1/2A Streaker

Flown Junior Class Pro winner holder DESIGNED AND BUILT during winter 1970/7 1 mainly because Barry wanted build fly airplane own rather just duplicate brother Bruces 1970 Nationals-winning Red Baron original Streaker still going strong Its latest achievement first official /2A Profile Proto flight national record over 90 miles per hour 9180 mph 9/15/74 using coupledlines emphasize use coupled-lines because Control Line Contest Board has since prohibited use event thereby voided record agree very much decision pro hibit use /2A Profile Proto event other events normally flown two-lines feel coupled-lines have unfairly maligned C/L columnists wrote negatively about did take time trouble experiment did As matter fact 9180 mph record really just side result experi mentation want take oppor tunity get 2-worth expressed subject Having heard FAI use coupledlines also called tied funny trick Bill Pardue Doc Jack son being involved CLCB deliberations Speed Advisory Com mittees proposal ban decided make set ourselves just see what fuss n furor about determined satisfaction 9180 mph record reaffirms effective set coupled-lines could made used minimal expenditure time money effort made slipping 40 short 3/16 1/4 lengths tubing onto old used throughout 1974 including NATS set lines taping place about 6 apart using 1/8-in wide Chart-Pack tape used no special hand made parts no glue epoxy sol der st tape holding rear line OD tubes cut tape wings about 1/8-in lengths rest process using no accurate measurements simple eye ball approach entire fabrication process took us fidgety 14-year-old near-sighted old man less three hours resulted increasing Streak ers speed by9 mph raising AMA record better 6 mph continued use same small plastic reel lines originally came experienced no jamming problems whatsoever So please forgive us brief digression describing Streaker design wanted debunk some mythology has published about difficult dangerous coupled-lines manu facture use can made safely economy ease belief used sizes will provide equal competitiveness between Mono-line coupled-lines might just re vitalize long-waning interest ac tivity pure Speed events Just prove Streaker doesnt need coupled-lines go fast set earlier National Record 8292 mph 1971 placed second Profile Proto event 1971 1974 NATS addition has placed top three almost contest entered throughout its long career including Eastern States Championships meets Construction Acceleration key success proto-speed events weight primary design consideration However durability must also achieved faced making trade-offs between two Streaker design incorpo rated single full-fuselage-length lower engine bearer see plans design feature attribute fact original 4-year-old model still competing successfully long thin strip maple permits narrow 3/16 fuselage same time provides solid mount engine tank horizontal tail landing gear also damps-out engine vibration throughout full length fuselage short upper engine bearer 1/32 plywood doublers other hand pro vide forward fuselage stiffness solid wing mount well transmitting engine continued page 42 August1975 39 1/2A Streaker vibration another large surface wing additional damping Thus fairly rigid cohesive assembly formed allowing engine operate peak performance minimum power-robbing vibration virtually no weight penalty Since full-size plans accompany article construction Streaker should easily understood will bore infinite details will touch highlights try explain unique fea tures Virtually hardware used original tank bellcrank engine pressure backplate fine-adjustment needle valve lefthand rotation crankshaft prop purchased Kirn-Kraft P0 Box 224 Anaheim Calif 92805 ole speed specialist Dale Kim has large selection specialized items available should interest anyone wanting pursue small-engine racing events So dont build Streaker would advantage send list available goodies particular recommend lefthand rotation props Proto events supplies detailed instruc tions prop modifications may well add some mphs models use [H prop crankshaft highly recommended order utilize en gines torque effect maintain line tension during critical take-off phase also eliminates need adding weight outboard wing-tip turn keeps overall model weight lower Although Dale can provide LH crankshaft TeeDee may want try local hobby shop first can order direct Cox engine used ob viously Cox TeeDee 049 really isnt other readily available engine compete days Inci dentally again Kirn-Kraft can pro vide fully set-up TeeDee 049 lefthand shaft pressure backplate special fine-threaded needle valve dont want own engine modifications Weve shown general dimensions suitable tank can make shim brass plans However did use pre-fab tank Kirn-Kraft con junction engine backplate having pressure fitting order bleed crankcase pressure fuel tank stable engine run use single ward-facing vent tube tank enables operate either normal suction-type fuel flow just plug remove pressure tap engine backplate pressurized system talking about prop above should have mentioned can also use Tornado 5 diameter 4 pitch nylon prop readily available hobby-shops Although prop won t give quite same high speed performance excellent choice test flying and/or learning fly pylon use regularly benchrunning engines checking out new fuels familiarization flights after long winter inactivity Theyll serve quite well anything except top-level competition flying wheels used Proto models 3/4 diameter Williams Brothers hobby shops stock use tail-wheels larger models Alternates available too course key selection should size weight Especially seek out thinnest possible wheels reduce drag mini mum Weve tried smaller 1/2 diame ter wheels can create problems anything smoothest take-off landing surfaces dependability stick 3/4-in size recommend same landing gear bent shape 1/16-in diameter music wire held place woodscrew washer top plus small clips made aluminum brass shim stock side secured 2-56 bolt through fuselage also hold front tank mount clip tail skid bent shown 1/16-in wire glued place epoxy Epoxy prime adhesive used construction Streaker body parts basic balsa fuselage maple engine bearers/crutch plywood frontend doublers assembled using epoxy cement normally use fastdrying types put Out Hobby-Poxy Dev con other sources Assembly tail surfaces fuselage also done continued page 77 42 Model Aviation Left hand clockwise turning Cox Tee Dee obtained Kim Barry Pallet Streaker model posed front trophy collec Kraft Iefthand prop hardware small engines tion brother Bruce accumulated various events Kim specialty Complete information article Sky-Scrapers T-shirt Pailet clan members FF clubl Streaker continued page 42 epoxy installation elevator hinges horizontal stabilizer elevator carved sanded shape before elevator cut away full tail piece After cutting planform 3/32-in hard sheet balsa should shaped approximate airfoil contour shown shape critical must symmet rical elevator cut away stabilizer hinges installed hinges simply short lengths 1/16-in OD aluminum tubing slipped over length 1/32-in music wire epoxied alternately stab elevator small elevator horn can made aluminum stock bolted place small piece 1/32- 1/16-in plywood glued elevator epoxy can purchase similar shown hobby shop install whatever manner called vertical tail fin cut 1/32-in sheet plywood leading trailing edges sanded slight taper rounded installed epoxy made plywood better withstand rigors occasional flip-over landing bound occur sooner later especially not-perfectly-smooth land ing site clear plastic canopy required AMA rules event epoxied place intersection fin leading edge top fuselage actual shape really critical can made either modifying small bubble-type canopies sold hobbyshops purchased Kirn-Kraft Carving wing Streaker probably difficult task building model can performed easily following steps described Cut planform shape plank 3/16in thick balsa plans locate proper position small maple bellcrank mount glue wing blank epoxy wing blank still flat-sided would advisable drill bellerank mounting hole through maple insert Begin carving wing tapering its thickness maximum 3/16-in root 1/16-in tip taper should lower surface upper surface remains completely flat tip tip gives very slight di hedral appearance next step best performed fine-tipped magicmarker soft pencil can used alternate Draw straight line normal models wings centerline run ning through bellerank center tip tip both top bottom surfaces wing blank lines locate maximum thickness location airfoil reference during carving process Additional lines should drawn along leading trailing edge faces wing blank running mid-point tip thickness point 1/16-in above lower surface root denote actual airfoil leading trailing edges flat blank carved shape Using line-guides just drawn edges surfaces wing blank basic airfoil shape now can carved find razor plane best tool purpose rest job no further reference special contours templates four basic guidelines will result lifting section root gradu ally changing symmetrical tip specific airfoil contour opinion simply critical Final shaping wing done fairly rough sandpaper use #220 grit prior fine sanding finishing Fuselage construction described general earlier comparable normal profile model normal sequence rough-out side-view shape 3/16-in hard balsa plank install maple engine-bearers epoxy glue epoxy 1/32-in plywood doublers After assembly has dried drill necessary mounting holes engine landing gear tank cut airfoil-shaped openings required wing tail instal lations upper lower fuselage edges should rounded sandpaper Prior final assembly wing/tail/ fuselage recommend given coat hot-fuel-proof butyrate dope order partially seal wood grain afford better glue joint Lightly sand parts medium grit about #320 sandpaper assemble using epoxy glue being especially careful get proper alignment relative other wing-tip line guide can also installed time should either made 1/32-in plywood glued wing aluminum shim stock bolted place entire model should given minimum three coats clear butyrate dope favorite hot-fuel proof sealer/undercoat compound sanding between using fine grit about #400 sandpaper Choice color scheme up original model all-purple name like Streaker maybe fleshcolor would have appropriate simplicity ease touching-up nicks will inevitably result competition flying recommend however stick basic color get too elaborate Another good idea give entire model over-coat clear Hobbypoxy should done after last coat dope has dried least day will provide better protec tion hotter speed fuels Installation landing gear de scribed earlier control system will complete models construction Al though small /2A sized bellcrank will suffice preference special available Kirn-Kraft special because incorporates same lineconnecting system used Monoline devices small brass buttons around line end-loops slip eliminates need special lead-out wires connector clips provides safer attachment because larger area around line end-loop rubs bellcrank-to-elevator horn pushrod made / 16-in music wire bent appropriate length give neutral elevator bellcrank neutral posi tion basic engines unmodified except few small refinements such re moving sharp edges inside crankcases opening venturi throat diameter somewhere between 1 36 150 best size given engine set flying conditions can determined test flying regular high-compression heads Cox now provides TDs quite competi tive have access small lathe can experiment modifying further increase compression ratio generally cut about 015 off Cox head experiment flight testing anywhere three gaskets under head until get best results again expect results vary different fuels climates Another area experimentation can yield signifi cant results try different piston/ cylinder combinations initial flight tests recommend use Cox Red Can fuel Tornado prop adjust controls minimum sensitivity keeping lines close gether about handle last Kirn-Kraft plug . offer fine han dIe /2A speed-flying purposes utilizes Mono-line-type attachment buttons handle end match bellerank Learning fly pylon should offer no difficulty encounter problems getting wrist fork pylon after take-off urge use Barrys method used other youngsters well simply beginning take-off flight wrist alread# fork After few famil iarization flights try Kirn-Kraft props some hotter fuel Competition fuels very much func tion weather idiocyncracies particular engine Readily avail able hot fuels such Ramm K&B Speed Fuel certainly worth try home-brews depend heavily upon magic potions concocted Frank Garzon can offer tip ver use less 60 percent nitro mix model weighs five ounces less fly AMA regulations lines 008 diameter 42 long competitive speeds will right around 80 mph Any thing under 75 mph calls continued work engine/prop/fuel combina tions get 80-mph bracket II meet Lake Charles Louisiana 1975 Nationals summer see Streaker can beat Barrys original ole-reliable Streaker August1975 77