LAST MONTH included drawings calcula tions locate proper center-ofgravity airplane reason wrote proper because various proper centers-of-gravity example some centers-of-gravity far forward airplane will vety stable pitch fact airplane can made stable would very difficult maneuver other hand some centers-ofgravity far aft airplane would extremely maneuverable Depending what desired range proper centersof-gravity very broad use proper intended yield safe starting point test fly airplane After initial flights center-of-gravity can moved forward achieve pitch stability aft get ma neuverability Several people wrote ask what difference between center-of-mass center-ofgravity since tend alternate use out going long-winded discourse Ill say same far concerned Part occupational background involved working flight mechanics space vehi cles no such thing center-ofgravity vehicle deep space center-of-mass its same point whether vehicle space vicinity Earth So thats dont worry about has introduction what promised last month namely locate proper center-of-gravity canard aircraft flying-wing aircraft Please refer last column wont have redo drawings trying find proper center-ofgravity canard aircraft real differ ence tail front wing can use same equations before calculate wing tail areas well locations aerodynamic centers wing tail However calculate location proper center-of-gravity must change sign L term Equation 3 because tail front wing multiply term two Equation 3 July 88 column result will Equation 4 4 CG ab Area 3 x Wing Area R2 P 15R 4Since both terms equations nega tive proper center-of-gravity location front wing aerodynamic center amount calculated reason multiplying two wing causes effect tail conventional tail-last airplane present canard airplane unless tail very large relative wing might have already figured out flying-wing airplanes proper center-of-gravity would easier calculate other types airplane Since tail present have eliminate term involving tail length area result Equation 5 5 CG RT dfl5 15R before remaining term negative proper center-of-gravity location front wing aerodynamic center Last weekend attended Fiesta Five Flags contest Pensacola FL Dont ask did airplane docsnt fly well unless en gine works engine quit four five flights During flight kept running concerned would quit forgot fly airplane judge said Hey what kind engine want make sure dont buy So might think contest waste time because got great idea contestants talking Rick Sunderland Tallahas see FL about problem suggested car rying high idle maneuver en gine quitting Figure-M rolls agreed worth trying told achieve easily flip switch think idea worth sharing Futaba PCM owners because specifically cov ered radio inatruction manual pitch-control Mix switch Switch 11 right side top transmitter turns channel-3-to-8 mix must enable moving 3-8 mix-actuate switch inside back transmitter turn pitch-control Mix switch permits set en gine idle speed cutoff very fast mov ing Idle-Up lever top left side transmitter can adjust high-idle setting before takeoff turn pitch-control Mix switch Off after takeoff can raise gear turn high-idle tripping respec Mark Grubbs Taylors SC likes high-performance airplanes Aerobat 1 own design powered OS 40 yR MACS pipe Miss Martha R scratch-built uses Rossi 40 power features aileron air brakes driven mixing via its PCM radio control throt tle Mark claims itll go out sight vertical climb Both fun-fly airplanes Photos Mark Grubbs 50 Model Aviation Radio Conoi Sport Aerobatics Ron Van Putte III Sleepy Oaks Rd Ft Walton Beach FL 32548 Does Pattern plane look familiar No its Atlanta Omega Bob Smiths Patriciaa design several years ago Striking resemblance no Brad Lang Warner Rob ins GA sent picture old-tech still competitive airplane tive switches flight over put gear down turn off high-idle reversing two switches reason suggest operating both switches same time act memory aid turn On/Off high-idle since rarely forget raise lower landing gear Thanks Rick Sunderland discovered trick received very nice complimentary letter Larry Miles Independence MO al lowed Control Line flier never flown RC airplane much desire Nevertheless said read col umn humor eing creasing age seem have more appre ciation lighter side life suspect its inclusion comic cherish Hes right about inclusion humor Its much intentionai isis example outlook life hope people read column understand appreciate humor thats part Larry went muse about reason success Duke Foxs efforts noise reduction using plastic fuel tank after-muffler suspects what Duke ne ad dition providing additional surfaces sound waves bounce off provide soft sound-absorbing surface plastic tank various molecules give vibrationai energy much same way interiors high fi delity enclosures lined similar materials same goes automotive glass-pak muf flers perhaps small arms mufflers silencers deaden sounds Consequently Larry believes del engine muffler interior coated some high-temperature silicone glues might good starting point making effective single-unit muffler need plastic tank after-muffler Maybe has point Ive heard about others have tried similar things Perry Rose 51 Plainfield Road Moosup CT 06354 wrote tell aying kinds sound-reduction ideas lately read some place wrapping tuned pipe will deaden sharp tinny sound coming stumbled tubing Radio Shack sound meter checked theory OS 61 FSR ABC turn ing Rev-Up 11 x 8 12700 rpm put out 97-98 dRA 10 ft installed 11 x 9 Zinger stretched out pipe couple inches got 11500 rpm 94 dBA put rubber sleeve looks suspi ciously like piece bicycle inner tubeR VP MACS pipe repeated experiment 11 x 8 turned faster maybe due needle ad justing 12900 rpm 96-97 dBA 11 x 9 turned 11500 rpm put Out 92-93 dBA whole deal took half hour pipe underwing exposed rubber didnt bum melt during test Perry went describe got tub ing pipe putting Vaseline pipe working tubing pipe front end until covered whole pipe claimed took solid five minutes work get interested Perry will send sleeves $350 S&H included Bill Hintz 711 E Northridge Aye Glendora CA 91740 wrote asking knew plans Smog Hog Astro Hog Rudder Bug available couldnt come up source can please drop line Bill Note Sig released newly engineered kit Astro Hog recently RMcM Plug Wings rglass Belly Pan Pro-Cut Moies Wing Joiner Tubes Uitraligbt Honeycomb Wingcores extra $35 Optlonai PlastIc Fiberglass Canopy Fiberglass Fuselage molded wing Joiner tube August 1988 51 High Performance Models presents ECLIPSE Designed Henry Piorun Farmer Canadian National Champion & FAI Canadian Team Member IDesigned Specifically FAI Pattern Flying Perform Equally Well Other AMA Classes Basic Kit- $12500 Pre-Built Kit $32500 add $1500 S H Send Check Money Order HIGH PERFORMANCE MODELS 9556116 St North Delta British Columbia 6Z4 Canada 604-588-0605
Edition: Model Aviation - 1988/08
Page Numbers: 50, 51
LAST MONTH included drawings calcula tions locate proper center-ofgravity airplane reason wrote proper because various proper centers-of-gravity example some centers-of-gravity far forward airplane will vety stable pitch fact airplane can made stable would very difficult maneuver other hand some centers-ofgravity far aft airplane would extremely maneuverable Depending what desired range proper centersof-gravity very broad use proper intended yield safe starting point test fly airplane After initial flights center-of-gravity can moved forward achieve pitch stability aft get ma neuverability Several people wrote ask what difference between center-of-mass center-ofgravity since tend alternate use out going long-winded discourse Ill say same far concerned Part occupational background involved working flight mechanics space vehi cles no such thing center-ofgravity vehicle deep space center-of-mass its same point whether vehicle space vicinity Earth So thats dont worry about has introduction what promised last month namely locate proper center-of-gravity canard aircraft flying-wing aircraft Please refer last column wont have redo drawings trying find proper center-ofgravity canard aircraft real differ ence tail front wing can use same equations before calculate wing tail areas well locations aerodynamic centers wing tail However calculate location proper center-of-gravity must change sign L term Equation 3 because tail front wing multiply term two Equation 3 July 88 column result will Equation 4 4 CG ab Area 3 x Wing Area R2 P 15R 4Since both terms equations nega tive proper center-of-gravity location front wing aerodynamic center amount calculated reason multiplying two wing causes effect tail conventional tail-last airplane present canard airplane unless tail very large relative wing might have already figured out flying-wing airplanes proper center-of-gravity would easier calculate other types airplane Since tail present have eliminate term involving tail length area result Equation 5 5 CG RT dfl5 15R before remaining term negative proper center-of-gravity location front wing aerodynamic center Last weekend attended Fiesta Five Flags contest Pensacola FL Dont ask did airplane docsnt fly well unless en gine works engine quit four five flights During flight kept running concerned would quit forgot fly airplane judge said Hey what kind engine want make sure dont buy So might think contest waste time because got great idea contestants talking Rick Sunderland Tallahas see FL about problem suggested car rying high idle maneuver en gine quitting Figure-M rolls agreed worth trying told achieve easily flip switch think idea worth sharing Futaba PCM owners because specifically cov ered radio inatruction manual pitch-control Mix switch Switch 11 right side top transmitter turns channel-3-to-8 mix must enable moving 3-8 mix-actuate switch inside back transmitter turn pitch-control Mix switch permits set en gine idle speed cutoff very fast mov ing Idle-Up lever top left side transmitter can adjust high-idle setting before takeoff turn pitch-control Mix switch Off after takeoff can raise gear turn high-idle tripping respec Mark Grubbs Taylors SC likes high-performance airplanes Aerobat 1 own design powered OS 40 yR MACS pipe Miss Martha R scratch-built uses Rossi 40 power features aileron air brakes driven mixing via its PCM radio control throt tle Mark claims itll go out sight vertical climb Both fun-fly airplanes Photos Mark Grubbs 50 Model Aviation Radio Conoi Sport Aerobatics Ron Van Putte III Sleepy Oaks Rd Ft Walton Beach FL 32548 Does Pattern plane look familiar No its Atlanta Omega Bob Smiths Patriciaa design several years ago Striking resemblance no Brad Lang Warner Rob ins GA sent picture old-tech still competitive airplane tive switches flight over put gear down turn off high-idle reversing two switches reason suggest operating both switches same time act memory aid turn On/Off high-idle since rarely forget raise lower landing gear Thanks Rick Sunderland discovered trick received very nice complimentary letter Larry Miles Independence MO al lowed Control Line flier never flown RC airplane much desire Nevertheless said read col umn humor eing creasing age seem have more appre ciation lighter side life suspect its inclusion comic cherish Hes right about inclusion humor Its much intentionai isis example outlook life hope people read column understand appreciate humor thats part Larry went muse about reason success Duke Foxs efforts noise reduction using plastic fuel tank after-muffler suspects what Duke ne ad dition providing additional surfaces sound waves bounce off provide soft sound-absorbing surface plastic tank various molecules give vibrationai energy much same way interiors high fi delity enclosures lined similar materials same goes automotive glass-pak muf flers perhaps small arms mufflers silencers deaden sounds Consequently Larry believes del engine muffler interior coated some high-temperature silicone glues might good starting point making effective single-unit muffler need plastic tank after-muffler Maybe has point Ive heard about others have tried similar things Perry Rose 51 Plainfield Road Moosup CT 06354 wrote tell aying kinds sound-reduction ideas lately read some place wrapping tuned pipe will deaden sharp tinny sound coming stumbled tubing Radio Shack sound meter checked theory OS 61 FSR ABC turn ing Rev-Up 11 x 8 12700 rpm put out 97-98 dRA 10 ft installed 11 x 9 Zinger stretched out pipe couple inches got 11500 rpm 94 dBA put rubber sleeve looks suspi ciously like piece bicycle inner tubeR VP MACS pipe repeated experiment 11 x 8 turned faster maybe due needle ad justing 12900 rpm 96-97 dBA 11 x 9 turned 11500 rpm put Out 92-93 dBA whole deal took half hour pipe underwing exposed rubber didnt bum melt during test Perry went describe got tub ing pipe putting Vaseline pipe working tubing pipe front end until covered whole pipe claimed took solid five minutes work get interested Perry will send sleeves $350 S&H included Bill Hintz 711 E Northridge Aye Glendora CA 91740 wrote asking knew plans Smog Hog Astro Hog Rudder Bug available couldnt come up source can please drop line Bill Note Sig released newly engineered kit Astro Hog recently RMcM Plug Wings rglass Belly Pan Pro-Cut Moies Wing Joiner Tubes Uitraligbt Honeycomb Wingcores extra $35 Optlonai PlastIc Fiberglass Canopy Fiberglass Fuselage molded wing Joiner tube August 1988 51 High Performance Models presents ECLIPSE Designed Henry Piorun Farmer Canadian National Champion & FAI Canadian Team Member IDesigned Specifically FAI Pattern Flying Perform Equally Well Other AMA Classes Basic Kit- $12500 Pre-Built Kit $32500 add $1500 S H Send Check Money Order HIGH PERFORMANCE MODELS 9556116 St North Delta British Columbia 6Z4 Canada 604-588-0605