THE FOR SS4ESREE SERVO U Richard Carignan 900 -inch Travel {707 inches Ounces Available Force 500 inches-i FIGURE 1 Typical standard servo 900 travel 42 ounce-inches torque one-inch pushrod travel 7 inch arm required 594 ounces force can obtained neutral $ 1800 L7 500 inches 594 Ounces Force inch Travel 84 Ounces _- Available Force 7W FIGURE 2 . Force limited strength linkage servo mechanics locked condition Standard servo 1800 rotation Shorter arm gives higher output force same one-inch travel TODAYS RADIO CONTROL servos have reached remarkable degree function versatility reliability low cost available variety sizes output torque levels satisfy requirements just about RC application Except special fairly expensive servos used sailboat applications devices have rotaly outputs turn 450 covering 900 arc article describes modification increases servo arm rotation 450 900 1800 total actuating force can obtained servos expense reduced transit time modification can either change servo electronics interface device between receiver servo applications reduced transit time concern l80 servo can perform functions using smaller servo size thereby saving weight cost An additional advantage locking action very high output force servo endpoints method servo modification achieve 1800 described Typical servo operation 900 output arm rotation shown Figure 1 values indicated standard servo 42 ounceinches output torque application requires inch total pushrod actuation servo arm length 707 inch required case available force neutral 42 ounce-inches divided 707 inchesa force 594 ounces servo ann rotates away neutral available force increases 450 available force 42/5 unces desirable because force required deflect control surface airstream also increases movement neutral Applications true would flaps servo-actuated retractable landing gear servo neutral position flaps retract landing gear present loads servo reason cases larger higher-torque servos needed applications Figure 2 shows same servo used Figure 1 modification obtain 1800 output 5 inch servo arm length pushrod travel still inch force neutral increased about 40 percent available force neutral now 84 ounces 50 Model Aviation neutral available force increases breaking point servo linkages endpoint locking additional advantage 1800 servo locked condition no additional servo current required maintain actuating force battery drain reduced compared servo setup requires holding current maintain its position flap application Disadvantages 1800 servo rotation Transit time doubled although problem flaps retracts Requires dedicated internal servo modification interface device Pushrod end-to-end travel adjustable changing servo arm length Change feedback voltage method have used successfully several applications first use flaps 1/5-scale Cessna Bird Dog done adding resistors servo feedback pot Schematically Figure 3 shows required modification increase servo travel 90 1800 Total feedback pot resistance across end terminals typically 5000 ohms Addition two resistors end pot reduces output voltage change per degree shaft rotation half Servo modification requires some mechanical simple soldering skills Servos smaller standard size easily modified some have gear travel limits allow 1800 travel following description covers modification standard-size Futaba S3003 servo Prepare clean work area white sheet paper bench works well Remove four screws bottom servo cover will reveal circuit board input lead connections Before removing upper case hold down servo output shaft finger keep internal gears place case lifted carefully may find intermediate gears will come loose small gear pin comes off upper case case replace pin gears may have displaced Connect servo receiver channel center neutral position such elevator set trim center have transmitter has adjustable neutral set neutral standard position 15 ins Switch receiver transmitter Note output gear cog position used Graphic Design Jill Ann Gavanaugh Resistor Added Feedback Pot Regulated Voltage R2 Feedback Pot Resistance 5K ohms 4 Ri Battery Minus FIGURE 3 Modification 1800 rotation requires addition resistors feedback pot shown Resistor values Ri plus R2 total pot resistance See text Ri R2 resistance values Pushrods Z-bends top servo armsrequired 1800 rotation Threaded devises pushrod ends adjustment Voltage Servo Board Slider Moves Servo Arm Pushrods have slight bends servo end applications using servo drive two flaps retracts November 1998 51 Make smaller value resistor offset minus Use larger value offset plus See table below FIGURE 5 RESISTOR TABLE Neutral Offset Angle Degrees o toll 11 26 26 41 Resistor Values K Ohms 27 24 33 18 39 12 Cut outer leads feedback pot leaving /32 inch Trim leads 1/4 watt resistors solder shown sure use high low values proper positions indicated mechanical stop see Figure 4 Switch off receiver transmitter Determine approximate number degrees center output gear cog located An easy way to count number gear teeth away center cog located servos have checked gear has 41 teeth 880 per tooth Record angle note side offset occurs indicated Figure 4 information will used select end resistors location Remove gears noting positions servo has screws holding motor place remove will notice two slots servo case both sides pot shaft keyed output gear provide access two catches hold pot position Since pot connected circuit board short solid leads servo must released catches before board can lifted out have success releasing catches using small jewelers screwdriver two small pieces metal chisel point pressed slot between pot body catches works well small wedges fit between pot body catches pushing catches away pot body Putting slight pressure pot shaft during operation helps release catches pot releases complete servo board motor pot can removed case may need gently pry up circuit board free case use excessive force Referring Figure 5 identify pots two end terminals will left right viewed servo end Cut out section leads leaving about 3/32-inch lengths board pot servos feedback pot nominal 5K ohms resistor values shown Figure 5 table will have scaled proportion pot resistance relative 5K resistance Select resistor values table Figure 5 Except 33K values stocked Radio Shack can obtained special order cannot find resistors need send SASE author will sent no charge supply lasts Trim two selected -watt resistor leads fit between circuit board pot terminal shown Figure 5 Referring Figure 5 select required resistor solder between circuit board pot Trim second lead between pot board solder other resistor place Check soldering job bridges small balls solder may have formed thoroughly clean unit Set pot shaft its midrange position Carefully return unit its case push circuit board make pot body snap catches pot shaft just starts protrude through case pull pot position engage catches using long-nose pliers flats pot shaft Place output gear over pot shaft check its rotation ease motion 52 Model Aviation Minus Output Gear Gear FIGURE 4 Before removing servo cover gears set servo neutral cover removed measure neutral offset angle note direction 1- shown will used select resistor values figure 5 0. i7KO 0 0 0 000 00 PC Board Motor Pot gear cog should positioned pointing case end Figure 4 Reinstall remaining gears pins case covers Connect servo receiver before turn transmitter servo should respond control stick movement controlling channel neutral temporarily attach servo output arm can observe angular output-arm rotation Move control stick see getting 1800 rotation servo shaft moves 1800 hitting stops finished could servo drive gear hitting its stop need adjust transmitter travel Listen carefully servo hitting internal stop will hear servo hum trying go beyond stop servo will also drawing high stall current condition Mechanical setup 1800 servo requires use Z-bend servo end pushrod shown figure 6 enters servo arm top side threaded clevis should used other pushrod end provide adjustment application using servo drive two flaps two retracts Z-bend ends push rods must have slight bend shown figure 7 50 full 180 degree rotation can obtained Use Y connector using two servos same function such left right flaps some cases two servos used single application may necessary reverse rotation servo obtain desired actuation both devices can achieved servo modification purchase reversed servo interface circuit available several sources advertise model publications can make own reverser See MA May 1997 article Brent Dane An interface device between receiver servo increases signal pulse length rate-of-change another method get 80 servo rotation Since seen such unit advertised several companies sell electronic devices searched Internet US Patent Office site relative patents subject search turned up patent February 1997 exactly type device based microcontroller technology inventor Walter S Polan manufactures unit called Servo Genie servo extender also has servo-reversing option developed device part work movie special-effects industry company called Electrofex Glendale CA unit available Robbins Hobby also Glendale CA r Carignan 39 Glen Road Wilmington MA 01887 rogercar@gisnet RED M FUELSRED NIAiXI tulates Kirk excellent FHS Supply488performance 1st Place FHS803 22Z13fi World Chamnlo Winners AMA Air NationalsUsing spaceage lubrication tecnology op 1997 112A CombatFHS Oil -Bob Mearsquality components developed refined over 1996 FAI Pattern Kirk Gray28 years experience RED MAX fuels 1996 Sportsman Randy Wolfespecially engineered Maximum Performance MAC Scale Aerobatic NationalsPower Protection RED MAX known 1997 Sportsman Michael Kupersold internationally best fuel can IRCHA Helicooter Internationalsuse model engine Fuel model types available planes helicopters boats cars -- racing pattern just fun 1997 10cc TopSpeed Bruce Bennett 1997 10cc TimeToClib Bruce Bennett NAMBA Boat Nationals 1996 A-OPC 35cc Mod Tun Joe Monohan 1996 B-OPC 75cc Mod Tun Don Hirami 1996 C-OPC 11cc Mod Tun Mike McKabney 1996 C-OPC 11cc Stock Tun Joe Monohan Other contests nationwide Numerous awards year FHS Supply lncPO Box 9CloverSC 29710-0009 Sales800 742-8484Voice 803 222-7488 lnternetFHSoil@aolcom Fax803 222-7285 httpllmembersaolcomlFHSoillRedMaxhtml Engine types 2 4 cycle Glow Diesel Nitro Power blends 0% 75% 5% Oil blends RED MAX Synthetic Syn-Cas Blend 0Customer special blends available0 Minimum gal Standard 4-gal 20-qt Cases Shipping UPS door 12 gal motorfreight commercial address Price breaks 412 2060 124 gal Special discount prepaid club orders RED MAX Shirts Hats & Stickers available ge AA CH Electronics headquarters hqht weioht weed trimmer conversions Pdces inclado switch harneno battery 5650 postage & handling All CH $11995 Mcculloch 28/32 Homelite 25/30 Ryobi 26 4031 2c ignitions $18995 Honda 0031 are iuiiy Insc,iteotnmpmnhobmisaoH0Ioaoown,,nmaserviceable EI,micrmmg OpFoo Hi PerOrmac carts motor macro muffle Lutortcraeroacyccresrrcionoowsaoro $9995 HD replacement ignition Bosch plug captor Sacho based angines $14495 HO replacement ignition syocm ttparfr Bosch cap $12495 Zenoab 0-45 G62 Zdd5 Ouick Mount 5yncro sparlr Ignition Hood stags slower/smoother idle bettor top end Reqoirea no machining Mace mere ianiiiwn carts anseries sasilaisla Sarad 53151, nimw list narcarelama November 1998 55 Engines left right Hands GX31 Ryabi 31 llacir 32 ife 25 D & J ELECTRONICS Marigold St NW Hartvllle OH 44632 1236330-877-1445 Ii Service & Repairs Most Radio Control Systems Utilizing Calibrated Test Equipment & Spectrum Analyzers Endors.d AMAi RCMA Sticker Station #105 Futaba Airtronics JR Ace HiTec Tower Cirrus World Engines & WE USE GENUINE FACTORY REPLACEMENT PARTS Complete 1991 Narrow Banding & Upgrades RCD / HITEC R/C DEALER FCC Licensed Speed Control Repairs Quality Service Fast Turn Around Shipping & Insurance Extra UPS Mail Visit hont pagt http//wwwdttIelectronics corn Email davld@dnleIectronicscom jayne@dnjelectronics AMA #256123ARRLWB8YS
Edition: Model Aviation - 1998/11
Page Numbers: 50, 51, 52, 55
Edition: Model Aviation - 1998/11
Page Numbers: 50, 51, 52, 55
THE FOR SS4ESREE SERVO U Richard Carignan 900 -inch Travel {707 inches Ounces Available Force 500 inches-i FIGURE 1 Typical standard servo 900 travel 42 ounce-inches torque one-inch pushrod travel 7 inch arm required 594 ounces force can obtained neutral $ 1800 L7 500 inches 594 Ounces Force inch Travel 84 Ounces _- Available Force 7W FIGURE 2 . Force limited strength linkage servo mechanics locked condition Standard servo 1800 rotation Shorter arm gives higher output force same one-inch travel TODAYS RADIO CONTROL servos have reached remarkable degree function versatility reliability low cost available variety sizes output torque levels satisfy requirements just about RC application Except special fairly expensive servos used sailboat applications devices have rotaly outputs turn 450 covering 900 arc article describes modification increases servo arm rotation 450 900 1800 total actuating force can obtained servos expense reduced transit time modification can either change servo electronics interface device between receiver servo applications reduced transit time concern l80 servo can perform functions using smaller servo size thereby saving weight cost An additional advantage locking action very high output force servo endpoints method servo modification achieve 1800 described Typical servo operation 900 output arm rotation shown Figure 1 values indicated standard servo 42 ounceinches output torque application requires inch total pushrod actuation servo arm length 707 inch required case available force neutral 42 ounce-inches divided 707 inchesa force 594 ounces servo ann rotates away neutral available force increases 450 available force 42/5 unces desirable because force required deflect control surface airstream also increases movement neutral Applications true would flaps servo-actuated retractable landing gear servo neutral position flaps retract landing gear present loads servo reason cases larger higher-torque servos needed applications Figure 2 shows same servo used Figure 1 modification obtain 1800 output 5 inch servo arm length pushrod travel still inch force neutral increased about 40 percent available force neutral now 84 ounces 50 Model Aviation neutral available force increases breaking point servo linkages endpoint locking additional advantage 1800 servo locked condition no additional servo current required maintain actuating force battery drain reduced compared servo setup requires holding current maintain its position flap application Disadvantages 1800 servo rotation Transit time doubled although problem flaps retracts Requires dedicated internal servo modification interface device Pushrod end-to-end travel adjustable changing servo arm length Change feedback voltage method have used successfully several applications first use flaps 1/5-scale Cessna Bird Dog done adding resistors servo feedback pot Schematically Figure 3 shows required modification increase servo travel 90 1800 Total feedback pot resistance across end terminals typically 5000 ohms Addition two resistors end pot reduces output voltage change per degree shaft rotation half Servo modification requires some mechanical simple soldering skills Servos smaller standard size easily modified some have gear travel limits allow 1800 travel following description covers modification standard-size Futaba S3003 servo Prepare clean work area white sheet paper bench works well Remove four screws bottom servo cover will reveal circuit board input lead connections Before removing upper case hold down servo output shaft finger keep internal gears place case lifted carefully may find intermediate gears will come loose small gear pin comes off upper case case replace pin gears may have displaced Connect servo receiver channel center neutral position such elevator set trim center have transmitter has adjustable neutral set neutral standard position 15 ins Switch receiver transmitter Note output gear cog position used Graphic Design Jill Ann Gavanaugh Resistor Added Feedback Pot Regulated Voltage R2 Feedback Pot Resistance 5K ohms 4 Ri Battery Minus FIGURE 3 Modification 1800 rotation requires addition resistors feedback pot shown Resistor values Ri plus R2 total pot resistance See text Ri R2 resistance values Pushrods Z-bends top servo armsrequired 1800 rotation Threaded devises pushrod ends adjustment Voltage Servo Board Slider Moves Servo Arm Pushrods have slight bends servo end applications using servo drive two flaps retracts November 1998 51 Make smaller value resistor offset minus Use larger value offset plus See table below FIGURE 5 RESISTOR TABLE Neutral Offset Angle Degrees o toll 11 26 26 41 Resistor Values K Ohms 27 24 33 18 39 12 Cut outer leads feedback pot leaving /32 inch Trim leads 1/4 watt resistors solder shown sure use high low values proper positions indicated mechanical stop see Figure 4 Switch off receiver transmitter Determine approximate number degrees center output gear cog located An easy way to count number gear teeth away center cog located servos have checked gear has 41 teeth 880 per tooth Record angle note side offset occurs indicated Figure 4 information will used select end resistors location Remove gears noting positions servo has screws holding motor place remove will notice two slots servo case both sides pot shaft keyed output gear provide access two catches hold pot position Since pot connected circuit board short solid leads servo must released catches before board can lifted out have success releasing catches using small jewelers screwdriver two small pieces metal chisel point pressed slot between pot body catches works well small wedges fit between pot body catches pushing catches away pot body Putting slight pressure pot shaft during operation helps release catches pot releases complete servo board motor pot can removed case may need gently pry up circuit board free case use excessive force Referring Figure 5 identify pots two end terminals will left right viewed servo end Cut out section leads leaving about 3/32-inch lengths board pot servos feedback pot nominal 5K ohms resistor values shown Figure 5 table will have scaled proportion pot resistance relative 5K resistance Select resistor values table Figure 5 Except 33K values stocked Radio Shack can obtained special order cannot find resistors need send SASE author will sent no charge supply lasts Trim two selected -watt resistor leads fit between circuit board pot terminal shown Figure 5 Referring Figure 5 select required resistor solder between circuit board pot Trim second lead between pot board solder other resistor place Check soldering job bridges small balls solder may have formed thoroughly clean unit Set pot shaft its midrange position Carefully return unit its case push circuit board make pot body snap catches pot shaft just starts protrude through case pull pot position engage catches using long-nose pliers flats pot shaft Place output gear over pot shaft check its rotation ease motion 52 Model Aviation Minus Output Gear Gear FIGURE 4 Before removing servo cover gears set servo neutral cover removed measure neutral offset angle note direction 1- shown will used select resistor values figure 5 0. i7KO 0 0 0 000 00 PC Board Motor Pot gear cog should positioned pointing case end Figure 4 Reinstall remaining gears pins case covers Connect servo receiver before turn transmitter servo should respond control stick movement controlling channel neutral temporarily attach servo output arm can observe angular output-arm rotation Move control stick see getting 1800 rotation servo shaft moves 1800 hitting stops finished could servo drive gear hitting its stop need adjust transmitter travel Listen carefully servo hitting internal stop will hear servo hum trying go beyond stop servo will also drawing high stall current condition Mechanical setup 1800 servo requires use Z-bend servo end pushrod shown figure 6 enters servo arm top side threaded clevis should used other pushrod end provide adjustment application using servo drive two flaps two retracts Z-bend ends push rods must have slight bend shown figure 7 50 full 180 degree rotation can obtained Use Y connector using two servos same function such left right flaps some cases two servos used single application may necessary reverse rotation servo obtain desired actuation both devices can achieved servo modification purchase reversed servo interface circuit available several sources advertise model publications can make own reverser See MA May 1997 article Brent Dane An interface device between receiver servo increases signal pulse length rate-of-change another method get 80 servo rotation Since seen such unit advertised several companies sell electronic devices searched Internet US Patent Office site relative patents subject search turned up patent February 1997 exactly type device based microcontroller technology inventor Walter S Polan manufactures unit called Servo Genie servo extender also has servo-reversing option developed device part work movie special-effects industry company called Electrofex Glendale CA unit available Robbins Hobby also Glendale CA r Carignan 39 Glen Road Wilmington MA 01887 rogercar@gisnet RED M FUELSRED NIAiXI tulates Kirk excellent FHS Supply488performance 1st Place FHS803 22Z13fi World Chamnlo Winners AMA Air NationalsUsing spaceage lubrication tecnology op 1997 112A CombatFHS Oil -Bob Mearsquality components developed refined over 1996 FAI Pattern Kirk Gray28 years experience RED MAX fuels 1996 Sportsman Randy Wolfespecially engineered Maximum Performance MAC Scale Aerobatic NationalsPower Protection RED MAX known 1997 Sportsman Michael Kupersold internationally best fuel can IRCHA Helicooter Internationalsuse model engine Fuel model types available planes helicopters boats cars -- racing pattern just fun 1997 10cc TopSpeed Bruce Bennett 1997 10cc TimeToClib Bruce Bennett NAMBA Boat Nationals 1996 A-OPC 35cc Mod Tun Joe Monohan 1996 B-OPC 75cc Mod Tun Don Hirami 1996 C-OPC 11cc Mod Tun Mike McKabney 1996 C-OPC 11cc Stock Tun Joe Monohan Other contests nationwide Numerous awards year FHS Supply lncPO Box 9CloverSC 29710-0009 Sales800 742-8484Voice 803 222-7488 lnternetFHSoil@aolcom Fax803 222-7285 httpllmembersaolcomlFHSoillRedMaxhtml Engine types 2 4 cycle Glow Diesel Nitro Power blends 0% 75% 5% Oil blends RED MAX Synthetic Syn-Cas Blend 0Customer special blends available0 Minimum gal Standard 4-gal 20-qt Cases Shipping UPS door 12 gal motorfreight commercial address Price breaks 412 2060 124 gal Special discount prepaid club orders RED MAX Shirts Hats & Stickers available ge AA CH Electronics headquarters hqht weioht weed trimmer conversions Pdces inclado switch harneno battery 5650 postage & handling All CH $11995 Mcculloch 28/32 Homelite 25/30 Ryobi 26 4031 2c ignitions $18995 Honda 0031 are iuiiy Insc,iteotnmpmnhobmisaoH0Ioaoown,,nmaserviceable EI,micrmmg OpFoo Hi PerOrmac carts motor macro muffle Lutortcraeroacyccresrrcionoowsaoro $9995 HD replacement ignition Bosch plug captor Sacho based angines $14495 HO replacement ignition syocm ttparfr Bosch cap $12495 Zenoab 0-45 G62 Zdd5 Ouick Mount 5yncro sparlr Ignition Hood stags slower/smoother idle bettor top end Reqoirea no machining Mace mere ianiiiwn carts anseries sasilaisla Sarad 53151, nimw list narcarelama November 1998 55 Engines left right Hands GX31 Ryabi 31 llacir 32 ife 25 D & J ELECTRONICS Marigold St NW Hartvllle OH 44632 1236330-877-1445 Ii Service & Repairs Most Radio Control Systems Utilizing Calibrated Test Equipment & Spectrum Analyzers Endors.d AMAi RCMA Sticker Station #105 Futaba Airtronics JR Ace HiTec Tower Cirrus World Engines & WE USE GENUINE FACTORY REPLACEMENT PARTS Complete 1991 Narrow Banding & Upgrades RCD / HITEC R/C DEALER FCC Licensed Speed Control Repairs Quality Service Fast Turn Around Shipping & Insurance Extra UPS Mail Visit hont pagt http//wwwdttIelectronics corn Email davld@dnleIectronicscom jayne@dnjelectronics AMA #256123ARRLWB8YS
Edition: Model Aviation - 1998/11
Page Numbers: 50, 51, 52, 55
THE FOR SS4ESREE SERVO U Richard Carignan 900 -inch Travel {707 inches Ounces Available Force 500 inches-i FIGURE 1 Typical standard servo 900 travel 42 ounce-inches torque one-inch pushrod travel 7 inch arm required 594 ounces force can obtained neutral $ 1800 L7 500 inches 594 Ounces Force inch Travel 84 Ounces _- Available Force 7W FIGURE 2 . Force limited strength linkage servo mechanics locked condition Standard servo 1800 rotation Shorter arm gives higher output force same one-inch travel TODAYS RADIO CONTROL servos have reached remarkable degree function versatility reliability low cost available variety sizes output torque levels satisfy requirements just about RC application Except special fairly expensive servos used sailboat applications devices have rotaly outputs turn 450 covering 900 arc article describes modification increases servo arm rotation 450 900 1800 total actuating force can obtained servos expense reduced transit time modification can either change servo electronics interface device between receiver servo applications reduced transit time concern l80 servo can perform functions using smaller servo size thereby saving weight cost An additional advantage locking action very high output force servo endpoints method servo modification achieve 1800 described Typical servo operation 900 output arm rotation shown Figure 1 values indicated standard servo 42 ounceinches output torque application requires inch total pushrod actuation servo arm length 707 inch required case available force neutral 42 ounce-inches divided 707 inchesa force 594 ounces servo ann rotates away neutral available force increases 450 available force 42/5 unces desirable because force required deflect control surface airstream also increases movement neutral Applications true would flaps servo-actuated retractable landing gear servo neutral position flaps retract landing gear present loads servo reason cases larger higher-torque servos needed applications Figure 2 shows same servo used Figure 1 modification obtain 1800 output 5 inch servo arm length pushrod travel still inch force neutral increased about 40 percent available force neutral now 84 ounces 50 Model Aviation neutral available force increases breaking point servo linkages endpoint locking additional advantage 1800 servo locked condition no additional servo current required maintain actuating force battery drain reduced compared servo setup requires holding current maintain its position flap application Disadvantages 1800 servo rotation Transit time doubled although problem flaps retracts Requires dedicated internal servo modification interface device Pushrod end-to-end travel adjustable changing servo arm length Change feedback voltage method have used successfully several applications first use flaps 1/5-scale Cessna Bird Dog done adding resistors servo feedback pot Schematically Figure 3 shows required modification increase servo travel 90 1800 Total feedback pot resistance across end terminals typically 5000 ohms Addition two resistors end pot reduces output voltage change per degree shaft rotation half Servo modification requires some mechanical simple soldering skills Servos smaller standard size easily modified some have gear travel limits allow 1800 travel following description covers modification standard-size Futaba S3003 servo Prepare clean work area white sheet paper bench works well Remove four screws bottom servo cover will reveal circuit board input lead connections Before removing upper case hold down servo output shaft finger keep internal gears place case lifted carefully may find intermediate gears will come loose small gear pin comes off upper case case replace pin gears may have displaced Connect servo receiver channel center neutral position such elevator set trim center have transmitter has adjustable neutral set neutral standard position 15 ins Switch receiver transmitter Note output gear cog position used Graphic Design Jill Ann Gavanaugh Resistor Added Feedback Pot Regulated Voltage R2 Feedback Pot Resistance 5K ohms 4 Ri Battery Minus FIGURE 3 Modification 1800 rotation requires addition resistors feedback pot shown Resistor values Ri plus R2 total pot resistance See text Ri R2 resistance values Pushrods Z-bends top servo armsrequired 1800 rotation Threaded devises pushrod ends adjustment Voltage Servo Board Slider Moves Servo Arm Pushrods have slight bends servo end applications using servo drive two flaps retracts November 1998 51 Make smaller value resistor offset minus Use larger value offset plus See table below FIGURE 5 RESISTOR TABLE Neutral Offset Angle Degrees o toll 11 26 26 41 Resistor Values K Ohms 27 24 33 18 39 12 Cut outer leads feedback pot leaving /32 inch Trim leads 1/4 watt resistors solder shown sure use high low values proper positions indicated mechanical stop see Figure 4 Switch off receiver transmitter Determine approximate number degrees center output gear cog located An easy way to count number gear teeth away center cog located servos have checked gear has 41 teeth 880 per tooth Record angle note side offset occurs indicated Figure 4 information will used select end resistors location Remove gears noting positions servo has screws holding motor place remove will notice two slots servo case both sides pot shaft keyed output gear provide access two catches hold pot position Since pot connected circuit board short solid leads servo must released catches before board can lifted out have success releasing catches using small jewelers screwdriver two small pieces metal chisel point pressed slot between pot body catches works well small wedges fit between pot body catches pushing catches away pot body Putting slight pressure pot shaft during operation helps release catches pot releases complete servo board motor pot can removed case may need gently pry up circuit board free case use excessive force Referring Figure 5 identify pots two end terminals will left right viewed servo end Cut out section leads leaving about 3/32-inch lengths board pot servos feedback pot nominal 5K ohms resistor values shown Figure 5 table will have scaled proportion pot resistance relative 5K resistance Select resistor values table Figure 5 Except 33K values stocked Radio Shack can obtained special order cannot find resistors need send SASE author will sent no charge supply lasts Trim two selected -watt resistor leads fit between circuit board pot terminal shown Figure 5 Referring Figure 5 select required resistor solder between circuit board pot Trim second lead between pot board solder other resistor place Check soldering job bridges small balls solder may have formed thoroughly clean unit Set pot shaft its midrange position Carefully return unit its case push circuit board make pot body snap catches pot shaft just starts protrude through case pull pot position engage catches using long-nose pliers flats pot shaft Place output gear over pot shaft check its rotation ease motion 52 Model Aviation Minus Output Gear Gear FIGURE 4 Before removing servo cover gears set servo neutral cover removed measure neutral offset angle note direction 1- shown will used select resistor values figure 5 0. i7KO 0 0 0 000 00 PC Board Motor Pot gear cog should positioned pointing case end Figure 4 Reinstall remaining gears pins case covers Connect servo receiver before turn transmitter servo should respond control stick movement controlling channel neutral temporarily attach servo output arm can observe angular output-arm rotation Move control stick see getting 1800 rotation servo shaft moves 1800 hitting stops finished could servo drive gear hitting its stop need adjust transmitter travel Listen carefully servo hitting internal stop will hear servo hum trying go beyond stop servo will also drawing high stall current condition Mechanical setup 1800 servo requires use Z-bend servo end pushrod shown figure 6 enters servo arm top side threaded clevis should used other pushrod end provide adjustment application using servo drive two flaps two retracts Z-bend ends push rods must have slight bend shown figure 7 50 full 180 degree rotation can obtained Use Y connector using two servos same function such left right flaps some cases two servos used single application may necessary reverse rotation servo obtain desired actuation both devices can achieved servo modification purchase reversed servo interface circuit available several sources advertise model publications can make own reverser See MA May 1997 article Brent Dane An interface device between receiver servo increases signal pulse length rate-of-change another method get 80 servo rotation Since seen such unit advertised several companies sell electronic devices searched Internet US Patent Office site relative patents subject search turned up patent February 1997 exactly type device based microcontroller technology inventor Walter S Polan manufactures unit called Servo Genie servo extender also has servo-reversing option developed device part work movie special-effects industry company called Electrofex Glendale CA unit available Robbins Hobby also Glendale CA r Carignan 39 Glen Road Wilmington MA 01887 rogercar@gisnet RED M FUELSRED NIAiXI tulates Kirk excellent FHS Supply488performance 1st Place FHS803 22Z13fi World Chamnlo Winners AMA Air NationalsUsing spaceage lubrication tecnology op 1997 112A CombatFHS Oil -Bob Mearsquality components developed refined over 1996 FAI Pattern Kirk Gray28 years experience RED MAX fuels 1996 Sportsman Randy Wolfespecially engineered Maximum Performance MAC Scale Aerobatic NationalsPower Protection RED MAX known 1997 Sportsman Michael Kupersold internationally best fuel can IRCHA Helicooter Internationalsuse model engine Fuel model types available planes helicopters boats cars -- racing pattern just fun 1997 10cc TopSpeed Bruce Bennett 1997 10cc TimeToClib Bruce Bennett NAMBA Boat Nationals 1996 A-OPC 35cc Mod Tun Joe Monohan 1996 B-OPC 75cc Mod Tun Don Hirami 1996 C-OPC 11cc Mod Tun Mike McKabney 1996 C-OPC 11cc Stock Tun Joe Monohan Other contests nationwide Numerous awards year FHS Supply lncPO Box 9CloverSC 29710-0009 Sales800 742-8484Voice 803 222-7488 lnternetFHSoil@aolcom Fax803 222-7285 httpllmembersaolcomlFHSoillRedMaxhtml Engine types 2 4 cycle Glow Diesel Nitro Power blends 0% 75% 5% Oil blends RED MAX Synthetic Syn-Cas Blend 0Customer special blends available0 Minimum gal Standard 4-gal 20-qt Cases Shipping UPS door 12 gal motorfreight commercial address Price breaks 412 2060 124 gal Special discount prepaid club orders RED MAX Shirts Hats & Stickers available ge AA CH Electronics headquarters hqht weioht weed trimmer conversions Pdces inclado switch harneno battery 5650 postage & handling All CH $11995 Mcculloch 28/32 Homelite 25/30 Ryobi 26 4031 2c ignitions $18995 Honda 0031 are iuiiy Insc,iteotnmpmnhobmisaoH0Ioaoown,,nmaserviceable EI,micrmmg OpFoo Hi PerOrmac carts motor macro muffle Lutortcraeroacyccresrrcionoowsaoro $9995 HD replacement ignition Bosch plug captor Sacho based angines $14495 HO replacement ignition syocm ttparfr Bosch cap $12495 Zenoab 0-45 G62 Zdd5 Ouick Mount 5yncro sparlr Ignition Hood stags slower/smoother idle bettor top end Reqoirea no machining Mace mere ianiiiwn carts anseries sasilaisla Sarad 53151, nimw list narcarelama November 1998 55 Engines left right Hands GX31 Ryabi 31 llacir 32 ife 25 D & J ELECTRONICS Marigold St NW Hartvllle OH 44632 1236330-877-1445 Ii Service & Repairs Most Radio Control Systems Utilizing Calibrated Test Equipment & Spectrum Analyzers Endors.d AMAi RCMA Sticker Station #105 Futaba Airtronics JR Ace HiTec Tower Cirrus World Engines & WE USE GENUINE FACTORY REPLACEMENT PARTS Complete 1991 Narrow Banding & Upgrades RCD / HITEC R/C DEALER FCC Licensed Speed Control Repairs Quality Service Fast Turn Around Shipping & Insurance Extra UPS Mail Visit hont pagt http//wwwdttIelectronics corn Email davld@dnleIectronicscom jayne@dnjelectronics AMA #256123ARRLWB8YS
Edition: Model Aviation - 1998/11
Page Numbers: 50, 51, 52, 55
THE FOR SS4ESREE SERVO U Richard Carignan 900 -inch Travel {707 inches Ounces Available Force 500 inches-i FIGURE 1 Typical standard servo 900 travel 42 ounce-inches torque one-inch pushrod travel 7 inch arm required 594 ounces force can obtained neutral $ 1800 L7 500 inches 594 Ounces Force inch Travel 84 Ounces _- Available Force 7W FIGURE 2 . Force limited strength linkage servo mechanics locked condition Standard servo 1800 rotation Shorter arm gives higher output force same one-inch travel TODAYS RADIO CONTROL servos have reached remarkable degree function versatility reliability low cost available variety sizes output torque levels satisfy requirements just about RC application Except special fairly expensive servos used sailboat applications devices have rotaly outputs turn 450 covering 900 arc article describes modification increases servo arm rotation 450 900 1800 total actuating force can obtained servos expense reduced transit time modification can either change servo electronics interface device between receiver servo applications reduced transit time concern l80 servo can perform functions using smaller servo size thereby saving weight cost An additional advantage locking action very high output force servo endpoints method servo modification achieve 1800 described Typical servo operation 900 output arm rotation shown Figure 1 values indicated standard servo 42 ounceinches output torque application requires inch total pushrod actuation servo arm length 707 inch required case available force neutral 42 ounce-inches divided 707 inchesa force 594 ounces servo ann rotates away neutral available force increases 450 available force 42/5 unces desirable because force required deflect control surface airstream also increases movement neutral Applications true would flaps servo-actuated retractable landing gear servo neutral position flaps retract landing gear present loads servo reason cases larger higher-torque servos needed applications Figure 2 shows same servo used Figure 1 modification obtain 1800 output 5 inch servo arm length pushrod travel still inch force neutral increased about 40 percent available force neutral now 84 ounces 50 Model Aviation neutral available force increases breaking point servo linkages endpoint locking additional advantage 1800 servo locked condition no additional servo current required maintain actuating force battery drain reduced compared servo setup requires holding current maintain its position flap application Disadvantages 1800 servo rotation Transit time doubled although problem flaps retracts Requires dedicated internal servo modification interface device Pushrod end-to-end travel adjustable changing servo arm length Change feedback voltage method have used successfully several applications first use flaps 1/5-scale Cessna Bird Dog done adding resistors servo feedback pot Schematically Figure 3 shows required modification increase servo travel 90 1800 Total feedback pot resistance across end terminals typically 5000 ohms Addition two resistors end pot reduces output voltage change per degree shaft rotation half Servo modification requires some mechanical simple soldering skills Servos smaller standard size easily modified some have gear travel limits allow 1800 travel following description covers modification standard-size Futaba S3003 servo Prepare clean work area white sheet paper bench works well Remove four screws bottom servo cover will reveal circuit board input lead connections Before removing upper case hold down servo output shaft finger keep internal gears place case lifted carefully may find intermediate gears will come loose small gear pin comes off upper case case replace pin gears may have displaced Connect servo receiver channel center neutral position such elevator set trim center have transmitter has adjustable neutral set neutral standard position 15 ins Switch receiver transmitter Note output gear cog position used Graphic Design Jill Ann Gavanaugh Resistor Added Feedback Pot Regulated Voltage R2 Feedback Pot Resistance 5K ohms 4 Ri Battery Minus FIGURE 3 Modification 1800 rotation requires addition resistors feedback pot shown Resistor values Ri plus R2 total pot resistance See text Ri R2 resistance values Pushrods Z-bends top servo armsrequired 1800 rotation Threaded devises pushrod ends adjustment Voltage Servo Board Slider Moves Servo Arm Pushrods have slight bends servo end applications using servo drive two flaps retracts November 1998 51 Make smaller value resistor offset minus Use larger value offset plus See table below FIGURE 5 RESISTOR TABLE Neutral Offset Angle Degrees o toll 11 26 26 41 Resistor Values K Ohms 27 24 33 18 39 12 Cut outer leads feedback pot leaving /32 inch Trim leads 1/4 watt resistors solder shown sure use high low values proper positions indicated mechanical stop see Figure 4 Switch off receiver transmitter Determine approximate number degrees center output gear cog located An easy way to count number gear teeth away center cog located servos have checked gear has 41 teeth 880 per tooth Record angle note side offset occurs indicated Figure 4 information will used select end resistors location Remove gears noting positions servo has screws holding motor place remove will notice two slots servo case both sides pot shaft keyed output gear provide access two catches hold pot position Since pot connected circuit board short solid leads servo must released catches before board can lifted out have success releasing catches using small jewelers screwdriver two small pieces metal chisel point pressed slot between pot body catches works well small wedges fit between pot body catches pushing catches away pot body Putting slight pressure pot shaft during operation helps release catches pot releases complete servo board motor pot can removed case may need gently pry up circuit board free case use excessive force Referring Figure 5 identify pots two end terminals will left right viewed servo end Cut out section leads leaving about 3/32-inch lengths board pot servos feedback pot nominal 5K ohms resistor values shown Figure 5 table will have scaled proportion pot resistance relative 5K resistance Select resistor values table Figure 5 Except 33K values stocked Radio Shack can obtained special order cannot find resistors need send SASE author will sent no charge supply lasts Trim two selected -watt resistor leads fit between circuit board pot terminal shown Figure 5 Referring Figure 5 select required resistor solder between circuit board pot Trim second lead between pot board solder other resistor place Check soldering job bridges small balls solder may have formed thoroughly clean unit Set pot shaft its midrange position Carefully return unit its case push circuit board make pot body snap catches pot shaft just starts protrude through case pull pot position engage catches using long-nose pliers flats pot shaft Place output gear over pot shaft check its rotation ease motion 52 Model Aviation Minus Output Gear Gear FIGURE 4 Before removing servo cover gears set servo neutral cover removed measure neutral offset angle note direction 1- shown will used select resistor values figure 5 0. i7KO 0 0 0 000 00 PC Board Motor Pot gear cog should positioned pointing case end Figure 4 Reinstall remaining gears pins case covers Connect servo receiver before turn transmitter servo should respond control stick movement controlling channel neutral temporarily attach servo output arm can observe angular output-arm rotation Move control stick see getting 1800 rotation servo shaft moves 1800 hitting stops finished could servo drive gear hitting its stop need adjust transmitter travel Listen carefully servo hitting internal stop will hear servo hum trying go beyond stop servo will also drawing high stall current condition Mechanical setup 1800 servo requires use Z-bend servo end pushrod shown figure 6 enters servo arm top side threaded clevis should used other pushrod end provide adjustment application using servo drive two flaps two retracts Z-bend ends push rods must have slight bend shown figure 7 50 full 180 degree rotation can obtained Use Y connector using two servos same function such left right flaps some cases two servos used single application may necessary reverse rotation servo obtain desired actuation both devices can achieved servo modification purchase reversed servo interface circuit available several sources advertise model publications can make own reverser See MA May 1997 article Brent Dane An interface device between receiver servo increases signal pulse length rate-of-change another method get 80 servo rotation Since seen such unit advertised several companies sell electronic devices searched Internet US Patent Office site relative patents subject search turned up patent February 1997 exactly type device based microcontroller technology inventor Walter S Polan manufactures unit called Servo Genie servo extender also has servo-reversing option developed device part work movie special-effects industry company called Electrofex Glendale CA unit available Robbins Hobby also Glendale CA r Carignan 39 Glen Road Wilmington MA 01887 rogercar@gisnet RED M FUELSRED NIAiXI tulates Kirk excellent FHS Supply488performance 1st Place FHS803 22Z13fi World Chamnlo Winners AMA Air NationalsUsing spaceage 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