CONGRATULATIONS order Bernard Cawley Auburn WA placing second Sport Scale Sportsman class 89 Nats Electric first Nats history Ber nard used /6-scale 1946 Taylorcraft modeled af ter operates Kent WA Bernards T Craft has geared 40 cobalt 18 l200-mAh Ni Cds Jomar SC-4 speed controller spins 12 x 7 prop Bernard member Puget Sound Electric Model Fliersthe same club also claims Mitch Poling Model Builders Electric columnist Nicely done Bernard Speed controls subject last Oc tober 89 column time left some things hanging Specifically discussion re garding high-rate frame-rate designs indicated preference former promised reasons future col umn future now First review speed controls know vary speed motor varying aver age voltage applied motor terminals done pulse-width-modulating motor bat tery voltage simply means given period time called cycle speed con trol switches battery motor opens path repeats action over over period plus Off period form cy cle time time Off times equal motor would average over time receive half battery voltage Clearly motor voltage hence motor speed increases higher ra tios On-to-Off times decreases Off time becomes longer time given cycle Varying transmitters throttle stick position varies transmitted control signal pulse width speed control acts upon vary motor voltage On/Off times Frame-rate controls have time equal transmitter frame rateusually about 50 Hz same rate servos receive updated information High-rate controls also vary On/Off times battery applied motor much greater frequency shorter cycle times frame-rate frequency controls still use same throttle-channel pulse-width infor mation use control symmetry On/Off time ratio internal oscillator clock running much faster Usually clocks run several thousand hertzaudio fre quencies October column also mentioned mo tors running frame-rate controls may emit sound like rattle rumble especially low speed Also motors high-rate controls may emit whine singing sound sounds simply effect two widely dif fering speeds motor voltage switched off review out way can move along short relevant story Earlier year did lot Skyvolt flying experimental purposes two planes play having great time designs accept wide range power systems better over-tOOwatt motors upwards past 200-watt motiva tors As result spent quite bit time swap ping variety motors batteries speed con trols two planes process mentioned above noticed occasion cobalt 15 running quite hotin fact very hot new motor immediately suspected defect perhaps shorted turn winding armature what ever pulled motor checked bench found just fine substituted another anyway flew it too ran very hot battery also hotter normal end flight Normal what used years fly ing specifically what other Skyvolt displaying Obviously something wrong first Skyvolt right what could speed control troubled plane frame-rate design speed control other happened SC-4a high-rate design Swapping speed controls also swapped high heat experience Skyvolt another 56 Model Aviation Radio Control Electrics Bob Kopski 25 West End Dr Lansdale PA 19446 Doug Bills reports Airtronics Eclipse excellent Deluxe kit comes complete motor Mabuchi Leisure gear drive folding prop Wings tip panels unplug transport Strain-relief units greatly reduce stresses wire-to-circuit-board solder joints Small point ers indicate short pieces Du-Bro heat-shrink tubing CyAd either circuit board top IC Three-lead receiver wires go through tubes before being soldered Dont heatshrink tubing though An RJM OnlOff controller left Jomar SC-4 right High Skys tidy little OnlOff controller Three screws lower left setscrews ter minal block slip ends heavy motorlbattery wires holes tighten screws No soldering needed very nature simply dig bench set up experiment cobalt 15 8 x 4 prop first running adjustable lab sup ply establish reference conditions particu lar wanted measure armature shaft tempera ture rear bearing after specified motor run time 10000 rpm exact speed espe cially important case represents about 110 watts about half power wide-open 15 After three minutes running two min utes rest time temperature 548 0C Ambient temperature 249 0C Next cooled motor ambient blower repeated testbut time set supply voltage represent average 12-cell pack under such load about 135 volts stalled frame-rate speed control path sent signal 10000 rpm attained al lowed motor run another three minutes measured same temperature point stopped motor after two minutes found 942 0C friends big-time heat Remember water boils lOOT Finally after again fully cooling motor Ire peated same experiment SC-4 found resulting motor temperature 620 0C think conclusion obvious have related story years KRC Electric Fly about three weeks writing September 16-17 will Continued page 162 TEXAS SLOW4 Championship Outstanding 4 Strong & Stable New Combat/Sport4 FastEasyAssembly Plane4 High Performance Includes Complete HardwareEngine Included 0 Bellcrank outs s 0 Hinges s & Nuts 0 Precision Foam Wing Cares $100 catalog control-line combat specialties Dealer & Distributor inquiries Welcome 760 Waltonville Road Hummelstown PA 17036 566-3810 December 1989 57 Bob talks about installing RF chokes speed control leads months column Sequence goes bottom-to-top Ace RIC #LL1O6 lO-microhenry choke flex lead wire soldered shortened choke leads 1-in length red Du-Bro heat-shrink tubing tub ing shrunk over choke soldered joints three choke units bundled yellow h/s tub ing connectors added Unit shown experimental insert cable trying choke idea existing installations installing chokes leave about 1-2 flex wire speed control unit choke neres two neat schemes orienting pairs Sermos connectors dont con nect two sets wires wrong polar ity Sermos connectors dont come male/female pairs design such connector serves either function Inte gral tabs/grooves connector body al low ease stacking connectors Latest Lightweight Contoured Acrylic Handle gel celled battery POWER HANDLE COILED CORD Great ror Runway Restans Torque Larger Engines Durable Aylir Non-sap Grip 6 Foot coiled Cord Nirad Holster STABILIZOR4000 POWER HANDLE & CORD2000 COILED CORD ONLY1000 HANDLE CORD & GEL CELL BATrERY POSTAGE & HANDLING350 Washingtea Reeldr,te Add 81% KDI 10426 SE 206th P1 Kent WA 98031 854-8053 Seligs amazing airfoils starting 53021 root transitioning 53014 tips Falcon 880 Perkins raced beefed up ballasted appropriately weighed over eight pounds news Mark Allen found interesting since hed designed plane 675-lb maximum weight mind wing glassed sported arrow-shaft hinges other wise Allens original thermaling design Its truly beautiful Glider did look out place sitting ground beside straight-winged Slope Racers air another story Mark Grand modified Super Co manche garnered five wins second place Mark put home court advantage work found both lift speed outdistance Perkins RCM Magazine Soaring columnist Don Edberg placed third point behind Grand flyoff decided fourth fifth places Estancia regulars Tony Martin Jason Perrin tied nine points Tonys one-off fiberglass de sign Jasons Snipe collided flyoff Snipe going down Martins ship taking fourth overall Jerry Bridgeman unanimously voted win ner Pilots Choice trophy losing planes Jerry went through new Slope/Electric design two standard Snipes earn coveted award Special thanks go Contest Director Ray Kuntz organizing event Chuck Al len Chucks Model Shop Hawthorne trophies years Mats included F3F-style Slope Race no ones surprise Daryll Perkins ran away everyone captured first place both classes Ive opportunity watch Daryll fly couple races year its hard see successful Daryll smoothest fliers around Theres noth ing showy spectacular about way flies just very very consistent As dramatic proof take look variety planes Daryll has flown victory recent monthshis Comet Davenport Mats Falcon Hughes Hill Ron Vanns Eliminator Mats 16-oz/sq-ft limit Coming next time will look connec tion between Slope flying F3B Ill discuss ing similarities exist between two dis ciplines planes pilots RC Electrics/Kopski Continued page 57 flight highest total time four-minute segments plus fraction last partial seg ment wins thinking about event would ap proach participant set about study flight duration cruise power levels various planes idea see much en ergy storage could pack plane al locate speed control needed just maintain altitude effect applying own Rule Thumb #1 MA April 1984 page 77 says power cruise ex pressed watts input motor numerically equals weight plane pounds multi plied wing loading oz per sq foot course rule thumb approximation study involved running carefully con trolled experiments three planes First Challenger modified include geared co balt 15 10 l2-Ah SCEs speed control also ran experiments Eurekaa threechannel sport plane direct-drive Astro 25 14 1 2-Ah SCs speed control Finally ran additional experiments Nytique night-flying Amptique derivative has six 12Ah SCRs economy RC car motor pod speed control three widely varying model designs speed control installa tion such frame-rate high-rate con trols could easily swapped field flew tiring cruise-type flights collect data flight flown carefully mea sured charge ampere-minutes empty wherein charge deliberately made below batteries label capacity flights flown throttle control carefully set allow nonclimbing cruise levels power just enough throttle maintain low-altitude ovals around field Flight tests covered nearly two months under variety temperature humidity wind conditions After amassing respectable data array fol lowing conclusions clearly stood out e Rule Thumb #1 definitely does ballpark ex pected flight results just what approximation should dobut high-rate controls actual flight times vary dramatically de pending type speed control used par ticular cruise times much shorter using frame-rate controls Also case mo tor battery much hotter end flight clear heat associated framerate controls result power wasted power available turn prop fly plane long could done using high-rate controls particulars follows Challenger described above predicted cruise time about 25 minutes average time framerate control 185 minutes highrate control 304 minutes Remember no-thermal flying Eureka cruised average 66 95 minutes respectively Rule Thumb #1 prediction 98 minutes limited data short charges Nytique cruised 24 minutes 39 minutes respectively Predicted time 49 minutes As difference results between speed control types thats explainable Ill get next month now clear under conditions described model power sys tems efficient high-rate controls arc used Actually its control thats efficient rather its motor gains efficiency used high-rate controls high motor battery temperature shorter far flight times clearly show honest expected difference didnt expect such large difference Anyway some thoughts Speed controls often advertised evalu ated exclusive regard on-resistance voltage loss full Frankly con trols know use several MOSFETS metal oxide semiconductor field-effect transistors Ed parallel unless some kind basic blunder within given design should have less same small voltage dropthe same good MOSFETS available manufacturers loss really meaning full-on lossdoes story tell apparent above Besides full-on way control used servo-driven switch electronic switch would better choice May suggest youif youre planning speed control purchase intend vary speed motor modeldo strongly con sider results above course would often just cruise around described above Generally speaking youre going use speed control other full-on youre better off high-rate design would expect since nothing ever simple frame-rate types generally smaller lighter lower cost Decisions decisions Im personally familiar speed con trols high-rate ones know include Jomar SC-4 discontinued too bad SC-5 SM equivalents So also Elden Ken EKE 24U Im told RAM Red 06 have 24U use optically coupled Ill soon using Red 06 optically coupled now have obtained data J0162 Model Aviation Almost Ready Fly. Requires few hours asmbf. Includes necessary accessories/hardware. Balsa construction precovered 20-25 Size CHEROKEE 48 wing span Special 0 Size now available $11296 S&H $600 BLBW PO Box 3634 Cerritos CA 90703-3634Th@ itea~@wDealer 213 940-127020 Size 95InquiriecCOD MofleyOrdws 40 Size 95AcceptedChecks Accepted tallow 7 addItional dayst introduce new event Maxi-Flight event designed technologist strategist pilot requires continuous flight task charge pilot required land relaunch after fourth minute mar units Given results above would seem reason able question ask high must high rate Surely rates between low-speed frame-rate types SC-4 highrate unit produce in-between results Also probably some high-rate value above little performance difference obtained sounds like winter project mefor come future first speed control matter great interest matter non-optically-coupled speed con trols glitching see October 89 MA page 59 get see test fly large number Electrics process experience wide variety flight performance results too often experience case motorinduced glitching recently saw case truly phenomenal level same effect plane unflyable fact ground range motor running measurable tens feet Substituting different radio significantly im proved situation concluded something wrong first radio advised pilot send warranty re pair brand new first asked could try something Since speed control case optically coupled wanted try separate speed control receiver radio frequencies installed three small chokes three speed-control-toreceiver leads effectively broke radio/speed control connection radio frequency DC servo-pulse-signal condi tions worked just great plane perfectly flyable what still believe defective radio Since success two other systems per formed normally meaning somewhat glitchy flyable similarly modified good results normal glitching reduced significantly sounds like some thing would useful 10microhenry chokes available Ace R/C Inc part #LL106 SOC photo herein shows installing cannot assure same success ra dio speed control power system can find out yourself few bucks lit tle time now speed control item up coming new big-motor unit soon announced S ES MILLS MET5LS 500KS PRECISI0s INST5YIE5TS C0NLETE 5T5LOG $200 Ku IbIs 1t,S 4MPIIU GLf c 2100 C S1,s Rooc Spr,gfo1d 1ioo 45505 Compac3 13 322-8562 Jomar intended use 24 32 cells dont have release date price writing Interest can call write Jomar see ad magazine get prompt reliable accu rate answer goes service too could name some places hobby doesnt happenbut wont dont ask either Electric supplies available littleknown source SR Batteries Its SR lit tIe known indeed very well knownbut batteries fact SR can supply wide range Electric goodies including Astro Jomar Robbe KSC other name brands discount prices addition popular SR batteries latter bring quite bit reader mail espe cially high-capacity Magnums seems readers have really taken liking l250sa cell specified 1250 mAb capac ity physical size nominal weight familiar 800 ARs Ive some interesting correspondence Larry Sribnick chief charge arry tells wont tell anyone else just what cell-secrets Larry maintains proprietary info regarding suppliers processes cant blame him Its se cret success Anyway case youre aware Larry will make up custom battery packs re quirements Check SR ad issue send note get SR catalog tells except secrets As closing note remember Electrics work just great winter its very easy keep em clean low temperatures cause theres no thick sticky goo wipe off plane Happy quiet Electric landings everyone RC Scale/Parsons Continued page 59 batteries much easier quicker ac curate old-style analog voltmeter Beckman Circuitmate DM15B compact high quality has good ranges fac tors make ideal both workshop field box paid around 60 bucks about five years ago RC Helicopters/Jolly Continued page 60 special new feature Rebel hi-tech composite rotor head After much designing ex perimenting flight testing GMP has devel oped unique rotor head offers utmost simplicity performance new rotor head consists one-piece ny lon center unit dual-ball-bearing-supported hub Hiller flybar control pivots nylon center unit Prebent blade holders automatically adjust main rotor blade pitch optimum setting Hence Rebel very easy set up has fewest parts count rotor head market provides lots inherent static stability maintaining very adequate acro batic capability main rotor blades specifically designed matched maximize flight performance Rebel combination unique airfoil blade chord dimensions has produced flight re sponse very conducive learning tly quickly little no damage model Cyclic control soft yet responsive Altitude control normally less effective other fixed-pitch Helicopters much improved Rebel climbs descends ease precision improved altitude control re sult extensive research testing led simple yet very effective rotor blade head design standard starting system Rebel cone start now demanded discriminating mod elers worldwide greatly eases starting process eliminates problems can arise starting belt-type system Rebel however OMP has developed sys tem further accommodate airplane fliers special adapter electric starter no longer needed Rebel designed use standard airplane starter cone fit ted electric starters However rub ber insert may need reversed smaller opening engages Rebels starting cone clutch classic GMP standard one-piece design machined steel plastic pro vides superior reliable performance GMP clutch unit times expensive manufacture other plastic some twopiece metal clutches available today gives smoother engagement drive performance lasts virtually forever clutch bell fitted special lining individually factoryfitted particular OMP kit provide cor rect engagement reliable operating perform ance will buy Rebel aimed toward Continued page 167 December 1989 163 BLUES CA getting down get protected CA mask Safety Plus mask will eliminate CA fumes epoxy polyester resin vapors air breath Lightweight easy breathing comfortable CA Mask $1595 Paint Mask $2045 See hobby dealer first doesnt have what need order direct Safety Plus PO Box 1173 Dept 12M Clinton Mississippi 39056 Call toll free 1-800-842-7233 Mississippi dial 601-924-9640 VISA MASTERCARD accepted COD add $250 shipping handling included Dealer Inquiries Invited PLU5 Bob FiorenzeI Hobby Center Inc Dealer Yellow Aircraft Complete Line Mail Order Hobby Suppliex Now available Faatcover Covering Material Welt Shownoom 35 mm Dextey woridl Omegaleool Power Fuela Diacountad Z 420 W.t SR 434--407 3274353 Winter Spdnga FL 32708 'Fax 407 327-7148 FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH V HULL lESION IN USE SIIWE 1972 SEND SASE FOR CATALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066
Edition: Model Aviation - 1989/12
Page Numbers: 56, 57, 162, 163
CONGRATULATIONS order Bernard Cawley Auburn WA placing second Sport Scale Sportsman class 89 Nats Electric first Nats history Ber nard used /6-scale 1946 Taylorcraft modeled af ter operates Kent WA Bernards T Craft has geared 40 cobalt 18 l200-mAh Ni Cds Jomar SC-4 speed controller spins 12 x 7 prop Bernard member Puget Sound Electric Model Fliersthe same club also claims Mitch Poling Model Builders Electric columnist Nicely done Bernard Speed controls subject last Oc tober 89 column time left some things hanging Specifically discussion re garding high-rate frame-rate designs indicated preference former promised reasons future col umn future now First review speed controls know vary speed motor varying aver age voltage applied motor terminals done pulse-width-modulating motor bat tery voltage simply means given period time called cycle speed con trol switches battery motor opens path repeats action over over period plus Off period form cy cle time time Off times equal motor would average over time receive half battery voltage Clearly motor voltage hence motor speed increases higher ra tios On-to-Off times decreases Off time becomes longer time given cycle Varying transmitters throttle stick position varies transmitted control signal pulse width speed control acts upon vary motor voltage On/Off times Frame-rate controls have time equal transmitter frame rateusually about 50 Hz same rate servos receive updated information High-rate controls also vary On/Off times battery applied motor much greater frequency shorter cycle times frame-rate frequency controls still use same throttle-channel pulse-width infor mation use control symmetry On/Off time ratio internal oscillator clock running much faster Usually clocks run several thousand hertzaudio fre quencies October column also mentioned mo tors running frame-rate controls may emit sound like rattle rumble especially low speed Also motors high-rate controls may emit whine singing sound sounds simply effect two widely dif fering speeds motor voltage switched off review out way can move along short relevant story Earlier year did lot Skyvolt flying experimental purposes two planes play having great time designs accept wide range power systems better over-tOOwatt motors upwards past 200-watt motiva tors As result spent quite bit time swap ping variety motors batteries speed con trols two planes process mentioned above noticed occasion cobalt 15 running quite hotin fact very hot new motor immediately suspected defect perhaps shorted turn winding armature what ever pulled motor checked bench found just fine substituted another anyway flew it too ran very hot battery also hotter normal end flight Normal what used years fly ing specifically what other Skyvolt displaying Obviously something wrong first Skyvolt right what could speed control troubled plane frame-rate design speed control other happened SC-4a high-rate design Swapping speed controls also swapped high heat experience Skyvolt another 56 Model Aviation Radio Control Electrics Bob Kopski 25 West End Dr Lansdale PA 19446 Doug Bills reports Airtronics Eclipse excellent Deluxe kit comes complete motor Mabuchi Leisure gear drive folding prop Wings tip panels unplug transport Strain-relief units greatly reduce stresses wire-to-circuit-board solder joints Small point ers indicate short pieces Du-Bro heat-shrink tubing CyAd either circuit board top IC Three-lead receiver wires go through tubes before being soldered Dont heatshrink tubing though An RJM OnlOff controller left Jomar SC-4 right High Skys tidy little OnlOff controller Three screws lower left setscrews ter minal block slip ends heavy motorlbattery wires holes tighten screws No soldering needed very nature simply dig bench set up experiment cobalt 15 8 x 4 prop first running adjustable lab sup ply establish reference conditions particu lar wanted measure armature shaft tempera ture rear bearing after specified motor run time 10000 rpm exact speed espe cially important case represents about 110 watts about half power wide-open 15 After three minutes running two min utes rest time temperature 548 0C Ambient temperature 249 0C Next cooled motor ambient blower repeated testbut time set supply voltage represent average 12-cell pack under such load about 135 volts stalled frame-rate speed control path sent signal 10000 rpm attained al lowed motor run another three minutes measured same temperature point stopped motor after two minutes found 942 0C friends big-time heat Remember water boils lOOT Finally after again fully cooling motor Ire peated same experiment SC-4 found resulting motor temperature 620 0C think conclusion obvious have related story years KRC Electric Fly about three weeks writing September 16-17 will Continued page 162 TEXAS SLOW4 Championship Outstanding 4 Strong & Stable New Combat/Sport4 FastEasyAssembly Plane4 High Performance Includes Complete HardwareEngine Included 0 Bellcrank outs s 0 Hinges s & Nuts 0 Precision Foam Wing Cares $100 catalog control-line combat specialties Dealer & Distributor inquiries Welcome 760 Waltonville Road Hummelstown PA 17036 566-3810 December 1989 57 Bob talks about installing RF chokes speed control leads months column Sequence goes bottom-to-top Ace RIC #LL1O6 lO-microhenry choke flex lead wire soldered shortened choke leads 1-in length red Du-Bro heat-shrink tubing tub ing shrunk over choke soldered joints three choke units bundled yellow h/s tub ing connectors added Unit shown experimental insert cable trying choke idea existing installations installing chokes leave about 1-2 flex wire speed control unit choke neres two neat schemes orienting pairs Sermos connectors dont con nect two sets wires wrong polar ity Sermos connectors dont come male/female pairs design such connector serves either function Inte gral tabs/grooves connector body al low ease stacking connectors Latest Lightweight Contoured Acrylic Handle gel celled battery POWER HANDLE COILED CORD Great ror Runway Restans Torque Larger Engines Durable Aylir Non-sap Grip 6 Foot coiled Cord Nirad Holster STABILIZOR4000 POWER HANDLE & CORD2000 COILED CORD ONLY1000 HANDLE CORD & GEL CELL BATrERY POSTAGE & HANDLING350 Washingtea Reeldr,te Add 81% KDI 10426 SE 206th P1 Kent WA 98031 854-8053 Seligs amazing airfoils starting 53021 root transitioning 53014 tips Falcon 880 Perkins raced beefed up ballasted appropriately weighed over eight pounds news Mark Allen found interesting since hed designed plane 675-lb maximum weight mind wing glassed sported arrow-shaft hinges other wise Allens original thermaling design Its truly beautiful Glider did look out place sitting ground beside straight-winged Slope Racers air another story Mark Grand modified Super Co manche garnered five wins second place Mark put home court advantage work found both lift speed outdistance Perkins RCM Magazine Soaring columnist Don Edberg placed third point behind Grand flyoff decided fourth fifth places Estancia regulars Tony Martin Jason Perrin tied nine points Tonys one-off fiberglass de sign Jasons Snipe collided flyoff Snipe going down Martins ship taking fourth overall Jerry Bridgeman unanimously voted win ner Pilots Choice trophy losing planes Jerry went through new Slope/Electric design two standard Snipes earn coveted award Special thanks go Contest Director Ray Kuntz organizing event Chuck Al len Chucks Model Shop Hawthorne trophies years Mats included F3F-style Slope Race no ones surprise Daryll Perkins ran away everyone captured first place both classes Ive opportunity watch Daryll fly couple races year its hard see successful Daryll smoothest fliers around Theres noth ing showy spectacular about way flies just very very consistent As dramatic proof take look variety planes Daryll has flown victory recent monthshis Comet Davenport Mats Falcon Hughes Hill Ron Vanns Eliminator Mats 16-oz/sq-ft limit Coming next time will look connec tion between Slope flying F3B Ill discuss ing similarities exist between two dis ciplines planes pilots RC Electrics/Kopski Continued page 57 flight highest total time four-minute segments plus fraction last partial seg ment wins thinking about event would ap proach participant set about study flight duration cruise power levels various planes idea see much en ergy storage could pack plane al locate speed control needed just maintain altitude effect applying own Rule Thumb #1 MA April 1984 page 77 says power cruise ex pressed watts input motor numerically equals weight plane pounds multi plied wing loading oz per sq foot course rule thumb approximation study involved running carefully con trolled experiments three planes First Challenger modified include geared co balt 15 10 l2-Ah SCEs speed control also ran experiments Eurekaa threechannel sport plane direct-drive Astro 25 14 1 2-Ah SCs speed control Finally ran additional experiments Nytique night-flying Amptique derivative has six 12Ah SCRs economy RC car motor pod speed control three widely varying model designs speed control installa tion such frame-rate high-rate con trols could easily swapped field flew tiring cruise-type flights collect data flight flown carefully mea sured charge ampere-minutes empty wherein charge deliberately made below batteries label capacity flights flown throttle control carefully set allow nonclimbing cruise levels power just enough throttle maintain low-altitude ovals around field Flight tests covered nearly two months under variety temperature humidity wind conditions After amassing respectable data array fol lowing conclusions clearly stood out e Rule Thumb #1 definitely does ballpark ex pected flight results just what approximation should dobut high-rate controls actual flight times vary dramatically de pending type speed control used par ticular cruise times much shorter using frame-rate controls Also case mo tor battery much hotter end flight clear heat associated framerate controls result power wasted power available turn prop fly plane long could done using high-rate controls particulars follows Challenger described above predicted cruise time about 25 minutes average time framerate control 185 minutes highrate control 304 minutes Remember no-thermal flying Eureka cruised average 66 95 minutes respectively Rule Thumb #1 prediction 98 minutes limited data short charges Nytique cruised 24 minutes 39 minutes respectively Predicted time 49 minutes As difference results between speed control types thats explainable Ill get next month now clear under conditions described model power sys tems efficient high-rate controls arc used Actually its control thats efficient rather its motor gains efficiency used high-rate controls high motor battery temperature shorter far flight times clearly show honest expected difference didnt expect such large difference Anyway some thoughts Speed controls often advertised evalu ated exclusive regard on-resistance voltage loss full Frankly con trols know use several MOSFETS metal oxide semiconductor field-effect transistors Ed parallel unless some kind basic blunder within given design should have less same small voltage dropthe same good MOSFETS available manufacturers loss really meaning full-on lossdoes story tell apparent above Besides full-on way control used servo-driven switch electronic switch would better choice May suggest youif youre planning speed control purchase intend vary speed motor modeldo strongly con sider results above course would often just cruise around described above Generally speaking youre going use speed control other full-on youre better off high-rate design would expect since nothing ever simple frame-rate types generally smaller lighter lower cost Decisions decisions Im personally familiar speed con trols high-rate ones know include Jomar SC-4 discontinued too bad SC-5 SM equivalents So also Elden Ken EKE 24U Im told RAM Red 06 have 24U use optically coupled Ill soon using Red 06 optically coupled now have obtained data J0162 Model Aviation Almost Ready Fly. Requires few hours asmbf. Includes necessary accessories/hardware. Balsa construction precovered 20-25 Size CHEROKEE 48 wing span Special 0 Size now available $11296 S&H $600 BLBW PO Box 3634 Cerritos CA 90703-3634Th@ itea~@wDealer 213 940-127020 Size 95InquiriecCOD MofleyOrdws 40 Size 95AcceptedChecks Accepted tallow 7 addItional dayst introduce new event Maxi-Flight event designed technologist strategist pilot requires continuous flight task charge pilot required land relaunch after fourth minute mar units Given results above would seem reason able question ask high must high rate Surely rates between low-speed frame-rate types SC-4 highrate unit produce in-between results Also probably some high-rate value above little performance difference obtained sounds like winter project mefor come future first speed control matter great interest matter non-optically-coupled speed con trols glitching see October 89 MA page 59 get see test fly large number Electrics process experience wide variety flight performance results too often experience case motorinduced glitching recently saw case truly phenomenal level same effect plane unflyable fact ground range motor running measurable tens feet Substituting different radio significantly im proved situation concluded something wrong first radio advised pilot send warranty re pair brand new first asked could try something Since speed control case optically coupled wanted try separate speed control receiver radio frequencies installed three small chokes three speed-control-toreceiver leads effectively broke radio/speed control connection radio frequency DC servo-pulse-signal condi tions worked just great plane perfectly flyable what still believe defective radio Since success two other systems per formed normally meaning somewhat glitchy flyable similarly modified good results normal glitching reduced significantly sounds like some thing would useful 10microhenry chokes available Ace R/C Inc part #LL106 SOC photo herein shows installing cannot assure same success ra dio speed control power system can find out yourself few bucks lit tle time now speed control item up coming new big-motor unit soon announced S ES MILLS MET5LS 500KS PRECISI0s INST5YIE5TS C0NLETE 5T5LOG $200 Ku IbIs 1t,S 4MPIIU GLf c 2100 C S1,s Rooc Spr,gfo1d 1ioo 45505 Compac3 13 322-8562 Jomar intended use 24 32 cells dont have release date price writing Interest can call write Jomar see ad magazine get prompt reliable accu rate answer goes service too could name some places hobby doesnt happenbut wont dont ask either Electric supplies available littleknown source SR Batteries Its SR lit tIe known indeed very well knownbut batteries fact SR can supply wide range Electric goodies including Astro Jomar Robbe KSC other name brands discount prices addition popular SR batteries latter bring quite bit reader mail espe cially high-capacity Magnums seems readers have really taken liking l250sa cell specified 1250 mAb capac ity physical size nominal weight familiar 800 ARs Ive some interesting correspondence Larry Sribnick chief charge arry tells wont tell anyone else just what cell-secrets Larry maintains proprietary info regarding suppliers processes cant blame him Its se cret success Anyway case youre aware Larry will make up custom battery packs re quirements Check SR ad issue send note get SR catalog tells except secrets As closing note remember Electrics work just great winter its very easy keep em clean low temperatures cause theres no thick sticky goo wipe off plane Happy quiet Electric landings everyone RC Scale/Parsons Continued page 59 batteries much easier quicker ac curate old-style analog voltmeter Beckman Circuitmate DM15B compact high quality has good ranges fac tors make ideal both workshop field box paid around 60 bucks about five years ago RC Helicopters/Jolly Continued page 60 special new feature Rebel hi-tech composite rotor head After much designing ex perimenting flight testing GMP has devel oped unique rotor head offers utmost simplicity performance new rotor head consists one-piece ny lon center unit dual-ball-bearing-supported hub Hiller flybar control pivots nylon center unit Prebent blade holders automatically adjust main rotor blade pitch optimum setting Hence Rebel very easy set up has fewest parts count rotor head market provides lots inherent static stability maintaining very adequate acro batic capability main rotor blades specifically designed matched maximize flight performance Rebel combination unique airfoil blade chord dimensions has produced flight re sponse very conducive learning tly quickly little no damage model Cyclic control soft yet responsive Altitude control normally less effective other fixed-pitch Helicopters much improved Rebel climbs descends ease precision improved altitude control re sult extensive research testing led simple yet very effective rotor blade head design standard starting system Rebel cone start now demanded discriminating mod elers worldwide greatly eases starting process eliminates problems can arise starting belt-type system Rebel however OMP has developed sys tem further accommodate airplane fliers special adapter electric starter no longer needed Rebel designed use standard airplane starter cone fit ted electric starters However rub ber insert may need reversed smaller opening engages Rebels starting cone clutch classic GMP standard one-piece design machined steel plastic pro vides superior reliable performance GMP clutch unit times expensive manufacture other plastic some twopiece metal clutches available today gives smoother engagement drive performance lasts virtually forever clutch bell fitted special lining individually factoryfitted particular OMP kit provide cor rect engagement reliable operating perform ance will buy Rebel aimed toward Continued page 167 December 1989 163 BLUES CA getting down get protected CA mask Safety Plus mask will eliminate CA fumes epoxy polyester resin vapors air breath Lightweight easy breathing comfortable CA Mask $1595 Paint Mask $2045 See hobby dealer first doesnt have what need order direct Safety Plus PO Box 1173 Dept 12M Clinton Mississippi 39056 Call toll free 1-800-842-7233 Mississippi dial 601-924-9640 VISA MASTERCARD accepted COD add $250 shipping handling included Dealer Inquiries Invited PLU5 Bob FiorenzeI Hobby Center Inc Dealer Yellow Aircraft Complete Line Mail Order Hobby Suppliex Now available Faatcover Covering Material Welt Shownoom 35 mm Dextey woridl Omegaleool Power Fuela Diacountad Z 420 W.t SR 434--407 3274353 Winter Spdnga FL 32708 'Fax 407 327-7148 FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH V HULL lESION IN USE SIIWE 1972 SEND SASE FOR CATALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066
Edition: Model Aviation - 1989/12
Page Numbers: 56, 57, 162, 163
CONGRATULATIONS order Bernard Cawley Auburn WA placing second Sport Scale Sportsman class 89 Nats Electric first Nats history Ber nard used /6-scale 1946 Taylorcraft modeled af ter operates Kent WA Bernards T Craft has geared 40 cobalt 18 l200-mAh Ni Cds Jomar SC-4 speed controller spins 12 x 7 prop Bernard member Puget Sound Electric Model Fliersthe same club also claims Mitch Poling Model Builders Electric columnist Nicely done Bernard Speed controls subject last Oc tober 89 column time left some things hanging Specifically discussion re garding high-rate frame-rate designs indicated preference former promised reasons future col umn future now First review speed controls know vary speed motor varying aver age voltage applied motor terminals done pulse-width-modulating motor bat tery voltage simply means given period time called cycle speed con trol switches battery motor opens path repeats action over over period plus Off period form cy cle time time Off times equal motor would average over time receive half battery voltage Clearly motor voltage hence motor speed increases higher ra tios On-to-Off times decreases Off time becomes longer time given cycle Varying transmitters throttle stick position varies transmitted control signal pulse width speed control acts upon vary motor voltage On/Off times Frame-rate controls have time equal transmitter frame rateusually about 50 Hz same rate servos receive updated information High-rate controls also vary On/Off times battery applied motor much greater frequency shorter cycle times frame-rate frequency controls still use same throttle-channel pulse-width infor mation use control symmetry On/Off time ratio internal oscillator clock running much faster Usually clocks run several thousand hertzaudio fre quencies October column also mentioned mo tors running frame-rate controls may emit sound like rattle rumble especially low speed Also motors high-rate controls may emit whine singing sound sounds simply effect two widely dif fering speeds motor voltage switched off review out way can move along short relevant story Earlier year did lot Skyvolt flying experimental purposes two planes play having great time designs accept wide range power systems better over-tOOwatt motors upwards past 200-watt motiva tors As result spent quite bit time swap ping variety motors batteries speed con trols two planes process mentioned above noticed occasion cobalt 15 running quite hotin fact very hot new motor immediately suspected defect perhaps shorted turn winding armature what ever pulled motor checked bench found just fine substituted another anyway flew it too ran very hot battery also hotter normal end flight Normal what used years fly ing specifically what other Skyvolt displaying Obviously something wrong first Skyvolt right what could speed control troubled plane frame-rate design speed control other happened SC-4a high-rate design Swapping speed controls also swapped high heat experience Skyvolt another 56 Model Aviation Radio Control Electrics Bob Kopski 25 West End Dr Lansdale PA 19446 Doug Bills reports Airtronics Eclipse excellent Deluxe kit comes complete motor Mabuchi Leisure gear drive folding prop Wings tip panels unplug transport Strain-relief units greatly reduce stresses wire-to-circuit-board solder joints Small point ers indicate short pieces Du-Bro heat-shrink tubing CyAd either circuit board top IC Three-lead receiver wires go through tubes before being soldered Dont heatshrink tubing though An RJM OnlOff controller left Jomar SC-4 right High Skys tidy little OnlOff controller Three screws lower left setscrews ter minal block slip ends heavy motorlbattery wires holes tighten screws No soldering needed very nature simply dig bench set up experiment cobalt 15 8 x 4 prop first running adjustable lab sup ply establish reference conditions particu lar wanted measure armature shaft tempera ture rear bearing after specified motor run time 10000 rpm exact speed espe cially important case represents about 110 watts about half power wide-open 15 After three minutes running two min utes rest time temperature 548 0C Ambient temperature 249 0C Next cooled motor ambient blower repeated testbut time set supply voltage represent average 12-cell pack under such load about 135 volts stalled frame-rate speed control path sent signal 10000 rpm attained al lowed motor run another three minutes measured same temperature point stopped motor after two minutes found 942 0C friends big-time heat Remember water boils lOOT Finally after again fully cooling motor Ire peated same experiment SC-4 found resulting motor temperature 620 0C think conclusion obvious have related story years KRC Electric Fly about three weeks writing September 16-17 will Continued page 162 TEXAS SLOW4 Championship Outstanding 4 Strong & Stable New Combat/Sport4 FastEasyAssembly Plane4 High Performance Includes Complete HardwareEngine Included 0 Bellcrank outs s 0 Hinges s & Nuts 0 Precision Foam Wing Cares $100 catalog control-line combat specialties Dealer & Distributor inquiries Welcome 760 Waltonville Road Hummelstown PA 17036 566-3810 December 1989 57 Bob talks about installing RF chokes speed control leads months column Sequence goes bottom-to-top Ace RIC #LL1O6 lO-microhenry choke flex lead wire soldered shortened choke leads 1-in length red Du-Bro heat-shrink tubing tub ing shrunk over choke soldered joints three choke units bundled yellow h/s tub ing connectors added Unit shown experimental insert cable trying choke idea existing installations installing chokes leave about 1-2 flex wire speed control unit choke neres two neat schemes orienting pairs Sermos connectors dont con nect two sets wires wrong polar ity Sermos connectors dont come male/female pairs design such connector serves either function Inte gral tabs/grooves connector body al low ease stacking connectors Latest Lightweight Contoured Acrylic Handle gel celled battery POWER HANDLE COILED CORD Great ror Runway Restans Torque Larger Engines Durable Aylir Non-sap Grip 6 Foot coiled Cord Nirad Holster STABILIZOR4000 POWER HANDLE & CORD2000 COILED CORD ONLY1000 HANDLE CORD & GEL CELL BATrERY POSTAGE & HANDLING350 Washingtea Reeldr,te Add 81% KDI 10426 SE 206th P1 Kent WA 98031 854-8053 Seligs amazing airfoils starting 53021 root transitioning 53014 tips Falcon 880 Perkins raced beefed up ballasted appropriately weighed over eight pounds news Mark Allen found interesting since hed designed plane 675-lb maximum weight mind wing glassed sported arrow-shaft hinges other wise Allens original thermaling design Its truly beautiful Glider did look out place sitting ground beside straight-winged Slope Racers air another story Mark Grand modified Super Co manche garnered five wins second place Mark put home court advantage work found both lift speed outdistance Perkins RCM Magazine Soaring columnist Don Edberg placed third point behind Grand flyoff decided fourth fifth places Estancia regulars Tony Martin Jason Perrin tied nine points Tonys one-off fiberglass de sign Jasons Snipe collided flyoff Snipe going down Martins ship taking fourth overall Jerry Bridgeman unanimously voted win ner Pilots Choice trophy losing planes Jerry went through new Slope/Electric design two standard Snipes earn coveted award Special thanks go Contest Director Ray Kuntz organizing event Chuck Al len Chucks Model Shop Hawthorne trophies years Mats included F3F-style Slope Race no ones surprise Daryll Perkins ran away everyone captured first place both classes Ive opportunity watch Daryll fly couple races year its hard see successful Daryll smoothest fliers around Theres noth ing showy spectacular about way flies just very very consistent As dramatic proof take look variety planes Daryll has flown victory recent monthshis Comet Davenport Mats Falcon Hughes Hill Ron Vanns Eliminator Mats 16-oz/sq-ft limit Coming next time will look connec tion between Slope flying F3B Ill discuss ing similarities exist between two dis ciplines planes pilots RC Electrics/Kopski Continued page 57 flight highest total time four-minute segments plus fraction last partial seg ment wins thinking about event would ap proach participant set about study flight duration cruise power levels various planes idea see much en ergy storage could pack plane al locate speed control needed just maintain altitude effect applying own Rule Thumb #1 MA April 1984 page 77 says power cruise ex pressed watts input motor numerically equals weight plane pounds multi plied wing loading oz per sq foot course rule thumb approximation study involved running carefully con trolled experiments three planes First Challenger modified include geared co balt 15 10 l2-Ah SCEs speed control also ran experiments Eurekaa threechannel sport plane direct-drive Astro 25 14 1 2-Ah SCs speed control Finally ran additional experiments Nytique night-flying Amptique derivative has six 12Ah SCRs economy RC car motor pod speed control three widely varying model designs speed control installa tion such frame-rate high-rate con trols could easily swapped field flew tiring cruise-type flights collect data flight flown carefully mea sured charge ampere-minutes empty wherein charge deliberately made below batteries label capacity flights flown throttle control carefully set allow nonclimbing cruise levels power just enough throttle maintain low-altitude ovals around field Flight tests covered nearly two months under variety temperature humidity wind conditions After amassing respectable data array fol lowing conclusions clearly stood out e Rule Thumb #1 definitely does ballpark ex pected flight results just what approximation should dobut high-rate controls actual flight times vary dramatically de pending type speed control used par ticular cruise times much shorter using frame-rate controls Also case mo tor battery much hotter end flight clear heat associated framerate controls result power wasted power available turn prop fly plane long could done using high-rate controls particulars follows Challenger described above predicted cruise time about 25 minutes average time framerate control 185 minutes highrate control 304 minutes Remember no-thermal flying Eureka cruised average 66 95 minutes respectively Rule Thumb #1 prediction 98 minutes limited data short charges Nytique cruised 24 minutes 39 minutes respectively Predicted time 49 minutes As difference results between speed control types thats explainable Ill get next month now clear under conditions described model power sys tems efficient high-rate controls arc used Actually its control thats efficient rather its motor gains efficiency used high-rate controls high motor battery temperature shorter far flight times clearly show honest expected difference didnt expect such large difference Anyway some thoughts Speed controls often advertised evalu ated exclusive regard on-resistance voltage loss full Frankly con trols know use several MOSFETS metal oxide semiconductor field-effect transistors Ed parallel unless some kind basic blunder within given design should have less same small voltage dropthe same good MOSFETS available manufacturers loss really meaning full-on lossdoes story tell apparent above Besides full-on way control used servo-driven switch electronic switch would better choice May suggest youif youre planning speed control purchase intend vary speed motor modeldo strongly con sider results above course would often just cruise around described above Generally speaking youre going use speed control other full-on youre better off high-rate design would expect since nothing ever simple frame-rate types generally smaller lighter lower cost Decisions decisions Im personally familiar speed con trols high-rate ones know include Jomar SC-4 discontinued too bad SC-5 SM equivalents So also Elden Ken EKE 24U Im told RAM Red 06 have 24U use optically coupled Ill soon using Red 06 optically coupled now have obtained data J0162 Model Aviation Almost Ready Fly. Requires few hours asmbf. Includes necessary accessories/hardware. Balsa construction precovered 20-25 Size CHEROKEE 48 wing span Special 0 Size now available $11296 S&H $600 BLBW PO Box 3634 Cerritos CA 90703-3634Th@ itea~@wDealer 213 940-127020 Size 95InquiriecCOD MofleyOrdws 40 Size 95AcceptedChecks Accepted tallow 7 addItional dayst introduce new event Maxi-Flight event designed technologist strategist pilot requires continuous flight task charge pilot required land relaunch after fourth minute mar units Given results above would seem reason able question ask high must high rate Surely rates between low-speed frame-rate types SC-4 highrate unit produce in-between results Also probably some high-rate value above little performance difference obtained sounds like winter project mefor come future first speed control matter great interest matter non-optically-coupled speed con trols glitching see October 89 MA page 59 get see test fly large number Electrics process experience wide variety flight performance results too often experience case motorinduced glitching recently saw case truly phenomenal level same effect plane unflyable fact ground range motor running measurable tens feet Substituting different radio significantly im proved situation concluded something wrong first radio advised pilot send warranty re pair brand new first asked could try something Since speed control case optically coupled wanted try separate speed control receiver radio frequencies installed three small chokes three speed-control-toreceiver leads effectively broke radio/speed control connection radio frequency DC servo-pulse-signal condi tions worked just great plane perfectly flyable what still believe defective radio Since success two other systems per formed normally meaning somewhat glitchy flyable similarly modified good results normal glitching reduced significantly sounds like some thing would useful 10microhenry chokes available Ace R/C Inc part #LL106 SOC photo herein shows installing cannot assure same success ra dio speed control power system can find out yourself few bucks lit tle time now speed control item up coming new big-motor unit soon announced S ES MILLS MET5LS 500KS PRECISI0s INST5YIE5TS C0NLETE 5T5LOG $200 Ku IbIs 1t,S 4MPIIU GLf c 2100 C S1,s Rooc Spr,gfo1d 1ioo 45505 Compac3 13 322-8562 Jomar intended use 24 32 cells dont have release date price writing Interest can call write Jomar see ad magazine get prompt reliable accu rate answer goes service too could name some places hobby doesnt happenbut wont dont ask either Electric supplies available littleknown source SR Batteries Its SR lit tIe known indeed very well knownbut batteries fact SR can supply wide range Electric goodies including Astro Jomar Robbe KSC other name brands discount prices addition popular SR batteries latter bring quite bit reader mail espe cially high-capacity Magnums seems readers have really taken liking l250sa cell specified 1250 mAb capac ity physical size nominal weight familiar 800 ARs Ive some interesting correspondence Larry Sribnick chief charge arry tells wont tell anyone else just what cell-secrets Larry maintains proprietary info regarding suppliers processes cant blame him Its se cret success Anyway case youre aware Larry will make up custom battery packs re quirements Check SR ad issue send note get SR catalog tells except secrets As closing note remember Electrics work just great winter its very easy keep em clean low temperatures cause theres no thick sticky goo wipe off plane Happy quiet Electric landings everyone RC Scale/Parsons Continued page 59 batteries much easier quicker ac curate old-style analog voltmeter Beckman Circuitmate DM15B compact high quality has good ranges fac tors make ideal both workshop field box paid around 60 bucks about five years ago RC Helicopters/Jolly Continued page 60 special new feature Rebel hi-tech composite rotor head After much designing ex perimenting flight testing GMP has devel oped unique rotor head offers utmost simplicity performance new rotor head consists one-piece ny lon center unit dual-ball-bearing-supported hub Hiller flybar control pivots nylon center unit Prebent blade holders automatically adjust main rotor blade pitch optimum setting Hence Rebel very easy set up has fewest parts count rotor head market provides lots inherent static stability maintaining very adequate acro batic capability main rotor blades specifically designed matched maximize flight performance Rebel combination unique airfoil blade chord dimensions has produced flight re sponse very conducive learning tly quickly little no damage model Cyclic control soft yet responsive Altitude control normally less effective other fixed-pitch Helicopters much improved Rebel climbs descends ease precision improved altitude control re sult extensive research testing led simple yet very effective rotor blade head design standard starting system Rebel cone start now demanded discriminating mod elers worldwide greatly eases starting process eliminates problems can arise starting belt-type system Rebel however OMP has developed sys tem further accommodate airplane fliers special adapter electric starter no longer needed Rebel designed use standard airplane starter cone fit ted electric starters However rub ber insert may need reversed smaller opening engages Rebels starting cone clutch classic GMP standard one-piece design machined steel plastic pro vides superior reliable performance GMP clutch unit times expensive manufacture other plastic some twopiece metal clutches available today gives smoother engagement drive performance lasts virtually forever clutch bell fitted special lining individually factoryfitted particular OMP kit provide cor rect engagement reliable operating perform ance will buy Rebel aimed toward Continued page 167 December 1989 163 BLUES CA getting down get protected CA mask Safety Plus mask will eliminate CA fumes epoxy polyester resin vapors air breath Lightweight easy breathing comfortable CA Mask $1595 Paint Mask $2045 See hobby dealer first doesnt have what need order direct Safety Plus PO Box 1173 Dept 12M Clinton Mississippi 39056 Call toll free 1-800-842-7233 Mississippi dial 601-924-9640 VISA MASTERCARD accepted COD add $250 shipping handling included Dealer Inquiries Invited PLU5 Bob FiorenzeI Hobby Center Inc Dealer Yellow Aircraft Complete Line Mail Order Hobby Suppliex Now available Faatcover Covering Material Welt Shownoom 35 mm Dextey woridl Omegaleool Power Fuela Diacountad Z 420 W.t SR 434--407 3274353 Winter Spdnga FL 32708 'Fax 407 327-7148 FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH V HULL lESION IN USE SIIWE 1972 SEND SASE FOR CATALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066
Edition: Model Aviation - 1989/12
Page Numbers: 56, 57, 162, 163
CONGRATULATIONS order Bernard Cawley Auburn WA placing second Sport Scale Sportsman class 89 Nats Electric first Nats history Ber nard used /6-scale 1946 Taylorcraft modeled af ter operates Kent WA Bernards T Craft has geared 40 cobalt 18 l200-mAh Ni Cds Jomar SC-4 speed controller spins 12 x 7 prop Bernard member Puget Sound Electric Model Fliersthe same club also claims Mitch Poling Model Builders Electric columnist Nicely done Bernard Speed controls subject last Oc tober 89 column time left some things hanging Specifically discussion re garding high-rate frame-rate designs indicated preference former promised reasons future col umn future now First review speed controls know vary speed motor varying aver age voltage applied motor terminals done pulse-width-modulating motor bat tery voltage simply means given period time called cycle speed con trol switches battery motor opens path repeats action over over period plus Off period form cy cle time time Off times equal motor would average over time receive half battery voltage Clearly motor voltage hence motor speed increases higher ra tios On-to-Off times decreases Off time becomes longer time given cycle Varying transmitters throttle stick position varies transmitted control signal pulse width speed control acts upon vary motor voltage On/Off times Frame-rate controls have time equal transmitter frame rateusually about 50 Hz same rate servos receive updated information High-rate controls also vary On/Off times battery applied motor much greater frequency shorter cycle times frame-rate frequency controls still use same throttle-channel pulse-width infor mation use control symmetry On/Off time ratio internal oscillator clock running much faster Usually clocks run several thousand hertzaudio fre quencies October column also mentioned mo tors running frame-rate controls may emit sound like rattle rumble especially low speed Also motors high-rate controls may emit whine singing sound sounds simply effect two widely dif fering speeds motor voltage switched off review out way can move along short relevant story Earlier year did lot Skyvolt flying experimental purposes two planes play having great time designs accept wide range power systems better over-tOOwatt motors upwards past 200-watt motiva tors As result spent quite bit time swap ping variety motors batteries speed con trols two planes process mentioned above noticed occasion cobalt 15 running quite hotin fact very hot new motor immediately suspected defect perhaps shorted turn winding armature what ever pulled motor checked bench found just fine substituted another anyway flew it too ran very hot battery also hotter normal end flight Normal what used years fly ing specifically what other Skyvolt displaying Obviously something wrong first Skyvolt right what could speed control troubled plane frame-rate design speed control other happened SC-4a high-rate design Swapping speed controls also swapped high heat experience Skyvolt another 56 Model Aviation Radio Control Electrics Bob Kopski 25 West End Dr Lansdale PA 19446 Doug Bills reports Airtronics Eclipse excellent Deluxe kit comes complete motor Mabuchi Leisure gear drive folding prop Wings tip panels unplug transport Strain-relief units greatly reduce stresses wire-to-circuit-board solder joints Small point ers indicate short pieces Du-Bro heat-shrink tubing CyAd either circuit board top IC Three-lead receiver wires go through tubes before being soldered Dont heatshrink tubing though An RJM OnlOff controller left Jomar SC-4 right High Skys tidy little OnlOff controller Three screws lower left setscrews ter minal block slip ends heavy motorlbattery wires holes tighten screws No soldering needed very nature simply dig bench set up experiment cobalt 15 8 x 4 prop first running adjustable lab sup ply establish reference conditions particu lar wanted measure armature shaft tempera ture rear bearing after specified motor run time 10000 rpm exact speed espe cially important case represents about 110 watts about half power wide-open 15 After three minutes running two min utes rest time temperature 548 0C Ambient temperature 249 0C Next cooled motor ambient blower repeated testbut time set supply voltage represent average 12-cell pack under such load about 135 volts stalled frame-rate speed control path sent signal 10000 rpm attained al lowed motor run another three minutes measured same temperature point stopped motor after two minutes found 942 0C friends big-time heat Remember water boils lOOT Finally after again fully cooling motor Ire peated same experiment SC-4 found resulting motor temperature 620 0C think conclusion obvious have related story years KRC Electric Fly about three weeks writing September 16-17 will Continued page 162 TEXAS SLOW4 Championship Outstanding 4 Strong & Stable New Combat/Sport4 FastEasyAssembly Plane4 High Performance Includes Complete HardwareEngine Included 0 Bellcrank outs s 0 Hinges s & Nuts 0 Precision Foam Wing Cares $100 catalog control-line combat specialties Dealer & Distributor inquiries Welcome 760 Waltonville Road Hummelstown PA 17036 566-3810 December 1989 57 Bob talks about installing RF chokes speed control leads months column Sequence goes bottom-to-top Ace RIC #LL1O6 lO-microhenry choke flex lead wire soldered shortened choke leads 1-in length red Du-Bro heat-shrink tubing tub ing shrunk over choke soldered joints three choke units bundled yellow h/s tub ing connectors added Unit shown experimental insert cable trying choke idea existing installations installing chokes leave about 1-2 flex wire speed control unit choke neres two neat schemes orienting pairs Sermos connectors dont con nect two sets wires wrong polar ity Sermos connectors dont come male/female pairs design such connector serves either function Inte gral tabs/grooves connector body al low ease stacking connectors Latest Lightweight Contoured Acrylic Handle gel celled battery POWER HANDLE COILED CORD Great ror Runway Restans Torque Larger Engines Durable Aylir Non-sap Grip 6 Foot coiled Cord Nirad Holster STABILIZOR4000 POWER HANDLE & CORD2000 COILED CORD ONLY1000 HANDLE CORD & GEL CELL BATrERY POSTAGE & HANDLING350 Washingtea Reeldr,te Add 81% KDI 10426 SE 206th P1 Kent WA 98031 854-8053 Seligs amazing airfoils starting 53021 root transitioning 53014 tips Falcon 880 Perkins raced beefed up ballasted appropriately weighed over eight pounds news Mark Allen found interesting since hed designed plane 675-lb maximum weight mind wing glassed sported arrow-shaft hinges other wise Allens original thermaling design Its truly beautiful Glider did look out place sitting ground beside straight-winged Slope Racers air another story Mark Grand modified Super Co manche garnered five wins second place Mark put home court advantage work found both lift speed outdistance Perkins RCM Magazine Soaring columnist Don Edberg placed third point behind Grand flyoff decided fourth fifth places Estancia regulars Tony Martin Jason Perrin tied nine points Tonys one-off fiberglass de sign Jasons Snipe collided flyoff Snipe going down Martins ship taking fourth overall Jerry Bridgeman unanimously voted win ner Pilots Choice trophy losing planes Jerry went through new Slope/Electric design two standard Snipes earn coveted award Special thanks go Contest Director Ray Kuntz organizing event Chuck Al len Chucks Model Shop Hawthorne trophies years Mats included F3F-style Slope Race no ones surprise Daryll Perkins ran away everyone captured first place both classes Ive opportunity watch Daryll fly couple races year its hard see successful Daryll smoothest fliers around Theres noth ing showy spectacular about way flies just very very consistent As dramatic proof take look variety planes Daryll has flown victory recent monthshis Comet Davenport Mats Falcon Hughes Hill Ron Vanns Eliminator Mats 16-oz/sq-ft limit Coming next time will look connec tion between Slope flying F3B Ill discuss ing similarities exist between two dis ciplines planes pilots RC Electrics/Kopski Continued page 57 flight highest total time four-minute segments plus fraction last partial seg ment wins thinking about event would ap proach participant set about study flight duration cruise power levels various planes idea see much en ergy storage could pack plane al locate speed control needed just maintain altitude effect applying own Rule Thumb #1 MA April 1984 page 77 says power cruise ex pressed watts input motor numerically equals weight plane pounds multi plied wing loading oz per sq foot course rule thumb approximation study involved running carefully con trolled experiments three planes First Challenger modified include geared co balt 15 10 l2-Ah SCEs speed control also ran experiments Eurekaa threechannel sport plane direct-drive Astro 25 14 1 2-Ah SCs speed control Finally ran additional experiments Nytique night-flying Amptique derivative has six 12Ah SCRs economy RC car motor pod speed control three widely varying model designs speed control installa tion such frame-rate high-rate con trols could easily swapped field flew tiring cruise-type flights collect data flight flown carefully mea sured charge ampere-minutes empty wherein charge deliberately made below batteries label capacity flights flown throttle control carefully set allow nonclimbing cruise levels power just enough throttle maintain low-altitude ovals around field Flight tests covered nearly two months under variety temperature humidity wind conditions After amassing respectable data array fol lowing conclusions clearly stood out e Rule Thumb #1 definitely does ballpark ex pected flight results just what approximation should dobut high-rate controls actual flight times vary dramatically de pending type speed control used par ticular cruise times much shorter using frame-rate controls Also case mo tor battery much hotter end flight clear heat associated framerate controls result power wasted power available turn prop fly plane long could done using high-rate controls particulars follows Challenger described above predicted cruise time about 25 minutes average time framerate control 185 minutes highrate control 304 minutes Remember no-thermal flying Eureka cruised average 66 95 minutes respectively Rule Thumb #1 prediction 98 minutes limited data short charges Nytique cruised 24 minutes 39 minutes respectively Predicted time 49 minutes As difference results between speed control types thats explainable Ill get next month now clear under conditions described model power sys tems efficient high-rate controls arc used Actually its control thats efficient rather its motor gains efficiency used high-rate controls high motor battery temperature shorter far flight times clearly show honest expected difference didnt expect such large difference Anyway some thoughts Speed controls often advertised evalu ated exclusive regard on-resistance voltage loss full Frankly con trols know use several MOSFETS metal oxide semiconductor field-effect transistors Ed parallel unless some kind basic blunder within given design should have less same small voltage dropthe same good MOSFETS available manufacturers loss really meaning full-on lossdoes story tell apparent above Besides full-on way control used servo-driven switch electronic switch would better choice May suggest youif youre planning speed control purchase intend vary speed motor modeldo strongly con sider results above course would often just cruise around described above Generally speaking youre going use speed control other full-on youre better off high-rate design would expect since nothing ever simple frame-rate types generally smaller lighter lower cost Decisions decisions Im personally familiar speed con trols high-rate ones know include Jomar SC-4 discontinued too bad SC-5 SM equivalents So also Elden Ken EKE 24U Im told RAM Red 06 have 24U use optically coupled Ill soon using Red 06 optically coupled now have obtained data J0162 Model Aviation Almost Ready Fly. Requires few hours asmbf. Includes necessary accessories/hardware. Balsa construction precovered 20-25 Size CHEROKEE 48 wing span Special 0 Size now available $11296 S&H $600 BLBW PO Box 3634 Cerritos CA 90703-3634Th@ itea~@wDealer 213 940-127020 Size 95InquiriecCOD MofleyOrdws 40 Size 95AcceptedChecks Accepted tallow 7 addItional dayst introduce new event Maxi-Flight event designed technologist strategist pilot requires continuous flight task charge pilot required land relaunch after fourth minute mar units Given results above would seem reason able question ask high must high rate Surely rates between low-speed frame-rate types SC-4 highrate unit produce in-between results Also probably some high-rate value above little performance difference obtained sounds like winter project mefor come future first speed control matter great interest matter non-optically-coupled speed con trols glitching see October 89 MA page 59 get see test fly large number Electrics process experience wide variety flight performance results too often experience case motorinduced glitching recently saw case truly phenomenal level same effect plane unflyable fact ground range motor running measurable tens feet Substituting different radio significantly im proved situation concluded something wrong first radio advised pilot send warranty re pair brand new first asked could try something Since speed control case optically coupled wanted try separate speed control receiver radio frequencies installed three small chokes three speed-control-toreceiver leads effectively broke radio/speed control connection radio frequency DC servo-pulse-signal condi tions worked just great plane perfectly flyable what still believe defective radio Since success two other systems per formed normally meaning somewhat glitchy flyable similarly modified good results normal glitching reduced significantly sounds like some thing would useful 10microhenry chokes available Ace R/C Inc part #LL106 SOC photo herein shows installing cannot assure same success ra dio speed control power system can find out yourself few bucks lit tle time now speed control item up coming new big-motor unit soon announced S ES MILLS MET5LS 500KS PRECISI0s INST5YIE5TS C0NLETE 5T5LOG $200 Ku IbIs 1t,S 4MPIIU GLf c 2100 C S1,s Rooc Spr,gfo1d 1ioo 45505 Compac3 13 322-8562 Jomar intended use 24 32 cells dont have release date price writing Interest can call write Jomar see ad magazine get prompt reliable accu rate answer goes service too could name some places hobby doesnt happenbut wont dont ask either Electric supplies available littleknown source SR Batteries Its SR lit tIe known indeed very well knownbut batteries fact SR can supply wide range Electric goodies including Astro Jomar Robbe KSC other name brands discount prices addition popular SR batteries latter bring quite bit reader mail espe cially high-capacity Magnums seems readers have really taken liking l250sa cell specified 1250 mAb capac ity physical size nominal weight familiar 800 ARs Ive some interesting correspondence Larry Sribnick chief charge arry tells wont tell anyone else just what cell-secrets Larry maintains proprietary info regarding suppliers processes cant blame him Its se cret success Anyway case youre aware Larry will make up custom battery packs re quirements Check SR ad issue send note get SR catalog tells except secrets As closing note remember Electrics work just great winter its very easy keep em clean low temperatures cause theres no thick sticky goo wipe off plane Happy quiet Electric landings everyone RC Scale/Parsons Continued page 59 batteries much easier quicker ac curate old-style analog voltmeter Beckman Circuitmate DM15B compact high quality has good ranges fac tors make ideal both workshop field box paid around 60 bucks about five years ago RC Helicopters/Jolly Continued page 60 special new feature Rebel hi-tech composite rotor head After much designing ex perimenting flight testing GMP has devel oped unique rotor head offers utmost simplicity performance new rotor head consists one-piece ny lon center unit dual-ball-bearing-supported hub Hiller flybar control pivots nylon center unit Prebent blade holders automatically adjust main rotor blade pitch optimum setting Hence Rebel very easy set up has fewest parts count rotor head market provides lots inherent static stability maintaining very adequate acro batic capability main rotor blades specifically designed matched maximize flight performance Rebel combination unique airfoil blade chord dimensions has produced flight re sponse very conducive learning tly quickly little no damage model Cyclic control soft yet responsive Altitude control normally less effective other fixed-pitch Helicopters much improved Rebel climbs descends ease precision improved altitude control re sult extensive research testing led simple yet very effective rotor blade head design standard starting system Rebel cone start now demanded discriminating mod elers worldwide greatly eases starting process eliminates problems can arise starting belt-type system Rebel however OMP has developed sys tem further accommodate airplane fliers special adapter electric starter no longer needed Rebel designed use standard airplane starter cone fit ted electric starters However rub ber insert may need reversed smaller opening engages Rebels starting cone clutch classic GMP standard one-piece design machined steel plastic pro vides superior reliable performance GMP clutch unit times expensive manufacture other plastic some twopiece metal clutches available today gives smoother engagement drive performance lasts virtually forever clutch bell fitted special lining individually factoryfitted particular OMP kit provide cor rect engagement reliable operating perform ance will buy Rebel aimed toward Continued page 167 December 1989 163 BLUES CA getting down get protected CA mask Safety Plus mask will eliminate CA fumes epoxy polyester resin vapors air breath Lightweight easy breathing comfortable CA Mask $1595 Paint Mask $2045 See hobby dealer first doesnt have what need order direct Safety Plus PO Box 1173 Dept 12M Clinton Mississippi 39056 Call toll free 1-800-842-7233 Mississippi dial 601-924-9640 VISA MASTERCARD accepted COD add $250 shipping handling included Dealer Inquiries Invited PLU5 Bob FiorenzeI Hobby Center Inc Dealer Yellow Aircraft Complete Line Mail Order Hobby Suppliex Now available Faatcover Covering Material Welt Shownoom 35 mm Dextey woridl Omegaleool Power Fuela Diacountad Z 420 W.t SR 434--407 3274353 Winter Spdnga FL 32708 'Fax 407 327-7148 FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH V HULL lESION IN USE SIIWE 1972 SEND SASE FOR CATALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066