1 SPORT AEROBATICS Ron Van Putte THE NEW AMA rule book contains inter esting change hadnt realized included should affect advance ment almost Pattern flier change initially appears minor consequently contestants Contest Directors probably havent realized impact change will have winner event will earn advancement points equal three times number people beats second place finisher will get points equal two times number people beats Everyone else entitled points equal number people beat What change can remember year finished fourth four contests didnt earn advancement points beat 21 other fliers contest three beat earned no points same thing happens year will earn 21 points According new AMA rule book contestant responsible keeping record own classification points will relieve Contest Director being deluged except last place finishers event does require contestant determine fliers beats before leaving contest site So scorers have bigger job past top three finishers identified All-in-all think new system great should break up logjam contestants Novice Advanced recently read article John Saville Thundervolts newsletter Thundervolts RC Club Schenectady NY first thought might another article downwind turn problem wasnt soon became apparent John knows what wrote about something interest RC pilots Accordingly what follows slightly edited version article Flying wind velocity gradientRC pilots flying portion earths atmosphere greatest wind velocity gradient namely first 400 feet above ground Understanding wind velocity gradient its influence aircraft can helpful explaining wind velocity gradient helpful think wind series thin horizontal layers air moving over ground Trees grass shrubs other obstructions tend slow air layer traveling next ground ground layer tends slow air layer moving above adjacent much layer above turn slowed decreas ing amounts overall effect wind velocity gradient increase wind velocity altitude greatest changes occur nearest ground uncommon have 25 30 mph wind 300 feet 10 15 mph ground effect wind velocity gradient can best experienced safely following experiment windy day aircraft 200 feet start 450 dive under power wind Pull out 50 feet full throttle climb 450 wind Notice long high plane continues before stalls out particularly noticeable trainer-type aircraft Now wingover repeat dive climb downwind first thing will notice much greater ground speed because airspeed craft wind velocity additive related wind velocity gradient second thing will notice quickly craft reaches stall point climbouL first climbout wind plane rising successive layers air increas ing wind velocity moving opposite direction aircraft thus adding its apparent air speed partially compensating its loss forward motion due climbout second climb downwind plane rising same successive layers air increasing wind velocity moving same direction aircraft thus reducing its appar ent airspeed bringing closer stall Therefore can deduce 1 Wind velocity gradient will add apparent airspeed climbing wind 2 wind velocity gradient will reduce apparent air speed climbing downwind descending wind 3 strong gusts wind momentarily magnify effects wind velocity gradient Some genera thoughts might keep mind flying wind velocity gradient 1 Stalls near ground moving upwind wind velocity gradient will result loss greater altitude stalls absence wind velocity gradients because plane will fall air moving lower velocities therefore keep landing speeds up 2 takeoffs climbouts directly Continued page 103 22 Model Aviation Bob Crump Oregon City OR prepares fly Curare Expert class 1979 Nationals Plane features OS Max 6OFSR OPS pipe Rhom Air retracts used dual rate aileron elevator built Hobby Barn kit weighed 9 lb Lori Crump helper Kevin Castaing placed 4th Novice class 1979 Nats Webra-powered Compensator New Iberia LA plane Southern R/C weighed 8/4 lb Futaba radio dual rate RC Giant Scale/Beckman Continued page 21 used flying completely around position ground difficulty staying side line envy flying sites must enjoy pilot shouldnt consider himself really qualified perform before spectators cant handle something relatively simple variations landing patterns Aside landing pattern qualms flying average best Ive seen flyin like some prangs few far between highlights Dave Landvaters flying 80-in-span scratch-built Pitts 20-lb Quadra-powered plane outstanding performer Dave uses 21 x 12 prop own design gets out engine/prop/plane combination would have believed possible Daves yes same Dave sunset performance 1 3-year-old 60-powered -scale Porterfield As rest us sat around fire talked quietly flew high enough catch reflections alreadyinvisible sun circled until ran out fuel brought venerable Porterfield down whistling series consecutive loops deadstick landing feet technical standpoint didnt see much really new 75 planes present Number-wise Quadra still dominates engine category four Kioritz powered planes flew impressive Scratchbuilt plan-built models far outnumbered kit types reversal trend last two years Only two Pitts seen Landvaters scratch-built Neil Hunts much-modified Byron kit Super Stearmans based Godfreys plans builders talked modified construction especially aft cockpit lighten tall Another trend noted earlier year Sacra mento apparently true East Coast well lack interest gear drives Olean Rudi Mayers six-yearold 1/5-scale Tiger Moth Rudi large Canadian group came down Kitchener-Waterloo area homemade gear drive HP 40 swings 16 x 6 prop flies six-foot span model authority controls seems drift away practice doubling-up aileron servos several planes one-piece wings single servo driving both four ailerons servos used usually 15 H 20H type seemed adequate flight situations However may warn ing few crashes occured alrcraft just gone through series rather violent maneuvers obviously prac ticed times short time later what meant gentle turn model rolled over went straight examination found square output drive servo rotated within socket output arm Dont underestimate stresses dealing Sunday chance talk Don Godfrey about progress new organiza tion launched Toledo last ApriL thing permanent name has selected Miniature Aircraft Society now International Miniature Aircraft Association truly international directors Canada France well throughout US constitution bylaws have prepared incorporation pending Selection logo about complete membership cards newsletter should out time read lot has done three months since Toledo meeting information contact Don Godfrey c/o Godfrey & Son Music 254 Washington St Binghamton NY 13901 As lead-in report said had almost perfect weekend thing kept total perfection fact didnt have anything fly rm looking forward perfect STARS-spangled weekend next year Fourth annual fly-in QSAA Fly-in set fourth go round Dates October 9-12 location Las Vegas NY years bash continues pattern set first three its dont want miss details write Ed Morgan 2310 Cimarron Rd Las Vegas NV 89117 call him 702 878-1306 after 10 am Las Vegas time Bob Beckman 8248 Holly Grove Cour* Manassas VA 22110 RC Aerobatics/Van Putte Continued page 22 wind get maximum climb rate 3 Maintain excess airspeed final approaches avoid stalling out descend through slower moving air overcome added effects gusts 4 Avoid long slow final approaches lead stalls ballooning Use steeper shorter finals 5 Consider using crosswind orientation doing series vertical maneuvers Pattern flying avoid sluggish climbs downwind Knowing people have jumped over discussions about effects wind aircraft recent years suggest potential letter writers carefully read Johns article before citing Continued page 108 October 1980 103 Yes rush copy new 6th edition Radio Control Buyers Guide Please check ElEnclosed $1100 $995 retail plus $105 postage US Canada Only dians send US Fundil El Charge El Mastercharge EVisa City State 7i- Return R/C Buyers Guide 7 Clifton House Clifton VA 22024 h-K S1ITt1@r Newtons Laws 20 years experience flying private airplanes other irrefutable sources support contradictory arguments Hes right Among several letters received recently two about same subject recommendation Dirty Birdy good beginning beyond Pattern airplane Dale Johnson APO New York thanked helping him make up mind other letter Glen Dean San Diego CA wrote agree Bridi Dirty Birdy good plane wholesale recommendation particular plane should tempered basic prerequisites such straight true aircraft built think too often people focus trend-setting fliers due regard became good illusion purchase right equipment suggests success advice misplaced believe fliers like Jim Kimbro Joe Bridi Jim Oddino could blow out us RCM Trainer other words believe person pushing sticks far away single largest factor Aircraftdesignis second ary aircraft trueness practice next trueness would prefer hear what Pattern fliers improve flying such practice techniques What concrete things big boys practice better maneuver Hes right course However airplanes make easier perform maneuvers theres no sense trying learn fly pattern competing inferior airplane objective recom mending Dirty Birdy solely give beginner good starting place competition Would like read about what big boys improve flying enough respond Ill try include several features subject Are hoarding good black-andwhite pictures could used column send few maybe youll become rich famous get $5 picture published have name picture caption So maybe wont become rich famousId still like get some good pictures Editors note Good quality color prints slides also acceptable also have received b&w Polaroid pictures acceptable quality use Ron Van Putte 12 Connie Drive Shalimar FL 32579 RC Helicopters/Chesney Continued page 23 fact spinning rotor acts gyroscope plus regard stability since gyroscope offers considerable resistance forces applied might tend change axis rotation faster gyroscope rotor spins resistance changewhich reason trend has higher rotor speeds past few years great argument variable collective pitch rather fixed col lective pitch Again rotor speeds approxi mately constant variable collective pitch used fixed collective pitch rotors must speed up slow down change lift rate gyroscope said have rigidity space persistent force applied upset spin axis gyroscope will react force 900 later direction rotation demonstration gyroscopic precession rigidity space recall old bicycle wheel demowhere grab axle spin wheel try yaw wheel right left Try Figure 2 shows what should happen compares rotor system bicycle wheel So maximum blade pitch occurs over rear fuselage Figure 1 result pitch felt 900 ahead due gyroscopic precession since blade creating lift has accelerated positive pitch blade will also tend bend flap upwards well opposite blade will tend flap downwards result gyroscopic precession blade flapping rotor disc will tend tilt right carrying main rotor shaft fuselage Perhaps tilt rotor disc would best shown now introduce another rotor head time well start fixed collective pitch head rather variable collective head shown previously Figure 3 shows typical fixed collective pitch head flybar rotor blades attached head bearings fixed head tilts side side blade positive other negative respect fixed collective pitch setting order tilt side side head attached gimbal allows movement rocking motion well Note flybar assembly part gimbal rocking flybar will cause head rock side side ends flybar paddles look like stub rotor blades fixed zero collective pitch setting like main rotor cyclic paddle rotated positive pitch other will become negative Pitch rotation flybar shaft means pushrod upper swash plate pitch arm flybar Now lets take look what happens servo rotor flybar using right roll example See Figure 4 First note linkage servo rotor pitch arm again 900 paddles effect servo rotor now same shape previous collective pitch example paddle over tail positive paddle over nose negative paddle over tail also process accelerating upward flapping approxi mately 900 later will its highest flap point Taking look attached main rotor hub blades see flybar 900 later seen rear has tilted rotor blade over tail now its greatest pitch angie accelerating its greatest flap angle opposite blade course accelerating downward Since head gimbal-mounted rotor disc will tilt Part thrust now available move helicopter right Figure 5 Since swash plate will tilt direction combinations longitudinal lateral cyclic may introduced helicopter can accelerated directionforward back ward right left combination directions way flybarless RC helicopters seem exception rather rule reason reduced torque required servo flybar rotor installation lower torque re quired servo current drain lower given servo batteries last longer As can see RC servo required tilt swash plate change pitch servo rotor servo rotor turn controls cyclic pitch main rotor Unfortunately response time suffers currently trend marry direct input main blades high response input flybar provide muscle mixing two methods has called BelIer System 108 Model Aviation
Edition: Model Aviation - 1980/10
Page Numbers: 22, 103, 108
1 SPORT AEROBATICS Ron Van Putte THE NEW AMA rule book contains inter esting change hadnt realized included should affect advance ment almost Pattern flier change initially appears minor consequently contestants Contest Directors probably havent realized impact change will have winner event will earn advancement points equal three times number people beats second place finisher will get points equal two times number people beats Everyone else entitled points equal number people beat What change can remember year finished fourth four contests didnt earn advancement points beat 21 other fliers contest three beat earned no points same thing happens year will earn 21 points According new AMA rule book contestant responsible keeping record own classification points will relieve Contest Director being deluged except last place finishers event does require contestant determine fliers beats before leaving contest site So scorers have bigger job past top three finishers identified All-in-all think new system great should break up logjam contestants Novice Advanced recently read article John Saville Thundervolts newsletter Thundervolts RC Club Schenectady NY first thought might another article downwind turn problem wasnt soon became apparent John knows what wrote about something interest RC pilots Accordingly what follows slightly edited version article Flying wind velocity gradientRC pilots flying portion earths atmosphere greatest wind velocity gradient namely first 400 feet above ground Understanding wind velocity gradient its influence aircraft can helpful explaining wind velocity gradient helpful think wind series thin horizontal layers air moving over ground Trees grass shrubs other obstructions tend slow air layer traveling next ground ground layer tends slow air layer moving above adjacent much layer above turn slowed decreas ing amounts overall effect wind velocity gradient increase wind velocity altitude greatest changes occur nearest ground uncommon have 25 30 mph wind 300 feet 10 15 mph ground effect wind velocity gradient can best experienced safely following experiment windy day aircraft 200 feet start 450 dive under power wind Pull out 50 feet full throttle climb 450 wind Notice long high plane continues before stalls out particularly noticeable trainer-type aircraft Now wingover repeat dive climb downwind first thing will notice much greater ground speed because airspeed craft wind velocity additive related wind velocity gradient second thing will notice quickly craft reaches stall point climbouL first climbout wind plane rising successive layers air increas ing wind velocity moving opposite direction aircraft thus adding its apparent air speed partially compensating its loss forward motion due climbout second climb downwind plane rising same successive layers air increasing wind velocity moving same direction aircraft thus reducing its appar ent airspeed bringing closer stall Therefore can deduce 1 Wind velocity gradient will add apparent airspeed climbing wind 2 wind velocity gradient will reduce apparent air speed climbing downwind descending wind 3 strong gusts wind momentarily magnify effects wind velocity gradient Some genera thoughts might keep mind flying wind velocity gradient 1 Stalls near ground moving upwind wind velocity gradient will result loss greater altitude stalls absence wind velocity gradients because plane will fall air moving lower velocities therefore keep landing speeds up 2 takeoffs climbouts directly Continued page 103 22 Model Aviation Bob Crump Oregon City OR prepares fly Curare Expert class 1979 Nationals Plane features OS Max 6OFSR OPS pipe Rhom Air retracts used dual rate aileron elevator built Hobby Barn kit weighed 9 lb Lori Crump helper Kevin Castaing placed 4th Novice class 1979 Nats Webra-powered Compensator New Iberia LA plane Southern R/C weighed 8/4 lb Futaba radio dual rate RC Giant Scale/Beckman Continued page 21 used flying completely around position ground difficulty staying side line envy flying sites must enjoy pilot shouldnt consider himself really qualified perform before spectators cant handle something relatively simple variations landing patterns Aside landing pattern qualms flying average best Ive seen flyin like some prangs few far between highlights Dave Landvaters flying 80-in-span scratch-built Pitts 20-lb Quadra-powered plane outstanding performer Dave uses 21 x 12 prop own design gets out engine/prop/plane combination would have believed possible Daves yes same Dave sunset performance 1 3-year-old 60-powered -scale Porterfield As rest us sat around fire talked quietly flew high enough catch reflections alreadyinvisible sun circled until ran out fuel brought venerable Porterfield down whistling series consecutive loops deadstick landing feet technical standpoint didnt see much really new 75 planes present Number-wise Quadra still dominates engine category four Kioritz powered planes flew impressive Scratchbuilt plan-built models far outnumbered kit types reversal trend last two years Only two Pitts seen Landvaters scratch-built Neil Hunts much-modified Byron kit Super Stearmans based Godfreys plans builders talked modified construction especially aft cockpit lighten tall Another trend noted earlier year Sacra mento apparently true East Coast well lack interest gear drives Olean Rudi Mayers six-yearold 1/5-scale Tiger Moth Rudi large Canadian group came down Kitchener-Waterloo area homemade gear drive HP 40 swings 16 x 6 prop flies six-foot span model authority controls seems drift away practice doubling-up aileron servos several planes one-piece wings single servo driving both four ailerons servos used usually 15 H 20H type seemed adequate flight situations However may warn ing few crashes occured alrcraft just gone through series rather violent maneuvers obviously prac ticed times short time later what meant gentle turn model rolled over went straight examination found square output drive servo rotated within socket output arm Dont underestimate stresses dealing Sunday chance talk Don Godfrey about progress new organiza tion launched Toledo last ApriL thing permanent name has selected Miniature Aircraft Society now International Miniature Aircraft Association truly international directors Canada France well throughout US constitution bylaws have prepared incorporation pending Selection logo about complete membership cards newsletter should out time read lot has done three months since Toledo meeting information contact Don Godfrey c/o Godfrey & Son Music 254 Washington St Binghamton NY 13901 As lead-in report said had almost perfect weekend thing kept total perfection fact didnt have anything fly rm looking forward perfect STARS-spangled weekend next year Fourth annual fly-in QSAA Fly-in set fourth go round Dates October 9-12 location Las Vegas NY years bash continues pattern set first three its dont want miss details write Ed Morgan 2310 Cimarron Rd Las Vegas NV 89117 call him 702 878-1306 after 10 am Las Vegas time Bob Beckman 8248 Holly Grove Cour* Manassas VA 22110 RC Aerobatics/Van Putte Continued page 22 wind get maximum climb rate 3 Maintain excess airspeed final approaches avoid stalling out descend through slower moving air overcome added effects gusts 4 Avoid long slow final approaches lead stalls ballooning Use steeper shorter finals 5 Consider using crosswind orientation doing series vertical maneuvers Pattern flying avoid sluggish climbs downwind Knowing people have jumped over discussions about effects wind aircraft recent years suggest potential letter writers carefully read Johns article before citing Continued page 108 October 1980 103 Yes rush copy new 6th edition Radio Control Buyers Guide Please check ElEnclosed $1100 $995 retail plus $105 postage US Canada Only dians send US Fundil El Charge El Mastercharge EVisa City State 7i- Return R/C Buyers Guide 7 Clifton House Clifton VA 22024 h-K S1ITt1@r Newtons Laws 20 years experience flying private airplanes other irrefutable sources support contradictory arguments Hes right Among several letters received recently two about same subject recommendation Dirty Birdy good beginning beyond Pattern airplane Dale Johnson APO New York thanked helping him make up mind other letter Glen Dean San Diego CA wrote agree Bridi Dirty Birdy good plane wholesale recommendation particular plane should tempered basic prerequisites such straight true aircraft built think too often people focus trend-setting fliers due regard became good illusion purchase right equipment suggests success advice misplaced believe fliers like Jim Kimbro Joe Bridi Jim Oddino could blow out us RCM Trainer other words believe person pushing sticks far away single largest factor Aircraftdesignis second ary aircraft trueness practice next trueness would prefer hear what Pattern fliers improve flying such practice techniques What concrete things big boys practice better maneuver Hes right course However airplanes make easier perform maneuvers theres no sense trying learn fly pattern competing inferior airplane objective recom mending Dirty Birdy solely give beginner good starting place competition Would like read about what big boys improve flying enough respond Ill try include several features subject Are hoarding good black-andwhite pictures could used column send few maybe youll become rich famous get $5 picture published have name picture caption So maybe wont become rich famousId still like get some good pictures Editors note Good quality color prints slides also acceptable also have received b&w Polaroid pictures acceptable quality use Ron Van Putte 12 Connie Drive Shalimar FL 32579 RC Helicopters/Chesney Continued page 23 fact spinning rotor acts gyroscope plus regard stability since gyroscope offers considerable resistance forces applied might tend change axis rotation faster gyroscope rotor spins resistance changewhich reason trend has higher rotor speeds past few years great argument variable collective pitch rather fixed col lective pitch Again rotor speeds approxi mately constant variable collective pitch used fixed collective pitch rotors must speed up slow down change lift rate gyroscope said have rigidity space persistent force applied upset spin axis gyroscope will react force 900 later direction rotation demonstration gyroscopic precession rigidity space recall old bicycle wheel demowhere grab axle spin wheel try yaw wheel right left Try Figure 2 shows what should happen compares rotor system bicycle wheel So maximum blade pitch occurs over rear fuselage Figure 1 result pitch felt 900 ahead due gyroscopic precession since blade creating lift has accelerated positive pitch blade will also tend bend flap upwards well opposite blade will tend flap downwards result gyroscopic precession blade flapping rotor disc will tend tilt right carrying main rotor shaft fuselage Perhaps tilt rotor disc would best shown now introduce another rotor head time well start fixed collective pitch head rather variable collective head shown previously Figure 3 shows typical fixed collective pitch head flybar rotor blades attached head bearings fixed head tilts side side blade positive other negative respect fixed collective pitch setting order tilt side side head attached gimbal allows movement rocking motion well Note flybar assembly part gimbal rocking flybar will cause head rock side side ends flybar paddles look like stub rotor blades fixed zero collective pitch setting like main rotor cyclic paddle rotated positive pitch other will become negative Pitch rotation flybar shaft means pushrod upper swash plate pitch arm flybar Now lets take look what happens servo rotor flybar using right roll example See Figure 4 First note linkage servo rotor pitch arm again 900 paddles effect servo rotor now same shape previous collective pitch example paddle over tail positive paddle over nose negative paddle over tail also process accelerating upward flapping approxi mately 900 later will its highest flap point Taking look attached main rotor hub blades see flybar 900 later seen rear has tilted rotor blade over tail now its greatest pitch angie accelerating its greatest flap angle opposite blade course accelerating downward Since head gimbal-mounted rotor disc will tilt Part thrust now available move helicopter right Figure 5 Since swash plate will tilt direction combinations longitudinal lateral cyclic may introduced helicopter can accelerated directionforward back ward right left combination directions way flybarless RC helicopters seem exception rather rule reason reduced torque required servo flybar rotor installation lower torque re quired servo current drain lower given servo batteries last longer As can see RC servo required tilt swash plate change pitch servo rotor servo rotor turn controls cyclic pitch main rotor Unfortunately response time suffers currently trend marry direct input main blades high response input flybar provide muscle mixing two methods has called BelIer System 108 Model Aviation
Edition: Model Aviation - 1980/10
Page Numbers: 22, 103, 108
1 SPORT AEROBATICS Ron Van Putte THE NEW AMA rule book contains inter esting change hadnt realized included should affect advance ment almost Pattern flier change initially appears minor consequently contestants Contest Directors probably havent realized impact change will have winner event will earn advancement points equal three times number people beats second place finisher will get points equal two times number people beats Everyone else entitled points equal number people beat What change can remember year finished fourth four contests didnt earn advancement points beat 21 other fliers contest three beat earned no points same thing happens year will earn 21 points According new AMA rule book contestant responsible keeping record own classification points will relieve Contest Director being deluged except last place finishers event does require contestant determine fliers beats before leaving contest site So scorers have bigger job past top three finishers identified All-in-all think new system great should break up logjam contestants Novice Advanced recently read article John Saville Thundervolts newsletter Thundervolts RC Club Schenectady NY first thought might another article downwind turn problem wasnt soon became apparent John knows what wrote about something interest RC pilots Accordingly what follows slightly edited version article Flying wind velocity gradientRC pilots flying portion earths atmosphere greatest wind velocity gradient namely first 400 feet above ground Understanding wind velocity gradient its influence aircraft can helpful explaining wind velocity gradient helpful think wind series thin horizontal layers air moving over ground Trees grass shrubs other obstructions tend slow air layer traveling next ground ground layer tends slow air layer moving above adjacent much layer above turn slowed decreas ing amounts overall effect wind velocity gradient increase wind velocity altitude greatest changes occur nearest ground uncommon have 25 30 mph wind 300 feet 10 15 mph ground effect wind velocity gradient can best experienced safely following experiment windy day aircraft 200 feet start 450 dive under power wind Pull out 50 feet full throttle climb 450 wind Notice long high plane continues before stalls out particularly noticeable trainer-type aircraft Now wingover repeat dive climb downwind first thing will notice much greater ground speed because airspeed craft wind velocity additive related wind velocity gradient second thing will notice quickly craft reaches stall point climbouL first climbout wind plane rising successive layers air increas ing wind velocity moving opposite direction aircraft thus adding its apparent air speed partially compensating its loss forward motion due climbout second climb downwind plane rising same successive layers air increasing wind velocity moving same direction aircraft thus reducing its appar ent airspeed bringing closer stall Therefore can deduce 1 Wind velocity gradient will add apparent airspeed climbing wind 2 wind velocity gradient will reduce apparent air speed climbing downwind descending wind 3 strong gusts wind momentarily magnify effects wind velocity gradient Some genera thoughts might keep mind flying wind velocity gradient 1 Stalls near ground moving upwind wind velocity gradient will result loss greater altitude stalls absence wind velocity gradients because plane will fall air moving lower velocities therefore keep landing speeds up 2 takeoffs climbouts directly Continued page 103 22 Model Aviation Bob Crump Oregon City OR prepares fly Curare Expert class 1979 Nationals Plane features OS Max 6OFSR OPS pipe Rhom Air retracts used dual rate aileron elevator built Hobby Barn kit weighed 9 lb Lori Crump helper Kevin Castaing placed 4th Novice class 1979 Nats Webra-powered Compensator New Iberia LA plane Southern R/C weighed 8/4 lb Futaba radio dual rate RC Giant Scale/Beckman Continued page 21 used flying completely around position ground difficulty staying side line envy flying sites must enjoy pilot shouldnt consider himself really qualified perform before spectators cant handle something relatively simple variations landing patterns Aside landing pattern qualms flying average best Ive seen flyin like some prangs few far between highlights Dave Landvaters flying 80-in-span scratch-built Pitts 20-lb Quadra-powered plane outstanding performer Dave uses 21 x 12 prop own design gets out engine/prop/plane combination would have believed possible Daves yes same Dave sunset performance 1 3-year-old 60-powered -scale Porterfield As rest us sat around fire talked quietly flew high enough catch reflections alreadyinvisible sun circled until ran out fuel brought venerable Porterfield down whistling series consecutive loops deadstick landing feet technical standpoint didnt see much really new 75 planes present Number-wise Quadra still dominates engine category four Kioritz powered planes flew impressive Scratchbuilt plan-built models far outnumbered kit types reversal trend last two years Only two Pitts seen Landvaters scratch-built Neil Hunts much-modified Byron kit Super Stearmans based Godfreys plans builders talked modified construction especially aft cockpit lighten tall Another trend noted earlier year Sacra mento apparently true East Coast well lack interest gear drives Olean Rudi Mayers six-yearold 1/5-scale Tiger Moth Rudi large Canadian group came down Kitchener-Waterloo area homemade gear drive HP 40 swings 16 x 6 prop flies six-foot span model authority controls seems drift away practice doubling-up aileron servos several planes one-piece wings single servo driving both four ailerons servos used usually 15 H 20H type seemed adequate flight situations However may warn ing few crashes occured alrcraft just gone through series rather violent maneuvers obviously prac ticed times short time later what meant gentle turn model rolled over went straight examination found square output drive servo rotated within socket output arm Dont underestimate stresses dealing Sunday chance talk Don Godfrey about progress new organiza tion launched Toledo last ApriL thing permanent name has selected Miniature Aircraft Society now International Miniature Aircraft Association truly international directors Canada France well throughout US constitution bylaws have prepared incorporation pending Selection logo about complete membership cards newsletter should out time read lot has done three months since Toledo meeting information contact Don Godfrey c/o Godfrey & Son Music 254 Washington St Binghamton NY 13901 As lead-in report said had almost perfect weekend thing kept total perfection fact didnt have anything fly rm looking forward perfect STARS-spangled weekend next year Fourth annual fly-in QSAA Fly-in set fourth go round Dates October 9-12 location Las Vegas NY years bash continues pattern set first three its dont want miss details write Ed Morgan 2310 Cimarron Rd Las Vegas NV 89117 call him 702 878-1306 after 10 am Las Vegas time Bob Beckman 8248 Holly Grove Cour* Manassas VA 22110 RC Aerobatics/Van Putte Continued page 22 wind get maximum climb rate 3 Maintain excess airspeed final approaches avoid stalling out descend through slower moving air overcome added effects gusts 4 Avoid long slow final approaches lead stalls ballooning Use steeper shorter finals 5 Consider using crosswind orientation doing series vertical maneuvers Pattern flying avoid sluggish climbs downwind Knowing people have jumped over discussions about effects wind aircraft recent years suggest potential letter writers carefully read Johns article before citing Continued page 108 October 1980 103 Yes rush copy new 6th edition Radio Control Buyers Guide Please check ElEnclosed $1100 $995 retail plus $105 postage US Canada Only dians send US Fundil El Charge El Mastercharge EVisa City State 7i- Return R/C Buyers Guide 7 Clifton House Clifton VA 22024 h-K S1ITt1@r Newtons Laws 20 years experience flying private airplanes other irrefutable sources support contradictory arguments Hes right Among several letters received recently two about same subject recommendation Dirty Birdy good beginning beyond Pattern airplane Dale Johnson APO New York thanked helping him make up mind other letter Glen Dean San Diego CA wrote agree Bridi Dirty Birdy good plane wholesale recommendation particular plane should tempered basic prerequisites such straight true aircraft built think too often people focus trend-setting fliers due regard became good illusion purchase right equipment suggests success advice misplaced believe fliers like Jim Kimbro Joe Bridi Jim Oddino could blow out us RCM Trainer other words believe person pushing sticks far away single largest factor Aircraftdesignis second ary aircraft trueness practice next trueness would prefer hear what Pattern fliers improve flying such practice techniques What concrete things big boys practice better maneuver Hes right course However airplanes make easier perform maneuvers theres no sense trying learn fly pattern competing inferior airplane objective recom mending Dirty Birdy solely give beginner good starting place competition Would like read about what big boys improve flying enough respond Ill try include several features subject Are hoarding good black-andwhite pictures could used column send few maybe youll become rich famous get $5 picture published have name picture caption So maybe wont become rich famousId still like get some good pictures Editors note Good quality color prints slides also acceptable also have received b&w Polaroid pictures acceptable quality use Ron Van Putte 12 Connie Drive Shalimar FL 32579 RC Helicopters/Chesney Continued page 23 fact spinning rotor acts gyroscope plus regard stability since gyroscope offers considerable resistance forces applied might tend change axis rotation faster gyroscope rotor spins resistance changewhich reason trend has higher rotor speeds past few years great argument variable collective pitch rather fixed col lective pitch Again rotor speeds approxi mately constant variable collective pitch used fixed collective pitch rotors must speed up slow down change lift rate gyroscope said have rigidity space persistent force applied upset spin axis gyroscope will react force 900 later direction rotation demonstration gyroscopic precession rigidity space recall old bicycle wheel demowhere grab axle spin wheel try yaw wheel right left Try Figure 2 shows what should happen compares rotor system bicycle wheel So maximum blade pitch occurs over rear fuselage Figure 1 result pitch felt 900 ahead due gyroscopic precession since blade creating lift has accelerated positive pitch blade will also tend bend flap upwards well opposite blade will tend flap downwards result gyroscopic precession blade flapping rotor disc will tend tilt right carrying main rotor shaft fuselage Perhaps tilt rotor disc would best shown now introduce another rotor head time well start fixed collective pitch head rather variable collective head shown previously Figure 3 shows typical fixed collective pitch head flybar rotor blades attached head bearings fixed head tilts side side blade positive other negative respect fixed collective pitch setting order tilt side side head attached gimbal allows movement rocking motion well Note flybar assembly part gimbal rocking flybar will cause head rock side side ends flybar paddles look like stub rotor blades fixed zero collective pitch setting like main rotor cyclic paddle rotated positive pitch other will become negative Pitch rotation flybar shaft means pushrod upper swash plate pitch arm flybar Now lets take look what happens servo rotor flybar using right roll example See Figure 4 First note linkage servo rotor pitch arm again 900 paddles effect servo rotor now same shape previous collective pitch example paddle over tail positive paddle over nose negative paddle over tail also process accelerating upward flapping approxi mately 900 later will its highest flap point Taking look attached main rotor hub blades see flybar 900 later seen rear has tilted rotor blade over tail now its greatest pitch angie accelerating its greatest flap angle opposite blade course accelerating downward Since head gimbal-mounted rotor disc will tilt Part thrust now available move helicopter right Figure 5 Since swash plate will tilt direction combinations longitudinal lateral cyclic may introduced helicopter can accelerated directionforward back ward right left combination directions way flybarless RC helicopters seem exception rather rule reason reduced torque required servo flybar rotor installation lower torque re quired servo current drain lower given servo batteries last longer As can see RC servo required tilt swash plate change pitch servo rotor servo rotor turn controls cyclic pitch main rotor Unfortunately response time suffers currently trend marry direct input main blades high response input flybar provide muscle mixing two methods has called BelIer System 108 Model Aviation