Radio Control: Aerobatics

RADIO CONTROL AEROBATICS LAST MONTH briefly touched subject Pattern prop selection promised little propeller theory later date Ive written subject before lot material will familiar veterans out Much information both vintage basic Nonetheless ground bears covering again several reasons First providing new faces old data basic function magazine Second lot old faces judging some questions Im asked still fully equipped blank spot propeller knowledge should propeller device used convert rotational power torque thrust propeller blade rotating wing useful think propeller system producing thrust system composed number variable features chosen designer ultimately customer features blade length determines area swept disc actuator disc blade shape plan view blade Cross-Section airfoil blade pitch set-angle number blades also important feature keep things simple will just consider two-blade systems discussion features brings different set advantages disadvantages table taken together determine props efficiency its designed purpose aviation deals compromise propellers probably outstanding example axiom prop works pulling air front moving greater acceleration rear result accelerated airmass movement force thrust reacts against blades propelling aircraft forward Propeller diameter disc swept area determines much air will available blades work move during rotational period Pitch rotational speed determine much little air mass will accelerated moves through disc Because air mass accelerated rotating blades create low-pressure area front themselves low-pressure area causes air ahead prop accelerate toward disc before prop gets air pulled through rotating disc creating high-pressure area rear Nature loves balance equations extra air hauls itself toward empennage what refer slipstream Most us have seen lowpressure high-pressure slipstream effect graphically demonstrated score sheet paper-towel-to-confetti trick Remember acceleration air through swept disc produces thrust acceleration air begins front before prop arrives given point finished rear roughly half acceleration produced either side velocity stream related pitch rotational speed blades background can start consider question efficiency produce equivalent thrust smalldiameter prop must turn higher rpm accelerate slipstream higher speed larger diameter Diameter controls amount air available prop accelerate have two choices can take large amount air move slowly relatively speaking smaller amount air move quickly fairly low speeds models operate happens larger-diameter propellers aerodynamically 80 Model Aviation winner Chip Hydes new Hydeout waits official flight 1998 Nats Advanced flier John Lees son Robert Portland OR pose Johns new Olympian efficient smaller ones simply effective work air So far aerobatic model aircraft concerned bottom line extract greatest amount thrust fixed amount torque better increase diameter decrease rpm rather reverse Now can talk about pitch blade angle Pitch supposedly amount expressed inches country advanced propeller rotation say supposedly because actual fact doesnt happen true distance always little less because phenomenon called propeller slippage Propeller slippage calculation same complicated matter purposes need aware exists like regard analogous losses incurred automatic transmission automobile isnt exactly truth effect somewhat similar Prop pitch slippery subject other reasons well biggest multiple nonstandardized ways measured Propellers rotate means tip blade always traveling much faster root given rpm Almost model props constant-speed type lower rotational speed near root traditionally offset gradually increasing nominal pitch blade nears hub sometimes referred helical pitch true pitch theory move air efficiently over whole blade length maintaining constant angle attack along blade Unfortunately props different makes vary great deal closely stick helical-pitch concept Additionally prop airfoil cross- sections vary slightly undercambered flat-bottom semisymmetrical variation will often found same prop makes little difficult accurately measure pitch angle back side blade usual method Different manufacturers also measure pitches props varying distances out hub blade different Also available Kestrel 2M Regular $7495Special $64 Kestrel 2M has very popular fantastic flier since its introduction back 1993 customers have requested larger version wonderful flying sailplane Kestrel 100 its larger span higher aspect ratio has greater performance its little brother SD7084 airfoil used increase wings speed range penetration wingloading planform sinkrate L/D fantastic Another breakthrough sailplane NSP FAI heavy hitters Ivan Kristensen L Ron Chidgey Rons Typhoon 2000 wingspan ioo wing area 935 sq weight 46 07 wingloading 65 oz/sq ft Airfoil SD7084/7080 Skill level NOv/NOv Radio standard receiver 2-3 servos 550 mah battery pack Kestrel Regular $14000Special $ 7R75 Wing arP2 718 sti Wingloading 53021 Skill h NSP Northeast Sailplane ucts 8O2-65 16 Kirby Lane Willis ton http//wwwnesailcem Please see Racing Ur Proposal 1 iii [611116 Wi1S 11i 1I Send sase catalog WINDSOR PROPELLER CO 3219 Monier Circle Rancho Cordova CA 95742 ph 9166318385A spots naturally produce different angles No common method used two manufacturers follows above just about magazine prop comparison tests based prop size pretty much waste time trees editorial spaceeven ones compare decibel readings decibel comparisons mean anything prop prop measured thrust must equal Only measure two systems moving same amount air can accurately state quieter other point may want put down beverage begin reading both hands things begin get mildly technical Pitch diameter together determine load Load amount work asking engine Increasing pitch increases load because increases drag Props create induced drag create lift induced drag opposes resists rotational torque lift produced prop blade thrust Blade lift produced perpendicular relative airflow across bladenot perpendicular prop disc As blade inclined pitch angle direction flight lift produces inclined means vector component lift produced actually resists rotation added drag other words prop fighting itself just turn outer one-third prop blade produces thrust As pitch increases blade angle attack increases drag component increases along lift course Remember blade angle constant speed prop increases toward hub Near hub blade angle extreme lift created acts against rotation outer portions prop blade produce thrust simply because rotational speed greater blade angle less extreme both inclined lift vector component blade drag less thereby making lift produced available thrust can trim little 1/4 inch diameter good prop wind up dog barely flies model Adding diameter system gravy Beyond obvious increase load added drag problem torsional stiffness Consider Props lack torsional rigidity flex depitch go flat under load flutter buzz tips extreme cases break flight Flexing depitching mean less efficient transfer horsepower air tip flutter means massive increase noise Given identical construction materials longer prop must thicker must possess proportionally greater mass achieve same torsional rigidity shorter blade cross-section hub eventually becomes large virtually useless added mass also produces increased inertia brings double whammy poor acceleration increased gyroscopic precession As practical consideration too much prop diameter can cause problems ground clearance As always solution compromise Pattern compromise use enough diameter move good amount air enough pitch load engine near peak its particular torque curve Blade tip shape also important Props like wings produce vortices tips air tries flow over high-pressure area lowpressure side vortices represent drag wasted horsepower efficient blade shape therefore produces smallest tip vortex Since prop moves faster tip root blade progressively narrower thinner tip best Rounded tips efficient squared ones 82 Model Aviation ER AIRSCRIIV Stripwood easier & accurate 1/32 increment precision cuts Uses standard type 11 hobby blade Cuts 1/2 wide 1/4 thick Builders favorite $595 suggested retail IIL5&m Rounds smooths cowlings & fuselages Uses heavy-duty cutting blade Micro-adjustable cutting depth Shape edges & thins strips Great companion tool Balsa Stripper $595 suggested retail JKEN Er4JK & Marine Engines Rebuilt Repaired Updated K&B can make engine like new again need send us K&B engine will repaired original parts Labor charge $7 50 $20 00 520-4533579 2100 College Drive Lake Havosu City AZ 86403 NOi Some engine mop nol senoceoble dine age orcand please caii before sending engine angled raked tips seem little efficient round ones Tip shape area efficiency relates directly sound prop noise produced tips Less vortex production seems equal less noise Lower tip speed definitely equals less noise tied diameter diameter faster prop tips move given rpm another important limiting factor regarding diameter high-aspect-ratio wing long narrow aerodynamically efficient low-aspect-ratio wing short broad same true props Increasing blade width increases drag faster increases thrust Wide props increase aerodynamic braking effect down lines though much little diameter may sometimes little stiffer just because added blade material Most commercially successful propeller blade airfoils pretty ordinary vanillabean stuff RC model aircraft propellers operate over wide speed range lot cross-flow going Given conditions manufacturers seem have decided exotic sections little use So what Pattern bottom line considering current constant-speed flying styles currently available hardware preference long rigid light relatively narrow props must choose among features opt long stiff narrow light order Use sufficient diameter move air means hare minimum 15 inches 120 YS 140 can easily turn 155 16-inch prop new large two-strokes comfortable up 17 inches Increase pitch point engine rpm load-limited just below torque peak will keep prop tip speed down reasonable level sound reduction NEW LASER PLAN PACS Dont pay big bucks wwt kits top quality plans laser Lut parts available43 Scale 84 Span FokDV]] Plans $2500 FG cowl $2500 Laser cut parts $6500 80 Spanill Laser cut parts $7500 1/4 Scale__ tcIIFak F-lit Plans $2500 Laser cut parts $7500 ALBATROSDVA Plans $3600 Laser ports $7500 1/6th Scale PLANS $2600 Laser cur parts $6500 1/4 Scale 80 Span Monv Laser Poor ore orOrlobie ~PLANS 13500 Laser parts $15000 SHIPPING AD $500 TO PLANS ORDER $800 TO LASER PAC BEST IN SCALE CATALOG $700 POST PAID BOB HOLMAN PLANS PO BOX 741 SAN BERNARDINO CA 92402 909 885 3959 FAX 909 889 9307 THE US SAILPLANE & ELECTRIC AIRPLANE MAGAZINE Scale & Sport Electrtcs Demystsfysng Electrscs Asrfosisr Build Square Plan Features Scale Slope Thermal Soaring Center Poster Special Features much Over three I S&E Modeler PO Box 4250 W Richiand WA 99353 RADIO SOUTH INC January1999 83 PRECISION FIBER GS Hundreds cowls radial cowls & wheelpants Strong lightweight one-piece construction Exact duplicate manufacturers original Phone orders information call 423-984-0828Send $100 catalog $200 Outside US 9am -6 pm EDT~ 3745 Fox Creek Rd sville TN 37777 PRO-DRIVER Contains 4 1300 mah battery cells senses plug fouled & boosts power LED bar garaph meter display plug condition Supports Futaba J charge Sale Price $5300Sp DRIVER MARK II7 auto shut down ISale Price $5800 PRO-HINGES 3702 N Pace Pensacola FL 32505___for use cyanocrylate adhesives RC $2 49/pkg 18 1/4 Scale $279/pkg 24 Toll Free Order Line Orders Only Please8009627802It available local hobby shop order Repair formation -434-0909 visit webs ite http//www wtpnet/DBEST/radosouth/RSI htmldirect DEALER INQUIRIES INVITED UejU E-Z BILT WWII Pedal Planes will have much fun building 3-6 year old will have flying Kit includes full size patterns complete instructions color photo list ready made parts included Kits $2000 total Specify plan wanted Kits available P-38 P-Si Brochure $100 SASE Flight Line Toys ox 3484 Springfield MO 65808 ModelAB4EnginePriCe Length sicLenSIgleeSiee OF 300 4311620-40$1469 OF 350 351 6 43116 469 9F 400 1 31311640-60$1469 OF 450 431lIP 4311640 60$1499 OF 500 2 4311660 9051636 OF 51055/3243131713260-1291875 OF 610651324 316713260-12$1960 OF 710T5/3243167/3260- 1291960 OF 36J310651324307/3240- 12$1699 6F57J SloT 532431623240- 12$2039 6F770 3bPS 31164 1l21l4Gas$2557 oooo tL ~ P00004 common Pattern engines 11-13 pitches hit mark As rule thumb narrower blade higher pitch can used current APC 15 x 12 15 x 13N l20s 155 x 13N 16 x 13N 1 40s offerings very popular excellent choices YS tine engines APC 17 x 12N good choice two-stroke 120/140 engines Pattern work advice would avoid larger-diameter lower-pitch wide-blade setups Ive seen used such 16 x 8-10 17 x 10 noisier less efficient much several ounces heavier Multiblade three- four-blade props becoming trendy again would avoid well inherently less efficient because additional blades operate more- disturbed air problem compounded model use because relatively high rotational speeds scale effect airplanes props smaller air molecules fullscale None excuse avoiding own homework experimentation because model/engine/pilot/operating environment combination different Use theory offered get started right direction points remember use enough diameter move air efficiently enough pitch load engine properly Keep tip speed down reduce noise Prop-comparison tests have lately fallen out fashion modeling media should run across can now read enough background understand what isnt telling 4Aviation Veritage Airplane CO-ROMs high quality Aviation Heritage Airplane CD-ROM contains Send $2495 * 300-450 Photos * Details $450 s/h per order * Scale Drawings * Planes & VariantsAviation Heritage Titles Available Now ox 665 Grumman Aircraft #CO-5Destin FL 32540 DUCK GDDaE GULFHAWK WILDCAT WIDGEON & MORE 1-800-999-0141 Grumman Aircraft #CD-6 C~An Asgto HELLCAT Tk3AT 6EAAT ALBATSS T INTRUDuP M-sK WWII Fighters #co-7WWII Bombers #CD 9Douglas #cD-13 Fighters &Attack1945C75 sos Bombers &Support Al45-75gtcINo Vought #co-s Cessna #CD-I IDouglas #CD12X-Planes #co- Paul Matt Scale Drawings & Photos 124 Type Airplanes sco- thra 8C0-4 Paul Matt Scale Drawings available 4 CD-ROMs photos & drawings Let us know want notified upon release au OF VIEWING Coming 1999LockheedBell-T-IiSNJOS OF R-UITOS Early JetsNorth AmericanRepublic- GRE TAIOPA3 TOS WWICurtissNorthrop- ORIGINAL PHOTOS FACTORY PHOTOS Air RacingConsolidatedFlying Wing- HISTORIC PHOTOS BoeingMartinUnusual Aircraft- 1 -OF-KIND PHOTOS AMAZING PHOTOS .sorely needed extreme high quality ~aesuou r-cnns - David Fogarty AMA #9818- BEAUTIFUL PHOTOS Scale Model Aircraft Designer/BuilderFree Catalog 84 Model Aviation ror nose gear solution Need 12 K Castor, Struts Also Availahie Doect add $300 S&H USA 1-800-905-3632 Fax 217-351-3590 Fults Tooling PO Box 155 Savoy IL 61874 MICRO DIGITAL MOTOR CONTROLLERS SAFE NO GLITCH POVER ON SOFT LOV TORQUE START UP NIGH RATE SMALL SIZE LIGHT VEIGHT SELF ALIGNS TO YOUR TRANSMITTER NO ADJUSTMENT NECESSARY MICRO DEMON 100 2OAMP 1-14CEU. 12x085x039 13g/46oz wires 4700Hz includes setup LED 995 *NSI* MICRO DEMON 102 *NSIeJ* 20AMP 6-8cELL BEC BRAKE 21g175oz wires 4700Hz 18x085x039 includes setup LED$5995 SPEED DEMON 200 35AMP 1-1 6CELL 16 xl 0 xO42 26g192oz wires 2400Hz.$8295 VIPER MODEL PRODUCTS 3475 Edison isy Suite Menlo Park CA 94025 1-800-5928473 VISA MASTERCARD

RADIO CONTROL AEROBATICS LAST MONTH briefly touched subject Pattern prop selection promised little propeller theory later date Ive written subject before lot material will familiar veterans out Much information both vintage basic Nonetheless ground bears covering again several reasons First providing new faces old data basic function magazine Second lot old faces judging some questions Im asked still fully equipped blank spot propeller knowledge should propeller device used convert rotational power torque thrust propeller blade rotating wing useful think propeller system producing thrust system composed number variable features chosen designer ultimately customer features blade length determines area swept disc actuator disc blade shape plan view blade Cross-Section airfoil blade pitch set-angle number blades also important feature keep things simple will just consider two-blade systems discussion features brings different set advantages disadvantages table taken together determine props efficiency its designed purpose aviation deals compromise propellers probably outstanding example axiom prop works pulling air front moving greater acceleration rear result accelerated airmass movement force thrust reacts against blades propelling aircraft forward Propeller diameter disc swept area determines much air will available blades work move during rotational period Pitch rotational speed determine much little air mass will accelerated moves through disc Because air mass accelerated rotating blades create low-pressure area front themselves low-pressure area causes air ahead prop accelerate toward disc before prop gets air pulled through rotating disc creating high-pressure area rear Nature loves balance equations extra air hauls itself toward empennage what refer slipstream Most us have seen lowpressure high-pressure slipstream effect graphically demonstrated score sheet paper-towel-to-confetti trick Remember acceleration air through swept disc produces thrust acceleration air begins front before prop arrives given point finished rear roughly half acceleration produced either side velocity stream related pitch rotational speed blades background can start consider question efficiency produce equivalent thrust smalldiameter prop must turn higher rpm accelerate slipstream higher speed larger diameter Diameter controls amount air available prop accelerate have two choices can take large amount air move slowly relatively speaking smaller amount air move quickly fairly low speeds models operate happens larger-diameter propellers aerodynamically 80 Model Aviation winner Chip Hydes new Hydeout waits official flight 1998 Nats Advanced flier John Lees son Robert Portland OR pose Johns new Olympian efficient smaller ones simply effective work air So far aerobatic model aircraft concerned bottom line extract greatest amount thrust fixed amount torque better increase diameter decrease rpm rather reverse Now can talk about pitch blade angle Pitch supposedly amount expressed inches country advanced propeller rotation say supposedly because actual fact doesnt happen true distance always little less because phenomenon called propeller slippage Propeller slippage calculation same complicated matter purposes need aware exists like regard analogous losses incurred automatic transmission automobile isnt exactly truth effect somewhat similar Prop pitch slippery subject other reasons well biggest multiple nonstandardized ways measured Propellers rotate means tip blade always traveling much faster root given rpm Almost model props constant-speed type lower rotational speed near root traditionally offset gradually increasing nominal pitch blade nears hub sometimes referred helical pitch true pitch theory move air efficiently over whole blade length maintaining constant angle attack along blade Unfortunately props different makes vary great deal closely stick helical-pitch concept Additionally prop airfoil cross- sections vary slightly undercambered flat-bottom semisymmetrical variation will often found same prop makes little difficult accurately measure pitch angle back side blade usual method Different manufacturers also measure pitches props varying distances out hub blade different Also available Kestrel 2M Regular $7495Special $64 Kestrel 2M has very popular fantastic flier since its introduction back 1993 customers have requested larger version wonderful flying sailplane Kestrel 100 its larger span higher aspect ratio has greater performance its little brother SD7084 airfoil used increase wings speed range penetration wingloading planform sinkrate L/D fantastic Another breakthrough sailplane NSP FAI heavy hitters Ivan Kristensen L Ron Chidgey Rons Typhoon 2000 wingspan ioo wing area 935 sq weight 46 07 wingloading 65 oz/sq ft Airfoil SD7084/7080 Skill level NOv/NOv Radio standard receiver 2-3 servos 550 mah battery pack Kestrel Regular $14000Special $ 7R75 Wing arP2 718 sti Wingloading 53021 Skill h NSP Northeast Sailplane ucts 8O2-65 16 Kirby Lane Willis ton http//wwwnesailcem Please see Racing Ur Proposal 1 iii [611116 Wi1S 11i 1I Send sase catalog WINDSOR PROPELLER CO 3219 Monier Circle Rancho Cordova CA 95742 ph 9166318385A spots naturally produce different angles No common method used two manufacturers follows above just about magazine prop comparison tests based prop size pretty much waste time trees editorial spaceeven ones compare decibel readings decibel comparisons mean anything prop prop measured thrust must equal Only measure two systems moving same amount air can accurately state quieter other point may want put down beverage begin reading both hands things begin get mildly technical Pitch diameter together determine load Load amount work asking engine Increasing pitch increases load because increases drag Props create induced drag create lift induced drag opposes resists rotational torque lift produced prop blade thrust Blade lift produced perpendicular relative airflow across bladenot perpendicular prop disc As blade inclined pitch angle direction flight lift produces inclined means vector component lift produced actually resists rotation added drag other words prop fighting itself just turn outer one-third prop blade produces thrust As pitch increases blade angle attack increases drag component increases along lift course Remember blade angle constant speed prop increases toward hub Near hub blade angle extreme lift created acts against rotation outer portions prop blade produce thrust simply because rotational speed greater blade angle less extreme both inclined lift vector component blade drag less thereby making lift produced available thrust can trim little 1/4 inch diameter good prop wind up dog barely flies model Adding diameter system gravy Beyond obvious increase load added drag problem torsional stiffness Consider Props lack torsional rigidity flex depitch go flat under load flutter buzz tips extreme cases break flight Flexing depitching mean less efficient transfer horsepower air tip flutter means massive increase noise Given identical construction materials longer prop must thicker must possess proportionally greater mass achieve same torsional rigidity shorter blade cross-section hub eventually becomes large virtually useless added mass also produces increased inertia brings double whammy poor acceleration increased gyroscopic precession As practical consideration too much prop diameter can cause problems ground clearance As always solution compromise Pattern compromise use enough diameter move good amount air enough pitch load engine near peak its particular torque curve Blade tip shape also important Props like wings produce vortices tips air tries flow over high-pressure area lowpressure side vortices represent drag wasted horsepower efficient blade shape therefore produces smallest tip vortex Since prop moves faster tip root blade progressively narrower thinner tip best Rounded tips efficient squared ones 82 Model Aviation ER AIRSCRIIV Stripwood easier & accurate 1/32 increment precision cuts Uses standard type 11 hobby blade Cuts 1/2 wide 1/4 thick Builders favorite $595 suggested retail IIL5&m Rounds smooths cowlings & fuselages Uses heavy-duty cutting blade Micro-adjustable cutting depth Shape edges & thins strips Great companion tool Balsa Stripper $595 suggested retail JKEN Er4JK & Marine Engines Rebuilt Repaired Updated K&B can make engine like new again need send us K&B engine will repaired original parts Labor charge $7 50 $20 00 520-4533579 2100 College Drive Lake Havosu City AZ 86403 NOi Some engine mop nol senoceoble dine age orcand please caii before sending engine angled raked tips seem little efficient round ones Tip shape area efficiency relates directly sound prop noise produced tips Less vortex production seems equal less noise Lower tip speed definitely equals less noise tied diameter diameter faster prop tips move given rpm another important limiting factor regarding diameter high-aspect-ratio wing long narrow aerodynamically efficient low-aspect-ratio wing short broad same true props Increasing blade width increases drag faster increases thrust Wide props increase aerodynamic braking effect down lines though much little diameter may sometimes little stiffer just because added blade material Most commercially successful propeller blade airfoils pretty ordinary vanillabean stuff RC model aircraft propellers operate over wide speed range lot cross-flow going Given conditions manufacturers seem have decided exotic sections little use So what Pattern bottom line considering current constant-speed flying styles currently available hardware preference long rigid light relatively narrow props must choose among features opt long stiff narrow light order Use sufficient diameter move air means hare minimum 15 inches 120 YS 140 can easily turn 155 16-inch prop new large two-strokes comfortable up 17 inches Increase pitch point engine rpm load-limited just below torque peak will keep prop tip speed down reasonable level sound reduction NEW LASER PLAN PACS Dont pay big bucks wwt kits top quality plans laser Lut parts available43 Scale 84 Span FokDV]] Plans $2500 FG cowl $2500 Laser cut parts $6500 80 Spanill Laser cut parts $7500 1/4 Scale__ tcIIFak F-lit Plans $2500 Laser cut parts $7500 ALBATROSDVA Plans $3600 Laser ports $7500 1/6th Scale PLANS $2600 Laser cur parts $6500 1/4 Scale 80 Span Monv Laser Poor ore orOrlobie ~PLANS 13500 Laser parts $15000 SHIPPING AD $500 TO PLANS ORDER $800 TO LASER PAC BEST IN SCALE CATALOG $700 POST PAID BOB HOLMAN PLANS PO BOX 741 SAN BERNARDINO CA 92402 909 885 3959 FAX 909 889 9307 THE US SAILPLANE & ELECTRIC AIRPLANE MAGAZINE Scale & Sport Electrtcs Demystsfysng Electrscs Asrfosisr Build Square Plan Features Scale Slope Thermal Soaring Center Poster Special Features much Over three I S&E Modeler PO Box 4250 W Richiand WA 99353 RADIO SOUTH INC January1999 83 PRECISION FIBER GS Hundreds cowls radial cowls & wheelpants Strong lightweight one-piece construction Exact duplicate manufacturers original Phone orders information call 423-984-0828Send $100 catalog $200 Outside US 9am -6 pm EDT~ 3745 Fox Creek Rd sville TN 37777 PRO-DRIVER Contains 4 1300 mah battery cells senses plug fouled & boosts power LED bar garaph meter display plug condition Supports Futaba J charge Sale Price $5300Sp DRIVER MARK II7 auto shut down ISale Price $5800 PRO-HINGES 3702 N Pace Pensacola FL 32505___for use cyanocrylate adhesives RC $2 49/pkg 18 1/4 Scale $279/pkg 24 Toll Free Order Line Orders Only Please8009627802It available local hobby shop order Repair formation -434-0909 visit webs ite http//www wtpnet/DBEST/radosouth/RSI htmldirect DEALER INQUIRIES INVITED UejU E-Z BILT WWII Pedal Planes will have much fun building 3-6 year old will have flying Kit includes full size patterns complete instructions color photo list ready made parts included Kits $2000 total Specify plan wanted Kits available P-38 P-Si Brochure $100 SASE Flight Line Toys ox 3484 Springfield MO 65808 ModelAB4EnginePriCe Length sicLenSIgleeSiee OF 300 4311620-40$1469 OF 350 351 6 43116 469 9F 400 1 31311640-60$1469 OF 450 431lIP 4311640 60$1499 OF 500 2 4311660 9051636 OF 51055/3243131713260-1291875 OF 610651324 316713260-12$1960 OF 710T5/3243167/3260- 1291960 OF 36J310651324307/3240- 12$1699 6F57J SloT 532431623240- 12$2039 6F770 3bPS 31164 1l21l4Gas$2557 oooo tL ~ P00004 common Pattern engines 11-13 pitches hit mark As rule thumb narrower blade higher pitch can used current APC 15 x 12 15 x 13N l20s 155 x 13N 16 x 13N 1 40s offerings very popular excellent choices YS tine engines APC 17 x 12N good choice two-stroke 120/140 engines Pattern work advice would avoid larger-diameter lower-pitch wide-blade setups Ive seen used such 16 x 8-10 17 x 10 noisier less efficient much several ounces heavier Multiblade three- four-blade props becoming trendy again would avoid well inherently less efficient because additional blades operate more- disturbed air problem compounded model use because relatively high rotational speeds scale effect airplanes props smaller air molecules fullscale None excuse avoiding own homework experimentation because model/engine/pilot/operating environment combination different Use theory offered get started right direction points remember use enough diameter move air efficiently enough pitch load engine properly Keep tip speed down reduce noise Prop-comparison tests have lately fallen out fashion modeling media should run across can now read enough background understand what isnt telling 4Aviation Veritage Airplane CO-ROMs high quality Aviation Heritage Airplane CD-ROM contains Send $2495 * 300-450 Photos * Details $450 s/h per order * Scale Drawings * Planes & VariantsAviation Heritage Titles Available Now ox 665 Grumman Aircraft #CO-5Destin FL 32540 DUCK GDDaE GULFHAWK WILDCAT WIDGEON & MORE 1-800-999-0141 Grumman Aircraft #CD-6 C~An Asgto HELLCAT Tk3AT 6EAAT ALBATSS T INTRUDuP M-sK WWII Fighters #co-7WWII Bombers #CD 9Douglas #cD-13 Fighters &Attack1945C75 sos Bombers &Support Al45-75gtcINo Vought #co-s Cessna #CD-I IDouglas #CD12X-Planes #co- Paul Matt Scale Drawings & Photos 124 Type Airplanes sco- thra 8C0-4 Paul Matt Scale Drawings available 4 CD-ROMs photos & drawings Let us know want notified upon release au OF VIEWING Coming 1999LockheedBell-T-IiSNJOS OF R-UITOS Early JetsNorth AmericanRepublic- GRE TAIOPA3 TOS WWICurtissNorthrop- ORIGINAL PHOTOS FACTORY PHOTOS Air RacingConsolidatedFlying Wing- HISTORIC PHOTOS BoeingMartinUnusual Aircraft- 1 -OF-KIND PHOTOS AMAZING PHOTOS .sorely needed extreme high quality ~aesuou r-cnns - David Fogarty AMA #9818- BEAUTIFUL PHOTOS Scale Model Aircraft Designer/BuilderFree Catalog 84 Model Aviation ror nose gear solution Need 12 K Castor, Struts Also Availahie Doect add $300 S&H USA 1-800-905-3632 Fax 217-351-3590 Fults Tooling PO Box 155 Savoy IL 61874 MICRO DIGITAL MOTOR CONTROLLERS SAFE NO GLITCH POVER ON SOFT LOV TORQUE START UP NIGH RATE SMALL SIZE LIGHT VEIGHT SELF ALIGNS TO YOUR TRANSMITTER NO ADJUSTMENT NECESSARY MICRO DEMON 100 2OAMP 1-14CEU. 12x085x039 13g/46oz wires 4700Hz includes setup LED 995 *NSI* MICRO DEMON 102 *NSIeJ* 20AMP 6-8cELL BEC BRAKE 21g175oz wires 4700Hz 18x085x039 includes setup LED$5995 SPEED DEMON 200 35AMP 1-1 6CELL 16 xl 0 xO42 26g192oz wires 2400Hz.$8295 VIPER MODEL PRODUCTS 3475 Edison isy Suite Menlo Park CA 94025 1-800-5928473 VISA MASTERCARD