An array Supertigre-manufactured engines having various displacements porting combinations aii tesica inc three propeliers shown picture Table No 3 reports results kit suggests wide variety acceptable engine sIzes say 20 40 usually better use larger size throttle capability amount power can always reduced ntials TUNED PIPES refer exhaust sys tem tuned particular engine operating range ways tune exhaust two-cycle engine have used successfully model engines recollection Bill Wisniew3ki originator modern tuned pipe expansion chamber model engines least made popular circa 1966 Bills system used expansion cham ber amounted inlet pipe diverging nozzle taper inlet pipe connected converging taper very small outlet pipe dimensions systems carefully calculated tested provide maximum power Very basically tuned pipes utilize pressure waves present exhaust supercharge engine increases volumetric efficiency hence produc es power Expansion chambers generate maxi mum performance over narrow operat ing range rpms used specialty events such CL Speed RC boats some RC airplane record categories Currently three other popular 42 Model Aviation Magic Muffleron sport airplane Notethe connectortubing ana ineruci 8flK pressuretap Tuned pipes engine sizes rich lean fuel mixtures break-in pro cedures carbure tors idle settings discussed installment view helping get two-cycle model engine Part 2 John Kilsdonk exhaust tuning systems addition original Wisniewski expansion chamber second system tuned muffler amounts standard expansion chamber additional can over back system has wider operational band quite popular RC applica tions particularly RC Pattern third system called mini-pipe nothing short 3- 6in tuned length constant diameter pipe mini-pipe used some CL events Rat Race Formula 40 D Speed plus RC Formula Quarter Midget Pylon Racing Mini-pipes unlike other systems enhance rather abate exhaust noise suitable using exhaust pressure fuel supply Magic Mufflers fourth typea Typical Pylon Racer installation mini-pipe Quarter Midget Spring around cylinder holds olace mini-aloe Intensifies engine noise rather reducing version mini-pipe addition can reduced-diameter tail pipe noise suppression generate enough back pressure effective fuel system pressure Refer Figure No 3 schematic various tuned pipes should noted concurrent evolution model engine tuned pipes has similar development efforts other two-cycle engine applica tions maximum performance desired noticeably motorcycles go-karts proper application engine timing exhaust tuning given engine tuned exhaust can develop much 50% power although 15% 25% considered realistic dont want get TUNED PIPE ETh TUNED MUFFLER MATIC OF TUNED EXHAUSTS ZD 1 MINI PIPE FIGURE NO 3 DIRECTION OF FLOW MAGIC MUFFLER 0 APPROXIMATE SCALE Inch.L April 1985 43 23 technical necessary should made aware effective exhaust timing length function engine exhaust timing air density exhaust temperature rpm means normally cant just buy tuned exhaust system bolt engine Rather necessary tune system first rule tune system static ground rpm Generally inflight engine speed 500 1500 rpm higher ground rpm properly tuned racing models may several thousand rpm higher way tune system in-flight perform ance select size smaller prop will fly witha 9-6 10-5 instead 10-6 11-6 instead 11-7 etc smaller prop will approximate actual flying rpm engine ground Run engine maximum rpm smaller prop record rpm Next either shorten lengthen exhaust system about /2 re measure rpm engine speed went up youre going right direc tion went down went wrong way no detectable change probably close want Assuming saw increase keep go ing direction about A-in incre ments until quit making progress point should install flying prop fly model check inflight performance Helpful hints include making sure always readjust needle valve length change Actually changing length proper direc tion change will produce richer needle setting last volumetric efficiency increases sec ond hint cut material necessary header pipe attached engine expansion chamber third hint remember exhaust tun ing function air density dramatic temperature altitude changes encountered pipe length will have changed Similar length changes necessary drastic nitro changes fuel exhaust temperature affect wish venture deeply theories expansion chambers several articles particularly Wisniewski model engines published Model Airplane News 1966-67 also series Gordon Jennings motorcycle engine tuning Glenn Lee published update February 1979 Model Aviation EngIne sizes necessarily mean physical appearance weight engine Rather piston displace ment usually designated cubic inches such 15 25 40 60 etc Some engines designated cubic centi meters cc 1cc equals 061 cu Piston displacement determined using different micrometers measure cylinder bore diameter piston stroke sample 46 engine measured bore B 866 piston BDC measured 942 top cylinder top piston Similarly piston rotated TDC measured 163 top cylinder top piston calculated stroke 5 942 minus 163 779 calculate displacement formula 314 x B divided 22 x S sample engine measured displacement 314 x 866 divided 22x 779 cu Table No 3 shows relative perform ance various displacement engines same brands power affected increased displacement type porting used Correct engine size always dilemma modeler especially novice Nor mally compromise between price engine what will fit air plane confusion compounded kit manufacturers list wide range engine sizes particular model kit lists engine sizes 20 40 will probably fly very poorly 20 have choice always pick largest engine size listed particular model Remember cases Left Adjustments Irvine carburetor sliding barrel type used engines Right popular Perry carburetor its adjustments internal mix type idle adjusting different other brands nonetheless easy 44 Model Aviation Tuned muffler installation side-exhaust engine Pattern model Note sili cone tube connector between header pipealso pressure line fuel tank have throttle control speed additional power advantage should need windy day take off heavy grass Rich lean perhaps two troublesome buzzwords refer fuel mixture setting combustion proc esses require proper ratio fuel air applies process whether gas-fired furnace home igniting combustible liquid An open pan gasoline will ignite suf ficient oxygen air Please dont try though take word Internal combustion engines partic ular model engines no exception Normally range fuel-to-air ratios under particular fuel will ig nite Within range no optimum ideal condition known stoichiometric Rich means excess fuel amount available air Lean means excess air amount fuel available richen mixture needle valve turned Out normally counterclockwise allow fuel enter engine Lean leaner just opposite meaning turn needle clockwise restrict amount fuel Mixture setting changes can detected sound frequency change ground tachometer will enhance changes audio-only audio visual However tachometer nec essary cases achieve proper needle setting Before progressing how-to proper needle setting must define couple terms Actually talked about two-cycle four-cycle earlier need amplify buzzwords some As said earlier four-cycle engines have combustion process other revolution two-cycles fire revolution terms also descriptive needle valve settings two-cycle model engines rich needle setting produces slow gurgling sound lower frequency four-cycle sound called four-cycle setting As mixture leaned out frequency creases until crossover point reached sound frequency changes quite abruptly fine-tuned sound tach ometer may show thousand rpm change very slight needle valve movement crossover As needle turned further frequency will increase point sound will flatten out stoichiometric half turn will start slow down starts slow down needle turned over-lean word caution over-lean engine will die very rapid death doubt set richernever operate engine overlean few seconds very helpful technique recheck needle valve setting what call Charmin test think youve got needle set check quickly squeezing fuel supply line quick squeeze should produce audible crease engine speed dont hear increase back needle off open until little practice technique will find squeez ing-the-Charmin excellent cross check needle valve setting Continued page 141 Left 05 4A carb typIfies air bleed type Note small hole Idle mIxture control screw adjust air bleed Right ST Mag IV carb another sliding barrel types Adjusting similar Irvine Mag carbe front runners type carburetor April 1985 45 iunea muTtier installation rear-exnaust Pattern model Note SliP jOintTOriength timing Steve Helms904 478-6745 Al Featuring fast service qualified people latest equipment including SPECTRUM ANAL YZER AM FM SIGNAL GENERATOR Call Sam Leonard Tony Stiliman custom work competition needs stock complete hobby line specializing competition accessories discounted prices RADIO SOUTH- AUTHORIZED SERVICE CENTER FOR kruft Pro Line ie r- - bo JR 43 West Nine Mile Rd Pensacola FL 32514 * Futaba Distributor er Inquiries Welcome * correct flag ever correct first place have opportunity confusion Frequency flags accident looking place happen better nothing whole idea Red SRF flag page 128 Rule book cut down number frequency flag errors putting everything need right flag thereby making ridiculously easy mount proper information Due its distinctive size shape color colorblindness eliminated factors consideration Unfortunately cer tain AMA District VP seems unable understand problem Hes proba bly alone spite carryingon about uncertainties colors duplica tions colors numbers flags required difficulty learning understand ing 60 flags etc people prefer con tinuation old inefficient ways learning new better obvious thing Turn ON receiver before turn ON transmitE ng es/Ki sdo n k Continued page 45 Setting needle properly ground first step What really counts in-flight performance becomes somewhat difficult have depend sound also feel properly-tuned engine will slow down sag loops especially consecutive loops ex tended vertical maneuvers first sign sagging loss power retard throttle land open needle extended life service model engine prefer slightly rich nee dle setting can detect slight increase engine speed vertical maneu vers also allows model fly constant speed attitude ter may learn about someone channel interference before fly Dont fly before youve checked thing found 100o should Only birds ever have fly rest us can choose whether situation right flight Safe flight result planning checking testing beforehand get up start getting glitches throttle back land Weve seen far too experts crashed unnecessarily long after received first warning Sometimes glitches come ailerons have fluttered off servo arms have lost screws about jump off servo engines ready fall out rubberbands have failed cold about let wing go bye-bye hinges have pulled out similar disasters have nothing radios interferences Happy Landings George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Engine break-in olden days breaking-in model engine meant hooking up gallon fuel let ting run very rich several hours test stand end time probably nice piston-to-cylinder fit crank bushing well lapped connecting rod worn out Modern manufacturing technology re quires minimal break-in Piston/cylinder fits now controlled machining rather hand fitting lengthy wear-in Similarly cranks sup ported ball bearings now rule rather exception used carburetor-equipped engines rarely use test stand run-in engine anymore normal break-in procedure new engine usually done right airplane select propeller size smaller expect eventually use An example would 9-6 instead 10-6 11-6 instead 11-7 Whether reduction diameter pitch dependent will fly airplane best Open needle valve five six turns start engine about half throttle Let run three four minutes set ting gradually open throttle full point very slowly adjust needle valve progressively leaner ex act point four-cycle two-cycle transi tion back off quarter turn Check adjust idle point least acceptable should pointed out idle quality will improve after few flights final adjustments should made satisfied idle sufficient safely land airplane shut off engine refill fuel tank engine now ready in-flight break-in Dont think might just well get some flying breakingin engine sure beats watching engine run test stand Restart engine recheck both high-speed idle mixture settings doubt about high-speed setting run slightly rich Let takeoff full throttle once airplane safe comfortable altitude pull throttle back one-half three-quarters full full throttle will damage engine smaller prop will fully load should running slightly rich anyway Fly around like minute allowing engine cool itself go back full minute repeat cycle entire flight Repeat flight procedure cou ple flights gradually leaning out mixture until full power achieved After couple full-bore flights can fine-tune idle mixture April 1985 141 Still Using bid Fashioned L4/ing Hinges -rt~s GO gain control efficiency eliminating gap between moveable 2nd stationary control surfaces will amazed performance gained using simple inexpen sive improvement FREE MOVEMENT 450 STRONG AND LIGHTWEIGHT COMPLETELY FUELPROOF COMPATABLE WITH ALL IRON-ON MATERIALS COMES IN 3 PT LENGTHS SMALL 118 ORPRICE 3 ft $250 LARGE 114 Thats Some engines will break-in faster slower pro cedure good rule thumb Three flights cycling part full throttle another two full throttle about hours flying engine broken ready give hours enjoyable flying Now should install propeller proper size experiment various props opti mum performance engines equipped throttle special racing engine applications use test stand test prop smaller diameter carefully cut balanced larger prop preserve hub size strength Refer Table No 4 recommended dimensions test stand should provide very rigid mount engine weighted secured necessary prevent movement Fill fuel tank enough about five minutes running Make sure engine securely mounted install test prop Open needle valve five six turns start engine engine should running very rich high speed After minute gradually lean out mixture small increments until after about five minutes engine close two-cycle operation shut down engine refill fuel tank way have operated engine near in-flight rpmbut quite cool due rich mixture providing excess lubrication succeeding runs want cycle engine between two-cycle fourcycle settings 30-second increments Depending particular engine may take anywhere several EASY TO INSTALL i CUT I/4 DEEP SLIT ALLWG TIE FILL LEAIGrH DY TiE MATAG N/REACtS INSTALL HA//SE USE STRAIGHT PIN 10 AVAIVE SA84LL HOLE EVERY IICH OR SODR/P CYAM2ACRYLATE DUE IAI HOLESCAPLLARY ACF7DN WILL CARRY GLUE 41/kS/N EATI//E /ORIT FOR ADDITIOAI4L SEOAPITI 3 ASERT SS/ALL RIS EVERY FEW INCHES LVT OFF FLUSH FILL AND SAND AS NEEDED FOR FINISHING Send Free info fine products FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 runs engine wrn hold two-cycle setting two minutes noticeable sagging drop off power its ready fly Agaln what youve done run engine slightly above its ground rpm very cool absence normal prop load allows mating surfaces wear proper air rpm speeds Its good idea set engine slightly rich first few flights ensure complete break-in Idle settings Most modem engines equipped carburetor will idle consistently 2500 rpm below An idle speed 3000 rpm below quite satisfactory applications achieve good quality idle rather simple cases However necessary understand adjustments carburetor make sure glow plug good order should pointed out glow plugs have two failure modes com mon broken coil wire opens electrical circuit starting other failure just wear out properly become over-oxidized coil element becomes coated point still maintaining electrical conductivity heat transfer coil combustion mixture impeded point engine opera tion affected condition readily detected engine speed drops upon removal starting battery best rule thumb use new glow plug before trying set idle speeds Once done must also under stand function carburetor adjustments three principle carburetor types air bleed internal mix what call sliding barrel air bleed car buretor simplest addition high-speed main needle valve another yery small screw usually near small drilled hole front body screw turned-in clockwise CW restricts air bleed richening mixture Unscrewing counterclockwise CCW leans-out idle mixture allowing air bleed through drilled hole internal mix carburetor exempli fied very popular Perry idle mixture done internally con trolled large wheel main needle valve side carburetor large wheel has slot aligns mark carb body Either side slot wheel marked tating rds notch CW will richen idle mixture moving towards notch CCW will lean sliding barrel carb has rotating barrel barrel also moves axially needle valve idle mix ture control carbs second needle valve same axis directly opposite main valve needle rotated CW lean out CCW rich much same main needlebut far greater sensitivity adjustment carbs called idle stop screw con trols full-closed position barrel Personally never use Rather use radio throttle trim control closed position full trim full low throt tle set ideal idle pulling trim back way can kill engine Lets adjust idle mixture First make sure install known good new glow plug type recom mended engine first step open carb wide open throttle WOT Adjust highspeed main needle maximum perform ance close throttle far possi ble maintain minimum rpm Should engine die point usually idle mixture too far off have determine dying rich lean Restart engine go slightly higher rpm can maintain Slowly close throttle paying attention sound gurgles burps little prior dying too rich dies slowly usually its too lean Adjust idle mix ture screw according instructions above improve condition slowly methodically either leaning richening mixture improve con dition As condition improves keep reducing idle speed time As approach satisfactory idle speed engine will run longer longer time before dies Now time apply Dave Brown 142 Model Aviation GAPLESS HiNGE SLOTTER - Simplifies installation Gapless Hingas Makes 510114 Sizes Balsa CE $250 technique Dave premier Pattern flier taught following method several years ago After can get engine idle least five seconds before dying retard throttle high speed idle position pinch squeeze off fuel line engine quits sooner before its too lean runs longer its too rich Either way adjust idle mix ture screw needle valve accordingly CCW richen CW lean out adjust main needle Care should taken keep fingers and/or screwdrivers away prop also make minute adjustments never eighth turn time After adjustment keep checking progress make sure youre going right direction ensure havent gone too far satisfied readjust final idle position via throttle trim linkageor using idle stop carbto attain minimum reliable idle speed Thats key course understand what ing go about methodical manner Next month will conclude series discussion glow plugs props fuel care engine RC Aerobatics/Van Putte Continued page 47 tions provided alternative form competition traditional upwind downwind style Unfortunately Howard went say Finally writer Mowrey R VP ought reassured people care what thinks However believe should take time analyze F3A should flown before condemns may time far off RC Aerobatics will flown way Well certainly hope although understand rule proposal fly Turnaround classes competi tion Unfortunately always some people think its necessary junk what have order start something new Turnaround Pattern competition always available anyone wants compete rule bcok states competitors class may compete Turn around Contest Directors force competitors chcose between nor mal class Turnaround because allow ing compete both would either make contest too long cut number rounds flown course fliers normally fly Expert Masters usually win Turnaround tco thats probably what brought about new rules proposal have classes Turnaround Theres another topic reason Jim White called first place claims really arent lot RC Pattern fliers country got information dont know claims about 2500 Pattern fliers competed 1984 Fur ther less 150 contests average contest attendance about 20 Hows grab course theres way confirm claims AMA receives contest reports Contest Directors shouldnt take enormous effort go through reports analyze statistics hes right half members AMA RC fliers about 50000 about 5% RC fliers competed Pattern least once last year Thats small number people expend much time effort money know its strange thing Pattern competitor say think bears lcoking way believe five contests competed last year average 25 conI received letter Mark Corbett Route #2 Box 80-A Waxhaw NC 28173 regarding Pattern proposal called Super Seven letter part said Super Seven one-day Saturday Pattern meet would reduce time involved thus avoiding unnecessary motel fcod fuel costs well problems delayed Sunday fliers As its name reveals Super Seven provides seven-minute flight seven maneuvers everyone takeoff landing would count Expert above would perform touchand-go rest schedule could aligned suite AMA Contest Direc tor holding meet Turnaround-style pattern could use same type format Super Seven could flown Sundayperhaps pro-class event favor Turnaround can afford have spoken re garding idea Mark went say feel change needed believe would instill new life Pattern flying have personally flown models 22 years Pattern eight Masters class six eight cannot attend Pattern meets because time expense time has come really turnaround lcok ultimate goal Any response Super Seven proposal would appreciated Im sure Mark will get lot pro con responses us have drive long distance contests averaged 265 miles five contests last year would probably rather stay two days can afford time can appreciate reasoning one-day contest like describes Let him hear Id like congratulate Steve Rojecki publicly winning Tournament Champions Steve member club April 1985 143 testants
Edition: Model Aviation - 1985/04
Page Numbers: 42, 43, 44, 45, 141, 142, 143
An array Supertigre-manufactured engines having various displacements porting combinations aii tesica inc three propeliers shown picture Table No 3 reports results kit suggests wide variety acceptable engine sIzes say 20 40 usually better use larger size throttle capability amount power can always reduced ntials TUNED PIPES refer exhaust sys tem tuned particular engine operating range ways tune exhaust two-cycle engine have used successfully model engines recollection Bill Wisniew3ki originator modern tuned pipe expansion chamber model engines least made popular circa 1966 Bills system used expansion cham ber amounted inlet pipe diverging nozzle taper inlet pipe connected converging taper very small outlet pipe dimensions systems carefully calculated tested provide maximum power Very basically tuned pipes utilize pressure waves present exhaust supercharge engine increases volumetric efficiency hence produc es power Expansion chambers generate maxi mum performance over narrow operat ing range rpms used specialty events such CL Speed RC boats some RC airplane record categories Currently three other popular 42 Model Aviation Magic Muffleron sport airplane Notethe connectortubing ana ineruci 8flK pressuretap Tuned pipes engine sizes rich lean fuel mixtures break-in pro cedures carbure tors idle settings discussed installment view helping get two-cycle model engine Part 2 John Kilsdonk exhaust tuning systems addition original Wisniewski expansion chamber second system tuned muffler amounts standard expansion chamber additional can over back system has wider operational band quite popular RC applica tions particularly RC Pattern third system called mini-pipe nothing short 3- 6in tuned length constant diameter pipe mini-pipe used some CL events Rat Race Formula 40 D Speed plus RC Formula Quarter Midget Pylon Racing Mini-pipes unlike other systems enhance rather abate exhaust noise suitable using exhaust pressure fuel supply Magic Mufflers fourth typea Typical Pylon Racer installation mini-pipe Quarter Midget Spring around cylinder holds olace mini-aloe Intensifies engine noise rather reducing version mini-pipe addition can reduced-diameter tail pipe noise suppression generate enough back pressure effective fuel system pressure Refer Figure No 3 schematic various tuned pipes should noted concurrent evolution model engine tuned pipes has similar development efforts other two-cycle engine applica tions maximum performance desired noticeably motorcycles go-karts proper application engine timing exhaust tuning given engine tuned exhaust can develop much 50% power although 15% 25% considered realistic dont want get TUNED PIPE ETh TUNED MUFFLER MATIC OF TUNED EXHAUSTS ZD 1 MINI PIPE FIGURE NO 3 DIRECTION OF FLOW MAGIC MUFFLER 0 APPROXIMATE SCALE Inch.L April 1985 43 23 technical necessary should made aware effective exhaust timing length function engine exhaust timing air density exhaust temperature rpm means normally cant just buy tuned exhaust system bolt engine Rather necessary tune system first rule tune system static ground rpm Generally inflight engine speed 500 1500 rpm higher ground rpm properly tuned racing models may several thousand rpm higher way tune system in-flight perform ance select size smaller prop will fly witha 9-6 10-5 instead 10-6 11-6 instead 11-7 etc smaller prop will approximate actual flying rpm engine ground Run engine maximum rpm smaller prop record rpm Next either shorten lengthen exhaust system about /2 re measure rpm engine speed went up youre going right direc tion went down went wrong way no detectable change probably close want Assuming saw increase keep go ing direction about A-in incre ments until quit making progress point should install flying prop fly model check inflight performance Helpful hints include making sure always readjust needle valve length change Actually changing length proper direc tion change will produce richer needle setting last volumetric efficiency increases sec ond hint cut material necessary header pipe attached engine expansion chamber third hint remember exhaust tun ing function air density dramatic temperature altitude changes encountered pipe length will have changed Similar length changes necessary drastic nitro changes fuel exhaust temperature affect wish venture deeply theories expansion chambers several articles particularly Wisniewski model engines published Model Airplane News 1966-67 also series Gordon Jennings motorcycle engine tuning Glenn Lee published update February 1979 Model Aviation EngIne sizes necessarily mean physical appearance weight engine Rather piston displace ment usually designated cubic inches such 15 25 40 60 etc Some engines designated cubic centi meters cc 1cc equals 061 cu Piston displacement determined using different micrometers measure cylinder bore diameter piston stroke sample 46 engine measured bore B 866 piston BDC measured 942 top cylinder top piston Similarly piston rotated TDC measured 163 top cylinder top piston calculated stroke 5 942 minus 163 779 calculate displacement formula 314 x B divided 22 x S sample engine measured displacement 314 x 866 divided 22x 779 cu Table No 3 shows relative perform ance various displacement engines same brands power affected increased displacement type porting used Correct engine size always dilemma modeler especially novice Nor mally compromise between price engine what will fit air plane confusion compounded kit manufacturers list wide range engine sizes particular model kit lists engine sizes 20 40 will probably fly very poorly 20 have choice always pick largest engine size listed particular model Remember cases Left Adjustments Irvine carburetor sliding barrel type used engines Right popular Perry carburetor its adjustments internal mix type idle adjusting different other brands nonetheless easy 44 Model Aviation Tuned muffler installation side-exhaust engine Pattern model Note sili cone tube connector between header pipealso pressure line fuel tank have throttle control speed additional power advantage should need windy day take off heavy grass Rich lean perhaps two troublesome buzzwords refer fuel mixture setting combustion proc esses require proper ratio fuel air applies process whether gas-fired furnace home igniting combustible liquid An open pan gasoline will ignite suf ficient oxygen air Please dont try though take word Internal combustion engines partic ular model engines no exception Normally range fuel-to-air ratios under particular fuel will ig nite Within range no optimum ideal condition known stoichiometric Rich means excess fuel amount available air Lean means excess air amount fuel available richen mixture needle valve turned Out normally counterclockwise allow fuel enter engine Lean leaner just opposite meaning turn needle clockwise restrict amount fuel Mixture setting changes can detected sound frequency change ground tachometer will enhance changes audio-only audio visual However tachometer nec essary cases achieve proper needle setting Before progressing how-to proper needle setting must define couple terms Actually talked about two-cycle four-cycle earlier need amplify buzzwords some As said earlier four-cycle engines have combustion process other revolution two-cycles fire revolution terms also descriptive needle valve settings two-cycle model engines rich needle setting produces slow gurgling sound lower frequency four-cycle sound called four-cycle setting As mixture leaned out frequency creases until crossover point reached sound frequency changes quite abruptly fine-tuned sound tach ometer may show thousand rpm change very slight needle valve movement crossover As needle turned further frequency will increase point sound will flatten out stoichiometric half turn will start slow down starts slow down needle turned over-lean word caution over-lean engine will die very rapid death doubt set richernever operate engine overlean few seconds very helpful technique recheck needle valve setting what call Charmin test think youve got needle set check quickly squeezing fuel supply line quick squeeze should produce audible crease engine speed dont hear increase back needle off open until little practice technique will find squeez ing-the-Charmin excellent cross check needle valve setting Continued page 141 Left 05 4A carb typIfies air bleed type Note small hole Idle mIxture control screw adjust air bleed Right ST Mag IV carb another sliding barrel types Adjusting similar Irvine Mag carbe front runners type carburetor April 1985 45 iunea muTtier installation rear-exnaust Pattern model Note SliP jOintTOriength timing Steve Helms904 478-6745 Al Featuring fast service qualified people latest equipment including SPECTRUM ANAL YZER AM FM SIGNAL GENERATOR Call Sam Leonard Tony Stiliman custom work competition needs stock complete hobby line specializing competition accessories discounted prices RADIO SOUTH- AUTHORIZED SERVICE CENTER FOR kruft Pro Line ie r- - bo JR 43 West Nine Mile Rd Pensacola FL 32514 * Futaba Distributor er Inquiries Welcome * correct flag ever correct first place have opportunity confusion Frequency flags accident looking place happen better nothing whole idea Red SRF flag page 128 Rule book cut down number frequency flag errors putting everything need right flag thereby making ridiculously easy mount proper information Due its distinctive size shape color colorblindness eliminated factors consideration Unfortunately cer tain AMA District VP seems unable understand problem Hes proba bly alone spite carryingon about uncertainties colors duplica tions colors numbers flags required difficulty learning understand ing 60 flags etc people prefer con tinuation old inefficient ways learning new better obvious thing Turn ON receiver before turn ON transmitE ng es/Ki sdo n k Continued page 45 Setting needle properly ground first step What really counts in-flight performance becomes somewhat difficult have depend sound also feel properly-tuned engine will slow down sag loops especially consecutive loops ex tended vertical maneuvers first sign sagging loss power retard throttle land open needle extended life service model engine prefer slightly rich nee dle setting can detect slight increase engine speed vertical maneu vers also allows model fly constant speed attitude ter may learn about someone channel interference before fly Dont fly before youve checked thing found 100o should Only birds ever have fly rest us can choose whether situation right flight Safe flight result planning checking testing beforehand get up start getting glitches throttle back land Weve seen far too experts crashed unnecessarily long after received first warning Sometimes glitches come ailerons have fluttered off servo arms have lost screws about jump off servo engines ready fall out rubberbands have failed cold about let wing go bye-bye hinges have pulled out similar disasters have nothing radios interferences Happy Landings George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Engine break-in olden days breaking-in model engine meant hooking up gallon fuel let ting run very rich several hours test stand end time probably nice piston-to-cylinder fit crank bushing well lapped connecting rod worn out Modern manufacturing technology re quires minimal break-in Piston/cylinder fits now controlled machining rather hand fitting lengthy wear-in Similarly cranks sup ported ball bearings now rule rather exception used carburetor-equipped engines rarely use test stand run-in engine anymore normal break-in procedure new engine usually done right airplane select propeller size smaller expect eventually use An example would 9-6 instead 10-6 11-6 instead 11-7 Whether reduction diameter pitch dependent will fly airplane best Open needle valve five six turns start engine about half throttle Let run three four minutes set ting gradually open throttle full point very slowly adjust needle valve progressively leaner ex act point four-cycle two-cycle transi tion back off quarter turn Check adjust idle point least acceptable should pointed out idle quality will improve after few flights final adjustments should made satisfied idle sufficient safely land airplane shut off engine refill fuel tank engine now ready in-flight break-in Dont think might just well get some flying breakingin engine sure beats watching engine run test stand Restart engine recheck both high-speed idle mixture settings doubt about high-speed setting run slightly rich Let takeoff full throttle once airplane safe comfortable altitude pull throttle back one-half three-quarters full full throttle will damage engine smaller prop will fully load should running slightly rich anyway Fly around like minute allowing engine cool itself go back full minute repeat cycle entire flight Repeat flight procedure cou ple flights gradually leaning out mixture until full power achieved After couple full-bore flights can fine-tune idle mixture April 1985 141 Still Using bid Fashioned L4/ing Hinges -rt~s GO gain control efficiency eliminating gap between moveable 2nd stationary control surfaces will amazed performance gained using simple inexpen sive improvement FREE MOVEMENT 450 STRONG AND LIGHTWEIGHT COMPLETELY FUELPROOF COMPATABLE WITH ALL IRON-ON MATERIALS COMES IN 3 PT LENGTHS SMALL 118 ORPRICE 3 ft $250 LARGE 114 Thats Some engines will break-in faster slower pro cedure good rule thumb Three flights cycling part full throttle another two full throttle about hours flying engine broken ready give hours enjoyable flying Now should install propeller proper size experiment various props opti mum performance engines equipped throttle special racing engine applications use test stand test prop smaller diameter carefully cut balanced larger prop preserve hub size strength Refer Table No 4 recommended dimensions test stand should provide very rigid mount engine weighted secured necessary prevent movement Fill fuel tank enough about five minutes running Make sure engine securely mounted install test prop Open needle valve five six turns start engine engine should running very rich high speed After minute gradually lean out mixture small increments until after about five minutes engine close two-cycle operation shut down engine refill fuel tank way have operated engine near in-flight rpmbut quite cool due rich mixture providing excess lubrication succeeding runs want cycle engine between two-cycle fourcycle settings 30-second increments Depending particular engine may take anywhere several EASY TO INSTALL i CUT I/4 DEEP SLIT ALLWG TIE FILL LEAIGrH DY TiE MATAG N/REACtS INSTALL HA//SE USE STRAIGHT PIN 10 AVAIVE SA84LL HOLE EVERY IICH OR SODR/P CYAM2ACRYLATE DUE IAI HOLESCAPLLARY ACF7DN WILL CARRY GLUE 41/kS/N EATI//E /ORIT FOR ADDITIOAI4L SEOAPITI 3 ASERT SS/ALL RIS EVERY FEW INCHES LVT OFF FLUSH FILL AND SAND AS NEEDED FOR FINISHING Send Free info fine products FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 runs engine wrn hold two-cycle setting two minutes noticeable sagging drop off power its ready fly Agaln what youve done run engine slightly above its ground rpm very cool absence normal prop load allows mating surfaces wear proper air rpm speeds Its good idea set engine slightly rich first few flights ensure complete break-in Idle settings Most modem engines equipped carburetor will idle consistently 2500 rpm below An idle speed 3000 rpm below quite satisfactory applications achieve good quality idle rather simple cases However necessary understand adjustments carburetor make sure glow plug good order should pointed out glow plugs have two failure modes com mon broken coil wire opens electrical circuit starting other failure just wear out properly become over-oxidized coil element becomes coated point still maintaining electrical conductivity heat transfer coil combustion mixture impeded point engine opera tion affected condition readily detected engine speed drops upon removal starting battery best rule thumb use new glow plug before trying set idle speeds Once done must also under stand function carburetor adjustments three principle carburetor types air bleed internal mix what call sliding barrel air bleed car buretor simplest addition high-speed main needle valve another yery small screw usually near small drilled hole front body screw turned-in clockwise CW restricts air bleed richening mixture Unscrewing counterclockwise CCW leans-out idle mixture allowing air bleed through drilled hole internal mix carburetor exempli fied very popular Perry idle mixture done internally con trolled large wheel main needle valve side carburetor large wheel has slot aligns mark carb body Either side slot wheel marked tating rds notch CW will richen idle mixture moving towards notch CCW will lean sliding barrel carb has rotating barrel barrel also moves axially needle valve idle mix ture control carbs second needle valve same axis directly opposite main valve needle rotated CW lean out CCW rich much same main needlebut far greater sensitivity adjustment carbs called idle stop screw con trols full-closed position barrel Personally never use Rather use radio throttle trim control closed position full trim full low throt tle set ideal idle pulling trim back way can kill engine Lets adjust idle mixture First make sure install known good new glow plug type recom mended engine first step open carb wide open throttle WOT Adjust highspeed main needle maximum perform ance close throttle far possi ble maintain minimum rpm Should engine die point usually idle mixture too far off have determine dying rich lean Restart engine go slightly higher rpm can maintain Slowly close throttle paying attention sound gurgles burps little prior dying too rich dies slowly usually its too lean Adjust idle mix ture screw according instructions above improve condition slowly methodically either leaning richening mixture improve con dition As condition improves keep reducing idle speed time As approach satisfactory idle speed engine will run longer longer time before dies Now time apply Dave Brown 142 Model Aviation GAPLESS HiNGE SLOTTER - Simplifies installation Gapless Hingas Makes 510114 Sizes Balsa CE $250 technique Dave premier Pattern flier taught following method several years ago After can get engine idle least five seconds before dying retard throttle high speed idle position pinch squeeze off fuel line engine quits sooner before its too lean runs longer its too rich Either way adjust idle mix ture screw needle valve accordingly CCW richen CW lean out adjust main needle Care should taken keep fingers and/or screwdrivers away prop also make minute adjustments never eighth turn time After adjustment keep checking progress make sure youre going right direction ensure havent gone too far satisfied readjust final idle position via throttle trim linkageor using idle stop carbto attain minimum reliable idle speed Thats key course understand what ing go about methodical manner Next month will conclude series discussion glow plugs props fuel care engine RC Aerobatics/Van Putte Continued page 47 tions provided alternative form competition traditional upwind downwind style Unfortunately Howard went say Finally writer Mowrey R VP ought reassured people care what thinks However believe should take time analyze F3A should flown before condemns may time far off RC Aerobatics will flown way Well certainly hope although understand rule proposal fly Turnaround classes competi tion Unfortunately always some people think its necessary junk what have order start something new Turnaround Pattern competition always available anyone wants compete rule bcok states competitors class may compete Turn around Contest Directors force competitors chcose between nor mal class Turnaround because allow ing compete both would either make contest too long cut number rounds flown course fliers normally fly Expert Masters usually win Turnaround tco thats probably what brought about new rules proposal have classes Turnaround Theres another topic reason Jim White called first place claims really arent lot RC Pattern fliers country got information dont know claims about 2500 Pattern fliers competed 1984 Fur ther less 150 contests average contest attendance about 20 Hows grab course theres way confirm claims AMA receives contest reports Contest Directors shouldnt take enormous effort go through reports analyze statistics hes right half members AMA RC fliers about 50000 about 5% RC fliers competed Pattern least once last year Thats small number people expend much time effort money know its strange thing Pattern competitor say think bears lcoking way believe five contests competed last year average 25 conI received letter Mark Corbett Route #2 Box 80-A Waxhaw NC 28173 regarding Pattern proposal called Super Seven letter part said Super Seven one-day Saturday Pattern meet would reduce time involved thus avoiding unnecessary motel fcod fuel costs well problems delayed Sunday fliers As its name reveals Super Seven provides seven-minute flight seven maneuvers everyone takeoff landing would count Expert above would perform touchand-go rest schedule could aligned suite AMA Contest Direc tor holding meet Turnaround-style pattern could use same type format Super Seven could flown Sundayperhaps pro-class event favor Turnaround can afford have spoken re garding idea Mark went say feel change needed believe would instill new life Pattern flying have personally flown models 22 years Pattern eight Masters class six eight cannot attend Pattern meets because time expense time has come really turnaround lcok ultimate goal Any response Super Seven proposal would appreciated Im sure Mark will get lot pro con responses us have drive long distance contests averaged 265 miles five contests last year would probably rather stay two days can afford time can appreciate reasoning one-day contest like describes Let him hear Id like congratulate Steve Rojecki publicly winning Tournament Champions Steve member club April 1985 143 testants
Edition: Model Aviation - 1985/04
Page Numbers: 42, 43, 44, 45, 141, 142, 143
An array Supertigre-manufactured engines having various displacements porting combinations aii tesica inc three propeliers shown picture Table No 3 reports results kit suggests wide variety acceptable engine sIzes say 20 40 usually better use larger size throttle capability amount power can always reduced ntials TUNED PIPES refer exhaust sys tem tuned particular engine operating range ways tune exhaust two-cycle engine have used successfully model engines recollection Bill Wisniew3ki originator modern tuned pipe expansion chamber model engines least made popular circa 1966 Bills system used expansion cham ber amounted inlet pipe diverging nozzle taper inlet pipe connected converging taper very small outlet pipe dimensions systems carefully calculated tested provide maximum power Very basically tuned pipes utilize pressure waves present exhaust supercharge engine increases volumetric efficiency hence produc es power Expansion chambers generate maxi mum performance over narrow operat ing range rpms used specialty events such CL Speed RC boats some RC airplane record categories Currently three other popular 42 Model Aviation Magic Muffleron sport airplane Notethe connectortubing ana ineruci 8flK pressuretap Tuned pipes engine sizes rich lean fuel mixtures break-in pro cedures carbure tors idle settings discussed installment view helping get two-cycle model engine Part 2 John Kilsdonk exhaust tuning systems addition original Wisniewski expansion chamber second system tuned muffler amounts standard expansion chamber additional can over back system has wider operational band quite popular RC applica tions particularly RC Pattern third system called mini-pipe nothing short 3- 6in tuned length constant diameter pipe mini-pipe used some CL events Rat Race Formula 40 D Speed plus RC Formula Quarter Midget Pylon Racing Mini-pipes unlike other systems enhance rather abate exhaust noise suitable using exhaust pressure fuel supply Magic Mufflers fourth typea Typical Pylon Racer installation mini-pipe Quarter Midget Spring around cylinder holds olace mini-aloe Intensifies engine noise rather reducing version mini-pipe addition can reduced-diameter tail pipe noise suppression generate enough back pressure effective fuel system pressure Refer Figure No 3 schematic various tuned pipes should noted concurrent evolution model engine tuned pipes has similar development efforts other two-cycle engine applica tions maximum performance desired noticeably motorcycles go-karts proper application engine timing exhaust tuning given engine tuned exhaust can develop much 50% power although 15% 25% considered realistic dont want get TUNED PIPE ETh TUNED MUFFLER MATIC OF TUNED EXHAUSTS ZD 1 MINI PIPE FIGURE NO 3 DIRECTION OF FLOW MAGIC MUFFLER 0 APPROXIMATE SCALE Inch.L April 1985 43 23 technical necessary should made aware effective exhaust timing length function engine exhaust timing air density exhaust temperature rpm means normally cant just buy tuned exhaust system bolt engine Rather necessary tune system first rule tune system static ground rpm Generally inflight engine speed 500 1500 rpm higher ground rpm properly tuned racing models may several thousand rpm higher way tune system in-flight perform ance select size smaller prop will fly witha 9-6 10-5 instead 10-6 11-6 instead 11-7 etc smaller prop will approximate actual flying rpm engine ground Run engine maximum rpm smaller prop record rpm Next either shorten lengthen exhaust system about /2 re measure rpm engine speed went up youre going right direc tion went down went wrong way no detectable change probably close want Assuming saw increase keep go ing direction about A-in incre ments until quit making progress point should install flying prop fly model check inflight performance Helpful hints include making sure always readjust needle valve length change Actually changing length proper direc tion change will produce richer needle setting last volumetric efficiency increases sec ond hint cut material necessary header pipe attached engine expansion chamber third hint remember exhaust tun ing function air density dramatic temperature altitude changes encountered pipe length will have changed Similar length changes necessary drastic nitro changes fuel exhaust temperature affect wish venture deeply theories expansion chambers several articles particularly Wisniewski model engines published Model Airplane News 1966-67 also series Gordon Jennings motorcycle engine tuning Glenn Lee published update February 1979 Model Aviation EngIne sizes necessarily mean physical appearance weight engine Rather piston displace ment usually designated cubic inches such 15 25 40 60 etc Some engines designated cubic centi meters cc 1cc equals 061 cu Piston displacement determined using different micrometers measure cylinder bore diameter piston stroke sample 46 engine measured bore B 866 piston BDC measured 942 top cylinder top piston Similarly piston rotated TDC measured 163 top cylinder top piston calculated stroke 5 942 minus 163 779 calculate displacement formula 314 x B divided 22 x S sample engine measured displacement 314 x 866 divided 22x 779 cu Table No 3 shows relative perform ance various displacement engines same brands power affected increased displacement type porting used Correct engine size always dilemma modeler especially novice Nor mally compromise between price engine what will fit air plane confusion compounded kit manufacturers list wide range engine sizes particular model kit lists engine sizes 20 40 will probably fly very poorly 20 have choice always pick largest engine size listed particular model Remember cases Left Adjustments Irvine carburetor sliding barrel type used engines Right popular Perry carburetor its adjustments internal mix type idle adjusting different other brands nonetheless easy 44 Model Aviation Tuned muffler installation side-exhaust engine Pattern model Note sili cone tube connector between header pipealso pressure line fuel tank have throttle control speed additional power advantage should need windy day take off heavy grass Rich lean perhaps two troublesome buzzwords refer fuel mixture setting combustion proc esses require proper ratio fuel air applies process whether gas-fired furnace home igniting combustible liquid An open pan gasoline will ignite suf ficient oxygen air Please dont try though take word Internal combustion engines partic ular model engines no exception Normally range fuel-to-air ratios under particular fuel will ig nite Within range no optimum ideal condition known stoichiometric Rich means excess fuel amount available air Lean means excess air amount fuel available richen mixture needle valve turned Out normally counterclockwise allow fuel enter engine Lean leaner just opposite meaning turn needle clockwise restrict amount fuel Mixture setting changes can detected sound frequency change ground tachometer will enhance changes audio-only audio visual However tachometer nec essary cases achieve proper needle setting Before progressing how-to proper needle setting must define couple terms Actually talked about two-cycle four-cycle earlier need amplify buzzwords some As said earlier four-cycle engines have combustion process other revolution two-cycles fire revolution terms also descriptive needle valve settings two-cycle model engines rich needle setting produces slow gurgling sound lower frequency four-cycle sound called four-cycle setting As mixture leaned out frequency creases until crossover point reached sound frequency changes quite abruptly fine-tuned sound tach ometer may show thousand rpm change very slight needle valve movement crossover As needle turned further frequency will increase point sound will flatten out stoichiometric half turn will start slow down starts slow down needle turned over-lean word caution over-lean engine will die very rapid death doubt set richernever operate engine overlean few seconds very helpful technique recheck needle valve setting what call Charmin test think youve got needle set check quickly squeezing fuel supply line quick squeeze should produce audible crease engine speed dont hear increase back needle off open until little practice technique will find squeez ing-the-Charmin excellent cross check needle valve setting Continued page 141 Left 05 4A carb typIfies air bleed type Note small hole Idle mIxture control screw adjust air bleed Right ST Mag IV carb another sliding barrel types Adjusting similar Irvine Mag carbe front runners type carburetor April 1985 45 iunea muTtier installation rear-exnaust Pattern model Note SliP jOintTOriength timing Steve Helms904 478-6745 Al Featuring fast service qualified people latest equipment including SPECTRUM ANAL YZER AM FM SIGNAL GENERATOR Call Sam Leonard Tony Stiliman custom work competition needs stock complete hobby line specializing competition accessories discounted prices RADIO SOUTH- AUTHORIZED SERVICE CENTER FOR kruft Pro Line ie r- - bo JR 43 West Nine Mile Rd Pensacola FL 32514 * Futaba Distributor er Inquiries Welcome * correct flag ever correct first place have opportunity confusion Frequency flags accident looking place happen better nothing whole idea Red SRF flag page 128 Rule book cut down number frequency flag errors putting everything need right flag thereby making ridiculously easy mount proper information Due its distinctive size shape color colorblindness eliminated factors consideration Unfortunately cer tain AMA District VP seems unable understand problem Hes proba bly alone spite carryingon about uncertainties colors duplica tions colors numbers flags required difficulty learning understand ing 60 flags etc people prefer con tinuation old inefficient ways learning new better obvious thing Turn ON receiver before turn ON transmitE ng es/Ki sdo n k Continued page 45 Setting needle properly ground first step What really counts in-flight performance becomes somewhat difficult have depend sound also feel properly-tuned engine will slow down sag loops especially consecutive loops ex tended vertical maneuvers first sign sagging loss power retard throttle land open needle extended life service model engine prefer slightly rich nee dle setting can detect slight increase engine speed vertical maneu vers also allows model fly constant speed attitude ter may learn about someone channel interference before fly Dont fly before youve checked thing found 100o should Only birds ever have fly rest us can choose whether situation right flight Safe flight result planning checking testing beforehand get up start getting glitches throttle back land Weve seen far too experts crashed unnecessarily long after received first warning Sometimes glitches come ailerons have fluttered off servo arms have lost screws about jump off servo engines ready fall out rubberbands have failed cold about let wing go bye-bye hinges have pulled out similar disasters have nothing radios interferences Happy Landings George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Engine break-in olden days breaking-in model engine meant hooking up gallon fuel let ting run very rich several hours test stand end time probably nice piston-to-cylinder fit crank bushing well lapped connecting rod worn out Modern manufacturing technology re quires minimal break-in Piston/cylinder fits now controlled machining rather hand fitting lengthy wear-in Similarly cranks sup ported ball bearings now rule rather exception used carburetor-equipped engines rarely use test stand run-in engine anymore normal break-in procedure new engine usually done right airplane select propeller size smaller expect eventually use An example would 9-6 instead 10-6 11-6 instead 11-7 Whether reduction diameter pitch dependent will fly airplane best Open needle valve five six turns start engine about half throttle Let run three four minutes set ting gradually open throttle full point very slowly adjust needle valve progressively leaner ex act point four-cycle two-cycle transi tion back off quarter turn Check adjust idle point least acceptable should pointed out idle quality will improve after few flights final adjustments should made satisfied idle sufficient safely land airplane shut off engine refill fuel tank engine now ready in-flight break-in Dont think might just well get some flying breakingin engine sure beats watching engine run test stand Restart engine recheck both high-speed idle mixture settings doubt about high-speed setting run slightly rich Let takeoff full throttle once airplane safe comfortable altitude pull throttle back one-half three-quarters full full throttle will damage engine smaller prop will fully load should running slightly rich anyway Fly around like minute allowing engine cool itself go back full minute repeat cycle entire flight Repeat flight procedure cou ple flights gradually leaning out mixture until full power achieved After couple full-bore flights can fine-tune idle mixture April 1985 141 Still Using bid Fashioned L4/ing Hinges -rt~s GO gain control efficiency eliminating gap between moveable 2nd stationary control surfaces will amazed performance gained using simple inexpen sive improvement FREE MOVEMENT 450 STRONG AND LIGHTWEIGHT COMPLETELY FUELPROOF COMPATABLE WITH ALL IRON-ON MATERIALS COMES IN 3 PT LENGTHS SMALL 118 ORPRICE 3 ft $250 LARGE 114 Thats Some engines will break-in faster slower pro cedure good rule thumb Three flights cycling part full throttle another two full throttle about hours flying engine broken ready give hours enjoyable flying Now should install propeller proper size experiment various props opti mum performance engines equipped throttle special racing engine applications use test stand test prop smaller diameter carefully cut balanced larger prop preserve hub size strength Refer Table No 4 recommended dimensions test stand should provide very rigid mount engine weighted secured necessary prevent movement Fill fuel tank enough about five minutes running Make sure engine securely mounted install test prop Open needle valve five six turns start engine engine should running very rich high speed After minute gradually lean out mixture small increments until after about five minutes engine close two-cycle operation shut down engine refill fuel tank way have operated engine near in-flight rpmbut quite cool due rich mixture providing excess lubrication succeeding runs want cycle engine between two-cycle fourcycle settings 30-second increments Depending particular engine may take anywhere several EASY TO INSTALL i CUT I/4 DEEP SLIT ALLWG TIE FILL LEAIGrH DY TiE MATAG N/REACtS INSTALL HA//SE USE STRAIGHT PIN 10 AVAIVE SA84LL HOLE EVERY IICH OR SODR/P CYAM2ACRYLATE DUE IAI HOLESCAPLLARY ACF7DN WILL CARRY GLUE 41/kS/N EATI//E /ORIT FOR ADDITIOAI4L SEOAPITI 3 ASERT SS/ALL RIS EVERY FEW INCHES LVT OFF FLUSH FILL AND SAND AS NEEDED FOR FINISHING Send Free info fine products FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 runs engine wrn hold two-cycle setting two minutes noticeable sagging drop off power its ready fly Agaln what youve done run engine slightly above its ground rpm very cool absence normal prop load allows mating surfaces wear proper air rpm speeds Its good idea set engine slightly rich first few flights ensure complete break-in Idle settings Most modem engines equipped carburetor will idle consistently 2500 rpm below An idle speed 3000 rpm below quite satisfactory applications achieve good quality idle rather simple cases However necessary understand adjustments carburetor make sure glow plug good order should pointed out glow plugs have two failure modes com mon broken coil wire opens electrical circuit starting other failure just wear out properly become over-oxidized coil element becomes coated point still maintaining electrical conductivity heat transfer coil combustion mixture impeded point engine opera tion affected condition readily detected engine speed drops upon removal starting battery best rule thumb use new glow plug before trying set idle speeds Once done must also under stand function carburetor adjustments three principle carburetor types air bleed internal mix what call sliding barrel air bleed car buretor simplest addition high-speed main needle valve another yery small screw usually near small drilled hole front body screw turned-in clockwise CW restricts air bleed richening mixture Unscrewing counterclockwise CCW leans-out idle mixture allowing air bleed through drilled hole internal mix carburetor exempli fied very popular Perry idle mixture done internally con trolled large wheel main needle valve side carburetor large wheel has slot aligns mark carb body Either side slot wheel marked tating rds notch CW will richen idle mixture moving towards notch CCW will lean sliding barrel carb has rotating barrel barrel also moves axially needle valve idle mix ture control carbs second needle valve same axis directly opposite main valve needle rotated CW lean out CCW rich much same main needlebut far greater sensitivity adjustment carbs called idle stop screw con trols full-closed position barrel Personally never use Rather use radio throttle trim control closed position full trim full low throt tle set ideal idle pulling trim back way can kill engine Lets adjust idle mixture First make sure install known good new glow plug type recom mended engine first step open carb wide open throttle WOT Adjust highspeed main needle maximum perform ance close throttle far possi ble maintain minimum rpm Should engine die point usually idle mixture too far off have determine dying rich lean Restart engine go slightly higher rpm can maintain Slowly close throttle paying attention sound gurgles burps little prior dying too rich dies slowly usually its too lean Adjust idle mix ture screw according instructions above improve condition slowly methodically either leaning richening mixture improve con dition As condition improves keep reducing idle speed time As approach satisfactory idle speed engine will run longer longer time before dies Now time apply Dave Brown 142 Model Aviation GAPLESS HiNGE SLOTTER - Simplifies installation Gapless Hingas Makes 510114 Sizes Balsa CE $250 technique Dave premier Pattern flier taught following method several years ago After can get engine idle least five seconds before dying retard throttle high speed idle position pinch squeeze off fuel line engine quits sooner before its too lean runs longer its too rich Either way adjust idle mix ture screw needle valve accordingly CCW richen CW lean out adjust main needle Care should taken keep fingers and/or screwdrivers away prop also make minute adjustments never eighth turn time After adjustment keep checking progress make sure youre going right direction ensure havent gone too far satisfied readjust final idle position via throttle trim linkageor using idle stop carbto attain minimum reliable idle speed Thats key course understand what ing go about methodical manner Next month will conclude series discussion glow plugs props fuel care engine RC Aerobatics/Van Putte Continued page 47 tions provided alternative form competition traditional upwind downwind style Unfortunately Howard went say Finally writer Mowrey R VP ought reassured people care what thinks However believe should take time analyze F3A should flown before condemns may time far off RC Aerobatics will flown way Well certainly hope although understand rule proposal fly Turnaround classes competi tion Unfortunately always some people think its necessary junk what have order start something new Turnaround Pattern competition always available anyone wants compete rule bcok states competitors class may compete Turn around Contest Directors force competitors chcose between nor mal class Turnaround because allow ing compete both would either make contest too long cut number rounds flown course fliers normally fly Expert Masters usually win Turnaround tco thats probably what brought about new rules proposal have classes Turnaround Theres another topic reason Jim White called first place claims really arent lot RC Pattern fliers country got information dont know claims about 2500 Pattern fliers competed 1984 Fur ther less 150 contests average contest attendance about 20 Hows grab course theres way confirm claims AMA receives contest reports Contest Directors shouldnt take enormous effort go through reports analyze statistics hes right half members AMA RC fliers about 50000 about 5% RC fliers competed Pattern least once last year Thats small number people expend much time effort money know its strange thing Pattern competitor say think bears lcoking way believe five contests competed last year average 25 conI received letter Mark Corbett Route #2 Box 80-A Waxhaw NC 28173 regarding Pattern proposal called Super Seven letter part said Super Seven one-day Saturday Pattern meet would reduce time involved thus avoiding unnecessary motel fcod fuel costs well problems delayed Sunday fliers As its name reveals Super Seven provides seven-minute flight seven maneuvers everyone takeoff landing would count Expert above would perform touchand-go rest schedule could aligned suite AMA Contest Direc tor holding meet Turnaround-style pattern could use same type format Super Seven could flown Sundayperhaps pro-class event favor Turnaround can afford have spoken re garding idea Mark went say feel change needed believe would instill new life Pattern flying have personally flown models 22 years Pattern eight Masters class six eight cannot attend Pattern meets because time expense time has come really turnaround lcok ultimate goal Any response Super Seven proposal would appreciated Im sure Mark will get lot pro con responses us have drive long distance contests averaged 265 miles five contests last year would probably rather stay two days can afford time can appreciate reasoning one-day contest like describes Let him hear Id like congratulate Steve Rojecki publicly winning Tournament Champions Steve member club April 1985 143 testants
Edition: Model Aviation - 1985/04
Page Numbers: 42, 43, 44, 45, 141, 142, 143
An array Supertigre-manufactured engines having various displacements porting combinations aii tesica inc three propeliers shown picture Table No 3 reports results kit suggests wide variety acceptable engine sIzes say 20 40 usually better use larger size throttle capability amount power can always reduced ntials TUNED PIPES refer exhaust sys tem tuned particular engine operating range ways tune exhaust two-cycle engine have used successfully model engines recollection Bill Wisniew3ki originator modern tuned pipe expansion chamber model engines least made popular circa 1966 Bills system used expansion cham ber amounted inlet pipe diverging nozzle taper inlet pipe connected converging taper very small outlet pipe dimensions systems carefully calculated tested provide maximum power Very basically tuned pipes utilize pressure waves present exhaust supercharge engine increases volumetric efficiency hence produc es power Expansion chambers generate maxi mum performance over narrow operat ing range rpms used specialty events such CL Speed RC boats some RC airplane record categories Currently three other popular 42 Model Aviation Magic Muffleron sport airplane Notethe connectortubing ana ineruci 8flK pressuretap Tuned pipes engine sizes rich lean fuel mixtures break-in pro cedures carbure tors idle settings discussed installment view helping get two-cycle model engine Part 2 John Kilsdonk exhaust tuning systems addition original Wisniewski expansion chamber second system tuned muffler amounts standard expansion chamber additional can over back system has wider operational band quite popular RC applica tions particularly RC Pattern third system called mini-pipe nothing short 3- 6in tuned length constant diameter pipe mini-pipe used some CL events Rat Race Formula 40 D Speed plus RC Formula Quarter Midget Pylon Racing Mini-pipes unlike other systems enhance rather abate exhaust noise suitable using exhaust pressure fuel supply Magic Mufflers fourth typea Typical Pylon Racer installation mini-pipe Quarter Midget Spring around cylinder holds olace mini-aloe Intensifies engine noise rather reducing version mini-pipe addition can reduced-diameter tail pipe noise suppression generate enough back pressure effective fuel system pressure Refer Figure No 3 schematic various tuned pipes should noted concurrent evolution model engine tuned pipes has similar development efforts other two-cycle engine applica tions maximum performance desired noticeably motorcycles go-karts proper application engine timing exhaust tuning given engine tuned exhaust can develop much 50% power although 15% 25% considered realistic dont want get TUNED PIPE ETh TUNED MUFFLER MATIC OF TUNED EXHAUSTS ZD 1 MINI PIPE FIGURE NO 3 DIRECTION OF FLOW MAGIC MUFFLER 0 APPROXIMATE SCALE Inch.L April 1985 43 23 technical necessary should made aware effective exhaust timing length function engine exhaust timing air density exhaust temperature rpm means normally cant just buy tuned exhaust system bolt engine Rather necessary tune system first rule tune system static ground rpm Generally inflight engine speed 500 1500 rpm higher ground rpm properly tuned racing models may several thousand rpm higher way tune system in-flight perform ance select size smaller prop will fly witha 9-6 10-5 instead 10-6 11-6 instead 11-7 etc smaller prop will approximate actual flying rpm engine ground Run engine maximum rpm smaller prop record rpm Next either shorten lengthen exhaust system about /2 re measure rpm engine speed went up youre going right direc tion went down went wrong way no detectable change probably close want Assuming saw increase keep go ing direction about A-in incre ments until quit making progress point should install flying prop fly model check inflight performance Helpful hints include making sure always readjust needle valve length change Actually changing length proper direc tion change will produce richer needle setting last volumetric efficiency increases sec ond hint cut material necessary header pipe attached engine expansion chamber third hint remember exhaust tun ing function air density dramatic temperature altitude changes encountered pipe length will have changed Similar length changes necessary drastic nitro changes fuel exhaust temperature affect wish venture deeply theories expansion chambers several articles particularly Wisniewski model engines published Model Airplane News 1966-67 also series Gordon Jennings motorcycle engine tuning Glenn Lee published update February 1979 Model Aviation EngIne sizes necessarily mean physical appearance weight engine Rather piston displace ment usually designated cubic inches such 15 25 40 60 etc Some engines designated cubic centi meters cc 1cc equals 061 cu Piston displacement determined using different micrometers measure cylinder bore diameter piston stroke sample 46 engine measured bore B 866 piston BDC measured 942 top cylinder top piston Similarly piston rotated TDC measured 163 top cylinder top piston calculated stroke 5 942 minus 163 779 calculate displacement formula 314 x B divided 22 x S sample engine measured displacement 314 x 866 divided 22x 779 cu Table No 3 shows relative perform ance various displacement engines same brands power affected increased displacement type porting used Correct engine size always dilemma modeler especially novice Nor mally compromise between price engine what will fit air plane confusion compounded kit manufacturers list wide range engine sizes particular model kit lists engine sizes 20 40 will probably fly very poorly 20 have choice always pick largest engine size listed particular model Remember cases Left Adjustments Irvine carburetor sliding barrel type used engines Right popular Perry carburetor its adjustments internal mix type idle adjusting different other brands nonetheless easy 44 Model Aviation Tuned muffler installation side-exhaust engine Pattern model Note sili cone tube connector between header pipealso pressure line fuel tank have throttle control speed additional power advantage should need windy day take off heavy grass Rich lean perhaps two troublesome buzzwords refer fuel mixture setting combustion proc esses require proper ratio fuel air applies process whether gas-fired furnace home igniting combustible liquid An open pan gasoline will ignite suf ficient oxygen air Please dont try though take word Internal combustion engines partic ular model engines no exception Normally range fuel-to-air ratios under particular fuel will ig nite Within range no optimum ideal condition known stoichiometric Rich means excess fuel amount available air Lean means excess air amount fuel available richen mixture needle valve turned Out normally counterclockwise allow fuel enter engine Lean leaner just opposite meaning turn needle clockwise restrict amount fuel Mixture setting changes can detected sound frequency change ground tachometer will enhance changes audio-only audio visual However tachometer nec essary cases achieve proper needle setting Before progressing how-to proper needle setting must define couple terms Actually talked about two-cycle four-cycle earlier need amplify buzzwords some As said earlier four-cycle engines have combustion process other revolution two-cycles fire revolution terms also descriptive needle valve settings two-cycle model engines rich needle setting produces slow gurgling sound lower frequency four-cycle sound called four-cycle setting As mixture leaned out frequency creases until crossover point reached sound frequency changes quite abruptly fine-tuned sound tach ometer may show thousand rpm change very slight needle valve movement crossover As needle turned further frequency will increase point sound will flatten out stoichiometric half turn will start slow down starts slow down needle turned over-lean word caution over-lean engine will die very rapid death doubt set richernever operate engine overlean few seconds very helpful technique recheck needle valve setting what call Charmin test think youve got needle set check quickly squeezing fuel supply line quick squeeze should produce audible crease engine speed dont hear increase back needle off open until little practice technique will find squeez ing-the-Charmin excellent cross check needle valve setting Continued page 141 Left 05 4A carb typIfies air bleed type Note small hole Idle mIxture control screw adjust air bleed Right ST Mag IV carb another sliding barrel types Adjusting similar Irvine Mag carbe front runners type carburetor April 1985 45 iunea muTtier installation rear-exnaust Pattern model Note SliP jOintTOriength timing Steve Helms904 478-6745 Al Featuring fast service qualified people latest equipment including SPECTRUM ANAL YZER AM FM SIGNAL GENERATOR Call Sam Leonard Tony Stiliman custom work competition needs stock complete hobby line specializing competition accessories discounted prices RADIO SOUTH- AUTHORIZED SERVICE CENTER FOR kruft Pro Line ie r- - bo JR 43 West Nine Mile Rd Pensacola FL 32514 * Futaba Distributor er Inquiries Welcome * correct flag ever correct first place have opportunity confusion Frequency flags accident looking place happen better nothing whole idea Red SRF flag page 128 Rule book cut down number frequency flag errors putting everything need right flag thereby making ridiculously easy mount proper information Due its distinctive size shape color colorblindness eliminated factors consideration Unfortunately cer tain AMA District VP seems unable understand problem Hes proba bly alone spite carryingon about uncertainties colors duplica tions colors numbers flags required difficulty learning understand ing 60 flags etc people prefer con tinuation old inefficient ways learning new better obvious thing Turn ON receiver before turn ON transmitE ng es/Ki sdo n k Continued page 45 Setting needle properly ground first step What really counts in-flight performance becomes somewhat difficult have depend sound also feel properly-tuned engine will slow down sag loops especially consecutive loops ex tended vertical maneuvers first sign sagging loss power retard throttle land open needle extended life service model engine prefer slightly rich nee dle setting can detect slight increase engine speed vertical maneu vers also allows model fly constant speed attitude ter may learn about someone channel interference before fly Dont fly before youve checked thing found 100o should Only birds ever have fly rest us can choose whether situation right flight Safe flight result planning checking testing beforehand get up start getting glitches throttle back land Weve seen far too experts crashed unnecessarily long after received first warning Sometimes glitches come ailerons have fluttered off servo arms have lost screws about jump off servo engines ready fall out rubberbands have failed cold about let wing go bye-bye hinges have pulled out similar disasters have nothing radios interferences Happy Landings George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Engine break-in olden days breaking-in model engine meant hooking up gallon fuel let ting run very rich several hours test stand end time probably nice piston-to-cylinder fit crank bushing well lapped connecting rod worn out Modern manufacturing technology re quires minimal break-in Piston/cylinder fits now controlled machining rather hand fitting lengthy wear-in Similarly cranks sup ported ball bearings now rule rather exception used carburetor-equipped engines rarely use test stand run-in engine anymore normal break-in procedure new engine usually done right airplane select propeller size smaller expect eventually use An example would 9-6 instead 10-6 11-6 instead 11-7 Whether reduction diameter pitch dependent will fly airplane best Open needle valve five six turns start engine about half throttle Let run three four minutes set ting gradually open throttle full point very slowly adjust needle valve progressively leaner ex act point four-cycle two-cycle transi tion back off quarter turn Check adjust idle point least acceptable should pointed out idle quality will improve after few flights final adjustments should made satisfied idle sufficient safely land airplane shut off engine refill fuel tank engine now ready in-flight break-in Dont think might just well get some flying breakingin engine sure beats watching engine run test stand Restart engine recheck both high-speed idle mixture settings doubt about high-speed setting run slightly rich Let takeoff full throttle once airplane safe comfortable altitude pull throttle back one-half three-quarters full full throttle will damage engine smaller prop will fully load should running slightly rich anyway Fly around like minute allowing engine cool itself go back full minute repeat cycle entire flight Repeat flight procedure cou ple flights gradually leaning out mixture until full power achieved After couple full-bore flights can fine-tune idle mixture April 1985 141 Still Using bid Fashioned L4/ing Hinges -rt~s GO gain control efficiency eliminating gap between moveable 2nd stationary control surfaces will amazed performance gained using simple inexpen sive improvement FREE MOVEMENT 450 STRONG AND LIGHTWEIGHT COMPLETELY FUELPROOF COMPATABLE WITH ALL IRON-ON MATERIALS COMES IN 3 PT LENGTHS SMALL 118 ORPRICE 3 ft $250 LARGE 114 Thats Some engines will break-in faster slower pro cedure good rule thumb Three flights cycling part full throttle another two full throttle about hours flying engine broken ready give hours enjoyable flying Now should install propeller proper size experiment various props opti mum performance engines equipped throttle special racing engine applications use test stand test prop smaller diameter carefully cut balanced larger prop preserve hub size strength Refer Table No 4 recommended dimensions test stand should provide very rigid mount engine weighted secured necessary prevent movement Fill fuel tank enough about five minutes running Make sure engine securely mounted install test prop Open needle valve five six turns start engine engine should running very rich high speed After minute gradually lean out mixture small increments until after about five minutes engine close two-cycle operation shut down engine refill fuel tank way have operated engine near in-flight rpmbut quite cool due rich mixture providing excess lubrication succeeding runs want cycle engine between two-cycle fourcycle settings 30-second increments Depending particular engine may take anywhere several EASY TO INSTALL i CUT I/4 DEEP SLIT ALLWG TIE FILL LEAIGrH DY TiE MATAG N/REACtS INSTALL HA//SE USE STRAIGHT PIN 10 AVAIVE SA84LL HOLE EVERY IICH OR SODR/P CYAM2ACRYLATE DUE IAI HOLESCAPLLARY ACF7DN WILL CARRY GLUE 41/kS/N EATI//E /ORIT FOR ADDITIOAI4L SEOAPITI 3 ASERT SS/ALL RIS EVERY FEW INCHES LVT OFF FLUSH FILL AND SAND AS NEEDED FOR FINISHING Send Free info fine products FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 runs engine wrn hold two-cycle setting two minutes noticeable sagging drop off power its ready fly Agaln what youve done run engine slightly above its ground rpm very cool absence normal prop load allows mating surfaces wear proper air rpm speeds Its good idea set engine slightly rich first few flights ensure complete break-in Idle settings Most modem engines equipped carburetor will idle consistently 2500 rpm below An idle speed 3000 rpm below quite satisfactory applications achieve good quality idle rather simple cases However necessary understand adjustments carburetor make sure glow plug good order should pointed out glow plugs have two failure modes com mon broken coil wire opens electrical circuit starting other failure just wear out properly become over-oxidized coil element becomes coated point still maintaining electrical conductivity heat transfer coil combustion mixture impeded point engine opera tion affected condition readily detected engine speed drops upon removal starting battery best rule thumb use new glow plug before trying set idle speeds Once done must also under stand function carburetor adjustments three principle carburetor types air bleed internal mix what call sliding barrel air bleed car buretor simplest addition high-speed main needle valve another yery small screw usually near small drilled hole front body screw turned-in clockwise CW restricts air bleed richening mixture Unscrewing counterclockwise CCW leans-out idle mixture allowing air bleed through drilled hole internal mix carburetor exempli fied very popular Perry idle mixture done internally con trolled large wheel main needle valve side carburetor large wheel has slot aligns mark carb body Either side slot wheel marked tating rds notch CW will richen idle mixture moving towards notch CCW will lean sliding barrel carb has rotating barrel barrel also moves axially needle valve idle mix ture control carbs second needle valve same axis directly opposite main valve needle rotated CW lean out CCW rich much same main needlebut far greater sensitivity adjustment carbs called idle stop screw con trols full-closed position barrel Personally never use Rather use radio throttle trim control closed position full trim full low throt tle set ideal idle pulling trim back way can kill engine Lets adjust idle mixture First make sure install known good new glow plug type recom mended engine first step open carb wide open throttle WOT Adjust highspeed main needle maximum perform ance close throttle far possi ble maintain minimum rpm Should engine die point usually idle mixture too far off have determine dying rich lean Restart engine go slightly higher rpm can maintain Slowly close throttle paying attention sound gurgles burps little prior dying too rich dies slowly usually its too lean Adjust idle mix ture screw according instructions above improve condition slowly methodically either leaning richening mixture improve con dition As condition improves keep reducing idle speed time As approach satisfactory idle speed engine will run longer longer time before dies Now time apply Dave Brown 142 Model Aviation GAPLESS HiNGE SLOTTER - Simplifies installation Gapless Hingas Makes 510114 Sizes Balsa CE $250 technique Dave premier Pattern flier taught following method several years ago After can get engine idle least five seconds before dying retard throttle high speed idle position pinch squeeze off fuel line engine quits sooner before its too lean runs longer its too rich Either way adjust idle mix ture screw needle valve accordingly CCW richen CW lean out adjust main needle Care should taken keep fingers and/or screwdrivers away prop also make minute adjustments never eighth turn time After adjustment keep checking progress make sure youre going right direction ensure havent gone too far satisfied readjust final idle position via throttle trim linkageor using idle stop carbto attain minimum reliable idle speed Thats key course understand what ing go about methodical manner Next month will conclude series discussion glow plugs props fuel care engine RC Aerobatics/Van Putte Continued page 47 tions provided alternative form competition traditional upwind downwind style Unfortunately Howard went say Finally writer Mowrey R VP ought reassured people care what thinks However believe should take time analyze F3A should flown before condemns may time far off RC Aerobatics will flown way Well certainly hope although understand rule proposal fly Turnaround classes competi tion Unfortunately always some people think its necessary junk what have order start something new Turnaround Pattern competition always available anyone wants compete rule bcok states competitors class may compete Turn around Contest Directors force competitors chcose between nor mal class Turnaround because allow ing compete both would either make contest too long cut number rounds flown course fliers normally fly Expert Masters usually win Turnaround tco thats probably what brought about new rules proposal have classes Turnaround Theres another topic reason Jim White called first place claims really arent lot RC Pattern fliers country got information dont know claims about 2500 Pattern fliers competed 1984 Fur ther less 150 contests average contest attendance about 20 Hows grab course theres way confirm claims AMA receives contest reports Contest Directors shouldnt take enormous effort go through reports analyze statistics hes right half members AMA RC fliers about 50000 about 5% RC fliers competed Pattern least once last year Thats small number people expend much time effort money know its strange thing Pattern competitor say think bears lcoking way believe five contests competed last year average 25 conI received letter Mark Corbett Route #2 Box 80-A Waxhaw NC 28173 regarding Pattern proposal called Super Seven letter part said Super Seven one-day Saturday Pattern meet would reduce time involved thus avoiding unnecessary motel fcod fuel costs well problems delayed Sunday fliers As its name reveals Super Seven provides seven-minute flight seven maneuvers everyone takeoff landing would count Expert above would perform touchand-go rest schedule could aligned suite AMA Contest Direc tor holding meet Turnaround-style pattern could use same type format Super Seven could flown Sundayperhaps pro-class event favor Turnaround can afford have spoken re garding idea Mark went say feel change needed believe would instill new life Pattern flying have personally flown models 22 years Pattern eight Masters class six eight cannot attend Pattern meets because time expense time has come really turnaround lcok ultimate goal Any response Super Seven proposal would appreciated Im sure Mark will get lot pro con responses us have drive long distance contests averaged 265 miles five contests last year would probably rather stay two days can afford time can appreciate reasoning one-day contest like describes Let him hear Id like congratulate Steve Rojecki publicly winning Tournament Champions Steve member club April 1985 143 testants
Edition: Model Aviation - 1985/04
Page Numbers: 42, 43, 44, 45, 141, 142, 143
An array Supertigre-manufactured engines having various displacements porting combinations aii tesica inc three propeliers shown picture Table No 3 reports results kit suggests wide variety acceptable engine sIzes say 20 40 usually better use larger size throttle capability amount power can always reduced ntials TUNED PIPES refer exhaust sys tem tuned particular engine operating range ways tune exhaust two-cycle engine have used successfully model engines recollection Bill Wisniew3ki originator modern tuned pipe expansion chamber model engines least made popular circa 1966 Bills system used expansion cham ber amounted inlet pipe diverging nozzle taper inlet pipe connected converging taper very small outlet pipe dimensions systems carefully calculated tested provide maximum power Very basically tuned pipes utilize pressure waves present exhaust supercharge engine increases volumetric efficiency hence produc es power Expansion chambers generate maxi mum performance over narrow operat ing range rpms used specialty events such CL Speed RC boats some RC airplane record categories Currently three other popular 42 Model Aviation Magic Muffleron sport airplane Notethe connectortubing ana ineruci 8flK pressuretap Tuned pipes engine sizes rich lean fuel mixtures break-in pro cedures carbure tors idle settings discussed installment view helping get two-cycle model engine Part 2 John Kilsdonk exhaust tuning systems addition original Wisniewski expansion chamber second system tuned muffler amounts standard expansion chamber additional can over back system has wider operational band quite popular RC applica tions particularly RC Pattern third system called mini-pipe nothing short 3- 6in tuned length constant diameter pipe mini-pipe used some CL events Rat Race Formula 40 D Speed plus RC Formula Quarter Midget Pylon Racing Mini-pipes unlike other systems enhance rather abate exhaust noise suitable using exhaust pressure fuel supply Magic Mufflers fourth typea Typical Pylon Racer installation mini-pipe Quarter Midget Spring around cylinder holds olace mini-aloe Intensifies engine noise rather reducing version mini-pipe addition can reduced-diameter tail pipe noise suppression generate enough back pressure effective fuel system pressure Refer Figure No 3 schematic various tuned pipes should noted concurrent evolution model engine tuned pipes has similar development efforts other two-cycle engine applica tions maximum performance desired noticeably motorcycles go-karts proper application engine timing exhaust tuning given engine tuned exhaust can develop much 50% power although 15% 25% considered realistic dont want get TUNED PIPE ETh TUNED MUFFLER MATIC OF TUNED EXHAUSTS ZD 1 MINI PIPE FIGURE NO 3 DIRECTION OF FLOW MAGIC MUFFLER 0 APPROXIMATE SCALE Inch.L April 1985 43 23 technical necessary should made aware effective exhaust timing length function engine exhaust timing air density exhaust temperature rpm means normally cant just buy tuned exhaust system bolt engine Rather necessary tune system first rule tune system static ground rpm Generally inflight engine speed 500 1500 rpm higher ground rpm properly tuned racing models may several thousand rpm higher way tune system in-flight perform ance select size smaller prop will fly witha 9-6 10-5 instead 10-6 11-6 instead 11-7 etc smaller prop will approximate actual flying rpm engine ground Run engine maximum rpm smaller prop record rpm Next either shorten lengthen exhaust system about /2 re measure rpm engine speed went up youre going right direc tion went down went wrong way no detectable change probably close want Assuming saw increase keep go ing direction about A-in incre ments until quit making progress point should install flying prop fly model check inflight performance Helpful hints include making sure always readjust needle valve length change Actually changing length proper direc tion change will produce richer needle setting last volumetric efficiency increases sec ond hint cut material necessary header pipe attached engine expansion chamber third hint remember exhaust tun ing function air density dramatic temperature altitude changes encountered pipe length will have changed Similar length changes necessary drastic nitro changes fuel exhaust temperature affect wish venture deeply theories expansion chambers several articles particularly Wisniewski model engines published Model Airplane News 1966-67 also series Gordon Jennings motorcycle engine tuning Glenn Lee published update February 1979 Model Aviation EngIne sizes necessarily mean physical appearance weight engine Rather piston displace ment usually designated cubic inches such 15 25 40 60 etc Some engines designated cubic centi meters cc 1cc equals 061 cu Piston displacement determined using different micrometers measure cylinder bore diameter piston stroke sample 46 engine measured bore B 866 piston BDC measured 942 top cylinder top piston Similarly piston rotated TDC measured 163 top cylinder top piston calculated stroke 5 942 minus 163 779 calculate displacement formula 314 x B divided 22 x S sample engine measured displacement 314 x 866 divided 22x 779 cu Table No 3 shows relative perform ance various displacement engines same brands power affected increased displacement type porting used Correct engine size always dilemma modeler especially novice Nor mally compromise between price engine what will fit air plane confusion compounded kit manufacturers list wide range engine sizes particular model kit lists engine sizes 20 40 will probably fly very poorly 20 have choice always pick largest engine size listed particular model Remember cases Left Adjustments Irvine carburetor sliding barrel type used engines Right popular Perry carburetor its adjustments internal mix type idle adjusting different other brands nonetheless easy 44 Model Aviation Tuned muffler installation side-exhaust engine Pattern model Note sili cone tube connector between header pipealso pressure line fuel tank have throttle control speed additional power advantage should need windy day take off heavy grass Rich lean perhaps two troublesome buzzwords refer fuel mixture setting combustion proc esses require proper ratio fuel air applies process whether gas-fired furnace home igniting combustible liquid An open pan gasoline will ignite suf ficient oxygen air Please dont try though take word Internal combustion engines partic ular model engines no exception Normally range fuel-to-air ratios under particular fuel will ig nite Within range no optimum ideal condition known stoichiometric Rich means excess fuel amount available air Lean means excess air amount fuel available richen mixture needle valve turned Out normally counterclockwise allow fuel enter engine Lean leaner just opposite meaning turn needle clockwise restrict amount fuel Mixture setting changes can detected sound frequency change ground tachometer will enhance changes audio-only audio visual However tachometer nec essary cases achieve proper needle setting Before progressing how-to proper needle setting must define couple terms Actually talked about two-cycle four-cycle earlier need amplify buzzwords some As said earlier four-cycle engines have combustion process other revolution two-cycles fire revolution terms also descriptive needle valve settings two-cycle model engines rich needle setting produces slow gurgling sound lower frequency four-cycle sound called four-cycle setting As mixture leaned out frequency creases until crossover point reached sound frequency changes quite abruptly fine-tuned sound tach ometer may show thousand rpm change very slight needle valve movement crossover As needle turned further frequency will increase point sound will flatten out stoichiometric half turn will start slow down starts slow down needle turned over-lean word caution over-lean engine will die very rapid death doubt set richernever operate engine overlean few seconds very helpful technique recheck needle valve setting what call Charmin test think youve got needle set check quickly squeezing fuel supply line quick squeeze should produce audible crease engine speed dont hear increase back needle off open until little practice technique will find squeez ing-the-Charmin excellent cross check needle valve setting Continued page 141 Left 05 4A carb typIfies air bleed type Note small hole Idle mIxture control screw adjust air bleed Right ST Mag IV carb another sliding barrel types Adjusting similar Irvine Mag carbe front runners type carburetor April 1985 45 iunea muTtier installation rear-exnaust Pattern model Note SliP jOintTOriength timing Steve Helms904 478-6745 Al Featuring fast service qualified people latest equipment including SPECTRUM ANAL YZER AM FM SIGNAL GENERATOR Call Sam Leonard Tony Stiliman custom work competition needs stock complete hobby line specializing competition accessories discounted prices RADIO SOUTH- AUTHORIZED SERVICE CENTER FOR kruft Pro Line ie r- - bo JR 43 West Nine Mile Rd Pensacola FL 32514 * Futaba Distributor er Inquiries Welcome * correct flag ever correct first place have opportunity confusion Frequency flags accident looking place happen better nothing whole idea Red SRF flag page 128 Rule book cut down number frequency flag errors putting everything need right flag thereby making ridiculously easy mount proper information Due its distinctive size shape color colorblindness eliminated factors consideration Unfortunately cer tain AMA District VP seems unable understand problem Hes proba bly alone spite carryingon about uncertainties colors duplica tions colors numbers flags required difficulty learning understand ing 60 flags etc people prefer con tinuation old inefficient ways learning new better obvious thing Turn ON receiver before turn ON transmitE ng es/Ki sdo n k Continued page 45 Setting needle properly ground first step What really counts in-flight performance becomes somewhat difficult have depend sound also feel properly-tuned engine will slow down sag loops especially consecutive loops ex tended vertical maneuvers first sign sagging loss power retard throttle land open needle extended life service model engine prefer slightly rich nee dle setting can detect slight increase engine speed vertical maneu vers also allows model fly constant speed attitude ter may learn about someone channel interference before fly Dont fly before youve checked thing found 100o should Only birds ever have fly rest us can choose whether situation right flight Safe flight result planning checking testing beforehand get up start getting glitches throttle back land Weve seen far too experts crashed unnecessarily long after received first warning Sometimes glitches come ailerons have fluttered off servo arms have lost screws about jump off servo engines ready fall out rubberbands have failed cold about let wing go bye-bye hinges have pulled out similar disasters have nothing radios interferences Happy Landings George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Engine break-in olden days breaking-in model engine meant hooking up gallon fuel let ting run very rich several hours test stand end time probably nice piston-to-cylinder fit crank bushing well lapped connecting rod worn out Modern manufacturing technology re quires minimal break-in Piston/cylinder fits now controlled machining rather hand fitting lengthy wear-in Similarly cranks sup ported ball bearings now rule rather exception used carburetor-equipped engines rarely use test stand run-in engine anymore normal break-in procedure new engine usually done right airplane select propeller size smaller expect eventually use An example would 9-6 instead 10-6 11-6 instead 11-7 Whether reduction diameter pitch dependent will fly airplane best Open needle valve five six turns start engine about half throttle Let run three four minutes set ting gradually open throttle full point very slowly adjust needle valve progressively leaner ex act point four-cycle two-cycle transi tion back off quarter turn Check adjust idle point least acceptable should pointed out idle quality will improve after few flights final adjustments should made satisfied idle sufficient safely land airplane shut off engine refill fuel tank engine now ready in-flight break-in Dont think might just well get some flying breakingin engine sure beats watching engine run test stand Restart engine recheck both high-speed idle mixture settings doubt about high-speed setting run slightly rich Let takeoff full throttle once airplane safe comfortable altitude pull throttle back one-half three-quarters full full throttle will damage engine smaller prop will fully load should running slightly rich anyway Fly around like minute allowing engine cool itself go back full minute repeat cycle entire flight Repeat flight procedure cou ple flights gradually leaning out mixture until full power achieved After couple full-bore flights can fine-tune idle mixture April 1985 141 Still Using bid Fashioned L4/ing Hinges -rt~s GO gain control efficiency eliminating gap between moveable 2nd stationary control surfaces will amazed performance gained using simple inexpen sive improvement FREE MOVEMENT 450 STRONG AND LIGHTWEIGHT COMPLETELY FUELPROOF COMPATABLE WITH ALL IRON-ON MATERIALS COMES IN 3 PT LENGTHS SMALL 118 ORPRICE 3 ft $250 LARGE 114 Thats Some engines will break-in faster slower pro cedure good rule thumb Three flights cycling part full throttle another two full throttle about hours flying engine broken ready give hours enjoyable flying Now should install propeller proper size experiment various props opti mum performance engines equipped throttle special racing engine applications use test stand test prop smaller diameter carefully cut balanced larger prop preserve hub size strength Refer Table No 4 recommended dimensions test stand should provide very rigid mount engine weighted secured necessary prevent movement Fill fuel tank enough about five minutes running Make sure engine securely mounted install test prop Open needle valve five six turns start engine engine should running very rich high speed After minute gradually lean out mixture small increments until after about five minutes engine close two-cycle operation shut down engine refill fuel tank way have operated engine near in-flight rpmbut quite cool due rich mixture providing excess lubrication succeeding runs want cycle engine between two-cycle fourcycle settings 30-second increments Depending particular engine may take anywhere several EASY TO INSTALL i CUT I/4 DEEP SLIT ALLWG TIE FILL LEAIGrH DY TiE MATAG N/REACtS INSTALL HA//SE USE STRAIGHT PIN 10 AVAIVE SA84LL HOLE EVERY IICH OR SODR/P CYAM2ACRYLATE DUE IAI HOLESCAPLLARY ACF7DN WILL CARRY GLUE 41/kS/N EATI//E /ORIT FOR ADDITIOAI4L SEOAPITI 3 ASERT SS/ALL RIS EVERY FEW INCHES LVT OFF FLUSH FILL AND SAND AS NEEDED FOR FINISHING Send Free info fine products FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 runs engine wrn hold two-cycle setting two minutes noticeable sagging drop off power its ready fly Agaln what youve done run engine slightly above its ground rpm very cool absence normal prop load allows mating surfaces wear proper air rpm speeds Its good idea set engine slightly rich first few flights ensure complete break-in Idle settings Most modem engines equipped carburetor will idle consistently 2500 rpm below An idle speed 3000 rpm below quite satisfactory applications achieve good quality idle rather simple cases However necessary understand adjustments carburetor make sure glow plug good order should pointed out glow plugs have two failure modes com mon broken coil wire opens electrical circuit starting other failure just wear out properly become over-oxidized coil element becomes coated point still maintaining electrical conductivity heat transfer coil combustion mixture impeded point engine opera tion affected condition readily detected engine speed drops upon removal starting battery best rule thumb use new glow plug before trying set idle speeds Once done must also under stand function carburetor adjustments three principle carburetor types air bleed internal mix what call sliding barrel air bleed car buretor simplest addition high-speed main needle valve another yery small screw usually near small drilled hole front body screw turned-in clockwise CW restricts air bleed richening mixture Unscrewing counterclockwise CCW leans-out idle mixture allowing air bleed through drilled hole internal mix carburetor exempli fied very popular Perry idle mixture done internally con trolled large wheel main needle valve side carburetor large wheel has slot aligns mark carb body Either side slot wheel marked tating rds notch CW will richen idle mixture moving towards notch CCW will lean sliding barrel carb has rotating barrel barrel also moves axially needle valve idle mix ture control carbs second needle valve same axis directly opposite main valve needle rotated CW lean out CCW rich much same main needlebut far greater sensitivity adjustment carbs called idle stop screw con trols full-closed position barrel Personally never use Rather use radio throttle trim control closed position full trim full low throt tle set ideal idle pulling trim back way can kill engine Lets adjust idle mixture First make sure install known good new glow plug type recom mended engine first step open carb wide open throttle WOT Adjust highspeed main needle maximum perform ance close throttle far possi ble maintain minimum rpm Should engine die point usually idle mixture too far off have determine dying rich lean Restart engine go slightly higher rpm can maintain Slowly close throttle paying attention sound gurgles burps little prior dying too rich dies slowly usually its too lean Adjust idle mix ture screw according instructions above improve condition slowly methodically either leaning richening mixture improve con dition As condition improves keep reducing idle speed time As approach satisfactory idle speed engine will run longer longer time before dies Now time apply Dave Brown 142 Model Aviation GAPLESS HiNGE SLOTTER - Simplifies installation Gapless Hingas Makes 510114 Sizes Balsa CE $250 technique Dave premier Pattern flier taught following method several years ago After can get engine idle least five seconds before dying retard throttle high speed idle position pinch squeeze off fuel line engine quits sooner before its too lean runs longer its too rich Either way adjust idle mix ture screw needle valve accordingly CCW richen CW lean out adjust main needle Care should taken keep fingers and/or screwdrivers away prop also make minute adjustments never eighth turn time After adjustment keep checking progress make sure youre going right direction ensure havent gone too far satisfied readjust final idle position via throttle trim linkageor using idle stop carbto attain minimum reliable idle speed Thats key course understand what ing go about methodical manner Next month will conclude series discussion glow plugs props fuel care engine RC Aerobatics/Van Putte Continued page 47 tions provided alternative form competition traditional upwind downwind style Unfortunately Howard went say Finally writer Mowrey R VP ought reassured people care what thinks However believe should take time analyze F3A should flown before condemns may time far off RC Aerobatics will flown way Well certainly hope although understand rule proposal fly Turnaround classes competi tion Unfortunately always some people think its necessary junk what have order start something new Turnaround Pattern competition always available anyone wants compete rule bcok states competitors class may compete Turn around Contest Directors force competitors chcose between nor mal class Turnaround because allow ing compete both would either make contest too long cut number rounds flown course fliers normally fly Expert Masters usually win Turnaround tco thats probably what brought about new rules proposal have classes Turnaround Theres another topic reason Jim White called first place claims really arent lot RC Pattern fliers country got information dont know claims about 2500 Pattern fliers competed 1984 Fur ther less 150 contests average contest attendance about 20 Hows grab course theres way confirm claims AMA receives contest reports Contest Directors shouldnt take enormous effort go through reports analyze statistics hes right half members AMA RC fliers about 50000 about 5% RC fliers competed Pattern least once last year Thats small number people expend much time effort money know its strange thing Pattern competitor say think bears lcoking way believe five contests competed last year average 25 conI received letter Mark Corbett Route #2 Box 80-A Waxhaw NC 28173 regarding Pattern proposal called Super Seven letter part said Super Seven one-day Saturday Pattern meet would reduce time involved thus avoiding unnecessary motel fcod fuel costs well problems delayed Sunday fliers As its name reveals Super Seven provides seven-minute flight seven maneuvers everyone takeoff landing would count Expert above would perform touchand-go rest schedule could aligned suite AMA Contest Direc tor holding meet Turnaround-style pattern could use same type format Super Seven could flown Sundayperhaps pro-class event favor Turnaround can afford have spoken re garding idea Mark went say feel change needed believe would instill new life Pattern flying have personally flown models 22 years Pattern eight Masters class six eight cannot attend Pattern meets because time expense time has come really turnaround lcok ultimate goal Any response Super Seven proposal would appreciated Im sure Mark will get lot pro con responses us have drive long distance contests averaged 265 miles five contests last year would probably rather stay two days can afford time can appreciate reasoning one-day contest like describes Let him hear Id like congratulate Steve Rojecki publicly winning Tournament Champions Steve member club April 1985 143 testants
Edition: Model Aviation - 1985/04
Page Numbers: 42, 43, 44, 45, 141, 142, 143
An array Supertigre-manufactured engines having various displacements porting combinations aii tesica inc three propeliers shown picture Table No 3 reports results kit suggests wide variety acceptable engine sIzes say 20 40 usually better use larger size throttle capability amount power can always reduced ntials TUNED PIPES refer exhaust sys tem tuned particular engine operating range ways tune exhaust two-cycle engine have used successfully model engines recollection Bill Wisniew3ki originator modern tuned pipe expansion chamber model engines least made popular circa 1966 Bills system used expansion cham ber amounted inlet pipe diverging nozzle taper inlet pipe connected converging taper very small outlet pipe dimensions systems carefully calculated tested provide maximum power Very basically tuned pipes utilize pressure waves present exhaust supercharge engine increases volumetric efficiency hence produc es power Expansion chambers generate maxi mum performance over narrow operat ing range rpms used specialty events such CL Speed RC boats some RC airplane record categories Currently three other popular 42 Model Aviation Magic Muffleron sport airplane Notethe connectortubing ana ineruci 8flK pressuretap Tuned pipes engine sizes rich lean fuel mixtures break-in pro cedures carbure tors idle settings discussed installment view helping get two-cycle model engine Part 2 John Kilsdonk exhaust tuning systems addition original Wisniewski expansion chamber second system tuned muffler amounts standard expansion chamber additional can over back system has wider operational band quite popular RC applica tions particularly RC Pattern third system called mini-pipe nothing short 3- 6in tuned length constant diameter pipe mini-pipe used some CL events Rat Race Formula 40 D Speed plus RC Formula Quarter Midget Pylon Racing Mini-pipes unlike other systems enhance rather abate exhaust noise suitable using exhaust pressure fuel supply Magic Mufflers fourth typea Typical Pylon Racer installation mini-pipe Quarter Midget Spring around cylinder holds olace mini-aloe Intensifies engine noise rather reducing version mini-pipe addition can reduced-diameter tail pipe noise suppression generate enough back pressure effective fuel system pressure Refer Figure No 3 schematic various tuned pipes should noted concurrent evolution model engine tuned pipes has similar development efforts other two-cycle engine applica tions maximum performance desired noticeably motorcycles go-karts proper application engine timing exhaust tuning given engine tuned exhaust can develop much 50% power although 15% 25% considered realistic dont want get TUNED PIPE ETh TUNED MUFFLER MATIC OF TUNED EXHAUSTS ZD 1 MINI PIPE FIGURE NO 3 DIRECTION OF FLOW MAGIC MUFFLER 0 APPROXIMATE SCALE Inch.L April 1985 43 23 technical necessary should made aware effective exhaust timing length function engine exhaust timing air density exhaust temperature rpm means normally cant just buy tuned exhaust system bolt engine Rather necessary tune system first rule tune system static ground rpm Generally inflight engine speed 500 1500 rpm higher ground rpm properly tuned racing models may several thousand rpm higher way tune system in-flight perform ance select size smaller prop will fly witha 9-6 10-5 instead 10-6 11-6 instead 11-7 etc smaller prop will approximate actual flying rpm engine ground Run engine maximum rpm smaller prop record rpm Next either shorten lengthen exhaust system about /2 re measure rpm engine speed went up youre going right direc tion went down went wrong way no detectable change probably close want Assuming saw increase keep go ing direction about A-in incre ments until quit making progress point should install flying prop fly model check inflight performance Helpful hints include making sure always readjust needle valve length change Actually changing length proper direc tion change will produce richer needle setting last volumetric efficiency increases sec ond hint cut material necessary header pipe attached engine expansion chamber third hint remember exhaust tun ing function air density dramatic temperature altitude changes encountered pipe length will have changed Similar length changes necessary drastic nitro changes fuel exhaust temperature affect wish venture deeply theories expansion chambers several articles particularly Wisniewski model engines published Model Airplane News 1966-67 also series Gordon Jennings motorcycle engine tuning Glenn Lee published update February 1979 Model Aviation EngIne sizes necessarily mean physical appearance weight engine Rather piston displace ment usually designated cubic inches such 15 25 40 60 etc Some engines designated cubic centi meters cc 1cc equals 061 cu Piston displacement determined using different micrometers measure cylinder bore diameter piston stroke sample 46 engine measured bore B 866 piston BDC measured 942 top cylinder top piston Similarly piston rotated TDC measured 163 top cylinder top piston calculated stroke 5 942 minus 163 779 calculate displacement formula 314 x B divided 22 x S sample engine measured displacement 314 x 866 divided 22x 779 cu Table No 3 shows relative perform ance various displacement engines same brands power affected increased displacement type porting used Correct engine size always dilemma modeler especially novice Nor mally compromise between price engine what will fit air plane confusion compounded kit manufacturers list wide range engine sizes particular model kit lists engine sizes 20 40 will probably fly very poorly 20 have choice always pick largest engine size listed particular model Remember cases Left Adjustments Irvine carburetor sliding barrel type used engines Right popular Perry carburetor its adjustments internal mix type idle adjusting different other brands nonetheless easy 44 Model Aviation Tuned muffler installation side-exhaust engine Pattern model Note sili cone tube connector between header pipealso pressure line fuel tank have throttle control speed additional power advantage should need windy day take off heavy grass Rich lean perhaps two troublesome buzzwords refer fuel mixture setting combustion proc esses require proper ratio fuel air applies process whether gas-fired furnace home igniting combustible liquid An open pan gasoline will ignite suf ficient oxygen air Please dont try though take word Internal combustion engines partic ular model engines no exception Normally range fuel-to-air ratios under particular fuel will ig nite Within range no optimum ideal condition known stoichiometric Rich means excess fuel amount available air Lean means excess air amount fuel available richen mixture needle valve turned Out normally counterclockwise allow fuel enter engine Lean leaner just opposite meaning turn needle clockwise restrict amount fuel Mixture setting changes can detected sound frequency change ground tachometer will enhance changes audio-only audio visual However tachometer nec essary cases achieve proper needle setting Before progressing how-to proper needle setting must define couple terms Actually talked about two-cycle four-cycle earlier need amplify buzzwords some As said earlier four-cycle engines have combustion process other revolution two-cycles fire revolution terms also descriptive needle valve settings two-cycle model engines rich needle setting produces slow gurgling sound lower frequency four-cycle sound called four-cycle setting As mixture leaned out frequency creases until crossover point reached sound frequency changes quite abruptly fine-tuned sound tach ometer may show thousand rpm change very slight needle valve movement crossover As needle turned further frequency will increase point sound will flatten out stoichiometric half turn will start slow down starts slow down needle turned over-lean word caution over-lean engine will die very rapid death doubt set richernever operate engine overlean few seconds very helpful technique recheck needle valve setting what call Charmin test think youve got needle set check quickly squeezing fuel supply line quick squeeze should produce audible crease engine speed dont hear increase back needle off open until little practice technique will find squeez ing-the-Charmin excellent cross check needle valve setting Continued page 141 Left 05 4A carb typIfies air bleed type Note small hole Idle mIxture control screw adjust air bleed Right ST Mag IV carb another sliding barrel types Adjusting similar Irvine Mag carbe front runners type carburetor April 1985 45 iunea muTtier installation rear-exnaust Pattern model Note SliP jOintTOriength timing Steve Helms904 478-6745 Al Featuring fast service qualified people latest equipment including SPECTRUM ANAL YZER AM FM SIGNAL GENERATOR Call Sam Leonard Tony Stiliman custom work competition needs stock complete hobby line specializing competition accessories discounted prices RADIO SOUTH- AUTHORIZED SERVICE CENTER FOR kruft Pro Line ie r- - bo JR 43 West Nine Mile Rd Pensacola FL 32514 * Futaba Distributor er Inquiries Welcome * correct flag ever correct first place have opportunity confusion Frequency flags accident looking place happen better nothing whole idea Red SRF flag page 128 Rule book cut down number frequency flag errors putting everything need right flag thereby making ridiculously easy mount proper information Due its distinctive size shape color colorblindness eliminated factors consideration Unfortunately cer tain AMA District VP seems unable understand problem Hes proba bly alone spite carryingon about uncertainties colors duplica tions colors numbers flags required difficulty learning understand ing 60 flags etc people prefer con tinuation old inefficient ways learning new better obvious thing Turn ON receiver before turn ON transmitE ng es/Ki sdo n k Continued page 45 Setting needle properly ground first step What really counts in-flight performance becomes somewhat difficult have depend sound also feel properly-tuned engine will slow down sag loops especially consecutive loops ex tended vertical maneuvers first sign sagging loss power retard throttle land open needle extended life service model engine prefer slightly rich nee dle setting can detect slight increase engine speed vertical maneu vers also allows model fly constant speed attitude ter may learn about someone channel interference before fly Dont fly before youve checked thing found 100o should Only birds ever have fly rest us can choose whether situation right flight Safe flight result planning checking testing beforehand get up start getting glitches throttle back land Weve seen far too experts crashed unnecessarily long after received first warning Sometimes glitches come ailerons have fluttered off servo arms have lost screws about jump off servo engines ready fall out rubberbands have failed cold about let wing go bye-bye hinges have pulled out similar disasters have nothing radios interferences Happy Landings George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Engine break-in olden days breaking-in model engine meant hooking up gallon fuel let ting run very rich several hours test stand end time probably nice piston-to-cylinder fit crank bushing well lapped connecting rod worn out Modern manufacturing technology re quires minimal break-in Piston/cylinder fits now controlled machining rather hand fitting lengthy wear-in Similarly cranks sup ported ball bearings now rule rather exception used carburetor-equipped engines rarely use test stand run-in engine anymore normal break-in procedure new engine usually done right airplane select propeller size smaller expect eventually use An example would 9-6 instead 10-6 11-6 instead 11-7 Whether reduction diameter pitch dependent will fly airplane best Open needle valve five six turns start engine about half throttle Let run three four minutes set ting gradually open throttle full point very slowly adjust needle valve progressively leaner ex act point four-cycle two-cycle transi tion back off quarter turn Check adjust idle point least acceptable should pointed out idle quality will improve after few flights final adjustments should made satisfied idle sufficient safely land airplane shut off engine refill fuel tank engine now ready in-flight break-in Dont think might just well get some flying breakingin engine sure beats watching engine run test stand Restart engine recheck both high-speed idle mixture settings doubt about high-speed setting run slightly rich Let takeoff full throttle once airplane safe comfortable altitude pull throttle back one-half three-quarters full full throttle will damage engine smaller prop will fully load should running slightly rich anyway Fly around like minute allowing engine cool itself go back full minute repeat cycle entire flight Repeat flight procedure cou ple flights gradually leaning out mixture until full power achieved After couple full-bore flights can fine-tune idle mixture April 1985 141 Still Using bid Fashioned L4/ing Hinges -rt~s GO gain control efficiency eliminating gap between moveable 2nd stationary control surfaces will amazed performance gained using simple inexpen sive improvement FREE MOVEMENT 450 STRONG AND LIGHTWEIGHT COMPLETELY FUELPROOF COMPATABLE WITH ALL IRON-ON MATERIALS COMES IN 3 PT LENGTHS SMALL 118 ORPRICE 3 ft $250 LARGE 114 Thats Some engines will break-in faster slower pro cedure good rule thumb Three flights cycling part full throttle another two full throttle about hours flying engine broken ready give hours enjoyable flying Now should install propeller proper size experiment various props opti mum performance engines equipped throttle special racing engine applications use test stand test prop smaller diameter carefully cut balanced larger prop preserve hub size strength Refer Table No 4 recommended dimensions test stand should provide very rigid mount engine weighted secured necessary prevent movement Fill fuel tank enough about five minutes running Make sure engine securely mounted install test prop Open needle valve five six turns start engine engine should running very rich high speed After minute gradually lean out mixture small increments until after about five minutes engine close two-cycle operation shut down engine refill fuel tank way have operated engine near in-flight rpmbut quite cool due rich mixture providing excess lubrication succeeding runs want cycle engine between two-cycle fourcycle settings 30-second increments Depending particular engine may take anywhere several EASY TO INSTALL i CUT I/4 DEEP SLIT ALLWG TIE FILL LEAIGrH DY TiE MATAG N/REACtS INSTALL HA//SE USE STRAIGHT PIN 10 AVAIVE SA84LL HOLE EVERY IICH OR SODR/P CYAM2ACRYLATE DUE IAI HOLESCAPLLARY ACF7DN WILL CARRY GLUE 41/kS/N EATI//E /ORIT FOR ADDITIOAI4L SEOAPITI 3 ASERT SS/ALL RIS EVERY FEW INCHES LVT OFF FLUSH FILL AND SAND AS NEEDED FOR FINISHING Send Free info fine products FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 runs engine wrn hold two-cycle setting two minutes noticeable sagging drop off power its ready fly Agaln what youve done run engine slightly above its ground rpm very cool absence normal prop load allows mating surfaces wear proper air rpm speeds Its good idea set engine slightly rich first few flights ensure complete break-in Idle settings Most modem engines equipped carburetor will idle consistently 2500 rpm below An idle speed 3000 rpm below quite satisfactory applications achieve good quality idle rather simple cases However necessary understand adjustments carburetor make sure glow plug good order should pointed out glow plugs have two failure modes com mon broken coil wire opens electrical circuit starting other failure just wear out properly become over-oxidized coil element becomes coated point still maintaining electrical conductivity heat transfer coil combustion mixture impeded point engine opera tion affected condition readily detected engine speed drops upon removal starting battery best rule thumb use new glow plug before trying set idle speeds Once done must also under stand function carburetor adjustments three principle carburetor types air bleed internal mix what call sliding barrel air bleed car buretor simplest addition high-speed main needle valve another yery small screw usually near small drilled hole front body screw turned-in clockwise CW restricts air bleed richening mixture Unscrewing counterclockwise CCW leans-out idle mixture allowing air bleed through drilled hole internal mix carburetor exempli fied very popular Perry idle mixture done internally con trolled large wheel main needle valve side carburetor large wheel has slot aligns mark carb body Either side slot wheel marked tating rds notch CW will richen idle mixture moving towards notch CCW will lean sliding barrel carb has rotating barrel barrel also moves axially needle valve idle mix ture control carbs second needle valve same axis directly opposite main valve needle rotated CW lean out CCW rich much same main needlebut far greater sensitivity adjustment carbs called idle stop screw con trols full-closed position barrel Personally never use Rather use radio throttle trim control closed position full trim full low throt tle set ideal idle pulling trim back way can kill engine Lets adjust idle mixture First make sure install known good new glow plug type recom mended engine first step open carb wide open throttle WOT Adjust highspeed main needle maximum perform ance close throttle far possi ble maintain minimum rpm Should engine die point usually idle mixture too far off have determine dying rich lean Restart engine go slightly higher rpm can maintain Slowly close throttle paying attention sound gurgles burps little prior dying too rich dies slowly usually its too lean Adjust idle mix ture screw according instructions above improve condition slowly methodically either leaning richening mixture improve con dition As condition improves keep reducing idle speed time As approach satisfactory idle speed engine will run longer longer time before dies Now time apply Dave Brown 142 Model Aviation GAPLESS HiNGE SLOTTER - Simplifies installation Gapless Hingas Makes 510114 Sizes Balsa CE $250 technique Dave premier Pattern flier taught following method several years ago After can get engine idle least five seconds before dying retard throttle high speed idle position pinch squeeze off fuel line engine quits sooner before its too lean runs longer its too rich Either way adjust idle mix ture screw needle valve accordingly CCW richen CW lean out adjust main needle Care should taken keep fingers and/or screwdrivers away prop also make minute adjustments never eighth turn time After adjustment keep checking progress make sure youre going right direction ensure havent gone too far satisfied readjust final idle position via throttle trim linkageor using idle stop carbto attain minimum reliable idle speed Thats key course understand what ing go about methodical manner Next month will conclude series discussion glow plugs props fuel care engine RC Aerobatics/Van Putte Continued page 47 tions provided alternative form competition traditional upwind downwind style Unfortunately Howard went say Finally writer Mowrey R VP ought reassured people care what thinks However believe should take time analyze F3A should flown before condemns may time far off RC Aerobatics will flown way Well certainly hope although understand rule proposal fly Turnaround classes competi tion Unfortunately always some people think its necessary junk what have order start something new Turnaround Pattern competition always available anyone wants compete rule bcok states competitors class may compete Turn around Contest Directors force competitors chcose between nor mal class Turnaround because allow ing compete both would either make contest too long cut number rounds flown course fliers normally fly Expert Masters usually win Turnaround tco thats probably what brought about new rules proposal have classes Turnaround Theres another topic reason Jim White called first place claims really arent lot RC Pattern fliers country got information dont know claims about 2500 Pattern fliers competed 1984 Fur ther less 150 contests average contest attendance about 20 Hows grab course theres way confirm claims AMA receives contest reports Contest Directors shouldnt take enormous effort go through reports analyze statistics hes right half members AMA RC fliers about 50000 about 5% RC fliers competed Pattern least once last year Thats small number people expend much time effort money know its strange thing Pattern competitor say think bears lcoking way believe five contests competed last year average 25 conI received letter Mark Corbett Route #2 Box 80-A Waxhaw NC 28173 regarding Pattern proposal called Super Seven letter part said Super Seven one-day Saturday Pattern meet would reduce time involved thus avoiding unnecessary motel fcod fuel costs well problems delayed Sunday fliers As its name reveals Super Seven provides seven-minute flight seven maneuvers everyone takeoff landing would count Expert above would perform touchand-go rest schedule could aligned suite AMA Contest Direc tor holding meet Turnaround-style pattern could use same type format Super Seven could flown Sundayperhaps pro-class event favor Turnaround can afford have spoken re garding idea Mark went say feel change needed believe would instill new life Pattern flying have personally flown models 22 years Pattern eight Masters class six eight cannot attend Pattern meets because time expense time has come really turnaround lcok ultimate goal Any response Super Seven proposal would appreciated Im sure Mark will get lot pro con responses us have drive long distance contests averaged 265 miles five contests last year would probably rather stay two days can afford time can appreciate reasoning one-day contest like describes Let him hear Id like congratulate Steve Rojecki publicly winning Tournament Champions Steve member club April 1985 143 testants
Edition: Model Aviation - 1985/04
Page Numbers: 42, 43, 44, 45, 141, 142, 143
An array Supertigre-manufactured engines having various displacements porting combinations aii tesica inc three propeliers shown picture Table No 3 reports results kit suggests wide variety acceptable engine sIzes say 20 40 usually better use larger size throttle capability amount power can always reduced ntials TUNED PIPES refer exhaust sys tem tuned particular engine operating range ways tune exhaust two-cycle engine have used successfully model engines recollection Bill Wisniew3ki originator modern tuned pipe expansion chamber model engines least made popular circa 1966 Bills system used expansion cham ber amounted inlet pipe diverging nozzle taper inlet pipe connected converging taper very small outlet pipe dimensions systems carefully calculated tested provide maximum power Very basically tuned pipes utilize pressure waves present exhaust supercharge engine increases volumetric efficiency hence produc es power Expansion chambers generate maxi mum performance over narrow operat ing range rpms used specialty events such CL Speed RC boats some RC airplane record categories Currently three other popular 42 Model Aviation Magic Muffleron sport airplane Notethe connectortubing ana ineruci 8flK pressuretap Tuned pipes engine sizes rich lean fuel mixtures break-in pro cedures carbure tors idle settings discussed installment view helping get two-cycle model engine Part 2 John Kilsdonk exhaust tuning systems addition original Wisniewski expansion chamber second system tuned muffler amounts standard expansion chamber additional can over back system has wider operational band quite popular RC applica tions particularly RC Pattern third system called mini-pipe nothing short 3- 6in tuned length constant diameter pipe mini-pipe used some CL events Rat Race Formula 40 D Speed plus RC Formula Quarter Midget Pylon Racing Mini-pipes unlike other systems enhance rather abate exhaust noise suitable using exhaust pressure fuel supply Magic Mufflers fourth typea Typical Pylon Racer installation mini-pipe Quarter Midget Spring around cylinder holds olace mini-aloe Intensifies engine noise rather reducing version mini-pipe addition can reduced-diameter tail pipe noise suppression generate enough back pressure effective fuel system pressure Refer Figure No 3 schematic various tuned pipes should noted concurrent evolution model engine tuned pipes has similar development efforts other two-cycle engine applica tions maximum performance desired noticeably motorcycles go-karts proper application engine timing exhaust tuning given engine tuned exhaust can develop much 50% power although 15% 25% considered realistic dont want get TUNED PIPE ETh TUNED MUFFLER MATIC OF TUNED EXHAUSTS ZD 1 MINI PIPE FIGURE NO 3 DIRECTION OF FLOW MAGIC MUFFLER 0 APPROXIMATE SCALE Inch.L April 1985 43 23 technical necessary should made aware effective exhaust timing length function engine exhaust timing air density exhaust temperature rpm means normally cant just buy tuned exhaust system bolt engine Rather necessary tune system first rule tune system static ground rpm Generally inflight engine speed 500 1500 rpm higher ground rpm properly tuned racing models may several thousand rpm higher way tune system in-flight perform ance select size smaller prop will fly witha 9-6 10-5 instead 10-6 11-6 instead 11-7 etc smaller prop will approximate actual flying rpm engine ground Run engine maximum rpm smaller prop record rpm Next either shorten lengthen exhaust system about /2 re measure rpm engine speed went up youre going right direc tion went down went wrong way no detectable change probably close want Assuming saw increase keep go ing direction about A-in incre ments until quit making progress point should install flying prop fly model check inflight performance Helpful hints include making sure always readjust needle valve length change Actually changing length proper direc tion change will produce richer needle setting last volumetric efficiency increases sec ond hint cut material necessary header pipe attached engine expansion chamber third hint remember exhaust tun ing function air density dramatic temperature altitude changes encountered pipe length will have changed Similar length changes necessary drastic nitro changes fuel exhaust temperature affect wish venture deeply theories expansion chambers several articles particularly Wisniewski model engines published Model Airplane News 1966-67 also series Gordon Jennings motorcycle engine tuning Glenn Lee published update February 1979 Model Aviation EngIne sizes necessarily mean physical appearance weight engine Rather piston displace ment usually designated cubic inches such 15 25 40 60 etc Some engines designated cubic centi meters cc 1cc equals 061 cu Piston displacement determined using different micrometers measure cylinder bore diameter piston stroke sample 46 engine measured bore B 866 piston BDC measured 942 top cylinder top piston Similarly piston rotated TDC measured 163 top cylinder top piston calculated stroke 5 942 minus 163 779 calculate displacement formula 314 x B divided 22 x S sample engine measured displacement 314 x 866 divided 22x 779 cu Table No 3 shows relative perform ance various displacement engines same brands power affected increased displacement type porting used Correct engine size always dilemma modeler especially novice Nor mally compromise between price engine what will fit air plane confusion compounded kit manufacturers list wide range engine sizes particular model kit lists engine sizes 20 40 will probably fly very poorly 20 have choice always pick largest engine size listed particular model Remember cases Left Adjustments Irvine carburetor sliding barrel type used engines Right popular Perry carburetor its adjustments internal mix type idle adjusting different other brands nonetheless easy 44 Model Aviation Tuned muffler installation side-exhaust engine Pattern model Note sili cone tube connector between header pipealso pressure line fuel tank have throttle control speed additional power advantage should need windy day take off heavy grass Rich lean perhaps two troublesome buzzwords refer fuel mixture setting combustion proc esses require proper ratio fuel air applies process whether gas-fired furnace home igniting combustible liquid An open pan gasoline will ignite suf ficient oxygen air Please dont try though take word Internal combustion engines partic ular model engines no exception Normally range fuel-to-air ratios under particular fuel will ig nite Within range no optimum ideal condition known stoichiometric Rich means excess fuel amount available air Lean means excess air amount fuel available richen mixture needle valve turned Out normally counterclockwise allow fuel enter engine Lean leaner just opposite meaning turn needle clockwise restrict amount fuel Mixture setting changes can detected sound frequency change ground tachometer will enhance changes audio-only audio visual However tachometer nec essary cases achieve proper needle setting Before progressing how-to proper needle setting must define couple terms Actually talked about two-cycle four-cycle earlier need amplify buzzwords some As said earlier four-cycle engines have combustion process other revolution two-cycles fire revolution terms also descriptive needle valve settings two-cycle model engines rich needle setting produces slow gurgling sound lower frequency four-cycle sound called four-cycle setting As mixture leaned out frequency creases until crossover point reached sound frequency changes quite abruptly fine-tuned sound tach ometer may show thousand rpm change very slight needle valve movement crossover As needle turned further frequency will increase point sound will flatten out stoichiometric half turn will start slow down starts slow down needle turned over-lean word caution over-lean engine will die very rapid death doubt set richernever operate engine overlean few seconds very helpful technique recheck needle valve setting what call Charmin test think youve got needle set check quickly squeezing fuel supply line quick squeeze should produce audible crease engine speed dont hear increase back needle off open until little practice technique will find squeez ing-the-Charmin excellent cross check needle valve setting Continued page 141 Left 05 4A carb typIfies air bleed type Note small hole Idle mIxture control screw adjust air bleed Right ST Mag IV carb another sliding barrel types Adjusting similar Irvine Mag carbe front runners type carburetor April 1985 45 iunea muTtier installation rear-exnaust Pattern model Note SliP jOintTOriength timing Steve Helms904 478-6745 Al Featuring fast service qualified people latest equipment including SPECTRUM ANAL YZER AM FM SIGNAL GENERATOR Call Sam Leonard Tony Stiliman custom work competition needs stock complete hobby line specializing competition accessories discounted prices RADIO SOUTH- AUTHORIZED SERVICE CENTER FOR kruft Pro Line ie r- - bo JR 43 West Nine Mile Rd Pensacola FL 32514 * Futaba Distributor er Inquiries Welcome * correct flag ever correct first place have opportunity confusion Frequency flags accident looking place happen better nothing whole idea Red SRF flag page 128 Rule book cut down number frequency flag errors putting everything need right flag thereby making ridiculously easy mount proper information Due its distinctive size shape color colorblindness eliminated factors consideration Unfortunately cer tain AMA District VP seems unable understand problem Hes proba bly alone spite carryingon about uncertainties colors duplica tions colors numbers flags required difficulty learning understand ing 60 flags etc people prefer con tinuation old inefficient ways learning new better obvious thing Turn ON receiver before turn ON transmitE ng es/Ki sdo n k Continued page 45 Setting needle properly ground first step What really counts in-flight performance becomes somewhat difficult have depend sound also feel properly-tuned engine will slow down sag loops especially consecutive loops ex tended vertical maneuvers first sign sagging loss power retard throttle land open needle extended life service model engine prefer slightly rich nee dle setting can detect slight increase engine speed vertical maneu vers also allows model fly constant speed attitude ter may learn about someone channel interference before fly Dont fly before youve checked thing found 100o should Only birds ever have fly rest us can choose whether situation right flight Safe flight result planning checking testing beforehand get up start getting glitches throttle back land Weve seen far too experts crashed unnecessarily long after received first warning Sometimes glitches come ailerons have fluttered off servo arms have lost screws about jump off servo engines ready fall out rubberbands have failed cold about let wing go bye-bye hinges have pulled out similar disasters have nothing radios interferences Happy Landings George M Myers 70 Froehlich Farm Rd Hicksville NY 11801 Engine break-in olden days breaking-in model engine meant hooking up gallon fuel let ting run very rich several hours test stand end time probably nice piston-to-cylinder fit crank bushing well lapped connecting rod worn out Modern manufacturing technology re quires minimal break-in Piston/cylinder fits now controlled machining rather hand fitting lengthy wear-in Similarly cranks sup ported ball bearings now rule rather exception used carburetor-equipped engines rarely use test stand run-in engine anymore normal break-in procedure new engine usually done right airplane select propeller size smaller expect eventually use An example would 9-6 instead 10-6 11-6 instead 11-7 Whether reduction diameter pitch dependent will fly airplane best Open needle valve five six turns start engine about half throttle Let run three four minutes set ting gradually open throttle full point very slowly adjust needle valve progressively leaner ex act point four-cycle two-cycle transi tion back off quarter turn Check adjust idle point least acceptable should pointed out idle quality will improve after few flights final adjustments should made satisfied idle sufficient safely land airplane shut off engine refill fuel tank engine now ready in-flight break-in Dont think might just well get some flying breakingin engine sure beats watching engine run test stand Restart engine recheck both high-speed idle mixture settings doubt about high-speed setting run slightly rich Let takeoff full throttle once airplane safe comfortable altitude pull throttle back one-half three-quarters full full throttle will damage engine smaller prop will fully load should running slightly rich anyway Fly around like minute allowing engine cool itself go back full minute repeat cycle entire flight Repeat flight procedure cou ple flights gradually leaning out mixture until full power achieved After couple full-bore flights can fine-tune idle mixture April 1985 141 Still Using bid Fashioned L4/ing Hinges -rt~s GO gain control efficiency eliminating gap between moveable 2nd stationary control surfaces will amazed performance gained using simple inexpen sive improvement FREE MOVEMENT 450 STRONG AND LIGHTWEIGHT COMPLETELY FUELPROOF COMPATABLE WITH ALL IRON-ON MATERIALS COMES IN 3 PT LENGTHS SMALL 118 ORPRICE 3 ft $250 LARGE 114 Thats Some engines will break-in faster slower pro cedure good rule thumb Three flights cycling part full throttle another two full throttle about hours flying engine broken ready give hours enjoyable flying Now should install propeller proper size experiment various props opti mum performance engines equipped throttle special racing engine applications use test stand test prop smaller diameter carefully cut balanced larger prop preserve hub size strength Refer Table No 4 recommended dimensions test stand should provide very rigid mount engine weighted secured necessary prevent movement Fill fuel tank enough about five minutes running Make sure engine securely mounted install test prop Open needle valve five six turns start engine engine should running very rich high speed After minute gradually lean out mixture small increments until after about five minutes engine close two-cycle operation shut down engine refill fuel tank way have operated engine near in-flight rpmbut quite cool due rich mixture providing excess lubrication succeeding runs want cycle engine between two-cycle fourcycle settings 30-second increments Depending particular engine may take anywhere several EASY TO INSTALL i CUT I/4 DEEP SLIT ALLWG TIE FILL LEAIGrH DY TiE MATAG N/REACtS INSTALL HA//SE USE STRAIGHT PIN 10 AVAIVE SA84LL HOLE EVERY IICH OR SODR/P CYAM2ACRYLATE DUE IAI HOLESCAPLLARY ACF7DN WILL CARRY GLUE 41/kS/N EATI//E /ORIT FOR ADDITIOAI4L SEOAPITI 3 ASERT SS/ALL RIS EVERY FEW INCHES LVT OFF FLUSH FILL AND SAND AS NEEDED FOR FINISHING Send Free info fine products FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 runs engine wrn hold two-cycle setting two minutes noticeable sagging drop off power its ready fly Agaln what youve done run engine slightly above its ground rpm very cool absence normal prop load allows mating surfaces wear proper air rpm speeds Its good idea set engine slightly rich first few flights ensure complete break-in Idle settings Most modem engines equipped carburetor will idle consistently 2500 rpm below An idle speed 3000 rpm below quite satisfactory applications achieve good quality idle rather simple cases However necessary understand adjustments carburetor make sure glow plug good order should pointed out glow plugs have two failure modes com mon broken coil wire opens electrical circuit starting other failure just wear out properly become over-oxidized coil element becomes coated point still maintaining electrical conductivity heat transfer coil combustion mixture impeded point engine opera tion affected condition readily detected engine speed drops upon removal starting battery best rule thumb use new glow plug before trying set idle speeds Once done must also under stand function carburetor adjustments three principle carburetor types air bleed internal mix what call sliding barrel air bleed car buretor simplest addition high-speed main needle valve another yery small screw usually near small drilled hole front body screw turned-in clockwise CW restricts air bleed richening mixture Unscrewing counterclockwise CCW leans-out idle mixture allowing air bleed through drilled hole internal mix carburetor exempli fied very popular Perry idle mixture done internally con trolled large wheel main needle valve side carburetor large wheel has slot aligns mark carb body Either side slot wheel marked tating rds notch CW will richen idle mixture moving towards notch CCW will lean sliding barrel carb has rotating barrel barrel also moves axially needle valve idle mix ture control carbs second needle valve same axis directly opposite main valve needle rotated CW lean out CCW rich much same main needlebut far greater sensitivity adjustment carbs called idle stop screw con trols full-closed position barrel Personally never use Rather use radio throttle trim control closed position full trim full low throt tle set ideal idle pulling trim back way can kill engine Lets adjust idle mixture First make sure install known good new glow plug type recom mended engine first step open carb wide open throttle WOT Adjust highspeed main needle maximum perform ance close throttle far possi ble maintain minimum rpm Should engine die point usually idle mixture too far off have determine dying rich lean Restart engine go slightly higher rpm can maintain Slowly close throttle paying attention sound gurgles burps little prior dying too rich dies slowly usually its too lean Adjust idle mix ture screw according instructions above improve condition slowly methodically either leaning richening mixture improve con dition As condition improves keep reducing idle speed time As approach satisfactory idle speed engine will run longer longer time before dies Now time apply Dave Brown 142 Model Aviation GAPLESS HiNGE SLOTTER - Simplifies installation Gapless Hingas Makes 510114 Sizes Balsa CE $250 technique Dave premier Pattern flier taught following method several years ago After can get engine idle least five seconds before dying retard throttle high speed idle position pinch squeeze off fuel line engine quits sooner before its too lean runs longer its too rich Either way adjust idle mix ture screw needle valve accordingly CCW richen CW lean out adjust main needle Care should taken keep fingers and/or screwdrivers away prop also make minute adjustments never eighth turn time After adjustment keep checking progress make sure youre going right direction ensure havent gone too far satisfied readjust final idle position via throttle trim linkageor using idle stop carbto attain minimum reliable idle speed Thats key course understand what ing go about methodical manner Next month will conclude series discussion glow plugs props fuel care engine RC Aerobatics/Van Putte Continued page 47 tions provided alternative form competition traditional upwind downwind style Unfortunately Howard went say Finally writer Mowrey R VP ought reassured people care what thinks However believe should take time analyze F3A should flown before condemns may time far off RC Aerobatics will flown way Well certainly hope although understand rule proposal fly Turnaround classes competi tion Unfortunately always some people think its necessary junk what have order start something new Turnaround Pattern competition always available anyone wants compete rule bcok states competitors class may compete Turn around Contest Directors force competitors chcose between nor mal class Turnaround because allow ing compete both would either make contest too long cut number rounds flown course fliers normally fly Expert Masters usually win Turnaround tco thats probably what brought about new rules proposal have classes Turnaround Theres another topic reason Jim White called first place claims really arent lot RC Pattern fliers country got information dont know claims about 2500 Pattern fliers competed 1984 Fur ther less 150 contests average contest attendance about 20 Hows grab course theres way confirm claims AMA receives contest reports Contest Directors shouldnt take enormous effort go through reports analyze statistics hes right half members AMA RC fliers about 50000 about 5% RC fliers competed Pattern least once last year Thats small number people expend much time effort money know its strange thing Pattern competitor say think bears lcoking way believe five contests competed last year average 25 conI received letter Mark Corbett Route #2 Box 80-A Waxhaw NC 28173 regarding Pattern proposal called Super Seven letter part said Super Seven one-day Saturday Pattern meet would reduce time involved thus avoiding unnecessary motel fcod fuel costs well problems delayed Sunday fliers As its name reveals Super Seven provides seven-minute flight seven maneuvers everyone takeoff landing would count Expert above would perform touchand-go rest schedule could aligned suite AMA Contest Direc tor holding meet Turnaround-style pattern could use same type format Super Seven could flown Sundayperhaps pro-class event favor Turnaround can afford have spoken re garding idea Mark went say feel change needed believe would instill new life Pattern flying have personally flown models 22 years Pattern eight Masters class six eight cannot attend Pattern meets because time expense time has come really turnaround lcok ultimate goal Any response Super Seven proposal would appreciated Im sure Mark will get lot pro con responses us have drive long distance contests averaged 265 miles five contests last year would probably rather stay two days can afford time can appreciate reasoning one-day contest like describes Let him hear Id like congratulate Steve Rojecki publicly winning Tournament Champions Steve member club April 1985 143 testants