ne aspect control line models has always problem control system builder striving maneuverability often too sensitive allow airplane easily controlled other hand builder trying produce plane stable easy handle will probably find model lacks sensitivity An article Pro-Stunt News stated beginners try use control system too sensitive abilities suggested control system configured give reduced response thus giving model smoother control good idea flier will probably find airplane will lack necessary sensitivity his/her flying ability increases will forced build another airplane sensitive control system portions control line flight control system really doesnt have generate much control surface movement produce desired maneuver Precision Aerobatics model instance probably has three flight modes level flight round maneuvers square corners model maintain rock-solid level flight pilot probably has adjust control surfaces two tenths degree plane travels around circle difficult best usually results plane hunting slowly drifting up down goes around Some builders attempt compensate building some slop elevator linkage allows plane controlled flaps level flight larger movements control handle allow elevators come play Another method make elevators thinner stabilizer keeps partially out airstream reduces effect small control movements Both methods can effective will result non-linear control system response Circular maneuvers like loops probably require few degrees control surface deflection easier accomplish October 1994 57 -IeeplnePIn Scimi Authors Cessna Ag-Wagon uses Scimitar control system Largerthan-normal wing cutout allows sideways pushrod movement level flight However making perfectly round maneuver still requires accurate control sensitive touch pilot make round maneuvers easier perform builder can reduce sensitivity control system However will make following maneuver difficult execute Square corners require large abrupt control deflection No problem just pull handle fast can real problem comes want return straight flight path end turn small error repositioning handle will cause model overshoot bobble will result corner less 900 Since have walking sensitivitylcontrollability tightrope number years decided try invent new type control system would give reduced sensitivity needed maintain accurate control giving adequate response ensure good maneuverability result work area device call Scimitar bellcrank gave name because two curved slots remind curved swords carried soldiers guard harems Middle East RESPONSE OF CONVENTIONAL CONTROL SYSTEM DEGREES OF FLAP DEFLECTION 004ososo lo Ao - 10 DEGREES OF - o HANDLE - 00 Rotation - 40 --90 --60 --00 - - 90 FIGURE 2 will interested new bellcrank can help Precision Aerobatics fliers concerned both smooth control quick response Scimitar bellcrank will allow flier maintain good control airplane level flight doing round maneuvers Aerobatics pattern will also give quick response perform square maneuvers Navy Carrier jocks may find will give better control models during phases flight either quick response precise control needed Scale pilots will able perform finely controlled touch-and-gos having good response maneuvers EFFECT OF BIAS ON SCIMITAR PUSHROD RESPONSE % OF PUHSROD MAXIMUM MOVEMENT 10 BIAS NO BIAS -10Sot So So BELLCRANK OTATION A8 -70 40 --90 00 70 --00 90 FIGURE 3 October 1994 59 TOP VIEW SIDE VIEW FIGURE 1 might wish attempt part flight routines Before designing new device decided analyze present control system see what its response would look like plot its curve shown Figure X shape calculated using following parameters Line spacing handle 45 inches Line spacing belicrank 30 inches Pushrod moment bellcrank 10 inch Elevator moment 10 inch As can see response conventional system fairly linear curves ends due fact line spacing handle wider bellcrank slope curve goes through neutral point graph quite steep what makes conventional system sensitive curve Scimitar control system shown Figure X shape basically inverted cosine curve response system around neutral point quite slow allows Scimitar system give smooth control airplane level flight doing round figures As bellcrank rotates further response curve rapidly increases slope gives model quick response needed perform square maneuvers Scimitar bellcrank different conventional type pushrod has two spurs spurs reside two curved slots bellcrank rotated counterclockwise left spur would become active moving pushrod right applying up elevator right spur would move its slot inactive similar action would take place bellcrank rotated clockwise right spur pulling pushrod left applying down elevator left spur moves out its slot pushrod holes placed diameter line bellcrank would lot smooth response neutral too much handle deflection would required perform kind tight flying maneuvers first Scimitar bellcrank designed manner did work well reason desirable bias holes slightly off diameter line bellcrank Adding bias bellcrank improves response neutral point adding too much bias 100 makes system sensitive almost back conventional system again Notice distance center bellcrank left pushrod spur longer distance center right spur unequal spacing necessary because pushrod spurs move sideways bellcrank rotates well forward backward sideways movement subtracts pushing motion up elevator adding pulling movement down elevator Adjusting distances shown figure allows up down travels equal both surfaces achieve desired response curve system necessary use circular shape bellcrank means flexible leadout wires must used little danger wires slipping off bellcrank device because groove leadouts reside /4 inch deep line guides installed wing close bellcrank serve keep wires position pushrod free move its slots flying centrifugal force would probably sufficient keep pushrod its proper place ground might possible pushrod move out position jam its slots unless some method used prevent this reason small keeper spring used keeps pushrod position times since made very thin wire its effect noticeable operating controls Control line pilots know making airplane tailheavy will greatly improve its response also know model will difficult handle due increased sensitivity Because its relatively slow response neutral point Scimitar control system allows model balanced quite tailheavy causing normal controllability problems Scimitar bellcranks have built have made I/ aircraft plywood rim pieces /16 plywood makes device very strong easy fabricate special tools finished weight about ounce would like try make systems have put together detailed set instructions diagrams can use assemble install Ill glad mail copy you will send check amount $375 cover cost photocopies postage etc instructions include chart covers sizes applications would like custom-design system have written computer program runs under DOS Basic will allow cost 3/2-inch diskette $350 Write 325 Jennings Street Endicott NY 137604018 T POINT BELLCRANK DIAMETER BIAS BIAS ANGLE ANGLE 0 UP, HOLE DOWN HOLE 60 Model Aviation
Edition: Model Aviation - 1994/10
Page Numbers: 57, 59, 60
ne aspect control line models has always problem control system builder striving maneuverability often too sensitive allow airplane easily controlled other hand builder trying produce plane stable easy handle will probably find model lacks sensitivity An article Pro-Stunt News stated beginners try use control system too sensitive abilities suggested control system configured give reduced response thus giving model smoother control good idea flier will probably find airplane will lack necessary sensitivity his/her flying ability increases will forced build another airplane sensitive control system portions control line flight control system really doesnt have generate much control surface movement produce desired maneuver Precision Aerobatics model instance probably has three flight modes level flight round maneuvers square corners model maintain rock-solid level flight pilot probably has adjust control surfaces two tenths degree plane travels around circle difficult best usually results plane hunting slowly drifting up down goes around Some builders attempt compensate building some slop elevator linkage allows plane controlled flaps level flight larger movements control handle allow elevators come play Another method make elevators thinner stabilizer keeps partially out airstream reduces effect small control movements Both methods can effective will result non-linear control system response Circular maneuvers like loops probably require few degrees control surface deflection easier accomplish October 1994 57 -IeeplnePIn Scimi Authors Cessna Ag-Wagon uses Scimitar control system Largerthan-normal wing cutout allows sideways pushrod movement level flight However making perfectly round maneuver still requires accurate control sensitive touch pilot make round maneuvers easier perform builder can reduce sensitivity control system However will make following maneuver difficult execute Square corners require large abrupt control deflection No problem just pull handle fast can real problem comes want return straight flight path end turn small error repositioning handle will cause model overshoot bobble will result corner less 900 Since have walking sensitivitylcontrollability tightrope number years decided try invent new type control system would give reduced sensitivity needed maintain accurate control giving adequate response ensure good maneuverability result work area device call Scimitar bellcrank gave name because two curved slots remind curved swords carried soldiers guard harems Middle East RESPONSE OF CONVENTIONAL CONTROL SYSTEM DEGREES OF FLAP DEFLECTION 004ososo lo Ao - 10 DEGREES OF - o HANDLE - 00 Rotation - 40 --90 --60 --00 - - 90 FIGURE 2 will interested new bellcrank can help Precision Aerobatics fliers concerned both smooth control quick response Scimitar bellcrank will allow flier maintain good control airplane level flight doing round maneuvers Aerobatics pattern will also give quick response perform square maneuvers Navy Carrier jocks may find will give better control models during phases flight either quick response precise control needed Scale pilots will able perform finely controlled touch-and-gos having good response maneuvers EFFECT OF BIAS ON SCIMITAR PUSHROD RESPONSE % OF PUHSROD MAXIMUM MOVEMENT 10 BIAS NO BIAS -10Sot So So BELLCRANK OTATION A8 -70 40 --90 00 70 --00 90 FIGURE 3 October 1994 59 TOP VIEW SIDE VIEW FIGURE 1 might wish attempt part flight routines Before designing new device decided analyze present control system see what its response would look like plot its curve shown Figure X shape calculated using following parameters Line spacing handle 45 inches Line spacing belicrank 30 inches Pushrod moment bellcrank 10 inch Elevator moment 10 inch As can see response conventional system fairly linear curves ends due fact line spacing handle wider bellcrank slope curve goes through neutral point graph quite steep what makes conventional system sensitive curve Scimitar control system shown Figure X shape basically inverted cosine curve response system around neutral point quite slow allows Scimitar system give smooth control airplane level flight doing round figures As bellcrank rotates further response curve rapidly increases slope gives model quick response needed perform square maneuvers Scimitar bellcrank different conventional type pushrod has two spurs spurs reside two curved slots bellcrank rotated counterclockwise left spur would become active moving pushrod right applying up elevator right spur would move its slot inactive similar action would take place bellcrank rotated clockwise right spur pulling pushrod left applying down elevator left spur moves out its slot pushrod holes placed diameter line bellcrank would lot smooth response neutral too much handle deflection would required perform kind tight flying maneuvers first Scimitar bellcrank designed manner did work well reason desirable bias holes slightly off diameter line bellcrank Adding bias bellcrank improves response neutral point adding too much bias 100 makes system sensitive almost back conventional system again Notice distance center bellcrank left pushrod spur longer distance center right spur unequal spacing necessary because pushrod spurs move sideways bellcrank rotates well forward backward sideways movement subtracts pushing motion up elevator adding pulling movement down elevator Adjusting distances shown figure allows up down travels equal both surfaces achieve desired response curve system necessary use circular shape bellcrank means flexible leadout wires must used little danger wires slipping off bellcrank device because groove leadouts reside /4 inch deep line guides installed wing close bellcrank serve keep wires position pushrod free move its slots flying centrifugal force would probably sufficient keep pushrod its proper place ground might possible pushrod move out position jam its slots unless some method used prevent this reason small keeper spring used keeps pushrod position times since made very thin wire its effect noticeable operating controls Control line pilots know making airplane tailheavy will greatly improve its response also know model will difficult handle due increased sensitivity Because its relatively slow response neutral point Scimitar control system allows model balanced quite tailheavy causing normal controllability problems Scimitar bellcranks have built have made I/ aircraft plywood rim pieces /16 plywood makes device very strong easy fabricate special tools finished weight about ounce would like try make systems have put together detailed set instructions diagrams can use assemble install Ill glad mail copy you will send check amount $375 cover cost photocopies postage etc instructions include chart covers sizes applications would like custom-design system have written computer program runs under DOS Basic will allow cost 3/2-inch diskette $350 Write 325 Jennings Street Endicott NY 137604018 T POINT BELLCRANK DIAMETER BIAS BIAS ANGLE ANGLE 0 UP, HOLE DOWN HOLE 60 Model Aviation
Edition: Model Aviation - 1994/10
Page Numbers: 57, 59, 60
ne aspect control line models has always problem control system builder striving maneuverability often too sensitive allow airplane easily controlled other hand builder trying produce plane stable easy handle will probably find model lacks sensitivity An article Pro-Stunt News stated beginners try use control system too sensitive abilities suggested control system configured give reduced response thus giving model smoother control good idea flier will probably find airplane will lack necessary sensitivity his/her flying ability increases will forced build another airplane sensitive control system portions control line flight control system really doesnt have generate much control surface movement produce desired maneuver Precision Aerobatics model instance probably has three flight modes level flight round maneuvers square corners model maintain rock-solid level flight pilot probably has adjust control surfaces two tenths degree plane travels around circle difficult best usually results plane hunting slowly drifting up down goes around Some builders attempt compensate building some slop elevator linkage allows plane controlled flaps level flight larger movements control handle allow elevators come play Another method make elevators thinner stabilizer keeps partially out airstream reduces effect small control movements Both methods can effective will result non-linear control system response Circular maneuvers like loops probably require few degrees control surface deflection easier accomplish October 1994 57 -IeeplnePIn Scimi Authors Cessna Ag-Wagon uses Scimitar control system Largerthan-normal wing cutout allows sideways pushrod movement level flight However making perfectly round maneuver still requires accurate control sensitive touch pilot make round maneuvers easier perform builder can reduce sensitivity control system However will make following maneuver difficult execute Square corners require large abrupt control deflection No problem just pull handle fast can real problem comes want return straight flight path end turn small error repositioning handle will cause model overshoot bobble will result corner less 900 Since have walking sensitivitylcontrollability tightrope number years decided try invent new type control system would give reduced sensitivity needed maintain accurate control giving adequate response ensure good maneuverability result work area device call Scimitar bellcrank gave name because two curved slots remind curved swords carried soldiers guard harems Middle East RESPONSE OF CONVENTIONAL CONTROL SYSTEM DEGREES OF FLAP DEFLECTION 004ososo lo Ao - 10 DEGREES OF - o HANDLE - 00 Rotation - 40 --90 --60 --00 - - 90 FIGURE 2 will interested new bellcrank can help Precision Aerobatics fliers concerned both smooth control quick response Scimitar bellcrank will allow flier maintain good control airplane level flight doing round maneuvers Aerobatics pattern will also give quick response perform square maneuvers Navy Carrier jocks may find will give better control models during phases flight either quick response precise control needed Scale pilots will able perform finely controlled touch-and-gos having good response maneuvers EFFECT OF BIAS ON SCIMITAR PUSHROD RESPONSE % OF PUHSROD MAXIMUM MOVEMENT 10 BIAS NO BIAS -10Sot So So BELLCRANK OTATION A8 -70 40 --90 00 70 --00 90 FIGURE 3 October 1994 59 TOP VIEW SIDE VIEW FIGURE 1 might wish attempt part flight routines Before designing new device decided analyze present control system see what its response would look like plot its curve shown Figure X shape calculated using following parameters Line spacing handle 45 inches Line spacing belicrank 30 inches Pushrod moment bellcrank 10 inch Elevator moment 10 inch As can see response conventional system fairly linear curves ends due fact line spacing handle wider bellcrank slope curve goes through neutral point graph quite steep what makes conventional system sensitive curve Scimitar control system shown Figure X shape basically inverted cosine curve response system around neutral point quite slow allows Scimitar system give smooth control airplane level flight doing round figures As bellcrank rotates further response curve rapidly increases slope gives model quick response needed perform square maneuvers Scimitar bellcrank different conventional type pushrod has two spurs spurs reside two curved slots bellcrank rotated counterclockwise left spur would become active moving pushrod right applying up elevator right spur would move its slot inactive similar action would take place bellcrank rotated clockwise right spur pulling pushrod left applying down elevator left spur moves out its slot pushrod holes placed diameter line bellcrank would lot smooth response neutral too much handle deflection would required perform kind tight flying maneuvers first Scimitar bellcrank designed manner did work well reason desirable bias holes slightly off diameter line bellcrank Adding bias bellcrank improves response neutral point adding too much bias 100 makes system sensitive almost back conventional system again Notice distance center bellcrank left pushrod spur longer distance center right spur unequal spacing necessary because pushrod spurs move sideways bellcrank rotates well forward backward sideways movement subtracts pushing motion up elevator adding pulling movement down elevator Adjusting distances shown figure allows up down travels equal both surfaces achieve desired response curve system necessary use circular shape bellcrank means flexible leadout wires must used little danger wires slipping off bellcrank device because groove leadouts reside /4 inch deep line guides installed wing close bellcrank serve keep wires position pushrod free move its slots flying centrifugal force would probably sufficient keep pushrod its proper place ground might possible pushrod move out position jam its slots unless some method used prevent this reason small keeper spring used keeps pushrod position times since made very thin wire its effect noticeable operating controls Control line pilots know making airplane tailheavy will greatly improve its response also know model will difficult handle due increased sensitivity Because its relatively slow response neutral point Scimitar control system allows model balanced quite tailheavy causing normal controllability problems Scimitar bellcranks have built have made I/ aircraft plywood rim pieces /16 plywood makes device very strong easy fabricate special tools finished weight about ounce would like try make systems have put together detailed set instructions diagrams can use assemble install Ill glad mail copy you will send check amount $375 cover cost photocopies postage etc instructions include chart covers sizes applications would like custom-design system have written computer program runs under DOS Basic will allow cost 3/2-inch diskette $350 Write 325 Jennings Street Endicott NY 137604018 T POINT BELLCRANK DIAMETER BIAS BIAS ANGLE ANGLE 0 UP, HOLE DOWN HOLE 60 Model Aviation