ne aunor nas nao mucn nanas-on experience wiin moaci canaras ne KflOW5 wnere OT ne speaks HI-Tech 2002 whIch has appearance Star Wars fighter 21st-century interceptor incorporates thrust-vectoring vane centered ducted-fan outlet TAIL-FIRST aircraft have intrigued minds men since Orville Wilbur pushed unstable canard Wright Flyer air Kitty Hawk Yes aircraft flew day terribly aft heavy Orville gone much higher did day probably would have done considerable damage himself craft What desperately needed thing called stability harder find canard-type aircraft answer will have come understanding con ventional aft-tail-configured aircraft Webster defines stability property body causes disturbed condition equilibrium steady motion develop forces moments restore original condition define sta bility pertains model alrcraft TAIL LIFT ability model correct its flight path after becoming upset gust pilot input Anyone has first flight new aft-tail aircraft found little sen sitive elevator has probably already flown unstable marginally-stable air craft Did land incident answered yes model probably marginally stable Did put six feet under yes model un stable out end arti cle will try simply describe stability differs canard aircraft conventional aft-tail aircraft will also refer negative stability NEGS unsta ble positive stability P05 stable neutral stability NUS Analogies will help understand three types stabilities go like golf-ball-sized steel ball center small slightly bowl-shaped table made soft clay going roll its own However tip table far enough will roll leave slight depression clay allowing return center table along path little effort analogous aircraft having POS softer clay POS father forward center gravity CG aircraft the POS Next imagine same ball flat glass-top table Although may roll right away will take slightest 52 Model Aviation breeze push set rolling also leaves no trail return may continue roll around till finds its way edge world analogous NUS real careful continued input angle table could keep ball near very center table much movement would case aircraft reach ing its aft-most CU position what some times have fuel tank nearly empty Finally imagine same ball same glass table outside gale-force windy day sensitive hands world arent going keep ball table never mind near center NEGS complete lack Full-scale model aircraft have three axes stability longitudinal elevator up sets stability lateral aileron upsets stability directional rudder up sets stability article will deal longitudinal stability control pertains canard aircraft Longitudinal stability aft-tail air craft dependent primarily upon CU posi tion and/or tail size build kit air planes build per plans oaly way can effect stability change move CU flew new model found floundering around sky its tail low probably surmised tail heavy moving CU forward things probably got better mov ing CU forward did seem help horizontal tail might too small en larging tail corrected problem have successfully beaten stability game putting pencil paper Canard airplanes obey same laws physics aft-tail aircraft However fine tuning kit canard scratch-built can lead some exciting gyrations sky Let explain First study Fig 1 As can see aft-tail aircraft gains its stability down loading tail force exerted tail constantly trying hold nose up force removed accidentally purpose nose drops prevents wing stall ing excessive angle attack reached tail begins produce up load bringing aircraft back horizon tal position reverse true nose aircraft gets too low tail creases its down load returning aircraft level Lets now move subject ques tion does canard-type aircraft get its stability Study Fig 2 canard-type aircraft can have herent built stability canard sur face made stall before main wing Loss lift canard surface allows nose drop preventing main wing stalls possibly spins just used word herent describing type stabil ity because todays super planeslike X-29athere artificial type sta bility gained use computers keep aircraft out trouble Lets assume have built yourself canard airplane took out fly first time finding very sensitive elevator input So moved CU forward tad found although airplane flew well going fast couldnt hold nose up high enough land slowly s too big decided would make canard elevator slightly larger produce lift turn tighter went out fly fix found out model wing heavy again So moved CU ward again calm airplane down loops got awful big again Feel like youre July 1988 53 Hi-Tech 2002 rotated tail-strike position Power OS Max 46 VR DF engine Kress RK-740 fan unit Design featured September 1986 MA full-size plan No 525 chasing tail Well literally Increasing canard size chang ing CO reduced stability creased control power same time making airplane unmanageable again some canard designs happy balance tween aerobatic performance good posi tive stability can achieved CO posi CT IONtion alone everything have done still does net performance wish go back aft-tail aircraft Really Im kidding Now have better understanding stability lets talk about control Control ling pitch axis canard-type air craft foreplane called canard planform shape although some impor tance stability control will IONissue method producing pitch-up pitch-down moments / IFigure 3 depicts four common methods producing pitching moment all-flying canard simple flapped ca ___________nard fixed canard both leading ___________trailing edge flaps all-flying canard leading edge device all-flying canard although simple construction no separate pieces addi tional moving parts prone damage hard nose-down landing cause supported single usu ally flimsy shaft However configura tion best producing large pitching moments tighter turns fixed canard trailing edge ele vator although common kits scratch builders worst four producing large pitching moments highly-loaded canard stability discussed earlier stalls easily high flap elevator deflections way get around premature stall problem modify canard next type third choice Fig 3 fixed ca nard flap leading edge device droop droop leading edge postContinued page 56 54 Model Aviation decorated model Hi-Tech 2000 plainer atop rocks Hi-Tech 2001 Design both nearly same though structures different H-T 2001 abandoned fiberglass fuselage H-T 2000 among other things came out about pound lighter heavier plane dog flight H-T 2001 flew sprightly its OS 25 VF DF engine RK-20 fan unit Hi-Tech 2001 available MA full-size plan number 456 TWO CYCLE AND DRILLED AND TSPPID TWO CYCLE ENGINE MOUNTS JE40ENYA 405S-45C1 4W40FOX 40 86 DELUXE JTKB2OK&BRtCSportster JT-kB45K & B RIG Spoflstar JT-KB6OK & B RIG Sporasoar JT4WOAIINE 20-25 RIG JT-lii30IRVINE 3040 RIG J11V61IRViNE 61 RIG J442OMAX 20-25 FP J1M25MAX 25 TSR JFM35MAX 35-40 PP JT-M40MAX 40 TSR JTh446MAX 405F-405F j1M50MAX50FSR JTM61MAX61ISRO1SF JtMIO6MAX 91-100 TSR JT-821SFIRAT 2125-29 JT-5T40Sr-COMO 4045-46 JT-5T51STG0M0 5100 JT-S1U1SIGOMO 61-75-90 JT-S13000 ST 2000-2500-3090 PYWAI RAGING M0UNS iTISPY 15 dIp 800 Jr-A WY 40 d0- 800 1000 JT42 1000 JT-40 800 JT-84 1000 JT-121 sinJT41 800 JT-49 500 JF2O 100 JM 800 JT-48 800 Jr-81 1000 JT-82 1000 JT122 1000 JT-43 100Jr-AS sinJ65 IBMJT123 800 1000 12WJ120 isinJr-AC 2500JT-80 JF120 FOUR CYCLE ENGINE MOUNTS DRILLED AND lAPPED FOUR CYCLE ENGINE MOUNTS ENYS 35-40 401000 ENYA 46 AG1000 ENYS 60-80-90-120 401300 ENVA R 120402000 HPVT211000 HPVT491300 MAXFS20800 MAX FS 40-40 Surpass1000 MAX FS48Suss1000 1100 MAX FS 60-75-901100 MAX 120-120 Surpass 2000 SAflOFA3O1000 SAnD F40-4S 1000 SAflDMi65 SArFOFA12O2000 mu Mirage 10-25 dls 800 Mirage 20-45 dia 800 Merage 50-80 diap 1100 Mirage 90-120 dIs 1800 FREE CATALOG cultpeCIt0tons 1It iVeeKS S US 01 WiO ourp8T e BS sA611 5tandOSeO055ti Ce1ed tb phli 91og %AS 68geB loclades HY-70B Motor 8-62 Battery 2 Props Charge Plug Coooector Accessory Pkg screws spacers etc VL-111BR$2795 Same VI-iliB bat HY-7OBR Mator Remote Flight Battery Holder MINI POWER AT ITS BEST t Weight l P-30 Size Models k Cl 7-1 Gear Ratio t ant Start Cost Battery Power ner FLIGHT BATTERIE HY-70B$1495 B-62 2uSD mAHr 9 gina Ao impruoed HY-70 Features reioforcedSoap ioto place motor prop shaft oeopreoe sleese eogageNo wiriog reouiredl diseogage Fae-wheeliog8-52 2u80 mAHr 13 gins .5 HY-7OBR$1795 Same B-62 motor-rue Same HY-70B equipped Remote 1 mioutes Flight Battery Holder er has 7 8-63 3a50 mAHr 13g... $13 5 irwl niiiel t1icnnnpcts Slide battery sowerful shorter motor-rue pones canard stall considerably ever said before little tricks canard will still stall before main wing because its relatively small size compared wing last alternative powerful pitch con trol solely canard all-flying canard leading edge device combination gives best pitch control very high deflections methods have draw backs whether structural aero dynamic choice use de pends highly overall configuration aircraft involved preference hap pens #3 Fig 3 because offers ex ceptional pitch control coupled good structural integrity due non-moving center section box aircraft designers call last subject would like touch upon thrust vectoring act using high energy air produced propel ler fan complementing canard pitch control small vane supported hind prop fan directly engine centerline vane mechanically coupled canard produce common up commands ie canard de vices commands up trailing edge vane moves up Any have flown close-coupled Control Line Com bat ships probably have some experi ence effect Combat en gine quits ship comes down hurry applying elevator input cant keep nose up airplane slows down Thrust vectoring some canard aircraft can mean saving ship has found its way phenomenon known deep stall Deep stall canard aircraft often fatal like dreaded flat spin con ventional aft-tail aircraft big differ ence deep stall aircraft rarely spins motion like maple leaf falling its branch high atop tree aircraft falls very slowly becomes uncontrollable aircraft literally falls straight ground upright inverted wings level no airflow over canard provide pitch control thrust vectoring nothing behind propel ler fan produce moment recover deep stall Thrust vectoring can thought complement canard pitch control aircraft saver should find canard airplane deep stall phenomenon Canard airplanes properly designed can just easy much fun fly afttail aircraft providing follow some basic rules Rule #1 Keep canard airfoil thick leading edge blunt prevent stalling too soon though have al ready made point canard has stall before wing order have POS Continued page 145 56 Model Aviation fully normal Pro-head flybarless system will have make ex cuses should consider what said pre view Legend some details may change before production begins However flew three prototypes am very impressed machines perform ance flexibility As expected come stock kit Legend nine-pound 60-class belt-driven tail flybarless rotor aerobatic rocket ship cause commonalties other GMP ma chines could add other GMP heads 1 1/2-in-longer belt-drive tail stan dard GMP shaft-drive tail could up date Competitor Cobra already own can literally style Legend suit current desires aerobatics Scale FAI competition Pick tail head suit task GMP also working new rotor head us ing proven dampening systembut mid-position underslung flybar way John Gorham works wont take long him fin ish Legend package various acces sories dedicated GMP expects early sum mer release sounds realistic Stay touch GMP dealer further updates So whats new department have apologize readers manufacturers have sent letters and/or products testing have extremely busy last six monthsboth daytime job McDonnell Douglas LIMP am process finishing third three consecutive movies last few months Ive built three fuselage plugs seven Helicoptersnone personal machines though Im doing lot flying havent done Please patient can see day light again really have urge finish up current projects some serious fun fly ing Now spring turning summer Ill bet lot afternoon-evening sport flying go ing over country Boy sure look ward joining fun BCNU Larry Canard Stability/Hunt Continued page 56 No matter what little tricks have preventing canard stalling will always stall before wing because its much smaller size air likes big surfaces run over better small onesReynolds effect Rule #2 Larger elevators canard small deflections better small elevators large deflections probably know also works eleva tors aft-tail aircraft control sur face model airplane Rule #3 Wings should have blunt leading edges and/or sufficient twist washout prevent tips stalling Rule #4 canard large span may wish washout canard tips well wing tips help prevent pre mature stall Rule #5 Get used idea flying airplane looks like its going reverse 100 mph biggest complaints airplane educated spectators can never tell way airplane going Perception problems will crash airplane faster design flaws Rule #6 Seal control surface gaps canard increase effectiveness Suggestion #1 using fixed ca nard trailing edge elevator consider using leading edge droop device pre vent premature canard stall see Fig 4 Suggestion #2 after fussing fighting canard design youre happy stability level still cant get turn tight loop small enough give some thought using thrust vectoring assist canard pitch con trol see Fig 5 very few canard kits mar ket choose event youd like run out buy avail able unfortunately have no personal expe rience have refining jet-look canardtype aircraft better six years have much success fly very well can made very stable modified easily very aerobatic stronghearted pilot short discussion hope have given awareness some com plexities involved making canard air plane flyand intrigued enough will investigate Wonderful World Backwards Flight [When responding advertisers mention read about ModelAviation ment first thing apparent No maxed out Korda places sixth Robert Copland Eng land wins nine three-minute maxes made during entire contest assume Category III rules twominute maxes situation changes little Copland still wins max-out Korda fifth oniy 21 maxes made Zaic flying proxy Vincre France fails tie Copland second Now mean no disrespect Mr Korda other participant contest believe present Old-Timer Rubber fliers flying under current rules would score maxes did 1939 using same designs Ev idence such rash statement will found report 1986 SAM Society Antique ModelersEd Champs appeared October 1986 issue magazine meet Rubber Cabin flown two-minute maxes maxing out being allowed flyoff flight Five maxed out using OldTimer Wakefields three being 1939 Kordas 1936 design weather super-good day either would like share thoughts just fliers today get higher performance worlds best did 1939 designs have changed enforce weight rule judgement few underweight models result think fact total weight of todays Old-Timer Rubber models much different byContinued page 149 July1988 145 FF Old-Timers/Baker Continued page 57
Edition: Model Aviation - 1988/07
Page Numbers: 52, 53, 54, 56, 145
ne aunor nas nao mucn nanas-on experience wiin moaci canaras ne KflOW5 wnere OT ne speaks HI-Tech 2002 whIch has appearance Star Wars fighter 21st-century interceptor incorporates thrust-vectoring vane centered ducted-fan outlet TAIL-FIRST aircraft have intrigued minds men since Orville Wilbur pushed unstable canard Wright Flyer air Kitty Hawk Yes aircraft flew day terribly aft heavy Orville gone much higher did day probably would have done considerable damage himself craft What desperately needed thing called stability harder find canard-type aircraft answer will have come understanding con ventional aft-tail-configured aircraft Webster defines stability property body causes disturbed condition equilibrium steady motion develop forces moments restore original condition define sta bility pertains model alrcraft TAIL LIFT ability model correct its flight path after becoming upset gust pilot input Anyone has first flight new aft-tail aircraft found little sen sitive elevator has probably already flown unstable marginally-stable air craft Did land incident answered yes model probably marginally stable Did put six feet under yes model un stable out end arti cle will try simply describe stability differs canard aircraft conventional aft-tail aircraft will also refer negative stability NEGS unsta ble positive stability P05 stable neutral stability NUS Analogies will help understand three types stabilities go like golf-ball-sized steel ball center small slightly bowl-shaped table made soft clay going roll its own However tip table far enough will roll leave slight depression clay allowing return center table along path little effort analogous aircraft having POS softer clay POS father forward center gravity CG aircraft the POS Next imagine same ball flat glass-top table Although may roll right away will take slightest 52 Model Aviation breeze push set rolling also leaves no trail return may continue roll around till finds its way edge world analogous NUS real careful continued input angle table could keep ball near very center table much movement would case aircraft reach ing its aft-most CU position what some times have fuel tank nearly empty Finally imagine same ball same glass table outside gale-force windy day sensitive hands world arent going keep ball table never mind near center NEGS complete lack Full-scale model aircraft have three axes stability longitudinal elevator up sets stability lateral aileron upsets stability directional rudder up sets stability article will deal longitudinal stability control pertains canard aircraft Longitudinal stability aft-tail air craft dependent primarily upon CU posi tion and/or tail size build kit air planes build per plans oaly way can effect stability change move CU flew new model found floundering around sky its tail low probably surmised tail heavy moving CU forward things probably got better mov ing CU forward did seem help horizontal tail might too small en larging tail corrected problem have successfully beaten stability game putting pencil paper Canard airplanes obey same laws physics aft-tail aircraft However fine tuning kit canard scratch-built can lead some exciting gyrations sky Let explain First study Fig 1 As can see aft-tail aircraft gains its stability down loading tail force exerted tail constantly trying hold nose up force removed accidentally purpose nose drops prevents wing stall ing excessive angle attack reached tail begins produce up load bringing aircraft back horizon tal position reverse true nose aircraft gets too low tail creases its down load returning aircraft level Lets now move subject ques tion does canard-type aircraft get its stability Study Fig 2 canard-type aircraft can have herent built stability canard sur face made stall before main wing Loss lift canard surface allows nose drop preventing main wing stalls possibly spins just used word herent describing type stabil ity because todays super planeslike X-29athere artificial type sta bility gained use computers keep aircraft out trouble Lets assume have built yourself canard airplane took out fly first time finding very sensitive elevator input So moved CU forward tad found although airplane flew well going fast couldnt hold nose up high enough land slowly s too big decided would make canard elevator slightly larger produce lift turn tighter went out fly fix found out model wing heavy again So moved CU ward again calm airplane down loops got awful big again Feel like youre July 1988 53 Hi-Tech 2002 rotated tail-strike position Power OS Max 46 VR DF engine Kress RK-740 fan unit Design featured September 1986 MA full-size plan No 525 chasing tail Well literally Increasing canard size chang ing CO reduced stability creased control power same time making airplane unmanageable again some canard designs happy balance tween aerobatic performance good posi tive stability can achieved CO posi CT IONtion alone everything have done still does net performance wish go back aft-tail aircraft Really Im kidding Now have better understanding stability lets talk about control Control ling pitch axis canard-type air craft foreplane called canard planform shape although some impor tance stability control will IONissue method producing pitch-up pitch-down moments / IFigure 3 depicts four common methods producing pitching moment all-flying canard simple flapped ca ___________nard fixed canard both leading ___________trailing edge flaps all-flying canard leading edge device all-flying canard although simple construction no separate pieces addi tional moving parts prone damage hard nose-down landing cause supported single usu ally flimsy shaft However configura tion best producing large pitching moments tighter turns fixed canard trailing edge ele vator although common kits scratch builders worst four producing large pitching moments highly-loaded canard stability discussed earlier stalls easily high flap elevator deflections way get around premature stall problem modify canard next type third choice Fig 3 fixed ca nard flap leading edge device droop droop leading edge postContinued page 56 54 Model Aviation decorated model Hi-Tech 2000 plainer atop rocks Hi-Tech 2001 Design both nearly same though structures different H-T 2001 abandoned fiberglass fuselage H-T 2000 among other things came out about pound lighter heavier plane dog flight H-T 2001 flew sprightly its OS 25 VF DF engine RK-20 fan unit Hi-Tech 2001 available MA full-size plan number 456 TWO CYCLE AND DRILLED AND TSPPID TWO CYCLE ENGINE MOUNTS JE40ENYA 405S-45C1 4W40FOX 40 86 DELUXE JTKB2OK&BRtCSportster JT-kB45K & B RIG Spoflstar JT-KB6OK & B RIG Sporasoar JT4WOAIINE 20-25 RIG JT-lii30IRVINE 3040 RIG J11V61IRViNE 61 RIG J442OMAX 20-25 FP J1M25MAX 25 TSR JFM35MAX 35-40 PP JT-M40MAX 40 TSR JTh446MAX 405F-405F j1M50MAX50FSR JTM61MAX61ISRO1SF JtMIO6MAX 91-100 TSR JT-821SFIRAT 2125-29 JT-5T40Sr-COMO 4045-46 JT-5T51STG0M0 5100 JT-S1U1SIGOMO 61-75-90 JT-S13000 ST 2000-2500-3090 PYWAI RAGING M0UNS iTISPY 15 dIp 800 Jr-A WY 40 d0- 800 1000 JT42 1000 JT-40 800 JT-84 1000 JT-121 sinJT41 800 JT-49 500 JF2O 100 JM 800 JT-48 800 Jr-81 1000 JT-82 1000 JT122 1000 JT-43 100Jr-AS sinJ65 IBMJT123 800 1000 12WJ120 isinJr-AC 2500JT-80 JF120 FOUR CYCLE ENGINE MOUNTS DRILLED AND lAPPED FOUR CYCLE ENGINE MOUNTS ENYS 35-40 401000 ENYA 46 AG1000 ENYS 60-80-90-120 401300 ENVA R 120402000 HPVT211000 HPVT491300 MAXFS20800 MAX FS 40-40 Surpass1000 MAX FS48Suss1000 1100 MAX FS 60-75-901100 MAX 120-120 Surpass 2000 SAflOFA3O1000 SAnD F40-4S 1000 SAflDMi65 SArFOFA12O2000 mu Mirage 10-25 dls 800 Mirage 20-45 dia 800 Merage 50-80 diap 1100 Mirage 90-120 dIs 1800 FREE CATALOG cultpeCIt0tons 1It iVeeKS S US 01 WiO ourp8T e BS sA611 5tandOSeO055ti Ce1ed tb phli 91og %AS 68geB loclades HY-70B Motor 8-62 Battery 2 Props Charge Plug Coooector Accessory Pkg screws spacers etc VL-111BR$2795 Same VI-iliB bat HY-7OBR Mator Remote Flight Battery Holder MINI POWER AT ITS BEST t Weight l P-30 Size Models k Cl 7-1 Gear Ratio t ant Start Cost Battery Power ner FLIGHT BATTERIE HY-70B$1495 B-62 2uSD mAHr 9 gina Ao impruoed HY-70 Features reioforcedSoap ioto place motor prop shaft oeopreoe sleese eogageNo wiriog reouiredl diseogage Fae-wheeliog8-52 2u80 mAHr 13 gins .5 HY-7OBR$1795 Same B-62 motor-rue Same HY-70B equipped Remote 1 mioutes Flight Battery Holder er has 7 8-63 3a50 mAHr 13g... $13 5 irwl niiiel t1icnnnpcts Slide battery sowerful shorter motor-rue pones canard stall considerably ever said before little tricks canard will still stall before main wing because its relatively small size compared wing last alternative powerful pitch con trol solely canard all-flying canard leading edge device combination gives best pitch control very high deflections methods have draw backs whether structural aero dynamic choice use de pends highly overall configuration aircraft involved preference hap pens #3 Fig 3 because offers ex ceptional pitch control coupled good structural integrity due non-moving center section box aircraft designers call last subject would like touch upon thrust vectoring act using high energy air produced propel ler fan complementing canard pitch control small vane supported hind prop fan directly engine centerline vane mechanically coupled canard produce common up commands ie canard de vices commands up trailing edge vane moves up Any have flown close-coupled Control Line Com bat ships probably have some experi ence effect Combat en gine quits ship comes down hurry applying elevator input cant keep nose up airplane slows down Thrust vectoring some canard aircraft can mean saving ship has found its way phenomenon known deep stall Deep stall canard aircraft often fatal like dreaded flat spin con ventional aft-tail aircraft big differ ence deep stall aircraft rarely spins motion like maple leaf falling its branch high atop tree aircraft falls very slowly becomes uncontrollable aircraft literally falls straight ground upright inverted wings level no airflow over canard provide pitch control thrust vectoring nothing behind propel ler fan produce moment recover deep stall Thrust vectoring can thought complement canard pitch control aircraft saver should find canard airplane deep stall phenomenon Canard airplanes properly designed can just easy much fun fly afttail aircraft providing follow some basic rules Rule #1 Keep canard airfoil thick leading edge blunt prevent stalling too soon though have al ready made point canard has stall before wing order have POS Continued page 145 56 Model Aviation fully normal Pro-head flybarless system will have make ex cuses should consider what said pre view Legend some details may change before production begins However flew three prototypes am very impressed machines perform ance flexibility As expected come stock kit Legend nine-pound 60-class belt-driven tail flybarless rotor aerobatic rocket ship cause commonalties other GMP ma chines could add other GMP heads 1 1/2-in-longer belt-drive tail stan dard GMP shaft-drive tail could up date Competitor Cobra already own can literally style Legend suit current desires aerobatics Scale FAI competition Pick tail head suit task GMP also working new rotor head us ing proven dampening systembut mid-position underslung flybar way John Gorham works wont take long him fin ish Legend package various acces sories dedicated GMP expects early sum mer release sounds realistic Stay touch GMP dealer further updates So whats new department have apologize readers manufacturers have sent letters and/or products testing have extremely busy last six monthsboth daytime job McDonnell Douglas LIMP am process finishing third three consecutive movies last few months Ive built three fuselage plugs seven Helicoptersnone personal machines though Im doing lot flying havent done Please patient can see day light again really have urge finish up current projects some serious fun fly ing Now spring turning summer Ill bet lot afternoon-evening sport flying go ing over country Boy sure look ward joining fun BCNU Larry Canard Stability/Hunt Continued page 56 No matter what little tricks have preventing canard stalling will always stall before wing because its much smaller size air likes big surfaces run over better small onesReynolds effect Rule #2 Larger elevators canard small deflections better small elevators large deflections probably know also works eleva tors aft-tail aircraft control sur face model airplane Rule #3 Wings should have blunt leading edges and/or sufficient twist washout prevent tips stalling Rule #4 canard large span may wish washout canard tips well wing tips help prevent pre mature stall Rule #5 Get used idea flying airplane looks like its going reverse 100 mph biggest complaints airplane educated spectators can never tell way airplane going Perception problems will crash airplane faster design flaws Rule #6 Seal control surface gaps canard increase effectiveness Suggestion #1 using fixed ca nard trailing edge elevator consider using leading edge droop device pre vent premature canard stall see Fig 4 Suggestion #2 after fussing fighting canard design youre happy stability level still cant get turn tight loop small enough give some thought using thrust vectoring assist canard pitch con trol see Fig 5 very few canard kits mar ket choose event youd like run out buy avail able unfortunately have no personal expe rience have refining jet-look canardtype aircraft better six years have much success fly very well can made very stable modified easily very aerobatic stronghearted pilot short discussion hope have given awareness some com plexities involved making canard air plane flyand intrigued enough will investigate Wonderful World Backwards Flight [When responding advertisers mention read about ModelAviation ment first thing apparent No maxed out Korda places sixth Robert Copland Eng land wins nine three-minute maxes made during entire contest assume Category III rules twominute maxes situation changes little Copland still wins max-out Korda fifth oniy 21 maxes made Zaic flying proxy Vincre France fails tie Copland second Now mean no disrespect Mr Korda other participant contest believe present Old-Timer Rubber fliers flying under current rules would score maxes did 1939 using same designs Ev idence such rash statement will found report 1986 SAM Society Antique ModelersEd Champs appeared October 1986 issue magazine meet Rubber Cabin flown two-minute maxes maxing out being allowed flyoff flight Five maxed out using OldTimer Wakefields three being 1939 Kordas 1936 design weather super-good day either would like share thoughts just fliers today get higher performance worlds best did 1939 designs have changed enforce weight rule judgement few underweight models result think fact total weight of todays Old-Timer Rubber models much different byContinued page 149 July1988 145 FF Old-Timers/Baker Continued page 57
Edition: Model Aviation - 1988/07
Page Numbers: 52, 53, 54, 56, 145
ne aunor nas nao mucn nanas-on experience wiin moaci canaras ne KflOW5 wnere OT ne speaks HI-Tech 2002 whIch has appearance Star Wars fighter 21st-century interceptor incorporates thrust-vectoring vane centered ducted-fan outlet TAIL-FIRST aircraft have intrigued minds men since Orville Wilbur pushed unstable canard Wright Flyer air Kitty Hawk Yes aircraft flew day terribly aft heavy Orville gone much higher did day probably would have done considerable damage himself craft What desperately needed thing called stability harder find canard-type aircraft answer will have come understanding con ventional aft-tail-configured aircraft Webster defines stability property body causes disturbed condition equilibrium steady motion develop forces moments restore original condition define sta bility pertains model alrcraft TAIL LIFT ability model correct its flight path after becoming upset gust pilot input Anyone has first flight new aft-tail aircraft found little sen sitive elevator has probably already flown unstable marginally-stable air craft Did land incident answered yes model probably marginally stable Did put six feet under yes model un stable out end arti cle will try simply describe stability differs canard aircraft conventional aft-tail aircraft will also refer negative stability NEGS unsta ble positive stability P05 stable neutral stability NUS Analogies will help understand three types stabilities go like golf-ball-sized steel ball center small slightly bowl-shaped table made soft clay going roll its own However tip table far enough will roll leave slight depression clay allowing return center table along path little effort analogous aircraft having POS softer clay POS father forward center gravity CG aircraft the POS Next imagine same ball flat glass-top table Although may roll right away will take slightest 52 Model Aviation breeze push set rolling also leaves no trail return may continue roll around till finds its way edge world analogous NUS real careful continued input angle table could keep ball near very center table much movement would case aircraft reach ing its aft-most CU position what some times have fuel tank nearly empty Finally imagine same ball same glass table outside gale-force windy day sensitive hands world arent going keep ball table never mind near center NEGS complete lack Full-scale model aircraft have three axes stability longitudinal elevator up sets stability lateral aileron upsets stability directional rudder up sets stability article will deal longitudinal stability control pertains canard aircraft Longitudinal stability aft-tail air craft dependent primarily upon CU posi tion and/or tail size build kit air planes build per plans oaly way can effect stability change move CU flew new model found floundering around sky its tail low probably surmised tail heavy moving CU forward things probably got better mov ing CU forward did seem help horizontal tail might too small en larging tail corrected problem have successfully beaten stability game putting pencil paper Canard airplanes obey same laws physics aft-tail aircraft However fine tuning kit canard scratch-built can lead some exciting gyrations sky Let explain First study Fig 1 As can see aft-tail aircraft gains its stability down loading tail force exerted tail constantly trying hold nose up force removed accidentally purpose nose drops prevents wing stall ing excessive angle attack reached tail begins produce up load bringing aircraft back horizon tal position reverse true nose aircraft gets too low tail creases its down load returning aircraft level Lets now move subject ques tion does canard-type aircraft get its stability Study Fig 2 canard-type aircraft can have herent built stability canard sur face made stall before main wing Loss lift canard surface allows nose drop preventing main wing stalls possibly spins just used word herent describing type stabil ity because todays super planeslike X-29athere artificial type sta bility gained use computers keep aircraft out trouble Lets assume have built yourself canard airplane took out fly first time finding very sensitive elevator input So moved CU forward tad found although airplane flew well going fast couldnt hold nose up high enough land slowly s too big decided would make canard elevator slightly larger produce lift turn tighter went out fly fix found out model wing heavy again So moved CU ward again calm airplane down loops got awful big again Feel like youre July 1988 53 Hi-Tech 2002 rotated tail-strike position Power OS Max 46 VR DF engine Kress RK-740 fan unit Design featured September 1986 MA full-size plan No 525 chasing tail Well literally Increasing canard size chang ing CO reduced stability creased control power same time making airplane unmanageable again some canard designs happy balance tween aerobatic performance good posi tive stability can achieved CO posi CT IONtion alone everything have done still does net performance wish go back aft-tail aircraft Really Im kidding Now have better understanding stability lets talk about control Control ling pitch axis canard-type air craft foreplane called canard planform shape although some impor tance stability control will IONissue method producing pitch-up pitch-down moments / IFigure 3 depicts four common methods producing pitching moment all-flying canard simple flapped ca ___________nard fixed canard both leading ___________trailing edge flaps all-flying canard leading edge device all-flying canard although simple construction no separate pieces addi tional moving parts prone damage hard nose-down landing cause supported single usu ally flimsy shaft However configura tion best producing large pitching moments tighter turns fixed canard trailing edge ele vator although common kits scratch builders worst four producing large pitching moments highly-loaded canard stability discussed earlier stalls easily high flap elevator deflections way get around premature stall problem modify canard next type third choice Fig 3 fixed ca nard flap leading edge device droop droop leading edge postContinued page 56 54 Model Aviation decorated model Hi-Tech 2000 plainer atop rocks Hi-Tech 2001 Design both nearly same though structures different H-T 2001 abandoned fiberglass fuselage H-T 2000 among other things came out about pound lighter heavier plane dog flight H-T 2001 flew sprightly its OS 25 VF DF engine RK-20 fan unit Hi-Tech 2001 available MA full-size plan number 456 TWO CYCLE AND DRILLED AND TSPPID TWO CYCLE ENGINE MOUNTS JE40ENYA 405S-45C1 4W40FOX 40 86 DELUXE JTKB2OK&BRtCSportster JT-kB45K & B RIG Spoflstar JT-KB6OK & B RIG Sporasoar JT4WOAIINE 20-25 RIG JT-lii30IRVINE 3040 RIG J11V61IRViNE 61 RIG J442OMAX 20-25 FP J1M25MAX 25 TSR JFM35MAX 35-40 PP JT-M40MAX 40 TSR JTh446MAX 405F-405F j1M50MAX50FSR JTM61MAX61ISRO1SF JtMIO6MAX 91-100 TSR JT-821SFIRAT 2125-29 JT-5T40Sr-COMO 4045-46 JT-5T51STG0M0 5100 JT-S1U1SIGOMO 61-75-90 JT-S13000 ST 2000-2500-3090 PYWAI RAGING M0UNS iTISPY 15 dIp 800 Jr-A WY 40 d0- 800 1000 JT42 1000 JT-40 800 JT-84 1000 JT-121 sinJT41 800 JT-49 500 JF2O 100 JM 800 JT-48 800 Jr-81 1000 JT-82 1000 JT122 1000 JT-43 100Jr-AS sinJ65 IBMJT123 800 1000 12WJ120 isinJr-AC 2500JT-80 JF120 FOUR CYCLE ENGINE MOUNTS DRILLED AND lAPPED FOUR CYCLE ENGINE MOUNTS ENYS 35-40 401000 ENYA 46 AG1000 ENYS 60-80-90-120 401300 ENVA R 120402000 HPVT211000 HPVT491300 MAXFS20800 MAX FS 40-40 Surpass1000 MAX FS48Suss1000 1100 MAX FS 60-75-901100 MAX 120-120 Surpass 2000 SAflOFA3O1000 SAnD F40-4S 1000 SAflDMi65 SArFOFA12O2000 mu Mirage 10-25 dls 800 Mirage 20-45 dia 800 Merage 50-80 diap 1100 Mirage 90-120 dIs 1800 FREE CATALOG cultpeCIt0tons 1It iVeeKS S US 01 WiO ourp8T e BS sA611 5tandOSeO055ti Ce1ed tb phli 91og %AS 68geB loclades HY-70B Motor 8-62 Battery 2 Props Charge Plug Coooector Accessory Pkg screws spacers etc VL-111BR$2795 Same VI-iliB bat HY-7OBR Mator Remote Flight Battery Holder MINI POWER AT ITS BEST t Weight l P-30 Size Models k Cl 7-1 Gear Ratio t ant Start Cost Battery Power ner FLIGHT BATTERIE HY-70B$1495 B-62 2uSD mAHr 9 gina Ao impruoed HY-70 Features reioforcedSoap ioto place motor prop shaft oeopreoe sleese eogageNo wiriog reouiredl diseogage Fae-wheeliog8-52 2u80 mAHr 13 gins .5 HY-7OBR$1795 Same B-62 motor-rue Same HY-70B equipped Remote 1 mioutes Flight Battery Holder er has 7 8-63 3a50 mAHr 13g... $13 5 irwl niiiel t1icnnnpcts Slide battery sowerful shorter motor-rue pones canard stall considerably ever said before little tricks canard will still stall before main wing because its relatively small size compared wing last alternative powerful pitch con trol solely canard all-flying canard leading edge device combination gives best pitch control very high deflections methods have draw backs whether structural aero dynamic choice use de pends highly overall configuration aircraft involved preference hap pens #3 Fig 3 because offers ex ceptional pitch control coupled good structural integrity due non-moving center section box aircraft designers call last subject would like touch upon thrust vectoring act using high energy air produced propel ler fan complementing canard pitch control small vane supported hind prop fan directly engine centerline vane mechanically coupled canard produce common up commands ie canard de vices commands up trailing edge vane moves up Any have flown close-coupled Control Line Com bat ships probably have some experi ence effect Combat en gine quits ship comes down hurry applying elevator input cant keep nose up airplane slows down Thrust vectoring some canard aircraft can mean saving ship has found its way phenomenon known deep stall Deep stall canard aircraft often fatal like dreaded flat spin con ventional aft-tail aircraft big differ ence deep stall aircraft rarely spins motion like maple leaf falling its branch high atop tree aircraft falls very slowly becomes uncontrollable aircraft literally falls straight ground upright inverted wings level no airflow over canard provide pitch control thrust vectoring nothing behind propel ler fan produce moment recover deep stall Thrust vectoring can thought complement canard pitch control aircraft saver should find canard airplane deep stall phenomenon Canard airplanes properly designed can just easy much fun fly afttail aircraft providing follow some basic rules Rule #1 Keep canard airfoil thick leading edge blunt prevent stalling too soon though have al ready made point canard has stall before wing order have POS Continued page 145 56 Model Aviation fully normal Pro-head flybarless system will have make ex cuses should consider what said pre view Legend some details may change before production begins However flew three prototypes am very impressed machines perform ance flexibility As expected come stock kit Legend nine-pound 60-class belt-driven tail flybarless rotor aerobatic rocket ship cause commonalties other GMP ma chines could add other GMP heads 1 1/2-in-longer belt-drive tail stan dard GMP shaft-drive tail could up date Competitor Cobra already own can literally style Legend suit current desires aerobatics Scale FAI competition Pick tail head suit task GMP also working new rotor head us ing proven dampening systembut mid-position underslung flybar way John Gorham works wont take long him fin ish Legend package various acces sories dedicated GMP expects early sum mer release sounds realistic Stay touch GMP dealer further updates So whats new department have apologize readers manufacturers have sent letters and/or products testing have extremely busy last six monthsboth daytime job McDonnell Douglas LIMP am process finishing third three consecutive movies last few months Ive built three fuselage plugs seven Helicoptersnone personal machines though Im doing lot flying havent done Please patient can see day light again really have urge finish up current projects some serious fun fly ing Now spring turning summer Ill bet lot afternoon-evening sport flying go ing over country Boy sure look ward joining fun BCNU Larry Canard Stability/Hunt Continued page 56 No matter what little tricks have preventing canard stalling will always stall before wing because its much smaller size air likes big surfaces run over better small onesReynolds effect Rule #2 Larger elevators canard small deflections better small elevators large deflections probably know also works eleva tors aft-tail aircraft control sur face model airplane Rule #3 Wings should have blunt leading edges and/or sufficient twist washout prevent tips stalling Rule #4 canard large span may wish washout canard tips well wing tips help prevent pre mature stall Rule #5 Get used idea flying airplane looks like its going reverse 100 mph biggest complaints airplane educated spectators can never tell way airplane going Perception problems will crash airplane faster design flaws Rule #6 Seal control surface gaps canard increase effectiveness Suggestion #1 using fixed ca nard trailing edge elevator consider using leading edge droop device pre vent premature canard stall see Fig 4 Suggestion #2 after fussing fighting canard design youre happy stability level still cant get turn tight loop small enough give some thought using thrust vectoring assist canard pitch con trol see Fig 5 very few canard kits mar ket choose event youd like run out buy avail able unfortunately have no personal expe rience have refining jet-look canardtype aircraft better six years have much success fly very well can made very stable modified easily very aerobatic stronghearted pilot short discussion hope have given awareness some com plexities involved making canard air plane flyand intrigued enough will investigate Wonderful World Backwards Flight [When responding advertisers mention read about ModelAviation ment first thing apparent No maxed out Korda places sixth Robert Copland Eng land wins nine three-minute maxes made during entire contest assume Category III rules twominute maxes situation changes little Copland still wins max-out Korda fifth oniy 21 maxes made Zaic flying proxy Vincre France fails tie Copland second Now mean no disrespect Mr Korda other participant contest believe present Old-Timer Rubber fliers flying under current rules would score maxes did 1939 using same designs Ev idence such rash statement will found report 1986 SAM Society Antique ModelersEd Champs appeared October 1986 issue magazine meet Rubber Cabin flown two-minute maxes maxing out being allowed flyoff flight Five maxed out using OldTimer Wakefields three being 1939 Kordas 1936 design weather super-good day either would like share thoughts just fliers today get higher performance worlds best did 1939 designs have changed enforce weight rule judgement few underweight models result think fact total weight of todays Old-Timer Rubber models much different byContinued page 149 July1988 145 FF Old-Timers/Baker Continued page 57
Edition: Model Aviation - 1988/07
Page Numbers: 52, 53, 54, 56, 145
ne aunor nas nao mucn nanas-on experience wiin moaci canaras ne KflOW5 wnere OT ne speaks HI-Tech 2002 whIch has appearance Star Wars fighter 21st-century interceptor incorporates thrust-vectoring vane centered ducted-fan outlet TAIL-FIRST aircraft have intrigued minds men since Orville Wilbur pushed unstable canard Wright Flyer air Kitty Hawk Yes aircraft flew day terribly aft heavy Orville gone much higher did day probably would have done considerable damage himself craft What desperately needed thing called stability harder find canard-type aircraft answer will have come understanding con ventional aft-tail-configured aircraft Webster defines stability property body causes disturbed condition equilibrium steady motion develop forces moments restore original condition define sta bility pertains model alrcraft TAIL LIFT ability model correct its flight path after becoming upset gust pilot input Anyone has first flight new aft-tail aircraft found little sen sitive elevator has probably already flown unstable marginally-stable air craft Did land incident answered yes model probably marginally stable Did put six feet under yes model un stable out end arti cle will try simply describe stability differs canard aircraft conventional aft-tail aircraft will also refer negative stability NEGS unsta ble positive stability P05 stable neutral stability NUS Analogies will help understand three types stabilities go like golf-ball-sized steel ball center small slightly bowl-shaped table made soft clay going roll its own However tip table far enough will roll leave slight depression clay allowing return center table along path little effort analogous aircraft having POS softer clay POS father forward center gravity CG aircraft the POS Next imagine same ball flat glass-top table Although may roll right away will take slightest 52 Model Aviation breeze push set rolling also leaves no trail return may continue roll around till finds its way edge world analogous NUS real careful continued input angle table could keep ball near very center table much movement would case aircraft reach ing its aft-most CU position what some times have fuel tank nearly empty Finally imagine same ball same glass table outside gale-force windy day sensitive hands world arent going keep ball table never mind near center NEGS complete lack Full-scale model aircraft have three axes stability longitudinal elevator up sets stability lateral aileron upsets stability directional rudder up sets stability article will deal longitudinal stability control pertains canard aircraft Longitudinal stability aft-tail air craft dependent primarily upon CU posi tion and/or tail size build kit air planes build per plans oaly way can effect stability change move CU flew new model found floundering around sky its tail low probably surmised tail heavy moving CU forward things probably got better mov ing CU forward did seem help horizontal tail might too small en larging tail corrected problem have successfully beaten stability game putting pencil paper Canard airplanes obey same laws physics aft-tail aircraft However fine tuning kit canard scratch-built can lead some exciting gyrations sky Let explain First study Fig 1 As can see aft-tail aircraft gains its stability down loading tail force exerted tail constantly trying hold nose up force removed accidentally purpose nose drops prevents wing stall ing excessive angle attack reached tail begins produce up load bringing aircraft back horizon tal position reverse true nose aircraft gets too low tail creases its down load returning aircraft level Lets now move subject ques tion does canard-type aircraft get its stability Study Fig 2 canard-type aircraft can have herent built stability canard sur face made stall before main wing Loss lift canard surface allows nose drop preventing main wing stalls possibly spins just used word herent describing type stabil ity because todays super planeslike X-29athere artificial type sta bility gained use computers keep aircraft out trouble Lets assume have built yourself canard airplane took out fly first time finding very sensitive elevator input So moved CU forward tad found although airplane flew well going fast couldnt hold nose up high enough land slowly s too big decided would make canard elevator slightly larger produce lift turn tighter went out fly fix found out model wing heavy again So moved CU ward again calm airplane down loops got awful big again Feel like youre July 1988 53 Hi-Tech 2002 rotated tail-strike position Power OS Max 46 VR DF engine Kress RK-740 fan unit Design featured September 1986 MA full-size plan No 525 chasing tail Well literally Increasing canard size chang ing CO reduced stability creased control power same time making airplane unmanageable again some canard designs happy balance tween aerobatic performance good posi tive stability can achieved CO posi CT IONtion alone everything have done still does net performance wish go back aft-tail aircraft Really Im kidding Now have better understanding stability lets talk about control Control ling pitch axis canard-type air craft foreplane called canard planform shape although some impor tance stability control will IONissue method producing pitch-up pitch-down moments / IFigure 3 depicts four common methods producing pitching moment all-flying canard simple flapped ca ___________nard fixed canard both leading ___________trailing edge flaps all-flying canard leading edge device all-flying canard although simple construction no separate pieces addi tional moving parts prone damage hard nose-down landing cause supported single usu ally flimsy shaft However configura tion best producing large pitching moments tighter turns fixed canard trailing edge ele vator although common kits scratch builders worst four producing large pitching moments highly-loaded canard stability discussed earlier stalls easily high flap elevator deflections way get around premature stall problem modify canard next type third choice Fig 3 fixed ca nard flap leading edge device droop droop leading edge postContinued page 56 54 Model Aviation decorated model Hi-Tech 2000 plainer atop rocks Hi-Tech 2001 Design both nearly same though structures different H-T 2001 abandoned fiberglass fuselage H-T 2000 among other things came out about pound lighter heavier plane dog flight H-T 2001 flew sprightly its OS 25 VF DF engine RK-20 fan unit Hi-Tech 2001 available MA full-size plan number 456 TWO CYCLE AND DRILLED AND TSPPID TWO CYCLE ENGINE MOUNTS JE40ENYA 405S-45C1 4W40FOX 40 86 DELUXE JTKB2OK&BRtCSportster JT-kB45K & B RIG Spoflstar JT-KB6OK & B RIG Sporasoar JT4WOAIINE 20-25 RIG JT-lii30IRVINE 3040 RIG J11V61IRViNE 61 RIG J442OMAX 20-25 FP J1M25MAX 25 TSR JFM35MAX 35-40 PP JT-M40MAX 40 TSR JTh446MAX 405F-405F j1M50MAX50FSR JTM61MAX61ISRO1SF JtMIO6MAX 91-100 TSR JT-821SFIRAT 2125-29 JT-5T40Sr-COMO 4045-46 JT-5T51STG0M0 5100 JT-S1U1SIGOMO 61-75-90 JT-S13000 ST 2000-2500-3090 PYWAI RAGING M0UNS iTISPY 15 dIp 800 Jr-A WY 40 d0- 800 1000 JT42 1000 JT-40 800 JT-84 1000 JT-121 sinJT41 800 JT-49 500 JF2O 100 JM 800 JT-48 800 Jr-81 1000 JT-82 1000 JT122 1000 JT-43 100Jr-AS sinJ65 IBMJT123 800 1000 12WJ120 isinJr-AC 2500JT-80 JF120 FOUR CYCLE ENGINE MOUNTS DRILLED AND lAPPED FOUR CYCLE ENGINE MOUNTS ENYS 35-40 401000 ENYA 46 AG1000 ENYS 60-80-90-120 401300 ENVA R 120402000 HPVT211000 HPVT491300 MAXFS20800 MAX FS 40-40 Surpass1000 MAX FS48Suss1000 1100 MAX FS 60-75-901100 MAX 120-120 Surpass 2000 SAflOFA3O1000 SAnD F40-4S 1000 SAflDMi65 SArFOFA12O2000 mu Mirage 10-25 dls 800 Mirage 20-45 dia 800 Merage 50-80 diap 1100 Mirage 90-120 dIs 1800 FREE CATALOG cultpeCIt0tons 1It iVeeKS S US 01 WiO ourp8T e BS sA611 5tandOSeO055ti Ce1ed tb phli 91og %AS 68geB loclades HY-70B Motor 8-62 Battery 2 Props Charge Plug Coooector Accessory Pkg screws spacers etc VL-111BR$2795 Same VI-iliB bat HY-7OBR Mator Remote Flight Battery Holder MINI POWER AT ITS BEST t Weight l P-30 Size Models k Cl 7-1 Gear Ratio t ant Start Cost Battery Power ner FLIGHT BATTERIE HY-70B$1495 B-62 2uSD mAHr 9 gina Ao impruoed HY-70 Features reioforcedSoap ioto place motor prop shaft oeopreoe sleese eogageNo wiriog reouiredl diseogage Fae-wheeliog8-52 2u80 mAHr 13 gins .5 HY-7OBR$1795 Same B-62 motor-rue Same HY-70B equipped Remote 1 mioutes Flight Battery Holder er has 7 8-63 3a50 mAHr 13g... $13 5 irwl niiiel t1icnnnpcts Slide battery sowerful shorter motor-rue pones canard stall considerably ever said before little tricks canard will still stall before main wing because its relatively small size compared wing last alternative powerful pitch con trol solely canard all-flying canard leading edge device combination gives best pitch control very high deflections methods have draw backs whether structural aero dynamic choice use de pends highly overall configuration aircraft involved preference hap pens #3 Fig 3 because offers ex ceptional pitch control coupled good structural integrity due non-moving center section box aircraft designers call last subject would like touch upon thrust vectoring act using high energy air produced propel ler fan complementing canard pitch control small vane supported hind prop fan directly engine centerline vane mechanically coupled canard produce common up commands ie canard de vices commands up trailing edge vane moves up Any have flown close-coupled Control Line Com bat ships probably have some experi ence effect Combat en gine quits ship comes down hurry applying elevator input cant keep nose up airplane slows down Thrust vectoring some canard aircraft can mean saving ship has found its way phenomenon known deep stall Deep stall canard aircraft often fatal like dreaded flat spin con ventional aft-tail aircraft big differ ence deep stall aircraft rarely spins motion like maple leaf falling its branch high atop tree aircraft falls very slowly becomes uncontrollable aircraft literally falls straight ground upright inverted wings level no airflow over canard provide pitch control thrust vectoring nothing behind propel ler fan produce moment recover deep stall Thrust vectoring can thought complement canard pitch control aircraft saver should find canard airplane deep stall phenomenon Canard airplanes properly designed can just easy much fun fly afttail aircraft providing follow some basic rules Rule #1 Keep canard airfoil thick leading edge blunt prevent stalling too soon though have al ready made point canard has stall before wing order have POS Continued page 145 56 Model Aviation fully normal Pro-head flybarless system will have make ex cuses should consider what said pre view Legend some details may change before production begins However flew three prototypes am very impressed machines perform ance flexibility As expected come stock kit Legend nine-pound 60-class belt-driven tail flybarless rotor aerobatic rocket ship cause commonalties other GMP ma chines could add other GMP heads 1 1/2-in-longer belt-drive tail stan dard GMP shaft-drive tail could up date Competitor Cobra already own can literally style Legend suit current desires aerobatics Scale FAI competition Pick tail head suit task GMP also working new rotor head us ing proven dampening systembut mid-position underslung flybar way John Gorham works wont take long him fin ish Legend package various acces sories dedicated GMP expects early sum mer release sounds realistic Stay touch GMP dealer further updates So whats new department have apologize readers manufacturers have sent letters and/or products testing have extremely busy last six monthsboth daytime job McDonnell Douglas LIMP am process finishing third three consecutive movies last few months Ive built three fuselage plugs seven Helicoptersnone personal machines though Im doing lot flying havent done Please patient can see day light again really have urge finish up current projects some serious fun fly ing Now spring turning summer Ill bet lot afternoon-evening sport flying go ing over country Boy sure look ward joining fun BCNU Larry Canard Stability/Hunt Continued page 56 No matter what little tricks have preventing canard stalling will always stall before wing because its much smaller size air likes big surfaces run over better small onesReynolds effect Rule #2 Larger elevators canard small deflections better small elevators large deflections probably know also works eleva tors aft-tail aircraft control sur face model airplane Rule #3 Wings should have blunt leading edges and/or sufficient twist washout prevent tips stalling Rule #4 canard large span may wish washout canard tips well wing tips help prevent pre mature stall Rule #5 Get used idea flying airplane looks like its going reverse 100 mph biggest complaints airplane educated spectators can never tell way airplane going Perception problems will crash airplane faster design flaws Rule #6 Seal control surface gaps canard increase effectiveness Suggestion #1 using fixed ca nard trailing edge elevator consider using leading edge droop device pre vent premature canard stall see Fig 4 Suggestion #2 after fussing fighting canard design youre happy stability level still cant get turn tight loop small enough give some thought using thrust vectoring assist canard pitch con trol see Fig 5 very few canard kits mar ket choose event youd like run out buy avail able unfortunately have no personal expe rience have refining jet-look canardtype aircraft better six years have much success fly very well can made very stable modified easily very aerobatic stronghearted pilot short discussion hope have given awareness some com plexities involved making canard air plane flyand intrigued enough will investigate Wonderful World Backwards Flight [When responding advertisers mention read about ModelAviation ment first thing apparent No maxed out Korda places sixth Robert Copland Eng land wins nine three-minute maxes made during entire contest assume Category III rules twominute maxes situation changes little Copland still wins max-out Korda fifth oniy 21 maxes made Zaic flying proxy Vincre France fails tie Copland second Now mean no disrespect Mr Korda other participant contest believe present Old-Timer Rubber fliers flying under current rules would score maxes did 1939 using same designs Ev idence such rash statement will found report 1986 SAM Society Antique ModelersEd Champs appeared October 1986 issue magazine meet Rubber Cabin flown two-minute maxes maxing out being allowed flyoff flight Five maxed out using OldTimer Wakefields three being 1939 Kordas 1936 design weather super-good day either would like share thoughts just fliers today get higher performance worlds best did 1939 designs have changed enforce weight rule judgement few underweight models result think fact total weight of todays Old-Timer Rubber models much different byContinued page 149 July1988 145 FF Old-Timers/Baker Continued page 57
Edition: Model Aviation - 1988/07
Page Numbers: 52, 53, 54, 56, 145
ne aunor nas nao mucn nanas-on experience wiin moaci canaras ne KflOW5 wnere OT ne speaks HI-Tech 2002 whIch has appearance Star Wars fighter 21st-century interceptor incorporates thrust-vectoring vane centered ducted-fan outlet TAIL-FIRST aircraft have intrigued minds men since Orville Wilbur pushed unstable canard Wright Flyer air Kitty Hawk Yes aircraft flew day terribly aft heavy Orville gone much higher did day probably would have done considerable damage himself craft What desperately needed thing called stability harder find canard-type aircraft answer will have come understanding con ventional aft-tail-configured aircraft Webster defines stability property body causes disturbed condition equilibrium steady motion develop forces moments restore original condition define sta bility pertains model alrcraft TAIL LIFT ability model correct its flight path after becoming upset gust pilot input Anyone has first flight new aft-tail aircraft found little sen sitive elevator has probably already flown unstable marginally-stable air craft Did land incident answered yes model probably marginally stable Did put six feet under yes model un stable out end arti cle will try simply describe stability differs canard aircraft conventional aft-tail aircraft will also refer negative stability NEGS unsta ble positive stability P05 stable neutral stability NUS Analogies will help understand three types stabilities go like golf-ball-sized steel ball center small slightly bowl-shaped table made soft clay going roll its own However tip table far enough will roll leave slight depression clay allowing return center table along path little effort analogous aircraft having POS softer clay POS father forward center gravity CG aircraft the POS Next imagine same ball flat glass-top table Although may roll right away will take slightest 52 Model Aviation breeze push set rolling also leaves no trail return may continue roll around till finds its way edge world analogous NUS real careful continued input angle table could keep ball near very center table much movement would case aircraft reach ing its aft-most CU position what some times have fuel tank nearly empty Finally imagine same ball same glass table outside gale-force windy day sensitive hands world arent going keep ball table never mind near center NEGS complete lack Full-scale model aircraft have three axes stability longitudinal elevator up sets stability lateral aileron upsets stability directional rudder up sets stability article will deal longitudinal stability control pertains canard aircraft Longitudinal stability aft-tail air craft dependent primarily upon CU posi tion and/or tail size build kit air planes build per plans oaly way can effect stability change move CU flew new model found floundering around sky its tail low probably surmised tail heavy moving CU forward things probably got better mov ing CU forward did seem help horizontal tail might too small en larging tail corrected problem have successfully beaten stability game putting pencil paper Canard airplanes obey same laws physics aft-tail aircraft However fine tuning kit canard scratch-built can lead some exciting gyrations sky Let explain First study Fig 1 As can see aft-tail aircraft gains its stability down loading tail force exerted tail constantly trying hold nose up force removed accidentally purpose nose drops prevents wing stall ing excessive angle attack reached tail begins produce up load bringing aircraft back horizon tal position reverse true nose aircraft gets too low tail creases its down load returning aircraft level Lets now move subject ques tion does canard-type aircraft get its stability Study Fig 2 canard-type aircraft can have herent built stability canard sur face made stall before main wing Loss lift canard surface allows nose drop preventing main wing stalls possibly spins just used word herent describing type stabil ity because todays super planeslike X-29athere artificial type sta bility gained use computers keep aircraft out trouble Lets assume have built yourself canard airplane took out fly first time finding very sensitive elevator input So moved CU forward tad found although airplane flew well going fast couldnt hold nose up high enough land slowly s too big decided would make canard elevator slightly larger produce lift turn tighter went out fly fix found out model wing heavy again So moved CU ward again calm airplane down loops got awful big again Feel like youre July 1988 53 Hi-Tech 2002 rotated tail-strike position Power OS Max 46 VR DF engine Kress RK-740 fan unit Design featured September 1986 MA full-size plan No 525 chasing tail Well literally Increasing canard size chang ing CO reduced stability creased control power same time making airplane unmanageable again some canard designs happy balance tween aerobatic performance good posi tive stability can achieved CO posi CT IONtion alone everything have done still does net performance wish go back aft-tail aircraft Really Im kidding Now have better understanding stability lets talk about control Control ling pitch axis canard-type air craft foreplane called canard planform shape although some impor tance stability control will IONissue method producing pitch-up pitch-down moments / IFigure 3 depicts four common methods producing pitching moment all-flying canard simple flapped ca ___________nard fixed canard both leading ___________trailing edge flaps all-flying canard leading edge device all-flying canard although simple construction no separate pieces addi tional moving parts prone damage hard nose-down landing cause supported single usu ally flimsy shaft However configura tion best producing large pitching moments tighter turns fixed canard trailing edge ele vator although common kits scratch builders worst four producing large pitching moments highly-loaded canard stability discussed earlier stalls easily high flap elevator deflections way get around premature stall problem modify canard next type third choice Fig 3 fixed ca nard flap leading edge device droop droop leading edge postContinued page 56 54 Model Aviation decorated model Hi-Tech 2000 plainer atop rocks Hi-Tech 2001 Design both nearly same though structures different H-T 2001 abandoned fiberglass fuselage H-T 2000 among other things came out about pound lighter heavier plane dog flight H-T 2001 flew sprightly its OS 25 VF DF engine RK-20 fan unit Hi-Tech 2001 available MA full-size plan number 456 TWO CYCLE AND DRILLED AND TSPPID TWO CYCLE ENGINE MOUNTS JE40ENYA 405S-45C1 4W40FOX 40 86 DELUXE JTKB2OK&BRtCSportster JT-kB45K & B RIG Spoflstar JT-KB6OK & B RIG Sporasoar JT4WOAIINE 20-25 RIG JT-lii30IRVINE 3040 RIG J11V61IRViNE 61 RIG J442OMAX 20-25 FP J1M25MAX 25 TSR JFM35MAX 35-40 PP JT-M40MAX 40 TSR JTh446MAX 405F-405F j1M50MAX50FSR JTM61MAX61ISRO1SF JtMIO6MAX 91-100 TSR JT-821SFIRAT 2125-29 JT-5T40Sr-COMO 4045-46 JT-5T51STG0M0 5100 JT-S1U1SIGOMO 61-75-90 JT-S13000 ST 2000-2500-3090 PYWAI RAGING M0UNS iTISPY 15 dIp 800 Jr-A WY 40 d0- 800 1000 JT42 1000 JT-40 800 JT-84 1000 JT-121 sinJT41 800 JT-49 500 JF2O 100 JM 800 JT-48 800 Jr-81 1000 JT-82 1000 JT122 1000 JT-43 100Jr-AS sinJ65 IBMJT123 800 1000 12WJ120 isinJr-AC 2500JT-80 JF120 FOUR CYCLE ENGINE MOUNTS DRILLED AND lAPPED FOUR CYCLE ENGINE MOUNTS ENYS 35-40 401000 ENYA 46 AG1000 ENYS 60-80-90-120 401300 ENVA R 120402000 HPVT211000 HPVT491300 MAXFS20800 MAX FS 40-40 Surpass1000 MAX FS48Suss1000 1100 MAX FS 60-75-901100 MAX 120-120 Surpass 2000 SAflOFA3O1000 SAnD F40-4S 1000 SAflDMi65 SArFOFA12O2000 mu Mirage 10-25 dls 800 Mirage 20-45 dia 800 Merage 50-80 diap 1100 Mirage 90-120 dIs 1800 FREE CATALOG cultpeCIt0tons 1It iVeeKS S US 01 WiO ourp8T e BS sA611 5tandOSeO055ti Ce1ed tb phli 91og %AS 68geB loclades HY-70B Motor 8-62 Battery 2 Props Charge Plug Coooector Accessory Pkg screws spacers etc VL-111BR$2795 Same VI-iliB bat HY-7OBR Mator Remote Flight Battery Holder MINI POWER AT ITS BEST t Weight l P-30 Size Models k Cl 7-1 Gear Ratio t ant Start Cost Battery Power ner FLIGHT BATTERIE HY-70B$1495 B-62 2uSD mAHr 9 gina Ao impruoed HY-70 Features reioforcedSoap ioto place motor prop shaft oeopreoe sleese eogageNo wiriog reouiredl diseogage Fae-wheeliog8-52 2u80 mAHr 13 gins .5 HY-7OBR$1795 Same B-62 motor-rue Same HY-70B equipped Remote 1 mioutes Flight Battery Holder er has 7 8-63 3a50 mAHr 13g... $13 5 irwl niiiel t1icnnnpcts Slide battery sowerful shorter motor-rue pones canard stall considerably ever said before little tricks canard will still stall before main wing because its relatively small size compared wing last alternative powerful pitch con trol solely canard all-flying canard leading edge device combination gives best pitch control very high deflections methods have draw backs whether structural aero dynamic choice use de pends highly overall configuration aircraft involved preference hap pens #3 Fig 3 because offers ex ceptional pitch control coupled good structural integrity due non-moving center section box aircraft designers call last subject would like touch upon thrust vectoring act using high energy air produced propel ler fan complementing canard pitch control small vane supported hind prop fan directly engine centerline vane mechanically coupled canard produce common up commands ie canard de vices commands up trailing edge vane moves up Any have flown close-coupled Control Line Com bat ships probably have some experi ence effect Combat en gine quits ship comes down hurry applying elevator input cant keep nose up airplane slows down Thrust vectoring some canard aircraft can mean saving ship has found its way phenomenon known deep stall Deep stall canard aircraft often fatal like dreaded flat spin con ventional aft-tail aircraft big differ ence deep stall aircraft rarely spins motion like maple leaf falling its branch high atop tree aircraft falls very slowly becomes uncontrollable aircraft literally falls straight ground upright inverted wings level no airflow over canard provide pitch control thrust vectoring nothing behind propel ler fan produce moment recover deep stall Thrust vectoring can thought complement canard pitch control aircraft saver should find canard airplane deep stall phenomenon Canard airplanes properly designed can just easy much fun fly afttail aircraft providing follow some basic rules Rule #1 Keep canard airfoil thick leading edge blunt prevent stalling too soon though have al ready made point canard has stall before wing order have POS Continued page 145 56 Model Aviation fully normal Pro-head flybarless system will have make ex cuses should consider what said pre view Legend some details may change before production begins However flew three prototypes am very impressed machines perform ance flexibility As expected come stock kit Legend nine-pound 60-class belt-driven tail flybarless rotor aerobatic rocket ship cause commonalties other GMP ma chines could add other GMP heads 1 1/2-in-longer belt-drive tail stan dard GMP shaft-drive tail could up date Competitor Cobra already own can literally style Legend suit current desires aerobatics Scale FAI competition Pick tail head suit task GMP also working new rotor head us ing proven dampening systembut mid-position underslung flybar way John Gorham works wont take long him fin ish Legend package various acces sories dedicated GMP expects early sum mer release sounds realistic Stay touch GMP dealer further updates So whats new department have apologize readers manufacturers have sent letters and/or products testing have extremely busy last six monthsboth daytime job McDonnell Douglas LIMP am process finishing third three consecutive movies last few months Ive built three fuselage plugs seven Helicoptersnone personal machines though Im doing lot flying havent done Please patient can see day light again really have urge finish up current projects some serious fun fly ing Now spring turning summer Ill bet lot afternoon-evening sport flying go ing over country Boy sure look ward joining fun BCNU Larry Canard Stability/Hunt Continued page 56 No matter what little tricks have preventing canard stalling will always stall before wing because its much smaller size air likes big surfaces run over better small onesReynolds effect Rule #2 Larger elevators canard small deflections better small elevators large deflections probably know also works eleva tors aft-tail aircraft control sur face model airplane Rule #3 Wings should have blunt leading edges and/or sufficient twist washout prevent tips stalling Rule #4 canard large span may wish washout canard tips well wing tips help prevent pre mature stall Rule #5 Get used idea flying airplane looks like its going reverse 100 mph biggest complaints airplane educated spectators can never tell way airplane going Perception problems will crash airplane faster design flaws Rule #6 Seal control surface gaps canard increase effectiveness Suggestion #1 using fixed ca nard trailing edge elevator consider using leading edge droop device pre vent premature canard stall see Fig 4 Suggestion #2 after fussing fighting canard design youre happy stability level still cant get turn tight loop small enough give some thought using thrust vectoring assist canard pitch con trol see Fig 5 very few canard kits mar ket choose event youd like run out buy avail able unfortunately have no personal expe rience have refining jet-look canardtype aircraft better six years have much success fly very well can made very stable modified easily very aerobatic stronghearted pilot short discussion hope have given awareness some com plexities involved making canard air plane flyand intrigued enough will investigate Wonderful World Backwards Flight [When responding advertisers mention read about ModelAviation ment first thing apparent No maxed out Korda places sixth Robert Copland Eng land wins nine three-minute maxes made during entire contest assume Category III rules twominute maxes situation changes little Copland still wins max-out Korda fifth oniy 21 maxes made Zaic flying proxy Vincre France fails tie Copland second Now mean no disrespect Mr Korda other participant contest believe present Old-Timer Rubber fliers flying under current rules would score maxes did 1939 using same designs Ev idence such rash statement will found report 1986 SAM Society Antique ModelersEd Champs appeared October 1986 issue magazine meet Rubber Cabin flown two-minute maxes maxing out being allowed flyoff flight Five maxed out using OldTimer Wakefields three being 1939 Kordas 1936 design weather super-good day either would like share thoughts just fliers today get higher performance worlds best did 1939 designs have changed enforce weight rule judgement few underweight models result think fact total weight of todays Old-Timer Rubber models much different byContinued page 149 July1988 145 FF Old-Timers/Baker Continued page 57