George Myers HOW MANY TIMES have hadthat feeling during split-S pullout high-speed dive elevator just wasnt doing its job Kinda gets throat doesnt Lets take look whats happening situation See draw ing below Airspeed high because engine power gravity working together airplane flying nose-high through air because youve got elevator full UP Air approaching wing leading edge below turned wing leaves wing going down its called downwash Thus see air approaches horizontal tail above giving tail angle attack angle adds elevator deflection angle Youthe pilot like because helps pullout elevator servo may agree however because has work harder reach position youve Just much can expect servo enough first part question easiest answer need RC system gallon jug Put hook output wheel servo Lay servo its side edge table Hang gallon jug hook see figure above 1 With hook set below center add some water jug 2 Activate system lift jug 3 If hook hole rises above horizontal let jug down add water 4 Keep repeating steps 2 3 until hole wheel supports hook stops horizontal position 5 Weigh jug water use baby scale C k STREAMLINES OF AIRFLOW An RC model striving avoid ground Itll never make elevator servo cant give enough up Fast airplanes great big ones can overtax servos George presents way help pick appropriate servo 22 Model Aviation Which servos top would choose control Norm Rosenstocks beautiful big WACO HKS-7 bottom month George tells make choiceand fly safe commanded THE HOOK SHOULD BE ABLE 10 REACH TIRS POSiTION WIThOIJT-FIND THE WEIGHT OF WATER THAT JUST STOPS ThE 0 HOOKINTHIS / POSITION STARTINGTABLE TOP TION TO GALLON JUG basic rig George used test servos Lay servo its side edge table other suitable support hook up receiver battery pack increase load hook until servo stalls Calculate its output torqueall plane can get determine radius hole servo output wheel supporting hook put wires holes opposite ends diameter Measure over holes see sketch measure wire Compute radius follows radius over two wires-dia wire 2 torque produced servo computed like torque ht jug water x radius dimensions torque Force x Distance USA servo torques measured inch-ounces multiply pounds water 16 reference Ive tested few large servos term large doesnt have much meaning restricted testing servos like Kraft KPS- 15 results shown table bottom page made no attempt find best servo exists used what could borrow Most used may come up catalog values new servos addition type receiver/decoder condition state charge batteries affects results will obtain Its referenceyoure results may differ point left two questions 1 How fast will model go 2 How strong must servo First lets assume models fastest speed will occur dive estimate dive speed measure fuselage cross-section area its maximum add area exposed cylinder head muffler landing gear add projected area wings tails going compute Q Force/Area divide models takeoff weight area calculated above estimate Q dive Read miles per hour graph below Next going estimate servo torque required start equation Control Surface Hinge Torque F Dont panic its simpler looks symbols equation have following definitions C Geometric average chord control surface inches See Brad Powers Lets Talk About CG MA May 1980 p 23 et seq complete discussion subject thats too much work use maximum chord will con servtive V mated dive speed miles per hour THE TWO-WIRE METHOD FOR FINDING DISTANCE BETWEEN TWO HOLES Use calipers measure across two wires inserted servo output disk Youve got know moment arm get torque data estimated graph step before S rol surface area square inches Remember measure both ailerons both elevators since two surfaces ing driven servo D rol surface deflection angle degrees Continued page 102 4 LOW GLIZER PUSHROD -1 SERVO 0MAXAVR LOADQO ELEVATOR C 4 D s typical geometry used calculate estimated control surface load servo Youll have use formula given text unless take time generate equation yourself simple somebut re-invent wheel PERFORMANCES OF VARIOUS LARGE SERVOS STATICDYNAMIC ManufacturerMechanicsTorque Radius Thrust Stall Idle 900 Free Travel & Typein-oz inlbs ma ma ma sec Ace R/C AtlasDunham D-8455325B75800514050460 ballbaaring Futaba FP-515Futaba386345700420512050488 ball-bearing Kraft KPS-15 IIKraft3363655756001616060516 KraftKPS-20H Kraft 555 365 950 1100 18 160 45 516 ball-bearing World Engines World Engines 310 365 530 390 4 110 50 516 S-i 188 ball bearing World Engines World Engines 315 365 54 450 65 105 40 E16 S-12 ball-bearing World Engines World Engines 1400 585 1500 1750 8 390 55 827 516* ball-bearing *usjng WE 16 AH battery pack Notes 1 The hook inserted outer hole servo wheel 2 Stall current measured meter having insertion resistance 0014 ohms 3 Airplanes equipped World Engines S-12 servos took 1st 2nd 1980 Nationals Las Vegas 4 Quarter-Scale enthusiasts should note specs World Engines 816 vary smooth powerful efficient will need much bigger batteries use no excuse flying 20-pound airplanes two-ounce servos Use servos adequate task fly safely March 1981 23 Use graph estimate models dive speed George tells compute dynamic pressure model dimensions read over line down get speed scheme works balancing aerodynamic dragdue dynamic air pressure against models weight per unit crosssection area firndo PROPELLERS polyester boll color Go GRISH No 1 propeller True helical pitch airfoil win-power 2 Blade Tractor 5-3each 5-4So 35o4Mc 6364SOc 747678Mc 848-68-8c 9-49-69-7 9810-4106needs 11411-6118i 12412-512-8ii 2 BladePusher YOUR DEALER 570-3 3 Blade Pusher Metallic Aluminum 8688 ia 5606104 er 06 $110 Put -in balsa strips just beneath shape same pieces will form point covering edge well permit inser tion pins side lacing Now add in balsa lower fairing strips between wing mounts back ply seat mount piece Add re balsa strips along cabanes sand taper top bottom Install shape pieces balsa block 1 sq abut 72 long firewall front wing mount key piece cowling shape use little time care shape somewhat apparent generally rounded tapered rearward extension firewall front ply covering may now added Approximate patterns shown plans make up patterns cardboard fit required before cutting parts 1/32-in GRISH LARGE WOOD PROPELLERS HARDWOOD too hard minimizes hance costly plane engine damage True pitch airfoil fully finished balanced ready coating 3/8 BOREALL SIZES IN18 $7 6 8 & 10 PITCH 20 8 22 10 24 13 RIGHT HAND TRACTOR Os 6 RUSH ST JOHN INDIANA 46373 ply sheet will minor variances between model another Note slight lip formed edges ply covering Leave itdont sand off way full-scale made Construct install tail skid fittings pivot fitting made brass strip sheet Attach base fitting hardwood stem post using four small sheet metal screws fittings top bottom skid -in brass strip full-scale plane used bungee cord connect front skid upper side fuselage felt better use spring attachment avoid servicing otherwise would necessary Make up install control stick dummy pivot linkage visible below bottom fuselage found -in alumi num tubing best Use short piece rubber tubing control stick handle originally control stick hooked elevator linkage found caused periodic binding elevator desirable affliction dummied off simply ran wire lower end control stick around underseat bearing rod back upper connection stick simulated real controls made stick movable out interference actual controls Fair-in landing gear wires consists sandwich-type construction 1/16-in ply outer pieces 3/16-in balsa inner pieces Epoxy together landing gear wire forming leading edges should sanded round fore aft covering later wrap covering material diagonal striping pattern about p-in intervals per full-scale practice continued Radio Technique/Myers Continued page 23 Measure calculate Ill show A Downwash angle tail degrees Youll have guess about Its about 50 Downwash what causes plane pull itself out dive eventually enough room F An empirical function angle have developed wind tunnel tests Use following values calcula tions A-r-D1015202530 F 000046200005050000545 00005880000630 convert answer servo torque required simply multiply ratio servo wheel arm radius/control horn radius Actually due angles involved conversion requires bit geometry Since basing servo measurements 900 servo motion servo radius full UP 707 x radius measured wheel arm Likewise elevator deflection angle slightly reduces control horn working radius though effect small can usually neglected Therefore estimating purposes can say Sero Torque Required .Courrol Hinge Torque nOY0 Serre radius Conirol H&rnrIdiu Putting together equation STR 7Ll F in-oz U terms L, servo arm radius L2 control horn radius inches Sample Problem Curare elevator I Find dive speed Q Takeoff weight pounds full tank Projected cross-section areas gear retracted Fuselage Cylinder Head Header Tuned Pipe Propeller 170 26 24 15 45 280 squarc inchcs Q 28 pounds/square inch Vd\e 130 mph graph propeller stopped Note Dive speed can actually less equal greater value shown graph depending propeller pitch engine rpm Propeller stopped average sort answer 2 Find servo torque required 102 Model Aviation R EALIS NI SCALE ACCESSORIES WILLIAMS BROTHERS RADIO CONTROL SCALE PILOTS SCALE WHEELS CONTROL-LINECYLINDERS ENGINE KITS MACHINE GUN KITS FREE-FLIGHT STIC DISPLAY MODELS SEND $1 FOR COMPLETE ILLUSTRATED CATALOG DEPT MA 181 PAWNEE STREET SAN MARCOS CA 9 Sizes pitches styles NEWSIZE IN B& 10 PITCH 26 $16 Note Assume use Fourmost Racing Pro ducts Gapless Hinge similar instal lation avoid discussion effect control surface gap significant Control surface deflection angle required pullout dive depends very strongly altitude pullout starts Maximum deflection angle usually chosen basis tlight testing minimum angle reliably produces spin entry Let D case D a Elevator parameters Span nches Chord Area 8 sq V 130 mph D therefore F 588 b Elevator Hinge torque F 130 x 130 x 48 x 2 x 0000588 in-oz 3 Now turn box servos pick likely candidate Try Ace RC Atlas Output wheel radius 325 Stroke half-stroke 1 230 ne D 342 7xL1/L2 325/672 Servo torque required L9T 339 x 955 in-oz Servo torque available in-oz Atlas OK Now can see people get away flying large airplanes small servos use small deflection angles fly level much possible simple static analysis does take account shock vibration factors can increase servo requirements bvfactors four must remember thank flying buddies George Druhak Tom Hunt valuable help developing simplified analysis Next month will take up shock vibration factors will calculate servo size Norm Rosenstocks Waco talk bit about pushrod size strength Later will take up subject larger battery packs required support new larger servos Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicks iille NY 11801 Spruce Goose Jr/Willoughby Continued page 25 flight second transmitter 72240 MHz con trolled rudder elevator flaps ailerons fifth sixth channels operated 18 lights included two landing lights wing between engines 3 4 tween 5 6 plus float called taxi lights John Elliott handled flight transmitter Darrell Meyer performed duties flight engineer though feet still dock Other members ground crew started engines synchronized tach checking high low speeds detailed hang onto rud der full-power check What sweet sound eight engines made Throttled back idle huge silver bird carried deposited upon water could just feel excitement 80or-si helpers spectators bystanders taxied out flight Awesome Power 2I3rds Thirst 1980 Features * Improved By-pass Design * Longer Crankshaft/BearIng * Better Balance * Mark X Carburetor $6495 Bushing Schnuerl can lot active flying far less fuel 40 sized engine compared big 60 Probably popular displacement range R/O flying sites Power spare wealth kit designs available Reasonable cost too Hot Line 5011 646-165e MFG CO 5305 TOWSON AVE FORT SMITH ARK 72901 A uthorizecF DQdIO ervice FACTORYAUTHORIZED SERVICE FOR ALL OF THE FOLLOWING BRANDS Ace Aero Sport Cannon Cirrus Kraft World Engines EK Logictrol Micro Avionics Pro Line Orbit Mathes D&D RS Systems Royal Simprop Jerobee ALSO WARRANTY SERVICE EXPERT SER VICE FOR ALL BRANDS Z Don McCarthy Factory trained technicians over 15 years Radio Control Electronics S HOURS Closed Sun & Mon lOam-S pmWedFri lOam-6 pm Sat lOam-2 pm 714 639-8886 941 N MAIN ST ORANGE CALIFORNIA 92667 first flight no length football field approximating flight original Hercules about 10-ft altitude seemed tu mc flew about scale speed descent like Sail plane landinglong protracted did catch pontoon landing spray stop ping three out eight engines did prevent taxiing back point departure waters edge Nearly $5000 has invested un usual project according Meyer broth ers enthusiastic acclaim crowd smiles faces Team Hercu les after first successful flight made well worthwhile Congratulations surely order accomplishment building flying Spruce Goose Junior Aerial Photography/Lodge Continued page 27 screw removed wheel collar attached its set-screw cable servo arm slides freely over cable until presses against wheel collar Position #1 moves Position #2 slides winder its limit servo arm comes back Position #2 Position #1 spring retum camera winder allows wheel collar cable follow servo back takes about 1 slides advance film cable flexible doesnt matter servo goes Position #2 cable will bend upward slider stops half way wind cycle accomplished throttle March 1981 103 THE FOX 4O-RC
Edition: Model Aviation - 1981/03
Page Numbers: 22, 23, 102, 103
George Myers HOW MANY TIMES have hadthat feeling during split-S pullout high-speed dive elevator just wasnt doing its job Kinda gets throat doesnt Lets take look whats happening situation See draw ing below Airspeed high because engine power gravity working together airplane flying nose-high through air because youve got elevator full UP Air approaching wing leading edge below turned wing leaves wing going down its called downwash Thus see air approaches horizontal tail above giving tail angle attack angle adds elevator deflection angle Youthe pilot like because helps pullout elevator servo may agree however because has work harder reach position youve Just much can expect servo enough first part question easiest answer need RC system gallon jug Put hook output wheel servo Lay servo its side edge table Hang gallon jug hook see figure above 1 With hook set below center add some water jug 2 Activate system lift jug 3 If hook hole rises above horizontal let jug down add water 4 Keep repeating steps 2 3 until hole wheel supports hook stops horizontal position 5 Weigh jug water use baby scale C k STREAMLINES OF AIRFLOW An RC model striving avoid ground Itll never make elevator servo cant give enough up Fast airplanes great big ones can overtax servos George presents way help pick appropriate servo 22 Model Aviation Which servos top would choose control Norm Rosenstocks beautiful big WACO HKS-7 bottom month George tells make choiceand fly safe commanded THE HOOK SHOULD BE ABLE 10 REACH TIRS POSiTION WIThOIJT-FIND THE WEIGHT OF WATER THAT JUST STOPS ThE 0 HOOKINTHIS / POSITION STARTINGTABLE TOP TION TO GALLON JUG basic rig George used test servos Lay servo its side edge table other suitable support hook up receiver battery pack increase load hook until servo stalls Calculate its output torqueall plane can get determine radius hole servo output wheel supporting hook put wires holes opposite ends diameter Measure over holes see sketch measure wire Compute radius follows radius over two wires-dia wire 2 torque produced servo computed like torque ht jug water x radius dimensions torque Force x Distance USA servo torques measured inch-ounces multiply pounds water 16 reference Ive tested few large servos term large doesnt have much meaning restricted testing servos like Kraft KPS- 15 results shown table bottom page made no attempt find best servo exists used what could borrow Most used may come up catalog values new servos addition type receiver/decoder condition state charge batteries affects results will obtain Its referenceyoure results may differ point left two questions 1 How fast will model go 2 How strong must servo First lets assume models fastest speed will occur dive estimate dive speed measure fuselage cross-section area its maximum add area exposed cylinder head muffler landing gear add projected area wings tails going compute Q Force/Area divide models takeoff weight area calculated above estimate Q dive Read miles per hour graph below Next going estimate servo torque required start equation Control Surface Hinge Torque F Dont panic its simpler looks symbols equation have following definitions C Geometric average chord control surface inches See Brad Powers Lets Talk About CG MA May 1980 p 23 et seq complete discussion subject thats too much work use maximum chord will con servtive V mated dive speed miles per hour THE TWO-WIRE METHOD FOR FINDING DISTANCE BETWEEN TWO HOLES Use calipers measure across two wires inserted servo output disk Youve got know moment arm get torque data estimated graph step before S rol surface area square inches Remember measure both ailerons both elevators since two surfaces ing driven servo D rol surface deflection angle degrees Continued page 102 4 LOW GLIZER PUSHROD -1 SERVO 0MAXAVR LOADQO ELEVATOR C 4 D s typical geometry used calculate estimated control surface load servo Youll have use formula given text unless take time generate equation yourself simple somebut re-invent wheel PERFORMANCES OF VARIOUS LARGE SERVOS STATICDYNAMIC ManufacturerMechanicsTorque Radius Thrust Stall Idle 900 Free Travel & Typein-oz inlbs ma ma ma sec Ace R/C AtlasDunham D-8455325B75800514050460 ballbaaring Futaba FP-515Futaba386345700420512050488 ball-bearing Kraft KPS-15 IIKraft3363655756001616060516 KraftKPS-20H Kraft 555 365 950 1100 18 160 45 516 ball-bearing World Engines World Engines 310 365 530 390 4 110 50 516 S-i 188 ball bearing World Engines World Engines 315 365 54 450 65 105 40 E16 S-12 ball-bearing World Engines World Engines 1400 585 1500 1750 8 390 55 827 516* ball-bearing *usjng WE 16 AH battery pack Notes 1 The hook inserted outer hole servo wheel 2 Stall current measured meter having insertion resistance 0014 ohms 3 Airplanes equipped World Engines S-12 servos took 1st 2nd 1980 Nationals Las Vegas 4 Quarter-Scale enthusiasts should note specs World Engines 816 vary smooth powerful efficient will need much bigger batteries use no excuse flying 20-pound airplanes two-ounce servos Use servos adequate task fly safely March 1981 23 Use graph estimate models dive speed George tells compute dynamic pressure model dimensions read over line down get speed scheme works balancing aerodynamic dragdue dynamic air pressure against models weight per unit crosssection area firndo PROPELLERS polyester boll color Go GRISH No 1 propeller True helical pitch airfoil win-power 2 Blade Tractor 5-3each 5-4So 35o4Mc 6364SOc 747678Mc 848-68-8c 9-49-69-7 9810-4106needs 11411-6118i 12412-512-8ii 2 BladePusher YOUR DEALER 570-3 3 Blade Pusher Metallic Aluminum 8688 ia 5606104 er 06 $110 Put -in balsa strips just beneath shape same pieces will form point covering edge well permit inser tion pins side lacing Now add in balsa lower fairing strips between wing mounts back ply seat mount piece Add re balsa strips along cabanes sand taper top bottom Install shape pieces balsa block 1 sq abut 72 long firewall front wing mount key piece cowling shape use little time care shape somewhat apparent generally rounded tapered rearward extension firewall front ply covering may now added Approximate patterns shown plans make up patterns cardboard fit required before cutting parts 1/32-in GRISH LARGE WOOD PROPELLERS HARDWOOD too hard minimizes hance costly plane engine damage True pitch airfoil fully finished balanced ready coating 3/8 BOREALL SIZES IN18 $7 6 8 & 10 PITCH 20 8 22 10 24 13 RIGHT HAND TRACTOR Os 6 RUSH ST JOHN INDIANA 46373 ply sheet will minor variances between model another Note slight lip formed edges ply covering Leave itdont sand off way full-scale made Construct install tail skid fittings pivot fitting made brass strip sheet Attach base fitting hardwood stem post using four small sheet metal screws fittings top bottom skid -in brass strip full-scale plane used bungee cord connect front skid upper side fuselage felt better use spring attachment avoid servicing otherwise would necessary Make up install control stick dummy pivot linkage visible below bottom fuselage found -in alumi num tubing best Use short piece rubber tubing control stick handle originally control stick hooked elevator linkage found caused periodic binding elevator desirable affliction dummied off simply ran wire lower end control stick around underseat bearing rod back upper connection stick simulated real controls made stick movable out interference actual controls Fair-in landing gear wires consists sandwich-type construction 1/16-in ply outer pieces 3/16-in balsa inner pieces Epoxy together landing gear wire forming leading edges should sanded round fore aft covering later wrap covering material diagonal striping pattern about p-in intervals per full-scale practice continued Radio Technique/Myers Continued page 23 Measure calculate Ill show A Downwash angle tail degrees Youll have guess about Its about 50 Downwash what causes plane pull itself out dive eventually enough room F An empirical function angle have developed wind tunnel tests Use following values calcula tions A-r-D1015202530 F 000046200005050000545 00005880000630 convert answer servo torque required simply multiply ratio servo wheel arm radius/control horn radius Actually due angles involved conversion requires bit geometry Since basing servo measurements 900 servo motion servo radius full UP 707 x radius measured wheel arm Likewise elevator deflection angle slightly reduces control horn working radius though effect small can usually neglected Therefore estimating purposes can say Sero Torque Required .Courrol Hinge Torque nOY0 Serre radius Conirol H&rnrIdiu Putting together equation STR 7Ll F in-oz U terms L, servo arm radius L2 control horn radius inches Sample Problem Curare elevator I Find dive speed Q Takeoff weight pounds full tank Projected cross-section areas gear retracted Fuselage Cylinder Head Header Tuned Pipe Propeller 170 26 24 15 45 280 squarc inchcs Q 28 pounds/square inch Vd\e 130 mph graph propeller stopped Note Dive speed can actually less equal greater value shown graph depending propeller pitch engine rpm Propeller stopped average sort answer 2 Find servo torque required 102 Model Aviation R EALIS NI SCALE ACCESSORIES WILLIAMS BROTHERS RADIO CONTROL SCALE PILOTS SCALE WHEELS CONTROL-LINECYLINDERS ENGINE KITS MACHINE GUN KITS FREE-FLIGHT STIC DISPLAY MODELS SEND $1 FOR COMPLETE ILLUSTRATED CATALOG DEPT MA 181 PAWNEE STREET SAN MARCOS CA 9 Sizes pitches styles NEWSIZE IN B& 10 PITCH 26 $16 Note Assume use Fourmost Racing Pro ducts Gapless Hinge similar instal lation avoid discussion effect control surface gap significant Control surface deflection angle required pullout dive depends very strongly altitude pullout starts Maximum deflection angle usually chosen basis tlight testing minimum angle reliably produces spin entry Let D case D a Elevator parameters Span nches Chord Area 8 sq V 130 mph D therefore F 588 b Elevator Hinge torque F 130 x 130 x 48 x 2 x 0000588 in-oz 3 Now turn box servos pick likely candidate Try Ace RC Atlas Output wheel radius 325 Stroke half-stroke 1 230 ne D 342 7xL1/L2 325/672 Servo torque required L9T 339 x 955 in-oz Servo torque available in-oz Atlas OK Now can see people get away flying large airplanes small servos use small deflection angles fly level much possible simple static analysis does take account shock vibration factors can increase servo requirements bvfactors four must remember thank flying buddies George Druhak Tom Hunt valuable help developing simplified analysis Next month will take up shock vibration factors will calculate servo size Norm Rosenstocks Waco talk bit about pushrod size strength Later will take up subject larger battery packs required support new larger servos Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicks iille NY 11801 Spruce Goose Jr/Willoughby Continued page 25 flight second transmitter 72240 MHz con trolled rudder elevator flaps ailerons fifth sixth channels operated 18 lights included two landing lights wing between engines 3 4 tween 5 6 plus float called taxi lights John Elliott handled flight transmitter Darrell Meyer performed duties flight engineer though feet still dock Other members ground crew started engines synchronized tach checking high low speeds detailed hang onto rud der full-power check What sweet sound eight engines made Throttled back idle huge silver bird carried deposited upon water could just feel excitement 80or-si helpers spectators bystanders taxied out flight Awesome Power 2I3rds Thirst 1980 Features * Improved By-pass Design * Longer Crankshaft/BearIng * Better Balance * Mark X Carburetor $6495 Bushing Schnuerl can lot active flying far less fuel 40 sized engine compared big 60 Probably popular displacement range R/O flying sites Power spare wealth kit designs available Reasonable cost too Hot Line 5011 646-165e MFG CO 5305 TOWSON AVE FORT SMITH ARK 72901 A uthorizecF DQdIO ervice FACTORYAUTHORIZED SERVICE FOR ALL OF THE FOLLOWING BRANDS Ace Aero Sport Cannon Cirrus Kraft World Engines EK Logictrol Micro Avionics Pro Line Orbit Mathes D&D RS Systems Royal Simprop Jerobee ALSO WARRANTY SERVICE EXPERT SER VICE FOR ALL BRANDS Z Don McCarthy Factory trained technicians over 15 years Radio Control Electronics S HOURS Closed Sun & Mon lOam-S pmWedFri lOam-6 pm Sat lOam-2 pm 714 639-8886 941 N MAIN ST ORANGE CALIFORNIA 92667 first flight no length football field approximating flight original Hercules about 10-ft altitude seemed tu mc flew about scale speed descent like Sail plane landinglong protracted did catch pontoon landing spray stop ping three out eight engines did prevent taxiing back point departure waters edge Nearly $5000 has invested un usual project according Meyer broth ers enthusiastic acclaim crowd smiles faces Team Hercu les after first successful flight made well worthwhile Congratulations surely order accomplishment building flying Spruce Goose Junior Aerial Photography/Lodge Continued page 27 screw removed wheel collar attached its set-screw cable servo arm slides freely over cable until presses against wheel collar Position #1 moves Position #2 slides winder its limit servo arm comes back Position #2 Position #1 spring retum camera winder allows wheel collar cable follow servo back takes about 1 slides advance film cable flexible doesnt matter servo goes Position #2 cable will bend upward slider stops half way wind cycle accomplished throttle March 1981 103 THE FOX 4O-RC
Edition: Model Aviation - 1981/03
Page Numbers: 22, 23, 102, 103
George Myers HOW MANY TIMES have hadthat feeling during split-S pullout high-speed dive elevator just wasnt doing its job Kinda gets throat doesnt Lets take look whats happening situation See draw ing below Airspeed high because engine power gravity working together airplane flying nose-high through air because youve got elevator full UP Air approaching wing leading edge below turned wing leaves wing going down its called downwash Thus see air approaches horizontal tail above giving tail angle attack angle adds elevator deflection angle Youthe pilot like because helps pullout elevator servo may agree however because has work harder reach position youve Just much can expect servo enough first part question easiest answer need RC system gallon jug Put hook output wheel servo Lay servo its side edge table Hang gallon jug hook see figure above 1 With hook set below center add some water jug 2 Activate system lift jug 3 If hook hole rises above horizontal let jug down add water 4 Keep repeating steps 2 3 until hole wheel supports hook stops horizontal position 5 Weigh jug water use baby scale C k STREAMLINES OF AIRFLOW An RC model striving avoid ground Itll never make elevator servo cant give enough up Fast airplanes great big ones can overtax servos George presents way help pick appropriate servo 22 Model Aviation Which servos top would choose control Norm Rosenstocks beautiful big WACO HKS-7 bottom month George tells make choiceand fly safe commanded THE HOOK SHOULD BE ABLE 10 REACH TIRS POSiTION WIThOIJT-FIND THE WEIGHT OF WATER THAT JUST STOPS ThE 0 HOOKINTHIS / POSITION STARTINGTABLE TOP TION TO GALLON JUG basic rig George used test servos Lay servo its side edge table other suitable support hook up receiver battery pack increase load hook until servo stalls Calculate its output torqueall plane can get determine radius hole servo output wheel supporting hook put wires holes opposite ends diameter Measure over holes see sketch measure wire Compute radius follows radius over two wires-dia wire 2 torque produced servo computed like torque ht jug water x radius dimensions torque Force x Distance USA servo torques measured inch-ounces multiply pounds water 16 reference Ive tested few large servos term large doesnt have much meaning restricted testing servos like Kraft KPS- 15 results shown table bottom page made no attempt find best servo exists used what could borrow Most used may come up catalog values new servos addition type receiver/decoder condition state charge batteries affects results will obtain Its referenceyoure results may differ point left two questions 1 How fast will model go 2 How strong must servo First lets assume models fastest speed will occur dive estimate dive speed measure fuselage cross-section area its maximum add area exposed cylinder head muffler landing gear add projected area wings tails going compute Q Force/Area divide models takeoff weight area calculated above estimate Q dive Read miles per hour graph below Next going estimate servo torque required start equation Control Surface Hinge Torque F Dont panic its simpler looks symbols equation have following definitions C Geometric average chord control surface inches See Brad Powers Lets Talk About CG MA May 1980 p 23 et seq complete discussion subject thats too much work use maximum chord will con servtive V mated dive speed miles per hour THE TWO-WIRE METHOD FOR FINDING DISTANCE BETWEEN TWO HOLES Use calipers measure across two wires inserted servo output disk Youve got know moment arm get torque data estimated graph step before S rol surface area square inches Remember measure both ailerons both elevators since two surfaces ing driven servo D rol surface deflection angle degrees Continued page 102 4 LOW GLIZER PUSHROD -1 SERVO 0MAXAVR LOADQO ELEVATOR C 4 D s typical geometry used calculate estimated control surface load servo Youll have use formula given text unless take time generate equation yourself simple somebut re-invent wheel PERFORMANCES OF VARIOUS LARGE SERVOS STATICDYNAMIC ManufacturerMechanicsTorque Radius Thrust Stall Idle 900 Free Travel & Typein-oz inlbs ma ma ma sec Ace R/C AtlasDunham D-8455325B75800514050460 ballbaaring Futaba FP-515Futaba386345700420512050488 ball-bearing Kraft KPS-15 IIKraft3363655756001616060516 KraftKPS-20H Kraft 555 365 950 1100 18 160 45 516 ball-bearing World Engines World Engines 310 365 530 390 4 110 50 516 S-i 188 ball bearing World Engines World Engines 315 365 54 450 65 105 40 E16 S-12 ball-bearing World Engines World Engines 1400 585 1500 1750 8 390 55 827 516* ball-bearing *usjng WE 16 AH battery pack Notes 1 The hook inserted outer hole servo wheel 2 Stall current measured meter having insertion resistance 0014 ohms 3 Airplanes equipped World Engines S-12 servos took 1st 2nd 1980 Nationals Las Vegas 4 Quarter-Scale enthusiasts should note specs World Engines 816 vary smooth powerful efficient will need much bigger batteries use no excuse flying 20-pound airplanes two-ounce servos Use servos adequate task fly safely March 1981 23 Use graph estimate models dive speed George tells compute dynamic pressure model dimensions read over line down get speed scheme works balancing aerodynamic dragdue dynamic air pressure against models weight per unit crosssection area firndo PROPELLERS polyester boll color Go GRISH No 1 propeller True helical pitch airfoil win-power 2 Blade Tractor 5-3each 5-4So 35o4Mc 6364SOc 747678Mc 848-68-8c 9-49-69-7 9810-4106needs 11411-6118i 12412-512-8ii 2 BladePusher YOUR DEALER 570-3 3 Blade Pusher Metallic Aluminum 8688 ia 5606104 er 06 $110 Put -in balsa strips just beneath shape same pieces will form point covering edge well permit inser tion pins side lacing Now add in balsa lower fairing strips between wing mounts back ply seat mount piece Add re balsa strips along cabanes sand taper top bottom Install shape pieces balsa block 1 sq abut 72 long firewall front wing mount key piece cowling shape use little time care shape somewhat apparent generally rounded tapered rearward extension firewall front ply covering may now added Approximate patterns shown plans make up patterns cardboard fit required before cutting parts 1/32-in GRISH LARGE WOOD PROPELLERS HARDWOOD too hard minimizes hance costly plane engine damage True pitch airfoil fully finished balanced ready coating 3/8 BOREALL SIZES IN18 $7 6 8 & 10 PITCH 20 8 22 10 24 13 RIGHT HAND TRACTOR Os 6 RUSH ST JOHN INDIANA 46373 ply sheet will minor variances between model another Note slight lip formed edges ply covering Leave itdont sand off way full-scale made Construct install tail skid fittings pivot fitting made brass strip sheet Attach base fitting hardwood stem post using four small sheet metal screws fittings top bottom skid -in brass strip full-scale plane used bungee cord connect front skid upper side fuselage felt better use spring attachment avoid servicing otherwise would necessary Make up install control stick dummy pivot linkage visible below bottom fuselage found -in alumi num tubing best Use short piece rubber tubing control stick handle originally control stick hooked elevator linkage found caused periodic binding elevator desirable affliction dummied off simply ran wire lower end control stick around underseat bearing rod back upper connection stick simulated real controls made stick movable out interference actual controls Fair-in landing gear wires consists sandwich-type construction 1/16-in ply outer pieces 3/16-in balsa inner pieces Epoxy together landing gear wire forming leading edges should sanded round fore aft covering later wrap covering material diagonal striping pattern about p-in intervals per full-scale practice continued Radio Technique/Myers Continued page 23 Measure calculate Ill show A Downwash angle tail degrees Youll have guess about Its about 50 Downwash what causes plane pull itself out dive eventually enough room F An empirical function angle have developed wind tunnel tests Use following values calcula tions A-r-D1015202530 F 000046200005050000545 00005880000630 convert answer servo torque required simply multiply ratio servo wheel arm radius/control horn radius Actually due angles involved conversion requires bit geometry Since basing servo measurements 900 servo motion servo radius full UP 707 x radius measured wheel arm Likewise elevator deflection angle slightly reduces control horn working radius though effect small can usually neglected Therefore estimating purposes can say Sero Torque Required .Courrol Hinge Torque nOY0 Serre radius Conirol H&rnrIdiu Putting together equation STR 7Ll F in-oz U terms L, servo arm radius L2 control horn radius inches Sample Problem Curare elevator I Find dive speed Q Takeoff weight pounds full tank Projected cross-section areas gear retracted Fuselage Cylinder Head Header Tuned Pipe Propeller 170 26 24 15 45 280 squarc inchcs Q 28 pounds/square inch Vd\e 130 mph graph propeller stopped Note Dive speed can actually less equal greater value shown graph depending propeller pitch engine rpm Propeller stopped average sort answer 2 Find servo torque required 102 Model Aviation R EALIS NI SCALE ACCESSORIES WILLIAMS BROTHERS RADIO CONTROL SCALE PILOTS SCALE WHEELS CONTROL-LINECYLINDERS ENGINE KITS MACHINE GUN KITS FREE-FLIGHT STIC DISPLAY MODELS SEND $1 FOR COMPLETE ILLUSTRATED CATALOG DEPT MA 181 PAWNEE STREET SAN MARCOS CA 9 Sizes pitches styles NEWSIZE IN B& 10 PITCH 26 $16 Note Assume use Fourmost Racing Pro ducts Gapless Hinge similar instal lation avoid discussion effect control surface gap significant Control surface deflection angle required pullout dive depends very strongly altitude pullout starts Maximum deflection angle usually chosen basis tlight testing minimum angle reliably produces spin entry Let D case D a Elevator parameters Span nches Chord Area 8 sq V 130 mph D therefore F 588 b Elevator Hinge torque F 130 x 130 x 48 x 2 x 0000588 in-oz 3 Now turn box servos pick likely candidate Try Ace RC Atlas Output wheel radius 325 Stroke half-stroke 1 230 ne D 342 7xL1/L2 325/672 Servo torque required L9T 339 x 955 in-oz Servo torque available in-oz Atlas OK Now can see people get away flying large airplanes small servos use small deflection angles fly level much possible simple static analysis does take account shock vibration factors can increase servo requirements bvfactors four must remember thank flying buddies George Druhak Tom Hunt valuable help developing simplified analysis Next month will take up shock vibration factors will calculate servo size Norm Rosenstocks Waco talk bit about pushrod size strength Later will take up subject larger battery packs required support new larger servos Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicks iille NY 11801 Spruce Goose Jr/Willoughby Continued page 25 flight second transmitter 72240 MHz con trolled rudder elevator flaps ailerons fifth sixth channels operated 18 lights included two landing lights wing between engines 3 4 tween 5 6 plus float called taxi lights John Elliott handled flight transmitter Darrell Meyer performed duties flight engineer though feet still dock Other members ground crew started engines synchronized tach checking high low speeds detailed hang onto rud der full-power check What sweet sound eight engines made Throttled back idle huge silver bird carried deposited upon water could just feel excitement 80or-si helpers spectators bystanders taxied out flight Awesome Power 2I3rds Thirst 1980 Features * Improved By-pass Design * Longer Crankshaft/BearIng * Better Balance * Mark X Carburetor $6495 Bushing Schnuerl can lot active flying far less fuel 40 sized engine compared big 60 Probably popular displacement range R/O flying sites Power spare wealth kit designs available Reasonable cost too Hot Line 5011 646-165e MFG CO 5305 TOWSON AVE FORT SMITH ARK 72901 A uthorizecF DQdIO ervice FACTORYAUTHORIZED SERVICE FOR ALL OF THE FOLLOWING BRANDS Ace Aero Sport Cannon Cirrus Kraft World Engines EK Logictrol Micro Avionics Pro Line Orbit Mathes D&D RS Systems Royal Simprop Jerobee ALSO WARRANTY SERVICE EXPERT SER VICE FOR ALL BRANDS Z Don McCarthy Factory trained technicians over 15 years Radio Control Electronics S HOURS Closed Sun & Mon lOam-S pmWedFri lOam-6 pm Sat lOam-2 pm 714 639-8886 941 N MAIN ST ORANGE CALIFORNIA 92667 first flight no length football field approximating flight original Hercules about 10-ft altitude seemed tu mc flew about scale speed descent like Sail plane landinglong protracted did catch pontoon landing spray stop ping three out eight engines did prevent taxiing back point departure waters edge Nearly $5000 has invested un usual project according Meyer broth ers enthusiastic acclaim crowd smiles faces Team Hercu les after first successful flight made well worthwhile Congratulations surely order accomplishment building flying Spruce Goose Junior Aerial Photography/Lodge Continued page 27 screw removed wheel collar attached its set-screw cable servo arm slides freely over cable until presses against wheel collar Position #1 moves Position #2 slides winder its limit servo arm comes back Position #2 Position #1 spring retum camera winder allows wheel collar cable follow servo back takes about 1 slides advance film cable flexible doesnt matter servo goes Position #2 cable will bend upward slider stops half way wind cycle accomplished throttle March 1981 103 THE FOX 4O-RC
Edition: Model Aviation - 1981/03
Page Numbers: 22, 23, 102, 103
George Myers HOW MANY TIMES have hadthat feeling during split-S pullout high-speed dive elevator just wasnt doing its job Kinda gets throat doesnt Lets take look whats happening situation See draw ing below Airspeed high because engine power gravity working together airplane flying nose-high through air because youve got elevator full UP Air approaching wing leading edge below turned wing leaves wing going down its called downwash Thus see air approaches horizontal tail above giving tail angle attack angle adds elevator deflection angle Youthe pilot like because helps pullout elevator servo may agree however because has work harder reach position youve Just much can expect servo enough first part question easiest answer need RC system gallon jug Put hook output wheel servo Lay servo its side edge table Hang gallon jug hook see figure above 1 With hook set below center add some water jug 2 Activate system lift jug 3 If hook hole rises above horizontal let jug down add water 4 Keep repeating steps 2 3 until hole wheel supports hook stops horizontal position 5 Weigh jug water use baby scale C k STREAMLINES OF AIRFLOW An RC model striving avoid ground Itll never make elevator servo cant give enough up Fast airplanes great big ones can overtax servos George presents way help pick appropriate servo 22 Model Aviation Which servos top would choose control Norm Rosenstocks beautiful big WACO HKS-7 bottom month George tells make choiceand fly safe commanded THE HOOK SHOULD BE ABLE 10 REACH TIRS POSiTION WIThOIJT-FIND THE WEIGHT OF WATER THAT JUST STOPS ThE 0 HOOKINTHIS / POSITION STARTINGTABLE TOP TION TO GALLON JUG basic rig George used test servos Lay servo its side edge table other suitable support hook up receiver battery pack increase load hook until servo stalls Calculate its output torqueall plane can get determine radius hole servo output wheel supporting hook put wires holes opposite ends diameter Measure over holes see sketch measure wire Compute radius follows radius over two wires-dia wire 2 torque produced servo computed like torque ht jug water x radius dimensions torque Force x Distance USA servo torques measured inch-ounces multiply pounds water 16 reference Ive tested few large servos term large doesnt have much meaning restricted testing servos like Kraft KPS- 15 results shown table bottom page made no attempt find best servo exists used what could borrow Most used may come up catalog values new servos addition type receiver/decoder condition state charge batteries affects results will obtain Its referenceyoure results may differ point left two questions 1 How fast will model go 2 How strong must servo First lets assume models fastest speed will occur dive estimate dive speed measure fuselage cross-section area its maximum add area exposed cylinder head muffler landing gear add projected area wings tails going compute Q Force/Area divide models takeoff weight area calculated above estimate Q dive Read miles per hour graph below Next going estimate servo torque required start equation Control Surface Hinge Torque F Dont panic its simpler looks symbols equation have following definitions C Geometric average chord control surface inches See Brad Powers Lets Talk About CG MA May 1980 p 23 et seq complete discussion subject thats too much work use maximum chord will con servtive V mated dive speed miles per hour THE TWO-WIRE METHOD FOR FINDING DISTANCE BETWEEN TWO HOLES Use calipers measure across two wires inserted servo output disk Youve got know moment arm get torque data estimated graph step before S rol surface area square inches Remember measure both ailerons both elevators since two surfaces ing driven servo D rol surface deflection angle degrees Continued page 102 4 LOW GLIZER PUSHROD -1 SERVO 0MAXAVR LOADQO ELEVATOR C 4 D s typical geometry used calculate estimated control surface load servo Youll have use formula given text unless take time generate equation yourself simple somebut re-invent wheel PERFORMANCES OF VARIOUS LARGE SERVOS STATICDYNAMIC ManufacturerMechanicsTorque Radius Thrust Stall Idle 900 Free Travel & Typein-oz inlbs ma ma ma sec Ace R/C AtlasDunham D-8455325B75800514050460 ballbaaring Futaba FP-515Futaba386345700420512050488 ball-bearing Kraft KPS-15 IIKraft3363655756001616060516 KraftKPS-20H Kraft 555 365 950 1100 18 160 45 516 ball-bearing World Engines World Engines 310 365 530 390 4 110 50 516 S-i 188 ball bearing World Engines World Engines 315 365 54 450 65 105 40 E16 S-12 ball-bearing World Engines World Engines 1400 585 1500 1750 8 390 55 827 516* ball-bearing *usjng WE 16 AH battery pack Notes 1 The hook inserted outer hole servo wheel 2 Stall current measured meter having insertion resistance 0014 ohms 3 Airplanes equipped World Engines S-12 servos took 1st 2nd 1980 Nationals Las Vegas 4 Quarter-Scale enthusiasts should note specs World Engines 816 vary smooth powerful efficient will need much bigger batteries use no excuse flying 20-pound airplanes two-ounce servos Use servos adequate task fly safely March 1981 23 Use graph estimate models dive speed George tells compute dynamic pressure model dimensions read over line down get speed scheme works balancing aerodynamic dragdue dynamic air pressure against models weight per unit crosssection area firndo PROPELLERS polyester boll color Go GRISH No 1 propeller True helical pitch airfoil win-power 2 Blade Tractor 5-3each 5-4So 35o4Mc 6364SOc 747678Mc 848-68-8c 9-49-69-7 9810-4106needs 11411-6118i 12412-512-8ii 2 BladePusher YOUR DEALER 570-3 3 Blade Pusher Metallic Aluminum 8688 ia 5606104 er 06 $110 Put -in balsa strips just beneath shape same pieces will form point covering edge well permit inser tion pins side lacing Now add in balsa lower fairing strips between wing mounts back ply seat mount piece Add re balsa strips along cabanes sand taper top bottom Install shape pieces balsa block 1 sq abut 72 long firewall front wing mount key piece cowling shape use little time care shape somewhat apparent generally rounded tapered rearward extension firewall front ply covering may now added Approximate patterns shown plans make up patterns cardboard fit required before cutting parts 1/32-in GRISH LARGE WOOD PROPELLERS HARDWOOD too hard minimizes hance costly plane engine damage True pitch airfoil fully finished balanced ready coating 3/8 BOREALL SIZES IN18 $7 6 8 & 10 PITCH 20 8 22 10 24 13 RIGHT HAND TRACTOR Os 6 RUSH ST JOHN INDIANA 46373 ply sheet will minor variances between model another Note slight lip formed edges ply covering Leave itdont sand off way full-scale made Construct install tail skid fittings pivot fitting made brass strip sheet Attach base fitting hardwood stem post using four small sheet metal screws fittings top bottom skid -in brass strip full-scale plane used bungee cord connect front skid upper side fuselage felt better use spring attachment avoid servicing otherwise would necessary Make up install control stick dummy pivot linkage visible below bottom fuselage found -in alumi num tubing best Use short piece rubber tubing control stick handle originally control stick hooked elevator linkage found caused periodic binding elevator desirable affliction dummied off simply ran wire lower end control stick around underseat bearing rod back upper connection stick simulated real controls made stick movable out interference actual controls Fair-in landing gear wires consists sandwich-type construction 1/16-in ply outer pieces 3/16-in balsa inner pieces Epoxy together landing gear wire forming leading edges should sanded round fore aft covering later wrap covering material diagonal striping pattern about p-in intervals per full-scale practice continued Radio Technique/Myers Continued page 23 Measure calculate Ill show A Downwash angle tail degrees Youll have guess about Its about 50 Downwash what causes plane pull itself out dive eventually enough room F An empirical function angle have developed wind tunnel tests Use following values calcula tions A-r-D1015202530 F 000046200005050000545 00005880000630 convert answer servo torque required simply multiply ratio servo wheel arm radius/control horn radius Actually due angles involved conversion requires bit geometry Since basing servo measurements 900 servo motion servo radius full UP 707 x radius measured wheel arm Likewise elevator deflection angle slightly reduces control horn working radius though effect small can usually neglected Therefore estimating purposes can say Sero Torque Required .Courrol Hinge Torque nOY0 Serre radius Conirol H&rnrIdiu Putting together equation STR 7Ll F in-oz U terms L, servo arm radius L2 control horn radius inches Sample Problem Curare elevator I Find dive speed Q Takeoff weight pounds full tank Projected cross-section areas gear retracted Fuselage Cylinder Head Header Tuned Pipe Propeller 170 26 24 15 45 280 squarc inchcs Q 28 pounds/square inch Vd\e 130 mph graph propeller stopped Note Dive speed can actually less equal greater value shown graph depending propeller pitch engine rpm Propeller stopped average sort answer 2 Find servo torque required 102 Model Aviation R EALIS NI SCALE ACCESSORIES WILLIAMS BROTHERS RADIO CONTROL SCALE PILOTS SCALE WHEELS CONTROL-LINECYLINDERS ENGINE KITS MACHINE GUN KITS FREE-FLIGHT STIC DISPLAY MODELS SEND $1 FOR COMPLETE ILLUSTRATED CATALOG DEPT MA 181 PAWNEE STREET SAN MARCOS CA 9 Sizes pitches styles NEWSIZE IN B& 10 PITCH 26 $16 Note Assume use Fourmost Racing Pro ducts Gapless Hinge similar instal lation avoid discussion effect control surface gap significant Control surface deflection angle required pullout dive depends very strongly altitude pullout starts Maximum deflection angle usually chosen basis tlight testing minimum angle reliably produces spin entry Let D case D a Elevator parameters Span nches Chord Area 8 sq V 130 mph D therefore F 588 b Elevator Hinge torque F 130 x 130 x 48 x 2 x 0000588 in-oz 3 Now turn box servos pick likely candidate Try Ace RC Atlas Output wheel radius 325 Stroke half-stroke 1 230 ne D 342 7xL1/L2 325/672 Servo torque required L9T 339 x 955 in-oz Servo torque available in-oz Atlas OK Now can see people get away flying large airplanes small servos use small deflection angles fly level much possible simple static analysis does take account shock vibration factors can increase servo requirements bvfactors four must remember thank flying buddies George Druhak Tom Hunt valuable help developing simplified analysis Next month will take up shock vibration factors will calculate servo size Norm Rosenstocks Waco talk bit about pushrod size strength Later will take up subject larger battery packs required support new larger servos Keep letters flowing George M Myers 70 Froehlich Farm Rd Hicks iille NY 11801 Spruce Goose Jr/Willoughby Continued page 25 flight second transmitter 72240 MHz con trolled rudder elevator flaps ailerons fifth sixth channels operated 18 lights included two landing lights wing between engines 3 4 tween 5 6 plus float called taxi lights John Elliott handled flight transmitter Darrell Meyer performed duties flight engineer though feet still dock Other members ground crew started engines synchronized tach checking high low speeds detailed hang onto rud der full-power check What sweet sound eight engines made Throttled back idle huge silver bird carried deposited upon water could just feel excitement 80or-si helpers spectators bystanders taxied out flight Awesome Power 2I3rds Thirst 1980 Features * Improved By-pass Design * Longer Crankshaft/BearIng * Better Balance * Mark X Carburetor $6495 Bushing Schnuerl can lot active flying far less fuel 40 sized engine compared big 60 Probably popular displacement range R/O flying sites Power spare wealth kit designs available Reasonable cost too Hot Line 5011 646-165e MFG CO 5305 TOWSON AVE FORT SMITH ARK 72901 A uthorizecF DQdIO ervice FACTORYAUTHORIZED SERVICE FOR ALL OF THE FOLLOWING BRANDS Ace Aero Sport Cannon Cirrus Kraft World Engines EK Logictrol Micro Avionics Pro Line Orbit Mathes D&D RS Systems Royal Simprop Jerobee ALSO WARRANTY SERVICE EXPERT SER VICE FOR ALL BRANDS Z Don McCarthy Factory trained technicians over 15 years Radio Control Electronics S HOURS Closed Sun & Mon lOam-S pmWedFri lOam-6 pm Sat lOam-2 pm 714 639-8886 941 N MAIN ST ORANGE CALIFORNIA 92667 first flight no length football field approximating flight original Hercules about 10-ft altitude seemed tu mc flew about scale speed descent like Sail plane landinglong protracted did catch pontoon landing spray stop ping three out eight engines did prevent taxiing back point departure waters edge Nearly $5000 has invested un usual project according Meyer broth ers enthusiastic acclaim crowd smiles faces Team Hercu les after first successful flight made well worthwhile Congratulations surely order accomplishment building flying Spruce Goose Junior Aerial Photography/Lodge Continued page 27 screw removed wheel collar attached its set-screw cable servo arm slides freely over cable until presses against wheel collar Position #1 moves Position #2 slides winder its limit servo arm comes back Position #2 Position #1 spring retum camera winder allows wheel collar cable follow servo back takes about 1 slides advance film cable flexible doesnt matter servo goes Position #2 cable will bend upward slider stops half way wind cycle accomplished throttle March 1981 103 THE FOX 4O-RC