Let ei7olk About Brad Powers Deoin does airplane behave does What can make model fly better efficiently very large subjects dont expect answers fell swoop author makes beginning will followed articles irregular schedule. little mumbo-jumbo possible AFTER YEAR OR SO building flying models modelers begin de velop healthy curiosity about principles underlie successful designs Un fortunately clear accurate digestible information about aerodynamics other aspects airplane design dif ficult find example have several books subject yet half really useful others written esoteric fashion prima donnas seem interested displaying fa cility differential equations down-to-earth discussions might en lighten reader believe no idea human knowledge cannot ex plained bright 12-year-old can un derstand presented simple forth right manner As pointed out January 1978 MA article About Size models full-scale counterparts really brothers under skin Principles apply full-scale airplanes equally applicable models design airplanes buildings type writers violins dog collars generally volves three things First needs clear understanding problem solved have understanding usually halfway towards solution Second its necessary have fund knowledge physical other principles drawn upon order create good workable design Often knowing what cannot done important knowing what can future articles will try point out some principles Finally salt sensitive good taste sometimes call artistic ability whei generously sprinkled can make difference between something ordinary something brilliant However so-called artistic ability end itself Art alone can produce pretty nonsense logic alone often produces mediocrity nice blend engineering esthetics can produce airplanes like French Mirage Concorde just much works art Michaelangelos Pieta Picassos Guernica time time will try cover some essentials such things aero dynamics structure layout lofting ths fallacies also ould en able budding designers work purposefully intelligently Quarter Scale model representing sizable expenditure both time dollars meets disaster sad indeed particularly problem poor choice CC location flutter some other cause could have forseen avoided 20 multiple-choice questions El Lets start reviewing what already know checking answers believe rights ones nish article I Tracking directional stability ground taxiing taking off best main wheels a Set parallel another b Toed-in slightly c Toed-out slightly 2 The tendency ground loop left especially tail-draggers due a P-factor b Torque 3 There no such thing a Torque st P-factor Fig TOE ig- K IN V K DL 4B odel Aviation Toein improves ground handling taildrag gers takeoffs such has drag moments explained text referenced Fig 1 Photo Nosen Jenny underside shows recommended toein though natural perspective view tends make look has toe-in really does b P-factor t torque 4 On twin-engine designs counterrota tion propellers a Desirable b Undesirable 5 Successful climb-out after takeoff due a Excess power available b Up elevator c Lots wind 6 On Free Flight models use pen dulums hooked-up activate ailer ons will a Guarantee automatic recovery bank thus assuring straight level flight b Guarantee spiral dive dis aster 7 A well-designed properly-trimed airplane wants a Fly straight level b Fly constant speed rela tive wind c Fly circle 8 A biplane a More efficient monoplane having same wing area b Less efficient monoplane having same wing area 9 Longitudinal stability tendency maintain level flight depends a Downthrust b CG location c Elevator area 10 Lateral stability involves a Dihedral low-wing designs straight wings b Dihedral designs 11 A fuselage itself tail a Is directionally unstable b Is directionally stable its center lateral area reasonably well aft CG c Wants fly sideways 12 Spiral dives caused a Inadequate fin area b Excessive fin area c Inadequate dihedral 13 Dutch Roll caused a Inadequate fin area Ascending blade small_angle / /_______ assumed airflow pattern Descending blade large angle actual flow pattern / Fig3 way -Torque b Excessive dihedral c Gyroscopic effects 14 Lift generated airfoil because a A mass air deflected down ward b There negative pressure over straight level flight upper surface positive pres sure over lower surface Continued page 150 b straight banked flight C TURN ailerons reverse Fig 4 centr u aa force Fig 2 ~P1 factor Pendulum control Free Flight fine model straight flight turn centrifugal force upsets apple cart October 1983 55 NOW PRODUCED IN THE US ANOTHER GIANT FROM J-5 tough TORNADO 4 feet speed stability TORNADO loves rough water handling best time paint clear air clean just little damp usually no wind plane has whole day dry before come back fondle After drying day clear coat just about bulletproof Go ahead put radio engine silicone wing saddle fly thing have lots questions about go about fading colors Ill take some time go over color-fading techniques Fading probably easiest way striking paint jobbut can also create total mess painters try fade colors too far away other spectrum come out looking like forgot piece masking tape tf going try fading colors should use shades close another Dark/light same color works best colors next another color wheel Always shoot colors together little drying time possible Always fade lightest color over dark always hold airbrush overspray goes back color spraying Again biggest secret fading know ing quit hope series articles has given some points painting did know before way way paint has successful thanks Gary MePike tips finishing Pylon Racer See next month Bill Hager 706 Glen Haven Dr Conroe TX 77302 RC Helicopters/Jolly Continued page 53 timately land Long Beach Convention Center Model Aviation carried story August 1980 issue might want particulars third picture Master Ernie Huber hovering Kavan Jet Ranger verted audiences past MACS show love watch someone Ernies talent fly gives rest us something shoot know can have lot fun articles participate Unlike other editors may have ended columns saying Please send information can have something present month Ill put slightly different way Id like send pictures information might have something column dont youll have listen month because will have column blank space used So until next time keep landing rotor blades up Larry Jolly 5501 W Como Santa Ana CA 92703 Airplane Design/Powers Continued paoe 55 15 The weight power speed etc Scale model have real relationship weight power speed etc full-scale prototype a True b False 16The equation lift LCLqS a This abstruse formula no practical value b A half-hours study equa tion will give modeler very useful tool use designing own models 17 Swept highly-tapered wings should have a Washout b Washin 18 Reynolds Number has a Size b Speed c Viscosity d Density e Drag 19 In level flight horizontal tail nor mally carries a An up load lift aft portion airplane b A down load keep nose up c No load because stabilizers have zero incidence 20 On full-size airplanes wing set some angle incidence yet models have wing set zero incidence a Therefore incidence neces sary b If both wing stabilizer set zero incidence airplane will fly up elevator Answers Discussion b tail-dragger arrangement herently unstable because main wheels ahead CG Tail wheels skids provide degree stability very effective because very lightly loaded up off ground almost immediately takeoff main wheels should toed-in As shown Fig airplane begins yaw usually left because propeller torque drag left wheel combines greater moment arm does right wheel its smaller arm B thus producing net mo ment tending increase yaw left cause ground loop toeing-in wheels drag left wheel reduced right wheel increased has effect increasing favorable restoring moment right wheel decreasing adverse moment left wheel can seen under no circumstances should main wheels ever toed-out 2bTorque Propeller torque can con siderable low speed loads up left wheel unloads right wheel causing airplane want turn left should countered application right rud der well toe-in mentioned above Ap plication ailerons counter torque takeoff can induce stall snap roll future article 3b no such thing P-factor described difference angle attack between ascending left pro peller blade descending right blade line flight high angles attack near stall same thrust line prop shown Fig 2 As shown Fig 3 propeller spinning moderately fast tends equalize flow pressure across its diameter disparity angle attack between ascending descending blades equal ized small imbalance between lift blade compared other can cause destructive vibration fixed-pitch propeller 150 Model Aviation Mahogany Plywood Boat Kit Designed Industrial Quadra other 2 cycle engines S 1795 KIT & DRIVE TRAIN $14950 Super offshore Deep V KIT DRIVE TRAIN & ENGINE $26950 Shipping charges included US Canada J- S ENTERPRISES 256 Schuman Dr Newmarket Alabama 35761 Phone 1 -205-852-2566 PO Box 82 Belmont Ontario NOL i Ba Phone 151 9-644-0375 FULL5iZE PLANS Heliboy looking real hard 30 miles open water between sit ting Catalina Island will ul produces maximum torque airplane rest moving very slowly takeoff stall high-speed flight propeller operating its best L/D rpm increases drag torque its minimum propeller unloads say case Helicopters rpm low line flight close rotor disc disparity blade angle between advancing receding blades becomes factor contend same thing P-factor torque future article 4a Torque additive two engines turning same direction torque will twice great produced engine other hand rotation re versed engines torque cancels out airplane free its effects rotation arranged pro pellers swing up out respect fuselage spanwise lift distribution enhanced asymmetry disappears 5a Climb result application power sufficient excess power applying elevator can slow air plane down cause stall 6b A pendulum will work fine long straight flight maintained shown Figs 4a 4b since wants hang down under condition Sooner later relative wind will change initiate turn does centrifugal force will throw pendulum away center turn cause irreversible spiral dive shown Fig 4c 7b An airplane wants fly angle attack speed trimmed horizontal tail also wants turn relative wind 8b A biplane inherently less efficient monoplane because mutual inter ference pressures between wings unfavorable upper wing loses positive pressure its underside lower wing gains pressure over its upper surface 9b Longitudinal stability function CG location CG must always lie ward neutral point See April 1980 MA Lets Talk About CG 10a Lateral stability largely provided dihedral low-wing monoplanes straight unswept wings High-wing monoplanes have effective dihedral due high placement wing little no geometric dihedral required Swept wings Delta wings also have effective di hederal due sweep leading edge fact some highly-swept wings require negative dihedral anhedral placed high fuselage British Har rier II a&c fuselage must have tail Otherwise does indeed want set itself perpendicular airstream fly side ways 12b&c Spiral dives caused cx cessive fin area coupled insufficient di hedral will go length future article 13a&b Dutch roll caused sufficient fin area together excessive dihedral small fin allows fuselage yaw dihedral overcompensates cause lateral oscillations 14a&b mass air accelerated downward reacts produce upward force called litt curved path air stream over wing manifests lift pro duced form increased velocity lower pressure over upper surface decrease velocity increased pressure over lower surface thus distributing lift over wing ISa True precise relationships between large small things having same configuration means operation pointed out beginning article 16b use Lift Equation will subject next article nearly formidable looks useful understanding wing area weight speed etc interrelated 17a Washout together increase camber wing tips desirable prevent tip stall 18all Reynolds Number has things See Lets Talk About Reynolds Number February 1979 MA 19b stable airplane has its CG forward neutral point center total lift whole airplane Therefore must down load horizontal tail keep nose up has effect moving net lift forward CG 2Gb maximum range real air plane wing incidence normally set angle Max L/D airfoils about three degrees downwash wing usually adequate trim airplane level flight cruising speed producing down-load tail tail set zero incidence Pattern models having symmetrical airfoils desired have no sur prises flying upside down something said setting both wing tail zero degrees done airplane will fly however unless some up-elevator applied trim wing positive angle attack Thus airplane can maintain level flight fuselage attitude slight climb would suggest maybe Pat tern jobs should designed flaps can deflected either up down provide positive incidence form camber either normal inverted flight Maybe already havent progressed Pattern flying yet well did score Dont hesitate write have questions polite com ments Bradford W Powers 5470 Castle Hills Dr San Diego CA 92109 Annes Plane/McNally Continued paoe 58 tually impossible younger modelers avoid gluing themselves Industrial expe rience epoxy seems indicate everyone will become allergic epoxy enough exposure Avoiding inhaling fumes skin contact allows safe use Bill Effinger suggests Plan N Pattern SetsrM offer really beautiful Full Size Plan Drawings Material List Parts Drawing fabricate superb replica design Prom Hobby Dealer TESTIMONIALS have seen two plans make other com panies plans look sick plans make building scratch like kit building RMacL. New York SPAD C-XIII World War 13 31 Engines79% WIngspan 2120 Sq new design offering makes beautiful R/G replica WW-l era 2120 Sq area its big aircraft capable flyer captures imagination Plan N Pattern Set #RCQS-U @ $2495 rldWarl SE-5A Quarter Scale RIC Far 78 22 Engines 80% Wingspan Sq Inches Area Plan N Pattern Set #RCQS-7 @ $2495 FOKKER TRIPLANE DR-I Giant 1/4 Scale R/C Design WW-l 78 160 Cu Engines 72 Wingspan Triplane Sq Area Plan N Pattern Set #RCQS-6 @ $2495 otter beautifully prepared Plan Designs best Full Size Layouts Parts Drawings Bill ot Materials data create own replica Saves substantial amounts over full kit costs Prices Complete Plans Sub Assembly De tailed Parts List Add $200 tor Mailing Tube SEND FOR BROCHURE ahead crowd New Brochure showing new designs tor 1983-84 Send $100 refundable first order October 1983 151 -FGLOW ireb PLUGS NEW IMPROVED High Performance Glow Element e Blow Proof Seal Six Types 3 Heat Ranges Longer Life Only $129 SwansonAssociates PO Box 151~ Since 7948 Wayne NJ 07470
Edition: Model Aviation - 1983/10
Page Numbers: 54, 55, 150, 151
Let ei7olk About Brad Powers Deoin does airplane behave does What can make model fly better efficiently very large subjects dont expect answers fell swoop author makes beginning will followed articles irregular schedule. little mumbo-jumbo possible AFTER YEAR OR SO building flying models modelers begin de velop healthy curiosity about principles underlie successful designs Un fortunately clear accurate digestible information about aerodynamics other aspects airplane design dif ficult find example have several books subject yet half really useful others written esoteric fashion prima donnas seem interested displaying fa cility differential equations down-to-earth discussions might en lighten reader believe no idea human knowledge cannot ex plained bright 12-year-old can un derstand presented simple forth right manner As pointed out January 1978 MA article About Size models full-scale counterparts really brothers under skin Principles apply full-scale airplanes equally applicable models design airplanes buildings type writers violins dog collars generally volves three things First needs clear understanding problem solved have understanding usually halfway towards solution Second its necessary have fund knowledge physical other principles drawn upon order create good workable design Often knowing what cannot done important knowing what can future articles will try point out some principles Finally salt sensitive good taste sometimes call artistic ability whei generously sprinkled can make difference between something ordinary something brilliant However so-called artistic ability end itself Art alone can produce pretty nonsense logic alone often produces mediocrity nice blend engineering esthetics can produce airplanes like French Mirage Concorde just much works art Michaelangelos Pieta Picassos Guernica time time will try cover some essentials such things aero dynamics structure layout lofting ths fallacies also ould en able budding designers work purposefully intelligently Quarter Scale model representing sizable expenditure both time dollars meets disaster sad indeed particularly problem poor choice CC location flutter some other cause could have forseen avoided 20 multiple-choice questions El Lets start reviewing what already know checking answers believe rights ones nish article I Tracking directional stability ground taxiing taking off best main wheels a Set parallel another b Toed-in slightly c Toed-out slightly 2 The tendency ground loop left especially tail-draggers due a P-factor b Torque 3 There no such thing a Torque st P-factor Fig TOE ig- K IN V K DL 4B odel Aviation Toein improves ground handling taildrag gers takeoffs such has drag moments explained text referenced Fig 1 Photo Nosen Jenny underside shows recommended toein though natural perspective view tends make look has toe-in really does b P-factor t torque 4 On twin-engine designs counterrota tion propellers a Desirable b Undesirable 5 Successful climb-out after takeoff due a Excess power available b Up elevator c Lots wind 6 On Free Flight models use pen dulums hooked-up activate ailer ons will a Guarantee automatic recovery bank thus assuring straight level flight b Guarantee spiral dive dis aster 7 A well-designed properly-trimed airplane wants a Fly straight level b Fly constant speed rela tive wind c Fly circle 8 A biplane a More efficient monoplane having same wing area b Less efficient monoplane having same wing area 9 Longitudinal stability tendency maintain level flight depends a Downthrust b CG location c Elevator area 10 Lateral stability involves a Dihedral low-wing designs straight wings b Dihedral designs 11 A fuselage itself tail a Is directionally unstable b Is directionally stable its center lateral area reasonably well aft CG c Wants fly sideways 12 Spiral dives caused a Inadequate fin area b Excessive fin area c Inadequate dihedral 13 Dutch Roll caused a Inadequate fin area Ascending blade small_angle / /_______ assumed airflow pattern Descending blade large angle actual flow pattern / Fig3 way -Torque b Excessive dihedral c Gyroscopic effects 14 Lift generated airfoil because a A mass air deflected down ward b There negative pressure over straight level flight upper surface positive pres sure over lower surface Continued page 150 b straight banked flight C TURN ailerons reverse Fig 4 centr u aa force Fig 2 ~P1 factor Pendulum control Free Flight fine model straight flight turn centrifugal force upsets apple cart October 1983 55 NOW PRODUCED IN THE US ANOTHER GIANT FROM J-5 tough TORNADO 4 feet speed stability TORNADO loves rough water handling best time paint clear air clean just little damp usually no wind plane has whole day dry before come back fondle After drying day clear coat just about bulletproof Go ahead put radio engine silicone wing saddle fly thing have lots questions about go about fading colors Ill take some time go over color-fading techniques Fading probably easiest way striking paint jobbut can also create total mess painters try fade colors too far away other spectrum come out looking like forgot piece masking tape tf going try fading colors should use shades close another Dark/light same color works best colors next another color wheel Always shoot colors together little drying time possible Always fade lightest color over dark always hold airbrush overspray goes back color spraying Again biggest secret fading know ing quit hope series articles has given some points painting did know before way way paint has successful thanks Gary MePike tips finishing Pylon Racer See next month Bill Hager 706 Glen Haven Dr Conroe TX 77302 RC Helicopters/Jolly Continued page 53 timately land Long Beach Convention Center Model Aviation carried story August 1980 issue might want particulars third picture Master Ernie Huber hovering Kavan Jet Ranger verted audiences past MACS show love watch someone Ernies talent fly gives rest us something shoot know can have lot fun articles participate Unlike other editors may have ended columns saying Please send information can have something present month Ill put slightly different way Id like send pictures information might have something column dont youll have listen month because will have column blank space used So until next time keep landing rotor blades up Larry Jolly 5501 W Como Santa Ana CA 92703 Airplane Design/Powers Continued paoe 55 15 The weight power speed etc Scale model have real relationship weight power speed etc full-scale prototype a True b False 16The equation lift LCLqS a This abstruse formula no practical value b A half-hours study equa tion will give modeler very useful tool use designing own models 17 Swept highly-tapered wings should have a Washout b Washin 18 Reynolds Number has a Size b Speed c Viscosity d Density e Drag 19 In level flight horizontal tail nor mally carries a An up load lift aft portion airplane b A down load keep nose up c No load because stabilizers have zero incidence 20 On full-size airplanes wing set some angle incidence yet models have wing set zero incidence a Therefore incidence neces sary b If both wing stabilizer set zero incidence airplane will fly up elevator Answers Discussion b tail-dragger arrangement herently unstable because main wheels ahead CG Tail wheels skids provide degree stability very effective because very lightly loaded up off ground almost immediately takeoff main wheels should toed-in As shown Fig airplane begins yaw usually left because propeller torque drag left wheel combines greater moment arm does right wheel its smaller arm B thus producing net mo ment tending increase yaw left cause ground loop toeing-in wheels drag left wheel reduced right wheel increased has effect increasing favorable restoring moment right wheel decreasing adverse moment left wheel can seen under no circumstances should main wheels ever toed-out 2bTorque Propeller torque can con siderable low speed loads up left wheel unloads right wheel causing airplane want turn left should countered application right rud der well toe-in mentioned above Ap plication ailerons counter torque takeoff can induce stall snap roll future article 3b no such thing P-factor described difference angle attack between ascending left pro peller blade descending right blade line flight high angles attack near stall same thrust line prop shown Fig 2 As shown Fig 3 propeller spinning moderately fast tends equalize flow pressure across its diameter disparity angle attack between ascending descending blades equal ized small imbalance between lift blade compared other can cause destructive vibration fixed-pitch propeller 150 Model Aviation Mahogany Plywood Boat Kit Designed Industrial Quadra other 2 cycle engines S 1795 KIT & DRIVE TRAIN $14950 Super offshore Deep V KIT DRIVE TRAIN & ENGINE $26950 Shipping charges included US Canada J- S ENTERPRISES 256 Schuman Dr Newmarket Alabama 35761 Phone 1 -205-852-2566 PO Box 82 Belmont Ontario NOL i Ba Phone 151 9-644-0375 FULL5iZE PLANS Heliboy looking real hard 30 miles open water between sit ting Catalina Island will ul produces maximum torque airplane rest moving very slowly takeoff stall high-speed flight propeller operating its best L/D rpm increases drag torque its minimum propeller unloads say case Helicopters rpm low line flight close rotor disc disparity blade angle between advancing receding blades becomes factor contend same thing P-factor torque future article 4a Torque additive two engines turning same direction torque will twice great produced engine other hand rotation re versed engines torque cancels out airplane free its effects rotation arranged pro pellers swing up out respect fuselage spanwise lift distribution enhanced asymmetry disappears 5a Climb result application power sufficient excess power applying elevator can slow air plane down cause stall 6b A pendulum will work fine long straight flight maintained shown Figs 4a 4b since wants hang down under condition Sooner later relative wind will change initiate turn does centrifugal force will throw pendulum away center turn cause irreversible spiral dive shown Fig 4c 7b An airplane wants fly angle attack speed trimmed horizontal tail also wants turn relative wind 8b A biplane inherently less efficient monoplane because mutual inter ference pressures between wings unfavorable upper wing loses positive pressure its underside lower wing gains pressure over its upper surface 9b Longitudinal stability function CG location CG must always lie ward neutral point See April 1980 MA Lets Talk About CG 10a Lateral stability largely provided dihedral low-wing monoplanes straight unswept wings High-wing monoplanes have effective dihedral due high placement wing little no geometric dihedral required Swept wings Delta wings also have effective di hederal due sweep leading edge fact some highly-swept wings require negative dihedral anhedral placed high fuselage British Har rier II a&c fuselage must have tail Otherwise does indeed want set itself perpendicular airstream fly side ways 12b&c Spiral dives caused cx cessive fin area coupled insufficient di hedral will go length future article 13a&b Dutch roll caused sufficient fin area together excessive dihedral small fin allows fuselage yaw dihedral overcompensates cause lateral oscillations 14a&b mass air accelerated downward reacts produce upward force called litt curved path air stream over wing manifests lift pro duced form increased velocity lower pressure over upper surface decrease velocity increased pressure over lower surface thus distributing lift over wing ISa True precise relationships between large small things having same configuration means operation pointed out beginning article 16b use Lift Equation will subject next article nearly formidable looks useful understanding wing area weight speed etc interrelated 17a Washout together increase camber wing tips desirable prevent tip stall 18all Reynolds Number has things See Lets Talk About Reynolds Number February 1979 MA 19b stable airplane has its CG forward neutral point center total lift whole airplane Therefore must down load horizontal tail keep nose up has effect moving net lift forward CG 2Gb maximum range real air plane wing incidence normally set angle Max L/D airfoils about three degrees downwash wing usually adequate trim airplane level flight cruising speed producing down-load tail tail set zero incidence Pattern models having symmetrical airfoils desired have no sur prises flying upside down something said setting both wing tail zero degrees done airplane will fly however unless some up-elevator applied trim wing positive angle attack Thus airplane can maintain level flight fuselage attitude slight climb would suggest maybe Pat tern jobs should designed flaps can deflected either up down provide positive incidence form camber either normal inverted flight Maybe already havent progressed Pattern flying yet well did score Dont hesitate write have questions polite com ments Bradford W Powers 5470 Castle Hills Dr San Diego CA 92109 Annes Plane/McNally Continued paoe 58 tually impossible younger modelers avoid gluing themselves Industrial expe rience epoxy seems indicate everyone will become allergic epoxy enough exposure Avoiding inhaling fumes skin contact allows safe use Bill Effinger suggests Plan N Pattern SetsrM offer really beautiful Full Size Plan Drawings Material List Parts Drawing fabricate superb replica design Prom Hobby Dealer TESTIMONIALS have seen two plans make other com panies plans look sick plans make building scratch like kit building RMacL. New York SPAD C-XIII World War 13 31 Engines79% WIngspan 2120 Sq new design offering makes beautiful R/G replica WW-l era 2120 Sq area its big aircraft capable flyer captures imagination Plan N Pattern Set #RCQS-U @ $2495 rldWarl SE-5A Quarter Scale RIC Far 78 22 Engines 80% Wingspan Sq Inches Area Plan N Pattern Set #RCQS-7 @ $2495 FOKKER TRIPLANE DR-I Giant 1/4 Scale R/C Design WW-l 78 160 Cu Engines 72 Wingspan Triplane Sq Area Plan N Pattern Set #RCQS-6 @ $2495 otter beautifully prepared Plan Designs best Full Size Layouts Parts Drawings Bill ot Materials data create own replica Saves substantial amounts over full kit costs Prices Complete Plans Sub Assembly De tailed Parts List Add $200 tor Mailing Tube SEND FOR BROCHURE ahead crowd New Brochure showing new designs tor 1983-84 Send $100 refundable first order October 1983 151 -FGLOW ireb PLUGS NEW IMPROVED High Performance Glow Element e Blow Proof Seal Six Types 3 Heat Ranges Longer Life Only $129 SwansonAssociates PO Box 151~ Since 7948 Wayne NJ 07470
Edition: Model Aviation - 1983/10
Page Numbers: 54, 55, 150, 151
Let ei7olk About Brad Powers Deoin does airplane behave does What can make model fly better efficiently very large subjects dont expect answers fell swoop author makes beginning will followed articles irregular schedule. little mumbo-jumbo possible AFTER YEAR OR SO building flying models modelers begin de velop healthy curiosity about principles underlie successful designs Un fortunately clear accurate digestible information about aerodynamics other aspects airplane design dif ficult find example have several books subject yet half really useful others written esoteric fashion prima donnas seem interested displaying fa cility differential equations down-to-earth discussions might en lighten reader believe no idea human knowledge cannot ex plained bright 12-year-old can un derstand presented simple forth right manner As pointed out January 1978 MA article About Size models full-scale counterparts really brothers under skin Principles apply full-scale airplanes equally applicable models design airplanes buildings type writers violins dog collars generally volves three things First needs clear understanding problem solved have understanding usually halfway towards solution Second its necessary have fund knowledge physical other principles drawn upon order create good workable design Often knowing what cannot done important knowing what can future articles will try point out some principles Finally salt sensitive good taste sometimes call artistic ability whei generously sprinkled can make difference between something ordinary something brilliant However so-called artistic ability end itself Art alone can produce pretty nonsense logic alone often produces mediocrity nice blend engineering esthetics can produce airplanes like French Mirage Concorde just much works art Michaelangelos Pieta Picassos Guernica time time will try cover some essentials such things aero dynamics structure layout lofting ths fallacies also ould en able budding designers work purposefully intelligently Quarter Scale model representing sizable expenditure both time dollars meets disaster sad indeed particularly problem poor choice CC location flutter some other cause could have forseen avoided 20 multiple-choice questions El Lets start reviewing what already know checking answers believe rights ones nish article I Tracking directional stability ground taxiing taking off best main wheels a Set parallel another b Toed-in slightly c Toed-out slightly 2 The tendency ground loop left especially tail-draggers due a P-factor b Torque 3 There no such thing a Torque st P-factor Fig TOE ig- K IN V K DL 4B odel Aviation Toein improves ground handling taildrag gers takeoffs such has drag moments explained text referenced Fig 1 Photo Nosen Jenny underside shows recommended toein though natural perspective view tends make look has toe-in really does b P-factor t torque 4 On twin-engine designs counterrota tion propellers a Desirable b Undesirable 5 Successful climb-out after takeoff due a Excess power available b Up elevator c Lots wind 6 On Free Flight models use pen dulums hooked-up activate ailer ons will a Guarantee automatic recovery bank thus assuring straight level flight b Guarantee spiral dive dis aster 7 A well-designed properly-trimed airplane wants a Fly straight level b Fly constant speed rela tive wind c Fly circle 8 A biplane a More efficient monoplane having same wing area b Less efficient monoplane having same wing area 9 Longitudinal stability tendency maintain level flight depends a Downthrust b CG location c Elevator area 10 Lateral stability involves a Dihedral low-wing designs straight wings b Dihedral designs 11 A fuselage itself tail a Is directionally unstable b Is directionally stable its center lateral area reasonably well aft CG c Wants fly sideways 12 Spiral dives caused a Inadequate fin area b Excessive fin area c Inadequate dihedral 13 Dutch Roll caused a Inadequate fin area Ascending blade small_angle / /_______ assumed airflow pattern Descending blade large angle actual flow pattern / Fig3 way -Torque b Excessive dihedral c Gyroscopic effects 14 Lift generated airfoil because a A mass air deflected down ward b There negative pressure over straight level flight upper surface positive pres sure over lower surface Continued page 150 b straight banked flight C TURN ailerons reverse Fig 4 centr u aa force Fig 2 ~P1 factor Pendulum control Free Flight fine model straight flight turn centrifugal force upsets apple cart October 1983 55 NOW PRODUCED IN THE US ANOTHER GIANT FROM J-5 tough TORNADO 4 feet speed stability TORNADO loves rough water handling best time paint clear air clean just little damp usually no wind plane has whole day dry before come back fondle After drying day clear coat just about bulletproof Go ahead put radio engine silicone wing saddle fly thing have lots questions about go about fading colors Ill take some time go over color-fading techniques Fading probably easiest way striking paint jobbut can also create total mess painters try fade colors too far away other spectrum come out looking like forgot piece masking tape tf going try fading colors should use shades close another Dark/light same color works best colors next another color wheel Always shoot colors together little drying time possible Always fade lightest color over dark always hold airbrush overspray goes back color spraying Again biggest secret fading know ing quit hope series articles has given some points painting did know before way way paint has successful thanks Gary MePike tips finishing Pylon Racer See next month Bill Hager 706 Glen Haven Dr Conroe TX 77302 RC Helicopters/Jolly Continued page 53 timately land Long Beach Convention Center Model Aviation carried story August 1980 issue might want particulars third picture Master Ernie Huber hovering Kavan Jet Ranger verted audiences past MACS show love watch someone Ernies talent fly gives rest us something shoot know can have lot fun articles participate Unlike other editors may have ended columns saying Please send information can have something present month Ill put slightly different way Id like send pictures information might have something column dont youll have listen month because will have column blank space used So until next time keep landing rotor blades up Larry Jolly 5501 W Como Santa Ana CA 92703 Airplane Design/Powers Continued paoe 55 15 The weight power speed etc Scale model have real relationship weight power speed etc full-scale prototype a True b False 16The equation lift LCLqS a This abstruse formula no practical value b A half-hours study equa tion will give modeler very useful tool use designing own models 17 Swept highly-tapered wings should have a Washout b Washin 18 Reynolds Number has a Size b Speed c Viscosity d Density e Drag 19 In level flight horizontal tail nor mally carries a An up load lift aft portion airplane b A down load keep nose up c No load because stabilizers have zero incidence 20 On full-size airplanes wing set some angle incidence yet models have wing set zero incidence a Therefore incidence neces sary b If both wing stabilizer set zero incidence airplane will fly up elevator Answers Discussion b tail-dragger arrangement herently unstable because main wheels ahead CG Tail wheels skids provide degree stability very effective because very lightly loaded up off ground almost immediately takeoff main wheels should toed-in As shown Fig airplane begins yaw usually left because propeller torque drag left wheel combines greater moment arm does right wheel its smaller arm B thus producing net mo ment tending increase yaw left cause ground loop toeing-in wheels drag left wheel reduced right wheel increased has effect increasing favorable restoring moment right wheel decreasing adverse moment left wheel can seen under no circumstances should main wheels ever toed-out 2bTorque Propeller torque can con siderable low speed loads up left wheel unloads right wheel causing airplane want turn left should countered application right rud der well toe-in mentioned above Ap plication ailerons counter torque takeoff can induce stall snap roll future article 3b no such thing P-factor described difference angle attack between ascending left pro peller blade descending right blade line flight high angles attack near stall same thrust line prop shown Fig 2 As shown Fig 3 propeller spinning moderately fast tends equalize flow pressure across its diameter disparity angle attack between ascending descending blades equal ized small imbalance between lift blade compared other can cause destructive vibration fixed-pitch propeller 150 Model Aviation Mahogany Plywood Boat Kit Designed Industrial Quadra other 2 cycle engines S 1795 KIT & DRIVE TRAIN $14950 Super offshore Deep V KIT DRIVE TRAIN & ENGINE $26950 Shipping charges included US Canada J- S ENTERPRISES 256 Schuman Dr Newmarket Alabama 35761 Phone 1 -205-852-2566 PO Box 82 Belmont Ontario NOL i Ba Phone 151 9-644-0375 FULL5iZE PLANS Heliboy looking real hard 30 miles open water between sit ting Catalina Island will ul produces maximum torque airplane rest moving very slowly takeoff stall high-speed flight propeller operating its best L/D rpm increases drag torque its minimum propeller unloads say case Helicopters rpm low line flight close rotor disc disparity blade angle between advancing receding blades becomes factor contend same thing P-factor torque future article 4a Torque additive two engines turning same direction torque will twice great produced engine other hand rotation re versed engines torque cancels out airplane free its effects rotation arranged pro pellers swing up out respect fuselage spanwise lift distribution enhanced asymmetry disappears 5a Climb result application power sufficient excess power applying elevator can slow air plane down cause stall 6b A pendulum will work fine long straight flight maintained shown Figs 4a 4b since wants hang down under condition Sooner later relative wind will change initiate turn does centrifugal force will throw pendulum away center turn cause irreversible spiral dive shown Fig 4c 7b An airplane wants fly angle attack speed trimmed horizontal tail also wants turn relative wind 8b A biplane inherently less efficient monoplane because mutual inter ference pressures between wings unfavorable upper wing loses positive pressure its underside lower wing gains pressure over its upper surface 9b Longitudinal stability function CG location CG must always lie ward neutral point See April 1980 MA Lets Talk About CG 10a Lateral stability largely provided dihedral low-wing monoplanes straight unswept wings High-wing monoplanes have effective dihedral due high placement wing little no geometric dihedral required Swept wings Delta wings also have effective di hederal due sweep leading edge fact some highly-swept wings require negative dihedral anhedral placed high fuselage British Har rier II a&c fuselage must have tail Otherwise does indeed want set itself perpendicular airstream fly side ways 12b&c Spiral dives caused cx cessive fin area coupled insufficient di hedral will go length future article 13a&b Dutch roll caused sufficient fin area together excessive dihedral small fin allows fuselage yaw dihedral overcompensates cause lateral oscillations 14a&b mass air accelerated downward reacts produce upward force called litt curved path air stream over wing manifests lift pro duced form increased velocity lower pressure over upper surface decrease velocity increased pressure over lower surface thus distributing lift over wing ISa True precise relationships between large small things having same configuration means operation pointed out beginning article 16b use Lift Equation will subject next article nearly formidable looks useful understanding wing area weight speed etc interrelated 17a Washout together increase camber wing tips desirable prevent tip stall 18all Reynolds Number has things See Lets Talk About Reynolds Number February 1979 MA 19b stable airplane has its CG forward neutral point center total lift whole airplane Therefore must down load horizontal tail keep nose up has effect moving net lift forward CG 2Gb maximum range real air plane wing incidence normally set angle Max L/D airfoils about three degrees downwash wing usually adequate trim airplane level flight cruising speed producing down-load tail tail set zero incidence Pattern models having symmetrical airfoils desired have no sur prises flying upside down something said setting both wing tail zero degrees done airplane will fly however unless some up-elevator applied trim wing positive angle attack Thus airplane can maintain level flight fuselage attitude slight climb would suggest maybe Pat tern jobs should designed flaps can deflected either up down provide positive incidence form camber either normal inverted flight Maybe already havent progressed Pattern flying yet well did score Dont hesitate write have questions polite com ments Bradford W Powers 5470 Castle Hills Dr San Diego CA 92109 Annes Plane/McNally Continued paoe 58 tually impossible younger modelers avoid gluing themselves Industrial expe rience epoxy seems indicate everyone will become allergic epoxy enough exposure Avoiding inhaling fumes skin contact allows safe use Bill Effinger suggests Plan N Pattern SetsrM offer really beautiful Full Size Plan Drawings Material List Parts Drawing fabricate superb replica design Prom Hobby Dealer TESTIMONIALS have seen two plans make other com panies plans look sick plans make building scratch like kit building RMacL. New York SPAD C-XIII World War 13 31 Engines79% WIngspan 2120 Sq new design offering makes beautiful R/G replica WW-l era 2120 Sq area its big aircraft capable flyer captures imagination Plan N Pattern Set #RCQS-U @ $2495 rldWarl SE-5A Quarter Scale RIC Far 78 22 Engines 80% Wingspan Sq Inches Area Plan N Pattern Set #RCQS-7 @ $2495 FOKKER TRIPLANE DR-I Giant 1/4 Scale R/C Design WW-l 78 160 Cu Engines 72 Wingspan Triplane Sq Area Plan N Pattern Set #RCQS-6 @ $2495 otter beautifully prepared Plan Designs best Full Size Layouts Parts Drawings Bill ot Materials data create own replica Saves substantial amounts over full kit costs Prices Complete Plans Sub Assembly De tailed Parts List Add $200 tor Mailing Tube SEND FOR BROCHURE ahead crowd New Brochure showing new designs tor 1983-84 Send $100 refundable first order October 1983 151 -FGLOW ireb PLUGS NEW IMPROVED High Performance Glow Element e Blow Proof Seal Six Types 3 Heat Ranges Longer Life Only $129 SwansonAssociates PO Box 151~ Since 7948 Wayne NJ 07470
Edition: Model Aviation - 1983/10
Page Numbers: 54, 55, 150, 151
Let ei7olk About Brad Powers Deoin does airplane behave does What can make model fly better efficiently very large subjects dont expect answers fell swoop author makes beginning will followed articles irregular schedule. little mumbo-jumbo possible AFTER YEAR OR SO building flying models modelers begin de velop healthy curiosity about principles underlie successful designs Un fortunately clear accurate digestible information about aerodynamics other aspects airplane design dif ficult find example have several books subject yet half really useful others written esoteric fashion prima donnas seem interested displaying fa cility differential equations down-to-earth discussions might en lighten reader believe no idea human knowledge cannot ex plained bright 12-year-old can un derstand presented simple forth right manner As pointed out January 1978 MA article About Size models full-scale counterparts really brothers under skin Principles apply full-scale airplanes equally applicable models design airplanes buildings type writers violins dog collars generally volves three things First needs clear understanding problem solved have understanding usually halfway towards solution Second its necessary have fund knowledge physical other principles drawn upon order create good workable design Often knowing what cannot done important knowing what can future articles will try point out some principles Finally salt sensitive good taste sometimes call artistic ability whei generously sprinkled can make difference between something ordinary something brilliant However so-called artistic ability end itself Art alone can produce pretty nonsense logic alone often produces mediocrity nice blend engineering esthetics can produce airplanes like French Mirage Concorde just much works art Michaelangelos Pieta Picassos Guernica time time will try cover some essentials such things aero dynamics structure layout lofting ths fallacies also ould en able budding designers work purposefully intelligently Quarter Scale model representing sizable expenditure both time dollars meets disaster sad indeed particularly problem poor choice CC location flutter some other cause could have forseen avoided 20 multiple-choice questions El Lets start reviewing what already know checking answers believe rights ones nish article I Tracking directional stability ground taxiing taking off best main wheels a Set parallel another b Toed-in slightly c Toed-out slightly 2 The tendency ground loop left especially tail-draggers due a P-factor b Torque 3 There no such thing a Torque st P-factor Fig TOE ig- K IN V K DL 4B odel Aviation Toein improves ground handling taildrag gers takeoffs such has drag moments explained text referenced Fig 1 Photo Nosen Jenny underside shows recommended toein though natural perspective view tends make look has toe-in really does b P-factor t torque 4 On twin-engine designs counterrota tion propellers a Desirable b Undesirable 5 Successful climb-out after takeoff due a Excess power available b Up elevator c Lots wind 6 On Free Flight models use pen dulums hooked-up activate ailer ons will a Guarantee automatic recovery bank thus assuring straight level flight b Guarantee spiral dive dis aster 7 A well-designed properly-trimed airplane wants a Fly straight level b Fly constant speed rela tive wind c Fly circle 8 A biplane a More efficient monoplane having same wing area b Less efficient monoplane having same wing area 9 Longitudinal stability tendency maintain level flight depends a Downthrust b CG location c Elevator area 10 Lateral stability involves a Dihedral low-wing designs straight wings b Dihedral designs 11 A fuselage itself tail a Is directionally unstable b Is directionally stable its center lateral area reasonably well aft CG c Wants fly sideways 12 Spiral dives caused a Inadequate fin area b Excessive fin area c Inadequate dihedral 13 Dutch Roll caused a Inadequate fin area Ascending blade small_angle / /_______ assumed airflow pattern Descending blade large angle actual flow pattern / Fig3 way -Torque b Excessive dihedral c Gyroscopic effects 14 Lift generated airfoil because a A mass air deflected down ward b There negative pressure over straight level flight upper surface positive pres sure over lower surface Continued page 150 b straight banked flight C TURN ailerons reverse Fig 4 centr u aa force Fig 2 ~P1 factor Pendulum control Free Flight fine model straight flight turn centrifugal force upsets apple cart October 1983 55 NOW PRODUCED IN THE US ANOTHER GIANT FROM J-5 tough TORNADO 4 feet speed stability TORNADO loves rough water handling best time paint clear air clean just little damp usually no wind plane has whole day dry before come back fondle After drying day clear coat just about bulletproof Go ahead put radio engine silicone wing saddle fly thing have lots questions about go about fading colors Ill take some time go over color-fading techniques Fading probably easiest way striking paint jobbut can also create total mess painters try fade colors too far away other spectrum come out looking like forgot piece masking tape tf going try fading colors should use shades close another Dark/light same color works best colors next another color wheel Always shoot colors together little drying time possible Always fade lightest color over dark always hold airbrush overspray goes back color spraying Again biggest secret fading know ing quit hope series articles has given some points painting did know before way way paint has successful thanks Gary MePike tips finishing Pylon Racer See next month Bill Hager 706 Glen Haven Dr Conroe TX 77302 RC Helicopters/Jolly Continued page 53 timately land Long Beach Convention Center Model Aviation carried story August 1980 issue might want particulars third picture Master Ernie Huber hovering Kavan Jet Ranger verted audiences past MACS show love watch someone Ernies talent fly gives rest us something shoot know can have lot fun articles participate Unlike other editors may have ended columns saying Please send information can have something present month Ill put slightly different way Id like send pictures information might have something column dont youll have listen month because will have column blank space used So until next time keep landing rotor blades up Larry Jolly 5501 W Como Santa Ana CA 92703 Airplane Design/Powers Continued paoe 55 15 The weight power speed etc Scale model have real relationship weight power speed etc full-scale prototype a True b False 16The equation lift LCLqS a This abstruse formula no practical value b A half-hours study equa tion will give modeler very useful tool use designing own models 17 Swept highly-tapered wings should have a Washout b Washin 18 Reynolds Number has a Size b Speed c Viscosity d Density e Drag 19 In level flight horizontal tail nor mally carries a An up load lift aft portion airplane b A down load keep nose up c No load because stabilizers have zero incidence 20 On full-size airplanes wing set some angle incidence yet models have wing set zero incidence a Therefore incidence neces sary b If both wing stabilizer set zero incidence airplane will fly up elevator Answers Discussion b tail-dragger arrangement herently unstable because main wheels ahead CG Tail wheels skids provide degree stability very effective because very lightly loaded up off ground almost immediately takeoff main wheels should toed-in As shown Fig airplane begins yaw usually left because propeller torque drag left wheel combines greater moment arm does right wheel its smaller arm B thus producing net mo ment tending increase yaw left cause ground loop toeing-in wheels drag left wheel reduced right wheel increased has effect increasing favorable restoring moment right wheel decreasing adverse moment left wheel can seen under no circumstances should main wheels ever toed-out 2bTorque Propeller torque can con siderable low speed loads up left wheel unloads right wheel causing airplane want turn left should countered application right rud der well toe-in mentioned above Ap plication ailerons counter torque takeoff can induce stall snap roll future article 3b no such thing P-factor described difference angle attack between ascending left pro peller blade descending right blade line flight high angles attack near stall same thrust line prop shown Fig 2 As shown Fig 3 propeller spinning moderately fast tends equalize flow pressure across its diameter disparity angle attack between ascending descending blades equal ized small imbalance between lift blade compared other can cause destructive vibration fixed-pitch propeller 150 Model Aviation Mahogany Plywood Boat Kit Designed Industrial Quadra other 2 cycle engines S 1795 KIT & DRIVE TRAIN $14950 Super offshore Deep V KIT DRIVE TRAIN & ENGINE $26950 Shipping charges included US Canada J- S ENTERPRISES 256 Schuman Dr Newmarket Alabama 35761 Phone 1 -205-852-2566 PO Box 82 Belmont Ontario NOL i Ba Phone 151 9-644-0375 FULL5iZE PLANS Heliboy looking real hard 30 miles open water between sit ting Catalina Island will ul produces maximum torque airplane rest moving very slowly takeoff stall high-speed flight propeller operating its best L/D rpm increases drag torque its minimum propeller unloads say case Helicopters rpm low line flight close rotor disc disparity blade angle between advancing receding blades becomes factor contend same thing P-factor torque future article 4a Torque additive two engines turning same direction torque will twice great produced engine other hand rotation re versed engines torque cancels out airplane free its effects rotation arranged pro pellers swing up out respect fuselage spanwise lift distribution enhanced asymmetry disappears 5a Climb result application power sufficient excess power applying elevator can slow air plane down cause stall 6b A pendulum will work fine long straight flight maintained shown Figs 4a 4b since wants hang down under condition Sooner later relative wind will change initiate turn does centrifugal force will throw pendulum away center turn cause irreversible spiral dive shown Fig 4c 7b An airplane wants fly angle attack speed trimmed horizontal tail also wants turn relative wind 8b A biplane inherently less efficient monoplane because mutual inter ference pressures between wings unfavorable upper wing loses positive pressure its underside lower wing gains pressure over its upper surface 9b Longitudinal stability function CG location CG must always lie ward neutral point See April 1980 MA Lets Talk About CG 10a Lateral stability largely provided dihedral low-wing monoplanes straight unswept wings High-wing monoplanes have effective dihedral due high placement wing little no geometric dihedral required Swept wings Delta wings also have effective di hederal due sweep leading edge fact some highly-swept wings require negative dihedral anhedral placed high fuselage British Har rier II a&c fuselage must have tail Otherwise does indeed want set itself perpendicular airstream fly side ways 12b&c Spiral dives caused cx cessive fin area coupled insufficient di hedral will go length future article 13a&b Dutch roll caused sufficient fin area together excessive dihedral small fin allows fuselage yaw dihedral overcompensates cause lateral oscillations 14a&b mass air accelerated downward reacts produce upward force called litt curved path air stream over wing manifests lift pro duced form increased velocity lower pressure over upper surface decrease velocity increased pressure over lower surface thus distributing lift over wing ISa True precise relationships between large small things having same configuration means operation pointed out beginning article 16b use Lift Equation will subject next article nearly formidable looks useful understanding wing area weight speed etc interrelated 17a Washout together increase camber wing tips desirable prevent tip stall 18all Reynolds Number has things See Lets Talk About Reynolds Number February 1979 MA 19b stable airplane has its CG forward neutral point center total lift whole airplane Therefore must down load horizontal tail keep nose up has effect moving net lift forward CG 2Gb maximum range real air plane wing incidence normally set angle Max L/D airfoils about three degrees downwash wing usually adequate trim airplane level flight cruising speed producing down-load tail tail set zero incidence Pattern models having symmetrical airfoils desired have no sur prises flying upside down something said setting both wing tail zero degrees done airplane will fly however unless some up-elevator applied trim wing positive angle attack Thus airplane can maintain level flight fuselage attitude slight climb would suggest maybe Pat tern jobs should designed flaps can deflected either up down provide positive incidence form camber either normal inverted flight Maybe already havent progressed Pattern flying yet well did score Dont hesitate write have questions polite com ments Bradford W Powers 5470 Castle Hills Dr San Diego CA 92109 Annes Plane/McNally Continued paoe 58 tually impossible younger modelers avoid gluing themselves Industrial expe rience epoxy seems indicate everyone will become allergic epoxy enough exposure Avoiding inhaling fumes skin contact allows safe use Bill Effinger suggests Plan N Pattern SetsrM offer really beautiful Full Size Plan Drawings Material List Parts Drawing fabricate superb replica design Prom Hobby Dealer TESTIMONIALS have seen two plans make other com panies plans look sick plans make building scratch like kit building RMacL. New York SPAD C-XIII World War 13 31 Engines79% WIngspan 2120 Sq new design offering makes beautiful R/G replica WW-l era 2120 Sq area its big aircraft capable flyer captures imagination Plan N Pattern Set #RCQS-U @ $2495 rldWarl SE-5A Quarter Scale RIC Far 78 22 Engines 80% Wingspan Sq Inches Area Plan N Pattern Set #RCQS-7 @ $2495 FOKKER TRIPLANE DR-I Giant 1/4 Scale R/C Design WW-l 78 160 Cu Engines 72 Wingspan Triplane Sq Area Plan N Pattern Set #RCQS-6 @ $2495 otter beautifully prepared Plan Designs best Full Size Layouts Parts Drawings Bill ot Materials data create own replica Saves substantial amounts over full kit costs Prices Complete Plans Sub Assembly De tailed Parts List Add $200 tor Mailing Tube SEND FOR BROCHURE ahead crowd New Brochure showing new designs tor 1983-84 Send $100 refundable first order October 1983 151 -FGLOW ireb PLUGS NEW IMPROVED High Performance Glow Element e Blow Proof Seal Six Types 3 Heat Ranges Longer Life Only $129 SwansonAssociates PO Box 151~ Since 7948 Wayne NJ 07470