LAST MONTH took look Gorham Model Products new Legend flybarless-rotor-head sport/competition machine recall really liked Legends aerobatic prowess excep tional autorotation capabilities pick up left off Ive now got experience Legendabout five gal lons hard flyings worth Nothing has cracked fallen off have found few things watch out First keep tail rotor drive belt tight Its dif ficult describe tight makes right Its basically set properly cant rotate main rotor restraining tail rotor course must no excessive drag sys tem run tail rotor belt too loose could wear out front plastic drive pinion occurs recourse replace pin Ion symptom loose belt glitchy tail hover rapid collective pitch movements applied almost looks like ship has gyro rate too sensitive resulting hunting yaw other thing look Teflon washers collective pitch pivot will eventu ally wear will need replaced restore units original slop-free condition Last month mentioned flybarless models fly little differently used fact will gist report Flybarless models seem get perpetual bad rap Horizon won Nats general consensus Horizon rea sonable machine Hubert Bitner won de spite lack flybar So whats difference between ship has flybar flybarless obvious answer ybar Just what steel rod its two little pad dles doing us Basically Hiller flybar al lows us feed control inputs flybar turn controls main rotor blades done disturbing rotor disc flybar re turns its neutral setting forces main ro tor blades feather neutral position So effect flybar adds autostabilization ro tor head flybar also goes action rotor disc acted upon outside force such gust wind As know Hiller sys tems superstablebut also tend slow reacting control input response rate can course increased adding mixer input directly blades known Bell/Hiller system modem flybar systems based generally accepted norm basic modifications being make head tighter looser depending method dampening So what happens throw flybar away Well first thing decrease drag Note Larrys Legend equipped Larry Chris Jolly head flying ses flybarless rotor head Blade linkage tea- sion new Legend chopper Note tures delta hinge midway up rotor shaft now has flybar-type rotor head affecting rotor system Thats good means quicker response input types short its efficient system power available main rotor penalties Remember said quicker response put also includes outside influences like wind gusts other atmospheric stimuli Re member flybar tended dampen out effects Without flybar things controlling system servos herent stability blades As know rotor blades have center-of-gravity aft point blade rotates pitch makes blades lag tend buzz generally unsta ble pitch going depend stability blade must find some method stabilize can accomplished adding ballast leading edge blade thereby bringing its center-of-gravity pivot point closer same location benefit twofold added weight also improves blade momentum dur ing autorotation greater mass further increases job cyclic servos means flybar less model must use strongest servos best gear trains ensure precise input maximum control power course true Helicoptersbut important case So much physical differences Lets look differences practice 60 Model Aviation Radio Conoi Helicopters Larry Jolly 5501 W Como Santa ADa CA 92703 GMP Legend Helicopter doing what does bestcruising skies column Larry says Legend good acrobatic machine too shot bird inver ted flight substantiates claim First let make blanket statement GMP Legend stable natural-feeling flybarless model have ever flown first thing will notice lift off flybar less machine will need hold stick some position wait see model respond following rate extremely fast making control response instantaneous means will have get used ship responds little faster Instead holding put will learn flybarless machine best controlled small numerous control ap plications rather single heavy held long time Legends case very difficult tell equipped flybar its hov ering Legend has peculiarity hoverthe tail tends want drop fast Pi rouettes performed major problem easily controlled little bit forward cyclic typical behavior rotor heads having minimal dampening Once forward flight will notice Legend requires forward cyclic maintain level flight because Legend does exhibit coupling fore aft cyclic collective put means fast forward flight high power input will show up ten dency climbas loop Conversely sud den negative collective pitch command will cause tendency nose drop bad can fact enhance aerobatic capabilities positive maneuvers instance execut ing Split-S ship will tend want tighten radius loop due phenomenon maneuver really bears watch ing autorotation up 50 negative pitch much negative low-rate foreand-aft cyclic could unnerve yourself sloppy entry autorotation means yank power quickly going full negative collective pitch ship will nose down will give impression wanting tuck under showing response Up elevator way out position come up slightly collective pitch use aft cy clic Utilizing collective pitch will give instantane ous recovery have found Legend capable flybarless tuck unless high degrees nega tive pitch used rash entry attempted Thats Thats difference Legend flybarless machine clean design low weight high power combination tough beat aerobatic excellence Legend also home either high low revs obviously performs better wound up little GMP now has options available fine tune Legends capabilities time per mits Ill test Legend conventional rotor head report its characteristics mean time have fun tearing up sky Leg end Theres nothing like BCNU June 1989 61 FLYING NEAR Al RPORTS BE CAREFUL PROTECT YOUR RIGHT TO FLY Safe Flying No Accident
Edition: Model Aviation - 1989/06
Page Numbers: 60, 61
LAST MONTH took look Gorham Model Products new Legend flybarless-rotor-head sport/competition machine recall really liked Legends aerobatic prowess excep tional autorotation capabilities pick up left off Ive now got experience Legendabout five gal lons hard flyings worth Nothing has cracked fallen off have found few things watch out First keep tail rotor drive belt tight Its dif ficult describe tight makes right Its basically set properly cant rotate main rotor restraining tail rotor course must no excessive drag sys tem run tail rotor belt too loose could wear out front plastic drive pinion occurs recourse replace pin Ion symptom loose belt glitchy tail hover rapid collective pitch movements applied almost looks like ship has gyro rate too sensitive resulting hunting yaw other thing look Teflon washers collective pitch pivot will eventu ally wear will need replaced restore units original slop-free condition Last month mentioned flybarless models fly little differently used fact will gist report Flybarless models seem get perpetual bad rap Horizon won Nats general consensus Horizon rea sonable machine Hubert Bitner won de spite lack flybar So whats difference between ship has flybar flybarless obvious answer ybar Just what steel rod its two little pad dles doing us Basically Hiller flybar al lows us feed control inputs flybar turn controls main rotor blades done disturbing rotor disc flybar re turns its neutral setting forces main ro tor blades feather neutral position So effect flybar adds autostabilization ro tor head flybar also goes action rotor disc acted upon outside force such gust wind As know Hiller sys tems superstablebut also tend slow reacting control input response rate can course increased adding mixer input directly blades known Bell/Hiller system modem flybar systems based generally accepted norm basic modifications being make head tighter looser depending method dampening So what happens throw flybar away Well first thing decrease drag Note Larrys Legend equipped Larry Chris Jolly head flying ses flybarless rotor head Blade linkage tea- sion new Legend chopper Note tures delta hinge midway up rotor shaft now has flybar-type rotor head affecting rotor system Thats good means quicker response input types short its efficient system power available main rotor penalties Remember said quicker response put also includes outside influences like wind gusts other atmospheric stimuli Re member flybar tended dampen out effects Without flybar things controlling system servos herent stability blades As know rotor blades have center-of-gravity aft point blade rotates pitch makes blades lag tend buzz generally unsta ble pitch going depend stability blade must find some method stabilize can accomplished adding ballast leading edge blade thereby bringing its center-of-gravity pivot point closer same location benefit twofold added weight also improves blade momentum dur ing autorotation greater mass further increases job cyclic servos means flybar less model must use strongest servos best gear trains ensure precise input maximum control power course true Helicoptersbut important case So much physical differences Lets look differences practice 60 Model Aviation Radio Conoi Helicopters Larry Jolly 5501 W Como Santa ADa CA 92703 GMP Legend Helicopter doing what does bestcruising skies column Larry says Legend good acrobatic machine too shot bird inver ted flight substantiates claim First let make blanket statement GMP Legend stable natural-feeling flybarless model have ever flown first thing will notice lift off flybar less machine will need hold stick some position wait see model respond following rate extremely fast making control response instantaneous means will have get used ship responds little faster Instead holding put will learn flybarless machine best controlled small numerous control ap plications rather single heavy held long time Legends case very difficult tell equipped flybar its hov ering Legend has peculiarity hoverthe tail tends want drop fast Pi rouettes performed major problem easily controlled little bit forward cyclic typical behavior rotor heads having minimal dampening Once forward flight will notice Legend requires forward cyclic maintain level flight because Legend does exhibit coupling fore aft cyclic collective put means fast forward flight high power input will show up ten dency climbas loop Conversely sud den negative collective pitch command will cause tendency nose drop bad can fact enhance aerobatic capabilities positive maneuvers instance execut ing Split-S ship will tend want tighten radius loop due phenomenon maneuver really bears watch ing autorotation up 50 negative pitch much negative low-rate foreand-aft cyclic could unnerve yourself sloppy entry autorotation means yank power quickly going full negative collective pitch ship will nose down will give impression wanting tuck under showing response Up elevator way out position come up slightly collective pitch use aft cy clic Utilizing collective pitch will give instantane ous recovery have found Legend capable flybarless tuck unless high degrees nega tive pitch used rash entry attempted Thats Thats difference Legend flybarless machine clean design low weight high power combination tough beat aerobatic excellence Legend also home either high low revs obviously performs better wound up little GMP now has options available fine tune Legends capabilities time per mits Ill test Legend conventional rotor head report its characteristics mean time have fun tearing up sky Leg end Theres nothing like BCNU June 1989 61 FLYING NEAR Al RPORTS BE CAREFUL PROTECT YOUR RIGHT TO FLY Safe Flying No Accident