HELP nature phone call received Stunt flier other day seeking help Precision Aerobatics vexing problems Stunt ship perfect way apparently incurable tendency hunt Now type hunting has nothing red hats cold feet antlers above fireplace mantel No Stunter goes hunting youre apt want shoot plane Hunting frustrating condition wherein ship cannot made settle nice flat groove level flight always climbing just little diving just little condition usually deteriorates wind severe enough may make level flight very exciting maneuver indeed What causes ship hunt Lets quickly exam ine forces acting Stunt ship level flight maintain level flight constant speed thrust must equal drag lift must equal weight order ship climb dive equilibrium must disturbed current discussion lets concentrate lift weight properly trimmed Stunt ship center gravity will slightly forward center lift wing Therefore since lift acts upward gravity downward combination forces will attempt cause ship dive lose planes tail exactly what would happen technical jargon tail horizontal stabilizer describes task tail per forms Its function stabilize wing par ticular attitude also functions change titude alrcraft called upon perform aerobatics tale another time youll pardon pun level flight tendency wing dive counteracted slight amount Up eleva tor almost imperceptible amount since amount lift necessary maintain three- four-pound Stunter level flight tiny percentage lift capability its lightly loaded wing ship therefore stabi lized elevator applying slight amount downward force tail offset opposing downward force aircrafts weight tal lift required wing will now sum weight airplane downward force tail Parenthetically Up elevator also means whereby symmetrically airfoiled Stunt wing produces lift Since contours top bottom wing identical pro duce no differential airflow rates fore no difference pressure above below wing generated necessary such wing always inclined some angle attack produce lift Once state equilibrium achieved ship should truck along nice please until acted upon some force disrupts bal ance force could either aerodynamic mechanical Aerodynamic forces would cause dis ruption equilibrium has achieved exception turbulent air pretty limited Since CL models airspeed continuously altered wind can have significant effect lift severity its effect can altered different states aircraft trim Lets take look occurs equation lift made up roughiy equal parts wing efficiency ie coefficient lift air density angle attack wing fourth component equation airspeed unlike first three factors lift increases square airspeed As fly circular levelflight pattern wind therefore lift will con stantly either increasing decreasing fly out wind As lift increases wind ship will climb vice versa down wind must therefore make continual inputs elevator trim wing new stabilized angle attack will precisely balance lift gravity maintain elusive four- sixfoot elevation strive maintain amount elevator change necessary situation depends large part distance between center-of-gravity center Continued page 159 Mike Ditrich Erie PA loves Steve Wooleys famous Cobra design L sixth hes built Weight 52 oz engine ST 46 Its lovely Kaz Minato has migrated Japan Los Angeles flies original-design Blue Max R Power specially fitted 05 45 FSR/ABC Kaz used engineer OS Hes now working Honda Motorcar R&D 70 Model Aviation Conoi Line Aerobatics Ted Fancher 158 FlyIng Cloud Isle Foster City CA 94404 Spectacular Don Hutchinsons semiscale Stearman Stunter rather small ship 34-in span Veco 19 power Flaps bottom wing reportedly have helped elimi nate mushing square maneuvers compared other biplanes Hutchinson photo Windy Urtnowskis Pro-Stunt Products handmade control handle Delrin bellcrank mentioned Ted June col umn Great-looking products motor pointing forward Flying Check plane balances point indicated plans before going out fly adding clay nose tail correct necessary Preset elevons bent up about /t6 Begin test gliding over some nice thick grass 163 wants glide fast give good solid push launch little adjust ing placement clay amount elevon deflection may neces sary proper trim Charge up motor hand launch gentle push glide trim anywhere near OK 163 should climb out nicely Try varying motors speed see what effects climb thrust line shown moder ate power setting 163 should climb series gentle power stalls somewhere between 75 100 ft cruise come down fast would like model have scalelike steep climb rate add slight amount downthrust motor model capable rise-off-ground flights Placed fairly smooth surface recently graded dirt road will ROG two five feet moder ate power setting might want experiment should possible install flattened tubing vertically wheels will drop off takeoff type flight trim model fly wheels Finishing Paint model very thin coats avoid weight buildup did airbrush spraying mixture nontautening nitrate dope pigment Floquil model train paints mix paint start new bottle Floquil pour off liquid Refill bottle thinner dope using shake mix spraying use mixture part new pigment mix five 10 parts clear dope Sigs Lite Coat works well coat color mixture thinned enough spray about right colors adds little weight used clear Contac shelf paper mask ing out camouflage patterns Flat spray enamels could also used model Make photocopy insignias glue get set ESCI %2-scale de cals Ju-52 did Me-163 has exciting project Flying wings have intrigued years hope too will try out fun excitement building fly ing CL Aerobatics/Fancher Continued page 70 lift nose-heavy ship greater elevator deflection necessary level flight greater change elevator position maintain constantly changing angle attack requirement wind As ihip gets too nose-heavy surprising pilot un able precisely manage input necessary maintain level track vast experience half-vast some peers might amend conventional flapped Stunters will have CG located 16% 18% average chord empty gas tank youve moved CU forward try cure hunting prob lem take out weight start looking else might also want ponder shift CU comes burning large amounts fuel out nose light Stunter might cause ship hunt unacceptably beginning flight settle down towards end CU moves aft can sec classic cures hunting airplane se weight ldom good idea True ship too tail-heavy might very well tough fly level would also have number other significant problems would very twitchy maneuvers would likely light lines flight would also float excessively dur ing glide t light lines difficult contrul glide Another aerodynamic source hunting could having adjustable control line leadOuts too far aft Since CU ship aligns self lead-out position flight can seen under condition Stunter would flying excessively crabbed condition center point lead-outs should almost never aft CU inch-anda-half Ted says ship hunts dead calm air too CU right 16% mean Continued page 162 August 1988 159 AllIMTh IPThThi TING SERVICE QUICK SERVICE OVER 300 ORDINATE SETS ON FILE SEND $200 and SASH long envelope samples list airfoils hand now SEND $500 SASE long plot yonr chord length set samples name anveral airfoils order preference Inclade photo copy shape data possible SEND $1000 PLOT SHAPE CATALOG 300 pIns airfoils 6 inch plots plas historical airfoil information other asefall airfoil data many pages STANDARD PLOTS. nader 10 inches paga Large chords availahle extra cost cost proportional chord length 20 chord twice cost 10 plot CUSTOM PLOTrING AVAILABLE Can modify camher thickness add pieces together can show varions skin thicknesses sop & bottom different TAPERED WING PLOTS $1000 Set ap pbs 50 cents per rib over 10 slightly higher THIS MONTHS HOT PLOTS NACA 0009 Oreat staht EPPLER 193 195 197 RAP 31 32 33 Can show 1/16 thor 1/8th Skin thickness NO EXTRA CHARGE Hot plots Only $100 over 10 $200 TI-lB PTERANODON PRESS nRtcas NEVELN PO BOX 3630 OAKLAND c 5161151630 hinge lines Control surface efficiency affected CL Aerobatics/Fancher by gap between fixed moving portions CL Scale/Boss Continued page 159 surface gap increases sur face deflected direction tightens Continued page 71 its deflected other unequal control response will result Sealing hinge lines elim inates differential also increases con trol effectiveness Doing good idea ship doesnt hunt chord lead-outs nice inch-and-aquarter aft Whats wrong Most hunting problems mechanical ongin can caused misaligned controls sticking control systems andmost common experiencepoorly adjusted control systems usually handle Heres couple easy ones no place competitive Stunter serious sport aerobatic ship sticky control systems cannot make precise input necessary precision flight youve gotta yank get controls move control surfaces should precisely aligned other wing tail stalled centerlines aligned other engines thrust line techni cal terms described zero degrees inci dence MIGHT find necessary some point tweak neutral flaps eleva tors relative another start should precisely neutral simultaneously youve got basics taken care lets take practice flight try diagnose solu tion attempting fly straight level ana lyze very carefully what airplane trying what must counteract its tenden cies likely find upright ship wants either climb dive its own must periodically correct condition invert ship will likely find condition reversed ie ship wanted climb upright wants de scend inverted vice versa may also find allowed climb ship will find some altitude other four six feet perfectly happy groove day long What probably happening hand position holding handle neutral causing controls slightly deflected thereby causing ship climb and/or dive Af ter make input correct situation return natural neutralwhich starts cycle again cure tendency simply shorten proper line handle /16 time until hunt goes away ship wants climb upright shorten Down line etc Other symptoms would support diag nosis would unequal turn rates forego ing problem apt find ship less responsive outside turns Adjusting handles neutral would correct both problems ship doesnt respond corrective procedure consider sealing flap elevator foregoing has helped still some tried true remedies Stunt foildore so some ugly ones involve knives such Some fliers advocate use elevators thinner fixed stab theory must deflect further before causing pitch change Thus flaps will deflected crease decrease lift also having pitch change results elevator deflec flon Some fliers including yours truly build some slop elevator thus allowing some flap movement deflecting elevator much same theory use thinner elevators build slop outset have used much % slop trailing edge no apparent adverse affects overall performance important ensure slop elevator No slop should exist between bdllcrank flaps good after-the-fact means try set tle down recalcitrant hunter Simply drill Out elevator horn about /16 oversize mystique about using flaps eleva tors flat trailing edges dont pretend understand reasons since flies face Ive learned alrfoil theory number good guys time believe Les Mc Donald started great article three-time world champion Stiletto see July 1977 issue Model Aviation too-sharp leading edge wing can make ship susceptible hunting sharp leading edge causes minor angle-of-attack changes make greater changes coefficient lift airfoil particular instance adding nose weight may help cure hunting Whats too sharp easier fixes helped blamed thing looks sharp get out razor plane sandpaper kiss glossy finish goodbye have said some would ugly Hey guys See Nats Fly Stunt responding advertisers mention 1 read about ModelAviation total score some AMA Scale events looking chart easy see static scores important Using Rubber Scale example much easier properly gather necessary data other information carefully bulld 90-point 90% maximum static score model flies 40 sec get 40-static-point model fly 81 sec 90% maximum flight score consistent basis reasoning behind will now get explalning go about documenting model Step number Order new 1988-1989 AMA rule book once agaln contains copies score sheets score sheets used during judging model show exactly what judges looking might also want review Operational Fes totes section rules chosen Scale event determine what features included model Its better know plan details before model built rather decide after model completed should have added particular mechanism Step number two Outline Obtain good clear three-view drawing aircraft wish model whether kit scratch-bullt pro ject building kit begin measuring three-view plan outline Now time make outline modifications add scale rib spacing stringers etc scratch-building draw directly three-view using palr divid ers other scaling-up process enlarge three-view desired scale Remember three-view becomes three-view documentation Step number three Color search Obtaining color documentation particular aircraft modeling before building critical step enables build slight variations model antennas pitot tubes etc differ three-view Its important include notes presentation stating differences between model three-view re fer pictures prototype other written substantiating material color documentation can written aircraft obscure type might use artists airbrush renditions familiar types should photos com mon aircraft late Forties Step number four written presentation 162 Model Aviation
Edition: Model Aviation - 1988/08
Page Numbers: 70, 159, 162
HELP nature phone call received Stunt flier other day seeking help Precision Aerobatics vexing problems Stunt ship perfect way apparently incurable tendency hunt Now type hunting has nothing red hats cold feet antlers above fireplace mantel No Stunter goes hunting youre apt want shoot plane Hunting frustrating condition wherein ship cannot made settle nice flat groove level flight always climbing just little diving just little condition usually deteriorates wind severe enough may make level flight very exciting maneuver indeed What causes ship hunt Lets quickly exam ine forces acting Stunt ship level flight maintain level flight constant speed thrust must equal drag lift must equal weight order ship climb dive equilibrium must disturbed current discussion lets concentrate lift weight properly trimmed Stunt ship center gravity will slightly forward center lift wing Therefore since lift acts upward gravity downward combination forces will attempt cause ship dive lose planes tail exactly what would happen technical jargon tail horizontal stabilizer describes task tail per forms Its function stabilize wing par ticular attitude also functions change titude alrcraft called upon perform aerobatics tale another time youll pardon pun level flight tendency wing dive counteracted slight amount Up eleva tor almost imperceptible amount since amount lift necessary maintain three- four-pound Stunter level flight tiny percentage lift capability its lightly loaded wing ship therefore stabi lized elevator applying slight amount downward force tail offset opposing downward force aircrafts weight tal lift required wing will now sum weight airplane downward force tail Parenthetically Up elevator also means whereby symmetrically airfoiled Stunt wing produces lift Since contours top bottom wing identical pro duce no differential airflow rates fore no difference pressure above below wing generated necessary such wing always inclined some angle attack produce lift Once state equilibrium achieved ship should truck along nice please until acted upon some force disrupts bal ance force could either aerodynamic mechanical Aerodynamic forces would cause dis ruption equilibrium has achieved exception turbulent air pretty limited Since CL models airspeed continuously altered wind can have significant effect lift severity its effect can altered different states aircraft trim Lets take look occurs equation lift made up roughiy equal parts wing efficiency ie coefficient lift air density angle attack wing fourth component equation airspeed unlike first three factors lift increases square airspeed As fly circular levelflight pattern wind therefore lift will con stantly either increasing decreasing fly out wind As lift increases wind ship will climb vice versa down wind must therefore make continual inputs elevator trim wing new stabilized angle attack will precisely balance lift gravity maintain elusive four- sixfoot elevation strive maintain amount elevator change necessary situation depends large part distance between center-of-gravity center Continued page 159 Mike Ditrich Erie PA loves Steve Wooleys famous Cobra design L sixth hes built Weight 52 oz engine ST 46 Its lovely Kaz Minato has migrated Japan Los Angeles flies original-design Blue Max R Power specially fitted 05 45 FSR/ABC Kaz used engineer OS Hes now working Honda Motorcar R&D 70 Model Aviation Conoi Line Aerobatics Ted Fancher 158 FlyIng Cloud Isle Foster City CA 94404 Spectacular Don Hutchinsons semiscale Stearman Stunter rather small ship 34-in span Veco 19 power Flaps bottom wing reportedly have helped elimi nate mushing square maneuvers compared other biplanes Hutchinson photo Windy Urtnowskis Pro-Stunt Products handmade control handle Delrin bellcrank mentioned Ted June col umn Great-looking products motor pointing forward Flying Check plane balances point indicated plans before going out fly adding clay nose tail correct necessary Preset elevons bent up about /t6 Begin test gliding over some nice thick grass 163 wants glide fast give good solid push launch little adjust ing placement clay amount elevon deflection may neces sary proper trim Charge up motor hand launch gentle push glide trim anywhere near OK 163 should climb out nicely Try varying motors speed see what effects climb thrust line shown moder ate power setting 163 should climb series gentle power stalls somewhere between 75 100 ft cruise come down fast would like model have scalelike steep climb rate add slight amount downthrust motor model capable rise-off-ground flights Placed fairly smooth surface recently graded dirt road will ROG two five feet moder ate power setting might want experiment should possible install flattened tubing vertically wheels will drop off takeoff type flight trim model fly wheels Finishing Paint model very thin coats avoid weight buildup did airbrush spraying mixture nontautening nitrate dope pigment Floquil model train paints mix paint start new bottle Floquil pour off liquid Refill bottle thinner dope using shake mix spraying use mixture part new pigment mix five 10 parts clear dope Sigs Lite Coat works well coat color mixture thinned enough spray about right colors adds little weight used clear Contac shelf paper mask ing out camouflage patterns Flat spray enamels could also used model Make photocopy insignias glue get set ESCI %2-scale de cals Ju-52 did Me-163 has exciting project Flying wings have intrigued years hope too will try out fun excitement building fly ing CL Aerobatics/Fancher Continued page 70 lift nose-heavy ship greater elevator deflection necessary level flight greater change elevator position maintain constantly changing angle attack requirement wind As ihip gets too nose-heavy surprising pilot un able precisely manage input necessary maintain level track vast experience half-vast some peers might amend conventional flapped Stunters will have CG located 16% 18% average chord empty gas tank youve moved CU forward try cure hunting prob lem take out weight start looking else might also want ponder shift CU comes burning large amounts fuel out nose light Stunter might cause ship hunt unacceptably beginning flight settle down towards end CU moves aft can sec classic cures hunting airplane se weight ldom good idea True ship too tail-heavy might very well tough fly level would also have number other significant problems would very twitchy maneuvers would likely light lines flight would also float excessively dur ing glide t light lines difficult contrul glide Another aerodynamic source hunting could having adjustable control line leadOuts too far aft Since CU ship aligns self lead-out position flight can seen under condition Stunter would flying excessively crabbed condition center point lead-outs should almost never aft CU inch-anda-half Ted says ship hunts dead calm air too CU right 16% mean Continued page 162 August 1988 159 AllIMTh IPThThi TING SERVICE QUICK SERVICE OVER 300 ORDINATE SETS ON FILE SEND $200 and SASH long envelope samples list airfoils hand now SEND $500 SASE long plot yonr chord length set samples name anveral airfoils order preference Inclade photo copy shape data possible SEND $1000 PLOT SHAPE CATALOG 300 pIns airfoils 6 inch plots plas historical airfoil information other asefall airfoil data many pages STANDARD PLOTS. nader 10 inches paga Large chords availahle extra cost cost proportional chord length 20 chord twice cost 10 plot CUSTOM PLOTrING AVAILABLE Can modify camher thickness add pieces together can show varions skin thicknesses sop & bottom different TAPERED WING PLOTS $1000 Set ap pbs 50 cents per rib over 10 slightly higher THIS MONTHS HOT PLOTS NACA 0009 Oreat staht EPPLER 193 195 197 RAP 31 32 33 Can show 1/16 thor 1/8th Skin thickness NO EXTRA CHARGE Hot plots Only $100 over 10 $200 TI-lB PTERANODON PRESS nRtcas NEVELN PO BOX 3630 OAKLAND c 5161151630 hinge lines Control surface efficiency affected CL Aerobatics/Fancher by gap between fixed moving portions CL Scale/Boss Continued page 159 surface gap increases sur face deflected direction tightens Continued page 71 its deflected other unequal control response will result Sealing hinge lines elim inates differential also increases con trol effectiveness Doing good idea ship doesnt hunt chord lead-outs nice inch-and-aquarter aft Whats wrong Most hunting problems mechanical ongin can caused misaligned controls sticking control systems andmost common experiencepoorly adjusted control systems usually handle Heres couple easy ones no place competitive Stunter serious sport aerobatic ship sticky control systems cannot make precise input necessary precision flight youve gotta yank get controls move control surfaces should precisely aligned other wing tail stalled centerlines aligned other engines thrust line techni cal terms described zero degrees inci dence MIGHT find necessary some point tweak neutral flaps eleva tors relative another start should precisely neutral simultaneously youve got basics taken care lets take practice flight try diagnose solu tion attempting fly straight level ana lyze very carefully what airplane trying what must counteract its tenden cies likely find upright ship wants either climb dive its own must periodically correct condition invert ship will likely find condition reversed ie ship wanted climb upright wants de scend inverted vice versa may also find allowed climb ship will find some altitude other four six feet perfectly happy groove day long What probably happening hand position holding handle neutral causing controls slightly deflected thereby causing ship climb and/or dive Af ter make input correct situation return natural neutralwhich starts cycle again cure tendency simply shorten proper line handle /16 time until hunt goes away ship wants climb upright shorten Down line etc Other symptoms would support diag nosis would unequal turn rates forego ing problem apt find ship less responsive outside turns Adjusting handles neutral would correct both problems ship doesnt respond corrective procedure consider sealing flap elevator foregoing has helped still some tried true remedies Stunt foildore so some ugly ones involve knives such Some fliers advocate use elevators thinner fixed stab theory must deflect further before causing pitch change Thus flaps will deflected crease decrease lift also having pitch change results elevator deflec flon Some fliers including yours truly build some slop elevator thus allowing some flap movement deflecting elevator much same theory use thinner elevators build slop outset have used much % slop trailing edge no apparent adverse affects overall performance important ensure slop elevator No slop should exist between bdllcrank flaps good after-the-fact means try set tle down recalcitrant hunter Simply drill Out elevator horn about /16 oversize mystique about using flaps eleva tors flat trailing edges dont pretend understand reasons since flies face Ive learned alrfoil theory number good guys time believe Les Mc Donald started great article three-time world champion Stiletto see July 1977 issue Model Aviation too-sharp leading edge wing can make ship susceptible hunting sharp leading edge causes minor angle-of-attack changes make greater changes coefficient lift airfoil particular instance adding nose weight may help cure hunting Whats too sharp easier fixes helped blamed thing looks sharp get out razor plane sandpaper kiss glossy finish goodbye have said some would ugly Hey guys See Nats Fly Stunt responding advertisers mention 1 read about ModelAviation total score some AMA Scale events looking chart easy see static scores important Using Rubber Scale example much easier properly gather necessary data other information carefully bulld 90-point 90% maximum static score model flies 40 sec get 40-static-point model fly 81 sec 90% maximum flight score consistent basis reasoning behind will now get explalning go about documenting model Step number Order new 1988-1989 AMA rule book once agaln contains copies score sheets score sheets used during judging model show exactly what judges looking might also want review Operational Fes totes section rules chosen Scale event determine what features included model Its better know plan details before model built rather decide after model completed should have added particular mechanism Step number two Outline Obtain good clear three-view drawing aircraft wish model whether kit scratch-bullt pro ject building kit begin measuring three-view plan outline Now time make outline modifications add scale rib spacing stringers etc scratch-building draw directly three-view using palr divid ers other scaling-up process enlarge three-view desired scale Remember three-view becomes three-view documentation Step number three Color search Obtaining color documentation particular aircraft modeling before building critical step enables build slight variations model antennas pitot tubes etc differ three-view Its important include notes presentation stating differences between model three-view re fer pictures prototype other written substantiating material color documentation can written aircraft obscure type might use artists airbrush renditions familiar types should photos com mon aircraft late Forties Step number four written presentation 162 Model Aviation
Edition: Model Aviation - 1988/08
Page Numbers: 70, 159, 162
HELP nature phone call received Stunt flier other day seeking help Precision Aerobatics vexing problems Stunt ship perfect way apparently incurable tendency hunt Now type hunting has nothing red hats cold feet antlers above fireplace mantel No Stunter goes hunting youre apt want shoot plane Hunting frustrating condition wherein ship cannot made settle nice flat groove level flight always climbing just little diving just little condition usually deteriorates wind severe enough may make level flight very exciting maneuver indeed What causes ship hunt Lets quickly exam ine forces acting Stunt ship level flight maintain level flight constant speed thrust must equal drag lift must equal weight order ship climb dive equilibrium must disturbed current discussion lets concentrate lift weight properly trimmed Stunt ship center gravity will slightly forward center lift wing Therefore since lift acts upward gravity downward combination forces will attempt cause ship dive lose planes tail exactly what would happen technical jargon tail horizontal stabilizer describes task tail per forms Its function stabilize wing par ticular attitude also functions change titude alrcraft called upon perform aerobatics tale another time youll pardon pun level flight tendency wing dive counteracted slight amount Up eleva tor almost imperceptible amount since amount lift necessary maintain three- four-pound Stunter level flight tiny percentage lift capability its lightly loaded wing ship therefore stabi lized elevator applying slight amount downward force tail offset opposing downward force aircrafts weight tal lift required wing will now sum weight airplane downward force tail Parenthetically Up elevator also means whereby symmetrically airfoiled Stunt wing produces lift Since contours top bottom wing identical pro duce no differential airflow rates fore no difference pressure above below wing generated necessary such wing always inclined some angle attack produce lift Once state equilibrium achieved ship should truck along nice please until acted upon some force disrupts bal ance force could either aerodynamic mechanical Aerodynamic forces would cause dis ruption equilibrium has achieved exception turbulent air pretty limited Since CL models airspeed continuously altered wind can have significant effect lift severity its effect can altered different states aircraft trim Lets take look occurs equation lift made up roughiy equal parts wing efficiency ie coefficient lift air density angle attack wing fourth component equation airspeed unlike first three factors lift increases square airspeed As fly circular levelflight pattern wind therefore lift will con stantly either increasing decreasing fly out wind As lift increases wind ship will climb vice versa down wind must therefore make continual inputs elevator trim wing new stabilized angle attack will precisely balance lift gravity maintain elusive four- sixfoot elevation strive maintain amount elevator change necessary situation depends large part distance between center-of-gravity center Continued page 159 Mike Ditrich Erie PA loves Steve Wooleys famous Cobra design L sixth hes built Weight 52 oz engine ST 46 Its lovely Kaz Minato has migrated Japan Los Angeles flies original-design Blue Max R Power specially fitted 05 45 FSR/ABC Kaz used engineer OS Hes now working Honda Motorcar R&D 70 Model Aviation Conoi Line Aerobatics Ted Fancher 158 FlyIng Cloud Isle Foster City CA 94404 Spectacular Don Hutchinsons semiscale Stearman Stunter rather small ship 34-in span Veco 19 power Flaps bottom wing reportedly have helped elimi nate mushing square maneuvers compared other biplanes Hutchinson photo Windy Urtnowskis Pro-Stunt Products handmade control handle Delrin bellcrank mentioned Ted June col umn Great-looking products motor pointing forward Flying Check plane balances point indicated plans before going out fly adding clay nose tail correct necessary Preset elevons bent up about /t6 Begin test gliding over some nice thick grass 163 wants glide fast give good solid push launch little adjust ing placement clay amount elevon deflection may neces sary proper trim Charge up motor hand launch gentle push glide trim anywhere near OK 163 should climb out nicely Try varying motors speed see what effects climb thrust line shown moder ate power setting 163 should climb series gentle power stalls somewhere between 75 100 ft cruise come down fast would like model have scalelike steep climb rate add slight amount downthrust motor model capable rise-off-ground flights Placed fairly smooth surface recently graded dirt road will ROG two five feet moder ate power setting might want experiment should possible install flattened tubing vertically wheels will drop off takeoff type flight trim model fly wheels Finishing Paint model very thin coats avoid weight buildup did airbrush spraying mixture nontautening nitrate dope pigment Floquil model train paints mix paint start new bottle Floquil pour off liquid Refill bottle thinner dope using shake mix spraying use mixture part new pigment mix five 10 parts clear dope Sigs Lite Coat works well coat color mixture thinned enough spray about right colors adds little weight used clear Contac shelf paper mask ing out camouflage patterns Flat spray enamels could also used model Make photocopy insignias glue get set ESCI %2-scale de cals Ju-52 did Me-163 has exciting project Flying wings have intrigued years hope too will try out fun excitement building fly ing CL Aerobatics/Fancher Continued page 70 lift nose-heavy ship greater elevator deflection necessary level flight greater change elevator position maintain constantly changing angle attack requirement wind As ihip gets too nose-heavy surprising pilot un able precisely manage input necessary maintain level track vast experience half-vast some peers might amend conventional flapped Stunters will have CG located 16% 18% average chord empty gas tank youve moved CU forward try cure hunting prob lem take out weight start looking else might also want ponder shift CU comes burning large amounts fuel out nose light Stunter might cause ship hunt unacceptably beginning flight settle down towards end CU moves aft can sec classic cures hunting airplane se weight ldom good idea True ship too tail-heavy might very well tough fly level would also have number other significant problems would very twitchy maneuvers would likely light lines flight would also float excessively dur ing glide t light lines difficult contrul glide Another aerodynamic source hunting could having adjustable control line leadOuts too far aft Since CU ship aligns self lead-out position flight can seen under condition Stunter would flying excessively crabbed condition center point lead-outs should almost never aft CU inch-anda-half Ted says ship hunts dead calm air too CU right 16% mean Continued page 162 August 1988 159 AllIMTh IPThThi TING SERVICE QUICK SERVICE OVER 300 ORDINATE SETS ON FILE SEND $200 and SASH long envelope samples list airfoils hand now SEND $500 SASE long plot yonr chord length set samples name anveral airfoils order preference Inclade photo copy shape data possible SEND $1000 PLOT SHAPE CATALOG 300 pIns airfoils 6 inch plots plas historical airfoil information other asefall airfoil data many pages STANDARD PLOTS. nader 10 inches paga Large chords availahle extra cost cost proportional chord length 20 chord twice cost 10 plot CUSTOM PLOTrING AVAILABLE Can modify camher thickness add pieces together can show varions skin thicknesses sop & bottom different TAPERED WING PLOTS $1000 Set ap pbs 50 cents per rib over 10 slightly higher THIS MONTHS HOT PLOTS NACA 0009 Oreat staht EPPLER 193 195 197 RAP 31 32 33 Can show 1/16 thor 1/8th Skin thickness NO EXTRA CHARGE Hot plots Only $100 over 10 $200 TI-lB PTERANODON PRESS nRtcas NEVELN PO BOX 3630 OAKLAND c 5161151630 hinge lines Control surface efficiency affected CL Aerobatics/Fancher by gap between fixed moving portions CL Scale/Boss Continued page 159 surface gap increases sur face deflected direction tightens Continued page 71 its deflected other unequal control response will result Sealing hinge lines elim inates differential also increases con trol effectiveness Doing good idea ship doesnt hunt chord lead-outs nice inch-and-aquarter aft Whats wrong Most hunting problems mechanical ongin can caused misaligned controls sticking control systems andmost common experiencepoorly adjusted control systems usually handle Heres couple easy ones no place competitive Stunter serious sport aerobatic ship sticky control systems cannot make precise input necessary precision flight youve gotta yank get controls move control surfaces should precisely aligned other wing tail stalled centerlines aligned other engines thrust line techni cal terms described zero degrees inci dence MIGHT find necessary some point tweak neutral flaps eleva tors relative another start should precisely neutral simultaneously youve got basics taken care lets take practice flight try diagnose solu tion attempting fly straight level ana lyze very carefully what airplane trying what must counteract its tenden cies likely find upright ship wants either climb dive its own must periodically correct condition invert ship will likely find condition reversed ie ship wanted climb upright wants de scend inverted vice versa may also find allowed climb ship will find some altitude other four six feet perfectly happy groove day long What probably happening hand position holding handle neutral causing controls slightly deflected thereby causing ship climb and/or dive Af ter make input correct situation return natural neutralwhich starts cycle again cure tendency simply shorten proper line handle /16 time until hunt goes away ship wants climb upright shorten Down line etc Other symptoms would support diag nosis would unequal turn rates forego ing problem apt find ship less responsive outside turns Adjusting handles neutral would correct both problems ship doesnt respond corrective procedure consider sealing flap elevator foregoing has helped still some tried true remedies Stunt foildore so some ugly ones involve knives such Some fliers advocate use elevators thinner fixed stab theory must deflect further before causing pitch change Thus flaps will deflected crease decrease lift also having pitch change results elevator deflec flon Some fliers including yours truly build some slop elevator thus allowing some flap movement deflecting elevator much same theory use thinner elevators build slop outset have used much % slop trailing edge no apparent adverse affects overall performance important ensure slop elevator No slop should exist between bdllcrank flaps good after-the-fact means try set tle down recalcitrant hunter Simply drill Out elevator horn about /16 oversize mystique about using flaps eleva tors flat trailing edges dont pretend understand reasons since flies face Ive learned alrfoil theory number good guys time believe Les Mc Donald started great article three-time world champion Stiletto see July 1977 issue Model Aviation too-sharp leading edge wing can make ship susceptible hunting sharp leading edge causes minor angle-of-attack changes make greater changes coefficient lift airfoil particular instance adding nose weight may help cure hunting Whats too sharp easier fixes helped blamed thing looks sharp get out razor plane sandpaper kiss glossy finish goodbye have said some would ugly Hey guys See Nats Fly Stunt responding advertisers mention 1 read about ModelAviation total score some AMA Scale events looking chart easy see static scores important Using Rubber Scale example much easier properly gather necessary data other information carefully bulld 90-point 90% maximum static score model flies 40 sec get 40-static-point model fly 81 sec 90% maximum flight score consistent basis reasoning behind will now get explalning go about documenting model Step number Order new 1988-1989 AMA rule book once agaln contains copies score sheets score sheets used during judging model show exactly what judges looking might also want review Operational Fes totes section rules chosen Scale event determine what features included model Its better know plan details before model built rather decide after model completed should have added particular mechanism Step number two Outline Obtain good clear three-view drawing aircraft wish model whether kit scratch-bullt pro ject building kit begin measuring three-view plan outline Now time make outline modifications add scale rib spacing stringers etc scratch-building draw directly three-view using palr divid ers other scaling-up process enlarge three-view desired scale Remember three-view becomes three-view documentation Step number three Color search Obtaining color documentation particular aircraft modeling before building critical step enables build slight variations model antennas pitot tubes etc differ three-view Its important include notes presentation stating differences between model three-view re fer pictures prototype other written substantiating material color documentation can written aircraft obscure type might use artists airbrush renditions familiar types should photos com mon aircraft late Forties Step number four written presentation 162 Model Aviation