MIDWEST CL Models Give choose from. theres Midwest model al kind CL flyer desires MAUIUIRFI 50 Engine Sizes 29 35 Wing Span 48 Greatest U Control stunt flyer trainer Easy build easier flyKit No 235 MAGICIAN 15 Engine Sizes 15 19 Wing Span 34 Little brother Magician 35 Kit No 215 WARHAWK Engine Sizes 29 35 Wing Span 48 Kit No 244 Engine Sizes Kit No 242 15 to 19 Wing Span 33 PRODUCTCO 400 South Indiana St Hobart IndIana 46342 1TGEbff letters to-lIT editor SM T ER letters will carefully considered general interest used Send Model Aviation 815 15th St N W Washington DC 20005 Canard Controversy Appreciated Charles Bair Jrs ar ticle entitled Case Canard However neglected point out important aerodynamic cases against canard ward mounted stabilizer must oper ate higher lift coefficient wing produces downwash downwash affects quite large portion center section main wing reduces its L/D measurably Also remember Aero Engineer ing lectures properly believe canard less sensitive wider range center gravity movement course advantage canard especially have carry shifty cargo like say crop duster might Jim Noffsinger AMA 95919 Lynchburg VA .. would like offer some comments about article Case Ca nard Although Mr Bair somewhat dismayed fact engineers havent done canard configuration should consider following 1 Canard well suited handling powerful negative moment produced flaps SAAB SF37 ing delta has no flaps conventional configuration tail aft flaps produce sizeable downwash increment loads horizontal tail produce favorable moment balance flap 2 Stability varies pretty much square tail moment arm about CG case canard direc tional stability therefore greatly reduced since distance CG fin very small comparison 3 long forebody destabilizing both pitch yaw Real aircraft designed cri terion paramount above others.. safety comments regarding desir ability placing CG aft center pressure wing conventional aircraft absurd Such arrangement provides no recovery stall pro duces dynamic instability makes airplane extremely difficult fly Finally should review French.. canard means duck French ca nard configuration named because resembles duck its long outstretched neck broad bill Bradford W Powers AMA 66044 San Diego CA Mr Powers former Senior Design Engineer Preliminary Design Con vair Both Mr Bair author Case Canard Mr Sanders codesigner Zonker Mr Bair prominent aeronautical engineers Both respond below Mr Powers Mr Noffsingers comments As cor rect definition word canard caption own French dictionary shows us firm ground Reader letters give everyone oppor tunity feedback better insight world aerodynamics Actually very little aerodynamics black white can find advantages dis advantages configuration canard otherwise designer makes trade-offs try get best performance intended use design Which better F-4 Diamant sailplane answer Jim Noffsinger canard stabilizer indeed operates higher lift coefficient requirement stable airframe Also forward stabiliz er does immerse center section wing downwash L/D wing probably will decrease perform ance aircraft whole wing-body tail important concept both wing stabilizer lifting canard aircraft L/D should higher equivalent conventional aircraft wing lifts tail pushes down big question much difference design will have different effects must analyzed wind tunnel tested find relative magnitudes differ ences measured L/D 13 canard design wind tunnel test Sailplanes 19 above fighters significantly lower 3 4 As far CG range same equations design principles govern both conven tional canard configurations Results same either type answer Mr Powers flaps can de velop powerful nose down moment de pending deflection size placement wing Flaps generally used decrease takeoff landing distances help keep jet engines higher thrust level during landing Airplanes 4 Model Aviation KING COBRA Engine Sizes 29 35 Wing Span 48 Kit No 236 Engine Sizes 15 19 Wing Span 33 Kit No 243 low wing loadings general aviation model aircraft handle very nicely flaps could benefit canard con figuration canard can also handle flaps within limits its control power stability equations directional stability depends what called ver tical tail volume product vertical tail area times distance CG CG moved stability varies lin early distance square distance does present prob lem canard distance CG small half con ventional design solution crease dimension vertical tail keep tail volume unchanged retain same degree directional stability general anything front CG including prop has destabilizing fluence canard simply has de stabilizing surface area front CG Using stability equations vertical tail volume sized provide required de gree directional stability CG located forward provide sufficient longi tudinal stability Mr Powers will take close look longitudinal static stability equation will find increases horizontal tail volume aircraft neutral point moves rearward conventional airplane can move trailing edge wing center pressure sym metrical wing located very near quarter chord neutral point trailing edge CG could located d would provide 25% static margin quite stable having CG behind center pressure Some model designs have flown way quite some time take advantage upload tail rather nor mal download airplanes quite stable through stall uploaded tail provides stabilizing influence Regarding word canard Cassells New French Dictionary lists several mean ings among duck drake false news hoax canard resembles duck its long outstretched neck also people especially Wright Brothers time dont believe canards fly hence either definition fits well Frenchman originated term would best source accuracy however absence choice yours Milt Sanders Fairborn OH Milt Sanders kind enough answer questions about canard article business trip few own comments response Jim Noffsingers letter would like add canard downwash tip vortex can interact advan tageously wing flow field See tached information SAAB response Bradford Powers letter 1 SAAB Viggen does have elevons its delta wings function flaps ATT CONTEST MODELERS offering several items direct basis wholesalers care stock due limited appeal Fox 29 version Combat Special produces about 1 HP @ 21000 RPM 60% nitro e $4495 Fox 40 ase fitted meehan ite piston Faster stock Can fitted carb choice Throttle Model6495 Std Intake Model 495 Stunt 35 ed hardened cyl hard piston Price2595 Cyl & Piston . . 800 Fox 19 ed cyl having twb additional by-passesRuns faster stock Throttle Model3395 Std Intake Model 595 Cyl & Piston 000 above items call 501-646-1656 or write us directly NEW ITEMS YOU SHOULD TRY Control line flyers should aware Fox Bell Cranks ones will reliably withstand 100 lb pull test Reason made 063 hard alum compe titors 051 soft Small bell crank 86778 Large bell crank 86779 anding configuration both sides deflect down reference SAAB attached 2 formula yaw stiffness Cnn contributed vertical stabilizer alone avSvlv_ C n Swbw av curve slope vertical stabi lizer vertical stabilizer lvdistance CG center pressure vertical stabilizer 5w wing Fox Glow Plug Taps made use production High speed steel precision ground 71432 1/32 Tap $1000 Fox FILL Fuel Bulb Fills its full 4 oz S seconds Heavy wall Ideal filling bladder tanks 30500 fits Pint & Qt cans 30501 fits Gal cans 195 Fox Medium Profile Fuel Tanks brand new shape contains baffle outlet side can run close engine Choice 6 lengths 275 Fox Fuel Line silicone line almost twice strong nearest competitor Try skeptical surgical tubing made specs has heavy wall does collapse Small Surgical Tubing Med Surgical Tubing e Surgical Tubing Small Tuffline silicone Med Tuffline silicone Large Tuffline silicone 25 Ft 25 Ft 25 Ft 55 Ft 70 Ft 100 Ft Fox 90303 Tuned Muffler will gain about 700 RPM 60 Universal adapter fits Webra OS Enya Tigre KB well FOX Eagle & Hawk Most effective 11714 prop stock priced $2495 FX MANUFACTURING COMPANY 5305 Towson Fort Smith AR 72901 wing ttail efficiency ection sidewash point made lv linear term squared 3 Bradford Powers correct ever canard airplane can designed stable both pitch yaw must consider entire airplane just destabilizing components Placing center gravity con ventional airplane aft center pres sure wing 25% mean aerodynamic chord untwisted symmetric wing Continued page 57 June 1977 5 Letters Editor continued page 5 lj NOSE WING VORTEX MAIN W9IG VORTEII Excerpt SAAB Tech Report obtain high lift coefficients low speeds canard flap deflected generating lift front center gravity requires downward elevon deflec tion trim adds other lift forces indicated.. such used RC pattern ships absurd example plans Phoenix 6 find center pressure wing 580 inches aft leading edge vertex used Schrink Method accounting spanwise load distribution plans show recommended CG location 675 inches aft leading edge vertex inch aft center pressure wing airplane balanced described recovers quite nicely stalls spins Charles Hair Jr Xenia OH Man-Powered Info Thank consistently excellent quality Model viation especially en joyed coverage manpowered air craft Icarus March 1977 Man poweran Update April 1976 need help finding official rules Henry Kremer manpowered aircraft con test have address Mr Kremer know source can get information help would greatly appreciated Thank again coverage topic Model via tion Lane Kagey AMA 11735 Fullerton CA Man Powered Flight Regulations Conditions 50000 Kremer Com petition available Royal Aero nautical Society 4 Hamilton P1 London WIV OEQ England Na tional Aeronautic Assoc 815 15th St N W Washington DC 20005 Mr Ka gey has already received copy Solar Power First Astro Flight first build fly solar-powered RC airplane Astro Flight Model 7404 Sunrise first flew Sept 17 1974 under battery power first solar-powered flight took place Nov 4 1974 longest highest flight took place vehicle 02 Sept 27 1975 flight lasted 3 hrs 25 mm vehicle reached altitude 17200 ft enclosed report photos can used correct erroneous impression Graupner plane first Robert Boucher Pres Astro Flight Inc Venice CA Model 7404 built under Air Force contract Its wing span 32 ft its ser vice ceiling greater 50000 ft Power single 6-hp permanent magnet motor speed reducer 30-in propeller Power generated four solar arrays affixed upper wing surface capa ble generating 570 watts Rudder elevator used takeoff landing navigation rudder out sight Sun sensing used heading reference model intended demonstrate possibility indefinitely long flights extreme altitudes climbing high enough during day able glide night freeing class air vehicles limi tation offossilfuels best can offer few days endurance Climb rate 100 400 fps depending sunlight sink less ift per sec Maude Taits GeeBee Model V Am enclosing picture second GeeBee Model Y Sportster flown Maude Tait flew model past seasons Sport Scale contests won eight trophies Really flies great Flew Nats first Dayton Interesting thing about photo taken Springfield Mass front original GeeBee hangar still exists Airport gone now shop ping center Henry Haflke Vineland NJ Henrys plans GeeBee Model Y appeared March 1976 issue Plans still available No 131 $500 1st RC Masters Class 1st RC Advanced 1st RC Novice 1st RC Sport Scale 1st Formula Pylon 1st Quarter Midget Pylon 1st CL Stunt Open 1st CL Stunt Senior 1st CL Stunt Junior 1st CL Combat O & Sr 1st CL Slow Comb Op & Sr 1st CL Carrier II Op Jr Sr 1st CL Carrier Jr & Sr 1st CL Class D Speed Open 1st CL Class C Speed Jr & Sr 1st CLCIassB Speed Op & Sr 1st CL Cl Speed Op Sr Jr 1st CL Formula 40 Open 1st CL Class B Proto Jr 1st FF Class B Open 1st FF Class C Open HIGH PERFORMANCE * COMPETITION PROVEN * THIN RIGID BLADES O HARD MAPLE WOOD * SUPERBLY FINISHED COMPlEtELY FUEL PIOOF SPECIAL PRO SERIES 2 FOR RC-FREE FLIGHT CONTROL LINE DIAPITCHPRICE 5%3469 63489 73344tie 83%4 56129 94566% 77%139 10467149 106W 8W149 106EV4159 114677% 7%7%6159 116EW169 11%67169 126179 125W179 1356219 1456249 1556309 164%6389 VII VVIDE BLADE EW EXTRA WIDE SERIES 400 B FOR SPEEDS RACING ADVANCED DESIGN NO 1 IN PYLON RACING LEADING SPEED RECORD HOLDER OP ALL TIMES RC PYLON RACING DIA PITCH PRICE 5%3%4119 7 55%6 129 7 SN 5%N 65129 8% 6%6%7 7/,7%169 9 647 7%7%169 CONTROL LINE SPEEDS RACING DIA PITCH PRICE 4%6%7119 4%55%119 6 788%129 7 7% 10% 11139 8 69149 89N9%N149 8% 77%149 9 12 13199 N NARROW June 1977 57 OUT-PERFORMS ALL OTHERS AT THE 1976 NATIONALS
Edition: Model Aviation - 1977/06
Page Numbers: 4, 5, 57
MIDWEST CL Models Give choose from. theres Midwest model al kind CL flyer desires MAUIUIRFI 50 Engine Sizes 29 35 Wing Span 48 Greatest U Control stunt flyer trainer Easy build easier flyKit No 235 MAGICIAN 15 Engine Sizes 15 19 Wing Span 34 Little brother Magician 35 Kit No 215 WARHAWK Engine Sizes 29 35 Wing Span 48 Kit No 244 Engine Sizes Kit No 242 15 to 19 Wing Span 33 PRODUCTCO 400 South Indiana St Hobart IndIana 46342 1TGEbff letters to-lIT editor SM T ER letters will carefully considered general interest used Send Model Aviation 815 15th St N W Washington DC 20005 Canard Controversy Appreciated Charles Bair Jrs ar ticle entitled Case Canard However neglected point out important aerodynamic cases against canard ward mounted stabilizer must oper ate higher lift coefficient wing produces downwash downwash affects quite large portion center section main wing reduces its L/D measurably Also remember Aero Engineer ing lectures properly believe canard less sensitive wider range center gravity movement course advantage canard especially have carry shifty cargo like say crop duster might Jim Noffsinger AMA 95919 Lynchburg VA .. would like offer some comments about article Case Ca nard Although Mr Bair somewhat dismayed fact engineers havent done canard configuration should consider following 1 Canard well suited handling powerful negative moment produced flaps SAAB SF37 ing delta has no flaps conventional configuration tail aft flaps produce sizeable downwash increment loads horizontal tail produce favorable moment balance flap 2 Stability varies pretty much square tail moment arm about CG case canard direc tional stability therefore greatly reduced since distance CG fin very small comparison 3 long forebody destabilizing both pitch yaw Real aircraft designed cri terion paramount above others.. safety comments regarding desir ability placing CG aft center pressure wing conventional aircraft absurd Such arrangement provides no recovery stall pro duces dynamic instability makes airplane extremely difficult fly Finally should review French.. canard means duck French ca nard configuration named because resembles duck its long outstretched neck broad bill Bradford W Powers AMA 66044 San Diego CA Mr Powers former Senior Design Engineer Preliminary Design Con vair Both Mr Bair author Case Canard Mr Sanders codesigner Zonker Mr Bair prominent aeronautical engineers Both respond below Mr Powers Mr Noffsingers comments As cor rect definition word canard caption own French dictionary shows us firm ground Reader letters give everyone oppor tunity feedback better insight world aerodynamics Actually very little aerodynamics black white can find advantages dis advantages configuration canard otherwise designer makes trade-offs try get best performance intended use design Which better F-4 Diamant sailplane answer Jim Noffsinger canard stabilizer indeed operates higher lift coefficient requirement stable airframe Also forward stabiliz er does immerse center section wing downwash L/D wing probably will decrease perform ance aircraft whole wing-body tail important concept both wing stabilizer lifting canard aircraft L/D should higher equivalent conventional aircraft wing lifts tail pushes down big question much difference design will have different effects must analyzed wind tunnel tested find relative magnitudes differ ences measured L/D 13 canard design wind tunnel test Sailplanes 19 above fighters significantly lower 3 4 As far CG range same equations design principles govern both conven tional canard configurations Results same either type answer Mr Powers flaps can de velop powerful nose down moment de pending deflection size placement wing Flaps generally used decrease takeoff landing distances help keep jet engines higher thrust level during landing Airplanes 4 Model Aviation KING COBRA Engine Sizes 29 35 Wing Span 48 Kit No 236 Engine Sizes 15 19 Wing Span 33 Kit No 243 low wing loadings general aviation model aircraft handle very nicely flaps could benefit canard con figuration canard can also handle flaps within limits its control power stability equations directional stability depends what called ver tical tail volume product vertical tail area times distance CG CG moved stability varies lin early distance square distance does present prob lem canard distance CG small half con ventional design solution crease dimension vertical tail keep tail volume unchanged retain same degree directional stability general anything front CG including prop has destabilizing fluence canard simply has de stabilizing surface area front CG Using stability equations vertical tail volume sized provide required de gree directional stability CG located forward provide sufficient longi tudinal stability Mr Powers will take close look longitudinal static stability equation will find increases horizontal tail volume aircraft neutral point moves rearward conventional airplane can move trailing edge wing center pressure sym metrical wing located very near quarter chord neutral point trailing edge CG could located d would provide 25% static margin quite stable having CG behind center pressure Some model designs have flown way quite some time take advantage upload tail rather nor mal download airplanes quite stable through stall uploaded tail provides stabilizing influence Regarding word canard Cassells New French Dictionary lists several mean ings among duck drake false news hoax canard resembles duck its long outstretched neck also people especially Wright Brothers time dont believe canards fly hence either definition fits well Frenchman originated term would best source accuracy however absence choice yours Milt Sanders Fairborn OH Milt Sanders kind enough answer questions about canard article business trip few own comments response Jim Noffsingers letter would like add canard downwash tip vortex can interact advan tageously wing flow field See tached information SAAB response Bradford Powers letter 1 SAAB Viggen does have elevons its delta wings function flaps ATT CONTEST MODELERS offering several items direct basis wholesalers care stock due limited appeal Fox 29 version Combat Special produces about 1 HP @ 21000 RPM 60% nitro e $4495 Fox 40 ase fitted meehan ite piston Faster stock Can fitted carb choice Throttle Model6495 Std Intake Model 495 Stunt 35 ed hardened cyl hard piston Price2595 Cyl & Piston . . 800 Fox 19 ed cyl having twb additional by-passesRuns faster stock Throttle Model3395 Std Intake Model 595 Cyl & Piston 000 above items call 501-646-1656 or write us directly NEW ITEMS YOU SHOULD TRY Control line flyers should aware Fox Bell Cranks ones will reliably withstand 100 lb pull test Reason made 063 hard alum compe titors 051 soft Small bell crank 86778 Large bell crank 86779 anding configuration both sides deflect down reference SAAB attached 2 formula yaw stiffness Cnn contributed vertical stabilizer alone avSvlv_ C n Swbw av curve slope vertical stabi lizer vertical stabilizer lvdistance CG center pressure vertical stabilizer 5w wing Fox Glow Plug Taps made use production High speed steel precision ground 71432 1/32 Tap $1000 Fox FILL Fuel Bulb Fills its full 4 oz S seconds Heavy wall Ideal filling bladder tanks 30500 fits Pint & Qt cans 30501 fits Gal cans 195 Fox Medium Profile Fuel Tanks brand new shape contains baffle outlet side can run close engine Choice 6 lengths 275 Fox Fuel Line silicone line almost twice strong nearest competitor Try skeptical surgical tubing made specs has heavy wall does collapse Small Surgical Tubing Med Surgical Tubing e Surgical Tubing Small Tuffline silicone Med Tuffline silicone Large Tuffline silicone 25 Ft 25 Ft 25 Ft 55 Ft 70 Ft 100 Ft Fox 90303 Tuned Muffler will gain about 700 RPM 60 Universal adapter fits Webra OS Enya Tigre KB well FOX Eagle & Hawk Most effective 11714 prop stock priced $2495 FX MANUFACTURING COMPANY 5305 Towson Fort Smith AR 72901 wing ttail efficiency ection sidewash point made lv linear term squared 3 Bradford Powers correct ever canard airplane can designed stable both pitch yaw must consider entire airplane just destabilizing components Placing center gravity con ventional airplane aft center pres sure wing 25% mean aerodynamic chord untwisted symmetric wing Continued page 57 June 1977 5 Letters Editor continued page 5 lj NOSE WING VORTEX MAIN W9IG VORTEII Excerpt SAAB Tech Report obtain high lift coefficients low speeds canard flap deflected generating lift front center gravity requires downward elevon deflec tion trim adds other lift forces indicated.. such used RC pattern ships absurd example plans Phoenix 6 find center pressure wing 580 inches aft leading edge vertex used Schrink Method accounting spanwise load distribution plans show recommended CG location 675 inches aft leading edge vertex inch aft center pressure wing airplane balanced described recovers quite nicely stalls spins Charles Hair Jr Xenia OH Man-Powered Info Thank consistently excellent quality Model viation especially en joyed coverage manpowered air craft Icarus March 1977 Man poweran Update April 1976 need help finding official rules Henry Kremer manpowered aircraft con test have address Mr Kremer know source can get information help would greatly appreciated Thank again coverage topic Model via tion Lane Kagey AMA 11735 Fullerton CA Man Powered Flight Regulations Conditions 50000 Kremer Com petition available Royal Aero nautical Society 4 Hamilton P1 London WIV OEQ England Na tional Aeronautic Assoc 815 15th St N W Washington DC 20005 Mr Ka gey has already received copy Solar Power First Astro Flight first build fly solar-powered RC airplane Astro Flight Model 7404 Sunrise first flew Sept 17 1974 under battery power first solar-powered flight took place Nov 4 1974 longest highest flight took place vehicle 02 Sept 27 1975 flight lasted 3 hrs 25 mm vehicle reached altitude 17200 ft enclosed report photos can used correct erroneous impression Graupner plane first Robert Boucher Pres Astro Flight Inc Venice CA Model 7404 built under Air Force contract Its wing span 32 ft its ser vice ceiling greater 50000 ft Power single 6-hp permanent magnet motor speed reducer 30-in propeller Power generated four solar arrays affixed upper wing surface capa ble generating 570 watts Rudder elevator used takeoff landing navigation rudder out sight Sun sensing used heading reference model intended demonstrate possibility indefinitely long flights extreme altitudes climbing high enough during day able glide night freeing class air vehicles limi tation offossilfuels best can offer few days endurance Climb rate 100 400 fps depending sunlight sink less ift per sec Maude Taits GeeBee Model V Am enclosing picture second GeeBee Model Y Sportster flown Maude Tait flew model past seasons Sport Scale contests won eight trophies Really flies great Flew Nats first Dayton Interesting thing about photo taken Springfield Mass front original GeeBee hangar still exists Airport gone now shop ping center Henry Haflke Vineland NJ Henrys plans GeeBee Model Y appeared March 1976 issue Plans still available No 131 $500 1st RC Masters Class 1st RC Advanced 1st RC Novice 1st RC Sport Scale 1st Formula Pylon 1st Quarter Midget Pylon 1st CL Stunt Open 1st CL Stunt Senior 1st CL Stunt Junior 1st CL Combat O & Sr 1st CL Slow Comb Op & Sr 1st CL Carrier II Op Jr Sr 1st CL Carrier Jr & Sr 1st CL Class D Speed Open 1st CL Class C Speed Jr & Sr 1st CLCIassB Speed Op & Sr 1st CL Cl Speed Op Sr Jr 1st CL Formula 40 Open 1st CL Class B Proto Jr 1st FF Class B Open 1st FF Class C Open HIGH PERFORMANCE * COMPETITION PROVEN * THIN RIGID BLADES O HARD MAPLE WOOD * SUPERBLY FINISHED COMPlEtELY FUEL PIOOF SPECIAL PRO SERIES 2 FOR RC-FREE FLIGHT CONTROL LINE DIAPITCHPRICE 5%3469 63489 73344tie 83%4 56129 94566% 77%139 10467149 106W 8W149 106EV4159 114677% 7%7%6159 116EW169 11%67169 126179 125W179 1356219 1456249 1556309 164%6389 VII VVIDE BLADE EW EXTRA WIDE SERIES 400 B FOR SPEEDS RACING ADVANCED DESIGN NO 1 IN PYLON RACING LEADING SPEED RECORD HOLDER OP ALL TIMES RC PYLON RACING DIA PITCH PRICE 5%3%4119 7 55%6 129 7 SN 5%N 65129 8% 6%6%7 7/,7%169 9 647 7%7%169 CONTROL LINE SPEEDS RACING DIA PITCH PRICE 4%6%7119 4%55%119 6 788%129 7 7% 10% 11139 8 69149 89N9%N149 8% 77%149 9 12 13199 N NARROW June 1977 57 OUT-PERFORMS ALL OTHERS AT THE 1976 NATIONALS
Edition: Model Aviation - 1977/06
Page Numbers: 4, 5, 57
MIDWEST CL Models Give choose from. theres Midwest model al kind CL flyer desires MAUIUIRFI 50 Engine Sizes 29 35 Wing Span 48 Greatest U Control stunt flyer trainer Easy build easier flyKit No 235 MAGICIAN 15 Engine Sizes 15 19 Wing Span 34 Little brother Magician 35 Kit No 215 WARHAWK Engine Sizes 29 35 Wing Span 48 Kit No 244 Engine Sizes Kit No 242 15 to 19 Wing Span 33 PRODUCTCO 400 South Indiana St Hobart IndIana 46342 1TGEbff letters to-lIT editor SM T ER letters will carefully considered general interest used Send Model Aviation 815 15th St N W Washington DC 20005 Canard Controversy Appreciated Charles Bair Jrs ar ticle entitled Case Canard However neglected point out important aerodynamic cases against canard ward mounted stabilizer must oper ate higher lift coefficient wing produces downwash downwash affects quite large portion center section main wing reduces its L/D measurably Also remember Aero Engineer ing lectures properly believe canard less sensitive wider range center gravity movement course advantage canard especially have carry shifty cargo like say crop duster might Jim Noffsinger AMA 95919 Lynchburg VA .. would like offer some comments about article Case Ca nard Although Mr Bair somewhat dismayed fact engineers havent done canard configuration should consider following 1 Canard well suited handling powerful negative moment produced flaps SAAB SF37 ing delta has no flaps conventional configuration tail aft flaps produce sizeable downwash increment loads horizontal tail produce favorable moment balance flap 2 Stability varies pretty much square tail moment arm about CG case canard direc tional stability therefore greatly reduced since distance CG fin very small comparison 3 long forebody destabilizing both pitch yaw Real aircraft designed cri terion paramount above others.. safety comments regarding desir ability placing CG aft center pressure wing conventional aircraft absurd Such arrangement provides no recovery stall pro duces dynamic instability makes airplane extremely difficult fly Finally should review French.. canard means duck French ca nard configuration named because resembles duck its long outstretched neck broad bill Bradford W Powers AMA 66044 San Diego CA Mr Powers former Senior Design Engineer Preliminary Design Con vair Both Mr Bair author Case Canard Mr Sanders codesigner Zonker Mr Bair prominent aeronautical engineers Both respond below Mr Powers Mr Noffsingers comments As cor rect definition word canard caption own French dictionary shows us firm ground Reader letters give everyone oppor tunity feedback better insight world aerodynamics Actually very little aerodynamics black white can find advantages dis advantages configuration canard otherwise designer makes trade-offs try get best performance intended use design Which better F-4 Diamant sailplane answer Jim Noffsinger canard stabilizer indeed operates higher lift coefficient requirement stable airframe Also forward stabiliz er does immerse center section wing downwash L/D wing probably will decrease perform ance aircraft whole wing-body tail important concept both wing stabilizer lifting canard aircraft L/D should higher equivalent conventional aircraft wing lifts tail pushes down big question much difference design will have different effects must analyzed wind tunnel tested find relative magnitudes differ ences measured L/D 13 canard design wind tunnel test Sailplanes 19 above fighters significantly lower 3 4 As far CG range same equations design principles govern both conven tional canard configurations Results same either type answer Mr Powers flaps can de velop powerful nose down moment de pending deflection size placement wing Flaps generally used decrease takeoff landing distances help keep jet engines higher thrust level during landing Airplanes 4 Model Aviation KING COBRA Engine Sizes 29 35 Wing Span 48 Kit No 236 Engine Sizes 15 19 Wing Span 33 Kit No 243 low wing loadings general aviation model aircraft handle very nicely flaps could benefit canard con figuration canard can also handle flaps within limits its control power stability equations directional stability depends what called ver tical tail volume product vertical tail area times distance CG CG moved stability varies lin early distance square distance does present prob lem canard distance CG small half con ventional design solution crease dimension vertical tail keep tail volume unchanged retain same degree directional stability general anything front CG including prop has destabilizing fluence canard simply has de stabilizing surface area front CG Using stability equations vertical tail volume sized provide required de gree directional stability CG located forward provide sufficient longi tudinal stability Mr Powers will take close look longitudinal static stability equation will find increases horizontal tail volume aircraft neutral point moves rearward conventional airplane can move trailing edge wing center pressure sym metrical wing located very near quarter chord neutral point trailing edge CG could located d would provide 25% static margin quite stable having CG behind center pressure Some model designs have flown way quite some time take advantage upload tail rather nor mal download airplanes quite stable through stall uploaded tail provides stabilizing influence Regarding word canard Cassells New French Dictionary lists several mean ings among duck drake false news hoax canard resembles duck its long outstretched neck also people especially Wright Brothers time dont believe canards fly hence either definition fits well Frenchman originated term would best source accuracy however absence choice yours Milt Sanders Fairborn OH Milt Sanders kind enough answer questions about canard article business trip few own comments response Jim Noffsingers letter would like add canard downwash tip vortex can interact advan tageously wing flow field See tached information SAAB response Bradford Powers letter 1 SAAB Viggen does have elevons its delta wings function flaps ATT CONTEST MODELERS offering several items direct basis wholesalers care stock due limited appeal Fox 29 version Combat Special produces about 1 HP @ 21000 RPM 60% nitro e $4495 Fox 40 ase fitted meehan ite piston Faster stock Can fitted carb choice Throttle Model6495 Std Intake Model 495 Stunt 35 ed hardened cyl hard piston Price2595 Cyl & Piston . . 800 Fox 19 ed cyl having twb additional by-passesRuns faster stock Throttle Model3395 Std Intake Model 595 Cyl & Piston 000 above items call 501-646-1656 or write us directly NEW ITEMS YOU SHOULD TRY Control line flyers should aware Fox Bell Cranks ones will reliably withstand 100 lb pull test Reason made 063 hard alum compe titors 051 soft Small bell crank 86778 Large bell crank 86779 anding configuration both sides deflect down reference SAAB attached 2 formula yaw stiffness Cnn contributed vertical stabilizer alone avSvlv_ C n Swbw av curve slope vertical stabi lizer vertical stabilizer lvdistance CG center pressure vertical stabilizer 5w wing Fox Glow Plug Taps made use production High speed steel precision ground 71432 1/32 Tap $1000 Fox FILL Fuel Bulb Fills its full 4 oz S seconds Heavy wall Ideal filling bladder tanks 30500 fits Pint & Qt cans 30501 fits Gal cans 195 Fox Medium Profile Fuel Tanks brand new shape contains baffle outlet side can run close engine Choice 6 lengths 275 Fox Fuel Line silicone line almost twice strong nearest competitor Try skeptical surgical tubing made specs has heavy wall does collapse Small Surgical Tubing Med Surgical Tubing e Surgical Tubing Small Tuffline silicone Med Tuffline silicone Large Tuffline silicone 25 Ft 25 Ft 25 Ft 55 Ft 70 Ft 100 Ft Fox 90303 Tuned Muffler will gain about 700 RPM 60 Universal adapter fits Webra OS Enya Tigre KB well FOX Eagle & Hawk Most effective 11714 prop stock priced $2495 FX MANUFACTURING COMPANY 5305 Towson Fort Smith AR 72901 wing ttail efficiency ection sidewash point made lv linear term squared 3 Bradford Powers correct ever canard airplane can designed stable both pitch yaw must consider entire airplane just destabilizing components Placing center gravity con ventional airplane aft center pres sure wing 25% mean aerodynamic chord untwisted symmetric wing Continued page 57 June 1977 5 Letters Editor continued page 5 lj NOSE WING VORTEX MAIN W9IG VORTEII Excerpt SAAB Tech Report obtain high lift coefficients low speeds canard flap deflected generating lift front center gravity requires downward elevon deflec tion trim adds other lift forces indicated.. such used RC pattern ships absurd example plans Phoenix 6 find center pressure wing 580 inches aft leading edge vertex used Schrink Method accounting spanwise load distribution plans show recommended CG location 675 inches aft leading edge vertex inch aft center pressure wing airplane balanced described recovers quite nicely stalls spins Charles Hair Jr Xenia OH Man-Powered Info Thank consistently excellent quality Model viation especially en joyed coverage manpowered air craft Icarus March 1977 Man poweran Update April 1976 need help finding official rules Henry Kremer manpowered aircraft con test have address Mr Kremer know source can get information help would greatly appreciated Thank again coverage topic Model via tion Lane Kagey AMA 11735 Fullerton CA Man Powered Flight Regulations Conditions 50000 Kremer Com petition available Royal Aero nautical Society 4 Hamilton P1 London WIV OEQ England Na tional Aeronautic Assoc 815 15th St N W Washington DC 20005 Mr Ka gey has already received copy Solar Power First Astro Flight first build fly solar-powered RC airplane Astro Flight Model 7404 Sunrise first flew Sept 17 1974 under battery power first solar-powered flight took place Nov 4 1974 longest highest flight took place vehicle 02 Sept 27 1975 flight lasted 3 hrs 25 mm vehicle reached altitude 17200 ft enclosed report photos can used correct erroneous impression Graupner plane first Robert Boucher Pres Astro Flight Inc Venice CA Model 7404 built under Air Force contract Its wing span 32 ft its ser vice ceiling greater 50000 ft Power single 6-hp permanent magnet motor speed reducer 30-in propeller Power generated four solar arrays affixed upper wing surface capa ble generating 570 watts Rudder elevator used takeoff landing navigation rudder out sight Sun sensing used heading reference model intended demonstrate possibility indefinitely long flights extreme altitudes climbing high enough during day able glide night freeing class air vehicles limi tation offossilfuels best can offer few days endurance Climb rate 100 400 fps depending sunlight sink less ift per sec Maude Taits GeeBee Model V Am enclosing picture second GeeBee Model Y Sportster flown Maude Tait flew model past seasons Sport Scale contests won eight trophies Really flies great Flew Nats first Dayton Interesting thing about photo taken Springfield Mass front original GeeBee hangar still exists Airport gone now shop ping center Henry Haflke Vineland NJ Henrys plans GeeBee Model Y appeared March 1976 issue Plans still available No 131 $500 1st RC Masters Class 1st RC Advanced 1st RC Novice 1st RC Sport Scale 1st Formula Pylon 1st Quarter Midget Pylon 1st CL Stunt Open 1st CL Stunt Senior 1st CL Stunt Junior 1st CL Combat O & Sr 1st CL Slow Comb Op & Sr 1st CL Carrier II Op Jr Sr 1st CL Carrier Jr & Sr 1st CL Class D Speed Open 1st CL Class C Speed Jr & Sr 1st CLCIassB Speed Op & Sr 1st CL Cl Speed Op Sr Jr 1st CL Formula 40 Open 1st CL Class B Proto Jr 1st FF Class B Open 1st FF Class C Open HIGH PERFORMANCE * COMPETITION PROVEN * THIN RIGID BLADES O HARD MAPLE WOOD * SUPERBLY FINISHED COMPlEtELY FUEL PIOOF SPECIAL PRO SERIES 2 FOR RC-FREE FLIGHT CONTROL LINE DIAPITCHPRICE 5%3469 63489 73344tie 83%4 56129 94566% 77%139 10467149 106W 8W149 106EV4159 114677% 7%7%6159 116EW169 11%67169 126179 125W179 1356219 1456249 1556309 164%6389 VII VVIDE BLADE EW EXTRA WIDE SERIES 400 B FOR SPEEDS RACING ADVANCED DESIGN NO 1 IN PYLON RACING LEADING SPEED RECORD HOLDER OP ALL TIMES RC PYLON RACING DIA PITCH PRICE 5%3%4119 7 55%6 129 7 SN 5%N 65129 8% 6%6%7 7/,7%169 9 647 7%7%169 CONTROL LINE SPEEDS RACING DIA PITCH PRICE 4%6%7119 4%55%119 6 788%129 7 7% 10% 11139 8 69149 89N9%N149 8% 77%149 9 12 13199 N NARROW June 1977 57 OUT-PERFORMS ALL OTHERS AT THE 1976 NATIONALS