Navy Carrier THERE ARE factors contrib ute successful Carrier flightpilot skill engine performance airplane weather rank order Under 76-77 scoring system pilot skill has re placed engine important factor Without good landing hard competitive Pilot skill also affects low speed lesser extent high speed benefits practice improve low speed landing scores obvious Practice also helps achieving reliable consistent engine performance Reading magazine wont help improve pilot skills us can control weather very effectively Im going waste time writing about two factors am going write about engines airplanes next few months main goal series help new comer Carrier flying avoid some frustration rest us endured starting out event month topics carburetors fuel tanks emphasis Profile Carrier Profile models must use suction fuel system course since January 1976 have option using style carburetor desire lot has said various magazines about improve engine performance through proper break-in proper fit piston shaft proper timing etc very little has said about carburetor Most people content accept ques tion standard carburetor comes engine cases Fox Profile Carrier Special exception stock RC carbu retors designed small throat areas provide good fuel draw consistent engine runs under widely varying flight loads attitudes encountered RC flying Carrier flying engines must cope two conditions critical performancetakeoff level flight constant airspeed After takeoff high speed portion flight presents no problems uneven fuel draw fuel subjected consid erable centrifugal force force constant throughout high speed por tion flight Under condition small-throat carburetor high fuel draw needed long fuel tank appropriately positioned factor determines upper limit carburetor throat area acceleration occurs takeoff Carburetor throat area can enlarged until engine loses power takeoff engine already has problem difficulty may carburetor fuel tank Keep read ing Since difficult back up small er throat area after going too far will offer some suggestions based ex Richard 1 Peny TWA 36 engine Wallick Industries used Dave Wallick Dayton contest flight 2706 points now may available Below Before after ST 35 carb normally has 16 mm2 throat area top Reduced spray bar width yields 22 mm2 simple inexpensive performance increase perience feel throat area 22mm2 good compromise between power sensitivity fuel tank position 25mm2 intake can handle takeoff ac celeration little sensitive fuel tank position 30mm2 some problems acceleration occur fuel tank posi tion critical provide reference Supertigre ST 35 RC has throat area 16mm2 Fox Profile Carrier Special has throat area 29mm2 numerous ways increase throat area obvious solution crease size bore requires some careful machine work can overdone carburetor will close properly idle speed will suffer spray bar protrudes part way throat may shortened Some adjustable some must cut off spray bar continuous across bore may reduced width times carburetor intended larger engine may adapted smaller done Fox engine stock ST 35 carburetor has bore 75 mm 0295 spray bar 4mm 0157 wide accompanying photo graphs show effect reducing width spray bar spray bar width 3mm 0120 yields 22mm2 area modification worth 3-5 mph engines airplanes further reduc tion 255mm 0100 brings area up 25mm2 optimum high speed engine must run its best mixture during high speed run must go lean takeoff loses power secret good engine runs lies fuel tank line line must short pos siblelosses line reduce effec tive fuel draw engine Fuel lines must stiff enough resist bending possible kinking during acceleration high speed flight What determines load carbu retor must overcome direction magnitude acceleration force acting fuel distance parallel force between surface fuel tank hole spray bar Sitting ground acceleration force gravity straight down distance between fuel surface spray bar usually rather small As soon airplane released accelera tion force changes direction rear down about 600 angle grows about twice normal force gravity As model gains speed force gets stronger moves outward away center circle 85 mph force within 70 horizontal over eight times force gravity ideal fuel tank would put upper surface fuel spray bar ground air Fig 1 situation can hard achieve continued page 94 March 1977 41 ENGINE CYLINDER HEADQUARTERS SUITABLE FOR SCALE OR STAND-OFF MODELS AVAILABLE FOR IMMEDIATE DELIVERY Take hard work out radial engined models highly de f tailed cylinders precision molded high-impact styrene fea ture deep cooling fins SIZES Whirlwind 1 1 1/2PP 2 scales Le Rhone 1 1 1/2/P 2 scales Wasp 1 1 1/2P 2 scales LE RHONE Universal ales ALSO AVAILABLE MACHINE GUN KITS NERS E WHEELS TS 0 CANOPIES 181 PAWNEE STREET SAN MARCOS CALIFORNIA 9 PBA Special/Scott continued page 37 used connect innermost hole bellcrank outer hole flap horn elevators pushrod connects outer bellcrank hole elevator horn hole used should such travel elevator about three times opposition travel flaps Thus applying 450 UP elevator should result flaps being depressed about 150 use adjustable RC-type clevis fitting pushrods will greatly simplify setting up flaps Performance PBA Special will also enhanced fitting smaller wheels though done expense ground handling another lesson aeronautics practically design feature Aviation compro mise now again ready return aerodrome time Ad vanced trainer Advanced trainer will fly much Basic configuration did However larger wing wing flaps will allow model fly rather smoothly through maneuvers AMA Rule Book Precision Aerobatics can very demanding maneuvers accomplished contest stunt ships nothing combinations taught PBA Special take offs level flight loops wingovers inverted flight landing Thus under standing may proceed confidence area Control-line flying Happy landings lots ofem CL Navy Carrier/Perry continued page 47 standard Profile Carrier fuel tank mount ing unless tank partially full half-full tank however increases dis tance between fuel spray bar take off fuel goes back tank desired effect can obtained using uniflow tank uniflow tank has vent tube same mixture air ground fuel level should spray bar under both conditions FIGURE 2 FUEL TANK FOR PROFILE CARRIER EVEN WITI4 SPRAY BA 9 / / // K / -J Ii ii S FRONT fuel level engine sees point vent tube terminates within tank long vent im mersed fuel standard uniflow tank has vent tube near fuel pick-up point optimum Carrier cause causes greater apparent dis tance between fuel carburetor during acceleration apparent fuel level often outboard carburetor high speed tank use shown Fig 2 can adapted commercial squarewedge fuel tank must leak-proof fuel vent should near front tank spray bar look ing directly nose fill tank through vent airplane its nose separate vent tube use fill ing could added must plugged during flight having trouble engine runs being inconsistent using stock carburetor want increase engine output little expenditure time money give ideas try Richard L Perry 5016 Angelita Ave Dayton OH 45424 TOP VENT SIDE 94 Model Aviation 25t FOR COMPLETE CATALOG Dept MA 4 UNIVERSAL IS OUTSIDEFIGURE CIRCLE AT R[ST ACCEL FORCE IN FLIGHT - CK UP ENGINES COX/SANWA RIG SYSTEMS AIRTRONICS KITS Send complete catalog 1525 EWarner Ave Santa Ana CA 92702 HOBBIES -- --II -- .0 . . .- 0 %
Edition: Model Aviation - 1977/03
Page Numbers: 41, 94
Navy Carrier THERE ARE factors contrib ute successful Carrier flightpilot skill engine performance airplane weather rank order Under 76-77 scoring system pilot skill has re placed engine important factor Without good landing hard competitive Pilot skill also affects low speed lesser extent high speed benefits practice improve low speed landing scores obvious Practice also helps achieving reliable consistent engine performance Reading magazine wont help improve pilot skills us can control weather very effectively Im going waste time writing about two factors am going write about engines airplanes next few months main goal series help new comer Carrier flying avoid some frustration rest us endured starting out event month topics carburetors fuel tanks emphasis Profile Carrier Profile models must use suction fuel system course since January 1976 have option using style carburetor desire lot has said various magazines about improve engine performance through proper break-in proper fit piston shaft proper timing etc very little has said about carburetor Most people content accept ques tion standard carburetor comes engine cases Fox Profile Carrier Special exception stock RC carbu retors designed small throat areas provide good fuel draw consistent engine runs under widely varying flight loads attitudes encountered RC flying Carrier flying engines must cope two conditions critical performancetakeoff level flight constant airspeed After takeoff high speed portion flight presents no problems uneven fuel draw fuel subjected consid erable centrifugal force force constant throughout high speed por tion flight Under condition small-throat carburetor high fuel draw needed long fuel tank appropriately positioned factor determines upper limit carburetor throat area acceleration occurs takeoff Carburetor throat area can enlarged until engine loses power takeoff engine already has problem difficulty may carburetor fuel tank Keep read ing Since difficult back up small er throat area after going too far will offer some suggestions based ex Richard 1 Peny TWA 36 engine Wallick Industries used Dave Wallick Dayton contest flight 2706 points now may available Below Before after ST 35 carb normally has 16 mm2 throat area top Reduced spray bar width yields 22 mm2 simple inexpensive performance increase perience feel throat area 22mm2 good compromise between power sensitivity fuel tank position 25mm2 intake can handle takeoff ac celeration little sensitive fuel tank position 30mm2 some problems acceleration occur fuel tank posi tion critical provide reference Supertigre ST 35 RC has throat area 16mm2 Fox Profile Carrier Special has throat area 29mm2 numerous ways increase throat area obvious solution crease size bore requires some careful machine work can overdone carburetor will close properly idle speed will suffer spray bar protrudes part way throat may shortened Some adjustable some must cut off spray bar continuous across bore may reduced width times carburetor intended larger engine may adapted smaller done Fox engine stock ST 35 carburetor has bore 75 mm 0295 spray bar 4mm 0157 wide accompanying photo graphs show effect reducing width spray bar spray bar width 3mm 0120 yields 22mm2 area modification worth 3-5 mph engines airplanes further reduc tion 255mm 0100 brings area up 25mm2 optimum high speed engine must run its best mixture during high speed run must go lean takeoff loses power secret good engine runs lies fuel tank line line must short pos siblelosses line reduce effec tive fuel draw engine Fuel lines must stiff enough resist bending possible kinking during acceleration high speed flight What determines load carbu retor must overcome direction magnitude acceleration force acting fuel distance parallel force between surface fuel tank hole spray bar Sitting ground acceleration force gravity straight down distance between fuel surface spray bar usually rather small As soon airplane released accelera tion force changes direction rear down about 600 angle grows about twice normal force gravity As model gains speed force gets stronger moves outward away center circle 85 mph force within 70 horizontal over eight times force gravity ideal fuel tank would put upper surface fuel spray bar ground air Fig 1 situation can hard achieve continued page 94 March 1977 41 ENGINE CYLINDER HEADQUARTERS SUITABLE FOR SCALE OR STAND-OFF MODELS AVAILABLE FOR IMMEDIATE DELIVERY Take hard work out radial engined models highly de f tailed cylinders precision molded high-impact styrene fea ture deep cooling fins SIZES Whirlwind 1 1 1/2PP 2 scales Le Rhone 1 1 1/2/P 2 scales Wasp 1 1 1/2P 2 scales LE RHONE Universal ales ALSO AVAILABLE MACHINE GUN KITS NERS E WHEELS TS 0 CANOPIES 181 PAWNEE STREET SAN MARCOS CALIFORNIA 9 PBA Special/Scott continued page 37 used connect innermost hole bellcrank outer hole flap horn elevators pushrod connects outer bellcrank hole elevator horn hole used should such travel elevator about three times opposition travel flaps Thus applying 450 UP elevator should result flaps being depressed about 150 use adjustable RC-type clevis fitting pushrods will greatly simplify setting up flaps Performance PBA Special will also enhanced fitting smaller wheels though done expense ground handling another lesson aeronautics practically design feature Aviation compro mise now again ready return aerodrome time Ad vanced trainer Advanced trainer will fly much Basic configuration did However larger wing wing flaps will allow model fly rather smoothly through maneuvers AMA Rule Book Precision Aerobatics can very demanding maneuvers accomplished contest stunt ships nothing combinations taught PBA Special take offs level flight loops wingovers inverted flight landing Thus under standing may proceed confidence area Control-line flying Happy landings lots ofem CL Navy Carrier/Perry continued page 47 standard Profile Carrier fuel tank mount ing unless tank partially full half-full tank however increases dis tance between fuel spray bar take off fuel goes back tank desired effect can obtained using uniflow tank uniflow tank has vent tube same mixture air ground fuel level should spray bar under both conditions FIGURE 2 FUEL TANK FOR PROFILE CARRIER EVEN WITI4 SPRAY BA 9 / / // K / -J Ii ii S FRONT fuel level engine sees point vent tube terminates within tank long vent im mersed fuel standard uniflow tank has vent tube near fuel pick-up point optimum Carrier cause causes greater apparent dis tance between fuel carburetor during acceleration apparent fuel level often outboard carburetor high speed tank use shown Fig 2 can adapted commercial squarewedge fuel tank must leak-proof fuel vent should near front tank spray bar look ing directly nose fill tank through vent airplane its nose separate vent tube use fill ing could added must plugged during flight having trouble engine runs being inconsistent using stock carburetor want increase engine output little expenditure time money give ideas try Richard L Perry 5016 Angelita Ave Dayton OH 45424 TOP VENT SIDE 94 Model Aviation 25t FOR COMPLETE CATALOG Dept MA 4 UNIVERSAL IS OUTSIDEFIGURE CIRCLE AT R[ST ACCEL FORCE IN FLIGHT - CK UP ENGINES COX/SANWA RIG SYSTEMS AIRTRONICS KITS Send complete catalog 1525 EWarner Ave Santa Ana CA 92702 HOBBIES -- --II -- .0 . . .- 0 %