Pulse ComparatorStretcherDriverOutputM Ge THE MAIL initial columns has extensive Thanks support giving idea things interest mail has will answered personally consider general interest will answered pages MA Surprisingly enough majority questions have about batteries have past about servos Dick Lehmann Wasau WI condensed notes letter Please write column discussing servos work What differences between different models some much expensive others Maybe read wrong magazines have yet see good article servos Well Dick article servos coming up Cost little doubt exception items marketed bought show-off appeal quality reliability expensive can get TimexTM $10 Rolex[M $ 10000both tell time can buy Fuji camera $2995 NikoniM $2995both take pictures differences same applies servos costly servos assembled using better grade electronic components greater mechanical precision common-type ferrite motor will cost less $10 motor cureless servo will $30 plugs money-saver silver-coloredprobably tin-plated better-class servos gold-plated dont know exact difference cost latter expensive printed circuit board cheapie will thin phenolic subject bowing little shock read crash resistance better boards fiberglass-reinforced epoxy usually twice thick metal gears expensivegenerally five six times much probably get picture Now little bit theory digestible level Servos commanded length Block diagram servo amplifiers inner workings Most circuitry contained control pulse varies between single IC Integrated Circuitminimal external componentsio 20 inS centering 15 inS 66 Model Aviation oy Marez Generally regarded necessary evil servos complex sophisticated partner modern Radio Control systems Gear train normally has five gears quality look reinforced material shiny thickness ball bearings Input Reference Pulse Generator Feedback Potentiometer SERVO FUNCTION 15 MS 1020 MSMS An RC Radio Control servo very sophisticated electromechanical device stage has mate others perfectly cause deterioration final results can consider servo three separate entities motor gear train electronics ultimate job servo convert electrical energy battery physical energy motor last link chain its quality determines power output efficiency servo Let engineers worry about formulas involved just accept current consumed greater muscle power available servo arm common motor ferrite permanent magnet DC Direct Current ie battery current motor Its moving part steel armature wrapped turns wire rotating between pair magnets RC servos three- fivepole motors referring number windings used five-pole motor runs smoother full speed will develop slightly power however important remember servo motor seldom runs period time full speed armature heavy takes time pick up speed wants coast once power cut off coreless motor can thought being made inside-out armature actually coil wrapped wire steel center magnets fixed within armature spins around advantages lighter armature speeds up faster stops quicker coreless motor far precise respects therefore costs gear train required couple motor shaft output arm required speed gear ratio extremely high300-400 1 designed result powerful servo acts faster As things mechanical no freebies given motor input voltage can have either both gear train has job driving pot potentiometera variable resistor shaft rotates step servo output job provide feedback signal telling servo stop way does another quality costaffecting feature earlier some current cheapies pot shaft connected servo output works until heavy load placed output can place enough pressure pot shaft upset its function causing erratic servo action better way indirect servo drive requires another gear connected output thus pressure applied arm will transferred pot shaft Ball bearings ball-bearingsupported shaft should operate truer freer kind solid bushing servos used support output gear shaftsome bearing top better ones also base Its another reason costlier servos will result superior performance Now electronicsthe so-called amplifier much simple amplifier cheapest ones quite involved Regardless cost basically same thing process information generated transmitter inputs drive motor required direction degree follow inputs process called PWM Pulse Width Modulation no such thing PCM Pulse Code Modulation servo PCM system ultimate servo-driving command has changed PWM forget about PPM Pulse Position Modulation term incorrect regardless its common use know better non-PCM system operates PWM another story width Pulse Width control signal tells servo what frequency standard 10-20 mS millisecond /iooo second-long pulse centering 15 inS other words transmitter generating string such pulsesone channelthat processed directed proper servo receiver stick neutral servo neutral Moving stick increases decreases pulse length servo will operate appropriate direction Operating transmitter servo reverse reverses signal changes stick moved Within amplifier incoming signal first applied comparator might expect name compares its length internal 15 mS reference difference read fed pulse stretcher also does what its name implies Next comes some driver circuitry based whether pulse length now less 15 feeds current motor proper polarity make turn desired direction motor turns Whoa Remember gear-driven feedback pot Its function adjust output reference generator match incoming pulse match difference length canceled out motor commanded stop servo will stay until next stick movement process starts again proper direction Enjoy RELMILE S-L-G-O-W Idle PLUS. 457 S4FE studs Single Twin-cylinders Twin engines WO Interference Works Rxs Light Less 35 grams Ultra-simple installation E DiLl II mXLFJL1 o No messy adJustments Computer-accurate neutral o No Jitter U No Drift Neutral Sh4fis temperature changes U Fuelproof Vibration proof Encapsulated space-age epoxy WUKI SUI4jAJL 31185 Schoolcraft Livania Ml 48150 Website httpI/wwwelecfrodynamcOm 1-800-337-1638 Orders 1-734-422 5420 VISA Fax 1734-4225338 September 1999 67 line up yourtar long slow approach. Theres no tear tiameouts GlowLites onboardi doesnt Ret better this. EDR-106 P Snrnn 7niriir SEER tinan 1-2-3 Plug jeer serve late Pr Serve Reverser Plug Pr Serve Reverser late peer Ra Wew Peere done E xclusively Canopies Two sizes Small 3/16 47mm Large 1/4 64mm Canopy Trim Fourmost Canopy Trim flexible black vinyl strip preformed make perfect mounting trim canopies 4 Feet 122 meters per package Because the Canopy Trims unique shape flexibility will contour both flat round fuselages Canopy Trim secures canopy place well providing realistic black outline Canopy Trim may easily installed just razor blade CA adhesive small Product No 139 Large Product No 140 Price $3 95 FOURMOST PRODUCTS Look other great products Fourmost nearest hobby dealer direct orders include $4 50 Shipping 4040 24th Avenue Forest Grove OR 97116 Phone/Fax 503 357 2732 internet www tourmost com l rcooney@ntrnet Makes starting easier sater Keeps GLOWDRnRglow plug hotjusiwhev yourerrgine needs Connects hetween throttle servo receiver reversibie seiectable ts unit can drive two stow piogs turns 00 troosmiser ott t00% electronic made USA Compotihie AM FM PCM roSin systems Low power consumption comes hookup wire Less radio connector pownr net plug clip Sloe t 7 0 t 2 0 04 Weight 04. . Port No SA $3495 $3750 wconnector $4485 WIradio systems Low power consumption Less connector & piog cup CALL corepiete singie twioengiee andradio power connectors Size tb o 505 n 05 Weight t 2 no twiocpiinder systemsPart No ou $3495 $3780 radio connector Gives older DuAL-Ouwur SER voRs VERSUR ruAss ability reverse direction hems operation installations setups easier convenient Provides both normal reversed output use Y connector makes spilt elevator two-servo ailerons double-servo rudder installation super-eahy t 00% electronic no setup taoslust nennect torget Made USA works AM FM PCM radio systems Ultra-low power consumption Less radio connector Sloe t 0000 004 Weight 025 Part No 2U $2495 $2750 comptete Wiconflector Complete vyvtemv other producto avaitahte etanes coca Sooth Catt write fan detaith Gives standard radios ability . vtaiis ilaps spoilers aileronlrudder coupling busy setup installation Rugged micraprocessorbased design 100% electronic br high reliability Simply connect miver between eemos receiver Features two mioing modes individual semo reversing tour digerent mising rates teatures allow tailor miser needs ot model Will overdrine servos options selected simple switches Made USA designed tar AM FM PCM radio systems very low power consumption Less radio connectors Sloe t ha 00 004 Weight 025 PartNo OA $3055 $3085 compiete wlcoooectors numerous points performance can deteriorated Motor first poor motor poor servo Gear slop obvious including pot drive amplifier have deal voltage temperature variations both can affect its operation can read unwanted movement servo arm wheel Especially higher-power servos current-handling capacity drive circuitry critical Ratings Consumers given speed torque ratings servo makers can understand speed fractions second though some cases stated time 900 movement others 600 such instances reported time same different servos moving 90 faster Torque Reported ounce-inches ie its measure force generated end one-inch arm generally published ounce/inches ounces divided inches However should ounceinches ounces relative inches However reported higher torque rating work servo capable doing another two important often unrecognized facts First energy produced servo free comes battery Faster heavier airplanes use battery current Sloppy installations use battery current does friction anywhere control linkage stalled servo such mechanically bottoms often seen throttle nose wheel steering installations can fatal Second servo does produce rated torque time operates maximum torque possible What does produce determined load applied amount control surface deflection commanded scratches surface start toward better understanding what makes servos work flying serious airplanes save money wherever can servos dont need fastest powerful servo expensive controls since throttles smoke valves etc life-threatening can generally operated lessthan-optimum servos Use better servos primary flight controls Super Servos h la JR Microprocessor servos latest developments interchangeability much will have wait until next time odel Aviation ELAND MODEL & SUPPLY CO P0 Box 55962AA Indianapolis IN 46205-0962 4I LI~Phone 317 257-7878 Fax 317 257-7877 MODEL ENGINEERS SINCE 1919 Choose Over 1100 Plans Over 100 Aircraft Manufacturers Represented Five Aviation Eras Spanned Seven Scales Available 48-page Catalog- $500 $800 Foreign P 0 Box 3129 US CHRISTi TX 78463-3129 Add $550 S&H Genres torveson 0 Cuseonee Sconce Sbt St 4-0543 5endt TX Renidanto Honey M-F ttuobro Cnsveu FAX &Arvcv Hvinv l3btl Std5843 FREU odd 7575% isorosce booiL & Tucesicut Snurn pmetek@uwbeltnetCatalogsaiestao
Edition: Model Aviation - 1999/09
Page Numbers: 66, 67, 68
Pulse ComparatorStretcherDriverOutputM Ge THE MAIL initial columns has extensive Thanks support giving idea things interest mail has will answered personally consider general interest will answered pages MA Surprisingly enough majority questions have about batteries have past about servos Dick Lehmann Wasau WI condensed notes letter Please write column discussing servos work What differences between different models some much expensive others Maybe read wrong magazines have yet see good article servos Well Dick article servos coming up Cost little doubt exception items marketed bought show-off appeal quality reliability expensive can get TimexTM $10 Rolex[M $ 10000both tell time can buy Fuji camera $2995 NikoniM $2995both take pictures differences same applies servos costly servos assembled using better grade electronic components greater mechanical precision common-type ferrite motor will cost less $10 motor cureless servo will $30 plugs money-saver silver-coloredprobably tin-plated better-class servos gold-plated dont know exact difference cost latter expensive printed circuit board cheapie will thin phenolic subject bowing little shock read crash resistance better boards fiberglass-reinforced epoxy usually twice thick metal gears expensivegenerally five six times much probably get picture Now little bit theory digestible level Servos commanded length Block diagram servo amplifiers inner workings Most circuitry contained control pulse varies between single IC Integrated Circuitminimal external componentsio 20 inS centering 15 inS 66 Model Aviation oy Marez Generally regarded necessary evil servos complex sophisticated partner modern Radio Control systems Gear train normally has five gears quality look reinforced material shiny thickness ball bearings Input Reference Pulse Generator Feedback Potentiometer SERVO FUNCTION 15 MS 1020 MSMS An RC Radio Control servo very sophisticated electromechanical device stage has mate others perfectly cause deterioration final results can consider servo three separate entities motor gear train electronics ultimate job servo convert electrical energy battery physical energy motor last link chain its quality determines power output efficiency servo Let engineers worry about formulas involved just accept current consumed greater muscle power available servo arm common motor ferrite permanent magnet DC Direct Current ie battery current motor Its moving part steel armature wrapped turns wire rotating between pair magnets RC servos three- fivepole motors referring number windings used five-pole motor runs smoother full speed will develop slightly power however important remember servo motor seldom runs period time full speed armature heavy takes time pick up speed wants coast once power cut off coreless motor can thought being made inside-out armature actually coil wrapped wire steel center magnets fixed within armature spins around advantages lighter armature speeds up faster stops quicker coreless motor far precise respects therefore costs gear train required couple motor shaft output arm required speed gear ratio extremely high300-400 1 designed result powerful servo acts faster As things mechanical no freebies given motor input voltage can have either both gear train has job driving pot potentiometera variable resistor shaft rotates step servo output job provide feedback signal telling servo stop way does another quality costaffecting feature earlier some current cheapies pot shaft connected servo output works until heavy load placed output can place enough pressure pot shaft upset its function causing erratic servo action better way indirect servo drive requires another gear connected output thus pressure applied arm will transferred pot shaft Ball bearings ball-bearingsupported shaft should operate truer freer kind solid bushing servos used support output gear shaftsome bearing top better ones also base Its another reason costlier servos will result superior performance Now electronicsthe so-called amplifier much simple amplifier cheapest ones quite involved Regardless cost basically same thing process information generated transmitter inputs drive motor required direction degree follow inputs process called PWM Pulse Width Modulation no such thing PCM Pulse Code Modulation servo PCM system ultimate servo-driving command has changed PWM forget about PPM Pulse Position Modulation term incorrect regardless its common use know better non-PCM system operates PWM another story width Pulse Width control signal tells servo what frequency standard 10-20 mS millisecond /iooo second-long pulse centering 15 inS other words transmitter generating string such pulsesone channelthat processed directed proper servo receiver stick neutral servo neutral Moving stick increases decreases pulse length servo will operate appropriate direction Operating transmitter servo reverse reverses signal changes stick moved Within amplifier incoming signal first applied comparator might expect name compares its length internal 15 mS reference difference read fed pulse stretcher also does what its name implies Next comes some driver circuitry based whether pulse length now less 15 feeds current motor proper polarity make turn desired direction motor turns Whoa Remember gear-driven feedback pot Its function adjust output reference generator match incoming pulse match difference length canceled out motor commanded stop servo will stay until next stick movement process starts again proper direction Enjoy RELMILE S-L-G-O-W Idle PLUS. 457 S4FE studs Single Twin-cylinders Twin engines WO Interference Works Rxs Light Less 35 grams Ultra-simple installation E DiLl II mXLFJL1 o No messy adJustments Computer-accurate neutral o No Jitter U No Drift Neutral Sh4fis temperature changes U Fuelproof Vibration proof Encapsulated space-age epoxy WUKI SUI4jAJL 31185 Schoolcraft Livania Ml 48150 Website httpI/wwwelecfrodynamcOm 1-800-337-1638 Orders 1-734-422 5420 VISA Fax 1734-4225338 September 1999 67 line up yourtar long slow approach. Theres no tear tiameouts GlowLites onboardi doesnt Ret better this. EDR-106 P Snrnn 7niriir SEER tinan 1-2-3 Plug jeer serve late Pr Serve Reverser Plug Pr Serve Reverser late peer Ra Wew Peere done E xclusively Canopies Two sizes Small 3/16 47mm Large 1/4 64mm Canopy Trim Fourmost Canopy Trim flexible black vinyl strip preformed make perfect mounting trim canopies 4 Feet 122 meters per package Because the Canopy Trims unique shape flexibility will contour both flat round fuselages Canopy Trim secures canopy place well providing realistic black outline Canopy Trim may easily installed just razor blade CA adhesive small Product No 139 Large Product No 140 Price $3 95 FOURMOST PRODUCTS Look other great products Fourmost nearest hobby dealer direct orders include $4 50 Shipping 4040 24th Avenue Forest Grove OR 97116 Phone/Fax 503 357 2732 internet www tourmost com l rcooney@ntrnet Makes starting easier sater Keeps GLOWDRnRglow plug hotjusiwhev yourerrgine needs Connects hetween throttle servo receiver reversibie seiectable ts unit can drive two stow piogs turns 00 troosmiser ott t00% electronic made USA Compotihie AM FM PCM roSin systems Low power consumption comes hookup wire Less radio connector pownr net plug clip Sloe t 7 0 t 2 0 04 Weight 04. . Port No SA $3495 $3750 wconnector $4485 WIradio systems Low power consumption Less connector & piog cup CALL corepiete singie twioengiee andradio power connectors Size tb o 505 n 05 Weight t 2 no twiocpiinder systemsPart No ou $3495 $3780 radio connector Gives older DuAL-Ouwur SER voRs VERSUR ruAss ability reverse direction hems operation installations setups easier convenient Provides both normal reversed output use Y connector makes spilt elevator two-servo ailerons double-servo rudder installation super-eahy t 00% electronic no setup taoslust nennect torget Made USA works AM FM PCM radio systems Ultra-low power consumption Less radio connector Sloe t 0000 004 Weight 025 Part No 2U $2495 $2750 comptete Wiconflector Complete vyvtemv other producto avaitahte etanes coca Sooth Catt write fan detaith Gives standard radios ability . vtaiis ilaps spoilers aileronlrudder coupling busy setup installation Rugged micraprocessorbased design 100% electronic br high reliability Simply connect miver between eemos receiver Features two mioing modes individual semo reversing tour digerent mising rates teatures allow tailor miser needs ot model Will overdrine servos options selected simple switches Made USA designed tar AM FM PCM radio systems very low power consumption Less radio connectors Sloe t ha 00 004 Weight 025 PartNo OA $3055 $3085 compiete wlcoooectors numerous points performance can deteriorated Motor first poor motor poor servo Gear slop obvious including pot drive amplifier have deal voltage temperature variations both can affect its operation can read unwanted movement servo arm wheel Especially higher-power servos current-handling capacity drive circuitry critical Ratings Consumers given speed torque ratings servo makers can understand speed fractions second though some cases stated time 900 movement others 600 such instances reported time same different servos moving 90 faster Torque Reported ounce-inches ie its measure force generated end one-inch arm generally published ounce/inches ounces divided inches However should ounceinches ounces relative inches However reported higher torque rating work servo capable doing another two important often unrecognized facts First energy produced servo free comes battery Faster heavier airplanes use battery current Sloppy installations use battery current does friction anywhere control linkage stalled servo such mechanically bottoms often seen throttle nose wheel steering installations can fatal Second servo does produce rated torque time operates maximum torque possible What does produce determined load applied amount control surface deflection commanded scratches surface start toward better understanding what makes servos work flying serious airplanes save money wherever can servos dont need fastest powerful servo expensive controls since throttles smoke valves etc life-threatening can generally operated lessthan-optimum servos Use better servos primary flight controls Super Servos h la JR Microprocessor servos latest developments interchangeability much will have wait until next time odel Aviation ELAND MODEL & SUPPLY CO P0 Box 55962AA Indianapolis IN 46205-0962 4I LI~Phone 317 257-7878 Fax 317 257-7877 MODEL ENGINEERS SINCE 1919 Choose Over 1100 Plans Over 100 Aircraft Manufacturers Represented Five Aviation Eras Spanned Seven Scales Available 48-page Catalog- $500 $800 Foreign P 0 Box 3129 US CHRISTi TX 78463-3129 Add $550 S&H Genres torveson 0 Cuseonee Sconce Sbt St 4-0543 5endt TX Renidanto Honey M-F ttuobro Cnsveu FAX &Arvcv Hvinv l3btl Std5843 FREU odd 7575% isorosce booiL & Tucesicut Snurn pmetek@uwbeltnetCatalogsaiestao
Edition: Model Aviation - 1999/09
Page Numbers: 66, 67, 68
Pulse ComparatorStretcherDriverOutputM Ge THE MAIL initial columns has extensive Thanks support giving idea things interest mail has will answered personally consider general interest will answered pages MA Surprisingly enough majority questions have about batteries have past about servos Dick Lehmann Wasau WI condensed notes letter Please write column discussing servos work What differences between different models some much expensive others Maybe read wrong magazines have yet see good article servos Well Dick article servos coming up Cost little doubt exception items marketed bought show-off appeal quality reliability expensive can get TimexTM $10 Rolex[M $ 10000both tell time can buy Fuji camera $2995 NikoniM $2995both take pictures differences same applies servos costly servos assembled using better grade electronic components greater mechanical precision common-type ferrite motor will cost less $10 motor cureless servo will $30 plugs money-saver silver-coloredprobably tin-plated better-class servos gold-plated dont know exact difference cost latter expensive printed circuit board cheapie will thin phenolic subject bowing little shock read crash resistance better boards fiberglass-reinforced epoxy usually twice thick metal gears expensivegenerally five six times much probably get picture Now little bit theory digestible level Servos commanded length Block diagram servo amplifiers inner workings Most circuitry contained control pulse varies between single IC Integrated Circuitminimal external componentsio 20 inS centering 15 inS 66 Model Aviation oy Marez Generally regarded necessary evil servos complex sophisticated partner modern Radio Control systems Gear train normally has five gears quality look reinforced material shiny thickness ball bearings Input Reference Pulse Generator Feedback Potentiometer SERVO FUNCTION 15 MS 1020 MSMS An RC Radio Control servo very sophisticated electromechanical device stage has mate others perfectly cause deterioration final results can consider servo three separate entities motor gear train electronics ultimate job servo convert electrical energy battery physical energy motor last link chain its quality determines power output efficiency servo Let engineers worry about formulas involved just accept current consumed greater muscle power available servo arm common motor ferrite permanent magnet DC Direct Current ie battery current motor Its moving part steel armature wrapped turns wire rotating between pair magnets RC servos three- fivepole motors referring number windings used five-pole motor runs smoother full speed will develop slightly power however important remember servo motor seldom runs period time full speed armature heavy takes time pick up speed wants coast once power cut off coreless motor can thought being made inside-out armature actually coil wrapped wire steel center magnets fixed within armature spins around advantages lighter armature speeds up faster stops quicker coreless motor far precise respects therefore costs gear train required couple motor shaft output arm required speed gear ratio extremely high300-400 1 designed result powerful servo acts faster As things mechanical no freebies given motor input voltage can have either both gear train has job driving pot potentiometera variable resistor shaft rotates step servo output job provide feedback signal telling servo stop way does another quality costaffecting feature earlier some current cheapies pot shaft connected servo output works until heavy load placed output can place enough pressure pot shaft upset its function causing erratic servo action better way indirect servo drive requires another gear connected output thus pressure applied arm will transferred pot shaft Ball bearings ball-bearingsupported shaft should operate truer freer kind solid bushing servos used support output gear shaftsome bearing top better ones also base Its another reason costlier servos will result superior performance Now electronicsthe so-called amplifier much simple amplifier cheapest ones quite involved Regardless cost basically same thing process information generated transmitter inputs drive motor required direction degree follow inputs process called PWM Pulse Width Modulation no such thing PCM Pulse Code Modulation servo PCM system ultimate servo-driving command has changed PWM forget about PPM Pulse Position Modulation term incorrect regardless its common use know better non-PCM system operates PWM another story width Pulse Width control signal tells servo what frequency standard 10-20 mS millisecond /iooo second-long pulse centering 15 inS other words transmitter generating string such pulsesone channelthat processed directed proper servo receiver stick neutral servo neutral Moving stick increases decreases pulse length servo will operate appropriate direction Operating transmitter servo reverse reverses signal changes stick moved Within amplifier incoming signal first applied comparator might expect name compares its length internal 15 mS reference difference read fed pulse stretcher also does what its name implies Next comes some driver circuitry based whether pulse length now less 15 feeds current motor proper polarity make turn desired direction motor turns Whoa Remember gear-driven feedback pot Its function adjust output reference generator match incoming pulse match difference length canceled out motor commanded stop servo will stay until next stick movement process starts again proper direction Enjoy RELMILE S-L-G-O-W Idle PLUS. 457 S4FE studs Single Twin-cylinders Twin engines WO Interference Works Rxs Light Less 35 grams Ultra-simple installation E DiLl II mXLFJL1 o No messy adJustments Computer-accurate neutral o No Jitter U No Drift Neutral Sh4fis temperature changes U Fuelproof Vibration proof Encapsulated space-age epoxy WUKI SUI4jAJL 31185 Schoolcraft Livania Ml 48150 Website httpI/wwwelecfrodynamcOm 1-800-337-1638 Orders 1-734-422 5420 VISA Fax 1734-4225338 September 1999 67 line up yourtar long slow approach. Theres no tear tiameouts GlowLites onboardi doesnt Ret better this. EDR-106 P Snrnn 7niriir SEER tinan 1-2-3 Plug jeer serve late Pr Serve Reverser Plug Pr Serve Reverser late peer Ra Wew Peere done E xclusively Canopies Two sizes Small 3/16 47mm Large 1/4 64mm Canopy Trim Fourmost Canopy Trim flexible black vinyl strip preformed make perfect mounting trim canopies 4 Feet 122 meters per package Because the Canopy Trims unique shape flexibility will contour both flat round fuselages Canopy Trim secures canopy place well providing realistic black outline Canopy Trim may easily installed just razor blade CA adhesive small Product No 139 Large Product No 140 Price $3 95 FOURMOST PRODUCTS Look other great products Fourmost nearest hobby dealer direct orders include $4 50 Shipping 4040 24th Avenue Forest Grove OR 97116 Phone/Fax 503 357 2732 internet www tourmost com l rcooney@ntrnet Makes starting easier sater Keeps GLOWDRnRglow plug hotjusiwhev yourerrgine needs Connects hetween throttle servo receiver reversibie seiectable ts unit can drive two stow piogs turns 00 troosmiser ott t00% electronic made USA Compotihie AM FM PCM roSin systems Low power consumption comes hookup wire Less radio connector pownr net plug clip Sloe t 7 0 t 2 0 04 Weight 04. . Port No SA $3495 $3750 wconnector $4485 WIradio systems Low power consumption Less connector & piog cup CALL corepiete singie twioengiee andradio power connectors Size tb o 505 n 05 Weight t 2 no twiocpiinder systemsPart No ou $3495 $3780 radio connector Gives older DuAL-Ouwur SER voRs VERSUR ruAss ability reverse direction hems operation installations setups easier convenient Provides both normal reversed output use Y connector makes spilt elevator two-servo ailerons double-servo rudder installation super-eahy t 00% electronic no setup taoslust nennect torget Made USA works AM FM PCM radio systems Ultra-low power consumption Less radio connector Sloe t 0000 004 Weight 025 Part No 2U $2495 $2750 comptete Wiconflector Complete vyvtemv other producto avaitahte etanes coca Sooth Catt write fan detaith Gives standard radios ability . vtaiis ilaps spoilers aileronlrudder coupling busy setup installation Rugged micraprocessorbased design 100% electronic br high reliability Simply connect miver between eemos receiver Features two mioing modes individual semo reversing tour digerent mising rates teatures allow tailor miser needs ot model Will overdrine servos options selected simple switches Made USA designed tar AM FM PCM radio systems very low power consumption Less radio connectors Sloe t ha 00 004 Weight 025 PartNo OA $3055 $3085 compiete wlcoooectors numerous points performance can deteriorated Motor first poor motor poor servo Gear slop obvious including pot drive amplifier have deal voltage temperature variations both can affect its operation can read unwanted movement servo arm wheel Especially higher-power servos current-handling capacity drive circuitry critical Ratings Consumers given speed torque ratings servo makers can understand speed fractions second though some cases stated time 900 movement others 600 such instances reported time same different servos moving 90 faster Torque Reported ounce-inches ie its measure force generated end one-inch arm generally published ounce/inches ounces divided inches However should ounceinches ounces relative inches However reported higher torque rating work servo capable doing another two important often unrecognized facts First energy produced servo free comes battery Faster heavier airplanes use battery current Sloppy installations use battery current does friction anywhere control linkage stalled servo such mechanically bottoms often seen throttle nose wheel steering installations can fatal Second servo does produce rated torque time operates maximum torque possible What does produce determined load applied amount control surface deflection commanded scratches surface start toward better understanding what makes servos work flying serious airplanes save money wherever can servos dont need fastest powerful servo expensive controls since throttles smoke valves etc life-threatening can generally operated lessthan-optimum servos Use better servos primary flight controls Super Servos h la JR Microprocessor servos latest developments interchangeability much will have wait until next time odel Aviation ELAND MODEL & SUPPLY CO P0 Box 55962AA Indianapolis IN 46205-0962 4I LI~Phone 317 257-7878 Fax 317 257-7877 MODEL ENGINEERS SINCE 1919 Choose Over 1100 Plans Over 100 Aircraft Manufacturers Represented Five Aviation Eras Spanned Seven Scales Available 48-page Catalog- $500 $800 Foreign P 0 Box 3129 US CHRISTi TX 78463-3129 Add $550 S&H Genres torveson 0 Cuseonee Sconce Sbt St 4-0543 5endt TX Renidanto Honey M-F ttuobro Cnsveu FAX &Arvcv Hvinv l3btl Std5843 FREU odd 7575% isorosce booiL & Tucesicut Snurn pmetek@uwbeltnetCatalogsaiestao