HELICOPTERS Dave Chesney IN THE last column took look collec tive pitch mechanism changing pitch tail rotor also introduced some similarities tail rotor collective main rotor collective oftwo-blade rigid rotor systems flybarless two-blade rigid rotor system has chosen because generally less mechanically compli cated compared rotor systems using flybar since control input introduced directly rotor blades rather through flybar sometimes called servo rotor addition flybarless system like tail rotor since blades free pivot about feathering axis otherwise rigidly attached rotor hub rigid rotors really rigid will see following introduce cyclic pitch changes rotor control -iZ--BLADE ANGLE NEGATIVE NOSE ROTOR HEAD PITCH ARMRLADE HOLDER PUSH ROD/ BPUS ROD BLADE ANGLE TIVE OVER~ SWASH PLATE~~ c TAIL TILT ANGLE ------- -~YS D PUSH RODS FROM SERVO FIGURE I----------IFORCE REACTS ROTATONHEREHERE t 90SPIN900 CW ROTATION AXISjTII# PULLMaT ON PUSH MOTION90 REACTSLFORCE APPLIED WHEEL REACTS HERE ERE BY TRYING TO TILT~SPIN AXIS FORCE APPLIED IN THIS MANNER AS IF TRYING 10 TURN BICYCLE WHEEL ROTOR DISC purposes Last month described main rotor col lective pitch changes transmitted servo through sliding swash plate pitch arms rotor blades Since linkages swash plate blades would move equally both blades would change pitch equally action taking place swash plate would move up down main rotor shaft similar action collective spider tail rotor example sliding swash plate method collective changes way get job done will discuss later fairly simple since flybarless rotor example mixing accom plished bellcranks within fuselage below non-revolving part swash plate way got little carried away made mistake sketch July column relating cyclic controland specifically regard position rotor blades maximum minimum pitch right roll following will clearly illustrate error time disregard linkage below swash plate lets now concentrate what happens swash plate tilted cyclic pitch changes Figure 1 illustrates swash plate tilted right would viewed left rear helicopter blades aligned centerline fuselage swash plate tilted right would result right roll forward flight right lateral motion hover Note blade over rear fuselage shown stopped maximum blade pitch Assigning letters 900 points swash platepoint high point C low points B Dare same level Also note rear blade rotated 900 clockwise opposite blade subject same pitch input since linkages would riding same level reason blade pitch arms connected swash plate linkages way due gyroscopic precession Continued page 108 SERVO ROTOR CHANGES PITCH B TILTS MAIN ROTOR CHANGES PITCH AS SERVO ROTOR TILTS SERVO ROTOR FIGURE 2 FIGURE 3 40--SERVO ROTOR TILT 411GIMBAL ASSEMBLY I-Ik u ________C SWASH PLATE TILT ANGLE9OL FIGURE 4 TO CYCLIC SERVO AILERON CHANNEL TO CYCLIC SERVO ELEVATOR CHANNEL REAR VIEWK WITH ROTOR DISC TILTED SOME THRUST IS USED FOR SIDEWAYS MOVEMENT HELl SLIDES RIGHT FIGURE 5 October 198023 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 Some examples Belier rotor head linkages will given next month See way have new ham radio callN4DFH no gear Ill have build super radio helicopter ala George Myers Ace Silver Seven Nice 4 Dave Eying Helicopters Dave Chesney Rt 9 Box 62 IA Greensboro NC 27409 RC Scale/Wischers Continued page 25 Powers recent articles MA relatively complete being tried true tool engineer Just other parameters model simply full-scale value divided scale factor weight area horsepower name few neither scale speed has go literature apply However since arent using radar timing traps like accurately measure scale speed such precision calculation measurement unnecessary What required workable approach determination flight realism scale speed however measured being factor have victimin scale modeling pursuits along East Coastof two miscon ceptions largely product ruminations John Preston have lot respect 1 flight realism consists scale speed 2 realistic speed slow last years Bealeton Scale Meet let hasten say well run complete pleasure placed third Sport Scale Byron Pitts flown plane fairly putt-putted around sky being marginal edge underpowered no vertical perform ance loops small rolls slow judges following guidance slow good slower gooder felt plane flying excellent scale speed However astonished during full-scale airshow followed meet Pitts Special tore up sky its blazing speed seemingly un limited vertical capability crisp maneuvers agreed surprise model Pitts too slow never thought Id ever hear Youve hit nail head coin phrase answer judge flight realism whole range factors overall speed being just factors Heres start few items might include some future guide flight realism judging Does model use throttle flight control No aircraft Im aware completes loop full throttle runs wide open through out entire flight 2 Are maneuvers chosen appropriate aircraft modeled Ever see scale business aircraft execute loop option scored Ever see model P-5 1 make inverted pass deck real couldnt wouldnt have done could realistic model like manner aerobatically capable subject flown through four different names straight level flight such strafing run missed approach overshoot etc must also downgraded realism 3 Are maneuvers properly chosen executed realistic manner Ive seen scale P-39 execute axial roll little its fuselage length get high marks Ive seen retracts get 9 10 score total retractextend cycle lasted no longer blink Realistic 4 entire flight realistic just chosen maneuvers plane retract gear Add $2 shipping N Y State residents add tax Dealer inquiries invited Name jAddress _____________ AptI ICityStateZip I0 Master Charge C Visa El Expiration DateI ICard NoI C Check enclosed $I SignatureI October 1980 109 WORLD WAR II Build 5 Profile Aircraft ENTERPRISE book 11 14 contains 8 E Atchiaon 3 different color schemes aircraft construction views dena CA 91104 full size templets Just trace cut shape glue paint youre$650 Shiepins cal Res ready goadd sales tax
Edition: Model Aviation - 1980/10
Page Numbers: 23, 108, 109
HELICOPTERS Dave Chesney IN THE last column took look collec tive pitch mechanism changing pitch tail rotor also introduced some similarities tail rotor collective main rotor collective oftwo-blade rigid rotor systems flybarless two-blade rigid rotor system has chosen because generally less mechanically compli cated compared rotor systems using flybar since control input introduced directly rotor blades rather through flybar sometimes called servo rotor addition flybarless system like tail rotor since blades free pivot about feathering axis otherwise rigidly attached rotor hub rigid rotors really rigid will see following introduce cyclic pitch changes rotor control -iZ--BLADE ANGLE NEGATIVE NOSE ROTOR HEAD PITCH ARMRLADE HOLDER PUSH ROD/ BPUS ROD BLADE ANGLE TIVE OVER~ SWASH PLATE~~ c TAIL TILT ANGLE ------- -~YS D PUSH RODS FROM SERVO FIGURE I----------IFORCE REACTS ROTATONHEREHERE t 90SPIN900 CW ROTATION AXISjTII# PULLMaT ON PUSH MOTION90 REACTSLFORCE APPLIED WHEEL REACTS HERE ERE BY TRYING TO TILT~SPIN AXIS FORCE APPLIED IN THIS MANNER AS IF TRYING 10 TURN BICYCLE WHEEL ROTOR DISC purposes Last month described main rotor col lective pitch changes transmitted servo through sliding swash plate pitch arms rotor blades Since linkages swash plate blades would move equally both blades would change pitch equally action taking place swash plate would move up down main rotor shaft similar action collective spider tail rotor example sliding swash plate method collective changes way get job done will discuss later fairly simple since flybarless rotor example mixing accom plished bellcranks within fuselage below non-revolving part swash plate way got little carried away made mistake sketch July column relating cyclic controland specifically regard position rotor blades maximum minimum pitch right roll following will clearly illustrate error time disregard linkage below swash plate lets now concentrate what happens swash plate tilted cyclic pitch changes Figure 1 illustrates swash plate tilted right would viewed left rear helicopter blades aligned centerline fuselage swash plate tilted right would result right roll forward flight right lateral motion hover Note blade over rear fuselage shown stopped maximum blade pitch Assigning letters 900 points swash platepoint high point C low points B Dare same level Also note rear blade rotated 900 clockwise opposite blade subject same pitch input since linkages would riding same level reason blade pitch arms connected swash plate linkages way due gyroscopic precession Continued page 108 SERVO ROTOR CHANGES PITCH B TILTS MAIN ROTOR CHANGES PITCH AS SERVO ROTOR TILTS SERVO ROTOR FIGURE 2 FIGURE 3 40--SERVO ROTOR TILT 411GIMBAL ASSEMBLY I-Ik u ________C SWASH PLATE TILT ANGLE9OL FIGURE 4 TO CYCLIC SERVO AILERON CHANNEL TO CYCLIC SERVO ELEVATOR CHANNEL REAR VIEWK WITH ROTOR DISC TILTED SOME THRUST IS USED FOR SIDEWAYS MOVEMENT HELl SLIDES RIGHT FIGURE 5 October 198023 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 Some examples Belier rotor head linkages will given next month See way have new ham radio callN4DFH no gear Ill have build super radio helicopter ala George Myers Ace Silver Seven Nice 4 Dave Eying Helicopters Dave Chesney Rt 9 Box 62 IA Greensboro NC 27409 RC Scale/Wischers Continued page 25 Powers recent articles MA relatively complete being tried true tool engineer Just other parameters model simply full-scale value divided scale factor weight area horsepower name few neither scale speed has go literature apply However since arent using radar timing traps like accurately measure scale speed such precision calculation measurement unnecessary What required workable approach determination flight realism scale speed however measured being factor have victimin scale modeling pursuits along East Coastof two miscon ceptions largely product ruminations John Preston have lot respect 1 flight realism consists scale speed 2 realistic speed slow last years Bealeton Scale Meet let hasten say well run complete pleasure placed third Sport Scale Byron Pitts flown plane fairly putt-putted around sky being marginal edge underpowered no vertical perform ance loops small rolls slow judges following guidance slow good slower gooder felt plane flying excellent scale speed However astonished during full-scale airshow followed meet Pitts Special tore up sky its blazing speed seemingly un limited vertical capability crisp maneuvers agreed surprise model Pitts too slow never thought Id ever hear Youve hit nail head coin phrase answer judge flight realism whole range factors overall speed being just factors Heres start few items might include some future guide flight realism judging Does model use throttle flight control No aircraft Im aware completes loop full throttle runs wide open through out entire flight 2 Are maneuvers chosen appropriate aircraft modeled Ever see scale business aircraft execute loop option scored Ever see model P-5 1 make inverted pass deck real couldnt wouldnt have done could realistic model like manner aerobatically capable subject flown through four different names straight level flight such strafing run missed approach overshoot etc must also downgraded realism 3 Are maneuvers properly chosen executed realistic manner Ive seen scale P-39 execute axial roll little its fuselage length get high marks Ive seen retracts get 9 10 score total retractextend cycle lasted no longer blink Realistic 4 entire flight realistic just chosen maneuvers plane retract gear Add $2 shipping N Y State residents add tax Dealer inquiries invited Name jAddress _____________ AptI ICityStateZip I0 Master Charge C Visa El Expiration DateI ICard NoI C Check enclosed $I SignatureI October 1980 109 WORLD WAR II Build 5 Profile Aircraft ENTERPRISE book 11 14 contains 8 E Atchiaon 3 different color schemes aircraft construction views dena CA 91104 full size templets Just trace cut shape glue paint youre$650 Shiepins cal Res ready goadd sales tax
Edition: Model Aviation - 1980/10
Page Numbers: 23, 108, 109
HELICOPTERS Dave Chesney IN THE last column took look collec tive pitch mechanism changing pitch tail rotor also introduced some similarities tail rotor collective main rotor collective oftwo-blade rigid rotor systems flybarless two-blade rigid rotor system has chosen because generally less mechanically compli cated compared rotor systems using flybar since control input introduced directly rotor blades rather through flybar sometimes called servo rotor addition flybarless system like tail rotor since blades free pivot about feathering axis otherwise rigidly attached rotor hub rigid rotors really rigid will see following introduce cyclic pitch changes rotor control -iZ--BLADE ANGLE NEGATIVE NOSE ROTOR HEAD PITCH ARMRLADE HOLDER PUSH ROD/ BPUS ROD BLADE ANGLE TIVE OVER~ SWASH PLATE~~ c TAIL TILT ANGLE ------- -~YS D PUSH RODS FROM SERVO FIGURE I----------IFORCE REACTS ROTATONHEREHERE t 90SPIN900 CW ROTATION AXISjTII# PULLMaT ON PUSH MOTION90 REACTSLFORCE APPLIED WHEEL REACTS HERE ERE BY TRYING TO TILT~SPIN AXIS FORCE APPLIED IN THIS MANNER AS IF TRYING 10 TURN BICYCLE WHEEL ROTOR DISC purposes Last month described main rotor col lective pitch changes transmitted servo through sliding swash plate pitch arms rotor blades Since linkages swash plate blades would move equally both blades would change pitch equally action taking place swash plate would move up down main rotor shaft similar action collective spider tail rotor example sliding swash plate method collective changes way get job done will discuss later fairly simple since flybarless rotor example mixing accom plished bellcranks within fuselage below non-revolving part swash plate way got little carried away made mistake sketch July column relating cyclic controland specifically regard position rotor blades maximum minimum pitch right roll following will clearly illustrate error time disregard linkage below swash plate lets now concentrate what happens swash plate tilted cyclic pitch changes Figure 1 illustrates swash plate tilted right would viewed left rear helicopter blades aligned centerline fuselage swash plate tilted right would result right roll forward flight right lateral motion hover Note blade over rear fuselage shown stopped maximum blade pitch Assigning letters 900 points swash platepoint high point C low points B Dare same level Also note rear blade rotated 900 clockwise opposite blade subject same pitch input since linkages would riding same level reason blade pitch arms connected swash plate linkages way due gyroscopic precession Continued page 108 SERVO ROTOR CHANGES PITCH B TILTS MAIN ROTOR CHANGES PITCH AS SERVO ROTOR TILTS SERVO ROTOR FIGURE 2 FIGURE 3 40--SERVO ROTOR TILT 411GIMBAL ASSEMBLY I-Ik u ________C SWASH PLATE TILT ANGLE9OL FIGURE 4 TO CYCLIC SERVO AILERON CHANNEL TO CYCLIC SERVO ELEVATOR CHANNEL REAR VIEWK WITH ROTOR DISC TILTED SOME THRUST IS USED FOR SIDEWAYS MOVEMENT HELl SLIDES RIGHT FIGURE 5 October 198023 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 Some examples Belier rotor head linkages will given next month See way have new ham radio callN4DFH no gear Ill have build super radio helicopter ala George Myers Ace Silver Seven Nice 4 Dave Eying Helicopters Dave Chesney Rt 9 Box 62 IA Greensboro NC 27409 RC Scale/Wischers Continued page 25 Powers recent articles MA relatively complete being tried true tool engineer Just other parameters model simply full-scale value divided scale factor weight area horsepower name few neither scale speed has go literature apply However since arent using radar timing traps like accurately measure scale speed such precision calculation measurement unnecessary What required workable approach determination flight realism scale speed however measured being factor have victimin scale modeling pursuits along East Coastof two miscon ceptions largely product ruminations John Preston have lot respect 1 flight realism consists scale speed 2 realistic speed slow last years Bealeton Scale Meet let hasten say well run complete pleasure placed third Sport Scale Byron Pitts flown plane fairly putt-putted around sky being marginal edge underpowered no vertical perform ance loops small rolls slow judges following guidance slow good slower gooder felt plane flying excellent scale speed However astonished during full-scale airshow followed meet Pitts Special tore up sky its blazing speed seemingly un limited vertical capability crisp maneuvers agreed surprise model Pitts too slow never thought Id ever hear Youve hit nail head coin phrase answer judge flight realism whole range factors overall speed being just factors Heres start few items might include some future guide flight realism judging Does model use throttle flight control No aircraft Im aware completes loop full throttle runs wide open through out entire flight 2 Are maneuvers chosen appropriate aircraft modeled Ever see scale business aircraft execute loop option scored Ever see model P-5 1 make inverted pass deck real couldnt wouldnt have done could realistic model like manner aerobatically capable subject flown through four different names straight level flight such strafing run missed approach overshoot etc must also downgraded realism 3 Are maneuvers properly chosen executed realistic manner Ive seen scale P-39 execute axial roll little its fuselage length get high marks Ive seen retracts get 9 10 score total retractextend cycle lasted no longer blink Realistic 4 entire flight realistic just chosen maneuvers plane retract gear Add $2 shipping N Y State residents add tax Dealer inquiries invited Name jAddress _____________ AptI ICityStateZip I0 Master Charge C Visa El Expiration DateI ICard NoI C Check enclosed $I SignatureI October 1980 109 WORLD WAR II Build 5 Profile Aircraft ENTERPRISE book 11 14 contains 8 E Atchiaon 3 different color schemes aircraft construction views dena CA 91104 full size templets Just trace cut shape glue paint youre$650 Shiepins cal Res ready goadd sales tax