Radio Control Giant Scale Bob Beckman THOSE TERRIBLE TWOS Most mod elers fascinated twin-engined air craft. know am multi-engine models have reputation being diffi cult difficult build difficult fly difficult keep crashing Hence months title few years ago spectator series events seemed prove having two engines can terrible happened time span less two months spread out California New York started Clearlake California Dick Hersheys quarter-scale Grumman Goose ready its first flight wife Sacramento visit include fly-in Merwin Ranch Lee Taylor heard town told Gooses first flight scheduled next day Thursday too good miss Evelyn scrapped original plans rest week made three-hour drive Clearlake early next morning arrived just Dick crew getting big bird ready Goose launched crew two us tagging along boarded flat-decked pontoon boat headed out lake Lee Taylor test pilot made several high-speed taxi runs feel bird out reported aircraft felt tail heavy headed shore make some changes total six pounds lead placed far forward possible added before Lee felt comfortable balance headed out lake again found wind shifted Up now takeoff runs out lake now would have made toward shoreline meant moving farther out leave plenty space between plane spectators houses shore time takeoff run picture perfect big amphibian lifted off climbed out just like real thing Lee made shallow climbing 1800 turn head back out lake leveled off about 100 feet no warning tail suddenly dropped plane flipped onto its back rolling dropped straight lake video tapes made flight have post mortems Ill tell some conclu sions later Two days after Merwin Ranch Eagle Squadrons fabulous fly-ins Phil Kara filis planning have twinQuadra-powered Douglas A-20 its malden flight Since plane flown before could participate normal activity Phil planned fly evening after regular flying completed turned out peoDle wanted see theres fasci nation twins again Event Director agreed let Phil fly during noon break Phil fired up engines taxied out flight line smoothly fed full throttle aircraft accelerated rolling straight string rotated lifted off started climbing out Suddenly port engine sputtered died plane rolled left plunged ground Agaln Ill leave postmortem later took place May Cali fornia July Olean NY STARS Rally Don Godfrey complet ed test flown B-25 first earlier year scheduled fly Rally got some great takeoff shots moved over near Don made pass over field happy way plane responding control inputs nounced going land As turning onto final big twin re fused respond Up elevator signals plowed ground off end runway walked end field saw pieces spread far 100 feet impact point As stood looking saddest sights modeling realized Bob Campbell getting ready fly Grumman Tigercat way down other end field started back hoping get time takeoff As trudged length field its long thought about recent experiences twins Could jinx vowed Bobs Tigercat crashed taking pictures would never point camera another twin-engined model rest life 54 Model Aviation Dick Hersheys 13-ft-span Grumman Goose about lift Californias Clearlake Its Ill-fated first flight Phil Karafilis Douglas A-20 Merwin Ranch purr its twin Quadras big part fascination twins As ship climbs out after takeoff R Phil didnt know yet left engine already saggingabout quit abruptly look closeiy can see beginning feed right aileron rudderbut too late Readers should reminded twin-engine Giant Scale planes shown probably weigh excess 55-lb limit AMA model aircraft hence would covered AMAl ia bility Insurance case accident Don Godfreys first 5-25 lifts off STARS Rally what turned out its last flight Bob thought camera might jinx twins Phil Karaf ills magnificent Beech D-18 earlier pictures January 1986 Issue detractions realism engines spark plugs hightenslon leads protruding below cowls After about dozen flights too bit dust Its several years later now Bobs Tigercat still going strong fact Bob has become prolific successful builder large multi-engined models know As working column got note him picture latest effort still under construction Theres another sad chapter story unfortunately California 1984 IMAA Fun Fly chance see Phil Karafilis beautiful Beech D-18 already made about 10 flights Phil made two flights day clicked away madly finally fill picture-taking just relaxed watching Phil put bird through its paces made pass down field pulled up split-S somewhat nonscale maneuver suspect plane nev er stopped rolling however corkscrewed right ground least time didnt have camera pointed Well whats point war stories Am trying say multiengine models impractical Certainly Bob Campbell others have shown successful can morbid fascination crashes No dont like next modeler better learn what can times think magazines us write try ignore aspect hobby Its fact life people tend learn failure successbut ex amine failure ask So what Whys four horror stories Its always possible 100% certain cause aircraft crashes models full-scale some conclusions have reached cases best knowledge heres what happened Grumman Goose built information derived primarily photographs full-scale aircraft Very little detailed data available retrospect appears incidence built wing excessive fact understand after fact Dick shey received letter engineer worked original Goose indicated prototype same problem remains Dicks Goose being rebuilt another model er Im hoping hear suc cessful maiden flight soon Godfreys B-25 apparently vic tim inadequate structural strength tail surfaces stabilizer spar elevator hinges failed withstand flight loads possible control surface flutter crash Karafilis D-18 due battery failure Note above failures due way fact two engines plane Ive saved A-20 last because its demise due fact two engines quit unbalanced thrust threw plane out control did engine quit turned out flexible tubing fuel pickup inside port fuel tank come off brass tube feed-through cap As long plane sitting level engine could draw almost half fuel tank However nose-high attitude climbout after takeoff engine starved fuel port engine dead flight controls could overcome full-throttle thrust starboard engine time Phil real ized engine out too late same fuel tank problem singleengine model would have awkward would likely have resulted crashContinued page 139 ROUSH KITS USA Super Kwick Fil Span 70 Area 927 Power 75 12 Two Ugly Stick Span 70 Area 1290 Power 75 12 $9995 Kitten Span 45 Area 290 Power 15 19 $3495 EAA Acro ii Span 60 Area 1300 Power 75 1 8 19~ Introductory Price Direct Sales Only Send $100 Catalog ROUSH MFG 1728 Bywood St SE Canton OH 44707 216 484-6810 4 April 1986 55 Bob Campbell has almost finished latest long line extremely large multi-eng miniature aircraft quarterscale 1 3ft.span P38 Power will two 52 Cu Sache-Doimer engines CA MASK CA glue works wonders building models right Unfortunately gives off enough fumes knock vulture off carcass modelers have suffered medical problems after inhaling CA fumes take chances special vapor respirator filters CA fumeal soft face mask adjustable st raps comfortably fits face sizes easy breathing valve allows prolonged use providing dependable filtering concentrations up 1000 PPMl though rugged industrial mask light weight elimi nate fatigue Dont get gassed CA Get protected Order CA Mask today Just $1247 shipping cheaper hospital visit Money order Master Charge Visa include expiration date check allow 20 days clear Sorry no CODs Pelican Enterprises Inc 265 OXFORD LANE BLOOMINGDALE ILLINOIS 60108 P S Send catalog modelers safety supplies Yes Im sick CA fumes Send CA mask Enclosed $1247 shipping NAME ADDRESS_______________________ CITY STATE____________ ZIP____________ Li VISA Li MASTER Exp Date________ FOX GLOW PLUGS FOR THOSE WHO WANT THE BEST SHORT $119 toim J$119 AC SNORT $169 Si Rhodium twice expensive platinum s better glow plugs space age insulator costs glass crack use Job shops couldnt hold tolerances wanted metal partsso make ourselves though less 1 plug 500 fails glow FOX PLUGS THOSE WHO WANT THE BEST Visa MasterCard accepted F 0 CO 5306 TOWSON AVE FORT SMITH ARK 72901 15011 646 1656 RC Old-Timers/Mathews Continued page 53 non-SAM-era models Hal deBolt tells will soon start column early RC designs Model Airplane News Id like some material Free Flight same approximate time frame am particularly turned PAA-Load both large small designs wartime goodies such Kid etc some really attractive sport-types such Pacificoaster last column Any photos would greatly appreciated Naturally puts would helpful well Two examples sort thing thinking Veco Sioux Bill Winters Midwest Sniffer enlargements published Flying Models few years back could get excited about sort conceptor impor tant youve tried itwould please drop line Dee B Mathews 8420 Nantucket Wichita KS 67212 RC Giant Scale/Beckman Continued page 55 Conclusion least conclusion Twins multi-engined models dont have considered terrible course theyre going compli cated turns out fail its pretty much same reasons models fall moral story learn failures apply lessons new project Pretty soon failures get few far between Bob Beckman 8248 Holly Grove Ct Manassas VA 22110 RC Pylon Racing/Hager Continued page 56 valve train reaches point valves dont follow bump cam may hit piston 14 x 10 prop its resulting rpm combination will keep well away since engines will run mid 8OOOs ground 10000 air diving three approved engines have redlines well past 12000 rpm Since racing need speed get pitch has increase because four-stroke engines now roughly 10000 rpm saw 15000 two-stroke 60 air Assuming 100 mph before seven-in pitch 15000 rpm now need 10 inches pitch 10000 rpm same speed 7 x 15000 approximately equals 10 x 10000 An added bonus larger prop efficient smaller thrust consistent rpm doesnt fall off turn since four-stroke lugs better meaning doesnt slow down much same ap plies takeoff climbing giving forgiving flight envelope can begin realize what have heard before propeller matching plane engine very important Back power torque Horsepower always combination torque rpm HP UE x RPM x k Torque twisting ability engine crankshaft have lugger always occurs lower rpm horsepow er peak 12 bigger engine has torque 60 half its size 12 generates torque much lower rpm Thats 12 11000 rpm 60 17000 rpm can both rated 16 horsepower just develop different set conditions Two-strokes have become powerhouses because easy increase rpm Look characteristics three engines see HP developed 12 cubic inch four-stroke 60 cubic inch two-stroke 45 cubic inch twostroke ducted fan engine deliver ap proximately 16 HP graph front column RH Torque climbs drops off approximately 2A HP max imum HP keeps climbing after torque drops because rpm still climbing torque drops faster rpm climbs HP starts drop hot engine sharper peaks types engines dif ficult set useful certain props Typically l2s use 13/15-inch prop 60s 11-inch 45s 5/9 inches 45s can actually develop HP cant use because dont have torque turn bigger props need larger prop higher-speed engine wont let engine get its horsepower peak doesnt matter horses liter ature says its rated Look curves 12 closely graph front column BH An engine doesnt develop HP automatically smaller prop just lets get up torque curve closer HP peak raised peak hotter engine may have shifted lower torque-curve anyway Horsepower Hop-up As long compare engines using same prop extra horsepower simple sounds since rpm wont go up itself unless changes made engine hop-up. engine de signed differently torque must creased some other way since rpm must go up takes torque easiest way power let rev. smaller prop less pitchbut allowed fore back torque increase THE LEADER IN COM PETITION NEW i 4 CYCLE THP DESIGN PRICE f 299 379 14479 15689 16989 NEW F 4 j NEW HIGH TECH AIRFOIL SECTION lOTO 20% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUEL PROOF HIGH LUSTER FINISH DIAPITCHPRICE 534149 634149 72833456179 833/,4568189 845667199 9456677199 104S667209 106W8W209 106EW219 ii46777/,7I,8229 115W229 11SEW239 1167239 124W279 125W279 1256279 1356349 1456459 1556659 164VzN989 16678969 PROPELLERS April1986 139 TAILORED HELICAL PITCH DEVELOPED TO GIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALL THE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW PITCH THP 86 77 8 877 8 677 8 67 678 PRO SERIES 3 RC PYLON RACING SERIES 500 DIA PITCH PRICE 7SN 5/N279 8I 6/,7/z78 299 SERIES 400C 8 66777 289 9777/289 W WIDE BLADE EW EXTRA WIDE N NARROW
Edition: Model Aviation - 1986/04
Page Numbers: 54, 55, 139
Radio Control Giant Scale Bob Beckman THOSE TERRIBLE TWOS Most mod elers fascinated twin-engined air craft. know am multi-engine models have reputation being diffi cult difficult build difficult fly difficult keep crashing Hence months title few years ago spectator series events seemed prove having two engines can terrible happened time span less two months spread out California New York started Clearlake California Dick Hersheys quarter-scale Grumman Goose ready its first flight wife Sacramento visit include fly-in Merwin Ranch Lee Taylor heard town told Gooses first flight scheduled next day Thursday too good miss Evelyn scrapped original plans rest week made three-hour drive Clearlake early next morning arrived just Dick crew getting big bird ready Goose launched crew two us tagging along boarded flat-decked pontoon boat headed out lake Lee Taylor test pilot made several high-speed taxi runs feel bird out reported aircraft felt tail heavy headed shore make some changes total six pounds lead placed far forward possible added before Lee felt comfortable balance headed out lake again found wind shifted Up now takeoff runs out lake now would have made toward shoreline meant moving farther out leave plenty space between plane spectators houses shore time takeoff run picture perfect big amphibian lifted off climbed out just like real thing Lee made shallow climbing 1800 turn head back out lake leveled off about 100 feet no warning tail suddenly dropped plane flipped onto its back rolling dropped straight lake video tapes made flight have post mortems Ill tell some conclu sions later Two days after Merwin Ranch Eagle Squadrons fabulous fly-ins Phil Kara filis planning have twinQuadra-powered Douglas A-20 its malden flight Since plane flown before could participate normal activity Phil planned fly evening after regular flying completed turned out peoDle wanted see theres fasci nation twins again Event Director agreed let Phil fly during noon break Phil fired up engines taxied out flight line smoothly fed full throttle aircraft accelerated rolling straight string rotated lifted off started climbing out Suddenly port engine sputtered died plane rolled left plunged ground Agaln Ill leave postmortem later took place May Cali fornia July Olean NY STARS Rally Don Godfrey complet ed test flown B-25 first earlier year scheduled fly Rally got some great takeoff shots moved over near Don made pass over field happy way plane responding control inputs nounced going land As turning onto final big twin re fused respond Up elevator signals plowed ground off end runway walked end field saw pieces spread far 100 feet impact point As stood looking saddest sights modeling realized Bob Campbell getting ready fly Grumman Tigercat way down other end field started back hoping get time takeoff As trudged length field its long thought about recent experiences twins Could jinx vowed Bobs Tigercat crashed taking pictures would never point camera another twin-engined model rest life 54 Model Aviation Dick Hersheys 13-ft-span Grumman Goose about lift Californias Clearlake Its Ill-fated first flight Phil Karafilis Douglas A-20 Merwin Ranch purr its twin Quadras big part fascination twins As ship climbs out after takeoff R Phil didnt know yet left engine already saggingabout quit abruptly look closeiy can see beginning feed right aileron rudderbut too late Readers should reminded twin-engine Giant Scale planes shown probably weigh excess 55-lb limit AMA model aircraft hence would covered AMAl ia bility Insurance case accident Don Godfreys first 5-25 lifts off STARS Rally what turned out its last flight Bob thought camera might jinx twins Phil Karaf ills magnificent Beech D-18 earlier pictures January 1986 Issue detractions realism engines spark plugs hightenslon leads protruding below cowls After about dozen flights too bit dust Its several years later now Bobs Tigercat still going strong fact Bob has become prolific successful builder large multi-engined models know As working column got note him picture latest effort still under construction Theres another sad chapter story unfortunately California 1984 IMAA Fun Fly chance see Phil Karafilis beautiful Beech D-18 already made about 10 flights Phil made two flights day clicked away madly finally fill picture-taking just relaxed watching Phil put bird through its paces made pass down field pulled up split-S somewhat nonscale maneuver suspect plane nev er stopped rolling however corkscrewed right ground least time didnt have camera pointed Well whats point war stories Am trying say multiengine models impractical Certainly Bob Campbell others have shown successful can morbid fascination crashes No dont like next modeler better learn what can times think magazines us write try ignore aspect hobby Its fact life people tend learn failure successbut ex amine failure ask So what Whys four horror stories Its always possible 100% certain cause aircraft crashes models full-scale some conclusions have reached cases best knowledge heres what happened Grumman Goose built information derived primarily photographs full-scale aircraft Very little detailed data available retrospect appears incidence built wing excessive fact understand after fact Dick shey received letter engineer worked original Goose indicated prototype same problem remains Dicks Goose being rebuilt another model er Im hoping hear suc cessful maiden flight soon Godfreys B-25 apparently vic tim inadequate structural strength tail surfaces stabilizer spar elevator hinges failed withstand flight loads possible control surface flutter crash Karafilis D-18 due battery failure Note above failures due way fact two engines plane Ive saved A-20 last because its demise due fact two engines quit unbalanced thrust threw plane out control did engine quit turned out flexible tubing fuel pickup inside port fuel tank come off brass tube feed-through cap As long plane sitting level engine could draw almost half fuel tank However nose-high attitude climbout after takeoff engine starved fuel port engine dead flight controls could overcome full-throttle thrust starboard engine time Phil real ized engine out too late same fuel tank problem singleengine model would have awkward would likely have resulted crashContinued page 139 ROUSH KITS USA Super Kwick Fil Span 70 Area 927 Power 75 12 Two Ugly Stick Span 70 Area 1290 Power 75 12 $9995 Kitten Span 45 Area 290 Power 15 19 $3495 EAA Acro ii Span 60 Area 1300 Power 75 1 8 19~ Introductory Price Direct Sales Only Send $100 Catalog ROUSH MFG 1728 Bywood St SE Canton OH 44707 216 484-6810 4 April 1986 55 Bob Campbell has almost finished latest long line extremely large multi-eng miniature aircraft quarterscale 1 3ft.span P38 Power will two 52 Cu Sache-Doimer engines CA MASK CA glue works wonders building models right Unfortunately gives off enough fumes knock vulture off carcass modelers have suffered medical problems after inhaling CA fumes take chances special vapor respirator filters CA fumeal soft face mask adjustable st raps comfortably fits face sizes easy breathing valve allows prolonged use providing dependable filtering concentrations up 1000 PPMl though rugged industrial mask light weight elimi nate fatigue Dont get gassed CA Get protected Order CA Mask today Just $1247 shipping cheaper hospital visit Money order Master Charge Visa include expiration date check allow 20 days clear Sorry no CODs Pelican Enterprises Inc 265 OXFORD LANE BLOOMINGDALE ILLINOIS 60108 P S Send catalog modelers safety supplies Yes Im sick CA fumes Send CA mask Enclosed $1247 shipping NAME ADDRESS_______________________ CITY STATE____________ ZIP____________ Li VISA Li MASTER Exp Date________ FOX GLOW PLUGS FOR THOSE WHO WANT THE BEST SHORT $119 toim J$119 AC SNORT $169 Si Rhodium twice expensive platinum s better glow plugs space age insulator costs glass crack use Job shops couldnt hold tolerances wanted metal partsso make ourselves though less 1 plug 500 fails glow FOX PLUGS THOSE WHO WANT THE BEST Visa MasterCard accepted F 0 CO 5306 TOWSON AVE FORT SMITH ARK 72901 15011 646 1656 RC Old-Timers/Mathews Continued page 53 non-SAM-era models Hal deBolt tells will soon start column early RC designs Model Airplane News Id like some material Free Flight same approximate time frame am particularly turned PAA-Load both large small designs wartime goodies such Kid etc some really attractive sport-types such Pacificoaster last column Any photos would greatly appreciated Naturally puts would helpful well Two examples sort thing thinking Veco Sioux Bill Winters Midwest Sniffer enlargements published Flying Models few years back could get excited about sort conceptor impor tant youve tried itwould please drop line Dee B Mathews 8420 Nantucket Wichita KS 67212 RC Giant Scale/Beckman Continued page 55 Conclusion least conclusion Twins multi-engined models dont have considered terrible course theyre going compli cated turns out fail its pretty much same reasons models fall moral story learn failures apply lessons new project Pretty soon failures get few far between Bob Beckman 8248 Holly Grove Ct Manassas VA 22110 RC Pylon Racing/Hager Continued page 56 valve train reaches point valves dont follow bump cam may hit piston 14 x 10 prop its resulting rpm combination will keep well away since engines will run mid 8OOOs ground 10000 air diving three approved engines have redlines well past 12000 rpm Since racing need speed get pitch has increase because four-stroke engines now roughly 10000 rpm saw 15000 two-stroke 60 air Assuming 100 mph before seven-in pitch 15000 rpm now need 10 inches pitch 10000 rpm same speed 7 x 15000 approximately equals 10 x 10000 An added bonus larger prop efficient smaller thrust consistent rpm doesnt fall off turn since four-stroke lugs better meaning doesnt slow down much same ap plies takeoff climbing giving forgiving flight envelope can begin realize what have heard before propeller matching plane engine very important Back power torque Horsepower always combination torque rpm HP UE x RPM x k Torque twisting ability engine crankshaft have lugger always occurs lower rpm horsepow er peak 12 bigger engine has torque 60 half its size 12 generates torque much lower rpm Thats 12 11000 rpm 60 17000 rpm can both rated 16 horsepower just develop different set conditions Two-strokes have become powerhouses because easy increase rpm Look characteristics three engines see HP developed 12 cubic inch four-stroke 60 cubic inch two-stroke 45 cubic inch twostroke ducted fan engine deliver ap proximately 16 HP graph front column RH Torque climbs drops off approximately 2A HP max imum HP keeps climbing after torque drops because rpm still climbing torque drops faster rpm climbs HP starts drop hot engine sharper peaks types engines dif ficult set useful certain props Typically l2s use 13/15-inch prop 60s 11-inch 45s 5/9 inches 45s can actually develop HP cant use because dont have torque turn bigger props need larger prop higher-speed engine wont let engine get its horsepower peak doesnt matter horses liter ature says its rated Look curves 12 closely graph front column BH An engine doesnt develop HP automatically smaller prop just lets get up torque curve closer HP peak raised peak hotter engine may have shifted lower torque-curve anyway Horsepower Hop-up As long compare engines using same prop extra horsepower simple sounds since rpm wont go up itself unless changes made engine hop-up. engine de signed differently torque must creased some other way since rpm must go up takes torque easiest way power let rev. smaller prop less pitchbut allowed fore back torque increase THE LEADER IN COM PETITION NEW i 4 CYCLE THP DESIGN PRICE f 299 379 14479 15689 16989 NEW F 4 j NEW HIGH TECH AIRFOIL SECTION lOTO 20% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUEL PROOF HIGH LUSTER FINISH DIAPITCHPRICE 534149 634149 72833456179 833/,4568189 845667199 9456677199 104S667209 106W8W209 106EW219 ii46777/,7I,8229 115W229 11SEW239 1167239 124W279 125W279 1256279 1356349 1456459 1556659 164VzN989 16678969 PROPELLERS April1986 139 TAILORED HELICAL PITCH DEVELOPED TO GIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALL THE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW PITCH THP 86 77 8 877 8 677 8 67 678 PRO SERIES 3 RC PYLON RACING SERIES 500 DIA PITCH PRICE 7SN 5/N279 8I 6/,7/z78 299 SERIES 400C 8 66777 289 9777/289 W WIDE BLADE EW EXTRA WIDE N NARROW
Edition: Model Aviation - 1986/04
Page Numbers: 54, 55, 139
Radio Control Giant Scale Bob Beckman THOSE TERRIBLE TWOS Most mod elers fascinated twin-engined air craft. know am multi-engine models have reputation being diffi cult difficult build difficult fly difficult keep crashing Hence months title few years ago spectator series events seemed prove having two engines can terrible happened time span less two months spread out California New York started Clearlake California Dick Hersheys quarter-scale Grumman Goose ready its first flight wife Sacramento visit include fly-in Merwin Ranch Lee Taylor heard town told Gooses first flight scheduled next day Thursday too good miss Evelyn scrapped original plans rest week made three-hour drive Clearlake early next morning arrived just Dick crew getting big bird ready Goose launched crew two us tagging along boarded flat-decked pontoon boat headed out lake Lee Taylor test pilot made several high-speed taxi runs feel bird out reported aircraft felt tail heavy headed shore make some changes total six pounds lead placed far forward possible added before Lee felt comfortable balance headed out lake again found wind shifted Up now takeoff runs out lake now would have made toward shoreline meant moving farther out leave plenty space between plane spectators houses shore time takeoff run picture perfect big amphibian lifted off climbed out just like real thing Lee made shallow climbing 1800 turn head back out lake leveled off about 100 feet no warning tail suddenly dropped plane flipped onto its back rolling dropped straight lake video tapes made flight have post mortems Ill tell some conclu sions later Two days after Merwin Ranch Eagle Squadrons fabulous fly-ins Phil Kara filis planning have twinQuadra-powered Douglas A-20 its malden flight Since plane flown before could participate normal activity Phil planned fly evening after regular flying completed turned out peoDle wanted see theres fasci nation twins again Event Director agreed let Phil fly during noon break Phil fired up engines taxied out flight line smoothly fed full throttle aircraft accelerated rolling straight string rotated lifted off started climbing out Suddenly port engine sputtered died plane rolled left plunged ground Agaln Ill leave postmortem later took place May Cali fornia July Olean NY STARS Rally Don Godfrey complet ed test flown B-25 first earlier year scheduled fly Rally got some great takeoff shots moved over near Don made pass over field happy way plane responding control inputs nounced going land As turning onto final big twin re fused respond Up elevator signals plowed ground off end runway walked end field saw pieces spread far 100 feet impact point As stood looking saddest sights modeling realized Bob Campbell getting ready fly Grumman Tigercat way down other end field started back hoping get time takeoff As trudged length field its long thought about recent experiences twins Could jinx vowed Bobs Tigercat crashed taking pictures would never point camera another twin-engined model rest life 54 Model Aviation Dick Hersheys 13-ft-span Grumman Goose about lift Californias Clearlake Its Ill-fated first flight Phil Karafilis Douglas A-20 Merwin Ranch purr its twin Quadras big part fascination twins As ship climbs out after takeoff R Phil didnt know yet left engine already saggingabout quit abruptly look closeiy can see beginning feed right aileron rudderbut too late Readers should reminded twin-engine Giant Scale planes shown probably weigh excess 55-lb limit AMA model aircraft hence would covered AMAl ia bility Insurance case accident Don Godfreys first 5-25 lifts off STARS Rally what turned out its last flight Bob thought camera might jinx twins Phil Karaf ills magnificent Beech D-18 earlier pictures January 1986 Issue detractions realism engines spark plugs hightenslon leads protruding below cowls After about dozen flights too bit dust Its several years later now Bobs Tigercat still going strong fact Bob has become prolific successful builder large multi-engined models know As working column got note him picture latest effort still under construction Theres another sad chapter story unfortunately California 1984 IMAA Fun Fly chance see Phil Karafilis beautiful Beech D-18 already made about 10 flights Phil made two flights day clicked away madly finally fill picture-taking just relaxed watching Phil put bird through its paces made pass down field pulled up split-S somewhat nonscale maneuver suspect plane nev er stopped rolling however corkscrewed right ground least time didnt have camera pointed Well whats point war stories Am trying say multiengine models impractical Certainly Bob Campbell others have shown successful can morbid fascination crashes No dont like next modeler better learn what can times think magazines us write try ignore aspect hobby Its fact life people tend learn failure successbut ex amine failure ask So what Whys four horror stories Its always possible 100% certain cause aircraft crashes models full-scale some conclusions have reached cases best knowledge heres what happened Grumman Goose built information derived primarily photographs full-scale aircraft Very little detailed data available retrospect appears incidence built wing excessive fact understand after fact Dick shey received letter engineer worked original Goose indicated prototype same problem remains Dicks Goose being rebuilt another model er Im hoping hear suc cessful maiden flight soon Godfreys B-25 apparently vic tim inadequate structural strength tail surfaces stabilizer spar elevator hinges failed withstand flight loads possible control surface flutter crash Karafilis D-18 due battery failure Note above failures due way fact two engines plane Ive saved A-20 last because its demise due fact two engines quit unbalanced thrust threw plane out control did engine quit turned out flexible tubing fuel pickup inside port fuel tank come off brass tube feed-through cap As long plane sitting level engine could draw almost half fuel tank However nose-high attitude climbout after takeoff engine starved fuel port engine dead flight controls could overcome full-throttle thrust starboard engine time Phil real ized engine out too late same fuel tank problem singleengine model would have awkward would likely have resulted crashContinued page 139 ROUSH KITS USA Super Kwick Fil Span 70 Area 927 Power 75 12 Two Ugly Stick Span 70 Area 1290 Power 75 12 $9995 Kitten Span 45 Area 290 Power 15 19 $3495 EAA Acro ii Span 60 Area 1300 Power 75 1 8 19~ Introductory Price Direct Sales Only Send $100 Catalog ROUSH MFG 1728 Bywood St SE Canton OH 44707 216 484-6810 4 April 1986 55 Bob Campbell has almost finished latest long line extremely large multi-eng miniature aircraft quarterscale 1 3ft.span P38 Power will two 52 Cu Sache-Doimer engines CA MASK CA glue works wonders building models right Unfortunately gives off enough fumes knock vulture off carcass modelers have suffered medical problems after inhaling CA fumes take chances special vapor respirator filters CA fumeal soft face mask adjustable st raps comfortably fits face sizes easy breathing valve allows prolonged use providing dependable filtering concentrations up 1000 PPMl though rugged industrial mask light weight elimi nate fatigue Dont get gassed CA Get protected Order CA Mask today Just $1247 shipping cheaper hospital visit Money order Master Charge Visa include expiration date check allow 20 days clear Sorry no CODs Pelican Enterprises Inc 265 OXFORD LANE BLOOMINGDALE ILLINOIS 60108 P S Send catalog modelers safety supplies Yes Im sick CA fumes Send CA mask Enclosed $1247 shipping NAME ADDRESS_______________________ CITY STATE____________ ZIP____________ Li VISA Li MASTER Exp Date________ FOX GLOW PLUGS FOR THOSE WHO WANT THE BEST SHORT $119 toim J$119 AC SNORT $169 Si Rhodium twice expensive platinum s better glow plugs space age insulator costs glass crack use Job shops couldnt hold tolerances wanted metal partsso make ourselves though less 1 plug 500 fails glow FOX PLUGS THOSE WHO WANT THE BEST Visa MasterCard accepted F 0 CO 5306 TOWSON AVE FORT SMITH ARK 72901 15011 646 1656 RC Old-Timers/Mathews Continued page 53 non-SAM-era models Hal deBolt tells will soon start column early RC designs Model Airplane News Id like some material Free Flight same approximate time frame am particularly turned PAA-Load both large small designs wartime goodies such Kid etc some really attractive sport-types such Pacificoaster last column Any photos would greatly appreciated Naturally puts would helpful well Two examples sort thing thinking Veco Sioux Bill Winters Midwest Sniffer enlargements published Flying Models few years back could get excited about sort conceptor impor tant youve tried itwould please drop line Dee B Mathews 8420 Nantucket Wichita KS 67212 RC Giant Scale/Beckman Continued page 55 Conclusion least conclusion Twins multi-engined models dont have considered terrible course theyre going compli cated turns out fail its pretty much same reasons models fall moral story learn failures apply lessons new project Pretty soon failures get few far between Bob Beckman 8248 Holly Grove Ct Manassas VA 22110 RC Pylon Racing/Hager Continued page 56 valve train reaches point valves dont follow bump cam may hit piston 14 x 10 prop its resulting rpm combination will keep well away since engines will run mid 8OOOs ground 10000 air diving three approved engines have redlines well past 12000 rpm Since racing need speed get pitch has increase because four-stroke engines now roughly 10000 rpm saw 15000 two-stroke 60 air Assuming 100 mph before seven-in pitch 15000 rpm now need 10 inches pitch 10000 rpm same speed 7 x 15000 approximately equals 10 x 10000 An added bonus larger prop efficient smaller thrust consistent rpm doesnt fall off turn since four-stroke lugs better meaning doesnt slow down much same ap plies takeoff climbing giving forgiving flight envelope can begin realize what have heard before propeller matching plane engine very important Back power torque Horsepower always combination torque rpm HP UE x RPM x k Torque twisting ability engine crankshaft have lugger always occurs lower rpm horsepow er peak 12 bigger engine has torque 60 half its size 12 generates torque much lower rpm Thats 12 11000 rpm 60 17000 rpm can both rated 16 horsepower just develop different set conditions Two-strokes have become powerhouses because easy increase rpm Look characteristics three engines see HP developed 12 cubic inch four-stroke 60 cubic inch two-stroke 45 cubic inch twostroke ducted fan engine deliver ap proximately 16 HP graph front column RH Torque climbs drops off approximately 2A HP max imum HP keeps climbing after torque drops because rpm still climbing torque drops faster rpm climbs HP starts drop hot engine sharper peaks types engines dif ficult set useful certain props Typically l2s use 13/15-inch prop 60s 11-inch 45s 5/9 inches 45s can actually develop HP cant use because dont have torque turn bigger props need larger prop higher-speed engine wont let engine get its horsepower peak doesnt matter horses liter ature says its rated Look curves 12 closely graph front column BH An engine doesnt develop HP automatically smaller prop just lets get up torque curve closer HP peak raised peak hotter engine may have shifted lower torque-curve anyway Horsepower Hop-up As long compare engines using same prop extra horsepower simple sounds since rpm wont go up itself unless changes made engine hop-up. engine de signed differently torque must creased some other way since rpm must go up takes torque easiest way power let rev. smaller prop less pitchbut allowed fore back torque increase THE LEADER IN COM PETITION NEW i 4 CYCLE THP DESIGN PRICE f 299 379 14479 15689 16989 NEW F 4 j NEW HIGH TECH AIRFOIL SECTION lOTO 20% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUEL PROOF HIGH LUSTER FINISH DIAPITCHPRICE 534149 634149 72833456179 833/,4568189 845667199 9456677199 104S667209 106W8W209 106EW219 ii46777/,7I,8229 115W229 11SEW239 1167239 124W279 125W279 1256279 1356349 1456459 1556659 164VzN989 16678969 PROPELLERS April1986 139 TAILORED HELICAL PITCH DEVELOPED TO GIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALL THE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW PITCH THP 86 77 8 877 8 677 8 67 678 PRO SERIES 3 RC PYLON RACING SERIES 500 DIA PITCH PRICE 7SN 5/N279 8I 6/,7/z78 299 SERIES 400C 8 66777 289 9777/289 W WIDE BLADE EW EXTRA WIDE N NARROW