U Joe Wagner ANYTIME someone makes snide remark about toy airplanes might squelch fact model aircraft highest-powered propeller-driven vehicles existence thats narrow margin either Take speediest fastest-climbing prop-equipped fighter ever built Grummans F8F Bearcat weighed 9334 pounds 2800 horsepower Thats 31/3 pounds per horsepower Navy fighter version recent world-record-setting speciallymodified Rare Bear Bearcat came out somewhere around two pounds per horsepower Thats mighty impressive weight-to-power ratiountil consider todays competition Free Flight models nearly double typical 15-powered FlC FF entry weighs 27 ounces its engine develops about 11/2 horsepower works out fantastic 110 lb/hp reason incredible power levels todays Free Flight airplanes FF has effectively become racing eventthe race~ maximum vertical distance given time Competing requires much same sort power plants Control Line Speed extraordinary power output todays competition model airplane engines comes intensive design development very latest metallurgical advances high-nitro fuel rpm close-to-30OOO range earlier column mentioned Rule Thumb approximate maximum speed limit mph propdriven airplane equals propeller pitch inches times engine rpm thousands Thus CL Stunt model pulled 9 x 5 prop spinning 10000 rpm just cant travel about 50mph November 1997 83 MP Jet 061 Carison Engine Imports can used sport Control Line models competition Free Flight 1932 Brown 60 powered FF models up 10-foot wingspan yet developed less horspower some modern competition 05s RC FF versions Cox/K&B Conquest may have Americas highest-performing production-made 15 Foxs ball-bearing 25 puts out power runs reliably its famous shorter-intake ancestor Fox 35 want speed two ways get higher-pitch prop greater rpmand preferably both Notice horsepower engine develops doesnt enter directly relationship could have fourhorsepower chain saw engine model driving eight-inch-pitch prop regardless its diameter 9000 rpm aircraft couldnt exceed about 72 mph full-throttle dive Thats reason todays 30000 rpm model engines performance astounds 180 hp Rossi 21 26 hp MP Jet 061 course horsepower figures come dynamometer testing dont necessarily represent what happens flight example take Brown Junior 60 powered Joe Konefes Buzzard Bombshell its 49-minute flight won Class C Free Flight 1941 Nationals Brown put out well under 1/5 horsepower day Any new Russian competition /IA glow engines can outdo Yet installed say AME nose Joes famous prewar record-setter 30K rpm could barely manage taxi six-foot 31/2 pound thick-winged craft High rpms everything 84 Model Aviation uri extension Wagner-modified PAW 06 diesel eliminates Extended air intakes catching Heres Estes latest inlet stall problems sometimes encountered original version well-known Cox reed-valve product engine TRU-TURN now offers very finest versatile light weight PROP HUBS turned solid barstock inside out true running hub new hub will mount motor standard TRU-TURN adapter kit big bird multi-bolt applications TRU-TURN has covered n U S TRU-TURN also has PROP NUT will fit motor precision PROP NUTS come engine thread sizes two different shapes available stock Ask hobby dealer name z PRECISION MODEL PRODUCTS Romco Manufactu ng ncEli QUALITY VERSATILITY GREAT LOOKS SAFETY PO Box 836 South Houston Texas 77587 713 / 943 1867 need racing events ducted fans just about other kind model flying 15000 rpm plenty fast enough Thats what MP Jet 061 delivers 5% nitro fuel APC 7 x 3 prop providing close-to-ideal power small CL Stunt models High rpm has dangers too Propeller hub stresses increase square rpm centrifugal force alone fourth power Thats because additional thrust torque loads prop hub also go up square rpm increase model engine speed doubles eg 10K 20K rpm forces tending pull its prop apart increase sixteen times True modem propeller makers have beefed up products APC props have featured massive hubs right start Windsor Master Airscrew folks strengthened some months ago Fliers compete models using engines turn 30K rpm range would think trying props skimpy hubs guys pros know better Still theres always guy just loves hear engine shriek may tempted put plain nylon 7 x 4 honkin Conquest 15 see just fast itll spin Thats tragedy making Back Good Old Days sizable number us gas model fliers put fair amount time ingenuity hopping up engines Most effort did little good some did harm Still felt accomplishing something worthwhile really amounted personalizing power plants Theres always temptation mechanically minded people customize things like automobiles bikes computers boats model airplane engines todays everincreasing level technology its getting harder harder find ways improve itemsespecially ways within technical financial means However relatively simple highly beneficial modification can make model airplane engines boosts reliability usually adds power makes engine look noticeably different stock Extend venturi isnt new idea merely little-understood First investigated reported prewar British model engine expert Col C E Bowden lengthened air intakes never caught An enthusiastic article E C Ted Martin MAN 30 years ago also failed popularize improvement Now its turn try about 40 years Ive reworking customizing model engines time single beneficial change Ive ever found has adding venturi extensions Superior Balsa & Hobby SupplyGN & ORDER HOURS it Home Paget http//pw2/-balsalsupenorhtm ECTION 700 AM 700 020-G Centralia Street Hawaiian Gardens CA 9071650% SURCHARGE PST CA TIME FGRS & DEALERS Monday SaturdayPlease add sufficient amount excess refunded shipping UPS Parcel Post PLUS $285 handlingEND FOR RESELLER 800 488-9525 500 Mm order accept Visa Mastercard Checks CA sales add 825% sales tax GRAM Info 582865-3220 FAX 562860-0327 http//pw2lnetcomcom/balsalSuperiOrhtnlPilces sitect chn 3/97 E complete price list Shop hours 800AM 300PM Mon Fri BALSAspucrnss STICKSBALSA SHEETS TRAILING EDGES 36 LEADING EDGESAircraft Grade Birch yood 11160 129311603143547,.6x1212x12129241294848x48 DOUBLEBALSAPRICES164CM36481/8 o112Ii140 279 610 950 3600 STICKS3648 1/1664CM364811464CM36483132013142114 xl39 64 1/19o1/16101/4o 11422301/8 015/16x1-1/448 71 1/16x313210114031827333/16o1~318 01-1/256 853pjy 1/1601/810141/4x1/229411/4 xl92781/2 x2go 1/4x318 503/803/8751132 3/8 xl6786314 x3160 1/2 851/2x1/21053Ply95180335 6352475 1116x3116II151/4x5/837501/2 xl76104 1/20314145314x3/41601/16 1/16x1/41215l/4x3/44258264CM3641 31401170lxi1883My95180335 6252400 1/16o3151316 1/1601/217215/1664CM3648irzxxiu 36AILERONSMSLdgEd9eRetl6CtveT8p6 35U 1/16 x238 50 1/16x3/422295/16o9/1627353/22x246 611/4 xl57 3/3284CM36485/16o1/238483116x260741/4 xl-1/274WIDEBALSASHEETS1/8 3/32x 3/3211125/16x3144682114 x268601/4 x260145260550 9503800 3/320 1/812 14318 x2861199/16x1-1/476o36 8e38 j45 35fl.JJL 5/16031831 29118 x248851/4 xl-I/4 A60 135263 504 9753800 3/32x311613165/864CM36481/2 x21101435/l6x11/2751/161412282003183/16 3/3201/414183/8x31836455/iBo 28631321602472253454 Ply 99 185347 6892600 3/3203/815183/8x1/24057364CM3648318 01-1/2831/81792782503802/32x1/21824318x8/847581/32x34360318x2953116 206314285440125230 3807252850 3/32x3/42632318x31453681/160344603/8o2-1/21061/4 2353803255305PI 3/32 x 352671/2x1-1/295318 300477420665 3/8 1/864CM36481/8 x363841/2x21061/2 5105857158507py150285 55010003900 1/8x1/811131/201/249643/iBoS76103 1/8x311613181/2xS/857761/4 x394130 TRI 1/8x1/414211/2x31460825/160310915236ANGLESBALSABLOCKS200350 58011254300 1/8x3181523318 x31151701/401/429lxi 243030!t. 1/8x1/221275/564CM 36 x3 150 206 f%,068075060iiW 1/8 1/000428 365/8o5/860 86JCM3180318102 989 165 160215elosRy 751252354501700 1/201/240 5/Sol93 1141/22x46692314x3/4IN13120235285329i/8ute 3/1664CM56481/16x468lxi68I 04 157 325 376 425PoflIer751252354501700 311603/181423 Other Fine Products 3133482 1142x2 175 2A5 282330 3116x1/418 27 NHP West 4 160 423 1/4Lile Systems36 DOWELS2o4265460530715p 901753456502470 3/16X3182128& Bob Smith Epoxy3/1654109199 3/1601/22436 Tools Supplies1/4 041521791/8165/1627303330995750865 3116X3143045318 x4210285311617 3/8373x44607708201235OBECHI- 1/32x 14x lOS -$1475 Composits Hordware 1/2 04285 3361/4301/2 54 404 690 880 1290 1800 CAS Bob Smith Flash 36 Bargain Balsa Bundles $295 AM SHEETS 81u2x12x24 368 mc1/2oz210185Wlste2xl2x24 175 8ue2x24x48 1328 Gapor1 oz3493001/32x3 8 1/22x461/8x1/8383116x3116301/4x1/4 19318o3/812 1/201/2 8 Thick2oz5955001/16x3 8 1/16x461/8x3116323116x1/4231/4x318 15318x1/210 1/2x314 6 W14e2x24x48 630 EPP2x12x24 Thk8oz179516503/32x3 8 3/320451/8x1/4303116x31820l/4x1/2 143180314 81 0Al51O l6oz30001/8 03 6 1/8 x4 41/80318 128 3/1601/2 17 1/40314 10W14te4x12o24 350 EPP2x18O48 1 iii 2ozlhiop88og-1 seexweS50 31160315311604 31/801/2 20 31160314 13Limited availabilityCalI OdSIese 1/2oz4553651/4 03 4 1/4 0431/80314 15Denotesquaatityperbuadle/M4le4x24x48 1275 EPP2036x48 3000 1 oz845665 3/8 033318 042* Some stajas womiholes & mogiilaroIncoflel Foam CtJtSflg VVlre -8 feel $300 Tho$600 HartEg Oversize SNp9 C119e Thok2 OZ14951200 1/2 x3 2 1/204 2 Doing improves fuel draw combined smoothly contoured belimouth air inlet boosts running reliability adds power too Heres inlet port model engine two stroke four-stroke open just part shaft revolution Thats time air/fuel mixture can enter reason flow through entry port pulsates Pulsating airflow model engines intake detrimental because takes time flow get started up speed just incoming air/fuel flow gets moving along nicely engine its inlet closes cuts inflow off air/fuel mix approaching inlet port instant bounces back Its moving wrong way inlet port reopens has reverse again takes time Airflow oscillates inlet port costs power limits amount oxygen engine can inhale bum its fuel As fuel supply suction could hardly ask worse conditions delivering consistent reliable fuel flow pulsating vacuum spraybar orifice reason suction-feed model engine can overcome problem airstream passing through its venturi has both momentum compressibility inertia air accelerating inward through entry venturi tends keep going though flow other end stopand-go does compressing air ahead passageway passageway short amount air within given instant may have enough moving mass overcome pulsation engines inlet port Speeding up flow increases momentum however Thats source saying Model engines happier high rpm passageway long its different story Theres enough air mass moving within keep inflow steady low rpm reason todays RC engines idle much reliably yesteryear total inlet passage length greater theres venturi customizing story Theres also mysterious inlet stall phenomenon Probably first notice ill effects inlet stall ducted-fan fliers branch aeromodeling new experimenters found contour ducts entry much effect airflow through its cross-sectional area Sharpedged duct entries stole power fans especially airplane turning meeting angle air flying Fan fliers soon discovered smoothly radiused bellmouth duct entries boosted airflow raised efficiency eliminated much sensitivity sideward airflow Perhaps best way explaining action involved compare crowd people tossing Ping-Pong balls rapidly possible bottomless coffee can floor Balls go can fall through hole underneath miss nothing obby Line Model Airplanes Helicopters Boats Cars JAGUAR 4OARF Wing Span 48 Length 40 Weight 48 lbs- 57 lbs Item 865B ~33Oi9S PIPER CUB J-3/ARC 25-36 ALL WOOD CONST SAIE 5p1EWing Span 54 Length 36$5g9 qA95Weight 3 SIbs Iteme8S7-N PIPER CUB J-3/ARF 40 YELLOW/ ALL WOOD CONST Wing Span 67 Length 43 Weight 79 lbs Item#867 FIRE FLY ARF 10-15 20 GLOW INTHE DARK AFTER SUNSET 5plE Wing Span 48 Length 347 Weight 2 2 lbs 2 4 lbs Item #940 SKY BABY-S/ ARF 25-35 20 TRAINER 5M.E Wing Span 51 5 Length 36 Weight 3 3 lbs ltem#852 DEALERS AND DISTRIBUTORS INDUIRIES WELCOME QRDERLANLY 1-300-2494544 u TECH INFORMATION 1-201460-0544 OUR FAX LINE 1-2014604770 WE ACCEPT VISA EASTER CARD & DiSCOVER CARDS PRICES SUBJECT TO CHANGE WITHOUT NOTICE STORE HOURS MONDAY THRU THURSDAY 10AM TO 7 PM FRIDAY 10AM TO 9PM SATURDAYS lOAM TO 4PM PACKAGING AND SHIPPING Ftt 65 50 NEW JERStY RtSIDENTS ADD 6 SALES TAX _ US HOBBY INC 200 MOONACHIE AVE MOONACHIE NJ 07074 US HOBBY INC F7F Tigercat Wingspan inches Wing area807 sqinches Engines45-75 161-91 4 stroke Weight12-l4Ibs Radio 4 6 channel Kit Includes Fiberglass Fuselage Nacelles Foam Core Wing Stabelizer Clear Vacuum Formed Canopy wood parts complete kit $34999 orking Tomorrows Technology 140 S CamoSeco#415 Thcson AZ 85710 Phone/FAX 520 886-3678 HTTPJ/membersaolcom/jrcustom/indexhtmI /4 Qo 4OL4 SKT aABY-L/ARF 25-35 2C TRAINER SNIE Wing Span 51 5 Lengin 36 Weight 3 3 lbs Item 854 balls strike rim area just inside will bounce they interfere other incoming balls prevent some entering interference becomes worse balls being thrown angle can s axis Most go ricochet randomly can walls other produces near jam-up entry analogy balls represent molecules oxygen nitrogen C02 etc air Although terms inaccurate lets call air molecules bottomless coffee can entry ducted fan outer end model engine air intake jam-up entryway inlet stall Looking problem way its obvious make easy balls air molecules pass through opening opening should trumpet-shaped have gently-rounded edge balls molecules hit wall surfaces way will deflected slightly entry path No obstructive jam-up will clog inflow What happens model airplane engines air inlet has major effect its performance Its power depends optimum fuel-air mixture reaching combustion chamber has pass through intake passage first True some air can enter via subpiston induction Cox Tee Dees use feature subpiston gap narrow remains open exceedingly briefly less half millisecond TD 049 18K rpm much air can sneak engine flicker time know rear-rotary induction used record-setting racing engines eg McCoys Doolings instead far simpler front-rotary valve reason restricting intake diameter often cures erratic engine about getting good midrange settings such trick achieve RC barrel throttles Ill explain pointsand next column Until heres helpful tip Keep plastic bag type used supermarkets produce wrapped around nose of engine-powered models time its being flown simple step can add years engines lifespan light Training Beginner advanced tailored individual long-time modeler full size airplane flight instruc tor will make progress fun easy during week stay beautiful far western North Carolina Write call information RC Flight Training 1635 Setawig Rd Brasstown NC 28902 704-389-8968 GMS2000 proud announce arrival Crown Jewel lineup top quality engines GMS2000 120 2-stroke Light weight attention detail typical GMS engineering 2needle carburetor contribute continued success line already established unsurpassed GMS2000 40 47 2 year warranty excellent service support GMS2000 engines meant used seen sc International PO Box 40116 Indianapolis Indiana 46280 1317-844-1978 http//wwwiquestnetfisc North west Model Distribution 21527 NE 227th Battle Ground WA 98604 1-360687-9452
Edition: Model Aviation - 1997/11
Page Numbers: 83, 84, 85, 86, 89
Edition: Model Aviation - 1997/11
Page Numbers: 83, 84, 85, 86, 89
U Joe Wagner ANYTIME someone makes snide remark about toy airplanes might squelch fact model aircraft highest-powered propeller-driven vehicles existence thats narrow margin either Take speediest fastest-climbing prop-equipped fighter ever built Grummans F8F Bearcat weighed 9334 pounds 2800 horsepower Thats 31/3 pounds per horsepower Navy fighter version recent world-record-setting speciallymodified Rare Bear Bearcat came out somewhere around two pounds per horsepower Thats mighty impressive weight-to-power ratiountil consider todays competition Free Flight models nearly double typical 15-powered FlC FF entry weighs 27 ounces its engine develops about 11/2 horsepower works out fantastic 110 lb/hp reason incredible power levels todays Free Flight airplanes FF has effectively become racing eventthe race~ maximum vertical distance given time Competing requires much same sort power plants Control Line Speed extraordinary power output todays competition model airplane engines comes intensive design development very latest metallurgical advances high-nitro fuel rpm close-to-30OOO range earlier column mentioned Rule Thumb approximate maximum speed limit mph propdriven airplane equals propeller pitch inches times engine rpm thousands Thus CL Stunt model pulled 9 x 5 prop spinning 10000 rpm just cant travel about 50mph November 1997 83 MP Jet 061 Carison Engine Imports can used sport Control Line models competition Free Flight 1932 Brown 60 powered FF models up 10-foot wingspan yet developed less horspower some modern competition 05s RC FF versions Cox/K&B Conquest may have Americas highest-performing production-made 15 Foxs ball-bearing 25 puts out power runs reliably its famous shorter-intake ancestor Fox 35 want speed two ways get higher-pitch prop greater rpmand preferably both Notice horsepower engine develops doesnt enter directly relationship could have fourhorsepower chain saw engine model driving eight-inch-pitch prop regardless its diameter 9000 rpm aircraft couldnt exceed about 72 mph full-throttle dive Thats reason todays 30000 rpm model engines performance astounds 180 hp Rossi 21 26 hp MP Jet 061 course horsepower figures come dynamometer testing dont necessarily represent what happens flight example take Brown Junior 60 powered Joe Konefes Buzzard Bombshell its 49-minute flight won Class C Free Flight 1941 Nationals Brown put out well under 1/5 horsepower day Any new Russian competition /IA glow engines can outdo Yet installed say AME nose Joes famous prewar record-setter 30K rpm could barely manage taxi six-foot 31/2 pound thick-winged craft High rpms everything 84 Model Aviation uri extension Wagner-modified PAW 06 diesel eliminates Extended air intakes catching Heres Estes latest inlet stall problems sometimes encountered original version well-known Cox reed-valve product engine TRU-TURN now offers very finest versatile light weight PROP HUBS turned solid barstock inside out true running hub new hub will mount motor standard TRU-TURN adapter kit big bird multi-bolt applications TRU-TURN has covered n U S TRU-TURN also has PROP NUT will fit motor precision PROP NUTS come engine thread sizes two different shapes available stock Ask hobby dealer name z PRECISION MODEL PRODUCTS Romco Manufactu ng ncEli QUALITY VERSATILITY GREAT LOOKS SAFETY PO Box 836 South Houston Texas 77587 713 / 943 1867 need racing events ducted fans just about other kind model flying 15000 rpm plenty fast enough Thats what MP Jet 061 delivers 5% nitro fuel APC 7 x 3 prop providing close-to-ideal power small CL Stunt models High rpm has dangers too Propeller hub stresses increase square rpm centrifugal force alone fourth power Thats because additional thrust torque loads prop hub also go up square rpm increase model engine speed doubles eg 10K 20K rpm forces tending pull its prop apart increase sixteen times True modem propeller makers have beefed up products APC props have featured massive hubs right start Windsor Master Airscrew folks strengthened some months ago Fliers compete models using engines turn 30K rpm range would think trying props skimpy hubs guys pros know better Still theres always guy just loves hear engine shriek may tempted put plain nylon 7 x 4 honkin Conquest 15 see just fast itll spin Thats tragedy making Back Good Old Days sizable number us gas model fliers put fair amount time ingenuity hopping up engines Most effort did little good some did harm Still felt accomplishing something worthwhile really amounted personalizing power plants Theres always temptation mechanically minded people customize things like automobiles bikes computers boats model airplane engines todays everincreasing level technology its getting harder harder find ways improve itemsespecially ways within technical financial means However relatively simple highly beneficial modification can make model airplane engines boosts reliability usually adds power makes engine look noticeably different stock Extend venturi isnt new idea merely little-understood First investigated reported prewar British model engine expert Col C E Bowden lengthened air intakes never caught An enthusiastic article E C Ted Martin MAN 30 years ago also failed popularize improvement Now its turn try about 40 years Ive reworking customizing model engines time single beneficial change Ive ever found has adding venturi extensions Superior Balsa & Hobby SupplyGN & ORDER HOURS it Home Paget http//pw2/-balsalsupenorhtm ECTION 700 AM 700 020-G Centralia Street Hawaiian Gardens CA 9071650% SURCHARGE PST CA TIME FGRS & DEALERS Monday SaturdayPlease add sufficient amount excess refunded shipping UPS Parcel Post PLUS $285 handlingEND FOR RESELLER 800 488-9525 500 Mm order accept Visa Mastercard Checks CA sales add 825% sales tax GRAM Info 582865-3220 FAX 562860-0327 http//pw2lnetcomcom/balsalSuperiOrhtnlPilces sitect chn 3/97 E complete price list Shop hours 800AM 300PM Mon Fri BALSAspucrnss STICKSBALSA SHEETS TRAILING EDGES 36 LEADING EDGESAircraft Grade Birch yood 11160 129311603143547,.6x1212x12129241294848x48 DOUBLEBALSAPRICES164CM36481/8 o112Ii140 279 610 950 3600 STICKS3648 1/1664CM364811464CM36483132013142114 xl39 64 1/19o1/16101/4o 11422301/8 015/16x1-1/448 71 1/16x313210114031827333/16o1~318 01-1/256 853pjy 1/1601/810141/4x1/229411/4 xl92781/2 x2go 1/4x318 503/803/8751132 3/8 xl6786314 x3160 1/2 851/2x1/21053Ply95180335 6352475 1116x3116II151/4x5/837501/2 xl76104 1/20314145314x3/41601/16 1/16x1/41215l/4x3/44258264CM3641 31401170lxi1883My95180335 6252400 1/16o3151316 1/1601/217215/1664CM3648irzxxiu 36AILERONSMSLdgEd9eRetl6CtveT8p6 35U 1/16 x238 50 1/16x3/422295/16o9/1627353/22x246 611/4 xl57 3/3284CM36485/16o1/238483116x260741/4 xl-1/274WIDEBALSASHEETS1/8 3/32x 3/3211125/16x3144682114 x268601/4 x260145260550 9503800 3/320 1/812 14318 x2861199/16x1-1/476o36 8e38 j45 35fl.JJL 5/16031831 29118 x248851/4 xl-I/4 A60 135263 504 9753800 3/32x311613165/864CM36481/2 x21101435/l6x11/2751/161412282003183/16 3/3201/414183/8x31836455/iBo 28631321602472253454 Ply 99 185347 6892600 3/3203/815183/8x1/24057364CM3648318 01-1/2831/81792782503802/32x1/21824318x8/847581/32x34360318x2953116 206314285440125230 3807252850 3/32x3/42632318x31453681/160344603/8o2-1/21061/4 2353803255305PI 3/32 x 352671/2x1-1/295318 300477420665 3/8 1/864CM36481/8 x363841/2x21061/2 5105857158507py150285 55010003900 1/8x1/811131/201/249643/iBoS76103 1/8x311613181/2xS/857761/4 x394130 TRI 1/8x1/414211/2x31460825/160310915236ANGLESBALSABLOCKS200350 58011254300 1/8x3181523318 x31151701/401/429lxi 243030!t. 1/8x1/221275/564CM 36 x3 150 206 f%,068075060iiW 1/8 1/000428 365/8o5/860 86JCM3180318102 989 165 160215elosRy 751252354501700 1/201/240 5/Sol93 1141/22x46692314x3/4IN13120235285329i/8ute 3/1664CM56481/16x468lxi68I 04 157 325 376 425PoflIer751252354501700 311603/181423 Other Fine Products 3133482 1142x2 175 2A5 282330 3116x1/418 27 NHP West 4 160 423 1/4Lile Systems36 DOWELS2o4265460530715p 901753456502470 3/16X3182128& Bob Smith Epoxy3/1654109199 3/1601/22436 Tools Supplies1/4 041521791/8165/1627303330995750865 3116X3143045318 x4210285311617 3/8373x44607708201235OBECHI- 1/32x 14x lOS -$1475 Composits Hordware 1/2 04285 3361/4301/2 54 404 690 880 1290 1800 CAS Bob Smith Flash 36 Bargain Balsa Bundles $295 AM SHEETS 81u2x12x24 368 mc1/2oz210185Wlste2xl2x24 175 8ue2x24x48 1328 Gapor1 oz3493001/32x3 8 1/22x461/8x1/8383116x3116301/4x1/4 19318o3/812 1/201/2 8 Thick2oz5955001/16x3 8 1/16x461/8x3116323116x1/4231/4x318 15318x1/210 1/2x314 6 W14e2x24x48 630 EPP2x12x24 Thk8oz179516503/32x3 8 3/320451/8x1/4303116x31820l/4x1/2 143180314 81 0Al51O l6oz30001/8 03 6 1/8 x4 41/80318 128 3/1601/2 17 1/40314 10W14te4x12o24 350 EPP2x18O48 1 iii 2ozlhiop88og-1 seexweS50 31160315311604 31/801/2 20 31160314 13Limited availabilityCalI OdSIese 1/2oz4553651/4 03 4 1/4 0431/80314 15Denotesquaatityperbuadle/M4le4x24x48 1275 EPP2036x48 3000 1 oz845665 3/8 033318 042* Some stajas womiholes & mogiilaroIncoflel Foam CtJtSflg VVlre -8 feel $300 Tho$600 HartEg Oversize SNp9 C119e Thok2 OZ14951200 1/2 x3 2 1/204 2 Doing improves fuel draw combined smoothly contoured belimouth air inlet boosts running reliability adds power too Heres inlet port model engine two stroke four-stroke open just part shaft revolution Thats time air/fuel mixture can enter reason flow through entry port pulsates Pulsating airflow model engines intake detrimental because takes time flow get started up speed just incoming air/fuel flow gets moving along nicely engine its inlet closes cuts inflow off air/fuel mix approaching inlet port instant bounces back Its moving wrong way inlet port reopens has reverse again takes time Airflow oscillates inlet port costs power limits amount oxygen engine can inhale bum its fuel As fuel supply suction could hardly ask worse conditions delivering consistent reliable fuel flow pulsating vacuum spraybar orifice reason suction-feed model engine can overcome problem airstream passing through its venturi has both momentum compressibility inertia air accelerating inward through entry venturi tends keep going though flow other end stopand-go does compressing air ahead passageway passageway short amount air within given instant may have enough moving mass overcome pulsation engines inlet port Speeding up flow increases momentum however Thats source saying Model engines happier high rpm passageway long its different story Theres enough air mass moving within keep inflow steady low rpm reason todays RC engines idle much reliably yesteryear total inlet passage length greater theres venturi customizing story Theres also mysterious inlet stall phenomenon Probably first notice ill effects inlet stall ducted-fan fliers branch aeromodeling new experimenters found contour ducts entry much effect airflow through its cross-sectional area Sharpedged duct entries stole power fans especially airplane turning meeting angle air flying Fan fliers soon discovered smoothly radiused bellmouth duct entries boosted airflow raised efficiency eliminated much sensitivity sideward airflow Perhaps best way explaining action involved compare crowd people tossing Ping-Pong balls rapidly possible bottomless coffee can floor Balls go can fall through hole underneath miss nothing obby Line Model Airplanes Helicopters Boats Cars JAGUAR 4OARF Wing Span 48 Length 40 Weight 48 lbs- 57 lbs Item 865B ~33Oi9S PIPER CUB J-3/ARC 25-36 ALL WOOD CONST SAIE 5p1EWing Span 54 Length 36$5g9 qA95Weight 3 SIbs Iteme8S7-N PIPER CUB J-3/ARF 40 YELLOW/ ALL WOOD CONST Wing Span 67 Length 43 Weight 79 lbs Item#867 FIRE FLY ARF 10-15 20 GLOW INTHE DARK AFTER SUNSET 5plE Wing Span 48 Length 347 Weight 2 2 lbs 2 4 lbs Item #940 SKY BABY-S/ ARF 25-35 20 TRAINER 5M.E Wing Span 51 5 Length 36 Weight 3 3 lbs ltem#852 DEALERS AND DISTRIBUTORS INDUIRIES WELCOME QRDERLANLY 1-300-2494544 u TECH INFORMATION 1-201460-0544 OUR FAX LINE 1-2014604770 WE ACCEPT VISA EASTER CARD & DiSCOVER CARDS PRICES SUBJECT TO CHANGE WITHOUT NOTICE STORE HOURS MONDAY THRU THURSDAY 10AM TO 7 PM FRIDAY 10AM TO 9PM SATURDAYS lOAM TO 4PM PACKAGING AND SHIPPING Ftt 65 50 NEW JERStY RtSIDENTS ADD 6 SALES TAX _ US HOBBY INC 200 MOONACHIE AVE MOONACHIE NJ 07074 US HOBBY INC F7F Tigercat Wingspan inches Wing area807 sqinches Engines45-75 161-91 4 stroke Weight12-l4Ibs Radio 4 6 channel Kit Includes Fiberglass Fuselage Nacelles Foam Core Wing Stabelizer Clear Vacuum Formed Canopy wood parts complete kit $34999 orking Tomorrows Technology 140 S CamoSeco#415 Thcson AZ 85710 Phone/FAX 520 886-3678 HTTPJ/membersaolcom/jrcustom/indexhtmI /4 Qo 4OL4 SKT aABY-L/ARF 25-35 2C TRAINER SNIE Wing Span 51 5 Lengin 36 Weight 3 3 lbs Item 854 balls strike rim area just inside will bounce they interfere other incoming balls prevent some entering interference becomes worse balls being thrown angle can s axis Most go ricochet randomly can walls other produces near jam-up entry analogy balls represent molecules oxygen nitrogen C02 etc air Although terms inaccurate lets call air molecules bottomless coffee can entry ducted fan outer end model engine air intake jam-up entryway inlet stall Looking problem way its obvious make easy balls air molecules pass through opening opening should trumpet-shaped have gently-rounded edge balls molecules hit wall surfaces way will deflected slightly entry path No obstructive jam-up will clog inflow What happens model airplane engines air inlet has major effect its performance Its power depends optimum fuel-air mixture reaching combustion chamber has pass through intake passage first True some air can enter via subpiston induction Cox Tee Dees use feature subpiston gap narrow remains open exceedingly briefly less half millisecond TD 049 18K rpm much air can sneak engine flicker time know rear-rotary induction used record-setting racing engines eg McCoys Doolings instead far simpler front-rotary valve reason restricting intake diameter often cures erratic engine about getting good midrange settings such trick achieve RC barrel throttles Ill explain pointsand next column Until heres helpful tip Keep plastic bag type used supermarkets produce wrapped around nose of engine-powered models time its being flown simple step can add years engines lifespan light Training Beginner advanced tailored individual long-time modeler full size airplane flight instruc tor will make progress fun easy during week stay beautiful far western North Carolina Write call information RC Flight Training 1635 Setawig Rd Brasstown NC 28902 704-389-8968 GMS2000 proud announce arrival Crown Jewel lineup top quality engines GMS2000 120 2-stroke Light weight attention detail typical GMS engineering 2needle carburetor contribute continued success line already established unsurpassed GMS2000 40 47 2 year warranty excellent service support GMS2000 engines meant used seen sc International PO Box 40116 Indianapolis Indiana 46280 1317-844-1978 http//wwwiquestnetfisc North west Model Distribution 21527 NE 227th Battle Ground WA 98604 1-360687-9452
Edition: Model Aviation - 1997/11
Page Numbers: 83, 84, 85, 86, 89
U Joe Wagner ANYTIME someone makes snide remark about toy airplanes might squelch fact model aircraft highest-powered propeller-driven vehicles existence thats narrow margin either Take speediest fastest-climbing prop-equipped fighter ever built Grummans F8F Bearcat weighed 9334 pounds 2800 horsepower Thats 31/3 pounds per horsepower Navy fighter version recent world-record-setting speciallymodified Rare Bear Bearcat came out somewhere around two pounds per horsepower Thats mighty impressive weight-to-power ratiountil consider todays competition Free Flight models nearly double typical 15-powered FlC FF entry weighs 27 ounces its engine develops about 11/2 horsepower works out fantastic 110 lb/hp reason incredible power levels todays Free Flight airplanes FF has effectively become racing eventthe race~ maximum vertical distance given time Competing requires much same sort power plants Control Line Speed extraordinary power output todays competition model airplane engines comes intensive design development very latest metallurgical advances high-nitro fuel rpm close-to-30OOO range earlier column mentioned Rule Thumb approximate maximum speed limit mph propdriven airplane equals propeller pitch inches times engine rpm thousands Thus CL Stunt model pulled 9 x 5 prop spinning 10000 rpm just cant travel about 50mph November 1997 83 MP Jet 061 Carison Engine Imports can used sport Control Line models competition Free Flight 1932 Brown 60 powered FF models up 10-foot wingspan yet developed less horspower some modern competition 05s RC FF versions Cox/K&B Conquest may have Americas highest-performing production-made 15 Foxs ball-bearing 25 puts out power runs reliably its famous shorter-intake ancestor Fox 35 want speed two ways get higher-pitch prop greater rpmand preferably both Notice horsepower engine develops doesnt enter directly relationship could have fourhorsepower chain saw engine model driving eight-inch-pitch prop regardless its diameter 9000 rpm aircraft couldnt exceed about 72 mph full-throttle dive Thats reason todays 30000 rpm model engines performance astounds 180 hp Rossi 21 26 hp MP Jet 061 course horsepower figures come dynamometer testing dont necessarily represent what happens flight example take Brown Junior 60 powered Joe Konefes Buzzard Bombshell its 49-minute flight won Class C Free Flight 1941 Nationals Brown put out well under 1/5 horsepower day Any new Russian competition /IA glow engines can outdo Yet installed say AME nose Joes famous prewar record-setter 30K rpm could barely manage taxi six-foot 31/2 pound thick-winged craft High rpms everything 84 Model Aviation uri extension Wagner-modified PAW 06 diesel eliminates Extended air intakes catching Heres Estes latest inlet stall problems sometimes encountered original version well-known Cox reed-valve product engine TRU-TURN now offers very finest versatile light weight PROP HUBS turned solid barstock inside out true running hub new hub will mount motor standard TRU-TURN adapter kit big bird multi-bolt applications TRU-TURN has covered n U S TRU-TURN also has PROP NUT will fit motor precision PROP NUTS come engine thread sizes two different shapes available stock Ask hobby dealer name z PRECISION MODEL PRODUCTS Romco Manufactu ng ncEli QUALITY VERSATILITY GREAT LOOKS SAFETY PO Box 836 South Houston Texas 77587 713 / 943 1867 need racing events ducted fans just about other kind model flying 15000 rpm plenty fast enough Thats what MP Jet 061 delivers 5% nitro fuel APC 7 x 3 prop providing close-to-ideal power small CL Stunt models High rpm has dangers too Propeller hub stresses increase square rpm centrifugal force alone fourth power Thats because additional thrust torque loads prop hub also go up square rpm increase model engine speed doubles eg 10K 20K rpm forces tending pull its prop apart increase sixteen times True modem propeller makers have beefed up products APC props have featured massive hubs right start Windsor Master Airscrew folks strengthened some months ago Fliers compete models using engines turn 30K rpm range would think trying props skimpy hubs guys pros know better Still theres always guy just loves hear engine shriek may tempted put plain nylon 7 x 4 honkin Conquest 15 see just fast itll spin Thats tragedy making Back Good Old Days sizable number us gas model fliers put fair amount time ingenuity hopping up engines Most effort did little good some did harm Still felt accomplishing something worthwhile really amounted personalizing power plants Theres always temptation mechanically minded people customize things like automobiles bikes computers boats model airplane engines todays everincreasing level technology its getting harder harder find ways improve itemsespecially ways within technical financial means However relatively simple highly beneficial modification can make model airplane engines boosts reliability usually adds power makes engine look noticeably different stock Extend venturi isnt new idea merely little-understood First investigated reported prewar British model engine expert Col C E Bowden lengthened air intakes never caught An enthusiastic article E C Ted Martin MAN 30 years ago also failed popularize improvement Now its turn try about 40 years Ive reworking customizing model engines time single beneficial change Ive ever found has adding venturi extensions Superior Balsa & Hobby SupplyGN & ORDER HOURS it Home Paget http//pw2/-balsalsupenorhtm ECTION 700 AM 700 020-G Centralia Street Hawaiian Gardens CA 9071650% SURCHARGE PST CA TIME FGRS & DEALERS Monday SaturdayPlease add sufficient amount excess refunded shipping UPS Parcel Post PLUS $285 handlingEND FOR RESELLER 800 488-9525 500 Mm order accept Visa Mastercard Checks CA sales add 825% sales tax GRAM Info 582865-3220 FAX 562860-0327 http//pw2lnetcomcom/balsalSuperiOrhtnlPilces sitect chn 3/97 E complete price list Shop hours 800AM 300PM Mon Fri BALSAspucrnss STICKSBALSA SHEETS TRAILING EDGES 36 LEADING EDGESAircraft Grade Birch yood 11160 129311603143547,.6x1212x12129241294848x48 DOUBLEBALSAPRICES164CM36481/8 o112Ii140 279 610 950 3600 STICKS3648 1/1664CM364811464CM36483132013142114 xl39 64 1/19o1/16101/4o 11422301/8 015/16x1-1/448 71 1/16x313210114031827333/16o1~318 01-1/256 853pjy 1/1601/810141/4x1/229411/4 xl92781/2 x2go 1/4x318 503/803/8751132 3/8 xl6786314 x3160 1/2 851/2x1/21053Ply95180335 6352475 1116x3116II151/4x5/837501/2 xl76104 1/20314145314x3/41601/16 1/16x1/41215l/4x3/44258264CM3641 31401170lxi1883My95180335 6252400 1/16o3151316 1/1601/217215/1664CM3648irzxxiu 36AILERONSMSLdgEd9eRetl6CtveT8p6 35U 1/16 x238 50 1/16x3/422295/16o9/1627353/22x246 611/4 xl57 3/3284CM36485/16o1/238483116x260741/4 xl-1/274WIDEBALSASHEETS1/8 3/32x 3/3211125/16x3144682114 x268601/4 x260145260550 9503800 3/320 1/812 14318 x2861199/16x1-1/476o36 8e38 j45 35fl.JJL 5/16031831 29118 x248851/4 xl-I/4 A60 135263 504 9753800 3/32x311613165/864CM36481/2 x21101435/l6x11/2751/161412282003183/16 3/3201/414183/8x31836455/iBo 28631321602472253454 Ply 99 185347 6892600 3/3203/815183/8x1/24057364CM3648318 01-1/2831/81792782503802/32x1/21824318x8/847581/32x34360318x2953116 206314285440125230 3807252850 3/32x3/42632318x31453681/160344603/8o2-1/21061/4 2353803255305PI 3/32 x 352671/2x1-1/295318 300477420665 3/8 1/864CM36481/8 x363841/2x21061/2 5105857158507py150285 55010003900 1/8x1/811131/201/249643/iBoS76103 1/8x311613181/2xS/857761/4 x394130 TRI 1/8x1/414211/2x31460825/160310915236ANGLESBALSABLOCKS200350 58011254300 1/8x3181523318 x31151701/401/429lxi 243030!t. 1/8x1/221275/564CM 36 x3 150 206 f%,068075060iiW 1/8 1/000428 365/8o5/860 86JCM3180318102 989 165 160215elosRy 751252354501700 1/201/240 5/Sol93 1141/22x46692314x3/4IN13120235285329i/8ute 3/1664CM56481/16x468lxi68I 04 157 325 376 425PoflIer751252354501700 311603/181423 Other Fine Products 3133482 1142x2 175 2A5 282330 3116x1/418 27 NHP West 4 160 423 1/4Lile Systems36 DOWELS2o4265460530715p 901753456502470 3/16X3182128& Bob Smith Epoxy3/1654109199 3/1601/22436 Tools Supplies1/4 041521791/8165/1627303330995750865 3116X3143045318 x4210285311617 3/8373x44607708201235OBECHI- 1/32x 14x lOS -$1475 Composits Hordware 1/2 04285 3361/4301/2 54 404 690 880 1290 1800 CAS Bob Smith Flash 36 Bargain Balsa Bundles $295 AM SHEETS 81u2x12x24 368 mc1/2oz210185Wlste2xl2x24 175 8ue2x24x48 1328 Gapor1 oz3493001/32x3 8 1/22x461/8x1/8383116x3116301/4x1/4 19318o3/812 1/201/2 8 Thick2oz5955001/16x3 8 1/16x461/8x3116323116x1/4231/4x318 15318x1/210 1/2x314 6 W14e2x24x48 630 EPP2x12x24 Thk8oz179516503/32x3 8 3/320451/8x1/4303116x31820l/4x1/2 143180314 81 0Al51O l6oz30001/8 03 6 1/8 x4 41/80318 128 3/1601/2 17 1/40314 10W14te4x12o24 350 EPP2x18O48 1 iii 2ozlhiop88og-1 seexweS50 31160315311604 31/801/2 20 31160314 13Limited availabilityCalI OdSIese 1/2oz4553651/4 03 4 1/4 0431/80314 15Denotesquaatityperbuadle/M4le4x24x48 1275 EPP2036x48 3000 1 oz845665 3/8 033318 042* Some stajas womiholes & mogiilaroIncoflel Foam CtJtSflg VVlre -8 feel $300 Tho$600 HartEg Oversize SNp9 C119e Thok2 OZ14951200 1/2 x3 2 1/204 2 Doing improves fuel draw combined smoothly contoured belimouth air inlet boosts running reliability adds power too Heres inlet port model engine two stroke four-stroke open just part shaft revolution Thats time air/fuel mixture can enter reason flow through entry port pulsates Pulsating airflow model engines intake detrimental because takes time flow get started up speed just incoming air/fuel flow gets moving along nicely engine its inlet closes cuts inflow off air/fuel mix approaching inlet port instant bounces back Its moving wrong way inlet port reopens has reverse again takes time Airflow oscillates inlet port costs power limits amount oxygen engine can inhale bum its fuel As fuel supply suction could hardly ask worse conditions delivering consistent reliable fuel flow pulsating vacuum spraybar orifice reason suction-feed model engine can overcome problem airstream passing through its venturi has both momentum compressibility inertia air accelerating inward through entry venturi tends keep going though flow other end stopand-go does compressing air ahead passageway passageway short amount air within given instant may have enough moving mass overcome pulsation engines inlet port Speeding up flow increases momentum however Thats source saying Model engines happier high rpm passageway long its different story Theres enough air mass moving within keep inflow steady low rpm reason todays RC engines idle much reliably yesteryear total inlet passage length greater theres venturi customizing story Theres also mysterious inlet stall phenomenon Probably first notice ill effects inlet stall ducted-fan fliers branch aeromodeling new experimenters found contour ducts entry much effect airflow through its cross-sectional area Sharpedged duct entries stole power fans especially airplane turning meeting angle air flying Fan fliers soon discovered smoothly radiused bellmouth duct entries boosted airflow raised efficiency eliminated much sensitivity sideward airflow Perhaps best way explaining action involved compare crowd people tossing Ping-Pong balls rapidly possible bottomless coffee can floor Balls go can fall through hole underneath miss nothing obby Line Model Airplanes Helicopters Boats Cars JAGUAR 4OARF Wing Span 48 Length 40 Weight 48 lbs- 57 lbs Item 865B ~33Oi9S PIPER CUB J-3/ARC 25-36 ALL WOOD CONST SAIE 5p1EWing Span 54 Length 36$5g9 qA95Weight 3 SIbs Iteme8S7-N PIPER CUB J-3/ARF 40 YELLOW/ ALL WOOD CONST Wing Span 67 Length 43 Weight 79 lbs Item#867 FIRE FLY ARF 10-15 20 GLOW INTHE DARK AFTER SUNSET 5plE Wing Span 48 Length 347 Weight 2 2 lbs 2 4 lbs Item #940 SKY BABY-S/ ARF 25-35 20 TRAINER 5M.E Wing Span 51 5 Length 36 Weight 3 3 lbs ltem#852 DEALERS AND DISTRIBUTORS INDUIRIES WELCOME QRDERLANLY 1-300-2494544 u TECH INFORMATION 1-201460-0544 OUR FAX LINE 1-2014604770 WE ACCEPT VISA EASTER CARD & DiSCOVER CARDS PRICES SUBJECT TO CHANGE WITHOUT NOTICE STORE HOURS MONDAY THRU THURSDAY 10AM TO 7 PM FRIDAY 10AM TO 9PM SATURDAYS lOAM TO 4PM PACKAGING AND SHIPPING Ftt 65 50 NEW JERStY RtSIDENTS ADD 6 SALES TAX _ US HOBBY INC 200 MOONACHIE AVE MOONACHIE NJ 07074 US HOBBY INC F7F Tigercat Wingspan inches Wing area807 sqinches Engines45-75 161-91 4 stroke Weight12-l4Ibs Radio 4 6 channel Kit Includes Fiberglass Fuselage Nacelles Foam Core Wing Stabelizer Clear Vacuum Formed Canopy wood parts complete kit $34999 orking Tomorrows Technology 140 S CamoSeco#415 Thcson AZ 85710 Phone/FAX 520 886-3678 HTTPJ/membersaolcom/jrcustom/indexhtmI /4 Qo 4OL4 SKT aABY-L/ARF 25-35 2C TRAINER SNIE Wing Span 51 5 Lengin 36 Weight 3 3 lbs Item 854 balls strike rim area just inside will bounce they interfere other incoming balls prevent some entering interference becomes worse balls being thrown angle can s axis Most go ricochet randomly can walls other produces near jam-up entry analogy balls represent molecules oxygen nitrogen C02 etc air Although terms inaccurate lets call air molecules bottomless coffee can entry ducted fan outer end model engine air intake jam-up entryway inlet stall Looking problem way its obvious make easy balls air molecules pass through opening opening should trumpet-shaped have gently-rounded edge balls molecules hit wall surfaces way will deflected slightly entry path No obstructive jam-up will clog inflow What happens model airplane engines air inlet has major effect its performance Its power depends optimum fuel-air mixture reaching combustion chamber has pass through intake passage first True some air can enter via subpiston induction Cox Tee Dees use feature subpiston gap narrow remains open exceedingly briefly less half millisecond TD 049 18K rpm much air can sneak engine flicker time know rear-rotary induction used record-setting racing engines eg McCoys Doolings instead far simpler front-rotary valve reason restricting intake diameter often cures erratic engine about getting good midrange settings such trick achieve RC barrel throttles Ill explain pointsand next column Until heres helpful tip Keep plastic bag type used supermarkets produce wrapped around nose of engine-powered models time its being flown simple step can add years engines lifespan light Training Beginner advanced tailored individual long-time modeler full size airplane flight instruc tor will make progress fun easy during week stay beautiful far western North Carolina Write call information RC Flight Training 1635 Setawig Rd Brasstown NC 28902 704-389-8968 GMS2000 proud announce arrival Crown Jewel lineup top quality engines GMS2000 120 2-stroke Light weight attention detail typical GMS engineering 2needle carburetor contribute continued success line already established unsurpassed GMS2000 40 47 2 year warranty excellent service support GMS2000 engines meant used seen sc International PO Box 40116 Indianapolis Indiana 46280 1317-844-1978 http//wwwiquestnetfisc North west Model Distribution 21527 NE 227th Battle Ground WA 98604 1-360687-9452
Edition: Model Aviation - 1997/11
Page Numbers: 83, 84, 85, 86, 89
U Joe Wagner ANYTIME someone makes snide remark about toy airplanes might squelch fact model aircraft highest-powered propeller-driven vehicles existence thats narrow margin either Take speediest fastest-climbing prop-equipped fighter ever built Grummans F8F Bearcat weighed 9334 pounds 2800 horsepower Thats 31/3 pounds per horsepower Navy fighter version recent world-record-setting speciallymodified Rare Bear Bearcat came out somewhere around two pounds per horsepower Thats mighty impressive weight-to-power ratiountil consider todays competition Free Flight models nearly double typical 15-powered FlC FF entry weighs 27 ounces its engine develops about 11/2 horsepower works out fantastic 110 lb/hp reason incredible power levels todays Free Flight airplanes FF has effectively become racing eventthe race~ maximum vertical distance given time Competing requires much same sort power plants Control Line Speed extraordinary power output todays competition model airplane engines comes intensive design development very latest metallurgical advances high-nitro fuel rpm close-to-30OOO range earlier column mentioned Rule Thumb approximate maximum speed limit mph propdriven airplane equals propeller pitch inches times engine rpm thousands Thus CL Stunt model pulled 9 x 5 prop spinning 10000 rpm just cant travel about 50mph November 1997 83 MP Jet 061 Carison Engine Imports can used sport Control Line models competition Free Flight 1932 Brown 60 powered FF models up 10-foot wingspan yet developed less horspower some modern competition 05s RC FF versions Cox/K&B Conquest may have Americas highest-performing production-made 15 Foxs ball-bearing 25 puts out power runs reliably its famous shorter-intake ancestor Fox 35 want speed two ways get higher-pitch prop greater rpmand preferably both Notice horsepower engine develops doesnt enter directly relationship could have fourhorsepower chain saw engine model driving eight-inch-pitch prop regardless its diameter 9000 rpm aircraft couldnt exceed about 72 mph full-throttle dive Thats reason todays 30000 rpm model engines performance astounds 180 hp Rossi 21 26 hp MP Jet 061 course horsepower figures come dynamometer testing dont necessarily represent what happens flight example take Brown Junior 60 powered Joe Konefes Buzzard Bombshell its 49-minute flight won Class C Free Flight 1941 Nationals Brown put out well under 1/5 horsepower day Any new Russian competition /IA glow engines can outdo Yet installed say AME nose Joes famous prewar record-setter 30K rpm could barely manage taxi six-foot 31/2 pound thick-winged craft High rpms everything 84 Model Aviation uri extension Wagner-modified PAW 06 diesel eliminates Extended air intakes catching Heres Estes latest inlet stall problems sometimes encountered original version well-known Cox reed-valve product engine TRU-TURN now offers very finest versatile light weight PROP HUBS turned solid barstock inside out true running hub new hub will mount motor standard TRU-TURN adapter kit big bird multi-bolt applications TRU-TURN has covered n U S TRU-TURN also has PROP NUT will fit motor precision PROP NUTS come engine thread sizes two different shapes available stock Ask hobby dealer name z PRECISION MODEL PRODUCTS Romco Manufactu ng ncEli QUALITY VERSATILITY GREAT LOOKS SAFETY PO Box 836 South Houston Texas 77587 713 / 943 1867 need racing events ducted fans just about other kind model flying 15000 rpm plenty fast enough Thats what MP Jet 061 delivers 5% nitro fuel APC 7 x 3 prop providing close-to-ideal power small CL Stunt models High rpm has dangers too Propeller hub stresses increase square rpm centrifugal force alone fourth power Thats because additional thrust torque loads prop hub also go up square rpm increase model engine speed doubles eg 10K 20K rpm forces tending pull its prop apart increase sixteen times True modem propeller makers have beefed up products APC props have featured massive hubs right start Windsor Master Airscrew folks strengthened some months ago Fliers compete models using engines turn 30K rpm range would think trying props skimpy hubs guys pros know better Still theres always guy just loves hear engine shriek may tempted put plain nylon 7 x 4 honkin Conquest 15 see just fast itll spin Thats tragedy making Back Good Old Days sizable number us gas model fliers put fair amount time ingenuity hopping up engines Most effort did little good some did harm Still felt accomplishing something worthwhile really amounted personalizing power plants Theres always temptation mechanically minded people customize things like automobiles bikes computers boats model airplane engines todays everincreasing level technology its getting harder harder find ways improve itemsespecially ways within technical financial means However relatively simple highly beneficial modification can make model airplane engines boosts reliability usually adds power makes engine look noticeably different stock Extend venturi isnt new idea merely little-understood First investigated reported prewar British model engine expert Col C E Bowden lengthened air intakes never caught An enthusiastic article E C Ted Martin MAN 30 years ago also failed popularize improvement Now its turn try about 40 years Ive reworking customizing model engines time single beneficial change Ive ever found has adding venturi extensions Superior Balsa & Hobby SupplyGN & ORDER HOURS it Home Paget http//pw2/-balsalsupenorhtm ECTION 700 AM 700 020-G Centralia Street Hawaiian Gardens CA 9071650% SURCHARGE PST CA TIME FGRS & DEALERS Monday SaturdayPlease add sufficient amount excess refunded shipping UPS Parcel Post PLUS $285 handlingEND FOR RESELLER 800 488-9525 500 Mm order accept Visa Mastercard Checks CA sales add 825% sales tax GRAM Info 582865-3220 FAX 562860-0327 http//pw2lnetcomcom/balsalSuperiOrhtnlPilces sitect chn 3/97 E complete price list Shop hours 800AM 300PM Mon Fri BALSAspucrnss STICKSBALSA SHEETS TRAILING EDGES 36 LEADING EDGESAircraft Grade Birch yood 11160 129311603143547,.6x1212x12129241294848x48 DOUBLEBALSAPRICES164CM36481/8 o112Ii140 279 610 950 3600 STICKS3648 1/1664CM364811464CM36483132013142114 xl39 64 1/19o1/16101/4o 11422301/8 015/16x1-1/448 71 1/16x313210114031827333/16o1~318 01-1/256 853pjy 1/1601/810141/4x1/229411/4 xl92781/2 x2go 1/4x318 503/803/8751132 3/8 xl6786314 x3160 1/2 851/2x1/21053Ply95180335 6352475 1116x3116II151/4x5/837501/2 xl76104 1/20314145314x3/41601/16 1/16x1/41215l/4x3/44258264CM3641 31401170lxi1883My95180335 6252400 1/16o3151316 1/1601/217215/1664CM3648irzxxiu 36AILERONSMSLdgEd9eRetl6CtveT8p6 35U 1/16 x238 50 1/16x3/422295/16o9/1627353/22x246 611/4 xl57 3/3284CM36485/16o1/238483116x260741/4 xl-1/274WIDEBALSASHEETS1/8 3/32x 3/3211125/16x3144682114 x268601/4 x260145260550 9503800 3/320 1/812 14318 x2861199/16x1-1/476o36 8e38 j45 35fl.JJL 5/16031831 29118 x248851/4 xl-I/4 A60 135263 504 9753800 3/32x311613165/864CM36481/2 x21101435/l6x11/2751/161412282003183/16 3/3201/414183/8x31836455/iBo 28631321602472253454 Ply 99 185347 6892600 3/3203/815183/8x1/24057364CM3648318 01-1/2831/81792782503802/32x1/21824318x8/847581/32x34360318x2953116 206314285440125230 3807252850 3/32x3/42632318x31453681/160344603/8o2-1/21061/4 2353803255305PI 3/32 x 352671/2x1-1/295318 300477420665 3/8 1/864CM36481/8 x363841/2x21061/2 5105857158507py150285 55010003900 1/8x1/811131/201/249643/iBoS76103 1/8x311613181/2xS/857761/4 x394130 TRI 1/8x1/414211/2x31460825/160310915236ANGLESBALSABLOCKS200350 58011254300 1/8x3181523318 x31151701/401/429lxi 243030!t. 1/8x1/221275/564CM 36 x3 150 206 f%,068075060iiW 1/8 1/000428 365/8o5/860 86JCM3180318102 989 165 160215elosRy 751252354501700 1/201/240 5/Sol93 1141/22x46692314x3/4IN13120235285329i/8ute 3/1664CM56481/16x468lxi68I 04 157 325 376 425PoflIer751252354501700 311603/181423 Other Fine Products 3133482 1142x2 175 2A5 282330 3116x1/418 27 NHP West 4 160 423 1/4Lile Systems36 DOWELS2o4265460530715p 901753456502470 3/16X3182128& Bob Smith Epoxy3/1654109199 3/1601/22436 Tools Supplies1/4 041521791/8165/1627303330995750865 3116X3143045318 x4210285311617 3/8373x44607708201235OBECHI- 1/32x 14x lOS -$1475 Composits Hordware 1/2 04285 3361/4301/2 54 404 690 880 1290 1800 CAS Bob Smith Flash 36 Bargain Balsa Bundles $295 AM SHEETS 81u2x12x24 368 mc1/2oz210185Wlste2xl2x24 175 8ue2x24x48 1328 Gapor1 oz3493001/32x3 8 1/22x461/8x1/8383116x3116301/4x1/4 19318o3/812 1/201/2 8 Thick2oz5955001/16x3 8 1/16x461/8x3116323116x1/4231/4x318 15318x1/210 1/2x314 6 W14e2x24x48 630 EPP2x12x24 Thk8oz179516503/32x3 8 3/320451/8x1/4303116x31820l/4x1/2 143180314 81 0Al51O l6oz30001/8 03 6 1/8 x4 41/80318 128 3/1601/2 17 1/40314 10W14te4x12o24 350 EPP2x18O48 1 iii 2ozlhiop88og-1 seexweS50 31160315311604 31/801/2 20 31160314 13Limited availabilityCalI OdSIese 1/2oz4553651/4 03 4 1/4 0431/80314 15Denotesquaatityperbuadle/M4le4x24x48 1275 EPP2036x48 3000 1 oz845665 3/8 033318 042* Some stajas womiholes & mogiilaroIncoflel Foam CtJtSflg VVlre -8 feel $300 Tho$600 HartEg Oversize SNp9 C119e Thok2 OZ14951200 1/2 x3 2 1/204 2 Doing improves fuel draw combined smoothly contoured belimouth air inlet boosts running reliability adds power too Heres inlet port model engine two stroke four-stroke open just part shaft revolution Thats time air/fuel mixture can enter reason flow through entry port pulsates Pulsating airflow model engines intake detrimental because takes time flow get started up speed just incoming air/fuel flow gets moving along nicely engine its inlet closes cuts inflow off air/fuel mix approaching inlet port instant bounces back Its moving wrong way inlet port reopens has reverse again takes time Airflow oscillates inlet port costs power limits amount oxygen engine can inhale bum its fuel As fuel supply suction could hardly ask worse conditions delivering consistent reliable fuel flow pulsating vacuum spraybar orifice reason suction-feed model engine can overcome problem airstream passing through its venturi has both momentum compressibility inertia air accelerating inward through entry venturi tends keep going though flow other end stopand-go does compressing air ahead passageway passageway short amount air within given instant may have enough moving mass overcome pulsation engines inlet port Speeding up flow increases momentum however Thats source saying Model engines happier high rpm passageway long its different story Theres enough air mass moving within keep inflow steady low rpm reason todays RC engines idle much reliably yesteryear total inlet passage length greater theres venturi customizing story Theres also mysterious inlet stall phenomenon Probably first notice ill effects inlet stall ducted-fan fliers branch aeromodeling new experimenters found contour ducts entry much effect airflow through its cross-sectional area Sharpedged duct entries stole power fans especially airplane turning meeting angle air flying Fan fliers soon discovered smoothly radiused bellmouth duct entries boosted airflow raised efficiency eliminated much sensitivity sideward airflow Perhaps best way explaining action involved compare crowd people tossing Ping-Pong balls rapidly possible bottomless coffee can floor Balls go can fall through hole underneath miss nothing obby Line Model Airplanes Helicopters Boats Cars JAGUAR 4OARF Wing Span 48 Length 40 Weight 48 lbs- 57 lbs Item 865B ~33Oi9S PIPER CUB J-3/ARC 25-36 ALL WOOD CONST SAIE 5p1EWing Span 54 Length 36$5g9 qA95Weight 3 SIbs Iteme8S7-N PIPER CUB J-3/ARF 40 YELLOW/ ALL WOOD CONST Wing Span 67 Length 43 Weight 79 lbs Item#867 FIRE FLY ARF 10-15 20 GLOW INTHE DARK AFTER SUNSET 5plE Wing Span 48 Length 347 Weight 2 2 lbs 2 4 lbs Item #940 SKY BABY-S/ ARF 25-35 20 TRAINER 5M.E Wing Span 51 5 Length 36 Weight 3 3 lbs ltem#852 DEALERS AND DISTRIBUTORS INDUIRIES WELCOME QRDERLANLY 1-300-2494544 u TECH INFORMATION 1-201460-0544 OUR FAX LINE 1-2014604770 WE ACCEPT VISA EASTER CARD & DiSCOVER CARDS PRICES SUBJECT TO CHANGE WITHOUT NOTICE STORE HOURS MONDAY THRU THURSDAY 10AM TO 7 PM FRIDAY 10AM TO 9PM SATURDAYS lOAM TO 4PM PACKAGING AND SHIPPING Ftt 65 50 NEW JERStY RtSIDENTS ADD 6 SALES TAX _ US HOBBY INC 200 MOONACHIE AVE MOONACHIE NJ 07074 US HOBBY INC F7F Tigercat Wingspan inches Wing area807 sqinches Engines45-75 161-91 4 stroke Weight12-l4Ibs Radio 4 6 channel Kit Includes Fiberglass Fuselage Nacelles Foam Core Wing Stabelizer Clear Vacuum Formed Canopy wood parts complete kit $34999 orking Tomorrows Technology 140 S CamoSeco#415 Thcson AZ 85710 Phone/FAX 520 886-3678 HTTPJ/membersaolcom/jrcustom/indexhtmI /4 Qo 4OL4 SKT aABY-L/ARF 25-35 2C TRAINER SNIE Wing Span 51 5 Lengin 36 Weight 3 3 lbs Item 854 balls strike rim area just inside will bounce they interfere other incoming balls prevent some entering interference becomes worse balls being thrown angle can s axis Most go ricochet randomly can walls other produces near jam-up entry analogy balls represent molecules oxygen nitrogen C02 etc air Although terms inaccurate lets call air molecules bottomless coffee can entry ducted fan outer end model engine air intake jam-up entryway inlet stall Looking problem way its obvious make easy balls air molecules pass through opening opening should trumpet-shaped have gently-rounded edge balls molecules hit wall surfaces way will deflected slightly entry path No obstructive jam-up will clog inflow What happens model airplane engines air inlet has major effect its performance Its power depends optimum fuel-air mixture reaching combustion chamber has pass through intake passage first True some air can enter via subpiston induction Cox Tee Dees use feature subpiston gap narrow remains open exceedingly briefly less half millisecond TD 049 18K rpm much air can sneak engine flicker time know rear-rotary induction used record-setting racing engines eg McCoys Doolings instead far simpler front-rotary valve reason restricting intake diameter often cures erratic engine about getting good midrange settings such trick achieve RC barrel throttles Ill explain pointsand next column Until heres helpful tip Keep plastic bag type used supermarkets produce wrapped around nose of engine-powered models time its being flown simple step can add years engines lifespan light Training Beginner advanced tailored individual long-time modeler full size airplane flight instruc tor will make progress fun easy during week stay beautiful far western North Carolina Write call information RC Flight Training 1635 Setawig Rd Brasstown NC 28902 704-389-8968 GMS2000 proud announce arrival Crown Jewel lineup top quality engines GMS2000 120 2-stroke Light weight attention detail typical GMS engineering 2needle carburetor contribute continued success line already established unsurpassed GMS2000 40 47 2 year warranty excellent service support GMS2000 engines meant used seen sc International PO Box 40116 Indianapolis Indiana 46280 1317-844-1978 http//wwwiquestnetfisc North west Model Distribution 21527 NE 227th Battle Ground WA 98604 1-360687-9452
Edition: Model Aviation - 1997/11
Page Numbers: 83, 84, 85, 86, 89
U Joe Wagner ANYTIME someone makes snide remark about toy airplanes might squelch fact model aircraft highest-powered propeller-driven vehicles existence thats narrow margin either Take speediest fastest-climbing prop-equipped fighter ever built Grummans F8F Bearcat weighed 9334 pounds 2800 horsepower Thats 31/3 pounds per horsepower Navy fighter version recent world-record-setting speciallymodified Rare Bear Bearcat came out somewhere around two pounds per horsepower Thats mighty impressive weight-to-power ratiountil consider todays competition Free Flight models nearly double typical 15-powered FlC FF entry weighs 27 ounces its engine develops about 11/2 horsepower works out fantastic 110 lb/hp reason incredible power levels todays Free Flight airplanes FF has effectively become racing eventthe race~ maximum vertical distance given time Competing requires much same sort power plants Control Line Speed extraordinary power output todays competition model airplane engines comes intensive design development very latest metallurgical advances high-nitro fuel rpm close-to-30OOO range earlier column mentioned Rule Thumb approximate maximum speed limit mph propdriven airplane equals propeller pitch inches times engine rpm thousands Thus CL Stunt model pulled 9 x 5 prop spinning 10000 rpm just cant travel about 50mph November 1997 83 MP Jet 061 Carison Engine Imports can used sport Control Line models competition Free Flight 1932 Brown 60 powered FF models up 10-foot wingspan yet developed less horspower some modern competition 05s RC FF versions Cox/K&B Conquest may have Americas highest-performing production-made 15 Foxs ball-bearing 25 puts out power runs reliably its famous shorter-intake ancestor Fox 35 want speed two ways get higher-pitch prop greater rpmand preferably both Notice horsepower engine develops doesnt enter directly relationship could have fourhorsepower chain saw engine model driving eight-inch-pitch prop regardless its diameter 9000 rpm aircraft couldnt exceed about 72 mph full-throttle dive Thats reason todays 30000 rpm model engines performance astounds 180 hp Rossi 21 26 hp MP Jet 061 course horsepower figures come dynamometer testing dont necessarily represent what happens flight example take Brown Junior 60 powered Joe Konefes Buzzard Bombshell its 49-minute flight won Class C Free Flight 1941 Nationals Brown put out well under 1/5 horsepower day Any new Russian competition /IA glow engines can outdo Yet installed say AME nose Joes famous prewar record-setter 30K rpm could barely manage taxi six-foot 31/2 pound thick-winged craft High rpms everything 84 Model Aviation uri extension Wagner-modified PAW 06 diesel eliminates Extended air intakes catching Heres Estes latest inlet stall problems sometimes encountered original version well-known Cox reed-valve product engine TRU-TURN now offers very finest versatile light weight PROP HUBS turned solid barstock inside out true running hub new hub will mount motor standard TRU-TURN adapter kit big bird multi-bolt applications TRU-TURN has covered n U S TRU-TURN also has PROP NUT will fit motor precision PROP NUTS come engine thread sizes two different shapes available stock Ask hobby dealer name z PRECISION MODEL PRODUCTS Romco Manufactu ng ncEli QUALITY VERSATILITY GREAT LOOKS SAFETY PO Box 836 South Houston Texas 77587 713 / 943 1867 need racing events ducted fans just about other kind model flying 15000 rpm plenty fast enough Thats what MP Jet 061 delivers 5% nitro fuel APC 7 x 3 prop providing close-to-ideal power small CL Stunt models High rpm has dangers too Propeller hub stresses increase square rpm centrifugal force alone fourth power Thats because additional thrust torque loads prop hub also go up square rpm increase model engine speed doubles eg 10K 20K rpm forces tending pull its prop apart increase sixteen times True modem propeller makers have beefed up products APC props have featured massive hubs right start Windsor Master Airscrew folks strengthened some months ago Fliers compete models using engines turn 30K rpm range would think trying props skimpy hubs guys pros know better Still theres always guy just loves hear engine shriek may tempted put plain nylon 7 x 4 honkin Conquest 15 see just fast itll spin Thats tragedy making Back Good Old Days sizable number us gas model fliers put fair amount time ingenuity hopping up engines Most effort did little good some did harm Still felt accomplishing something worthwhile really amounted personalizing power plants Theres always temptation mechanically minded people customize things like automobiles bikes computers boats model airplane engines todays everincreasing level technology its getting harder harder find ways improve itemsespecially ways within technical financial means However relatively simple highly beneficial modification can make model airplane engines boosts reliability usually adds power makes engine look noticeably different stock Extend venturi isnt new idea merely little-understood First investigated reported prewar British model engine expert Col C E Bowden lengthened air intakes never caught An enthusiastic article E C Ted Martin MAN 30 years ago also failed popularize improvement Now its turn try about 40 years Ive reworking customizing model engines time single beneficial change Ive ever found has adding venturi extensions Superior Balsa & Hobby SupplyGN & ORDER HOURS it Home Paget http//pw2/-balsalsupenorhtm ECTION 700 AM 700 020-G Centralia Street Hawaiian Gardens CA 9071650% SURCHARGE PST CA TIME FGRS & DEALERS Monday SaturdayPlease add sufficient amount excess refunded shipping UPS Parcel Post PLUS $285 handlingEND FOR RESELLER 800 488-9525 500 Mm order accept Visa Mastercard Checks CA sales add 825% sales tax GRAM Info 582865-3220 FAX 562860-0327 http//pw2lnetcomcom/balsalSuperiOrhtnlPilces sitect chn 3/97 E complete price list Shop hours 800AM 300PM Mon Fri BALSAspucrnss STICKSBALSA SHEETS TRAILING EDGES 36 LEADING EDGESAircraft Grade Birch yood 11160 129311603143547,.6x1212x12129241294848x48 DOUBLEBALSAPRICES164CM36481/8 o112Ii140 279 610 950 3600 STICKS3648 1/1664CM364811464CM36483132013142114 xl39 64 1/19o1/16101/4o 11422301/8 015/16x1-1/448 71 1/16x313210114031827333/16o1~318 01-1/256 853pjy 1/1601/810141/4x1/229411/4 xl92781/2 x2go 1/4x318 503/803/8751132 3/8 xl6786314 x3160 1/2 851/2x1/21053Ply95180335 6352475 1116x3116II151/4x5/837501/2 xl76104 1/20314145314x3/41601/16 1/16x1/41215l/4x3/44258264CM3641 31401170lxi1883My95180335 6252400 1/16o3151316 1/1601/217215/1664CM3648irzxxiu 36AILERONSMSLdgEd9eRetl6CtveT8p6 35U 1/16 x238 50 1/16x3/422295/16o9/1627353/22x246 611/4 xl57 3/3284CM36485/16o1/238483116x260741/4 xl-1/274WIDEBALSASHEETS1/8 3/32x 3/3211125/16x3144682114 x268601/4 x260145260550 9503800 3/320 1/812 14318 x2861199/16x1-1/476o36 8e38 j45 35fl.JJL 5/16031831 29118 x248851/4 xl-I/4 A60 135263 504 9753800 3/32x311613165/864CM36481/2 x21101435/l6x11/2751/161412282003183/16 3/3201/414183/8x31836455/iBo 28631321602472253454 Ply 99 185347 6892600 3/3203/815183/8x1/24057364CM3648318 01-1/2831/81792782503802/32x1/21824318x8/847581/32x34360318x2953116 206314285440125230 3807252850 3/32x3/42632318x31453681/160344603/8o2-1/21061/4 2353803255305PI 3/32 x 352671/2x1-1/295318 300477420665 3/8 1/864CM36481/8 x363841/2x21061/2 5105857158507py150285 55010003900 1/8x1/811131/201/249643/iBoS76103 1/8x311613181/2xS/857761/4 x394130 TRI 1/8x1/414211/2x31460825/160310915236ANGLESBALSABLOCKS200350 58011254300 1/8x3181523318 x31151701/401/429lxi 243030!t. 1/8x1/221275/564CM 36 x3 150 206 f%,068075060iiW 1/8 1/000428 365/8o5/860 86JCM3180318102 989 165 160215elosRy 751252354501700 1/201/240 5/Sol93 1141/22x46692314x3/4IN13120235285329i/8ute 3/1664CM56481/16x468lxi68I 04 157 325 376 425PoflIer751252354501700 311603/181423 Other Fine Products 3133482 1142x2 175 2A5 282330 3116x1/418 27 NHP West 4 160 423 1/4Lile Systems36 DOWELS2o4265460530715p 901753456502470 3/16X3182128& Bob Smith Epoxy3/1654109199 3/1601/22436 Tools Supplies1/4 041521791/8165/1627303330995750865 3116X3143045318 x4210285311617 3/8373x44607708201235OBECHI- 1/32x 14x lOS -$1475 Composits Hordware 1/2 04285 3361/4301/2 54 404 690 880 1290 1800 CAS Bob Smith Flash 36 Bargain Balsa Bundles $295 AM SHEETS 81u2x12x24 368 mc1/2oz210185Wlste2xl2x24 175 8ue2x24x48 1328 Gapor1 oz3493001/32x3 8 1/22x461/8x1/8383116x3116301/4x1/4 19318o3/812 1/201/2 8 Thick2oz5955001/16x3 8 1/16x461/8x3116323116x1/4231/4x318 15318x1/210 1/2x314 6 W14e2x24x48 630 EPP2x12x24 Thk8oz179516503/32x3 8 3/320451/8x1/4303116x31820l/4x1/2 143180314 81 0Al51O l6oz30001/8 03 6 1/8 x4 41/80318 128 3/1601/2 17 1/40314 10W14te4x12o24 350 EPP2x18O48 1 iii 2ozlhiop88og-1 seexweS50 31160315311604 31/801/2 20 31160314 13Limited availabilityCalI OdSIese 1/2oz4553651/4 03 4 1/4 0431/80314 15Denotesquaatityperbuadle/M4le4x24x48 1275 EPP2036x48 3000 1 oz845665 3/8 033318 042* Some stajas womiholes & mogiilaroIncoflel Foam CtJtSflg VVlre -8 feel $300 Tho$600 HartEg Oversize SNp9 C119e Thok2 OZ14951200 1/2 x3 2 1/204 2 Doing improves fuel draw combined smoothly contoured belimouth air inlet boosts running reliability adds power too Heres inlet port model engine two stroke four-stroke open just part shaft revolution Thats time air/fuel mixture can enter reason flow through entry port pulsates Pulsating airflow model engines intake detrimental because takes time flow get started up speed just incoming air/fuel flow gets moving along nicely engine its inlet closes cuts inflow off air/fuel mix approaching inlet port instant bounces back Its moving wrong way inlet port reopens has reverse again takes time Airflow oscillates inlet port costs power limits amount oxygen engine can inhale bum its fuel As fuel supply suction could hardly ask worse conditions delivering consistent reliable fuel flow pulsating vacuum spraybar orifice reason suction-feed model engine can overcome problem airstream passing through its venturi has both momentum compressibility inertia air accelerating inward through entry venturi tends keep going though flow other end stopand-go does compressing air ahead passageway passageway short amount air within given instant may have enough moving mass overcome pulsation engines inlet port Speeding up flow increases momentum however Thats source saying Model engines happier high rpm passageway long its different story Theres enough air mass moving within keep inflow steady low rpm reason todays RC engines idle much reliably yesteryear total inlet passage length greater theres venturi customizing story Theres also mysterious inlet stall phenomenon Probably first notice ill effects inlet stall ducted-fan fliers branch aeromodeling new experimenters found contour ducts entry much effect airflow through its cross-sectional area Sharpedged duct entries stole power fans especially airplane turning meeting angle air flying Fan fliers soon discovered smoothly radiused bellmouth duct entries boosted airflow raised efficiency eliminated much sensitivity sideward airflow Perhaps best way explaining action involved compare crowd people tossing Ping-Pong balls rapidly possible bottomless coffee can floor Balls go can fall through hole underneath miss nothing obby Line Model Airplanes Helicopters Boats Cars JAGUAR 4OARF Wing Span 48 Length 40 Weight 48 lbs- 57 lbs Item 865B ~33Oi9S PIPER CUB J-3/ARC 25-36 ALL WOOD CONST SAIE 5p1EWing Span 54 Length 36$5g9 qA95Weight 3 SIbs Iteme8S7-N PIPER CUB J-3/ARF 40 YELLOW/ ALL WOOD CONST Wing Span 67 Length 43 Weight 79 lbs Item#867 FIRE FLY ARF 10-15 20 GLOW INTHE DARK AFTER SUNSET 5plE Wing Span 48 Length 347 Weight 2 2 lbs 2 4 lbs Item #940 SKY BABY-S/ ARF 25-35 20 TRAINER 5M.E Wing Span 51 5 Length 36 Weight 3 3 lbs ltem#852 DEALERS AND DISTRIBUTORS INDUIRIES WELCOME QRDERLANLY 1-300-2494544 u TECH INFORMATION 1-201460-0544 OUR FAX LINE 1-2014604770 WE ACCEPT VISA EASTER CARD & DiSCOVER CARDS PRICES SUBJECT TO CHANGE WITHOUT NOTICE STORE HOURS MONDAY THRU THURSDAY 10AM TO 7 PM FRIDAY 10AM TO 9PM SATURDAYS lOAM TO 4PM PACKAGING AND SHIPPING Ftt 65 50 NEW JERStY RtSIDENTS ADD 6 SALES TAX _ US HOBBY INC 200 MOONACHIE AVE MOONACHIE NJ 07074 US HOBBY INC F7F Tigercat Wingspan inches Wing area807 sqinches Engines45-75 161-91 4 stroke Weight12-l4Ibs Radio 4 6 channel Kit Includes Fiberglass Fuselage Nacelles Foam Core Wing Stabelizer Clear Vacuum Formed Canopy wood parts complete kit $34999 orking Tomorrows Technology 140 S CamoSeco#415 Thcson AZ 85710 Phone/FAX 520 886-3678 HTTPJ/membersaolcom/jrcustom/indexhtmI /4 Qo 4OL4 SKT aABY-L/ARF 25-35 2C TRAINER SNIE Wing Span 51 5 Lengin 36 Weight 3 3 lbs Item 854 balls strike rim area just inside will bounce they interfere other incoming balls prevent some entering interference becomes worse balls being thrown angle can s axis Most go ricochet randomly can walls other produces near jam-up entry analogy balls represent molecules oxygen nitrogen C02 etc air Although terms inaccurate lets call air molecules bottomless coffee can entry ducted fan outer end model engine air intake jam-up entryway inlet stall Looking problem way its obvious make easy balls air molecules pass through opening opening should trumpet-shaped have gently-rounded edge balls molecules hit wall surfaces way will deflected slightly entry path No obstructive jam-up will clog inflow What happens model airplane engines air inlet has major effect its performance Its power depends optimum fuel-air mixture reaching combustion chamber has pass through intake passage first True some air can enter via subpiston induction Cox Tee Dees use feature subpiston gap narrow remains open exceedingly briefly less half millisecond TD 049 18K rpm much air can sneak engine flicker time know rear-rotary induction used record-setting racing engines eg McCoys Doolings instead far simpler front-rotary valve reason restricting intake diameter often cures erratic engine about getting good midrange settings such trick achieve RC barrel throttles Ill explain pointsand next column Until heres helpful tip Keep plastic bag type used supermarkets produce wrapped around nose of engine-powered models time its being flown simple step can add years engines lifespan light Training Beginner advanced tailored individual long-time modeler full size airplane flight instruc tor will make progress fun easy during week stay beautiful far western North Carolina Write call information RC Flight Training 1635 Setawig Rd Brasstown NC 28902 704-389-8968 GMS2000 proud announce arrival Crown Jewel lineup top quality engines GMS2000 120 2-stroke Light weight attention detail typical GMS engineering 2needle carburetor contribute continued success line already established unsurpassed GMS2000 40 47 2 year warranty excellent service support GMS2000 engines meant used seen sc International PO Box 40116 Indianapolis Indiana 46280 1317-844-1978 http//wwwiquestnetfisc North west Model Distribution 21527 NE 227th Battle Ground WA 98604 1-360687-9452
