Radio Control Scale Bob&Dol lyWiseher INSTABILITY Revisited model splendid example scale beauty culmination years earnest effort moment builder has awaited excitement builds engine started needle valve set optimum checked again certain controls functional plane taxied take off position throttle opened accel erates down runway lifts off too early flips its back sickening sound returns earth parts scatter ing What happened pilot error hidden flaw construction Radio problems Probably real culprit Too often hear models difficult handle whether kit scratch built complaint heard involves tendency snap-roll usually during takeoff landing turning man euversand kit designer producer gets blame Numerous faults con struction balance can result de structive snap-roll Warped wings caused working warped work bench too tight covering material can result condition known wash-in angle incidence increases toward wing tip error results tips stalling before wing root cure flat working surface use low shrink covering materials dope slow flight during take-off land ing up elevator being employed increase lift compensating lack forward speed wing greater cidence both tips will experience tip stall sudden loss lift tip causing snap-roll ground good fortune such plane may get air letting fly off ground use excessive up elevator control will proceed snap-roll during first steep turn elevator used hold nose up As experiment show loss lift during turn day bright sunlight lift model off ground observe size wing shadow model rotated banked position turn reduction shadow size proportion loss lift against constant pull gravity regain sufficient lift maintaining al titude use up elevator increase angle attack adversely warped wing can produce snap-roll would prefer condition tips stall after wing root obtain positive stability some cases provi 24 Model Aviation Bjorquist Sweden flew Jodel Russian 7cc Paoyra engine recent Woodvale World Championships Large 81 -in span plane weighed almost 11 pounds scale Flown Leonard McCoy 1978 Southwestern Championships maneuverable japanese Zero fighter captured 5th place Zero beautiful proportions lines Pic Randy Randolph Stars-andstripes-decorated Chipmunk handiwork Jarrold Schmidt Stand Off Scale classic powered Merco engine Would look real pilot Larry Kruse photo sion has made design prototype aircraft intentionally building warp opposite wash out direction planes leading edge lower tip root relative trailing edge may constant change root tip could incorporated extreme end Lateral stability maintained during periods increased angle attack method wing prototype employed wash-out model should also use insure stable flight have found models fly similar full-size plane Wash-out stability inducing feature useful scale models intended inverted flight since would reduce stability Another method has minimum effect scale appearance increase wing thickness tip tapered wing root airfoil has thickness 13% chord tip thickness made 14% 15% change percentage produces wing will stall first root tips maintaining stability cutting foam wing cores transition easily done proper templates Warped wings reason inadvertent snap-rolls An over-weight model greater normal elevator travel can cause same problem espe cially under-powered model climbs away flier aware slight change angle caused imperceptible stick movement could stall over-burdened wing plane begins fall flier cannot force himself thing could save plane push stick forward regain flying speed stead does what natural pulls stick back stop downward travel result snap-roll ground cure reduce elevator travel tiny stick movement does push wing over brink unexpected stalled condition planes elevator needs travel far enough reduce speed landing over-weight condition described rare 23 planes flown recent Scale World Championships Woodvale two under ten pounds near 11-pound weight limit 13 pounds 1979 large enough wing areas weights permissible High weight combined low wing area undetected warp can spell disaster Emeraude has built-in 3-degree wash out wing tips prevent tip stall one-inch elevator travel neu tral 10-pound plane will snap-roll bottom loop speed greatest point loop G-forces also great prevent elevator travel cut half 1oops made larger heart breaking tear plane add longer elevator horn proved worthwhile Speed no guarantee snap-roll February 1 979 25 will occur pilot knows about high speed stalls learned flight instructor asked throttle opened build speed followed ever steepening turn using elevator tighten turn until plane snapped over top spin snap-roll horizontal tail spin prolonged will terminate vertical spin Relaxing elevator control applying bit down elevator stops rotation subse quent dive regain flying speed Sudden application up elevator during dive will result another snap re-entry spin Tail heaviness enemy scale modelers can cause same problems snap rolls warp over-weight can vicious unless model flown extreme care obvious cure build tail light add weight nose nose-heavy condition increases stability decreases control response Such plane almost impossible place intentional tail spin some wings small changes center gravity location have adverse effect stability CG must checked carefully especially flat-bottomed airfoils Since have indicated elevator travel critical follows stabilizer angle setting relative wing also considered stabilizer leading edge set too low can also lead snap roll tendencies Quite often angular dif ference between stabilizer wing prototype greater what used modeling compensate heavy engine reduce difference rais ing stabilizer leading edge plane may become unstable pitch re spect cannot always produce true scale model unless servo added ad justing stabilizer angle flight Aileron travel has little snaproll instability except overly sensitive ailerons can lead placing model unexpected positions Large aileron travel introduces drag can slow plane stall point Friese-type ailerons hinge point below wing surface behind aileron leading used induce drag upward de flected aileron help balance drag down aileron intended overcome tendency plane yaw di rection opposite turn resulting drag both wing tips may sufficient cause stall heavily loaded wing dur ing high-G turn cure reduction aileron travel Friese-type ailerons leading edge up aileron dips below bottom wing will deflect air through slot make aileron very effective reason models deflection can reduced Ailerons first control lose effectiveness approaching stall followed elevators rudder remaining responsive right up stall point means wing has dropped plane approaches stall during landing can raised 26 Model Aviation using rudder accelerate low wing thereby raise flying full-size plane becomes automatic response model requires same presence mind used switching rudder ailerons during takeoff Flight realism improved dramatically reducing aileron elevator travel contest thing really turns judges off jerky flight plane over-sensitive controls What contestant needs plane makes him look good flying realistic manner particularly rolling out turns between maneuvers model leaps off runway given touch elevator loses points hurts first impression should possible necessary hold stick forward slightly prevent early jump-off takeoff speed has established slight relaxing back stick should give smooth lift off gentle climb risk snap roll wing warp misplaced CG just likely victimize quarter-scale plane other snap-roll runway impact shattering especially pocketbook home club have four snap-roll accidents recent past three scale models monster scale ac cident ratio extends throughout land must awful lot broken balsa Often overlooked cause snaprolls airfoil shape particularly leading edge nicely rounded edge surance against snap An edge left too sharp because lack carving sanding can lead problem items mentioned will needless repetition experience scale modelers Frequent occurence type accident indicates needed discussed now scale modeling has gained popularity Information Sources Looking good scale drawings prototypes Write lists catalogs National Air Space Museum Washington DC 20560 List 3-view drawings Scale Aerotech 21028 Golden Triangle Rd Saugus CA 92350 List Koko-Fan Japanese 3-views Send stamped envelope Morrison Repla-Tech 48500 McKenzie Hwy Vida OR 97488 $100 catalog plane drawings famous race plane drawings Historical Aviation Album p 0 Box 33 Temple City CA 91780 List 3-view scale drawings famous airplanes past American Air Racing Society P 0 Box 121 South Euclid OH 44121 List 3-view race plane drawings International Scale Plan Service Jim Newman 4 Cleveland Terrace Hobart IN 46342 List scale plans 3-views Scale Craft PO Box 4231 Whittier CA 90607 List 3-view drawings Send stamped envelope Bob Holman Plans PO Box 741 San Bernardino CA 92402 Best scale cata log list Aeromodeller 3-views Does anyone read column would like letters questions readers February 1979 27 Bob Dolly Wischer Rt 1 S-221 Lapham Peak Road Delafield WI 53018 Twins gaining popularity Cessna 310 work Stanley Dzon Built Royal kit plane finished K&B Superpoxy has 05 Max 40s
Edition: Model Aviation - 1979/02
Page Numbers: 24, 25, 26, 27
Radio Control Scale Bob&Dol lyWiseher INSTABILITY Revisited model splendid example scale beauty culmination years earnest effort moment builder has awaited excitement builds engine started needle valve set optimum checked again certain controls functional plane taxied take off position throttle opened accel erates down runway lifts off too early flips its back sickening sound returns earth parts scatter ing What happened pilot error hidden flaw construction Radio problems Probably real culprit Too often hear models difficult handle whether kit scratch built complaint heard involves tendency snap-roll usually during takeoff landing turning man euversand kit designer producer gets blame Numerous faults con struction balance can result de structive snap-roll Warped wings caused working warped work bench too tight covering material can result condition known wash-in angle incidence increases toward wing tip error results tips stalling before wing root cure flat working surface use low shrink covering materials dope slow flight during take-off land ing up elevator being employed increase lift compensating lack forward speed wing greater cidence both tips will experience tip stall sudden loss lift tip causing snap-roll ground good fortune such plane may get air letting fly off ground use excessive up elevator control will proceed snap-roll during first steep turn elevator used hold nose up As experiment show loss lift during turn day bright sunlight lift model off ground observe size wing shadow model rotated banked position turn reduction shadow size proportion loss lift against constant pull gravity regain sufficient lift maintaining al titude use up elevator increase angle attack adversely warped wing can produce snap-roll would prefer condition tips stall after wing root obtain positive stability some cases provi 24 Model Aviation Bjorquist Sweden flew Jodel Russian 7cc Paoyra engine recent Woodvale World Championships Large 81 -in span plane weighed almost 11 pounds scale Flown Leonard McCoy 1978 Southwestern Championships maneuverable japanese Zero fighter captured 5th place Zero beautiful proportions lines Pic Randy Randolph Stars-andstripes-decorated Chipmunk handiwork Jarrold Schmidt Stand Off Scale classic powered Merco engine Would look real pilot Larry Kruse photo sion has made design prototype aircraft intentionally building warp opposite wash out direction planes leading edge lower tip root relative trailing edge may constant change root tip could incorporated extreme end Lateral stability maintained during periods increased angle attack method wing prototype employed wash-out model should also use insure stable flight have found models fly similar full-size plane Wash-out stability inducing feature useful scale models intended inverted flight since would reduce stability Another method has minimum effect scale appearance increase wing thickness tip tapered wing root airfoil has thickness 13% chord tip thickness made 14% 15% change percentage produces wing will stall first root tips maintaining stability cutting foam wing cores transition easily done proper templates Warped wings reason inadvertent snap-rolls An over-weight model greater normal elevator travel can cause same problem espe cially under-powered model climbs away flier aware slight change angle caused imperceptible stick movement could stall over-burdened wing plane begins fall flier cannot force himself thing could save plane push stick forward regain flying speed stead does what natural pulls stick back stop downward travel result snap-roll ground cure reduce elevator travel tiny stick movement does push wing over brink unexpected stalled condition planes elevator needs travel far enough reduce speed landing over-weight condition described rare 23 planes flown recent Scale World Championships Woodvale two under ten pounds near 11-pound weight limit 13 pounds 1979 large enough wing areas weights permissible High weight combined low wing area undetected warp can spell disaster Emeraude has built-in 3-degree wash out wing tips prevent tip stall one-inch elevator travel neu tral 10-pound plane will snap-roll bottom loop speed greatest point loop G-forces also great prevent elevator travel cut half 1oops made larger heart breaking tear plane add longer elevator horn proved worthwhile Speed no guarantee snap-roll February 1 979 25 will occur pilot knows about high speed stalls learned flight instructor asked throttle opened build speed followed ever steepening turn using elevator tighten turn until plane snapped over top spin snap-roll horizontal tail spin prolonged will terminate vertical spin Relaxing elevator control applying bit down elevator stops rotation subse quent dive regain flying speed Sudden application up elevator during dive will result another snap re-entry spin Tail heaviness enemy scale modelers can cause same problems snap rolls warp over-weight can vicious unless model flown extreme care obvious cure build tail light add weight nose nose-heavy condition increases stability decreases control response Such plane almost impossible place intentional tail spin some wings small changes center gravity location have adverse effect stability CG must checked carefully especially flat-bottomed airfoils Since have indicated elevator travel critical follows stabilizer angle setting relative wing also considered stabilizer leading edge set too low can also lead snap roll tendencies Quite often angular dif ference between stabilizer wing prototype greater what used modeling compensate heavy engine reduce difference rais ing stabilizer leading edge plane may become unstable pitch re spect cannot always produce true scale model unless servo added ad justing stabilizer angle flight Aileron travel has little snaproll instability except overly sensitive ailerons can lead placing model unexpected positions Large aileron travel introduces drag can slow plane stall point Friese-type ailerons hinge point below wing surface behind aileron leading used induce drag upward de flected aileron help balance drag down aileron intended overcome tendency plane yaw di rection opposite turn resulting drag both wing tips may sufficient cause stall heavily loaded wing dur ing high-G turn cure reduction aileron travel Friese-type ailerons leading edge up aileron dips below bottom wing will deflect air through slot make aileron very effective reason models deflection can reduced Ailerons first control lose effectiveness approaching stall followed elevators rudder remaining responsive right up stall point means wing has dropped plane approaches stall during landing can raised 26 Model Aviation using rudder accelerate low wing thereby raise flying full-size plane becomes automatic response model requires same presence mind used switching rudder ailerons during takeoff Flight realism improved dramatically reducing aileron elevator travel contest thing really turns judges off jerky flight plane over-sensitive controls What contestant needs plane makes him look good flying realistic manner particularly rolling out turns between maneuvers model leaps off runway given touch elevator loses points hurts first impression should possible necessary hold stick forward slightly prevent early jump-off takeoff speed has established slight relaxing back stick should give smooth lift off gentle climb risk snap roll wing warp misplaced CG just likely victimize quarter-scale plane other snap-roll runway impact shattering especially pocketbook home club have four snap-roll accidents recent past three scale models monster scale ac cident ratio extends throughout land must awful lot broken balsa Often overlooked cause snaprolls airfoil shape particularly leading edge nicely rounded edge surance against snap An edge left too sharp because lack carving sanding can lead problem items mentioned will needless repetition experience scale modelers Frequent occurence type accident indicates needed discussed now scale modeling has gained popularity Information Sources Looking good scale drawings prototypes Write lists catalogs National Air Space Museum Washington DC 20560 List 3-view drawings Scale Aerotech 21028 Golden Triangle Rd Saugus CA 92350 List Koko-Fan Japanese 3-views Send stamped envelope Morrison Repla-Tech 48500 McKenzie Hwy Vida OR 97488 $100 catalog plane drawings famous race plane drawings Historical Aviation Album p 0 Box 33 Temple City CA 91780 List 3-view scale drawings famous airplanes past American Air Racing Society P 0 Box 121 South Euclid OH 44121 List 3-view race plane drawings International Scale Plan Service Jim Newman 4 Cleveland Terrace Hobart IN 46342 List scale plans 3-views Scale Craft PO Box 4231 Whittier CA 90607 List 3-view drawings Send stamped envelope Bob Holman Plans PO Box 741 San Bernardino CA 92402 Best scale cata log list Aeromodeller 3-views Does anyone read column would like letters questions readers February 1979 27 Bob Dolly Wischer Rt 1 S-221 Lapham Peak Road Delafield WI 53018 Twins gaining popularity Cessna 310 work Stanley Dzon Built Royal kit plane finished K&B Superpoxy has 05 Max 40s
Edition: Model Aviation - 1979/02
Page Numbers: 24, 25, 26, 27
Radio Control Scale Bob&Dol lyWiseher INSTABILITY Revisited model splendid example scale beauty culmination years earnest effort moment builder has awaited excitement builds engine started needle valve set optimum checked again certain controls functional plane taxied take off position throttle opened accel erates down runway lifts off too early flips its back sickening sound returns earth parts scatter ing What happened pilot error hidden flaw construction Radio problems Probably real culprit Too often hear models difficult handle whether kit scratch built complaint heard involves tendency snap-roll usually during takeoff landing turning man euversand kit designer producer gets blame Numerous faults con struction balance can result de structive snap-roll Warped wings caused working warped work bench too tight covering material can result condition known wash-in angle incidence increases toward wing tip error results tips stalling before wing root cure flat working surface use low shrink covering materials dope slow flight during take-off land ing up elevator being employed increase lift compensating lack forward speed wing greater cidence both tips will experience tip stall sudden loss lift tip causing snap-roll ground good fortune such plane may get air letting fly off ground use excessive up elevator control will proceed snap-roll during first steep turn elevator used hold nose up As experiment show loss lift during turn day bright sunlight lift model off ground observe size wing shadow model rotated banked position turn reduction shadow size proportion loss lift against constant pull gravity regain sufficient lift maintaining al titude use up elevator increase angle attack adversely warped wing can produce snap-roll would prefer condition tips stall after wing root obtain positive stability some cases provi 24 Model Aviation Bjorquist Sweden flew Jodel Russian 7cc Paoyra engine recent Woodvale World Championships Large 81 -in span plane weighed almost 11 pounds scale Flown Leonard McCoy 1978 Southwestern Championships maneuverable japanese Zero fighter captured 5th place Zero beautiful proportions lines Pic Randy Randolph Stars-andstripes-decorated Chipmunk handiwork Jarrold Schmidt Stand Off Scale classic powered Merco engine Would look real pilot Larry Kruse photo sion has made design prototype aircraft intentionally building warp opposite wash out direction planes leading edge lower tip root relative trailing edge may constant change root tip could incorporated extreme end Lateral stability maintained during periods increased angle attack method wing prototype employed wash-out model should also use insure stable flight have found models fly similar full-size plane Wash-out stability inducing feature useful scale models intended inverted flight since would reduce stability Another method has minimum effect scale appearance increase wing thickness tip tapered wing root airfoil has thickness 13% chord tip thickness made 14% 15% change percentage produces wing will stall first root tips maintaining stability cutting foam wing cores transition easily done proper templates Warped wings reason inadvertent snap-rolls An over-weight model greater normal elevator travel can cause same problem espe cially under-powered model climbs away flier aware slight change angle caused imperceptible stick movement could stall over-burdened wing plane begins fall flier cannot force himself thing could save plane push stick forward regain flying speed stead does what natural pulls stick back stop downward travel result snap-roll ground cure reduce elevator travel tiny stick movement does push wing over brink unexpected stalled condition planes elevator needs travel far enough reduce speed landing over-weight condition described rare 23 planes flown recent Scale World Championships Woodvale two under ten pounds near 11-pound weight limit 13 pounds 1979 large enough wing areas weights permissible High weight combined low wing area undetected warp can spell disaster Emeraude has built-in 3-degree wash out wing tips prevent tip stall one-inch elevator travel neu tral 10-pound plane will snap-roll bottom loop speed greatest point loop G-forces also great prevent elevator travel cut half 1oops made larger heart breaking tear plane add longer elevator horn proved worthwhile Speed no guarantee snap-roll February 1 979 25 will occur pilot knows about high speed stalls learned flight instructor asked throttle opened build speed followed ever steepening turn using elevator tighten turn until plane snapped over top spin snap-roll horizontal tail spin prolonged will terminate vertical spin Relaxing elevator control applying bit down elevator stops rotation subse quent dive regain flying speed Sudden application up elevator during dive will result another snap re-entry spin Tail heaviness enemy scale modelers can cause same problems snap rolls warp over-weight can vicious unless model flown extreme care obvious cure build tail light add weight nose nose-heavy condition increases stability decreases control response Such plane almost impossible place intentional tail spin some wings small changes center gravity location have adverse effect stability CG must checked carefully especially flat-bottomed airfoils Since have indicated elevator travel critical follows stabilizer angle setting relative wing also considered stabilizer leading edge set too low can also lead snap roll tendencies Quite often angular dif ference between stabilizer wing prototype greater what used modeling compensate heavy engine reduce difference rais ing stabilizer leading edge plane may become unstable pitch re spect cannot always produce true scale model unless servo added ad justing stabilizer angle flight Aileron travel has little snaproll instability except overly sensitive ailerons can lead placing model unexpected positions Large aileron travel introduces drag can slow plane stall point Friese-type ailerons hinge point below wing surface behind aileron leading used induce drag upward de flected aileron help balance drag down aileron intended overcome tendency plane yaw di rection opposite turn resulting drag both wing tips may sufficient cause stall heavily loaded wing dur ing high-G turn cure reduction aileron travel Friese-type ailerons leading edge up aileron dips below bottom wing will deflect air through slot make aileron very effective reason models deflection can reduced Ailerons first control lose effectiveness approaching stall followed elevators rudder remaining responsive right up stall point means wing has dropped plane approaches stall during landing can raised 26 Model Aviation using rudder accelerate low wing thereby raise flying full-size plane becomes automatic response model requires same presence mind used switching rudder ailerons during takeoff Flight realism improved dramatically reducing aileron elevator travel contest thing really turns judges off jerky flight plane over-sensitive controls What contestant needs plane makes him look good flying realistic manner particularly rolling out turns between maneuvers model leaps off runway given touch elevator loses points hurts first impression should possible necessary hold stick forward slightly prevent early jump-off takeoff speed has established slight relaxing back stick should give smooth lift off gentle climb risk snap roll wing warp misplaced CG just likely victimize quarter-scale plane other snap-roll runway impact shattering especially pocketbook home club have four snap-roll accidents recent past three scale models monster scale ac cident ratio extends throughout land must awful lot broken balsa Often overlooked cause snaprolls airfoil shape particularly leading edge nicely rounded edge surance against snap An edge left too sharp because lack carving sanding can lead problem items mentioned will needless repetition experience scale modelers Frequent occurence type accident indicates needed discussed now scale modeling has gained popularity Information Sources Looking good scale drawings prototypes Write lists catalogs National Air Space Museum Washington DC 20560 List 3-view drawings Scale Aerotech 21028 Golden Triangle Rd Saugus CA 92350 List Koko-Fan Japanese 3-views Send stamped envelope Morrison Repla-Tech 48500 McKenzie Hwy Vida OR 97488 $100 catalog plane drawings famous race plane drawings Historical Aviation Album p 0 Box 33 Temple City CA 91780 List 3-view scale drawings famous airplanes past American Air Racing Society P 0 Box 121 South Euclid OH 44121 List 3-view race plane drawings International Scale Plan Service Jim Newman 4 Cleveland Terrace Hobart IN 46342 List scale plans 3-views Scale Craft PO Box 4231 Whittier CA 90607 List 3-view drawings Send stamped envelope Bob Holman Plans PO Box 741 San Bernardino CA 92402 Best scale cata log list Aeromodeller 3-views Does anyone read column would like letters questions readers February 1979 27 Bob Dolly Wischer Rt 1 S-221 Lapham Peak Road Delafield WI 53018 Twins gaining popularity Cessna 310 work Stanley Dzon Built Royal kit plane finished K&B Superpoxy has 05 Max 40s
Edition: Model Aviation - 1979/02
Page Numbers: 24, 25, 26, 27
Radio Control Scale Bob&Dol lyWiseher INSTABILITY Revisited model splendid example scale beauty culmination years earnest effort moment builder has awaited excitement builds engine started needle valve set optimum checked again certain controls functional plane taxied take off position throttle opened accel erates down runway lifts off too early flips its back sickening sound returns earth parts scatter ing What happened pilot error hidden flaw construction Radio problems Probably real culprit Too often hear models difficult handle whether kit scratch built complaint heard involves tendency snap-roll usually during takeoff landing turning man euversand kit designer producer gets blame Numerous faults con struction balance can result de structive snap-roll Warped wings caused working warped work bench too tight covering material can result condition known wash-in angle incidence increases toward wing tip error results tips stalling before wing root cure flat working surface use low shrink covering materials dope slow flight during take-off land ing up elevator being employed increase lift compensating lack forward speed wing greater cidence both tips will experience tip stall sudden loss lift tip causing snap-roll ground good fortune such plane may get air letting fly off ground use excessive up elevator control will proceed snap-roll during first steep turn elevator used hold nose up As experiment show loss lift during turn day bright sunlight lift model off ground observe size wing shadow model rotated banked position turn reduction shadow size proportion loss lift against constant pull gravity regain sufficient lift maintaining al titude use up elevator increase angle attack adversely warped wing can produce snap-roll would prefer condition tips stall after wing root obtain positive stability some cases provi 24 Model Aviation Bjorquist Sweden flew Jodel Russian 7cc Paoyra engine recent Woodvale World Championships Large 81 -in span plane weighed almost 11 pounds scale Flown Leonard McCoy 1978 Southwestern Championships maneuverable japanese Zero fighter captured 5th place Zero beautiful proportions lines Pic Randy Randolph Stars-andstripes-decorated Chipmunk handiwork Jarrold Schmidt Stand Off Scale classic powered Merco engine Would look real pilot Larry Kruse photo sion has made design prototype aircraft intentionally building warp opposite wash out direction planes leading edge lower tip root relative trailing edge may constant change root tip could incorporated extreme end Lateral stability maintained during periods increased angle attack method wing prototype employed wash-out model should also use insure stable flight have found models fly similar full-size plane Wash-out stability inducing feature useful scale models intended inverted flight since would reduce stability Another method has minimum effect scale appearance increase wing thickness tip tapered wing root airfoil has thickness 13% chord tip thickness made 14% 15% change percentage produces wing will stall first root tips maintaining stability cutting foam wing cores transition easily done proper templates Warped wings reason inadvertent snap-rolls An over-weight model greater normal elevator travel can cause same problem espe cially under-powered model climbs away flier aware slight change angle caused imperceptible stick movement could stall over-burdened wing plane begins fall flier cannot force himself thing could save plane push stick forward regain flying speed stead does what natural pulls stick back stop downward travel result snap-roll ground cure reduce elevator travel tiny stick movement does push wing over brink unexpected stalled condition planes elevator needs travel far enough reduce speed landing over-weight condition described rare 23 planes flown recent Scale World Championships Woodvale two under ten pounds near 11-pound weight limit 13 pounds 1979 large enough wing areas weights permissible High weight combined low wing area undetected warp can spell disaster Emeraude has built-in 3-degree wash out wing tips prevent tip stall one-inch elevator travel neu tral 10-pound plane will snap-roll bottom loop speed greatest point loop G-forces also great prevent elevator travel cut half 1oops made larger heart breaking tear plane add longer elevator horn proved worthwhile Speed no guarantee snap-roll February 1 979 25 will occur pilot knows about high speed stalls learned flight instructor asked throttle opened build speed followed ever steepening turn using elevator tighten turn until plane snapped over top spin snap-roll horizontal tail spin prolonged will terminate vertical spin Relaxing elevator control applying bit down elevator stops rotation subse quent dive regain flying speed Sudden application up elevator during dive will result another snap re-entry spin Tail heaviness enemy scale modelers can cause same problems snap rolls warp over-weight can vicious unless model flown extreme care obvious cure build tail light add weight nose nose-heavy condition increases stability decreases control response Such plane almost impossible place intentional tail spin some wings small changes center gravity location have adverse effect stability CG must checked carefully especially flat-bottomed airfoils Since have indicated elevator travel critical follows stabilizer angle setting relative wing also considered stabilizer leading edge set too low can also lead snap roll tendencies Quite often angular dif ference between stabilizer wing prototype greater what used modeling compensate heavy engine reduce difference rais ing stabilizer leading edge plane may become unstable pitch re spect cannot always produce true scale model unless servo added ad justing stabilizer angle flight Aileron travel has little snaproll instability except overly sensitive ailerons can lead placing model unexpected positions Large aileron travel introduces drag can slow plane stall point Friese-type ailerons hinge point below wing surface behind aileron leading used induce drag upward de flected aileron help balance drag down aileron intended overcome tendency plane yaw di rection opposite turn resulting drag both wing tips may sufficient cause stall heavily loaded wing dur ing high-G turn cure reduction aileron travel Friese-type ailerons leading edge up aileron dips below bottom wing will deflect air through slot make aileron very effective reason models deflection can reduced Ailerons first control lose effectiveness approaching stall followed elevators rudder remaining responsive right up stall point means wing has dropped plane approaches stall during landing can raised 26 Model Aviation using rudder accelerate low wing thereby raise flying full-size plane becomes automatic response model requires same presence mind used switching rudder ailerons during takeoff Flight realism improved dramatically reducing aileron elevator travel contest thing really turns judges off jerky flight plane over-sensitive controls What contestant needs plane makes him look good flying realistic manner particularly rolling out turns between maneuvers model leaps off runway given touch elevator loses points hurts first impression should possible necessary hold stick forward slightly prevent early jump-off takeoff speed has established slight relaxing back stick should give smooth lift off gentle climb risk snap roll wing warp misplaced CG just likely victimize quarter-scale plane other snap-roll runway impact shattering especially pocketbook home club have four snap-roll accidents recent past three scale models monster scale ac cident ratio extends throughout land must awful lot broken balsa Often overlooked cause snaprolls airfoil shape particularly leading edge nicely rounded edge surance against snap An edge left too sharp because lack carving sanding can lead problem items mentioned will needless repetition experience scale modelers Frequent occurence type accident indicates needed discussed now scale modeling has gained popularity Information Sources Looking good scale drawings prototypes Write lists catalogs National Air Space Museum Washington DC 20560 List 3-view drawings Scale Aerotech 21028 Golden Triangle Rd Saugus CA 92350 List Koko-Fan Japanese 3-views Send stamped envelope Morrison Repla-Tech 48500 McKenzie Hwy Vida OR 97488 $100 catalog plane drawings famous race plane drawings Historical Aviation Album p 0 Box 33 Temple City CA 91780 List 3-view scale drawings famous airplanes past American Air Racing Society P 0 Box 121 South Euclid OH 44121 List 3-view race plane drawings International Scale Plan Service Jim Newman 4 Cleveland Terrace Hobart IN 46342 List scale plans 3-views Scale Craft PO Box 4231 Whittier CA 90607 List 3-view drawings Send stamped envelope Bob Holman Plans PO Box 741 San Bernardino CA 92402 Best scale cata log list Aeromodeller 3-views Does anyone read column would like letters questions readers February 1979 27 Bob Dolly Wischer Rt 1 S-221 Lapham Peak Road Delafield WI 53018 Twins gaining popularity Cessna 310 work Stanley Dzon Built Royal kit plane finished K&B Superpoxy has 05 Max 40s