SFC (Structureless Foam Composites)

MOST OF THE WORLDS BALSA supply being used super-tanker construction told Balsa still available additional demand has forced price up point us feel can no longer afford writer instance appalled balsa price situation 1978 discovered thatitwouldcost$22OOjusttobalsa-sheet anS foot glider wing Foam plastic has coming ever-greater use model construction during past few years current techniques still quite costly because involve use expensive surfac ing materialsbalsa thin plywood special film Such approaches addition being costly too heavy several modeling appli cations especially Free Flight What needed inexpensive way rigidiz ing foam plastic cores add needed strength adding much weight cost building time offer results three years research upon pages What pre sented essentially follow-up fine series articles Evans Lester appearing January-March 1978 issues MA Early research foam plastic experi menting common variety white expanded polystyrene Styrofoam sold lumberyards insulation comes various thick nesses 1 up either 2-or 4-ft wide 8 ft long material has density pound per cubic foot quite cheap problem material poly styrene foam easily dissolved glue dope paint found others have best compatible liquid materials white glue epoxy attempting first seal foam white glue top-coat dope result dope usually man aged find make break seal ruining job eating up foam Early attempts assumed structural rigidity required use supporting wooden structure Leading trailing edges spars some ribs therefore added foam core Besides being time-consuming adding weight expense such reinforcing structures found material future plank cast $270 will build several models new tech nique lightweight construction types modelsFF CL RCwhich promises easier cheaper just strong balsa Ron St Jean designed world-famous Ramrod FF Fifties has put years painstaking re search methods mater ials results interest builders U Ron St Jean totally unnecessary Adequate rigidity almost cases can achieved skin alone full-scale builders designers led Burt Rutan Vari-eze fame reinforcing foam successive layers glass cloth epoxy felt might cheaper easier less toxic cleaner method achiev ing similar result research utilized white glue aliphatic resin silkspan modeling paper structureless foam composites SFC proper techniques approach has proven completely competitive balsa wood terms almost Free-Flight contest work far superior balsa con struction respects such cost Although universally applicable phases model ing foam/silkspan/white-glue approach believed equally feasible FF CL RC models opinion may eventually replace much balsa now being used modeling Balsa/foam comparisons current prices cost making model airplane structure balsa several times using SFC tech nique described below Just strength balsa model may varied selecting wood different sizes densities same may done foam models changing number laminations silkapan use small hardwood plywood pieces and/or epoxy-coating points par ticularly high stress Just case balsa increasing strength foam results weight increases strength weight normal levels balsa foam comparable Constructing ones first foam model could take almost much time building balsa because one-time need make patterns slowness always accom panies learning patterns already avail able several SFC ships have made building time can drop about one-third balsa/tissue model breaks occur foam model merely needs epoxy pieces together results greater strength before break could break wing half instance flying again less half hour Repairing balsa models usually much time-consum ing requires steps process Further less likely get holes solid foam surface built-up balsa wing typical balsa models covering sags tween ribs sometimes spars too creat ing irregularities airflowwhich may reduce performance contours foam 50 Model Aviation rroving tne truction concept Salt Lake City Annual author son took home three first-place trophies two models shown built foam White glue doesnt protect voam trom dope two heavy coats glue didnt keep dope attacking foam panel model close designed factor certainly must contribute sensational performance Burt Rutans full-scale de signs would give foam FF model edge over comparable balsa ships fullscale sailplane field also foam replacing older construction methods because results Making patterns first used -in plywood lumberyard patterns Later made thin cardboard mat board sold art stores ideal purpose Wing stab templates should two piecesone bottom camber top thus split becomes possible include lead-in lead-out pattern portion pattern can accommodate hot wire both before after cutting foam pattern looks like finished airfoil necessary engage foam same time end work also nec essary hot wire depart same time end suppose lead-ins lead-outs provided continue camber angles wing LE TE have tolerance within side cutter can slightly lead lag other Result person can entire job long cutter short enough him control both ends same time bottom camber cut first stop blocks may added upper camber patterns order control wing thickness blocks April 1982 51 lower stab has wooden structure reinforcement w oz upper reinforced its glue/silkspan skin weighs four oz Lighter structure lust strong SFC has tried different types model airplanes foam-composite RC Sailplane gets running flight test improved performance Left author puts Scotsman 850 SFC model cold gray skies Right Leonard St Jean 020-powered Payload model beginning HOG attempt Model placed Nats register finished bottom camber Cutting bows wires power sources Evans/Lester bow described February 1978 issue MA very practical main advantages type automatic tension adjustment wire lengthened heating 52 Model Aviation contrast first bows rigid cutting wire expanded heat tension disappeared Sometimes attempting com pensate tightening wire within bow would either broken stretched utilizing variac variable transformer found nichrome wire necessary since lower voltage could used adjust lower resistance piano wire variac power supply feasible altema tives since easily adjusted differing lengths diameters wire needs to start zero voltage input foam cutter engage piece scrap foam wire turn up variac until wire first starts moving through foam Model train transformers have tried power sources dont have fine enough adjustment Check surplus electronics store variac 100 watts eonaro poses n uniimieo nuvue Juueehpoq Prop blades Unlimited Rubber ship cut block foam inserted special helical box Hub end right Simple Lennie St Jean launches fathersT-tailed A-This 1/2A beginners CL model designed 2 Nordic Glider entirely SFC-builtFrank Hamilton took pictures gaggle Hand-launched Gliders uses SFC wings rudders stabs hardwood fuselages Balsa tissue usually loses arguments witn sagebrush bushes SFC resists punctures set patterns SFC model can cut thin ply artists mat board mat board slightly less durable easier work Patterns shown Payload ship advantage small cutting wire its use results better surface finish have cut foam -in sheets having very smooth finish using solid 008 wire old CL reel Generally solid 012-015 diameter wire good average need nichrome variac used control voltage input lower heat put cutting wire better finish foam will Solid hollow construction FF models having fuselages small cross-section feasible approach appears to go solid way desirable have hollow fuselage can accomplished three ways fuselage may cut covered hollowed out desired gouging anything Moto Tool screwdriver dissolving unwanted foam solvent such gasoline two-piece fuselage right-and-left top-and-bottom halves could have its innards wire-cut away foam could cut sheets -in thick covered both sides assembled just model being made sheet balsa Sanding foam Some believe one-pound foam cannot sanded experience indicates new techniques special care needed weak spots located experience may beefed up additional thicknesses silkspan and/or epoxy coating epoxy especially useful securing wire hooks setting place uses epoxy would used balsa order provide larger pressure-distributing transitional area Without such hooks could torn loose high pressures must withstand have derived following rules thumb determine number thickness silkspan put FF Gas model use standard-weight silkspan GM anything much larger use heavier SGM material Small fuselages double-covered third layer around firewalls front stabil izer rubberbands go around Tails single-covered Small wings single-covered double covering center sections larger models constant-chord wings second covering may run half wayfrom center tip third layer goes about fourth distance edges reinforced overlapping layers instance wing leading edges LE have minimum two layers top covering bottom Should additional LE reinforce ment deemed necessary narrow strips silkspan may added over basic covering sand successfully techniques use sand balsa applied foam quickly ruin material new methods involves switching finer grits sandpaper plastic backing rough sanding * 150 paper about right using *280 finer finishing Grits coarser * 150 should used hogging out large chunks foam cannot wire cut Four precautions observed sanding foam 1 Apply much less pressure sanding wood 2 Immediately stop feel something rolling between sandpaper foam will small sphere loose foam will gouge scratch 3 Avoid bring ing folded edge sandpaper contact foam too will scratch gouge 4 Remove hard spots continue sanding Pick foam smooth begin troublesome hard spots will minimized Reinforcing foam Although silkspan covered foam adequate almost entire airplane few spots will require wood reinforce ment Generally same spots would use plywood balsa model firewalls landing-gear mounts timer mounts some mating surfaces parts rubberbanded together etc April 1982 53 fixture used cut foam needed sheet thickness Vertical board L adiustable blank-cutting bow can handle lengths up 36 cutting wire slides against patterns attached ends blank lttakestwo patternsto cut wing onetorthetop camberand forthe bottom Blocks register bottom camber control thickness Once blank cut bottom camber next Note leadins leadouts guide hot wire top camber almost finished Hot wire has already come through end jig used cutting dihedral angles front face adjustable Undercambered airfoils no problem panel almost compl~ accommodate angle Wet-covering foam silkapan easyjust dont dent foam pressing too hard Large models requiring greater strength require layers paper five six fuselage center constantchord wing two tail Covering fosm basic covering technique about same wet-covering solid surface silkspan trimmed paper dampened enough make fishy expand thinned white glue brushed through silkspan foam glue rubbed well work fingers symmetrically Continued page 118 54 Model Aviation early cutting bOwS ala adjust expansion wire heated allowing wire sag New ones maintain tension wire warms up ntld scrap duu garut uunny wIru wniu adjusting variac determine correct voltage Leading trailing edges reinforced overlapping edges top bottom sheets silkspan silkspan can added needed Half stab covered half Foam seems flimsy until after covered white glue silkapan strengthens tremendously minimal weight gain MASTER AIRSCRIW FLIGHTBOX KIT Master Airscrew Flight Box has features larger boxes compact handy arrangement parts cut imported mahogany plywood will take stain varnish paint finishes overall size 19Wx9%x 12 high $E 495 dealer Qor postpaid California add 6% Sales Tax FEATURES INCLUDE Space battery & meter panel Transmitter compartment Room gallon fuel Propeller storage Gravity closed small parts storage 7/8 aluminum handle Complete instructions & fasteners WINDSOR PROPELLER CO 384 Tesconi Ct Santa Rosa CA 95401 P/i llT5MFC SOOd 50C otIog RC Kits Mfgx I2 16 499-5323 IEAmL706 Easton NEX tKULcanton OH 44721 x seat eventually scale-like pilot achieve near perfect balance overall weight just over 4 lbs 7 oz Although reprints Crickets newsletter supplied included several tips improve service life correct minor problem areas clarify construction steps chose restrict head teeter avoid potential tail boom strikes main rotor other tips should tried necessity dictatesthe old aint broke dont fix philosophy applies significant problem Cricket owners having young children may encountered seat option addedhow keep pilot seat child says Can play doll Dad First flights large bolt taped seat nice finally get fly Cricket using own stick mode found very little difficulty getting things setup fact static set-up instruc tions yielded near perfect flight trims machine adjustment made after first lift-off blade tracking after tracking however experienced vibration during hovering flights believe due possible error adjustment tester spring coning angle vibration excessive however have made no attempt remedy date have received several letters regarding vibra tion problems number different types Helicopters perhaps subject timely Ill share subject comment further Cricket next month Dave Chesney Rt 9 Box 62 IA Greensboro NC 27409 RC Pylon Racing/Hager Continued page 49 would still spend three weeks finishing planes would lot other fliers should make tough new guys area couple years ago decided away scale judging just draw straws takeoff position first didnt like idea after couple years racing Ive changed mind After what interested doing want race put good finish airplane comments would appreciated Bill Hager 706 Glen Haven Dr Conroe TX 77302 SFC/St Jean Continued page 54 center tips bottom flat undercambered wings should covered first order better preserve airfoil design White glue thinned about 60% glue/40% water food coloring dye added dye colors work identifies glue voids spots no color Aliphatic resin thinned 50/50 refer mix Nudope Since covering shrinks upon drying wise either cover opposite side shortly after first almost dry redampen flatten just before doing second side order minimize warpage final product Should need remove warp add adjustment can easily accomplished heat An electric heater works finejust careful nbt melt foam structures however have memory tends show up very hot days better cut adjustments foam start feasible covered model sanded #150 regular paper before finishing adding addi 118 Model Aviation WARNING Tests have shown GloBee Glow Plugs habit forming Write TWinn-K Inc Dept GB3 Indianapolis Indiana 46231 FP THF RFRT IN RADIO CONTROL Id iUPoL U1IMUNN F7FTIGERCATSUPER HUNTER 6OSIZE ACRO TRAINER 40 SIZE DUCTED FAN F-lOG DELTA DART 0 FORMULA 1 HIGH PERFORMANCE PROPELLERS DIV AIRSCREW EACH PROPELLER HAND BALANCED Herd Eastern Maple Accurate airfoil pitch 44 C 858X65Rj 8s8X74i9 Additional propellers evailebla loxeJO CUSTOM DESIGN UPON REQUEST DISECT SALAS ONLY W PRODUCTS' IX postog handling SAXA CRYSTAL COUNT$150 FOR COD ond SANTA ROSA 54O4 CA PEA ADO N% TAX PSONE IYOl 528ROSA tional thicknesses paper Final hunildity-proof finish film used finish SFC model inexpensive can purchased grocery store quite light about -mu thickness easily quickly applied almost infinitely heat-shrinkable Saran Wrapnot original product fairly new called Freezing Microwave Saran Wrap few tips putting Put light coat spray adhesive structure covering large area feasible order minimize overlaps later masking eliminate glue spray finished work cause films heat-shrinking ability can entire top polyhedral wing Make sure adhesive fully set-up before adding Saran 3Ms *77 spray adhesive adequate Make certain solvent adhesive has evaporated before pressing plastic place Once film place rub work edges joints secure heatshrinking best done ordinary 250-watt heat lamp Just paint heat onto Saran being sure keep lamp moving no closer needed shrink film four five inches get too close tarry too long spot foam can melt little heat shrinking good idea hold film adjacent edge pulling away work will prevent its shrinking away edge work After area shrunk should immediately burnished foam surface Kleenex still hot permanent attachment Any entrapped air can gradually worked out Finally Saran trimmed new razor blade edges finished MonoKote iron low Continued page 126 taimt0 wset&e tiA CoS lbL4ed dO 14tIUThTL LflC April 1982 119 MIDWEST PRODUCTS COMPANY INC 400 S Indiana St Hobart Indiana 46342 219 942-1134 Send $100 catalog Look Future Product DeveIopmen Full Command Systems Manufacturers EK Logitrol radios accessories py eai Dealer Inquiries Welcome Full Command Systems 9O8ERo sewood Spokane WA 99207 . 509 487-2122 414 90 1 r CaQtcg213 76 JIceceggoktcgPO BOX R/C GOODIES 192 S VAN NUYS CA 91408I month 3uvdia offering SPECIAL PRICES several accessory items RegularI 1prices shown small tvoe BARGAIN PRICES shown heavy typeI VCAPS$895UNIVERSAL SERVO TRAY Hi Visibility 2Color Caps I match 72 MHz Freq Specify size fits 5289 AIR-FLO HINGES21 tray Bantam Connon N OCE3 CE4 CE5 Futaba Kraft KPS12 Midget servos1 mcMtg hardware included C Q FREQUENCY FLAGS j 051 Golden Bee etc Uses Iron Hinges easy chable holder1 standard 1/432 glow pluginstall Strips 36 Ig polyester ribbons $209SMALL 1iLARGE 1 1/2All Frec colors $169$149 $169I Urn$2500$169$199 VISA ORParts Ship 7 Calif add Soles Tax Catalog 604 MORE US $1 70 Foreign Add 4-1/2% Visor Master Cordj heat desired Saran film may painted inside prior application Most spray paint will work will look like expensive factory-painted -glued Mylar films small fraction cost Scotch Monocoat will exclude moisture better before painting Since F&M Saran Wrap softer Mylar does tend get scuffed up bit making landings hard sufface such spots turn up easily repaired bit 5-mm epoxy smeared bad spot might instead put piece Mylar over spot Conclusions seems ridiculous believe piece flimsy highly-flexible easilysquashed piece foam could stiffened given enough strength addition mere paper glue become competitive model airplane begins cover long thin wing instance first thought handling delicate coat might might well try cover wet noodle once foam has taken its paper clothing undergoes transforma tion unlike metamorphosis David Banner turning Hulk say proof pudding eating What will such model competi tion date foam fleet has won nine trophies five contests using first-generation hardware SFC approach has now used success fully several types FF models including Hand-Launched Gliders P-30 Coupe Un limited Rubber models A-i Towline Gliders catapult gliders well classes AMA Gas 020s through Class D SFC natural CL Combat wings perhaps 45 models built far three RC tremendous potential also especially Quarter Scale beginners FF gas model using reed-valve 049 has built successfully tested almost lost third flight will subject follow-up article soon appear pages have recently discovered inherentlymore-efficient tapered wings can SFC-built slight increase time effort addition several layers silkspan usually required beef-up center thicker wider airfoil doing job instead results lighter overall model efficient well After years research development testing evaluation SFC concepts techniques convinced ever could eventually replace balsa wood long modelers approach open mind relative prices balsa foam reverse detailed SFC data special materials available directly author 3744 E Nye Lane Carson City NV 89701 Please send SASE inquiring FF Duration/Meuser Continued page 57 wing found formerly severe flutter problem virtually disappeared add ing diagonal ribs both increased torsional stiffness wing moved its CG forward difficult say effect turned trick Deluxe flufi~ dispenser use cattail fluffies thermal-detecting aid has become quite standard have habit making mess cute trick get upwind 126 Model Aviation Division B & B Industries Looking Hard Find Soaring Goodies Jfe &i4fane fT/acory o has complete comprehensive line R/G Soaring productstoeverexist North America o Our line products includesthosefrom some respected firms Europe well complete inventory own US manufacturers o We carry complete line Kits Hardware Accessories & Building Supplies have full inventory Launching Equipment & Related Products o We serve serious R/G soaring enthusiast supplies kits other items have sought long Call write today Free product listing & price sheet Sailplane Fcto717 244 4508 PO Box 34 Red Lion PA 173569am- 9pm EST PS Come see displays 1982 WRAMS & TOLEDO shows

MOST OF THE WORLDS BALSA supply being used super-tanker construction told Balsa still available additional demand has forced price up point us feel can no longer afford writer instance appalled balsa price situation 1978 discovered thatitwouldcost$22OOjusttobalsa-sheet anS foot glider wing Foam plastic has coming ever-greater use model construction during past few years current techniques still quite costly because involve use expensive surfac ing materialsbalsa thin plywood special film Such approaches addition being costly too heavy several modeling appli cations especially Free Flight What needed inexpensive way rigidiz ing foam plastic cores add needed strength adding much weight cost building time offer results three years research upon pages What pre sented essentially follow-up fine series articles Evans Lester appearing January-March 1978 issues MA Early research foam plastic experi menting common variety white expanded polystyrene Styrofoam sold lumberyards insulation comes various thick nesses 1 up either 2-or 4-ft wide 8 ft long material has density pound per cubic foot quite cheap problem material poly styrene foam easily dissolved glue dope paint found others have best compatible liquid materials white glue epoxy attempting first seal foam white glue top-coat dope result dope usually man aged find make break seal ruining job eating up foam Early attempts assumed structural rigidity required use supporting wooden structure Leading trailing edges spars some ribs therefore added foam core Besides being time-consuming adding weight expense such reinforcing structures found material future plank cast $270 will build several models new tech nique lightweight construction types modelsFF CL RCwhich promises easier cheaper just strong balsa Ron St Jean designed world-famous Ramrod FF Fifties has put years painstaking re search methods mater ials results interest builders U Ron St Jean totally unnecessary Adequate rigidity almost cases can achieved skin alone full-scale builders designers led Burt Rutan Vari-eze fame reinforcing foam successive layers glass cloth epoxy felt might cheaper easier less toxic cleaner method achiev ing similar result research utilized white glue aliphatic resin silkspan modeling paper structureless foam composites SFC proper techniques approach has proven completely competitive balsa wood terms almost Free-Flight contest work far superior balsa con struction respects such cost Although universally applicable phases model ing foam/silkspan/white-glue approach believed equally feasible FF CL RC models opinion may eventually replace much balsa now being used modeling Balsa/foam comparisons current prices cost making model airplane structure balsa several times using SFC tech nique described below Just strength balsa model may varied selecting wood different sizes densities same may done foam models changing number laminations silkapan use small hardwood plywood pieces and/or epoxy-coating points par ticularly high stress Just case balsa increasing strength foam results weight increases strength weight normal levels balsa foam comparable Constructing ones first foam model could take almost much time building balsa because one-time need make patterns slowness always accom panies learning patterns already avail able several SFC ships have made building time can drop about one-third balsa/tissue model breaks occur foam model merely needs epoxy pieces together results greater strength before break could break wing half instance flying again less half hour Repairing balsa models usually much time-consum ing requires steps process Further less likely get holes solid foam surface built-up balsa wing typical balsa models covering sags tween ribs sometimes spars too creat ing irregularities airflowwhich may reduce performance contours foam 50 Model Aviation rroving tne truction concept Salt Lake City Annual author son took home three first-place trophies two models shown built foam White glue doesnt protect voam trom dope two heavy coats glue didnt keep dope attacking foam panel model close designed factor certainly must contribute sensational performance Burt Rutans full-scale de signs would give foam FF model edge over comparable balsa ships fullscale sailplane field also foam replacing older construction methods because results Making patterns first used -in plywood lumberyard patterns Later made thin cardboard mat board sold art stores ideal purpose Wing stab templates should two piecesone bottom camber top thus split becomes possible include lead-in lead-out pattern portion pattern can accommodate hot wire both before after cutting foam pattern looks like finished airfoil necessary engage foam same time end work also nec essary hot wire depart same time end suppose lead-ins lead-outs provided continue camber angles wing LE TE have tolerance within side cutter can slightly lead lag other Result person can entire job long cutter short enough him control both ends same time bottom camber cut first stop blocks may added upper camber patterns order control wing thickness blocks April 1982 51 lower stab has wooden structure reinforcement w oz upper reinforced its glue/silkspan skin weighs four oz Lighter structure lust strong SFC has tried different types model airplanes foam-composite RC Sailplane gets running flight test improved performance Left author puts Scotsman 850 SFC model cold gray skies Right Leonard St Jean 020-powered Payload model beginning HOG attempt Model placed Nats register finished bottom camber Cutting bows wires power sources Evans/Lester bow described February 1978 issue MA very practical main advantages type automatic tension adjustment wire lengthened heating 52 Model Aviation contrast first bows rigid cutting wire expanded heat tension disappeared Sometimes attempting com pensate tightening wire within bow would either broken stretched utilizing variac variable transformer found nichrome wire necessary since lower voltage could used adjust lower resistance piano wire variac power supply feasible altema tives since easily adjusted differing lengths diameters wire needs to start zero voltage input foam cutter engage piece scrap foam wire turn up variac until wire first starts moving through foam Model train transformers have tried power sources dont have fine enough adjustment Check surplus electronics store variac 100 watts eonaro poses n uniimieo nuvue Juueehpoq Prop blades Unlimited Rubber ship cut block foam inserted special helical box Hub end right Simple Lennie St Jean launches fathersT-tailed A-This 1/2A beginners CL model designed 2 Nordic Glider entirely SFC-builtFrank Hamilton took pictures gaggle Hand-launched Gliders uses SFC wings rudders stabs hardwood fuselages Balsa tissue usually loses arguments witn sagebrush bushes SFC resists punctures set patterns SFC model can cut thin ply artists mat board mat board slightly less durable easier work Patterns shown Payload ship advantage small cutting wire its use results better surface finish have cut foam -in sheets having very smooth finish using solid 008 wire old CL reel Generally solid 012-015 diameter wire good average need nichrome variac used control voltage input lower heat put cutting wire better finish foam will Solid hollow construction FF models having fuselages small cross-section feasible approach appears to go solid way desirable have hollow fuselage can accomplished three ways fuselage may cut covered hollowed out desired gouging anything Moto Tool screwdriver dissolving unwanted foam solvent such gasoline two-piece fuselage right-and-left top-and-bottom halves could have its innards wire-cut away foam could cut sheets -in thick covered both sides assembled just model being made sheet balsa Sanding foam Some believe one-pound foam cannot sanded experience indicates new techniques special care needed weak spots located experience may beefed up additional thicknesses silkspan and/or epoxy coating epoxy especially useful securing wire hooks setting place uses epoxy would used balsa order provide larger pressure-distributing transitional area Without such hooks could torn loose high pressures must withstand have derived following rules thumb determine number thickness silkspan put FF Gas model use standard-weight silkspan GM anything much larger use heavier SGM material Small fuselages double-covered third layer around firewalls front stabil izer rubberbands go around Tails single-covered Small wings single-covered double covering center sections larger models constant-chord wings second covering may run half wayfrom center tip third layer goes about fourth distance edges reinforced overlapping layers instance wing leading edges LE have minimum two layers top covering bottom Should additional LE reinforce ment deemed necessary narrow strips silkspan may added over basic covering sand successfully techniques use sand balsa applied foam quickly ruin material new methods involves switching finer grits sandpaper plastic backing rough sanding * 150 paper about right using *280 finer finishing Grits coarser * 150 should used hogging out large chunks foam cannot wire cut Four precautions observed sanding foam 1 Apply much less pressure sanding wood 2 Immediately stop feel something rolling between sandpaper foam will small sphere loose foam will gouge scratch 3 Avoid bring ing folded edge sandpaper contact foam too will scratch gouge 4 Remove hard spots continue sanding Pick foam smooth begin troublesome hard spots will minimized Reinforcing foam Although silkspan covered foam adequate almost entire airplane few spots will require wood reinforce ment Generally same spots would use plywood balsa model firewalls landing-gear mounts timer mounts some mating surfaces parts rubberbanded together etc April 1982 53 fixture used cut foam needed sheet thickness Vertical board L adiustable blank-cutting bow can handle lengths up 36 cutting wire slides against patterns attached ends blank lttakestwo patternsto cut wing onetorthetop camberand forthe bottom Blocks register bottom camber control thickness Once blank cut bottom camber next Note leadins leadouts guide hot wire top camber almost finished Hot wire has already come through end jig used cutting dihedral angles front face adjustable Undercambered airfoils no problem panel almost compl~ accommodate angle Wet-covering foam silkapan easyjust dont dent foam pressing too hard Large models requiring greater strength require layers paper five six fuselage center constantchord wing two tail Covering fosm basic covering technique about same wet-covering solid surface silkspan trimmed paper dampened enough make fishy expand thinned white glue brushed through silkspan foam glue rubbed well work fingers symmetrically Continued page 118 54 Model Aviation early cutting bOwS ala adjust expansion wire heated allowing wire sag New ones maintain tension wire warms up ntld scrap duu garut uunny wIru wniu adjusting variac determine correct voltage Leading trailing edges reinforced overlapping edges top bottom sheets silkspan silkspan can added needed Half stab covered half Foam seems flimsy until after covered white glue silkapan strengthens tremendously minimal weight gain MASTER AIRSCRIW FLIGHTBOX KIT Master Airscrew Flight Box has features larger boxes compact handy arrangement parts cut imported mahogany plywood will take stain varnish paint finishes overall size 19Wx9%x 12 high $E 495 dealer Qor postpaid California add 6% Sales Tax FEATURES INCLUDE Space battery & meter panel Transmitter compartment Room gallon fuel Propeller storage Gravity closed small parts storage 7/8 aluminum handle Complete instructions & fasteners WINDSOR PROPELLER CO 384 Tesconi Ct Santa Rosa CA 95401 P/i llT5MFC SOOd 50C otIog RC Kits Mfgx I2 16 499-5323 IEAmL706 Easton NEX tKULcanton OH 44721 x seat eventually scale-like pilot achieve near perfect balance overall weight just over 4 lbs 7 oz Although reprints Crickets newsletter supplied included several tips improve service life correct minor problem areas clarify construction steps chose restrict head teeter avoid potential tail boom strikes main rotor other tips should tried necessity dictatesthe old aint broke dont fix philosophy applies significant problem Cricket owners having young children may encountered seat option addedhow keep pilot seat child says Can play doll Dad First flights large bolt taped seat nice finally get fly Cricket using own stick mode found very little difficulty getting things setup fact static set-up instruc tions yielded near perfect flight trims machine adjustment made after first lift-off blade tracking after tracking however experienced vibration during hovering flights believe due possible error adjustment tester spring coning angle vibration excessive however have made no attempt remedy date have received several letters regarding vibra tion problems number different types Helicopters perhaps subject timely Ill share subject comment further Cricket next month Dave Chesney Rt 9 Box 62 IA Greensboro NC 27409 RC Pylon Racing/Hager Continued page 49 would still spend three weeks finishing planes would lot other fliers should make tough new guys area couple years ago decided away scale judging just draw straws takeoff position first didnt like idea after couple years racing Ive changed mind After what interested doing want race put good finish airplane comments would appreciated Bill Hager 706 Glen Haven Dr Conroe TX 77302 SFC/St Jean Continued page 54 center tips bottom flat undercambered wings should covered first order better preserve airfoil design White glue thinned about 60% glue/40% water food coloring dye added dye colors work identifies glue voids spots no color Aliphatic resin thinned 50/50 refer mix Nudope Since covering shrinks upon drying wise either cover opposite side shortly after first almost dry redampen flatten just before doing second side order minimize warpage final product Should need remove warp add adjustment can easily accomplished heat An electric heater works finejust careful nbt melt foam structures however have memory tends show up very hot days better cut adjustments foam start feasible covered model sanded #150 regular paper before finishing adding addi 118 Model Aviation WARNING Tests have shown GloBee Glow Plugs habit forming Write TWinn-K Inc Dept GB3 Indianapolis Indiana 46231 FP THF RFRT IN RADIO CONTROL Id iUPoL U1IMUNN F7FTIGERCATSUPER HUNTER 6OSIZE ACRO TRAINER 40 SIZE DUCTED FAN F-lOG DELTA DART 0 FORMULA 1 HIGH PERFORMANCE PROPELLERS DIV AIRSCREW EACH PROPELLER HAND BALANCED Herd Eastern Maple Accurate airfoil pitch 44 C 858X65Rj 8s8X74i9 Additional propellers evailebla loxeJO CUSTOM DESIGN UPON REQUEST DISECT SALAS ONLY W PRODUCTS' IX postog handling SAXA CRYSTAL COUNT$150 FOR COD ond SANTA ROSA 54O4 CA PEA ADO N% TAX PSONE IYOl 528ROSA tional thicknesses paper Final hunildity-proof finish film used finish SFC model inexpensive can purchased grocery store quite light about -mu thickness easily quickly applied almost infinitely heat-shrinkable Saran Wrapnot original product fairly new called Freezing Microwave Saran Wrap few tips putting Put light coat spray adhesive structure covering large area feasible order minimize overlaps later masking eliminate glue spray finished work cause films heat-shrinking ability can entire top polyhedral wing Make sure adhesive fully set-up before adding Saran 3Ms *77 spray adhesive adequate Make certain solvent adhesive has evaporated before pressing plastic place Once film place rub work edges joints secure heatshrinking best done ordinary 250-watt heat lamp Just paint heat onto Saran being sure keep lamp moving no closer needed shrink film four five inches get too close tarry too long spot foam can melt little heat shrinking good idea hold film adjacent edge pulling away work will prevent its shrinking away edge work After area shrunk should immediately burnished foam surface Kleenex still hot permanent attachment Any entrapped air can gradually worked out Finally Saran trimmed new razor blade edges finished MonoKote iron low Continued page 126 taimt0 wset&e tiA CoS lbL4ed dO 14tIUThTL LflC April 1982 119 MIDWEST PRODUCTS COMPANY INC 400 S Indiana St Hobart Indiana 46342 219 942-1134 Send $100 catalog Look Future Product DeveIopmen Full Command Systems Manufacturers EK Logitrol radios accessories py eai Dealer Inquiries Welcome Full Command Systems 9O8ERo sewood Spokane WA 99207 . 509 487-2122 414 90 1 r CaQtcg213 76 JIceceggoktcgPO BOX R/C GOODIES 192 S VAN NUYS CA 91408I month 3uvdia offering SPECIAL PRICES several accessory items RegularI 1prices shown small tvoe BARGAIN PRICES shown heavy typeI VCAPS$895UNIVERSAL SERVO TRAY Hi Visibility 2Color Caps I match 72 MHz Freq Specify size fits 5289 AIR-FLO HINGES21 tray Bantam Connon N OCE3 CE4 CE5 Futaba Kraft KPS12 Midget servos1 mcMtg hardware included C Q FREQUENCY FLAGS j 051 Golden Bee etc Uses Iron Hinges easy chable holder1 standard 1/432 glow pluginstall Strips 36 Ig polyester ribbons $209SMALL 1iLARGE 1 1/2All Frec colors $169$149 $169I Urn$2500$169$199 VISA ORParts Ship 7 Calif add Soles Tax Catalog 604 MORE US $1 70 Foreign Add 4-1/2% Visor Master Cordj heat desired Saran film may painted inside prior application Most spray paint will work will look like expensive factory-painted -glued Mylar films small fraction cost Scotch Monocoat will exclude moisture better before painting Since F&M Saran Wrap softer Mylar does tend get scuffed up bit making landings hard sufface such spots turn up easily repaired bit 5-mm epoxy smeared bad spot might instead put piece Mylar over spot Conclusions seems ridiculous believe piece flimsy highly-flexible easilysquashed piece foam could stiffened given enough strength addition mere paper glue become competitive model airplane begins cover long thin wing instance first thought handling delicate coat might might well try cover wet noodle once foam has taken its paper clothing undergoes transforma tion unlike metamorphosis David Banner turning Hulk say proof pudding eating What will such model competi tion date foam fleet has won nine trophies five contests using first-generation hardware SFC approach has now used success fully several types FF models including Hand-Launched Gliders P-30 Coupe Un limited Rubber models A-i Towline Gliders catapult gliders well classes AMA Gas 020s through Class D SFC natural CL Combat wings perhaps 45 models built far three RC tremendous potential also especially Quarter Scale beginners FF gas model using reed-valve 049 has built successfully tested almost lost third flight will subject follow-up article soon appear pages have recently discovered inherentlymore-efficient tapered wings can SFC-built slight increase time effort addition several layers silkspan usually required beef-up center thicker wider airfoil doing job instead results lighter overall model efficient well After years research development testing evaluation SFC concepts techniques convinced ever could eventually replace balsa wood long modelers approach open mind relative prices balsa foam reverse detailed SFC data special materials available directly author 3744 E Nye Lane Carson City NV 89701 Please send SASE inquiring FF Duration/Meuser Continued page 57 wing found formerly severe flutter problem virtually disappeared add ing diagonal ribs both increased torsional stiffness wing moved its CG forward difficult say effect turned trick Deluxe flufi~ dispenser use cattail fluffies thermal-detecting aid has become quite standard have habit making mess cute trick get upwind 126 Model Aviation Division B & B Industries Looking Hard Find Soaring Goodies Jfe &i4fane fT/acory o has complete comprehensive line R/G Soaring productstoeverexist North America o Our line products includesthosefrom some respected firms Europe well complete inventory own US manufacturers o We carry complete line Kits Hardware Accessories & Building Supplies have full inventory Launching Equipment & Related Products o We serve serious R/G soaring enthusiast supplies kits other items have sought long Call write today Free product listing & price sheet Sailplane Fcto717 244 4508 PO Box 34 Red Lion PA 173569am- 9pm EST PS Come see displays 1982 WRAMS & TOLEDO shows

MOST OF THE WORLDS BALSA supply being used super-tanker construction told Balsa still available additional demand has forced price up point us feel can no longer afford writer instance appalled balsa price situation 1978 discovered thatitwouldcost$22OOjusttobalsa-sheet anS foot glider wing Foam plastic has coming ever-greater use model construction during past few years current techniques still quite costly because involve use expensive surfac ing materialsbalsa thin plywood special film Such approaches addition being costly too heavy several modeling appli cations especially Free Flight What needed inexpensive way rigidiz ing foam plastic cores add needed strength adding much weight cost building time offer results three years research upon pages What pre sented essentially follow-up fine series articles Evans Lester appearing January-March 1978 issues MA Early research foam plastic experi menting common variety white expanded polystyrene Styrofoam sold lumberyards insulation comes various thick nesses 1 up either 2-or 4-ft wide 8 ft long material has density pound per cubic foot quite cheap problem material poly styrene foam easily dissolved glue dope paint found others have best compatible liquid materials white glue epoxy attempting first seal foam white glue top-coat dope result dope usually man aged find make break seal ruining job eating up foam Early attempts assumed structural rigidity required use supporting wooden structure Leading trailing edges spars some ribs therefore added foam core Besides being time-consuming adding weight expense such reinforcing structures found material future plank cast $270 will build several models new tech nique lightweight construction types modelsFF CL RCwhich promises easier cheaper just strong balsa Ron St Jean designed world-famous Ramrod FF Fifties has put years painstaking re search methods mater ials results interest builders U Ron St Jean totally unnecessary Adequate rigidity almost cases can achieved skin alone full-scale builders designers led Burt Rutan Vari-eze fame reinforcing foam successive layers glass cloth epoxy felt might cheaper easier less toxic cleaner method achiev ing similar result research utilized white glue aliphatic resin silkspan modeling paper structureless foam composites SFC proper techniques approach has proven completely competitive balsa wood terms almost Free-Flight contest work far superior balsa con struction respects such cost Although universally applicable phases model ing foam/silkspan/white-glue approach believed equally feasible FF CL RC models opinion may eventually replace much balsa now being used modeling Balsa/foam comparisons current prices cost making model airplane structure balsa several times using SFC tech nique described below Just strength balsa model may varied selecting wood different sizes densities same may done foam models changing number laminations silkapan use small hardwood plywood pieces and/or epoxy-coating points par ticularly high stress Just case balsa increasing strength foam results weight increases strength weight normal levels balsa foam comparable Constructing ones first foam model could take almost much time building balsa because one-time need make patterns slowness always accom panies learning patterns already avail able several SFC ships have made building time can drop about one-third balsa/tissue model breaks occur foam model merely needs epoxy pieces together results greater strength before break could break wing half instance flying again less half hour Repairing balsa models usually much time-consum ing requires steps process Further less likely get holes solid foam surface built-up balsa wing typical balsa models covering sags tween ribs sometimes spars too creat ing irregularities airflowwhich may reduce performance contours foam 50 Model Aviation rroving tne truction concept Salt Lake City Annual author son took home three first-place trophies two models shown built foam White glue doesnt protect voam trom dope two heavy coats glue didnt keep dope attacking foam panel model close designed factor certainly must contribute sensational performance Burt Rutans full-scale de signs would give foam FF model edge over comparable balsa ships fullscale sailplane field also foam replacing older construction methods because results Making patterns first used -in plywood lumberyard patterns Later made thin cardboard mat board sold art stores ideal purpose Wing stab templates should two piecesone bottom camber top thus split becomes possible include lead-in lead-out pattern portion pattern can accommodate hot wire both before after cutting foam pattern looks like finished airfoil necessary engage foam same time end work also nec essary hot wire depart same time end suppose lead-ins lead-outs provided continue camber angles wing LE TE have tolerance within side cutter can slightly lead lag other Result person can entire job long cutter short enough him control both ends same time bottom camber cut first stop blocks may added upper camber patterns order control wing thickness blocks April 1982 51 lower stab has wooden structure reinforcement w oz upper reinforced its glue/silkspan skin weighs four oz Lighter structure lust strong SFC has tried different types model airplanes foam-composite RC Sailplane gets running flight test improved performance Left author puts Scotsman 850 SFC model cold gray skies Right Leonard St Jean 020-powered Payload model beginning HOG attempt Model placed Nats register finished bottom camber Cutting bows wires power sources Evans/Lester bow described February 1978 issue MA very practical main advantages type automatic tension adjustment wire lengthened heating 52 Model Aviation contrast first bows rigid cutting wire expanded heat tension disappeared Sometimes attempting com pensate tightening wire within bow would either broken stretched utilizing variac variable transformer found nichrome wire necessary since lower voltage could used adjust lower resistance piano wire variac power supply feasible altema tives since easily adjusted differing lengths diameters wire needs to start zero voltage input foam cutter engage piece scrap foam wire turn up variac until wire first starts moving through foam Model train transformers have tried power sources dont have fine enough adjustment Check surplus electronics store variac 100 watts eonaro poses n uniimieo nuvue Juueehpoq Prop blades Unlimited Rubber ship cut block foam inserted special helical box Hub end right Simple Lennie St Jean launches fathersT-tailed A-This 1/2A beginners CL model designed 2 Nordic Glider entirely SFC-builtFrank Hamilton took pictures gaggle Hand-launched Gliders uses SFC wings rudders stabs hardwood fuselages Balsa tissue usually loses arguments witn sagebrush bushes SFC resists punctures set patterns SFC model can cut thin ply artists mat board mat board slightly less durable easier work Patterns shown Payload ship advantage small cutting wire its use results better surface finish have cut foam -in sheets having very smooth finish using solid 008 wire old CL reel Generally solid 012-015 diameter wire good average need nichrome variac used control voltage input lower heat put cutting wire better finish foam will Solid hollow construction FF models having fuselages small cross-section feasible approach appears to go solid way desirable have hollow fuselage can accomplished three ways fuselage may cut covered hollowed out desired gouging anything Moto Tool screwdriver dissolving unwanted foam solvent such gasoline two-piece fuselage right-and-left top-and-bottom halves could have its innards wire-cut away foam could cut sheets -in thick covered both sides assembled just model being made sheet balsa Sanding foam Some believe one-pound foam cannot sanded experience indicates new techniques special care needed weak spots located experience may beefed up additional thicknesses silkspan and/or epoxy coating epoxy especially useful securing wire hooks setting place uses epoxy would used balsa order provide larger pressure-distributing transitional area Without such hooks could torn loose high pressures must withstand have derived following rules thumb determine number thickness silkspan put FF Gas model use standard-weight silkspan GM anything much larger use heavier SGM material Small fuselages double-covered third layer around firewalls front stabil izer rubberbands go around Tails single-covered Small wings single-covered double covering center sections larger models constant-chord wings second covering may run half wayfrom center tip third layer goes about fourth distance edges reinforced overlapping layers instance wing leading edges LE have minimum two layers top covering bottom Should additional LE reinforce ment deemed necessary narrow strips silkspan may added over basic covering sand successfully techniques use sand balsa applied foam quickly ruin material new methods involves switching finer grits sandpaper plastic backing rough sanding * 150 paper about right using *280 finer finishing Grits coarser * 150 should used hogging out large chunks foam cannot wire cut Four precautions observed sanding foam 1 Apply much less pressure sanding wood 2 Immediately stop feel something rolling between sandpaper foam will small sphere loose foam will gouge scratch 3 Avoid bring ing folded edge sandpaper contact foam too will scratch gouge 4 Remove hard spots continue sanding Pick foam smooth begin troublesome hard spots will minimized Reinforcing foam Although silkspan covered foam adequate almost entire airplane few spots will require wood reinforce ment Generally same spots would use plywood balsa model firewalls landing-gear mounts timer mounts some mating surfaces parts rubberbanded together etc April 1982 53 fixture used cut foam needed sheet thickness Vertical board L adiustable blank-cutting bow can handle lengths up 36 cutting wire slides against patterns attached ends blank lttakestwo patternsto cut wing onetorthetop camberand forthe bottom Blocks register bottom camber control thickness Once blank cut bottom camber next Note leadins leadouts guide hot wire top camber almost finished Hot wire has already come through end jig used cutting dihedral angles front face adjustable Undercambered airfoils no problem panel almost compl~ accommodate angle Wet-covering foam silkapan easyjust dont dent foam pressing too hard Large models requiring greater strength require layers paper five six fuselage center constantchord wing two tail Covering fosm basic covering technique about same wet-covering solid surface silkspan trimmed paper dampened enough make fishy expand thinned white glue brushed through silkspan foam glue rubbed well work fingers symmetrically Continued page 118 54 Model Aviation early cutting bOwS ala adjust expansion wire heated allowing wire sag New ones maintain tension wire warms up ntld scrap duu garut uunny wIru wniu adjusting variac determine correct voltage Leading trailing edges reinforced overlapping edges top bottom sheets silkspan silkspan can added needed Half stab covered half Foam seems flimsy until after covered white glue silkapan strengthens tremendously minimal weight gain MASTER AIRSCRIW FLIGHTBOX KIT Master Airscrew Flight Box has features larger boxes compact handy arrangement parts cut imported mahogany plywood will take stain varnish paint finishes overall size 19Wx9%x 12 high $E 495 dealer Qor postpaid California add 6% Sales Tax FEATURES INCLUDE Space battery & meter panel Transmitter compartment Room gallon fuel Propeller storage Gravity closed small parts storage 7/8 aluminum handle Complete instructions & fasteners WINDSOR PROPELLER CO 384 Tesconi Ct Santa Rosa CA 95401 P/i llT5MFC SOOd 50C otIog RC Kits Mfgx I2 16 499-5323 IEAmL706 Easton NEX tKULcanton OH 44721 x seat eventually scale-like pilot achieve near perfect balance overall weight just over 4 lbs 7 oz Although reprints Crickets newsletter supplied included several tips improve service life correct minor problem areas clarify construction steps chose restrict head teeter avoid potential tail boom strikes main rotor other tips should tried necessity dictatesthe old aint broke dont fix philosophy applies significant problem Cricket owners having young children may encountered seat option addedhow keep pilot seat child says Can play doll Dad First flights large bolt taped seat nice finally get fly Cricket using own stick mode found very little difficulty getting things setup fact static set-up instruc tions yielded near perfect flight trims machine adjustment made after first lift-off blade tracking after tracking however experienced vibration during hovering flights believe due possible error adjustment tester spring coning angle vibration excessive however have made no attempt remedy date have received several letters regarding vibra tion problems number different types Helicopters perhaps subject timely Ill share subject comment further Cricket next month Dave Chesney Rt 9 Box 62 IA Greensboro NC 27409 RC Pylon Racing/Hager Continued page 49 would still spend three weeks finishing planes would lot other fliers should make tough new guys area couple years ago decided away scale judging just draw straws takeoff position first didnt like idea after couple years racing Ive changed mind After what interested doing want race put good finish airplane comments would appreciated Bill Hager 706 Glen Haven Dr Conroe TX 77302 SFC/St Jean Continued page 54 center tips bottom flat undercambered wings should covered first order better preserve airfoil design White glue thinned about 60% glue/40% water food coloring dye added dye colors work identifies glue voids spots no color Aliphatic resin thinned 50/50 refer mix Nudope Since covering shrinks upon drying wise either cover opposite side shortly after first almost dry redampen flatten just before doing second side order minimize warpage final product Should need remove warp add adjustment can easily accomplished heat An electric heater works finejust careful nbt melt foam structures however have memory tends show up very hot days better cut adjustments foam start feasible covered model sanded #150 regular paper before finishing adding addi 118 Model Aviation WARNING Tests have shown GloBee Glow Plugs habit forming Write TWinn-K Inc Dept GB3 Indianapolis Indiana 46231 FP THF RFRT IN RADIO CONTROL Id iUPoL U1IMUNN F7FTIGERCATSUPER HUNTER 6OSIZE ACRO TRAINER 40 SIZE DUCTED FAN F-lOG DELTA DART 0 FORMULA 1 HIGH PERFORMANCE PROPELLERS DIV AIRSCREW EACH PROPELLER HAND BALANCED Herd Eastern Maple Accurate airfoil pitch 44 C 858X65Rj 8s8X74i9 Additional propellers evailebla loxeJO CUSTOM DESIGN UPON REQUEST DISECT SALAS ONLY W PRODUCTS' IX postog handling SAXA CRYSTAL COUNT$150 FOR COD ond SANTA ROSA 54O4 CA PEA ADO N% TAX PSONE IYOl 528ROSA tional thicknesses paper Final hunildity-proof finish film used finish SFC model inexpensive can purchased grocery store quite light about -mu thickness easily quickly applied almost infinitely heat-shrinkable Saran Wrapnot original product fairly new called Freezing Microwave Saran Wrap few tips putting Put light coat spray adhesive structure covering large area feasible order minimize overlaps later masking eliminate glue spray finished work cause films heat-shrinking ability can entire top polyhedral wing Make sure adhesive fully set-up before adding Saran 3Ms *77 spray adhesive adequate Make certain solvent adhesive has evaporated before pressing plastic place Once film place rub work edges joints secure heatshrinking best done ordinary 250-watt heat lamp Just paint heat onto Saran being sure keep lamp moving no closer needed shrink film four five inches get too close tarry too long spot foam can melt little heat shrinking good idea hold film adjacent edge pulling away work will prevent its shrinking away edge work After area shrunk should immediately burnished foam surface Kleenex still hot permanent attachment Any entrapped air can gradually worked out Finally Saran trimmed new razor blade edges finished MonoKote iron low Continued page 126 taimt0 wset&e tiA CoS lbL4ed dO 14tIUThTL LflC April 1982 119 MIDWEST PRODUCTS COMPANY INC 400 S Indiana St Hobart Indiana 46342 219 942-1134 Send $100 catalog Look Future Product DeveIopmen Full Command Systems Manufacturers EK Logitrol radios accessories py eai Dealer Inquiries Welcome Full Command Systems 9O8ERo sewood Spokane WA 99207 . 509 487-2122 414 90 1 r CaQtcg213 76 JIceceggoktcgPO BOX R/C GOODIES 192 S VAN NUYS CA 91408I month 3uvdia offering SPECIAL PRICES several accessory items RegularI 1prices shown small tvoe BARGAIN PRICES shown heavy typeI VCAPS$895UNIVERSAL SERVO TRAY Hi Visibility 2Color Caps I match 72 MHz Freq Specify size fits 5289 AIR-FLO HINGES21 tray Bantam Connon N OCE3 CE4 CE5 Futaba Kraft KPS12 Midget servos1 mcMtg hardware included C Q FREQUENCY FLAGS j 051 Golden Bee etc Uses Iron Hinges easy chable holder1 standard 1/432 glow pluginstall Strips 36 Ig polyester ribbons $209SMALL 1iLARGE 1 1/2All Frec colors $169$149 $169I Urn$2500$169$199 VISA ORParts Ship 7 Calif add Soles Tax Catalog 604 MORE US $1 70 Foreign Add 4-1/2% Visor Master Cordj heat desired Saran film may painted inside prior application Most spray paint will work will look like expensive factory-painted -glued Mylar films small fraction cost Scotch Monocoat will exclude moisture better before painting Since F&M Saran Wrap softer Mylar does tend get scuffed up bit making landings hard sufface such spots turn up easily repaired bit 5-mm epoxy smeared bad spot might instead put piece Mylar over spot Conclusions seems ridiculous believe piece flimsy highly-flexible easilysquashed piece foam could stiffened given enough strength addition mere paper glue become competitive model airplane begins cover long thin wing instance first thought handling delicate coat might might well try cover wet noodle once foam has taken its paper clothing undergoes transforma tion unlike metamorphosis David Banner turning Hulk say proof pudding eating What will such model competi tion date foam fleet has won nine trophies five contests using first-generation hardware SFC approach has now used success fully several types FF models including Hand-Launched Gliders P-30 Coupe Un limited Rubber models A-i Towline Gliders catapult gliders well classes AMA Gas 020s through Class D SFC natural CL Combat wings perhaps 45 models built far three RC tremendous potential also especially Quarter Scale beginners FF gas model using reed-valve 049 has built successfully tested almost lost third flight will subject follow-up article soon appear pages have recently discovered inherentlymore-efficient tapered wings can SFC-built slight increase time effort addition several layers silkspan usually required beef-up center thicker wider airfoil doing job instead results lighter overall model efficient well After years research development testing evaluation SFC concepts techniques convinced ever could eventually replace balsa wood long modelers approach open mind relative prices balsa foam reverse detailed SFC data special materials available directly author 3744 E Nye Lane Carson City NV 89701 Please send SASE inquiring FF Duration/Meuser Continued page 57 wing found formerly severe flutter problem virtually disappeared add ing diagonal ribs both increased torsional stiffness wing moved its CG forward difficult say effect turned trick Deluxe flufi~ dispenser use cattail fluffies thermal-detecting aid has become quite standard have habit making mess cute trick get upwind 126 Model Aviation Division B & B Industries Looking Hard Find Soaring Goodies Jfe &i4fane fT/acory o has complete comprehensive line R/G Soaring productstoeverexist North America o Our line products includesthosefrom some respected firms Europe well complete inventory own US manufacturers o We carry complete line Kits Hardware Accessories & Building Supplies have full inventory Launching Equipment & Related Products o We serve serious R/G soaring enthusiast supplies kits other items have sought long Call write today Free product listing & price sheet Sailplane Fcto717 244 4508 PO Box 34 Red Lion PA 173569am- 9pm EST PS Come see displays 1982 WRAMS & TOLEDO shows