Radio Control: Scale Aerobatics

RADIO CONTROL SCALE AEROBATICS Since last column Ive received three phone calls pilots frustrated airplanes two Giant Scale Aerobatics models other Pattern aircraft pilots convinced airplanes either designed poorly set up incorrectly because problems experiencing maneuver Stall Turn specifically pivot top Stall Turn Stall Turn Hammerhead same maneuver Stall Turn can really make pilot question his/her abilities aircraft Through years common complaint hear aspiring Aerobatics pilots involves airplanes wont Stall Turn cases pilot local meet field he/she can show offending aircraft complete attempts maneuver either flop fly around big arc sky usual outcome flight demonstrations pilot hands transmitter disgust whereupon few Stall Turns both directions land Sometimes pilot relieved see airplane behaving well other times visibly annoyed being able fly maneuver model guess its desirable hear someone agree equipment problem rather demonstrating perhaps its lack technique Its exceedingly rare find fourchannel airplane cannot decent Stall Turn dont recall finding sport Aerobatics model couldnt maneuver quite nicely setup design issues affect Stall Turn Airplanes very small rudder area will difficult may require install larger rudder Airplanes very low amounts rudder deflection will have problems thats simple rectify servo travel output arm control horn changes Its also possible center gravity CG affect Stall Turn experience has airplane flies well other maneuvers has CG location suitable performing maneuver therefore CG usually big factor Assuming CG reasonably located rudder adequate size throws 30- 350 full stick what else causes problems pivot portion Stall Turn Timing airflow definition pivot top Stall Turn performed airplane has almost halted its forward speed vertical line Thus critical factor timing rudder input put rudder too early airplane will fly arc top rather pivot subject various degrees downgrade complete arc will earn zero looks bad semi-pivot onewingspan wide earns smaller downgrade Ideally rudder will input just before model reaches zero airspeed Wait too longespecially larger modelsand likely enter short tail slide will develop flop results another zero~ score Stall Turn can really make pilot question his/her abilities aircra ft plus pals may snicker dont care about scores just think efforts learning Stall Turn correct way Now its time look airflow important factor pivot also commonly overlooked Without adequate air moving over rudder cannot produce enough yawing power make airplane pivot hope answer airflow problem obvious need ensure propeller moving enough air over rudder make effective Since forward speed almost nil enough airflow rudder effective air propeller some airplanes will easy because very large powerful rudders coupled large propellers produce fair amount thrust idle settings case airplanes proper timing alone can result picture-perfect pivot airplanes way reliably achieve perfect pivot have some power applied kick rudder will allow good airflow over rudder let its job swinging tail around few ways ensure have adequate power settings pivot method activate idleup function some kind can used either increase idle speed just Stall Turns decrease low-stick idle speed two maneuvers may require minimum tick-over spins landing Thus normal idle can set slightly higher thrust output Either option works long always know what idle-up functions have active disadvantage must flip switch keep track idle setting have active method use throttle stick primary control doesnt require ahy programming switch-flipping infinitely variable However still two basic options Stall Turn flown method Which option used depends mostly aircraft performance personal preference airplane unlimited vertical performance reduce throttle smoothly idle airplane approaches height want perform pivot As airplane stops smoothly input small amount throttle kick full rudder As nose passes 900 rotation can reduce throttle back idle since airplanes need very little power fly straight down approach allows precise control over aspects positioning performing pivot drawback throttle rudder must input correctly its slightly difficult master heavier draggier lessoverpowered models might simpler leave throttle full perform pivot airplane slows stop its own biggest drawback approach wait splitsecond too long apply rudder model might start tail-slide theres nothing can about since have already applied full throttle advantage real variable timing rudder input So might simpler process youre just learning having problems pivot try adding about 25% throttle same time hit rudder airplane slows almost stop causes airplane climb pivots add slightly less power next time have airplane vertical wil/ able find combination forward speed throttle setting timing rudder input will work problem might have tendency airplane roll pivots usually problem sport-trainer-type models lot dihedral Either mix roll coupling out learn input aileron 148 Model Aviation put rudder As release rudder following pivot release ailerons same time notes Stall Turn start out same quarterloop horizontal vertical flight vertical line established may may contain roll some fraction roll top maneuver pivot vertical down line again may include some portion roll recovery level flight Three problem areas inherent quarter-loop transition horizontal vertical flight basic non-rolling Stall Turn first wings need level quarter-loop initiated else airplane will transition true vertical line Second vertical line may need corrected wind conditions See former article AMA Competition Regulations IMAC [International Miniature Acrobatic Club] rules regarding wind correcting vertical lines Third performance quarter-loop needs constant radius sized fit maneuver performance aircraft novice tendency pull too hard making quarter-loop smaller optimum smooth pull will cause fewer problems give time subtle corrections quarter-loop provides numerous challenges pilot wants perfect Stall Turn pilots can work problems portion maneuver eventually get good results dont get calls quarter-loop because its somewhat easier see problems what solutions needed Im out room Let know like sort column Until next time have fun fly safely E Caclus Wren Rd Scolladale AZ 85253 Teie02-948-5798 998-7005 * * Long Engine Life * * Use BRU LINE Air Cleaner Completely Fuel Proof Nylon Rubber Parts Cat No 102 Air Cleaner Coarse $299 Cat No 202 Air Cleaner Fine $299 Replacement Inserts Cat No 104 PJ2 Inserts Coarse $239 Cat No 204 Pkl2 Inserts Fine $239 FITS MOST ENGINES 25and UP SEE YOUR LOCAL HOBBY DEALER IF UNAVAILABLE LOCALLY SEND TO Bru Line Industries Inc pa Box3786 CenterLee Mchgan480l5 Add $250 sh pp ng M ch gan es dents add 4% 85 es tax December1998 149 CHL % XJR VcrLTAEE CHECK IrON-sIr titlE WITH 8snaddg Mounts fuselage side cockpit easily seen place Plugs unused receiver channel Moving servos shows loaded battery voltage Helicopter version available enclosed plastic case 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