Control Line: Aerobatics

SEVERAL times over years Ive suggested use sealed hinge lines refined trimming technique various times suggested possible cure such diverse trim diseases unequal inside outside turns hunting un wanted roiling tendencies turns assorted other undesirable characteristics Events last several months have rein forced conviction indisputable value sealed hinge lines Quite frankly Im now pre pared state sealed hinge lines should routine part flight preparation Control Line model purpose life performing aerobatics degree predictability precision Heres Ive decided such strong posi tion Over last few years Ive privileged fly quite number OPPa Other Peoples Planes case youre wondering No dont mean top-gun Pro-Stunt killer ships such Casales Spectrums Walkers Bad News Im talking about less refined efforts beginner advanced pilots trying climb Michael Hawk Sig Banshee inspiration months column seal ing hinge line gaps look closely can see %-in gaps flap eleva tor hinge lines made plane almost unflyable Once sealed now flies just fine ladder using off-the-shelf hardware such Ban shees Twisters etc opportunity has occurred several Stunt clinics Ive asked participate great idea way youve got happy combination en thusiastic newcomers cooperative experts area cases Ive pilots tell could fly well ships could competitive Because appear have fulfilled physical requirements good Stunter since lack experience truly well-trimmed Stunt ship logically sume plane fine problem nut holding handle Surprisingly Ive flown ships Ive discovered very often reverse true pilots perfectly capable flying better being held back lim ited capabilities ships major ity cases performance ships could helped measurably sealing hinge line least elevatorand ofttimes flaps well Lets take look specific example problem examine what happening sealing cure finally primer actu ally doing job classicand graphicexample effects sealing presented gung-ho young pi lot Gilroy CA Michael Hawk watched Michael fight Sig Banshee through couple attempted patterns frankly too impressed Although everything looked pretty good preflight check airplane possibly pilot just wasnt cutting air seminar April finally chance Continued page 155 MX FRON SSRWS SEOTOI PLASTIc TN SURFAC HINILDE SERLS E1INI1TE PRESSIME LEED 1110111 FIGURE J ON SElLOW SEAL NIHIELIIEOW SEAL RHOST IhINKLETT DR DISRO uioutn RE NO HORE jHYLtII hinGEs TMN tIlE INCH FRaNWBLl~J2TYPICAL TIP CF NOJAGIE SlACa lYPIcAL L0VT IllS F HINGELDIE IP ALS Fancher has computer printer working overtime lately Careful study drawings coupled study written statements column will help make next Stunter better planeor improve present dog Ted finds fledgling Stunt pilots being hindered aspirations planes dont fly well recommends newly built CLPA planes have hinge line gap seals installed before ever flown makes less unknown problem area refine plane tuned best performance Read heed 70 Model Aviation Conoi Line Aerobatics Ted Fancher 159 Flying Cloud Isle Foster City CA 94404 front end Don McClaves new Patternmaster shows latest technology Tonguetype muffler Pro-Stunt Bolly 3-blade prop Tru-Turn spinner Tom Lay modif led Supertigre 60 sits inside cowl WPER AIR AM LD AIR 1RA EOIAL DISTANCES THuS NO SPEED OR PRESSI DDFNC AM TtEREFORE ND LIFT AIRSTRb. CONTROL S1RAII NEIJTRI PIISSIElE EJNFIGURE FIGURE II 1~:rtFPER AIR TRAJELS FUUTH RESULTING IN HIGhER SPEED AXUSTREAN .N6 LIIUER PRESSURE AWE N N N AF HIllIER PRESSURE RE5LT WHTRII SIlFACE OOIECTEDJ PISSIII DIFFtJENIIA LOWN AIR TRAWLS SIORTE DISTANEE TillS tINIER SPEED F TIIIfl~GAP KtIEN FIXED IIDiJASLE CONTROL LUUIE LLSURFACES ALLINS NIGH PRESSURE AIR TO SLEEP rhUOUSI REDUCE PRESStIlE DIF FEWITIIL SETIWI IFFER LOISS SURFAcES LOT M CONtROL EFFECt IWNESS AS RESULT HINDf LIFT LOST VIE TO PRESSURE 611EV 1110111 GATOR RIC PRODUCTS TIGER TAIL 4S DELUX ALL BALSA KIT An new Tiger Tail 120 four strokes piped 60 two strokes beautiful performer competition just showing offi balsa kit machined wood parts complete hardware package includes plug-in adjustable stab parts new wing mounts Wing Span -72 inWing Area 860 sq Complete Delux Kit515995 TRANSMITTER CASE An inexpensive rugged molded case protest expensive transmitter both two stick single stick transmitters Black leather grain aluminum trim locking clasp S 1995 MV-I TYPHOON New F3A competition Big beautiful flyer balsa construction plug-In wings 120 four stroke 60 two stroke power Plans-two sheets 51495 Fiberglass cowl $1895 Clear butyrate canopy. S 995 OTHER PLANS Tiger Tail 4S-two sheets 120 four strokes51495 TAR baby 120 four strokesS 2195 Alley Kat 40 size trainer sportS 895 Gator Flea 40 size sportS 895 Bobcat 40 size sportS 895 GATOR SOFT MOUNTS COMPLETE SOFT MOUNTS INCLUDES AU HARDWARE Optimized lowest vibration transmission airframe minimizing engine shake Available YS-60 OS60 SOFT MOUNT COMPO 4-lug Mounting Plateb black anodized Undrilled 5595 DrilledforYS-600r05-60 5695 Rubber Iso-Mounts SIB diameter x 112 long wIth 832 female end 832 s 112 male other end Specify soft SO durometeryellowj firm 60 durometer-purple Each. $3OOPkg0f4$995 feather Ilte glass cloth 7 ozsq yd est weave Fastest Filling est Finished Weight Big 3 Sq Yard Pkg Detailed Instructions- 5895 Include $2 SOiltem UPS esidents Add 6% Sales Tax GATOR RIC PRODUCTS 3713 Pompano Dr acola FL 32514 476-8639 CL Scale/Boss Continued page 151 Foster Parkway Fort Wayne IN 468061730 might also note Smithsonian Books Drawings has released newly revised edition National Air Space Mu seum CDB Bryan 300 photos book takes inside worlds visited aviation mu seums price $4995 $4496 museum members can ordered call ing 1-800-678-2677 Reminder From time time receive let ters ask whether Radio Control can used CL Scale models model basically controlled twoor three-line system other functions such flaps gear retraction dropping bombs fuel tanks etc controlled radio equipment recently asked Ronald Macknet Yulee FL may technical rea son flight operations other func tions CL models cant radio con trolled AMA rule book forbids use radio transmission prohibited paragraph 2 General Control Line rules page 23 1988-89 AMA Compe tition Regulations Book states Control Line model aircraft flown steel wire lines metal lines equivalent strength tached model manner providing aerodynamic control models eleva tion through manipulation control sur faces during flight Such manipulation control surfaces may accomplished either mechanical means electrical im pulses transmitted through lines use mechanical well electri cal impulse systems has previously ex plored column months throttle stop adjuster example have ideas along line send use column Im sure others would interested Miscellaneous While rummaging through local automobile supply store recently came across interesting item want quick way simulating access mainte nance panels Scale models might want try Its called Metal Mend Tape available through Trimbrite Prod ucts Spartan Plastics Inc PO Box 67 Holt MI 48842 Metal Mend Tape self-adhesive alumi num comes 3-in 5-ft roll about 1 sq ft material about 004 thick roll paper back ing weighs about 1A oz semibright sheen Application adhesion alumi num works best surface com pletely smooth free imperfections possible Care must exercised applying material can easily wrinkled Once place can worked smoothed tools made rounded soft balsa sticks soft cloth using hand pressure application best fairly flat sur faces material can stretched slightly worked around moderate curves After its adhered surface can scored simulated dzus fasteners riv ets etc painting desired very light sanding surface 400 500 grit wet dry paper will help adhesion paint might also note Trimbrite Prod ucts has large selection pinstripe tape both single multistripe styles Primarily designed use automobiles can also used dress up Sunday flier Publicizing clubs CL Scale activities should go beyond own club newslet ter Quite often see reports did what local club Scale meet could report words results would much interesting see pictures some models flown con tinually read newsletters know new models being brought out time share read ers Lets keep CL Scale alive moving forward Please send ideas comments contest ac tivity reports especially photos CL Scale activity address very top column CL Aerobatics/Fancher Continued page 70 fly Michaels ship make long story short nearly crashed ship turned half heartedly inside nearly impossible turn outside Ninety-degree round loops werent fault poor piloting airplane simply would turn tighter After surviving flight examined Ban shee closely standard answer lack corner lack turn case move CU aft Experience told ever Mikes CG plenty far back moving would cause harm good plenty control movement pushrod properly supported fairleads line tension adequate ensure full deflection controlsyet ship still didnt turn solution problem seal el evator hinge line Michael installed con trols using Klett/Du-Bro-style pinned nylon hinges pinned part hinges about %2-in diameter Unless recess made control surface during construction result gap %2 1/8 between movable fixed parts surface gap caused Banshee turn like trainer rather like Stunt ship advertised Once sealed gap ship took new life perfectly capable rule-book-size maneuvers square corners nicely balanced rates turn both inside outside Lets take look unscientific birdmen believe flap elevator performs its function deflecting airflow over angle surface up will deflect airflow push surface away thus making ship turn nitro breath What actually takes place change shape total control surface airfoil See Fig ures II neutral airfoil symmetri cal air pressure above below sur face equal movable surface de flected either up down have created cambered airfoil Because airflow over convex top airfoil must move farther concave bottom must move faster order get trailing edge same time air flowing over opposite side faster flow reduces pressure top surface pressure bottom ac tually increases fair amount differential pressure produces lift direction lowAugust 1989 155 esic The BEETLE SUPER DELUE KIT $40 Th BEETLE designed Y Aluba Top Japanese Pilot FAI AMA EPOXY GLASS FUSELAGE & FOAM CORE WING Pius fochmologioalty advanced foIfeLOaWfau PAlTERN TEK info aMEwF3AawModt ADDRESS 34k TURTLE CREEK CT SAN JOSE CA p5125 PAlTERN TEKTELEPHONE4O82980311 FAX 4082986538 pressure side lift creates turning moment force around center-of-gravity increas es angle attack wing increas es lift allows aircraft loop etc Ob viously greater difference pressure greater force applied about CG faster ship will change direction Heres sealing hinge line comes play Remember 342-in gap between stab elevator caused diameter hinge gap occurs almost exactly point difference air pressure tween top bottom surface great est As know nature abhors vacuum high-pressure air can get low-pressure side know will ght through hinge line gap See Figure III degree pressure differential minimized flowthrough control effectiveness diminished larger gap effectiveness will lost Michaels case gap got little larger dur ing outside maneuvers ship notice ably less responsive outside inside seal ing gap cured two problems First air plane turned much better overall because tail powerful both inside outside Sec ond because tail equally powerful up down response control inputs became satis fyingly consistent no longer merely flick wrist insides yank worth outsides ship turned equally well both directions Most important also capable flying recognizable AMA pattern task well beyond its previous capabilities Once tail working well further weakness showed up During hard corners wing would occasionally stall evidence stall sort double turn last cor ner triangle ship would turn 9Q0 Free flight Kits Supplies Rubber er Power Kits Scale Old Timer Too Co2 Electric Motors Rubber Tissue Cox Parts Rubber Accessories Winding Hooks Timers Nitrate Dope CATALOGUE $200 CAMPBELLS CUSTOM KITS PO BOX 5996 LAKE WORTh FL 33466-5996 156 Model Aviation suddenly stop turning momentarily complete last part corner cured tendency sealing gap flap hinge line Now wing able produce amount lift required corner stalling stall way result two fac tors First pressure flow-through hinge gap caused premature disruption airflow over top wing caused stall well before wing reached its normal critical stalling angle attack Second Michael stalled outermost hinges full three inches ends flaps themselves Un der load flaps almost certainly bent fluttered beyond hinge thus disrupted airflow make rule never have inch flap beyond outermost hinge So should positive effects sealing obvi ous absence negative aspects fi nally brought conclusion sealed hinge lines should accepted practice beginners advanced pilots brand-new ship will eliminate outset num ber possible trim problems before raise ugly little heads retrofitting already trimmed out airplane very worst thing could happen would would become responsive control input too quick controls however isnt really negative merely some thing can trimmed out final anal ysis can make ship better performer instance ship seemed little light lines before sealing could now afford move CG forward bit sac rificing cornering ability would gain line LARRY JOLLY KITS Now Stock Pantera 100 span Great contest Plane11995 Cheetah 112 span AIleron contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Fllnger 59 Span great hand launch plane3495 CA les add 7% Tax $395 S&H Complete Catalog 5300 0 tension also bit additional stability advantage made Nats winner out Intimi dation 1982 other hand like CG line tension adequate better can still improve performance reducing spacing handle slow down per ceived response rate case net effect identical feel same rate response airplane will operating efficiently since smaller control deflections will required rate response Now youre convinced sealing good idea whats best way go about Al though several types hinges market automatically seal hinge line installed really designed RC planes dont recommend Control Line use Without exception types hinges introduce some stiffness controls therefore appropriate use RC constant force available servo minor stiffness little consequence since line tension variable Stunt ship stiffness simply acceptable Ive included some sketches way seal controls pretty much selfexplanatory few hints Materials Until recently Ive used strips Fas cal clear sticky Mylar Combat fliers use covering works well free stiffness does come loose after period time very difficult remove entirely re placement Ive recently learned about Scotch Brand Plastic Tape specifically plastic just well-known Magic Mending Tape goes aggressively seems seal well yet can removed easily leaving gooey residue lasts appears much better choice seals Installation prefer install seals tween hinges seal over hinge itself tape sticks hinge causes stiffness Always install seal bottom aesthetic reasons Hold control fully deflected tape rubberband installing seal no tension caused seal tween fixed movable surfaces seal should wide enough extend onto flat part control surfaces half-inch good adhesion Oil will work tape opposite side seal loosens will hinge line outward Inspect seals regularly ensure gap itself remains sealed Replace seals necessary responding advrtlaera mention read about ModelAviatlon