ground-handle much better though larger installations costly charging difficult some will find biggies lot funand fun course hobby anyway Lets take closer look several large motors lead photo shows six motors about same size Electric motor size~ confusing term because no established standard such gauged have own way dealing its simply categorization much power given product will handle Anyone whos following MAs Electric articles beginning September 1983 knows favor relat ing electrical power model parameters other way around depending upon primary interest user other words model thats big weighs much needs much elec trical power fly desired fashion duration performance determined battery size explained great detail series table included lists certain parameters statistics motors used presentation large motors existence have Anyway turns out six motors five pro peller combinations tested motor probably inappropriately included Its Astro ferrite 25 nothing wrong motorits just Three kinds large-motor prop adapters LR Unger uses collet-ilke arrangement wherein drive washer wrenching fiats has tapered Inner bore rides up tapered chuck prop tight ened Astro uses set screw hold hexsided prop nut Keller 50124 has set screw riding slotted flat armature shaft other five could easily handle power theyre bigger plan retest motor along some others nearly its equal future Mean results included information IN PUT POWER IN WATTS mu Motor ~ t t* g AVR10-1514-1814-lU17-2411-lB15-24 8000100 a9000140140121127126 C 0197181164166175165 11000266243217215226215 12000280286301285 12500344 13000373380 AVR9-1413-2011-1615-2311-1413-20 700099 7500120 8000145128121122126 8500176158 9000214189171177185171 9500251223 10000265233241256240 10500300 11000367318322321 AVR9-1210-1711-1414-229-1114-lU 600010891 6500135113 7000171142133143 7500216161162175187 8000214199197215198 8500237232237 9000318287281280 9500329329 10000392 AVR8-1210-1410-1213-IS7-1013-19 550010441 136 133116 6500181 146134131144 7000233 186165164181166 7500227203202203 8000248246247 8500294301 9000364 AVR7-109128-1012-186-811-15 45009980 500014011298112 .5500194148132129147134 6000195173166175 N6500216225 7000275285 7500343 wt oz 14 18% 13% 14% 12 15 data based single sample motor/prop believed cor rect AVR input voltage input power product voltage current amps Voltage varIed obtain desired rpm value Data reteais part prop its rpm set power level motor motors run about same efficIency over ranges shown use data table select approximate power watts desired model decide approximate size prop want use Example 250 watts large prop desired Look 116 g ro data Astro 40 cobalt Keller an~ger 18 liver power 8000 Examine AVR voltage number cells will required Astro needs about 12 volts Keller something less 19 volts Unger somewhere between same size amp-hr cells Astro would fly shortest time Keller longest wanted use Astro get longer flights switch 96 prop add couple cells bat tery example cieriy shows motors can same jobyet differ operating voitagelcurrent characteristics 52 Model Aviation up pressing radio noise electric motors L-R Astro has bypass capacitor between motor leads connector end Keller uses built-in capacitorsone brush motor housIng tween brushes Robbe U nger motors use add-on external capacitors Getting spring tension motor brushes L-R Astro uses conventional compression spring brush rides guide tube Easy replace screw-on cap Robbes large brushes use large coiled clock springs Now some details motors run benchstatic-tested using lab-type power supply instead batteries high-power supply easily-adjusted output voltage given motor/prop combination could run up over wide useful range power levels Its remote-sensing supply means voltage values given voltages right motor brushes data taken during several-hour period same day done air load test samples would same Remember prop does work moving air cooler warmer air moist/lessmoist air represent different burdens motor hence electrical power required given prop rpm Motors props merely devices convert stored energy batter ies moving air purposes motor comparison same props run motor power supply adjusted desired rpms motor voltage current recorded productpoweris given table various combinations props used varied diameter 8 12 one-inch steps 6-in pitch Top Elite Super M used throughout doesnt mean other sizes brands cant used its just make reasonable representative selection props drilled fit various prop adapters balanced keep test props aside used motor tests flown risk breakage assures data take various times same props although have no similar control over shop air As coincidence just due nature prop supply wound up using almost same prop sizes published December 1984 Ampere Flyer doing same job fact Unger 18 characterized issue ex actly same same serial number used Now dont know what prop brand used Europe surely dont have feel what test air like guess what raw data Continued page 149 five large motors used gathering data table LR Astro 25 ferrIte Astro 40 cobalt Leisure-supplied Keller 50124 cobalt Robbe 50/14 SE cobalt Unger 18 cobalt Average weight less 14% oz typical plane would weigh about 8 lb Motors shown list $75 over $150 Se e 0 C 0 ~4$\ 4e 4$ 04$ \- YORK ROAD TWAONIUM TIMONIUM RD EDEftICGROUNDS BALTIMORE / oS TIMONIUM RD EAST EXIT 16 OFF OF INTERSTATE 83 q4TO MD STATE FAIRGROUNDS TIMONIUM FAIR GROUNDS TIMONIUM MARYLAND FOR INFO CONTACT MARC DIRECTOR Dan Yarchin 6331 Red Cedar Place Baltimore Maryland 21209 301 358-8819 SPONSORED BY THE RADIO CONTROL MODELERS OF BALTIMORE April 1985 53 want try something different exciting both ends towline try aero towing dont have start off exotic mega-buck Scale bird either Dust off old floater rig simple tow release nose have tow bird want workhorse rather some sleek Pattern ship gents Munich using ships 60 90 cu displacements fifth- quarter-scale ships really want some fin challenge launching partner spotlanding contest Hes got make dead stick after might get old flying field back youre almost sure win free lunch him Back lathe January column mention made some pretty fine publications available wrong price SFVSF TechnicalAnthology goes $1250 $10 stated Have sent some money support USA F3B team Good lift Dan Pruss 131 E Pennington Ln Plainfleld IL 60544 RC Electrics/Kopski Continued page 53 quite close agreement published AFT lends lot credibility confidence own feelings about whats presented highly-detailed description Unger 18 can found December 1984 Ampere Flyer electrical data measured digital volt amp meters rpm read analog tach estimated accuracies 2% respec tively two electrical parameters accuracy plus resolution tach estimated ase absolute accuracies important relative results motors run over load power input ranges would personally use own planes As noted times before conservative approach Electric want motors batteries whatever run well last long help assure dont push anything Thus some motors may advertised capable running higher power levels generally hold operating conditions below maximum Also practical reasons usually dont bother testing much beyond 20 volts because Id rather fly cellsits too much trou ble charge such pack same sense usually wont test much beyond 20 amps because Id rather have some reasonable flight duration Besides such heavy currents tend reduce system effi ciencies rapidly due PR losses studying table youll notice motors tested same rpm limits same props general ly because either operating voltage current reached upper limit Signal Guard blocks random noise off-frequency signals can cause loss control air land RO models Signal Guard responds sig nals its own precisely tuned fre quency ignoring static noise craft itself Plus additional amplification allows control operators visual limit cared test Thus some motor large prop would tend draw high current relatively low applied voltage inverse might true another motor Among other things could due nature armature winding design some intended application motor See February 1985 MA Thus other parameter might limit first course condi tions some in-between prop sizes would permit both voltage current top out about same time thus producing highest possible power levels listed Finally some missing obviously desirable test points result oversight during hectic testing Sorry want spend time flying less time money repairing crashed model Signal Guard answer Call toll-free 1-800-468-8215 order Signal GuardTM major credit card send $150 check money order PO Box 30179 Portland OR 97230 Oregon call collect 503-257-0912 So does use informa tion select motor impor tant consideration particular appli cation example youre primarily interested long lazy sport flying choose motor/prop produces necessary power level relatively higher voltage lower currenta given bat tery will last longest other hand prefer highpower bursts short duration some competitive reason go other way around Select motor/prop uses fewest smallest cells lightest-weight pack will still meet current de mand desired short motor run time theres intermediate approach should appeal hotter sport April 1985 149 90 day warranty cted dealerships available fliera sort combination approach can choose motor/prop battery capable producing rather high power levels reasonable motor run time control system flight high-quality elec tronic speed control control feature allows pilot ease off power preserve battery charge hence extend flight time required pour juice some powerintensive maneuver called Whatever desired application enough data such com bined MAs earlier Electric how-to articles can assured achieving desired large-plane flightperformance goals As suggested earlier its feasible test motor possible prop cannot find just right combination motor prop operat ing power-level tables just use different prop Remember lowering pitch reduces power increasing does opposite Also feel free trim prop diameter in-between sizes Again reducing diameter reduces power vice versa sure balance props after such trim job fashion can select motor purchase varying props cell-count attain very wide range operating power performance levels summary motors characterized perform very well similarly will good job flying some larger plane fact within limits measurement accuracy prop suitability again clear its prop motor determines electrical power required battery exactly what Ive written several times before its reason no fear doing article As expected cobalts some what lighter efficient ferrites cost no differences big enough prevent consideration products What requirement very least cell count very smallest current drain Great several motor prop/battery combinations will job can choose motor fea tures like best photos illustrate some Consider differences cooling methods prop adaptors mounting requirements slight variations weight consider availability As far can see motors should work well long time right applica tion purpose find best motorI dont think such exists Its like trying find best car best tennis racket best HandLaunched Glider short unless dictated some very special application require ment its individual matter preference choice Basic Electricity Part Two Last months column presented some simple electrical terms voltage current showed some analogies water pressure flow Youll recall voltage likened depth water over head tank current circuit unlike water flow through aquaresistance represented pipe diameter Also column said electrical power motors product multiplication voltage current Specifically power watts equal volts times amps higher power work can done given time Lots elec trical power can fly given plane up higher rate climb less electrical power Further clear voltage requires cells battery current demand drains given battery quickly larger plane requires larger motor capable han dling higher voltage/currents needed produce higher power Lets back up little start out simply Suppose consider flashlight has battery lamp lamp really small resistance wire connected battery results current flow lamp load battery voltage times current flows power delivered lamp power produces heatthe small resistance wire ele ment gets extremely hot glows brightly similar though bigger example - For Foam Its Best Deal Best PEANUT SCALE MODEU Kits $895 ZEROMILES M-I8 PIETENPOLDRUINE PIPER cusCOUGAR ANDRESONGIPSY MOTH MUSTANGLACEY M-lOGANAGOBIE SPORT MODEU BABY ACE$849 ONE NITE 28$695 ONE NITE IS$695 STRINGLESS$495 PECK ROG$198 RADIO 3LIIdPS CONTROLLED II sad 13 FOOT LONGKITS OR READY TO FLY NOW IN THREE COLORS GRAY ORANGE YELLOW LOW PRICES CATALOG No 25 $150 PHONE 819 442-4636 619 489-8675 LA MESA CA 92041 Model Aviation LLL iii eacn ve Marina Del Rey UA ~i 1-624 FOAM WING CORES TOM FOAM CUTTING iiwd PRAIRIE BIRD T $598 Custom Cut i- iau 1u ruse IS OCEAN STATE AEROMODEL ENGINEERING$14995 21 Jeyc Dr ~ Dealer & Kit Weat Warwick RI 02893Manufacturers WS4 4018288813Inquiries Invited Coming Soon e F8F BearCat Modelers Choice GMP EPOXIES High Quality Model Construction Jr Kwik Set 6 Minute5 oz $595 Kwik Set 6 Minute10 Os $995 Giant Kwik Set 6 Minute16 os$1395 Half FastlOMinutelOoz$895 GMP AIRCRAFT INSTRUMENTS 80in31161/4318112$ 149 40 3/4 inch $149 EASY OFF PULLER proper tool removing drive washersand flywheels $ 795 Gas Model Products 8773 Russet Dr Cincinnati OH 45239 513 385-7398 out e8 dealer order Ante Poat add $150 electric clothes iron Power levels 1000 watts typical household irons takes lot power heat keep such implement hot light typical flashlight former much bigger job done power needed examples electrical power input resistive loads produces heat and/or light relationships elec trical terms involved given Ohms Law can expressed very simple arithmetic expression written three different ways 1 Voltage ent x resistance 2 Current age/Resistance 3 Resistance age/Current case two terms known third unknown may found easily example lets say flashlight battery consisted two cells having cell chemistry produces 15 volts cell terminals cells properly installed typical flashlight con nected series total voltage sum two three volts Now lets say flashlight lamp has resistance 12 ohms typical value informa tion current flowing lamp can found formula 2 /12 current amps V voltage R resistance ohms Suppose now werent able see light lamp knew some current being taken battery some kind load might know because connected multimeters pictured last month such fashion battery current output read same lamp above current meter would read amp might recon nect multimeter read voltage scale use read battery voltage would say 3 volts could easily determine circuit load resistance formula 3 R 3/1/4 e divided one-fourth hms Cash Check Stamps 32 Page Tabloid size illustrated DISCOUNT Catalog Sent 1st Class Mail COMET COX FLYLINE FOX GOLDBERG GUILLOWS JETCO K&fl PACTRA PECK POLYMER PERFECT SIG- STERLiNG SULLIVAN TOP FLITE & OTHERS PENN VALLEY HOBBY CENTER 917 1 Main 3t Lana1sPa 19146 21Sf 865 t268 3680010 SPARROWHAWK 1/32 SCALE PLASTIC MODEL KIT AJS US Navy Sparrowhawks operated two dirigibles aircraft carrier during 1930s among colorful aircraft aviations Golden Age KIT FEATURES U Decals permit finishing model six different Sparrowhawks Two types wheels hard flexible tires U Monofilament rigging U Detailed interior Send $1 complete catalog kits accessories Dept MA WILLIAMS BROTHERS INC 181 PAWNEE ST SAN MARCOS CA 92069 Just exactly use multimeter simple measurements will covered future column now gonna move learn about electrical parameterpower stated above power product voltage current Thus formula relationship Power age x Current P power P expressed watts Look above formulas use little imagination can see power can related circuit load resistance example formula 1 know V Suppose use equality stuff left side equals sign exactly same stuff right side equals sign can used stead other place V formula power Accepted arithmetic practice allows done have P I P IxIxR identical P red PR x needed Similarly should clear P V x V/R Now weve written formulas lets show can put use calculating power used light bulb flashlight Although going three different ways results going same time First lets use volts amps P 3 x att Next well use current resistance P x 12 x 12 = Y4 watt Finally well use voltage resistance P 2 3/ watt April 1985 151 FIBERGLASS & FOAM V CONSTRUCTION FAI & AMA PATtERN 60-61 ENGINE #84 SPAN 704 sq AREA WEIGHT 8 LBS DEPENDING ON EQUIP BASIC KIT$10795 DELUXE KITS15995 Call 10U AM IC 9101 PM Mail-Sal 1115A & MASIER CARD L S L MODEL DEALER & 01ST6000 BCPRODUCTS INQUIRIES INVITEDf513 341-0012 7342 6dg COiliI DnIonlI 0140 46247 AMERICAN JUNIOR .404 Interceptor new A-P404 foldIng wing interreptor lao refresher count Have Fun II youve never Ilown youll fhrillaofhewingsunloldiotosoarlogsi5htllyoUhavC flown heloreif will come back Now can oson ol GREATAMERICAN JUNIOR CLOSSICSYonII love It.and ao will everyone else 404 BuIlder lOt$395 404 AIU595 404 RTF795 74 Glider195 Boa 548 743-in-l Pak495Oregon City 0R97045 See year Oubby Oealer c stock rely order 11001 order direct Poet auc aud 0odliOu Chaeuee 1300 foe first model plus 1091 oddrtluOal RCFS II RADIO CONTROLLED FLIGHT SIMULATOR John Kallend FOR APPLE 11 lie GREAT AS TRAINING AID FOR BEGINNER OR -PPm PIAJY AEROBATIC INCLUDING SPINS AND SNAP ROUS CONFIGURE FOR LARGE VARIETY OF MODELS FROM TRAINERS TO HOT AERORATIC MODELS USE WITH DAVE BROWN PRODUCTS DUAL JOY STICK TRANSMrITEW FOR THE MOST ACCURATE SIMULATION OF R/C PLYING CAN BE USED WITH ANY APPLE COMPATABLE JOYSTICK IT EVEN HAS DUAL RATE CONTROL SENSmVITY NOSE BEGUIREI APPLE II PUll 48K sInI E II WITH BIlE DRIVE AND AR APPLE COMPATARLE JOY 551CR OR DAVE BROWN PRODUCIS DUAl JOYSTICIC TEANIMmEB DAVE BROWN PRODUCTS Notice earlier discussion using hundreds watts turn large propellers fast takes less watt light flashlight So whats have motors batteries Electrics hangs together friends Stay tuned youll have lot insight Electrics work tune out maybe thisll help win some future contestsif meantime please direct ques tions SASE author Happy Electric landings Bob Kopski 25 West End Dr Lansdale PA 19446 RC Old-Timers/Mathews Continued page 55 Its glue Recently laying some laminated outlines down flashed through mind way Hank Struck others should have Available Now Commodore lLZ4\-\~4 V 4860 LAYHIGH HAMILTON OHIO 45013 done designs dawned us bent wire tubing original ly used Apache Cabruler forth werent done laminated balsa simply because nitrocellulose Ambroid Comet etc glue available adhesive such simple thing spray three four layers /16 / whatever dilute ammonia water coat layers aliphatic resin glue Sig Bond etc pull around form pins Hank likely now uses technique himself try Ambroid some time Weve seen TV commercials ask Wheres beef time another modelers must have asked Wheres CG weve built kit manufacturer has done work us shows us plans center gravity CG supposed fact better approximately shows us its supposed model going fly well crunch comes weve got latest masterpiece completed ready flight seldom happens CG has come out money want new plane live weve got add some ballast plane make CG move its sup posed Sure can use age-old cut-and-try method may too time-consuming difficult some cases What neat solution problem published recent edition news letter Lehigh Valley PA RC Club Tom Bilheimer editor order use method described youll need accurate scalepreferably graduated ounces Youll also need accurate ruler yardstick might better scheme described makes use princi ple balancing moments plans show location CG Lets say supposed 375 behind leading edge LE wing Since may convenient meas ure different fixed spot model lets use tip spinner end crankshaft Lets seethe CG should 1075 point Hmmm After finding marking balance point new model find CG actually 10375 reference point means plane nose-heavy weve got add some weight tail Wed like add little weight possible well put near tail possible Measuring plane find can add some weight inconspicuously point 31 inches reference point much weight find out answer question well have use little arithmetic multi plication division some algebra will multiply distance reference point nose location actual CG weight model add product distance reference point place can add ballast times unknown added weight divide sum models weight unknown added weight Well set 152 Model Aviation Complete DIN Line ofFx~ - Quality Finishing Products DIN Pto FESSIONALS CHOICE Kin Craft Mig 14323 TwIn Ridge Court Ashland Kentucky 41101 606 928-4763 ASK FOR US AT TOUR FAVORITE HOllY SHOP GONTIOLINI TillS PROFILECOMBA 7RA T WIDE & NARROW WEDGE 75 -- 6 Capacities INIFLOW & STIIDD Guiton Dliii Fuels Ingredients Fof detailed brochuaCOc stamps/check oisi CAROLINA-TAFFINDER 8345 Delhi Road charleston Hgts. SC 29418 803-563-7169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O120 SEND $200 FOR COMPLETE CATALOG OF FINE KITS IKON NWST ox 566 Auburn WA 98071 206941-8248
Edition: Model Aviation - 1985/04
Page Numbers: 52, 53, 149, 150, 151, 152
Radio Control Electrics Bob Kopski TWOFERS time month gonna explore two topic areas first discussion comparison several large motors Theres comparatively little information readily available subject hope coverage will prove useful considering moving up power system size Basic Electricity Part 2 will pickup last months installment ended con tinuing short course aimed simplifying confusing science stuff Large motors Its no secret folks first try hand Electric comparatively small-size power systems makes lots sense because its lowest-cost way finding Out just much fun Electric can smaller systems far easiest charge theres nothing small about performance can provide either fact have maintained along small systems can provide about much performance large systems thats feel should no Electric competition classes based 'size' least now Nevertheless reasons con sider moving up larger power installa Handling motor brush/commutatOr heat L-R Unger 18s massive finned-alumi num heat sink Robbes large vents cooling air both air circulation around motor vital carrying off heat tions course models can larger some folks like Some feel better large machine poorer weather addition larger more-powerful Electrics will ground-handle much better though larger installations costly charging difficult some will find biggies lot funand fun course hobby anyway Lets take closer look several large motors lead photo shows six motors about same size Electric motor size~ confusing term because no established standard such gauged have own way dealing its simply categorization much power given product will handle Anyone whos following MAs Electric articles beginning September 1983 knows favor relat ing electrical power model parameters other way around depending upon primary interest user other words model thats big weighs much needs much elec trical power fly desired fashion duration performance determined battery size explained great detail series table included lists certain parameters statistics motors used presentation large motors existence have Anyway turns out six motors five pro peller combinations tested motor probably inappropriately included Its Astro ferrite 25 nothing wrong motorits just Three kinds large-motor prop adapters LR Unger uses collet-ilke arrangement wherein drive washer wrenching fiats has tapered Inner bore rides up tapered chuck prop tight ened Astro uses set screw hold hexsided prop nut Keller 50124 has set screw riding slotted flat armature shaft other five could easily handle power theyre bigger plan retest motor along some others nearly its equal future Mean results included information IN PUT POWER IN WATTS mu Motor ~ t t* g AVR10-1514-1814-lU17-2411-lB15-24 8000100 a9000140140121127126 C 0197181164166175165 11000266243217215226215 12000280286301285 12500344 13000373380 AVR9-1413-2011-1615-2311-1413-20 700099 7500120 8000145128121122126 8500176158 9000214189171177185171 9500251223 10000265233241256240 10500300 11000367318322321 AVR9-1210-1711-1414-229-1114-lU 600010891 6500135113 7000171142133143 7500216161162175187 8000214199197215198 8500237232237 9000318287281280 9500329329 10000392 AVR8-1210-1410-1213-IS7-1013-19 550010441 136 133116 6500181 146134131144 7000233 186165164181166 7500227203202203 8000248246247 8500294301 9000364 AVR7-109128-1012-186-811-15 45009980 500014011298112 .5500194148132129147134 6000195173166175 N6500216225 7000275285 7500343 wt oz 14 18% 13% 14% 12 15 data based single sample motor/prop believed cor rect AVR input voltage input power product voltage current amps Voltage varIed obtain desired rpm value Data reteais part prop its rpm set power level motor motors run about same efficIency over ranges shown use data table select approximate power watts desired model decide approximate size prop want use Example 250 watts large prop desired Look 116 g ro data Astro 40 cobalt Keller an~ger 18 liver power 8000 Examine AVR voltage number cells will required Astro needs about 12 volts Keller something less 19 volts Unger somewhere between same size amp-hr cells Astro would fly shortest time Keller longest wanted use Astro get longer flights switch 96 prop add couple cells bat tery example cieriy shows motors can same jobyet differ operating voitagelcurrent characteristics 52 Model Aviation up pressing radio noise electric motors L-R Astro has bypass capacitor between motor leads connector end Keller uses built-in capacitorsone brush motor housIng tween brushes Robbe U nger motors use add-on external capacitors Getting spring tension motor brushes L-R Astro uses conventional compression spring brush rides guide tube Easy replace screw-on cap Robbes large brushes use large coiled clock springs Now some details motors run benchstatic-tested using lab-type power supply instead batteries high-power supply easily-adjusted output voltage given motor/prop combination could run up over wide useful range power levels Its remote-sensing supply means voltage values given voltages right motor brushes data taken during several-hour period same day done air load test samples would same Remember prop does work moving air cooler warmer air moist/lessmoist air represent different burdens motor hence electrical power required given prop rpm Motors props merely devices convert stored energy batter ies moving air purposes motor comparison same props run motor power supply adjusted desired rpms motor voltage current recorded productpoweris given table various combinations props used varied diameter 8 12 one-inch steps 6-in pitch Top Elite Super M used throughout doesnt mean other sizes brands cant used its just make reasonable representative selection props drilled fit various prop adapters balanced keep test props aside used motor tests flown risk breakage assures data take various times same props although have no similar control over shop air As coincidence just due nature prop supply wound up using almost same prop sizes published December 1984 Ampere Flyer doing same job fact Unger 18 characterized issue ex actly same same serial number used Now dont know what prop brand used Europe surely dont have feel what test air like guess what raw data Continued page 149 five large motors used gathering data table LR Astro 25 ferrIte Astro 40 cobalt Leisure-supplied Keller 50124 cobalt Robbe 50/14 SE cobalt Unger 18 cobalt Average weight less 14% oz typical plane would weigh about 8 lb Motors shown list $75 over $150 Se e 0 C 0 ~4$\ 4e 4$ 04$ \- YORK ROAD TWAONIUM TIMONIUM RD EDEftICGROUNDS BALTIMORE / oS TIMONIUM RD EAST EXIT 16 OFF OF INTERSTATE 83 q4TO MD STATE FAIRGROUNDS TIMONIUM FAIR GROUNDS TIMONIUM MARYLAND FOR INFO CONTACT MARC DIRECTOR Dan Yarchin 6331 Red Cedar Place Baltimore Maryland 21209 301 358-8819 SPONSORED BY THE RADIO CONTROL MODELERS OF BALTIMORE April 1985 53 want try something different exciting both ends towline try aero towing dont have start off exotic mega-buck Scale bird either Dust off old floater rig simple tow release nose have tow bird want workhorse rather some sleek Pattern ship gents Munich using ships 60 90 cu displacements fifth- quarter-scale ships really want some fin challenge launching partner spotlanding contest Hes got make dead stick after might get old flying field back youre almost sure win free lunch him Back lathe January column mention made some pretty fine publications available wrong price SFVSF TechnicalAnthology goes $1250 $10 stated Have sent some money support USA F3B team Good lift Dan Pruss 131 E Pennington Ln Plainfleld IL 60544 RC Electrics/Kopski Continued page 53 quite close agreement published AFT lends lot credibility confidence own feelings about whats presented highly-detailed description Unger 18 can found December 1984 Ampere Flyer electrical data measured digital volt amp meters rpm read analog tach estimated accuracies 2% respec tively two electrical parameters accuracy plus resolution tach estimated ase absolute accuracies important relative results motors run over load power input ranges would personally use own planes As noted times before conservative approach Electric want motors batteries whatever run well last long help assure dont push anything Thus some motors may advertised capable running higher power levels generally hold operating conditions below maximum Also practical reasons usually dont bother testing much beyond 20 volts because Id rather fly cellsits too much trou ble charge such pack same sense usually wont test much beyond 20 amps because Id rather have some reasonable flight duration Besides such heavy currents tend reduce system effi ciencies rapidly due PR losses studying table youll notice motors tested same rpm limits same props general ly because either operating voltage current reached upper limit Signal Guard blocks random noise off-frequency signals can cause loss control air land RO models Signal Guard responds sig nals its own precisely tuned fre quency ignoring static noise craft itself Plus additional amplification allows control operators visual limit cared test Thus some motor large prop would tend draw high current relatively low applied voltage inverse might true another motor Among other things could due nature armature winding design some intended application motor See February 1985 MA Thus other parameter might limit first course condi tions some in-between prop sizes would permit both voltage current top out about same time thus producing highest possible power levels listed Finally some missing obviously desirable test points result oversight during hectic testing Sorry want spend time flying less time money repairing crashed model Signal Guard answer Call toll-free 1-800-468-8215 order Signal GuardTM major credit card send $150 check money order PO Box 30179 Portland OR 97230 Oregon call collect 503-257-0912 So does use informa tion select motor impor tant consideration particular appli cation example youre primarily interested long lazy sport flying choose motor/prop produces necessary power level relatively higher voltage lower currenta given bat tery will last longest other hand prefer highpower bursts short duration some competitive reason go other way around Select motor/prop uses fewest smallest cells lightest-weight pack will still meet current de mand desired short motor run time theres intermediate approach should appeal hotter sport April 1985 149 90 day warranty cted dealerships available fliera sort combination approach can choose motor/prop battery capable producing rather high power levels reasonable motor run time control system flight high-quality elec tronic speed control control feature allows pilot ease off power preserve battery charge hence extend flight time required pour juice some powerintensive maneuver called Whatever desired application enough data such com bined MAs earlier Electric how-to articles can assured achieving desired large-plane flightperformance goals As suggested earlier its feasible test motor possible prop cannot find just right combination motor prop operat ing power-level tables just use different prop Remember lowering pitch reduces power increasing does opposite Also feel free trim prop diameter in-between sizes Again reducing diameter reduces power vice versa sure balance props after such trim job fashion can select motor purchase varying props cell-count attain very wide range operating power performance levels summary motors characterized perform very well similarly will good job flying some larger plane fact within limits measurement accuracy prop suitability again clear its prop motor determines electrical power required battery exactly what Ive written several times before its reason no fear doing article As expected cobalts some what lighter efficient ferrites cost no differences big enough prevent consideration products What requirement very least cell count very smallest current drain Great several motor prop/battery combinations will job can choose motor fea tures like best photos illustrate some Consider differences cooling methods prop adaptors mounting requirements slight variations weight consider availability As far can see motors should work well long time right applica tion purpose find best motorI dont think such exists Its like trying find best car best tennis racket best HandLaunched Glider short unless dictated some very special application require ment its individual matter preference choice Basic Electricity Part Two Last months column presented some simple electrical terms voltage current showed some analogies water pressure flow Youll recall voltage likened depth water over head tank current circuit unlike water flow through aquaresistance represented pipe diameter Also column said electrical power motors product multiplication voltage current Specifically power watts equal volts times amps higher power work can done given time Lots elec trical power can fly given plane up higher rate climb less electrical power Further clear voltage requires cells battery current demand drains given battery quickly larger plane requires larger motor capable han dling higher voltage/currents needed produce higher power Lets back up little start out simply Suppose consider flashlight has battery lamp lamp really small resistance wire connected battery results current flow lamp load battery voltage times current flows power delivered lamp power produces heatthe small resistance wire ele ment gets extremely hot glows brightly similar though bigger example - For Foam Its Best Deal Best PEANUT SCALE MODEU Kits $895 ZEROMILES M-I8 PIETENPOLDRUINE PIPER cusCOUGAR ANDRESONGIPSY MOTH MUSTANGLACEY M-lOGANAGOBIE SPORT MODEU BABY ACE$849 ONE NITE 28$695 ONE NITE IS$695 STRINGLESS$495 PECK ROG$198 RADIO 3LIIdPS CONTROLLED II sad 13 FOOT LONGKITS OR READY TO FLY NOW IN THREE COLORS GRAY ORANGE YELLOW LOW PRICES CATALOG No 25 $150 PHONE 819 442-4636 619 489-8675 LA MESA CA 92041 Model Aviation LLL iii eacn ve Marina Del Rey UA ~i 1-624 FOAM WING CORES TOM FOAM CUTTING iiwd PRAIRIE BIRD T $598 Custom Cut i- iau 1u ruse IS OCEAN STATE AEROMODEL ENGINEERING$14995 21 Jeyc Dr ~ Dealer & Kit Weat Warwick RI 02893Manufacturers WS4 4018288813Inquiries Invited Coming Soon e F8F BearCat Modelers Choice GMP EPOXIES High Quality Model Construction Jr Kwik Set 6 Minute5 oz $595 Kwik Set 6 Minute10 Os $995 Giant Kwik Set 6 Minute16 os$1395 Half FastlOMinutelOoz$895 GMP AIRCRAFT INSTRUMENTS 80in31161/4318112$ 149 40 3/4 inch $149 EASY OFF PULLER proper tool removing drive washersand flywheels $ 795 Gas Model Products 8773 Russet Dr Cincinnati OH 45239 513 385-7398 out e8 dealer order Ante Poat add $150 electric clothes iron Power levels 1000 watts typical household irons takes lot power heat keep such implement hot light typical flashlight former much bigger job done power needed examples electrical power input resistive loads produces heat and/or light relationships elec trical terms involved given Ohms Law can expressed very simple arithmetic expression written three different ways 1 Voltage ent x resistance 2 Current age/Resistance 3 Resistance age/Current case two terms known third unknown may found easily example lets say flashlight battery consisted two cells having cell chemistry produces 15 volts cell terminals cells properly installed typical flashlight con nected series total voltage sum two three volts Now lets say flashlight lamp has resistance 12 ohms typical value informa tion current flowing lamp can found formula 2 /12 current amps V voltage R resistance ohms Suppose now werent able see light lamp knew some current being taken battery some kind load might know because connected multimeters pictured last month such fashion battery current output read same lamp above current meter would read amp might recon nect multimeter read voltage scale use read battery voltage would say 3 volts could easily determine circuit load resistance formula 3 R 3/1/4 e divided one-fourth hms Cash Check Stamps 32 Page Tabloid size illustrated DISCOUNT Catalog Sent 1st Class Mail COMET COX FLYLINE FOX GOLDBERG GUILLOWS JETCO K&fl PACTRA PECK POLYMER PERFECT SIG- STERLiNG SULLIVAN TOP FLITE & OTHERS PENN VALLEY HOBBY CENTER 917 1 Main 3t Lana1sPa 19146 21Sf 865 t268 3680010 SPARROWHAWK 1/32 SCALE PLASTIC MODEL KIT AJS US Navy Sparrowhawks operated two dirigibles aircraft carrier during 1930s among colorful aircraft aviations Golden Age KIT FEATURES U Decals permit finishing model six different Sparrowhawks Two types wheels hard flexible tires U Monofilament rigging U Detailed interior Send $1 complete catalog kits accessories Dept MA WILLIAMS BROTHERS INC 181 PAWNEE ST SAN MARCOS CA 92069 Just exactly use multimeter simple measurements will covered future column now gonna move learn about electrical parameterpower stated above power product voltage current Thus formula relationship Power age x Current P power P expressed watts Look above formulas use little imagination can see power can related circuit load resistance example formula 1 know V Suppose use equality stuff left side equals sign exactly same stuff right side equals sign can used stead other place V formula power Accepted arithmetic practice allows done have P I P IxIxR identical P red PR x needed Similarly should clear P V x V/R Now weve written formulas lets show can put use calculating power used light bulb flashlight Although going three different ways results going same time First lets use volts amps P 3 x att Next well use current resistance P x 12 x 12 = Y4 watt Finally well use voltage resistance P 2 3/ watt April 1985 151 FIBERGLASS & FOAM V CONSTRUCTION FAI & AMA PATtERN 60-61 ENGINE #84 SPAN 704 sq AREA WEIGHT 8 LBS DEPENDING ON EQUIP BASIC KIT$10795 DELUXE KITS15995 Call 10U AM IC 9101 PM Mail-Sal 1115A & MASIER CARD L S L MODEL DEALER & 01ST6000 BCPRODUCTS INQUIRIES INVITEDf513 341-0012 7342 6dg COiliI DnIonlI 0140 46247 AMERICAN JUNIOR .404 Interceptor new A-P404 foldIng wing interreptor lao refresher count Have Fun II youve never Ilown youll fhrillaofhewingsunloldiotosoarlogsi5htllyoUhavC flown heloreif will come back Now can oson ol GREATAMERICAN JUNIOR CLOSSICSYonII love It.and ao will everyone else 404 BuIlder lOt$395 404 AIU595 404 RTF795 74 Glider195 Boa 548 743-in-l Pak495Oregon City 0R97045 See year Oubby Oealer c stock rely order 11001 order direct Poet auc aud 0odliOu Chaeuee 1300 foe first model plus 1091 oddrtluOal RCFS II RADIO CONTROLLED FLIGHT SIMULATOR John Kallend FOR APPLE 11 lie GREAT AS TRAINING AID FOR BEGINNER OR -PPm PIAJY AEROBATIC INCLUDING SPINS AND SNAP ROUS CONFIGURE FOR LARGE VARIETY OF MODELS FROM TRAINERS TO HOT AERORATIC MODELS USE WITH DAVE BROWN PRODUCTS DUAL JOY STICK TRANSMrITEW FOR THE MOST ACCURATE SIMULATION OF R/C PLYING CAN BE USED WITH ANY APPLE COMPATABLE JOYSTICK IT EVEN HAS DUAL RATE CONTROL SENSmVITY NOSE BEGUIREI APPLE II PUll 48K sInI E II WITH BIlE DRIVE AND AR APPLE COMPATARLE JOY 551CR OR DAVE BROWN PRODUCIS DUAl JOYSTICIC TEANIMmEB DAVE BROWN PRODUCTS Notice earlier discussion using hundreds watts turn large propellers fast takes less watt light flashlight So whats have motors batteries Electrics hangs together friends Stay tuned youll have lot insight Electrics work tune out maybe thisll help win some future contestsif meantime please direct ques tions SASE author Happy Electric landings Bob Kopski 25 West End Dr Lansdale PA 19446 RC Old-Timers/Mathews Continued page 55 Its glue Recently laying some laminated outlines down flashed through mind way Hank Struck others should have Available Now Commodore lLZ4\-\~4 V 4860 LAYHIGH HAMILTON OHIO 45013 done designs dawned us bent wire tubing original ly used Apache Cabruler forth werent done laminated balsa simply because nitrocellulose Ambroid Comet etc glue available adhesive such simple thing spray three four layers /16 / whatever dilute ammonia water coat layers aliphatic resin glue Sig Bond etc pull around form pins Hank likely now uses technique himself try Ambroid some time Weve seen TV commercials ask Wheres beef time another modelers must have asked Wheres CG weve built kit manufacturer has done work us shows us plans center gravity CG supposed fact better approximately shows us its supposed model going fly well crunch comes weve got latest masterpiece completed ready flight seldom happens CG has come out money want new plane live weve got add some ballast plane make CG move its sup posed Sure can use age-old cut-and-try method may too time-consuming difficult some cases What neat solution problem published recent edition news letter Lehigh Valley PA RC Club Tom Bilheimer editor order use method described youll need accurate scalepreferably graduated ounces Youll also need accurate ruler yardstick might better scheme described makes use princi ple balancing moments plans show location CG Lets say supposed 375 behind leading edge LE wing Since may convenient meas ure different fixed spot model lets use tip spinner end crankshaft Lets seethe CG should 1075 point Hmmm After finding marking balance point new model find CG actually 10375 reference point means plane nose-heavy weve got add some weight tail Wed like add little weight possible well put near tail possible Measuring plane find can add some weight inconspicuously point 31 inches reference point much weight find out answer question well have use little arithmetic multi plication division some algebra will multiply distance reference point nose location actual CG weight model add product distance reference point place can add ballast times unknown added weight divide sum models weight unknown added weight Well set 152 Model Aviation Complete DIN Line ofFx~ - Quality Finishing Products DIN Pto FESSIONALS CHOICE Kin Craft Mig 14323 TwIn Ridge Court Ashland Kentucky 41101 606 928-4763 ASK FOR US AT TOUR FAVORITE HOllY SHOP GONTIOLINI TillS PROFILECOMBA 7RA T WIDE & NARROW WEDGE 75 -- 6 Capacities INIFLOW & STIIDD Guiton Dliii Fuels Ingredients Fof detailed brochuaCOc stamps/check oisi CAROLINA-TAFFINDER 8345 Delhi Road charleston Hgts. SC 29418 803-563-7169 DeHAVILLAND BEAVER GIANT SCALE 96 4CYCLE9O120 SEND $200 FOR COMPLETE CATALOG OF FINE KITS IKON NWST ox 566 Auburn WA 98071 206941-8248