Radio Control: Aerobatics

RADIO CONTROL AEROBATICS WHEN FIRST became involved Pattern trim Pattern model favorite topic Aerobatics columnists Computerized radio mixing yet arrive complicated convoluted prescriptions confidently offered up involved lot shimming bending cutting twisting heating epoxying glassing re-epoxying reglassing Trimming cookbooks charts filled data about what much to what component produced reverently handed around like ancient scrolls come think some may have ancient scrolls Some charts still use today occasionally still useful cut-and-try-your-best-guess labor involved monumental timeconsuming wasnt worst worst constantly gravely assured process essentially circularwithout discernible end Most competitors day myself included bought tail-inmouth trim-until-you-drop philosophy wholesale lots seemed like good idea time Thankfully sticky messy legacy has passed pages Pattern history no longer routinely saw wings half cut stabs out completed models reposition bend wing tubes over bumper adjust dihedral Thrustlines still get shimmed battery packs still moved fore aft balance razor-saw-and-epoxy trimming approach has largely replaced index-finger-and-touchscreen method dedicated masochists still weep good old days Im Unfortunately cornerstone old method still stands like mossy ruin like good mossy old ruins its way idea trimming something keep doing forever because its never quite done still being solemnly handed down sort like heirloom watch no longer keeps good time analogy isnt quite apt watch never did keep good time Trimming ad infinitum may have popular dictum given grossly inexact methods some designs use time sometimes unavoidable task never good idea Constant trimming uses up scarce practice time huge chunks occupies brain cells could better employed figuring out really complicated stufflike center maneuvers four seems like such popular number judges fly Far too often trimming used substitute practiceand convenient excuse poor performance dont mean its good idea never trim never check trim fly out-of-trim model just mean constant tinker tinker tinker approach see much counterproductive Ive seen people actually change trim settings between rounds contestseven Nats New carbon-steel step-reamers Indy RC Removable handles allow reamers chucked drill press process few grams wont make much difference build left wing panel weighs three four ounces right doesnt take Nostradamus predict future problems Rigging major part trimming Before fly check make sure wing tailplane incidence angles stated plans engine thrust angles called Most designs call wing set slightly positive stabilizer egree usual will usually some right thrustup three degrees some designsand perhaps little downthrust well designer called put likely knows about model Oa calm day fly model well broken-in well-adjusted engine using prop plan compete Set rndder dead amidships ground leave Trim level flight full power land Check position control surfaces dont trail exactly level have capability adjustable wings stab adjust direction indicated surface Trimming shouldnt long involved mysterious complicated ordeal something very wrong method model both Good trimming starts bench during building process Straight wellbuilt airplanes easier trim Setup major part trimming Geometrically proper control hook-ups properly aligned sealed control surfaces will wipe out potential trim problems before occur Balancing major part trimming important trim adjustment Center Gravity accurately Balance Point location modern Pattern designs airfoils 33 35% MAC Mean Aerodynamic Chord just about right Any decent basic text aerodynamics can show figure point highly recommend Model Aircraft Aerodynamics Martin Simons Its well-known reference hobby dealer likely already has hand can easily order designer has expressed preference plans put BP case figure point set point leave alone Make first thing set change nothing else works totally convinced root problem change prepare start over again reason BP basic affects almost other adjustment might make Constantly moving BP can often does mean constantly adjusting everything else Down twisting road lies great state Confusion Lateral balancing major part trimming Lateral static balancing means making sure left side airplane weighs same right side also starts during building 86 Model Aviation 4Piarun Wing Adjusters Unique Design Development Low profile strong very lightonly 45 grams deflection fly again Repeat until surfaces trail exactly Note up elevator means add positive incidence wing negative stab vice versa down elevator find much better add subtract wing incidence Fly model upright inverted power power off should take just bit down elevator hold inverted power slightly power comes off takes think should land make note Use pencil notebook purpose Fly model level full power smoothly pull vertical up line correcting several times possible directly away yourself ensure wings level model drifts left right consistently land make another note Fly vertical down lines power off model should drop straight least 100 meters pulls canopy tucks belly make note Fly vertical up lines center model pulls consistently canopy belly make note Fly model level cut power suddenly Watch significant pitch up down slight decay line after few meters normal same 450 up line 450 bank Make note Kip Jackson Holds Dennis Cone starts Bully 120 Dennis Cone shows oft belly Meridian Four-foot long powered Meridian 860 Verticals model-rocket type exhaust system totally enclosed Consider notes before making thrust adjustments because tests interconnected defect maladjustment may cause multiple sins instance power-off down lines fine very likely incidence angles correct model trimmed well level flight model pulls belly during vertical ups too much downthrust likely answerespecially saw nose lift up closed throttle last test above Also aware single symptom may have several different causes instance need excessive downelevator input powered inverted flight might symptom nose-heavy condition might also insufficient downthrust accidental upthrust insufficient down-elevator travel performing test sequence looking results before making changes real problem can usually isolated much trouble thrust incidence adjustments complete fly model both knife-edges Use just enough top rudder hold level flight look tendency roll out proverse couple roll under inverse couple Land use mixing dial out rolling tendency knife-edges Dont worry about pitching point just correct roll wing rolls off edge no longer unloaded produces liftand lift vector produces pitch Without correcting roll first impossible isolate pitch correction model no longer rollcouples check both knife-edges pitching model does everything else well point can safely mix out small amount pitching either direction canopy belly either knife edge isnt uncommon model pitch little knife edge pitch small amount opposite directions both knife edges about trimmed 98% Pattern models ever got before computer radios Leave whatever mixing required timesthe same forces causing pitch knife-edge action stall turns level flight slide type rudder corrections model pitches good deal same direction both knife edges have basic incidence and/or balance problem corrector likely simply design stabilizer located poor position relative wing too high stab location can cause pitch belly etc start proven design follow steps outlined make adjustment time at-the-field trimming process will surprisingly / SCALE /AIRcj DOCUME IAISAS Antiques Military Civilian Helicopters Sailplanes OUi have worlds largest aircraft documentation collection 6400 different Full color photo studies 1905-1996 Q 35000 3-view line drawings 1 997 Catalog/Guide 200 pages Canada/Mexico $1000 Bob Banka Only $8w Overseas $15 00 Scale Model Research 3114 Yukon Avenue a Mesa CA 92626 714 979-8058 Look us net http//imt net/ims/scalehtml September 1997 89 se Con n k periloats other planes 6 dontdelaySeethemat D & J ELECTRONICS Marigold St NW Hartville OH 44632 1236330-877-1445 Service & Repairs Most Radio Control Systems Utilizing Calibrated Test Equipment & Spectrum Analyzers Endors0d AMAi RCMA Sticker Station #105 Futaba Airtronics JR Ace HiTec Tower Cirrus World Engines & WE USE GENUINE FACTORY REPLACEMENT PARTS Complete 1991 Narrow Banding & Upgrades RCD / HITEC R/C DEALER FCC Licensed Speed Control Repairs Quality Service Fast Turn Around Shipping & Insurance Extra UPS ailCODs Z Visit home page http//wwwdnjeIectronicsCofl1 Email david@dnIelectronicscom jayne@dnielectronicS AMA #256123ARRLWB8YSQ FEATHER CUT creates new standard ease accuracy cutting white blue foam wing cores ds offl Precise single wire tracking concert micro-adjustable balance weights guided exclusive three-point tracking system guarantees ripple-free surfaces No trailing edge burn-out common two wire systems Couple FEATHER CUT Tekoas THERMAL GENERATOR fool proof temperature control youll Pro. first time out Cuts straight taper wings fins stabilizers matically ts tape edge workbench dining table stores its own heavy duty mailing tube lete kit anodized plated components no hardware store trips ructions include cutting first wing making templates e 28 Fold Bow 40 52 Available Power supply required Guaranteed out perform rest Simply bestl TEKOA THE CENTER OF DESIGN 49380 SKYHARBOR WAY AGUANGA CA 92536 FEATHER CUT $14950 S & H THERMAL GENERATOR Power Supply $11950 S & H short painless uncomplicated may have shim thrustline slightly Most modern designs will take few beeps tweeps knife-edge mixing may have dial out small amount inverse proverse roll couple rest will setting up rates exponential snap rolls like single afternoon session should need followed occasional recheck odd calm day make sure adjustments holding best trimming advice ever got Know quit airplanes crooked Orville Wilbur couldnt straighten out Sell can afford burn worth mental health others learn settle best compromise can work out reasonable 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