Radio Technique

George Myers ANOTHER KIND battery charger Life full changes happen around us adapt question today react realize hold piece future hands didnt realize doing Mr Gerry Jarvis MEN Model Engineering Norwalk 54 Chestnut Hill Norwalk CT 06851 extolling virtues new pulse-charger 1980 WRAMS show Gerry could see interested enough lay money 7 Transition Low High Rate Complete Rapid Charging Trace Path -__ 4 00 r 900 down Let send you can convince yourself about week UPS man left package contents appear photo above viewed mixed delight hand need things write about want stay abreast industry other accepting package committed hours research testing things recom mend things understand have used have found safe efficient additions hobby have tested used MEN Trajectory High Charging Rate Voltage Magnitude High Rate Peak Above Battery Voltage ia Pm portional Battery Resistance Trajectory Low Charging Rate Voltage x Battery Voftage Monitored Chargerl observed output voltage characteristics MEN charger direct-coupled oscilloscope resulting oscillogram looks like sketch High Rate LW flickering Low Charging Rate trajectory used stall times batteryvoltage above preset cut off voltage 55 VDC 4-cell pack High Charging Rate trajectory used battery voltage below point transition moves Oto go degrees battery voltage risestrom 40 55 VDC High Rate charging ceases battery voltage above 55 VDC charger 2 months rewrite column third time keep learning new things about device good does work Briefly MEN C-S 0/4 pulse-charger Instead pushing usual small steady current batteries pops short pulses much larger current During periods no charging current flowing battery C-50/4 measures battery voltage battery voltage below 125 volts per cell charging takes place high rate light-emitting diode LED lights signal fact As battery voltage rises above 125 volts per cell charging rate tapers down lower level LED flickers Finally battery voltage above 1 40 volts per cell charging current cuts back trickle-charge level can left connected months LED extinguishes Dont try use control points other charger Testing MEN C-50/4 began accep tance testing process reading chargers instruction manual must read carefully because contains lot information very few words done transferred atten tion publication GET-3148A NICKELCADMIUM BATTERY APPLICATION HANDBOOK General Electric Co Battery Business Dept PO Box 861 Gainsville FL 32602 $5 refresh memory batteries cannot measure charging current DCorACmeters will damaged trying Thus saith MEN manual got out trusty Heathkit 10-45 30 oscillo scope clipped charger wires copper er ed waveform seemed half-wave rectified 60 Hz AC clipped about 25 VDC Next connected junked 4-cell flight pack charger observed waveforms diagram waveforms included elsewhere column picture showed battery voltage funnylooking peaks riding Obviously theres control somewhere circuit modulat ing charging current varying firing angle triac After LED flickered went out Switching scope AC increasing gain showed pulses still very reduced amplitude trickle mode absolutely must read charging current buy yourself moving-magnet type DC ammeter type meter simple rugged cheap widely respected its ability integrate weird waveforms like charger used EMICO NF2C-2 102 made Electro Mech Instrument Co Perkasie PA about 25 years ago part metered glow battery setup made up CL models meter has range 0-5 amps DC reads about 3/4 amp high-rate charging correlates well battery discharge measurements showing full charge put back about trickle charge too small read meter equivalent about 20 ma pulled pack oil charger shortly after switchover trickle charging took place discharged 300 maH bad Gerry Repeat test Flickering stopped 23 minutes Dis 16 Model Aviation N MEN C-50/4 charger received isa Model 14 8 cells evidenced absence alpha character before serial number case charge 300 maH Put pack back charger went bed Next day after returning home work discharged pack again charger 16 hours Discharge capacity ws 475 maH Perhaps theres some mistake Repeat test Flickering stopped 34 minutes after 16 hours capacity measured 475 maH No mistake point 111 quote C-50/4 manual RC system cycling good reasons cycling RC system never before charged MEN Charger Three five deep discharge charge cycles should performed soon possible cycle 24 hours after receiving charger cycling will improve capacity batteries addition cycling improves reliability batteries Further cycling does help hinder batteries good Another portion states During factory tests charger have never battery kept charger develop short have able clear some shorts cells packs obtain usable capacity batteries However batteries charged other chargers shorted cells reappeared after several charge cycles Weve demonstrated increase capacity about short-circuit repairs took out very old very dead set cells somehow avoided trip garbage can charger grunted over hour half instruction manual advised Watching oscillo scope could see cells come up one start exercise two cells shorted two flat 0 VDC shorted After 90 minutes MEN charger 3 4 cells showed better 1 volt very warm touch previous pack never got warm Maximum current drawn charger 110 VAC Now interesting thing about cells over 4 years old removed transmitter after 750 charge/discharge cycles shown 275 maH capacity rated 600 removed have dormant 9 months punched up 135 volts per cell 90 minutes C-50/4 charger discharged 10 ohm resistor average 320 ma rate measured capacity 400 maH Resistance 3 cells about 1/10th ohm charged 4/10 ohm discharged characteristics typical used cells still have some working life left Section 6 GE handbook deals discharge characteristics wont quote message Cell resistance AA battery 028 ohms new Cell resistance lowest fully charged rises significantly end discharge Cell resistance increases significantly temperature drops less rapidly rises Cell resistance increases age Cell capacity diminishes slowly age use til 50% loss noted Capacity diminishes rapidly Therefore cell con sidered expended fails exhibit 50% rated capacity after thorough recondi tioning 200C took another transmitter off shelf tested its pack rather typical history always recharged manufacturers 50 ma charger seen partial discharges service Capacity measured Unicycle 5000 down 350 maH candidate battery replacement Discharging Unicycle 5000 2-hour rate end-point 10 volts per cell followed 16-hour recharging C-50/4 yielded 350 375 400 400 maH After last test attached 10 ohm 10 watt resistorRadio Shack P/N 271-132 pack took way down 0 VDC An 8-hour recharge new charger yielded capacity 450 maH Thats 29% improvement takes pack out consideration replacement Well fly another year keep watching its performance results hand settled down some serious testing Im going bore details Suffice say Tim used C-50/4 pump up set nickle cadmium batteries could lay hands showed least 10% improvement capacity showed up 30% improvement used pump up nickle-cadmium D cell use glow plug battery case Continued page 107 September 1980 17 landing dont Cut throttle too soon model slows quickly other hand idle low enough ship can float right past landing difficult get down Begin pull tail down flare just before touchdown since airfoil section stab really works Otherwise Fleet flies just like trainer Relax enjoy making big lazy maneu vers just like full-size Fleet Specifications Scale 2 an 56 lgth 42 wing area 860 sq wght 5 lbs engine 35 40 Four-channel radio rudder elevator motor ailerons RC Technique/Myers continued page 17 knew shift low rate would never take place used time clock shut off charger after 5 hours 4 amphr hrs worked just fine dont know what long-term results will expect good queried Gerry about long-term effects told could offer fact 6-year-old World Engines transmitter has attached prototype charger 18 months occasional time out flying battery testing batteries original Gould AA still test 113 minutes Flite-Life now think Pulse Charging pay attention C-50/4 available five models coding little obscure Model Serial No preceded blank space charging 4 8 cell systems common combination Model II Serial No preceded H charging 4 5 cell systems Kraft Sport seriesmodification required Model III Serial No preceded X charging 4 10 cell systems Old Kraft Signature World Engines Model IV Serial No preceded 5 charging 4 9 cell systems Cox/Sanwa modification required Model V Serial No preceded R charging two 4-cell flight packs reason concern about numbers cells charger shifts High Low rate strictly basis voltage Thats instructed check back 90 minutes after begin charging High rate LED still either have shorted output used wrong charger have shorted cell pack C-50/4 cant fix What happens forget check back High-rate LED stays First continue charging High rate batteries get hot old ones did Next pressure builds up cells vents open Eventually cells dry out charging current ceases flow According Mr Jarvis has charged 20 packs destruction way explcded got hot enough damage heat useable either Users C-50/4 will have learn check instruction manual contains warning case will get uncomfortably warm Mine doesnt Bob Aberles does suspect difference tightly transformer plates connected serious complaint fact unit has ungrounded metal case Since modelers work cellars naked concrete floors think unit should have 3-wire plug cord plugged properly grounded 110 VAC receptacles re placed line cord Calectro No L3-7 18 Continued page 112 Only $1995 M-60 AD Motor Mou Fit WEBRA 91 0 SUEVIA 15 Cu & Otherb~j.Ya Quadra Motor Mount Only $1995 Free Floating 22Mount SEE YOUR Only $1 6954 COJUSTABLE Dect St ppee,te7 5 Pipe IVI U11EAses heSedded CC edditienei hoid sees Ouadra Motor ,oaie agee ADi MUFFLER OUR 1980/81 CATALOG IS OFF THE PRESS Ace R/Cs completely revised 1980/81 Catalog off press features over 80 pages containing thousands fl/C products over 100 manufacturers including ourselves specialize hardto-get items Please send $2 copy ACE R/C INC BOX SuE HIGGINSVILLE MO 64037 816 584-7121 SIMITAR WINS 1St PLACEPATTERN PRENOVICE 1979 WINTER NATS SI MI TAR SI MI TAR SI MI TAR SI MI TAR SI MI TAR SI MI TAR SIMIlAR SI MI TAR NEW. SIMITAR SPORT 9- 40 Power 50 Inch Span Standard Kit Includes Ply Wing Sheeting Foam Cores Balsa Fuselage Gear Formed Sliding Tray Full Sitc Plans $5995 SIMIlAR WINS 1St PLACENORTHROP FLYING WING CONTEST 1979 NEWT-SHIRTS High Quality 100 t utton $ ____ 95 Multi-color Silkscreen Si/es 5 M L & XL Fleck Rider YellowPlus $100 Astron Light BlueShipping Simitar 540 TanCharge SEE YOUR DEALER OR ORDER ROM BILL EVANS AIR/~CRAFT 20825 ROSCOE BLVD CANOGA PARK CA 91306 TEL 2l3 344-639 OR 709-0894 September 1980 107 Name __________________ Address II CItyStZip ISEND FOR FREE CATALOGI WHEELS CONTROL-UNEFREE-FUGHT SCALE PILOTS CYUNDERS ENGINE KITS MACHINE GUN KITS PLASTIC DISPLAY MODELS SEND $1 FOR COMPLETE ILLUSTRATED CATALOG DEPT MA PAWNEE ST SAN MARCOS CA 9 VINTAGESMOOTHGOLDEN AGENEW sizes21/3CONTOURsizes214BALLOON 3431/i"234 31/i 13341314 133h2hz4/ 11443/i114334 11/44%31451/4 11451144s/ 11/i53 156/a214514 1/a6A AiMs sliding clearance mentioned above time hold-down tabs attached excess length extending below deck level assembly should tried its fit fuselage careful windshield rear closure correct height slide blocks ride size 1/32 diameter music wire laminated after groove filed both matching cemented surfaces groove will followed #60 drill sharp end piece freshly cut 1/32 wire Make least ten thesewell oversize may trimmed have wire hole parallel perpendicular edges After assembly checked fitting fuselage deck wise establish guide wire positions attach slider blocks working workboard fixture Once satisfaction can mask transparent sections paint frames Canopy frames painted using aluminum pig mented dope masked cellophane scotch tape Mounting fuselage becomes simple task can done last item final assembly RC Aerobatics/Van Putte continued page 25 purchased local electronics store $230 figure Im worth ground lug went under transformer mounting screw show elsewhere column Gerrys convinced Future lots charger will have charger short-circuit reverse-polarity protected batteries arent Five minutes hooked up backwards wont destroy bat teries 5 hours will right save Observations experiences MEN C-50/4 charger I The charger usually goes High rate charging few minutes no matter much have used batteries doesnt happen immediately Sometimes takes 30 seconds switch take place 2 If need reassurance charger really working two ways initiate High rate charging recommended way c batteries charger plug charger 110 VAC supply alterna tive Ivc using ill effects momentarily connect charger pack polarity reversed High rate usually comes plug charger correctly after treatment 3 This great last charger As examplc last Saturday spent morning yard helicopter came lunch plugged system C-50/4 lunch over ready continue flying half-hour charger puts back about charge 4 The trickle charger great too leave helicopter connected time its always fully charged ready go 5 If charger seems noisy tighten screws bend side-plates little Its quiet everything tight 6 Heres Gerry Jarvis Always dis connect charger before turning RC system might unlucky enough have switch makes up system before releases charger case high voltage charger might damage system 7 How about dont need ESV tell its right go flying High rate LED out youre ready Well George what really think charger obsoletes charger own complaint wasnt set up charge 9-cell Cox/Sanwa transmitters Gerry sold us adjusted satisfy needs stamped 5 its chest added catalog Model IV time next year expect see dozen imitations market theyll have hustle beat price $3695 list closing Id like acknowledge postcard John Deneke Glen Rock NJ sent May 1979 John reports has fixing RC systems 12 years has storing batteries C/l00 trickle charger longer Hes found no ill effects process C-50/4 works different principle may find Johns testimony dispells some doubts about continuous storage trickle charge Thanks John Keep postmen busy thanks reading column George M Myers 70 Froehlich Farm Roaa Hicks rule NY 11801 Canopies Kragness continued page 23 internal sliding element Locate make slots center canopy tabs make matching slots fuselage deck course good idea coat transparent areas masking material both inside out Fingers bench top tools will carry ccment thinncr scratches smears will occur unless some protection first applied Now determine proper windshield height drawing set place place forward unit between guides measure its height Trim away lower edges until reaches height doing take care remains symmetrical parallel deck Now cut other two pieces nested inside other relative heights allow about 0 10 clearance top between center element sliding section necessary establish front sliding element windshield height first others pro gressively reduced height result density example almost 25% elevator deflection required same size loop airplane 7000 feet sea level effect aileron control compli cated Lower air density causes reduction torque generated deflection ailerons also causes reduction reverse torque generated rolling airplane Since two torques oppose other maximum roll rate airplane can achieve full aileron throw effect air density maximum roll rate generally found increase roll rate altitude other words fliers find airplanes need less aileron throw altitude sea level third effect altitude can real problem pattern fliers Power output engines ability propellers convert rotary motion thrust dramatically affected air density overall effect operation altitude available thrust varies approximately square density Compared sea level thrust available 7000 feet about 66% can expected sea level Since vertical performance strongly affected thrust available loss st can disastrous Sport fliers will find flying altitude may require moving up engine size compensate loss available thrust Pattern fliers generally able since competition rules limit engine size 61 cubic inches possibility should considered pattern flying altitude build 40-size airplane power 60size engine Flying airplanes higher altitudes can done requires lot care persistence us sea level fliers can think about having fly 5000 10000 feet get depressed problems great things about RC oriented newsletters AMA forwards reading humor contain An excel lent example published SIRS Sentral Illinois Radio Society newsleter co-editors Bill Bev Sellberg feature sort Dear Abby column character called Rudder Brudder issue contained following Dear Rudder Brudder out flying beautiful day last fall bit problem 112 Model Aviation SCALE RADIO CONTROL