The Sportsman

N &porfsman Harold Ruark THE SPORTSMAN could easily scale model beautiful high-wing air plane 30s unforgettable lines could equally beautiful homebuilts today Actually neither Sportsman designed look like full-size airplane enough wing tail make pleasant flying machine have modeler over 40 years can see age controlling style thinking airplane result two previous models flown trike gear began 30 engine 30 engine just wasnt enough Sportsman powered OS 40 man what difference Plenty power Realistic pretty come 40-powered job rewarding project both building flying take-off no worries about snap rolls good 35 would okay consider 40 just right comment two before go con struction Although beginners air plane isnt difficult build fly modeler moderate amount expe rience will have no trouble two items concern may fiberglass cowl wheel pants pants can purchased almost model supply house cowl can easily made method described upright engine installation just straightforward model building still looks good Sullivan spinner So lets get started enjoyable part construc tion flying 6 Model Aviation I Construction Fuselage Begin two pieces 1/8 x 6 x 36 medium balsa enough sides frames Follow arrow heads drawing initial cuts After sides have cut edges trued glue two 1/8 x 1/4 bottom stringers sides Make sure stringers 1/16 below sides bottom edge will see later done Cut out 1/16 ply doubler glue forward section back forward side F-2 Now let stringers plywood doublers dry Using scrap left sides make up frames careful plan two pieces aft top half fuse cabin stabilizer plenty material two sheets Glue together two halves frames 5 minute epoxy make up quick way Now cut 1/32 ply doubler F-2 F-3 glue balsa frames epoxy stage must decide will build model fiberglass cowl use upright engine hardwood mounts firewall-mounted engine used glass cowl make firewall F-l 1/4 plywood balsa nose upright engine contemplated F-I cut 3/16 plywood fiberglass cowl makes very pretty airplane isnt much trouble Ill explain method shortly time components cut out glued should dry ready assembling frames Mark ver tical centerline will help true alignment fuselage Mark frame lines fuse sides laying over drawings spotting proper loca tions markings can easily made fine-point nylon-tip pen Everyone has favorite method sembly have factory-made jig fine heres way Using flat board approximately 38 long 6 wide draw centerline F-2 F-3 four notched pieces sawed soft pinetwo top two bottom Width notches should equal width frame plus 1/4 two sides Make notches snug fit Use 15 mm epoxy glue two frames sides notched pine clamps hold together Make sure centerlines over line building board cer tain firewall ends square across building board simple easy way get true fuselage After two frames have dried add fire wall frames F-4 F-5 jointing tail together scrap piece balsa have kept centerlines frames over centerline build ing board construction will true Using white glue glue choice add rear side panels rear top center curved 1/4 stringer back F-S youve allowed dry overnight notch out add piece /8 ply landing gear glue place medium /s x /2 balsa add re inforcement over landing gear area top wing saddle also put place vertical struts stiffen cabin sides dry add balsa triangle stock up sides F-2 across plywood landing gear mount shown plans next step complete forward F-2 Add /4 x /2 balsa stock bottom edge Carve bottom block shape shown plans out two pieces k stock youre lucky enough have some Hollow lighten following dotted lines plans gives tremendous strength forward sec tion upright engine used carry blocks out nose add k cheek blocks over hardwood rails add nose block Carve entire unit together cutting out nose suit engine used fuel tank location shown works alright either side-mounted upright engine installation Build hatch shown plans hatch nose planking can covered piece 1/16 sheet balsa Wet little top glue white glue forewall mount fiber glass cowl used wood con struction stops F-I everything finished point lay whole works aside forget awhile Tail Surfaces always build tail surfaces next As drawings show everything straightforward construc tion open framework fin should medium grade /4 balsa other balsa tail surfaces should light Build up stab frame /8 X Y8 balsa over plans flat board gluing 1/16 sheet both sides Clamp tween two pieces 3/4 straight pine plywood let dry gives per fectly straight no-warp stabilizer Build movable rudder stab sections August1975 7 Opposite The designer ready fly Sportsmanits easy see people have yen cabin jobs Above partsdisplayed just before coveringshow things augment drawings Mylar hinges elevators fin barndoor aileron set-up etc Sportsman a Insert piece ard wood between two halves ele vator Taper round off edges shown plans Use nylon hinges indicated Wing Select balsa properly different components 1/16 sheet should light-medium grade 3/32 ribs should soft light spars should medium-hard Begin mak ing two plywood patterns wing ribs Cut out ribs rough clamp bolt between two plywood patterns Carve sand shape long flat sanding block wing jig great method building flat-bottom wings use two pieces flat straight boards x 12 x 36 Nail boards cen ter joint workbench Using wing drawing law off wing rib lines outside leading edge line boards Take two strips 7/8 high x 12 long raise ends boards place strips po sition shown drawing Nail strips wing board securely bench produces v/s dihedral Make eight triangu lar wing tip jig blocks shown plans Nail two pine strips approximately 4 along outside LE line wing boards Cover entire board wax paper Next tack glue nail wing tip jig blocks place Using piece 1/16 x 2 x II sheet balsa pin place blocks Cut proper angle balsa LE glue tip sheet pinning nailing firm strip building board Select bot tom 1/16 sheet glue LE tip sheeting pin board Cut glue forward bottom wing spars place us ing several wing ribs place spars proper position Repeat trailing edge bottom sheeting spar Glue wing ribs except two W-2 ribs side center wing Build up spar aile ron section added angled k aileron frame add A-I ribs Make sure 1/16 space provided between end A-I rib W-2 wing rib aileron cutout clearance Epoxy plywood W-4 LE brace wing spare plywood braces W-5 W-7 Cut off 1/16 remaining two W-2 wing ribs glue place Add 1/2 x 3/4 balsa block 1/16 plywood W-4 LE brace block fits tight betwecn two W-2 wing ribs Install /8 W-6 balsa frame between W-2 wing ribs glue wing rib Note center sec tion wing approximately 1/8 thick TE will fair out straight across finished fuselage Add soft pine tapered blocks TE sec tion wing hold-down bolt Install top wing spars fair up sanding block covering 1/16 sheet After wing framing com pleted add top sheeting two 1/16 LE sheets stop W-2 ribs wing LE stops Dihedral top wing stops fuselage sides wing top straight across fair windshield block TE top sheeting edge beveled fit top bottom sheeting TE sheet can continue across center wing half W-l rib TE sheet fitted has glued lay piece wax paper over joint Take two pine strips about wo yardsticks nail through TE 6 nails available hardware store building board Keep about half stick board other half wing edge After wing has dried makes true no-warp edge scrape ends fill section across top wing point wing almost com pleted Let everything dry day night remove jig finish planking bottom center section stall servo box aileron mount ing platform Glue wing tip blocks carve yet Saw out dress ailerons clean up aileron section clearance wing Now time carve wing tips fair ailerons Cap wing ribs 1/16 x 1/4 balsa sand everything smooth long block Install wing dowels Install wing fuse mark position windshield block Carve windshield block almost its proper shape leaving some fair top wing Glue block place 1/16 plywood plate F-2 fuselage catch wing dowels Remove wing stall wing bellcranks other aileron hardware Use three hinges aile ron Pin hinges little peace mind after gluing epoxy Use Carl Goldbergs short mini-horns links own favorite sys tems Hook everything up servo test before covering sure working correctly free Fiberglass Cowl Now wood work nearly completed will get back glass cowl Using side elevation fuselage trace outline nose back 1/4 beyond F-I likewise trace cowl lines top view nose section A-A air plane F-I make template nose shape point Using piece foam may have glue two pieces together draw outlines have made drawings onto side top rear end block Saw out block following outlines sharp knife block can easily carved Finish sanding same size nose block placed up F-I fairs out lines airplane sides should protrude fuselage about 3/8 let out air will enter nose After carving sanding finished epoxy piece scrap wood about 2 x 3 x 3 2 side center back carved block hold block firm vise clamp anything will hold free fiberglass cloth can laid up touching anything except foam block Coat foam heavily continued page 70 8 Model Aviation Almost too pretty fly covered painted Sportsman shows re flections its finishnote bottom wing instance Snug clean cowl hides side-mounted 40 engine detailed right plans leave up builder select install commercial type mount Judging angle braces author really got vibrations out De signer also provides information built-up nose Sportsman continued page 8 three four coats Johnsons Paste Wax filling little holes voids completely Before start lay up cowl get everything ready cutting 6 oz glass cloth approximately 3 strips will lay over block wrinkling Mix resin hot enough will start jell 20-30 minutes will give plenty time lay two coats cloth fill weave full stage forget until has hardened enough handle Sand everything smooth possible foam block time block will have shrunk away cowl should come out easily have holes voids fill epoxytype automotive body putty can purchased auto body repair shop Apply putty-filler small thin rubber squeegee flexible material will put thin coat follow curves Use rough file knock off high places sand smooth wet paper 220 first 400 will give cowl smooth bottle very light Cut out nose air inlet contour shown drawing Holes cylinder head exhaust needle valve will cut after installation engine Dont afraid try cowl its simple build results gratifiing Landing Gear Make main land ing gear strut 3/32 tempered aluminum Using lines drawing bending same profile will pro duce springy little gear Any type commercial wheel pants 55 1/2 range cover 2-1/4 2-1/2 wheel will work out fine wheel pants arent used Bonner 2-1/2 wheels unex posed axles make attractive arrange ment little better grass rough fields tail wheel 1 Wil liams wheel wire leg made scrap end cut off mini-snap-link rod rod bends easily yet has plenty strength tail bushing piece 3/16 dowel close-fit hole wire Bend wire shape leaving top section straight Solder small flat washer position shown draw ing Insert tail wheel wire through dowel bushing Bend leg 90 degrees fit pine block rudder Tail wheel assembly will fitted fuselage after bottom fuselage sheeting has installed Assembly Make sure tail platform level glue stab fuselage Glue fin stab slot onto center top stringer fuselage certain hinge post fin 90 degrees stab use two light cardboard triangles side hold straight until glue dries Next install mounting wing Cut wing holddown plate 1/4 birch plywood Glue place epoxy brace soft pine hard balsa blocks shown After boring forward wing dowel holes wing centered bore nylon screw hole through wing pine insert blocks Mark plywood wingplate bore tap l/4-20 nylon bolt stage carve windshield block shape shown drawings fair top wing Make pattern paper windshield 1/16 3/32 sheet balsa cut glue windshield piece Make sure rabbet thickness windshield balsa out block before trying glue place Remove wing install servo mounting arrangement choice servos approximate loca tion shown plans Use pushrods choice Mine mini-snap-links rod running through piece 1-1/2 long 1/8 dia nylon tubing using balsa pushrods Z-bent 1/16 wire hookup servo arms Hinge rudder ele vator dont glue hinges yet Install horns linkage make sure everything order working Install engine temporarily mount hook up throttle linkage servo controls moving freely re move radio pushrods Now time fair up bottom edges fuselage Install landing gear strut two 6-32 bolts nuts Install bottom frame B-I accord ing plans glue 1/4 x 1/4 stringer through bottom frames Cut glue bot tom 1/16 balsa sheeting grain running lengthwise notch tail wheel assembly cut unit glued place epoxy careful glue wire wood airplane now ready finishing Covering Finishing First sand entire woodwork 120 paper cut down sharp rough edges ready-mix spackling compound avail able paint hardware store fill holes voids smooth over steams spackling dries quickly sands easily satisfied thing filled sand entire woodwork 400 paper Covering materials methods modeler has favorite system starts fuselage Apply two coats dope light sanding txveen coats Using medium-weight Silkspan cover open top section fin first Cut piece medium-weight Silkspan approximately larger half covered Wet Silkspan warm water squeeze out water stretch over open structure Using dope stick Silk span apply forward edge fin start stretching gluing outside edges dont want stick fin cross-framing takes little time easily done Repeat procedure other side Anyone has covered stick-and-tissue model knows technique have tried MonoKote fuselage expect could shrunk properly follow contour dry top fuselage fin blend piece Cover solid woodwork fuselage same way Doping next step Use Aerosol can spray open-frame covered section light coats stick Silkspan framing fin stuck out side edges frame last crossframe top About four five coats will stiffen area enough rest covering should brushed two coats dope stick Silkspan wood try fill paper solid dope Lay airplane aside couple days oils dry out dope Cover wing dope dry ing use MonoKote entire wing havent found anything better Using spackling compound again smooth off fuselage seams overlaps Let dry sand everything 400 paper leaves everything little fuzzy Spray four five coats lacquer automotive-type gray primer until sur face smooth sanding lightly between last two coats Make sure structure dust-free Use epoxy paint spray brush two base coats always use white base coat dry tape off windows windshield trim windows can painted use chrome-trim MonoKote Outline win dows 1/16 black trim tape 6 feet away hard tell difference real glass As modeler knows few extra hours spent finishing time well-spent take pride work results will gratifying everything has dried trim decals added assemble entire ship Install 10 oz Sullivan tank engine radio gear Balance just little nose heavy CG shown drawing balance shouldnt problem Mine balanced out battery positioned shown Flying best part whole project surfaces straight radio checked out engine running properly ease gas up comes tail 05 40 ground roll short will rotate itself Ease little up elevator youre off winging some altitude gained throttle back half-throttle fly forever 10 oz tank know will soon realize best Sunday-flying airplanes youve ever expert con trols isnt bad aerobatics Enjoy Sportsman Its fine airplane 70 Model Aviation PEANUT SCALE I] IPLANS Complete colalog 25c I_________LA 0 BOX 2498 AM MESA CALIF 9204