This Isan example kind model standsto benefitfrom system synchronize engine speed particular model Jerry Bugnis Piper Seneca ii photographed its takeoff roil 1978 AMA Nationals sync system keys weaker engine Have steered clear twin-engined planes because thought couldnt getthe revs two engines always match flight device may answer U Joseph G Utasi THERE ARE LOTS good reasons use sync system models 1 allows engines match rpm hassle matching engines linkages 2 Engines close unequai displacement can used together no performance penalty 3 keeps thrust equal under load conditions allow ing improved flight performance Now can finally build twin buying another engine engine sync system wont make bad engines run better wont keep engine shutting down will keep rpm both engines equal over normal operating range did choose design such system Perhaps its some deep desire carve niche myself record books modeldom could desire provide badly needed Essential development electronics project good test equip ment Pulse generator left sync system middle engine simulator right Tektronix 2213 scope background 32 Model Aviation say use enough powerthat boaro will tiy did serve its purpose dynamic teat bed device modeling fraternity Basically think main reason just because near thing time real engineering challenge Development system began winter 1979 snowbound hills Cincinnati Several prototypes built tested minimum success first engine rpm sensors problem Optical sensing tried proved unreliable variable lighting near prop hub Finally Hall-effect sensors used two small magnets mounted rear spinner backplate did trick second major problem cleanly sense master engine running some minimum speed required engage sync system After some embarrassingly compli cated circuitry simple effective circuit settled first approach sync detector phase-locked loopsort obvious solution engineering mentality After show its done full-scale twins approach came very close being workable slave engine would never settle out same rpm master would hunt like bad servo does turned out rpm could match BOTTOM VIEW OF PRINTED CIRCUIT BOARD ENGINE SYNC SYSTEM DRWN BY R OHARA COMPONENT PLACEMENT DIAGRAM sCALE 2 X 1 48 VOLTS SLAVE SENSOR GROUND 48 VOLTS MASTER SENSOR GROUND 4 0 0 0 R2R4cJRI4 RI OD~6O JG= CiD1 7 o R3 R5 A4A3@I1 jI UI c:: A21I RIO ~R8LJ ~RI3 R2I Q2 R7JR2 48 VOLTS MASTER INPUT GROUND 0 48 VOLTS SLAVE OUTPUT GROUND having same phase other words both engines would notfire exactly same instant Believe phase-locked loop would try correct changing throttle positon As can imagine resulted system could never satisfied back drawing board agalo last time around benefit over year thought testing suggestions close friend Don Langer new circuit design called differential integrator did trickit matched rpm ignored phase engine respect other also gave better overall sync responsesmall changes servo position small rpm differOctober 1982 33 PC board measures 1 /4 x 2 just about size Ace Bantam servo Finished board should enclosed small plastic case safety good fit some cyanoacrylate glue should used keep two magnets place spinner backplate EXPERIMENTAL TWIN ENGINE SYNC SYSTEM SCHEMATIC R3R4 lOOK68K 3 14 MASTERiiIC-iC2 SENSOR1/2 14538 R6 C R2t48~ 10K RiTRIMMER lOOK13 162 SLAVE5Ic-iCi SENSOR1/2 14538 1047 46 15-27K SEE TEXT R5 R20OUTPUT M ICROS WITCH 8SS3 HALL EFFECT SENSOR GROUND OUTPUT ences larger changes bigger ones Also initial sync turn slave servo would stop moving exact instant slave engine rpm matched master Functional description First lets look engine rpm sensing devices Inside tiny ceramic package Microswitch 8SS3 en tire signal processing system consisting Halleffect device magnetic detector amplifier Schmidt trigger open collector output tran sistor works very well very rugged crash tested totally uncomplicatedall takes make work power ground pull-up resistor Ri & R2 Now need way get constant pulse width independent rpm accomplished IC-I dual one-shot Next pulses master integrated network consist ing R6 C4 provides inputs differential integrator Al also minimum rpm detector A2 minimum rpm detector simple Schmidt trigger formed A2 R7 R8 R9 order keep system beingteased~ master rpm just coming range sync systems takes over R9 provides some feedback causes reference voltage pin 12 drop slightly master engine passes minimum rpm point deactivate sync system rpm must drop below point engaged about 1000 rpm provides measure safety keeps 34 Model Aviation ii necessary use snims modems cow T8C6 get proper magnet-to-sensor distance optimum performance Magnet canter should pass over button center sensor It looks like youre finished youve done good Job soldering back should work first time try system erratically turning off lower end rpm range As setup system will engage 2500 rpm will disengage 1500 rpm R8 R9 determine end points switching output A2 high low drives IC-3 quad analog switchthree sections used IC-3C together R19 acts inverter IC-3 pin 12 high pins 5 ii will go low providing switching slave servo signal normal receiver output sync system through IC-3 B actual rpm comparison done Op Amp Al Pulses IC-i both engines integrated compared output rises falls depending d ifference rpm way other signal cleaned up further RiO CS before being fed through Ri ito Ri 2 R13 Ru sets range output pulse width RI 2 Ri 3 set upper lower limits limits set two milli seconds will normally same range radio normally uses sync system engaged output pulse slave servo either comes directly servo sync system sync system pulse generated A4 Qi A3 A4 functions one-shot providing pulse independent throttle pulse width causes Qi discharge C8 ground As C8 begins charge output A3 pin will go low until voltage pin 3 exceeds voltage pin 2 Since voltage pin 2 determined rpm difference servo will respond direction forces rpm become equaL Q2 R2i R22 act low impedance inverter/buffer feeds pin 4 IC-3 analog gate system designed work systems high throttle theLONGER pulse width system set up like reverse outside wires transmitter stick pot recenter pot shaft use reversing switch transmitter has have negative pulse system just reverse connections pins 2 3 A3 can accomplished cutting copper runs installing two jumpers bottom PC board should done skilled technician however Resistors R5 R6 control response time sync system response time must longer time takes slave engine respond change throttle position As set up slow enough handle leaky crashproven Fox 25 engines have quick clean throttle response reduce R5 R6 22K 15K get too small slave throttle will overshoot just like underdamped servo sync system draws i66 mA operat ing normally 55 mils attributable Q2 R2 1 R22 Testing revealed certain servos did like having pulses less 35 volts tall since LM324 op-amp wont swing higher used transistor inverter low output impedance 1K comes price little current sync system output pulse swings virtually rail raiL use system effectively Believe should put weaker engine master position way whenever master sags richens up leans out slave will try track itkeeping thrust both engines same can use engines unequal displacement long weaker engine used master Since slave better-running engine start first Adjust properly check out point both master slave throttles Yd together Next throttle back Sync System SKETCH OF SYSTEM WIRING Master Sensor Master Servo Slave Sensor Slave Servo LIZ start master As soon engine running above 2500 rpm sync system wilJ take over prepare Always use helper flying twin-engine craftthose engines can get dangerous Adjust master best performance can expect reliable slave will merrily track right along What pleasure will pull up nice round loop have mis-track because uneven thrusd event either engine should quit youre still covered have immediate control over remaining engine master quits servos Yd together slave quits doesnt matter since master servo part system Just bring back throttle stick automatically control remaining engine no thinking required like have two separate throttles suggested method wiring cut up long aileron extension cables supplied radio systems manufacturer Since sync system trying maintain close match between slave master rpm imperative no slop slave engine throttle linkage less play linkage less overshoot orerror will sync system working system used chainsaw-type engines keep Hall-effect sensors far flywheel magnet possible Also would suggest use three four small MGlOi magnets evenly spaced spinner backplate will keep system its normal operating rpm range needing circuit changes gap between red face magnet bump SSS3 sensor should between 1/16 l inch reliable operation Giving credit credit due must give sincere thanks Don Langer Duncanville TX testing field work sync system As matter fact went far build twin-Stik just test system own expense Unfortunately ship met untimely end early development sync system Dons spirit undaunted said something about sun eyes Thanks wife being patient under standing Parts List Resistors R468K Ri R3 Ru Ri4 RiS R18 Ri9 R20lOOK R2i0Ktrimpot Ri3 39K R5 R627K R7200K RB39K R9i80K RiObK Ri6iK Ri747K R2i47K R22IK Integrated Circuits IC-iMCi 4538 Al A2 A3 A4LM324N IC-340i6 4066 Sensors Microswitch 8SS3 #101 MG-7 magnets Capacitors Ci C2 C8047 ufNPO C3 Continued page 126 October 1982 35 Heres size comparison 0 magnet sensor total weight system about 2I ozusefui small models author has flying RC 19 hIs 32 years test stand theres vintage Fox 29 used slave engine Fox 25 used master set giving three options Full now think Ill puffing separate battery pack just gyro motor use ESV between flights good idea have KDS digital ESV indicates voltage lighting bar-graph LED compact light rugged applies 320 mA load battery drifts less 05 VDC between 200F 1500F intend remove loading resistor mount permanently cabin wall Helicopter needs repetition previous mistake System now must aware Im delighted Circus Hobbies Apollo D6C-4SHM JRJ-100 Gyrosensor have economy servos worried about theyd stand up pounding big 61 engine 9 lb Helicopter gave good chance balancing rotating parts High Point balancer making sure pushrods snug fit servo arms bellcranks well being adequately supported eliminate vibratory bending Now after four gallons fuel about 16 hours operating time two servos have developed little slop gears think tolerable Having Main-Rotor Collective-Pitch trim control real convenience relationship between Throttle Collective wants change result changes atmospheric pressure temperature humidity well result changes wind velocity fuel use general bias trim Low direction decreased pitch-increased rotor rpm wind blows harder air hot/humid hence providing less lift given rpm calm cold dry air use higher pitch Nice U 1/20TH 5C4LE CCCUMENTATA9N D3S uim P40 CARD KITOF NOlABLE FA/RCH/LDS FULL COLOR EXACT REPRODUCTION $5000 NOWREMEMBER HOWoFAIRCHIL FC-1 #$ ONLYWELL THEY FLEW lt,SPeolI 044 Inolod. Oo,pon ooeNIogGEORGE /1 CLAFF FIN ModeIePO BOo 82 MO-N /3036 bolonce 4 eM 4 half 04o. Send TOCENTRAL SOU4A ROOOIII. MI 48588 GNIOUE NOSTALGIC GIFTRD $100-REFUNDED WITH ORDER OVER 50 CONSECUTIVE STARTS WITHOUT RECHARGING INTRODUCING THE NISTARTER TM PAT PENDING new completely revolutionary conce powerforgiow g m d planes helicopt andard plug g w ge up 1000 tim sideways inverted Fitings Uses HeadLock TM plu theplug propeller n c rr & instructions 90 day guarantee fte anything tails Inormal usage e air replace OI1Y $6 uno 1 full yeart SEE YOUR DEALERUS BANK CARDS OK COD See Dealer 13506 Glendundee K/U Herndon VA 22071 SERVICE703435-5805 U Roses have thorns Apollo has JR plugs make good contact either way tiny chamfers supposed key right way almost invisible except strong light safe way Ive found mate carefully observe color code wires case receiver put orange stripe down appropriate side socket cavity figure well have learn live themas weve learned live Krafts multicons transmitter uses NE5044 chip see RT June 1981 MA has plug-in AM radio frequency module receiver advertised being narrowband already has plug-in crys tal expect will testing NBFM narrow-band FM module possibly new receiveras soon FCC Report & Order published likely before read also possible receiver crystal change will necessary because Ive observed FM receivers respond equally well AM transmitters same frequency because RF systems call AM FM really arent either rather forms pulse modu lation Watch column see way comes out Circus Hobbies congratulated fine product study ads elsewhere issue Should chose buy system enumerated add Kalt Baron 20 appro priate engine can expect successful intro duction challenging field Helicopters about $500 Thats about half what cost 1979 theres bunch inflation since $500 figure close what youll spend comparable airplane Helicopters can fly smaller fields history model avia tion have lived through story ip creasingly expensive models decreasing field sizes used build Free Flight models dollar run miles chasing Detherm alizers came along shortened run some times Fields got smaller shifted Con trol Line RC became practical looked larger fields driving cars lot further process flew RC Now buildings fields cars smaller logical move return Control Line go Helicopters Because success assured todays highly developed machines predict resurgence interest Helicopters Apollo system will support Yes can use system fly airplanes race cars sail boats etcjust switch ATS OFF Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Sync System/Utasi Continued page 35 C4 C533 uftantalum C6 C7001 uf Semiconductors Qi Q22N3904 Dl 1N4 148 An etched drilled plated reflowed PC board available $1000 An assembled system less pigtails connectors available $5000 includes postage Both Jomar Products 2028 Knightsbridge Drive Cin cinnati OH 45244 writing advertisers mention read about Model Aviation 126 Model Aviation
Edition: Model Aviation - 1982/10
Page Numbers: 32, 33, 34, 35, 126
This Isan example kind model standsto benefitfrom system synchronize engine speed particular model Jerry Bugnis Piper Seneca ii photographed its takeoff roil 1978 AMA Nationals sync system keys weaker engine Have steered clear twin-engined planes because thought couldnt getthe revs two engines always match flight device may answer U Joseph G Utasi THERE ARE LOTS good reasons use sync system models 1 allows engines match rpm hassle matching engines linkages 2 Engines close unequai displacement can used together no performance penalty 3 keeps thrust equal under load conditions allow ing improved flight performance Now can finally build twin buying another engine engine sync system wont make bad engines run better wont keep engine shutting down will keep rpm both engines equal over normal operating range did choose design such system Perhaps its some deep desire carve niche myself record books modeldom could desire provide badly needed Essential development electronics project good test equip ment Pulse generator left sync system middle engine simulator right Tektronix 2213 scope background 32 Model Aviation say use enough powerthat boaro will tiy did serve its purpose dynamic teat bed device modeling fraternity Basically think main reason just because near thing time real engineering challenge Development system began winter 1979 snowbound hills Cincinnati Several prototypes built tested minimum success first engine rpm sensors problem Optical sensing tried proved unreliable variable lighting near prop hub Finally Hall-effect sensors used two small magnets mounted rear spinner backplate did trick second major problem cleanly sense master engine running some minimum speed required engage sync system After some embarrassingly compli cated circuitry simple effective circuit settled first approach sync detector phase-locked loopsort obvious solution engineering mentality After show its done full-scale twins approach came very close being workable slave engine would never settle out same rpm master would hunt like bad servo does turned out rpm could match BOTTOM VIEW OF PRINTED CIRCUIT BOARD ENGINE SYNC SYSTEM DRWN BY R OHARA COMPONENT PLACEMENT DIAGRAM sCALE 2 X 1 48 VOLTS SLAVE SENSOR GROUND 48 VOLTS MASTER SENSOR GROUND 4 0 0 0 R2R4cJRI4 RI OD~6O JG= CiD1 7 o R3 R5 A4A3@I1 jI UI c:: A21I RIO ~R8LJ ~RI3 R2I Q2 R7JR2 48 VOLTS MASTER INPUT GROUND 0 48 VOLTS SLAVE OUTPUT GROUND having same phase other words both engines would notfire exactly same instant Believe phase-locked loop would try correct changing throttle positon As can imagine resulted system could never satisfied back drawing board agalo last time around benefit over year thought testing suggestions close friend Don Langer new circuit design called differential integrator did trickit matched rpm ignored phase engine respect other also gave better overall sync responsesmall changes servo position small rpm differOctober 1982 33 PC board measures 1 /4 x 2 just about size Ace Bantam servo Finished board should enclosed small plastic case safety good fit some cyanoacrylate glue should used keep two magnets place spinner backplate EXPERIMENTAL TWIN ENGINE SYNC SYSTEM SCHEMATIC R3R4 lOOK68K 3 14 MASTERiiIC-iC2 SENSOR1/2 14538 R6 C R2t48~ 10K RiTRIMMER lOOK13 162 SLAVE5Ic-iCi SENSOR1/2 14538 1047 46 15-27K SEE TEXT R5 R20OUTPUT M ICROS WITCH 8SS3 HALL EFFECT SENSOR GROUND OUTPUT ences larger changes bigger ones Also initial sync turn slave servo would stop moving exact instant slave engine rpm matched master Functional description First lets look engine rpm sensing devices Inside tiny ceramic package Microswitch 8SS3 en tire signal processing system consisting Halleffect device magnetic detector amplifier Schmidt trigger open collector output tran sistor works very well very rugged crash tested totally uncomplicatedall takes make work power ground pull-up resistor Ri & R2 Now need way get constant pulse width independent rpm accomplished IC-I dual one-shot Next pulses master integrated network consist ing R6 C4 provides inputs differential integrator Al also minimum rpm detector A2 minimum rpm detector simple Schmidt trigger formed A2 R7 R8 R9 order keep system beingteased~ master rpm just coming range sync systems takes over R9 provides some feedback causes reference voltage pin 12 drop slightly master engine passes minimum rpm point deactivate sync system rpm must drop below point engaged about 1000 rpm provides measure safety keeps 34 Model Aviation ii necessary use snims modems cow T8C6 get proper magnet-to-sensor distance optimum performance Magnet canter should pass over button center sensor It looks like youre finished youve done good Job soldering back should work first time try system erratically turning off lower end rpm range As setup system will engage 2500 rpm will disengage 1500 rpm R8 R9 determine end points switching output A2 high low drives IC-3 quad analog switchthree sections used IC-3C together R19 acts inverter IC-3 pin 12 high pins 5 ii will go low providing switching slave servo signal normal receiver output sync system through IC-3 B actual rpm comparison done Op Amp Al Pulses IC-i both engines integrated compared output rises falls depending d ifference rpm way other signal cleaned up further RiO CS before being fed through Ri ito Ri 2 R13 Ru sets range output pulse width RI 2 Ri 3 set upper lower limits limits set two milli seconds will normally same range radio normally uses sync system engaged output pulse slave servo either comes directly servo sync system sync system pulse generated A4 Qi A3 A4 functions one-shot providing pulse independent throttle pulse width causes Qi discharge C8 ground As C8 begins charge output A3 pin will go low until voltage pin 3 exceeds voltage pin 2 Since voltage pin 2 determined rpm difference servo will respond direction forces rpm become equaL Q2 R2i R22 act low impedance inverter/buffer feeds pin 4 IC-3 analog gate system designed work systems high throttle theLONGER pulse width system set up like reverse outside wires transmitter stick pot recenter pot shaft use reversing switch transmitter has have negative pulse system just reverse connections pins 2 3 A3 can accomplished cutting copper runs installing two jumpers bottom PC board should done skilled technician however Resistors R5 R6 control response time sync system response time must longer time takes slave engine respond change throttle position As set up slow enough handle leaky crashproven Fox 25 engines have quick clean throttle response reduce R5 R6 22K 15K get too small slave throttle will overshoot just like underdamped servo sync system draws i66 mA operat ing normally 55 mils attributable Q2 R2 1 R22 Testing revealed certain servos did like having pulses less 35 volts tall since LM324 op-amp wont swing higher used transistor inverter low output impedance 1K comes price little current sync system output pulse swings virtually rail raiL use system effectively Believe should put weaker engine master position way whenever master sags richens up leans out slave will try track itkeeping thrust both engines same can use engines unequal displacement long weaker engine used master Since slave better-running engine start first Adjust properly check out point both master slave throttles Yd together Next throttle back Sync System SKETCH OF SYSTEM WIRING Master Sensor Master Servo Slave Sensor Slave Servo LIZ start master As soon engine running above 2500 rpm sync system wilJ take over prepare Always use helper flying twin-engine craftthose engines can get dangerous Adjust master best performance can expect reliable slave will merrily track right along What pleasure will pull up nice round loop have mis-track because uneven thrusd event either engine should quit youre still covered have immediate control over remaining engine master quits servos Yd together slave quits doesnt matter since master servo part system Just bring back throttle stick automatically control remaining engine no thinking required like have two separate throttles suggested method wiring cut up long aileron extension cables supplied radio systems manufacturer Since sync system trying maintain close match between slave master rpm imperative no slop slave engine throttle linkage less play linkage less overshoot orerror will sync system working system used chainsaw-type engines keep Hall-effect sensors far flywheel magnet possible Also would suggest use three four small MGlOi magnets evenly spaced spinner backplate will keep system its normal operating rpm range needing circuit changes gap between red face magnet bump SSS3 sensor should between 1/16 l inch reliable operation Giving credit credit due must give sincere thanks Don Langer Duncanville TX testing field work sync system As matter fact went far build twin-Stik just test system own expense Unfortunately ship met untimely end early development sync system Dons spirit undaunted said something about sun eyes Thanks wife being patient under standing Parts List Resistors R468K Ri R3 Ru Ri4 RiS R18 Ri9 R20lOOK R2i0Ktrimpot Ri3 39K R5 R627K R7200K RB39K R9i80K RiObK Ri6iK Ri747K R2i47K R22IK Integrated Circuits IC-iMCi 4538 Al A2 A3 A4LM324N IC-340i6 4066 Sensors Microswitch 8SS3 #101 MG-7 magnets Capacitors Ci C2 C8047 ufNPO C3 Continued page 126 October 1982 35 Heres size comparison 0 magnet sensor total weight system about 2I ozusefui small models author has flying RC 19 hIs 32 years test stand theres vintage Fox 29 used slave engine Fox 25 used master set giving three options Full now think Ill puffing separate battery pack just gyro motor use ESV between flights good idea have KDS digital ESV indicates voltage lighting bar-graph LED compact light rugged applies 320 mA load battery drifts less 05 VDC between 200F 1500F intend remove loading resistor mount permanently cabin wall Helicopter needs repetition previous mistake System now must aware Im delighted Circus Hobbies Apollo D6C-4SHM JRJ-100 Gyrosensor have economy servos worried about theyd stand up pounding big 61 engine 9 lb Helicopter gave good chance balancing rotating parts High Point balancer making sure pushrods snug fit servo arms bellcranks well being adequately supported eliminate vibratory bending Now after four gallons fuel about 16 hours operating time two servos have developed little slop gears think tolerable Having Main-Rotor Collective-Pitch trim control real convenience relationship between Throttle Collective wants change result changes atmospheric pressure temperature humidity well result changes wind velocity fuel use general bias trim Low direction decreased pitch-increased rotor rpm wind blows harder air hot/humid hence providing less lift given rpm calm cold dry air use higher pitch Nice U 1/20TH 5C4LE CCCUMENTATA9N D3S uim P40 CARD KITOF NOlABLE FA/RCH/LDS FULL COLOR EXACT REPRODUCTION $5000 NOWREMEMBER HOWoFAIRCHIL FC-1 #$ ONLYWELL THEY FLEW lt,SPeolI 044 Inolod. Oo,pon ooeNIogGEORGE /1 CLAFF FIN ModeIePO BOo 82 MO-N /3036 bolonce 4 eM 4 half 04o. Send TOCENTRAL SOU4A ROOOIII. MI 48588 GNIOUE NOSTALGIC GIFTRD $100-REFUNDED WITH ORDER OVER 50 CONSECUTIVE STARTS WITHOUT RECHARGING INTRODUCING THE NISTARTER TM PAT PENDING new completely revolutionary conce powerforgiow g m d planes helicopt andard plug g w ge up 1000 tim sideways inverted Fitings Uses HeadLock TM plu theplug propeller n c rr & instructions 90 day guarantee fte anything tails Inormal usage e air replace OI1Y $6 uno 1 full yeart SEE YOUR DEALERUS BANK CARDS OK COD See Dealer 13506 Glendundee K/U Herndon VA 22071 SERVICE703435-5805 U Roses have thorns Apollo has JR plugs make good contact either way tiny chamfers supposed key right way almost invisible except strong light safe way Ive found mate carefully observe color code wires case receiver put orange stripe down appropriate side socket cavity figure well have learn live themas weve learned live Krafts multicons transmitter uses NE5044 chip see RT June 1981 MA has plug-in AM radio frequency module receiver advertised being narrowband already has plug-in crys tal expect will testing NBFM narrow-band FM module possibly new receiveras soon FCC Report & Order published likely before read also possible receiver crystal change will necessary because Ive observed FM receivers respond equally well AM transmitters same frequency because RF systems call AM FM really arent either rather forms pulse modu lation Watch column see way comes out Circus Hobbies congratulated fine product study ads elsewhere issue Should chose buy system enumerated add Kalt Baron 20 appro priate engine can expect successful intro duction challenging field Helicopters about $500 Thats about half what cost 1979 theres bunch inflation since $500 figure close what youll spend comparable airplane Helicopters can fly smaller fields history model avia tion have lived through story ip creasingly expensive models decreasing field sizes used build Free Flight models dollar run miles chasing Detherm alizers came along shortened run some times Fields got smaller shifted Con trol Line RC became practical looked larger fields driving cars lot further process flew RC Now buildings fields cars smaller logical move return Control Line go Helicopters Because success assured todays highly developed machines predict resurgence interest Helicopters Apollo system will support Yes can use system fly airplanes race cars sail boats etcjust switch ATS OFF Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Sync System/Utasi Continued page 35 C4 C533 uftantalum C6 C7001 uf Semiconductors Qi Q22N3904 Dl 1N4 148 An etched drilled plated reflowed PC board available $1000 An assembled system less pigtails connectors available $5000 includes postage Both Jomar Products 2028 Knightsbridge Drive Cin cinnati OH 45244 writing advertisers mention read about Model Aviation 126 Model Aviation
Edition: Model Aviation - 1982/10
Page Numbers: 32, 33, 34, 35, 126
This Isan example kind model standsto benefitfrom system synchronize engine speed particular model Jerry Bugnis Piper Seneca ii photographed its takeoff roil 1978 AMA Nationals sync system keys weaker engine Have steered clear twin-engined planes because thought couldnt getthe revs two engines always match flight device may answer U Joseph G Utasi THERE ARE LOTS good reasons use sync system models 1 allows engines match rpm hassle matching engines linkages 2 Engines close unequai displacement can used together no performance penalty 3 keeps thrust equal under load conditions allow ing improved flight performance Now can finally build twin buying another engine engine sync system wont make bad engines run better wont keep engine shutting down will keep rpm both engines equal over normal operating range did choose design such system Perhaps its some deep desire carve niche myself record books modeldom could desire provide badly needed Essential development electronics project good test equip ment Pulse generator left sync system middle engine simulator right Tektronix 2213 scope background 32 Model Aviation say use enough powerthat boaro will tiy did serve its purpose dynamic teat bed device modeling fraternity Basically think main reason just because near thing time real engineering challenge Development system began winter 1979 snowbound hills Cincinnati Several prototypes built tested minimum success first engine rpm sensors problem Optical sensing tried proved unreliable variable lighting near prop hub Finally Hall-effect sensors used two small magnets mounted rear spinner backplate did trick second major problem cleanly sense master engine running some minimum speed required engage sync system After some embarrassingly compli cated circuitry simple effective circuit settled first approach sync detector phase-locked loopsort obvious solution engineering mentality After show its done full-scale twins approach came very close being workable slave engine would never settle out same rpm master would hunt like bad servo does turned out rpm could match BOTTOM VIEW OF PRINTED CIRCUIT BOARD ENGINE SYNC SYSTEM DRWN BY R OHARA COMPONENT PLACEMENT DIAGRAM sCALE 2 X 1 48 VOLTS SLAVE SENSOR GROUND 48 VOLTS MASTER SENSOR GROUND 4 0 0 0 R2R4cJRI4 RI OD~6O JG= CiD1 7 o R3 R5 A4A3@I1 jI UI c:: A21I RIO ~R8LJ ~RI3 R2I Q2 R7JR2 48 VOLTS MASTER INPUT GROUND 0 48 VOLTS SLAVE OUTPUT GROUND having same phase other words both engines would notfire exactly same instant Believe phase-locked loop would try correct changing throttle positon As can imagine resulted system could never satisfied back drawing board agalo last time around benefit over year thought testing suggestions close friend Don Langer new circuit design called differential integrator did trickit matched rpm ignored phase engine respect other also gave better overall sync responsesmall changes servo position small rpm differOctober 1982 33 PC board measures 1 /4 x 2 just about size Ace Bantam servo Finished board should enclosed small plastic case safety good fit some cyanoacrylate glue should used keep two magnets place spinner backplate EXPERIMENTAL TWIN ENGINE SYNC SYSTEM SCHEMATIC R3R4 lOOK68K 3 14 MASTERiiIC-iC2 SENSOR1/2 14538 R6 C R2t48~ 10K RiTRIMMER lOOK13 162 SLAVE5Ic-iCi SENSOR1/2 14538 1047 46 15-27K SEE TEXT R5 R20OUTPUT M ICROS WITCH 8SS3 HALL EFFECT SENSOR GROUND OUTPUT ences larger changes bigger ones Also initial sync turn slave servo would stop moving exact instant slave engine rpm matched master Functional description First lets look engine rpm sensing devices Inside tiny ceramic package Microswitch 8SS3 en tire signal processing system consisting Halleffect device magnetic detector amplifier Schmidt trigger open collector output tran sistor works very well very rugged crash tested totally uncomplicatedall takes make work power ground pull-up resistor Ri & R2 Now need way get constant pulse width independent rpm accomplished IC-I dual one-shot Next pulses master integrated network consist ing R6 C4 provides inputs differential integrator Al also minimum rpm detector A2 minimum rpm detector simple Schmidt trigger formed A2 R7 R8 R9 order keep system beingteased~ master rpm just coming range sync systems takes over R9 provides some feedback causes reference voltage pin 12 drop slightly master engine passes minimum rpm point deactivate sync system rpm must drop below point engaged about 1000 rpm provides measure safety keeps 34 Model Aviation ii necessary use snims modems cow T8C6 get proper magnet-to-sensor distance optimum performance Magnet canter should pass over button center sensor It looks like youre finished youve done good Job soldering back should work first time try system erratically turning off lower end rpm range As setup system will engage 2500 rpm will disengage 1500 rpm R8 R9 determine end points switching output A2 high low drives IC-3 quad analog switchthree sections used IC-3C together R19 acts inverter IC-3 pin 12 high pins 5 ii will go low providing switching slave servo signal normal receiver output sync system through IC-3 B actual rpm comparison done Op Amp Al Pulses IC-i both engines integrated compared output rises falls depending d ifference rpm way other signal cleaned up further RiO CS before being fed through Ri ito Ri 2 R13 Ru sets range output pulse width RI 2 Ri 3 set upper lower limits limits set two milli seconds will normally same range radio normally uses sync system engaged output pulse slave servo either comes directly servo sync system sync system pulse generated A4 Qi A3 A4 functions one-shot providing pulse independent throttle pulse width causes Qi discharge C8 ground As C8 begins charge output A3 pin will go low until voltage pin 3 exceeds voltage pin 2 Since voltage pin 2 determined rpm difference servo will respond direction forces rpm become equaL Q2 R2i R22 act low impedance inverter/buffer feeds pin 4 IC-3 analog gate system designed work systems high throttle theLONGER pulse width system set up like reverse outside wires transmitter stick pot recenter pot shaft use reversing switch transmitter has have negative pulse system just reverse connections pins 2 3 A3 can accomplished cutting copper runs installing two jumpers bottom PC board should done skilled technician however Resistors R5 R6 control response time sync system response time must longer time takes slave engine respond change throttle position As set up slow enough handle leaky crashproven Fox 25 engines have quick clean throttle response reduce R5 R6 22K 15K get too small slave throttle will overshoot just like underdamped servo sync system draws i66 mA operat ing normally 55 mils attributable Q2 R2 1 R22 Testing revealed certain servos did like having pulses less 35 volts tall since LM324 op-amp wont swing higher used transistor inverter low output impedance 1K comes price little current sync system output pulse swings virtually rail raiL use system effectively Believe should put weaker engine master position way whenever master sags richens up leans out slave will try track itkeeping thrust both engines same can use engines unequal displacement long weaker engine used master Since slave better-running engine start first Adjust properly check out point both master slave throttles Yd together Next throttle back Sync System SKETCH OF SYSTEM WIRING Master Sensor Master Servo Slave Sensor Slave Servo LIZ start master As soon engine running above 2500 rpm sync system wilJ take over prepare Always use helper flying twin-engine craftthose engines can get dangerous Adjust master best performance can expect reliable slave will merrily track right along What pleasure will pull up nice round loop have mis-track because uneven thrusd event either engine should quit youre still covered have immediate control over remaining engine master quits servos Yd together slave quits doesnt matter since master servo part system Just bring back throttle stick automatically control remaining engine no thinking required like have two separate throttles suggested method wiring cut up long aileron extension cables supplied radio systems manufacturer Since sync system trying maintain close match between slave master rpm imperative no slop slave engine throttle linkage less play linkage less overshoot orerror will sync system working system used chainsaw-type engines keep Hall-effect sensors far flywheel magnet possible Also would suggest use three four small MGlOi magnets evenly spaced spinner backplate will keep system its normal operating rpm range needing circuit changes gap between red face magnet bump SSS3 sensor should between 1/16 l inch reliable operation Giving credit credit due must give sincere thanks Don Langer Duncanville TX testing field work sync system As matter fact went far build twin-Stik just test system own expense Unfortunately ship met untimely end early development sync system Dons spirit undaunted said something about sun eyes Thanks wife being patient under standing Parts List Resistors R468K Ri R3 Ru Ri4 RiS R18 Ri9 R20lOOK R2i0Ktrimpot Ri3 39K R5 R627K R7200K RB39K R9i80K RiObK Ri6iK Ri747K R2i47K R22IK Integrated Circuits IC-iMCi 4538 Al A2 A3 A4LM324N IC-340i6 4066 Sensors Microswitch 8SS3 #101 MG-7 magnets Capacitors Ci C2 C8047 ufNPO C3 Continued page 126 October 1982 35 Heres size comparison 0 magnet sensor total weight system about 2I ozusefui small models author has flying RC 19 hIs 32 years test stand theres vintage Fox 29 used slave engine Fox 25 used master set giving three options Full now think Ill puffing separate battery pack just gyro motor use ESV between flights good idea have KDS digital ESV indicates voltage lighting bar-graph LED compact light rugged applies 320 mA load battery drifts less 05 VDC between 200F 1500F intend remove loading resistor mount permanently cabin wall Helicopter needs repetition previous mistake System now must aware Im delighted Circus Hobbies Apollo D6C-4SHM JRJ-100 Gyrosensor have economy servos worried about theyd stand up pounding big 61 engine 9 lb Helicopter gave good chance balancing rotating parts High Point balancer making sure pushrods snug fit servo arms bellcranks well being adequately supported eliminate vibratory bending Now after four gallons fuel about 16 hours operating time two servos have developed little slop gears think tolerable Having Main-Rotor Collective-Pitch trim control real convenience relationship between Throttle Collective wants change result changes atmospheric pressure temperature humidity well result changes wind velocity fuel use general bias trim Low direction decreased pitch-increased rotor rpm wind blows harder air hot/humid hence providing less lift given rpm calm cold dry air use higher pitch Nice U 1/20TH 5C4LE CCCUMENTATA9N D3S uim P40 CARD KITOF NOlABLE FA/RCH/LDS FULL COLOR EXACT REPRODUCTION $5000 NOWREMEMBER HOWoFAIRCHIL FC-1 #$ ONLYWELL THEY FLEW lt,SPeolI 044 Inolod. Oo,pon ooeNIogGEORGE /1 CLAFF FIN ModeIePO BOo 82 MO-N /3036 bolonce 4 eM 4 half 04o. Send TOCENTRAL SOU4A ROOOIII. MI 48588 GNIOUE NOSTALGIC GIFTRD $100-REFUNDED WITH ORDER OVER 50 CONSECUTIVE STARTS WITHOUT RECHARGING INTRODUCING THE NISTARTER TM PAT PENDING new completely revolutionary conce powerforgiow g m d planes helicopt andard plug g w ge up 1000 tim sideways inverted Fitings Uses HeadLock TM plu theplug propeller n c rr & instructions 90 day guarantee fte anything tails Inormal usage e air replace OI1Y $6 uno 1 full yeart SEE YOUR DEALERUS BANK CARDS OK COD See Dealer 13506 Glendundee K/U Herndon VA 22071 SERVICE703435-5805 U Roses have thorns Apollo has JR plugs make good contact either way tiny chamfers supposed key right way almost invisible except strong light safe way Ive found mate carefully observe color code wires case receiver put orange stripe down appropriate side socket cavity figure well have learn live themas weve learned live Krafts multicons transmitter uses NE5044 chip see RT June 1981 MA has plug-in AM radio frequency module receiver advertised being narrowband already has plug-in crys tal expect will testing NBFM narrow-band FM module possibly new receiveras soon FCC Report & Order published likely before read also possible receiver crystal change will necessary because Ive observed FM receivers respond equally well AM transmitters same frequency because RF systems call AM FM really arent either rather forms pulse modu lation Watch column see way comes out Circus Hobbies congratulated fine product study ads elsewhere issue Should chose buy system enumerated add Kalt Baron 20 appro priate engine can expect successful intro duction challenging field Helicopters about $500 Thats about half what cost 1979 theres bunch inflation since $500 figure close what youll spend comparable airplane Helicopters can fly smaller fields history model avia tion have lived through story ip creasingly expensive models decreasing field sizes used build Free Flight models dollar run miles chasing Detherm alizers came along shortened run some times Fields got smaller shifted Con trol Line RC became practical looked larger fields driving cars lot further process flew RC Now buildings fields cars smaller logical move return Control Line go Helicopters Because success assured todays highly developed machines predict resurgence interest Helicopters Apollo system will support Yes can use system fly airplanes race cars sail boats etcjust switch ATS OFF Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Sync System/Utasi Continued page 35 C4 C533 uftantalum C6 C7001 uf Semiconductors Qi Q22N3904 Dl 1N4 148 An etched drilled plated reflowed PC board available $1000 An assembled system less pigtails connectors available $5000 includes postage Both Jomar Products 2028 Knightsbridge Drive Cin cinnati OH 45244 writing advertisers mention read about Model Aviation 126 Model Aviation
Edition: Model Aviation - 1982/10
Page Numbers: 32, 33, 34, 35, 126
This Isan example kind model standsto benefitfrom system synchronize engine speed particular model Jerry Bugnis Piper Seneca ii photographed its takeoff roil 1978 AMA Nationals sync system keys weaker engine Have steered clear twin-engined planes because thought couldnt getthe revs two engines always match flight device may answer U Joseph G Utasi THERE ARE LOTS good reasons use sync system models 1 allows engines match rpm hassle matching engines linkages 2 Engines close unequai displacement can used together no performance penalty 3 keeps thrust equal under load conditions allow ing improved flight performance Now can finally build twin buying another engine engine sync system wont make bad engines run better wont keep engine shutting down will keep rpm both engines equal over normal operating range did choose design such system Perhaps its some deep desire carve niche myself record books modeldom could desire provide badly needed Essential development electronics project good test equip ment Pulse generator left sync system middle engine simulator right Tektronix 2213 scope background 32 Model Aviation say use enough powerthat boaro will tiy did serve its purpose dynamic teat bed device modeling fraternity Basically think main reason just because near thing time real engineering challenge Development system began winter 1979 snowbound hills Cincinnati Several prototypes built tested minimum success first engine rpm sensors problem Optical sensing tried proved unreliable variable lighting near prop hub Finally Hall-effect sensors used two small magnets mounted rear spinner backplate did trick second major problem cleanly sense master engine running some minimum speed required engage sync system After some embarrassingly compli cated circuitry simple effective circuit settled first approach sync detector phase-locked loopsort obvious solution engineering mentality After show its done full-scale twins approach came very close being workable slave engine would never settle out same rpm master would hunt like bad servo does turned out rpm could match BOTTOM VIEW OF PRINTED CIRCUIT BOARD ENGINE SYNC SYSTEM DRWN BY R OHARA COMPONENT PLACEMENT DIAGRAM sCALE 2 X 1 48 VOLTS SLAVE SENSOR GROUND 48 VOLTS MASTER SENSOR GROUND 4 0 0 0 R2R4cJRI4 RI OD~6O JG= CiD1 7 o R3 R5 A4A3@I1 jI UI c:: A21I RIO ~R8LJ ~RI3 R2I Q2 R7JR2 48 VOLTS MASTER INPUT GROUND 0 48 VOLTS SLAVE OUTPUT GROUND having same phase other words both engines would notfire exactly same instant Believe phase-locked loop would try correct changing throttle positon As can imagine resulted system could never satisfied back drawing board agalo last time around benefit over year thought testing suggestions close friend Don Langer new circuit design called differential integrator did trickit matched rpm ignored phase engine respect other also gave better overall sync responsesmall changes servo position small rpm differOctober 1982 33 PC board measures 1 /4 x 2 just about size Ace Bantam servo Finished board should enclosed small plastic case safety good fit some cyanoacrylate glue should used keep two magnets place spinner backplate EXPERIMENTAL TWIN ENGINE SYNC SYSTEM SCHEMATIC R3R4 lOOK68K 3 14 MASTERiiIC-iC2 SENSOR1/2 14538 R6 C R2t48~ 10K RiTRIMMER lOOK13 162 SLAVE5Ic-iCi SENSOR1/2 14538 1047 46 15-27K SEE TEXT R5 R20OUTPUT M ICROS WITCH 8SS3 HALL EFFECT SENSOR GROUND OUTPUT ences larger changes bigger ones Also initial sync turn slave servo would stop moving exact instant slave engine rpm matched master Functional description First lets look engine rpm sensing devices Inside tiny ceramic package Microswitch 8SS3 en tire signal processing system consisting Halleffect device magnetic detector amplifier Schmidt trigger open collector output tran sistor works very well very rugged crash tested totally uncomplicatedall takes make work power ground pull-up resistor Ri & R2 Now need way get constant pulse width independent rpm accomplished IC-I dual one-shot Next pulses master integrated network consist ing R6 C4 provides inputs differential integrator Al also minimum rpm detector A2 minimum rpm detector simple Schmidt trigger formed A2 R7 R8 R9 order keep system beingteased~ master rpm just coming range sync systems takes over R9 provides some feedback causes reference voltage pin 12 drop slightly master engine passes minimum rpm point deactivate sync system rpm must drop below point engaged about 1000 rpm provides measure safety keeps 34 Model Aviation ii necessary use snims modems cow T8C6 get proper magnet-to-sensor distance optimum performance Magnet canter should pass over button center sensor It looks like youre finished youve done good Job soldering back should work first time try system erratically turning off lower end rpm range As setup system will engage 2500 rpm will disengage 1500 rpm R8 R9 determine end points switching output A2 high low drives IC-3 quad analog switchthree sections used IC-3C together R19 acts inverter IC-3 pin 12 high pins 5 ii will go low providing switching slave servo signal normal receiver output sync system through IC-3 B actual rpm comparison done Op Amp Al Pulses IC-i both engines integrated compared output rises falls depending d ifference rpm way other signal cleaned up further RiO CS before being fed through Ri ito Ri 2 R13 Ru sets range output pulse width RI 2 Ri 3 set upper lower limits limits set two milli seconds will normally same range radio normally uses sync system engaged output pulse slave servo either comes directly servo sync system sync system pulse generated A4 Qi A3 A4 functions one-shot providing pulse independent throttle pulse width causes Qi discharge C8 ground As C8 begins charge output A3 pin will go low until voltage pin 3 exceeds voltage pin 2 Since voltage pin 2 determined rpm difference servo will respond direction forces rpm become equaL Q2 R2i R22 act low impedance inverter/buffer feeds pin 4 IC-3 analog gate system designed work systems high throttle theLONGER pulse width system set up like reverse outside wires transmitter stick pot recenter pot shaft use reversing switch transmitter has have negative pulse system just reverse connections pins 2 3 A3 can accomplished cutting copper runs installing two jumpers bottom PC board should done skilled technician however Resistors R5 R6 control response time sync system response time must longer time takes slave engine respond change throttle position As set up slow enough handle leaky crashproven Fox 25 engines have quick clean throttle response reduce R5 R6 22K 15K get too small slave throttle will overshoot just like underdamped servo sync system draws i66 mA operat ing normally 55 mils attributable Q2 R2 1 R22 Testing revealed certain servos did like having pulses less 35 volts tall since LM324 op-amp wont swing higher used transistor inverter low output impedance 1K comes price little current sync system output pulse swings virtually rail raiL use system effectively Believe should put weaker engine master position way whenever master sags richens up leans out slave will try track itkeeping thrust both engines same can use engines unequal displacement long weaker engine used master Since slave better-running engine start first Adjust properly check out point both master slave throttles Yd together Next throttle back Sync System SKETCH OF SYSTEM WIRING Master Sensor Master Servo Slave Sensor Slave Servo LIZ start master As soon engine running above 2500 rpm sync system wilJ take over prepare Always use helper flying twin-engine craftthose engines can get dangerous Adjust master best performance can expect reliable slave will merrily track right along What pleasure will pull up nice round loop have mis-track because uneven thrusd event either engine should quit youre still covered have immediate control over remaining engine master quits servos Yd together slave quits doesnt matter since master servo part system Just bring back throttle stick automatically control remaining engine no thinking required like have two separate throttles suggested method wiring cut up long aileron extension cables supplied radio systems manufacturer Since sync system trying maintain close match between slave master rpm imperative no slop slave engine throttle linkage less play linkage less overshoot orerror will sync system working system used chainsaw-type engines keep Hall-effect sensors far flywheel magnet possible Also would suggest use three four small MGlOi magnets evenly spaced spinner backplate will keep system its normal operating rpm range needing circuit changes gap between red face magnet bump SSS3 sensor should between 1/16 l inch reliable operation Giving credit credit due must give sincere thanks Don Langer Duncanville TX testing field work sync system As matter fact went far build twin-Stik just test system own expense Unfortunately ship met untimely end early development sync system Dons spirit undaunted said something about sun eyes Thanks wife being patient under standing Parts List Resistors R468K Ri R3 Ru Ri4 RiS R18 Ri9 R20lOOK R2i0Ktrimpot Ri3 39K R5 R627K R7200K RB39K R9i80K RiObK Ri6iK Ri747K R2i47K R22IK Integrated Circuits IC-iMCi 4538 Al A2 A3 A4LM324N IC-340i6 4066 Sensors Microswitch 8SS3 #101 MG-7 magnets Capacitors Ci C2 C8047 ufNPO C3 Continued page 126 October 1982 35 Heres size comparison 0 magnet sensor total weight system about 2I ozusefui small models author has flying RC 19 hIs 32 years test stand theres vintage Fox 29 used slave engine Fox 25 used master set giving three options Full now think Ill puffing separate battery pack just gyro motor use ESV between flights good idea have KDS digital ESV indicates voltage lighting bar-graph LED compact light rugged applies 320 mA load battery drifts less 05 VDC between 200F 1500F intend remove loading resistor mount permanently cabin wall Helicopter needs repetition previous mistake System now must aware Im delighted Circus Hobbies Apollo D6C-4SHM JRJ-100 Gyrosensor have economy servos worried about theyd stand up pounding big 61 engine 9 lb Helicopter gave good chance balancing rotating parts High Point balancer making sure pushrods snug fit servo arms bellcranks well being adequately supported eliminate vibratory bending Now after four gallons fuel about 16 hours operating time two servos have developed little slop gears think tolerable Having Main-Rotor Collective-Pitch trim control real convenience relationship between Throttle Collective wants change result changes atmospheric pressure temperature humidity well result changes wind velocity fuel use general bias trim Low direction decreased pitch-increased rotor rpm wind blows harder air hot/humid hence providing less lift given rpm calm cold dry air use higher pitch Nice U 1/20TH 5C4LE CCCUMENTATA9N D3S uim P40 CARD KITOF NOlABLE FA/RCH/LDS FULL COLOR EXACT REPRODUCTION $5000 NOWREMEMBER HOWoFAIRCHIL FC-1 #$ ONLYWELL THEY FLEW lt,SPeolI 044 Inolod. Oo,pon ooeNIogGEORGE /1 CLAFF FIN ModeIePO BOo 82 MO-N /3036 bolonce 4 eM 4 half 04o. Send TOCENTRAL SOU4A ROOOIII. MI 48588 GNIOUE NOSTALGIC GIFTRD $100-REFUNDED WITH ORDER OVER 50 CONSECUTIVE STARTS WITHOUT RECHARGING INTRODUCING THE NISTARTER TM PAT PENDING new completely revolutionary conce powerforgiow g m d planes helicopt andard plug g w ge up 1000 tim sideways inverted Fitings Uses HeadLock TM plu theplug propeller n c rr & instructions 90 day guarantee fte anything tails Inormal usage e air replace OI1Y $6 uno 1 full yeart SEE YOUR DEALERUS BANK CARDS OK COD See Dealer 13506 Glendundee K/U Herndon VA 22071 SERVICE703435-5805 U Roses have thorns Apollo has JR plugs make good contact either way tiny chamfers supposed key right way almost invisible except strong light safe way Ive found mate carefully observe color code wires case receiver put orange stripe down appropriate side socket cavity figure well have learn live themas weve learned live Krafts multicons transmitter uses NE5044 chip see RT June 1981 MA has plug-in AM radio frequency module receiver advertised being narrowband already has plug-in crys tal expect will testing NBFM narrow-band FM module possibly new receiveras soon FCC Report & Order published likely before read also possible receiver crystal change will necessary because Ive observed FM receivers respond equally well AM transmitters same frequency because RF systems call AM FM really arent either rather forms pulse modu lation Watch column see way comes out Circus Hobbies congratulated fine product study ads elsewhere issue Should chose buy system enumerated add Kalt Baron 20 appro priate engine can expect successful intro duction challenging field Helicopters about $500 Thats about half what cost 1979 theres bunch inflation since $500 figure close what youll spend comparable airplane Helicopters can fly smaller fields history model avia tion have lived through story ip creasingly expensive models decreasing field sizes used build Free Flight models dollar run miles chasing Detherm alizers came along shortened run some times Fields got smaller shifted Con trol Line RC became practical looked larger fields driving cars lot further process flew RC Now buildings fields cars smaller logical move return Control Line go Helicopters Because success assured todays highly developed machines predict resurgence interest Helicopters Apollo system will support Yes can use system fly airplanes race cars sail boats etcjust switch ATS OFF Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Sync System/Utasi Continued page 35 C4 C533 uftantalum C6 C7001 uf Semiconductors Qi Q22N3904 Dl 1N4 148 An etched drilled plated reflowed PC board available $1000 An assembled system less pigtails connectors available $5000 includes postage Both Jomar Products 2028 Knightsbridge Drive Cin cinnati OH 45244 writing advertisers mention read about Model Aviation 126 Model Aviation
Edition: Model Aviation - 1982/10
Page Numbers: 32, 33, 34, 35, 126
This Isan example kind model standsto benefitfrom system synchronize engine speed particular model Jerry Bugnis Piper Seneca ii photographed its takeoff roil 1978 AMA Nationals sync system keys weaker engine Have steered clear twin-engined planes because thought couldnt getthe revs two engines always match flight device may answer U Joseph G Utasi THERE ARE LOTS good reasons use sync system models 1 allows engines match rpm hassle matching engines linkages 2 Engines close unequai displacement can used together no performance penalty 3 keeps thrust equal under load conditions allow ing improved flight performance Now can finally build twin buying another engine engine sync system wont make bad engines run better wont keep engine shutting down will keep rpm both engines equal over normal operating range did choose design such system Perhaps its some deep desire carve niche myself record books modeldom could desire provide badly needed Essential development electronics project good test equip ment Pulse generator left sync system middle engine simulator right Tektronix 2213 scope background 32 Model Aviation say use enough powerthat boaro will tiy did serve its purpose dynamic teat bed device modeling fraternity Basically think main reason just because near thing time real engineering challenge Development system began winter 1979 snowbound hills Cincinnati Several prototypes built tested minimum success first engine rpm sensors problem Optical sensing tried proved unreliable variable lighting near prop hub Finally Hall-effect sensors used two small magnets mounted rear spinner backplate did trick second major problem cleanly sense master engine running some minimum speed required engage sync system After some embarrassingly compli cated circuitry simple effective circuit settled first approach sync detector phase-locked loopsort obvious solution engineering mentality After show its done full-scale twins approach came very close being workable slave engine would never settle out same rpm master would hunt like bad servo does turned out rpm could match BOTTOM VIEW OF PRINTED CIRCUIT BOARD ENGINE SYNC SYSTEM DRWN BY R OHARA COMPONENT PLACEMENT DIAGRAM sCALE 2 X 1 48 VOLTS SLAVE SENSOR GROUND 48 VOLTS MASTER SENSOR GROUND 4 0 0 0 R2R4cJRI4 RI OD~6O JG= CiD1 7 o R3 R5 A4A3@I1 jI UI c:: A21I RIO ~R8LJ ~RI3 R2I Q2 R7JR2 48 VOLTS MASTER INPUT GROUND 0 48 VOLTS SLAVE OUTPUT GROUND having same phase other words both engines would notfire exactly same instant Believe phase-locked loop would try correct changing throttle positon As can imagine resulted system could never satisfied back drawing board agalo last time around benefit over year thought testing suggestions close friend Don Langer new circuit design called differential integrator did trickit matched rpm ignored phase engine respect other also gave better overall sync responsesmall changes servo position small rpm differOctober 1982 33 PC board measures 1 /4 x 2 just about size Ace Bantam servo Finished board should enclosed small plastic case safety good fit some cyanoacrylate glue should used keep two magnets place spinner backplate EXPERIMENTAL TWIN ENGINE SYNC SYSTEM SCHEMATIC R3R4 lOOK68K 3 14 MASTERiiIC-iC2 SENSOR1/2 14538 R6 C R2t48~ 10K RiTRIMMER lOOK13 162 SLAVE5Ic-iCi SENSOR1/2 14538 1047 46 15-27K SEE TEXT R5 R20OUTPUT M ICROS WITCH 8SS3 HALL EFFECT SENSOR GROUND OUTPUT ences larger changes bigger ones Also initial sync turn slave servo would stop moving exact instant slave engine rpm matched master Functional description First lets look engine rpm sensing devices Inside tiny ceramic package Microswitch 8SS3 en tire signal processing system consisting Halleffect device magnetic detector amplifier Schmidt trigger open collector output tran sistor works very well very rugged crash tested totally uncomplicatedall takes make work power ground pull-up resistor Ri & R2 Now need way get constant pulse width independent rpm accomplished IC-I dual one-shot Next pulses master integrated network consist ing R6 C4 provides inputs differential integrator Al also minimum rpm detector A2 minimum rpm detector simple Schmidt trigger formed A2 R7 R8 R9 order keep system beingteased~ master rpm just coming range sync systems takes over R9 provides some feedback causes reference voltage pin 12 drop slightly master engine passes minimum rpm point deactivate sync system rpm must drop below point engaged about 1000 rpm provides measure safety keeps 34 Model Aviation ii necessary use snims modems cow T8C6 get proper magnet-to-sensor distance optimum performance Magnet canter should pass over button center sensor It looks like youre finished youve done good Job soldering back should work first time try system erratically turning off lower end rpm range As setup system will engage 2500 rpm will disengage 1500 rpm R8 R9 determine end points switching output A2 high low drives IC-3 quad analog switchthree sections used IC-3C together R19 acts inverter IC-3 pin 12 high pins 5 ii will go low providing switching slave servo signal normal receiver output sync system through IC-3 B actual rpm comparison done Op Amp Al Pulses IC-i both engines integrated compared output rises falls depending d ifference rpm way other signal cleaned up further RiO CS before being fed through Ri ito Ri 2 R13 Ru sets range output pulse width RI 2 Ri 3 set upper lower limits limits set two milli seconds will normally same range radio normally uses sync system engaged output pulse slave servo either comes directly servo sync system sync system pulse generated A4 Qi A3 A4 functions one-shot providing pulse independent throttle pulse width causes Qi discharge C8 ground As C8 begins charge output A3 pin will go low until voltage pin 3 exceeds voltage pin 2 Since voltage pin 2 determined rpm difference servo will respond direction forces rpm become equaL Q2 R2i R22 act low impedance inverter/buffer feeds pin 4 IC-3 analog gate system designed work systems high throttle theLONGER pulse width system set up like reverse outside wires transmitter stick pot recenter pot shaft use reversing switch transmitter has have negative pulse system just reverse connections pins 2 3 A3 can accomplished cutting copper runs installing two jumpers bottom PC board should done skilled technician however Resistors R5 R6 control response time sync system response time must longer time takes slave engine respond change throttle position As set up slow enough handle leaky crashproven Fox 25 engines have quick clean throttle response reduce R5 R6 22K 15K get too small slave throttle will overshoot just like underdamped servo sync system draws i66 mA operat ing normally 55 mils attributable Q2 R2 1 R22 Testing revealed certain servos did like having pulses less 35 volts tall since LM324 op-amp wont swing higher used transistor inverter low output impedance 1K comes price little current sync system output pulse swings virtually rail raiL use system effectively Believe should put weaker engine master position way whenever master sags richens up leans out slave will try track itkeeping thrust both engines same can use engines unequal displacement long weaker engine used master Since slave better-running engine start first Adjust properly check out point both master slave throttles Yd together Next throttle back Sync System SKETCH OF SYSTEM WIRING Master Sensor Master Servo Slave Sensor Slave Servo LIZ start master As soon engine running above 2500 rpm sync system wilJ take over prepare Always use helper flying twin-engine craftthose engines can get dangerous Adjust master best performance can expect reliable slave will merrily track right along What pleasure will pull up nice round loop have mis-track because uneven thrusd event either engine should quit youre still covered have immediate control over remaining engine master quits servos Yd together slave quits doesnt matter since master servo part system Just bring back throttle stick automatically control remaining engine no thinking required like have two separate throttles suggested method wiring cut up long aileron extension cables supplied radio systems manufacturer Since sync system trying maintain close match between slave master rpm imperative no slop slave engine throttle linkage less play linkage less overshoot orerror will sync system working system used chainsaw-type engines keep Hall-effect sensors far flywheel magnet possible Also would suggest use three four small MGlOi magnets evenly spaced spinner backplate will keep system its normal operating rpm range needing circuit changes gap between red face magnet bump SSS3 sensor should between 1/16 l inch reliable operation Giving credit credit due must give sincere thanks Don Langer Duncanville TX testing field work sync system As matter fact went far build twin-Stik just test system own expense Unfortunately ship met untimely end early development sync system Dons spirit undaunted said something about sun eyes Thanks wife being patient under standing Parts List Resistors R468K Ri R3 Ru Ri4 RiS R18 Ri9 R20lOOK R2i0Ktrimpot Ri3 39K R5 R627K R7200K RB39K R9i80K RiObK Ri6iK Ri747K R2i47K R22IK Integrated Circuits IC-iMCi 4538 Al A2 A3 A4LM324N IC-340i6 4066 Sensors Microswitch 8SS3 #101 MG-7 magnets Capacitors Ci C2 C8047 ufNPO C3 Continued page 126 October 1982 35 Heres size comparison 0 magnet sensor total weight system about 2I ozusefui small models author has flying RC 19 hIs 32 years test stand theres vintage Fox 29 used slave engine Fox 25 used master set giving three options Full now think Ill puffing separate battery pack just gyro motor use ESV between flights good idea have KDS digital ESV indicates voltage lighting bar-graph LED compact light rugged applies 320 mA load battery drifts less 05 VDC between 200F 1500F intend remove loading resistor mount permanently cabin wall Helicopter needs repetition previous mistake System now must aware Im delighted Circus Hobbies Apollo D6C-4SHM JRJ-100 Gyrosensor have economy servos worried about theyd stand up pounding big 61 engine 9 lb Helicopter gave good chance balancing rotating parts High Point balancer making sure pushrods snug fit servo arms bellcranks well being adequately supported eliminate vibratory bending Now after four gallons fuel about 16 hours operating time two servos have developed little slop gears think tolerable Having Main-Rotor Collective-Pitch trim control real convenience relationship between Throttle Collective wants change result changes atmospheric pressure temperature humidity well result changes wind velocity fuel use general bias trim Low direction decreased pitch-increased rotor rpm wind blows harder air hot/humid hence providing less lift given rpm calm cold dry air use higher pitch Nice U 1/20TH 5C4LE CCCUMENTATA9N D3S uim P40 CARD KITOF NOlABLE FA/RCH/LDS FULL COLOR EXACT REPRODUCTION $5000 NOWREMEMBER HOWoFAIRCHIL FC-1 #$ ONLYWELL THEY FLEW lt,SPeolI 044 Inolod. Oo,pon ooeNIogGEORGE /1 CLAFF FIN ModeIePO BOo 82 MO-N /3036 bolonce 4 eM 4 half 04o. Send TOCENTRAL SOU4A ROOOIII. MI 48588 GNIOUE NOSTALGIC GIFTRD $100-REFUNDED WITH ORDER OVER 50 CONSECUTIVE STARTS WITHOUT RECHARGING INTRODUCING THE NISTARTER TM PAT PENDING new completely revolutionary conce powerforgiow g m d planes helicopt andard plug g w ge up 1000 tim sideways inverted Fitings Uses HeadLock TM plu theplug propeller n c rr & instructions 90 day guarantee fte anything tails Inormal usage e air replace OI1Y $6 uno 1 full yeart SEE YOUR DEALERUS BANK CARDS OK COD See Dealer 13506 Glendundee K/U Herndon VA 22071 SERVICE703435-5805 U Roses have thorns Apollo has JR plugs make good contact either way tiny chamfers supposed key right way almost invisible except strong light safe way Ive found mate carefully observe color code wires case receiver put orange stripe down appropriate side socket cavity figure well have learn live themas weve learned live Krafts multicons transmitter uses NE5044 chip see RT June 1981 MA has plug-in AM radio frequency module receiver advertised being narrowband already has plug-in crys tal expect will testing NBFM narrow-band FM module possibly new receiveras soon FCC Report & Order published likely before read also possible receiver crystal change will necessary because Ive observed FM receivers respond equally well AM transmitters same frequency because RF systems call AM FM really arent either rather forms pulse modu lation Watch column see way comes out Circus Hobbies congratulated fine product study ads elsewhere issue Should chose buy system enumerated add Kalt Baron 20 appro priate engine can expect successful intro duction challenging field Helicopters about $500 Thats about half what cost 1979 theres bunch inflation since $500 figure close what youll spend comparable airplane Helicopters can fly smaller fields history model avia tion have lived through story ip creasingly expensive models decreasing field sizes used build Free Flight models dollar run miles chasing Detherm alizers came along shortened run some times Fields got smaller shifted Con trol Line RC became practical looked larger fields driving cars lot further process flew RC Now buildings fields cars smaller logical move return Control Line go Helicopters Because success assured todays highly developed machines predict resurgence interest Helicopters Apollo system will support Yes can use system fly airplanes race cars sail boats etcjust switch ATS OFF Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Sync System/Utasi Continued page 35 C4 C533 uftantalum C6 C7001 uf Semiconductors Qi Q22N3904 Dl 1N4 148 An etched drilled plated reflowed PC board available $1000 An assembled system less pigtails connectors available $5000 includes postage Both Jomar Products 2028 Knightsbridge Drive Cin cinnati OH 45244 writing advertisers mention read about Model Aviation 126 Model Aviation