Radio Control: Helicopters

RADIO CONTROL HELICOPTERS U 1I1 ri Last month talked about pitch curves what they formed gave formula easy way set up computer radio give straightline curve~ once have determined end points Now Ill take another look pitch curvesinitial setup adjustments tell what changes needed after have flown helicopter important aspects setting up pitch curve making sure basic mechanical setup helicopter correct Although helicopters same virtually have things common would surprised following does apply helicopter mean basic setup pushrods bellcranks control horns should set up per helicopter instruction manual should rather easy check just looking helicopter radio installed servos neutral positions make sure servo arms perpendicular puslirods Notice didnt say servo arm should 900 servo body because radio installations servos themselves mounted offcenter position aligned helicopter frame Once servo arm correct check make sure pushrod attached correct distance center servo arm instructions specify servo arm distance initial setting make helicopter feel right its initial flights Remember farther out servo arm pushrod attached sensitive controls will bewhich its good idea follow manufacturers instructions first few flights can make changes suit flying style personal feel Check other end pushrod What attached arm its perpendicular position centered per instructions arm centered correctly controls will have effect direction other collective will feel same changes positive negative Although am referring collective pitch control procedure applies pushrods ensure correct feel movement stick extremes Disconnect pushrod servo move back forth servo would binding movement would cause servo work harder should Can get full throw positive negative directions Once convinced mechanical setup correct free reattach pushrod servo turn radio travel should set 100% both directions servo arm should move quickly freely equally both directions Place pitch gauge main rotor blade see what get collective pitch maximum minimum collective points instruction manuals give reference collective pitch range particular helicopter dont have numbers go following have proved good throughout years general flying will ballpark initial rhey initial settings get off the ground can make adjustments suit flying style performance helicopter flights High id ow rovides total pitch window 120 ..30 9 0 center being 30 means will have linear match collective pitch movement collective control stick However just learning hovering process believe above pitch range too large will make collective pitch too sensitive until get used 90 maximum pitch will allow helicopter climb quite rapidly 30 will allow helicopter screw itself ground let Therefore conservative collective pitch setting novice would High id ow 0 window makes collective stick half sensitive first example collective pitch setting will have hovering above half-stick will limit amount climb can get helicopter since excess altitude friend learning hover also eliminating negative collective pitch could damage helicopter during panic landing collective pitch settings should set mechanicallywithout use computer functions radio An easy way to check collective pitch window range noting pitch full bottom collective stick positions range what want 120 first example 60 second reduce moving pushrod closer center servo increase moving pushrod further out arm couple tries should able find position servo arm will provide desired window Once window set check maximum minimum collective pitch readings see desired arent dont adjust pushrod servo since already made sure set up properly other arms bellcranks Make adjustment rotor head usually pushrod going swashplate mixing arm Its easy giving full collective radio making adjustment until desired maximum cotlective desired Now have maximum collective desire window has already set minimum collective must also desired initial settings nothing ballpark numbers No pitch gauge can accurately measure collective pitch within degree because much depends position swashplate flybar level pitch gauge readings will slightly off has never really concerned initial settings get off ground can make adjustments suit flying style performance helicopter After making initial pitch adjustments consider helicopter performs making max climb rapid descent rotor speed starts decay during max climb engine sounds its lugging too much pitch top end no matter what pitch gauge indicates helicopter descends too rapid rate during rapid descent too much negative collective will take some experimenting during few flights get settings like try make changes mechanically adjusting pushrods rather using computer functions radio Once basic setup like can use computer functions idle up two etc fine-tune helicopter desire Let know technique works share other readers other techniques have 4November 1997 107