RECENTLY received letter Al Seidow ski Cleveland OH requested con tinue light treatment aero princi pies name sounded familiarand struck Al Seidowski probably responsi ble current AMA Pattern classes can remember back Sixties member Western Ohio Radio Kon trol Society WORKS Dayton OH Al Seidowski came WORKS club meeting pro mote new style Pattern competition Prior time Pattern classes Classes 1 2 3 Novice Expert Class 1 air craft rudder throttle control Class 2 air craft rudder elevator throttle control Class 3 airplanes rudder elevator aile ron throttle control airplane flew determined class people Classes 1 2 big disadvantages over come got very good using con trols produce some very nice maneu vers bunch old-timers still around Jim Goad Indy R/C bet ter Class fliers remember correctly Bud kinson currently produces Scale col umn Model Airplane News famous Class II airplane called Aristocat could produce three axial rolls no aile rons Bud won Nats Class 2 least once Anyway Al promoted Pattern class system airplanes three-axis controls patterns different complexity faced lot stiff resistance because peo ple liked what didnt want build new airplanes compete dont know else promoting same idea Al Seidowski knew about So thanks Al good ideas efforts put dramatically change way Pattern flown letter came Conrad Manthey Mem phis TN touched familiar chord wrote have problem concerning aerodynam ics could answer Its really true makes feel like Wright Broth ers Theodore von Karman Bernard Etkin rolled RVP Last year built Super Kaos 40 flew great except verted nosed down toward ground should flew little Down el evator regular flight remember changing wing incidence lowering leading edge center elevator give plane positive incidence inverted result no change elevator centered Next engine incidence changed point up inverted Downthrusr RVP nothing happened again think remember mov ing center-of-gravity back no avail adjustments made time just built new Pattern ship seems have same problem among others flies Down elevator too might common problem would appreciate answer cause baffled Does letter touch familiar chords certainly does remem ber Phoenix 6 drove crazy ma neuvers required airplane rolled inverted would immediately head ground unless used very generous amounts Down elevator performed Three Hori zontal Rolls elevator stick looked like sawing wood big saw Three Reverse Out side Loops terror start Four Point Roll Slow Roll werent much better ever did learn adjust got pretty good hiding what thought design deficiency Don Lowe rocket engineer watched sawing away Phoenixs elevator con trol contest told aerodynamicist looked like center mass air plane too far forward figured should know something about airplane designed moved center mass back flew better So moved back gob flew great concerned airplane would unstable pitch deliberately gotten center mass too far forward Since unruly Phoenix 6 have flown sev eral airplanes exhibited same symp toms Invariably have solved problem sys tematically moving center mass aft latest airplane T-2A Mk II add two long strips stick-on weights get desired results Now airplane flies inverted fine lands like pussycat didnt before Sounds like cure-all no bad side effects right Like solutions has some com promise built As airplane center mass moved aft trim becomes sensitive elevator control effectiveness increases must have servos center accurately control linkages solid airplane will spooky trim pitching up moment down next addition much less control input will required pitch airplane have too much elevator movement airplane will jump whenever touch control moving center mass back small steps desensitize elevator controls you get center mass right youll need tap Down elevator point rolls may need horizontal rolls Boy what nice feeling 44 Model Aviation Rado Confrol Sport Aerobatics Ron Van Putte ill Sleepy Oaks Rd Ft Walton Beach FL 32548 Mark Grubbs Taylors SC uses generic wall-mount shelf standards brackets hardware store create neat-looking model storage racks obviously likes tall-draggers does Van Putte need six servos TR MK ii TuseIage Iwo tor elevator used rudder throttle mixture control nosc sear retract means has least two wing aileron retract got Figure 1 Figure 2 Figure 3 Aerodynamics facts continue Ron talks about tails month refers vertical fins column Theres no such thing too much tail right Wrong Too much vertical fin tail causes air plane stability problem called spiral instability must mean theres no such thing too little tail Obviously thats wrong too once old fuel-soaked Beachcomber tail de parted dive never before seen screwy maneuver airplane did before tried fly under runway So theres obviously happy medium out somewhere Suppose youve decided airplane needs vertical fin effectiveness What achieve First lets sake simplistic look effectiveness means verti cal fin area needed right necessarily hut will work right vertical fin looked like Figure 1 would add area make look like Figure 2 Figure 3 get greater vertical fin effectiveness Before get answer need some facts Vertical fins horizontal stabilizers aerodynamic surfaces just like wings mea sure effective producing force area However another measure aerodynamicists use measure effective ness aspect ratio Aspect ratio nothing ratio effective length di vided effective width rectangular wing aspect ratio span divided chord vertical fin aspect ratio Continued page 133 New Fourmost Products Cooney Gapless Hinge 45 0 New Kit CAJUN TWO STEP INTERMEDIATE TRAINER Slows Walk yet Fully Aerobatic Complete Kit 8998 56 Wing 40 Length 40 Engine 4 lbs 4 CH New Improved Cooney Gapless Hinge added strength new white color easy stall hinge Gapless Hinge extrud ed strip polyurethane completely fuelproof forms perfectly gapless con trol surface seal greatly creases areodynamic efficiency Available two sizes Small 1/8 1/4 Large 1/4 larger Price $350 per 3 ft length information about Cooney Gapless Hinges other innovative model products Fourmost send stamped self-addressed business size envelope FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 503 357-2732 Tiger Tail 4 New Deluxe Kit t Fiber Glass Fuse & Belly Pan Foam Wing & stab Balsa & Plywood Composite Construction Balsa Fuse w/Fiberglass Cilun RIC Pmductl Top DeckCbin Cowl & Belly Pan 112 Rasie SI Foam Wing & Hwd Lafayelle LA 70508 Ask about Kit & Eng Combos 318 232-7448 Dealer inquiries invited June 1988 45 16495 72 Wing 800 sq 1L15FULL LINE METAL SPECIALISTS H RC Electrics/Kopski Continued page 129 pressed well onto motor shaft close motors end bell such gear puller can engaged tape end bell pre vent motor magnets sucking metal particles liberated grinding process Finally original pinion removed new Astro pinion can pressed place best done carefully drill press some other type press Whatever dont bang motor shaft gear hammering device Doing almost certain give regrets Ive installed 4046 several ferrites find shim usually needed between mo tor front-end bell back surface gear drive housing properly space engage new gears shim generally about / % thick depending motor gear place ment etc suggest using some noncompressible substance like sheet aluminum modeling ply wood cardboard such back tablet paper thin stack index card material Cut shim fully back up space between drive housing front end bell DO NOT recommend spacing done just flat washers gear housing mounting screwsan easy action tempting its simplic ity does afford satisfactory sup port drive Motors Ive run 4046 include couple Kyoshos DSC Great Planes Thrustmaster old Astro can motor Interest ingly enough DSC good choice drive because timed run best clock wise direction means motor brush angle such motor runs efficiently used reversing gear drives like 4046 mostbut allothers As far can tell Thrustmaster timed close neutral runs about equally well CW CCW Both economy motors have fixed adjustable considerable ef fort timing Later columns will include some performance information bench runs various motors props used Astro 4046 gear drive Thus ends another fun exchange Please forward comment question SASE please address given top first page column Happy Silent Electric Landings Everyone RC Aerobatics/Van Putte Continued page 45 roughly twice height divided average chord effective aerodynamic surface highest aspect ratio given area Which has higher aspect ratio Figure 2 Figure 3 Figure 3 course Since Ive care fully drawn both have same area fin Figure 3 has greater effectiveness Figure 2 Area increase way increase vertical fin effectiveness Have ever won dered fancy wing tip additions improve wing performance reason work cause increase effective aspect ratio wing actually fool air mol ecules thinking going past longer wing higher aspect ratio tip plates winglets conical tips fences really work well wings Unfortunately some work well direction youre just trying produce lift thats fine However vertical fins need work both directions artificial aspect ratio improver works well vertical fins tip plate design tip plate critical long covers tip has width least three times maximum thickness tip course make tip plate very big will very effective youll have another horizon tal tail up too will also note addition verticalfin tip plate will increase rudder effectiveness works same reason increases verti cal fin effectiveness Does mean best cures ver tical fins always increasing fin aspect ratio adding tip plates Unfortunately no have Pattern airplane both cures tend produce adverse roll Right rud der applied airplane tends roll left vice versa happens wing dihedral needs increased Airplane design full compro mises like RC Scale/Wischers Continued page 47 cern blessed today abundance fine finishing materials having controlled shrink age silk-and-dope finishes entailed end less series steps obliterate balsa grain respectable finish Scale model Silk soft thin flexible pulls down balsa grain doesnt matter whether balsa grain filled before after covering weight addition filler about equal silk itself introduc es pattern weave needs filled really smooth finish old system past required coats dope mixed talcum powder applied brush sanding carefully tween coats assure removing filler coats cutting silk underneath final talc coat sealed sprayed coat clear dope Without step talcum powder would leach back final color coats dull finish silk-and-dope method finishing can still followed Scale modelers dont object multiple steps much time spent pro cess Its popularity has diminished some old-timers continue use lengthy process modern surface-preparation technique substructure beneath less important can fill bare balsa K&B primer follow di rectly paint short process isnt used models prefer harden surface fabric coverings Koverall Super Coy erite silk use filler areas need perfectly smooth Fiberglass surfaces provide surprisingly lightweight cover supplies strength exterior also re quire filling schedule before final color coats extra strengthening provided fi bergiass can sometimes mean reduced structure beneath Pilot sculptures comes time stan dard hobby shop dummy pilots doni fit appli cation Wrong size apparel reasons re jection decide become amateur sculp tors make own materials probably already workshop small blocks bass wood leftover chunks styrene foam Bass wood carves well demands bit deft carv ing skill render psuedo-human likeness An THE LEADER IN COMPETITION NEW 15 DIA 116 NEW PRO SERIES 3 II \ / NEW HIGH TECH AIRFOIL SECTION 10T020% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUEL PROOF HIGH LUSTER FINISH DIAPITCHPRICE 53/34 634 72833/,456 833/,4568 9 4566A77/ 10 6W8W 10 6EW II 4677/7h78 11 5W 11 6EW ll/ 67 12 4W 12 5W 12 56 13 56 14 56 15 56 16 4/N 16 678 RCPYLON RACING SERIES 500 DIA PITCHPRICE 7 SN 5/N 8I 6778 SERIES 400C 86677/7 9 777 W WIDE BLADE EW EXTRA WIDE N NARROW PROPELLERS 4 DESIGN TAILORED HELICAL PITCH DEVELOPEDTOGIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALL THE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW PITCH THP PRICE 66 Iz 7 7 I/ 677 Ia 8 677/a 8 67 678 June 1988 133
Edition: Model Aviation - 1988/06
Page Numbers: 44, 45, 133
RECENTLY received letter Al Seidow ski Cleveland OH requested con tinue light treatment aero princi pies name sounded familiarand struck Al Seidowski probably responsi ble current AMA Pattern classes can remember back Sixties member Western Ohio Radio Kon trol Society WORKS Dayton OH Al Seidowski came WORKS club meeting pro mote new style Pattern competition Prior time Pattern classes Classes 1 2 3 Novice Expert Class 1 air craft rudder throttle control Class 2 air craft rudder elevator throttle control Class 3 airplanes rudder elevator aile ron throttle control airplane flew determined class people Classes 1 2 big disadvantages over come got very good using con trols produce some very nice maneu vers bunch old-timers still around Jim Goad Indy R/C bet ter Class fliers remember correctly Bud kinson currently produces Scale col umn Model Airplane News famous Class II airplane called Aristocat could produce three axial rolls no aile rons Bud won Nats Class 2 least once Anyway Al promoted Pattern class system airplanes three-axis controls patterns different complexity faced lot stiff resistance because peo ple liked what didnt want build new airplanes compete dont know else promoting same idea Al Seidowski knew about So thanks Al good ideas efforts put dramatically change way Pattern flown letter came Conrad Manthey Mem phis TN touched familiar chord wrote have problem concerning aerodynam ics could answer Its really true makes feel like Wright Broth ers Theodore von Karman Bernard Etkin rolled RVP Last year built Super Kaos 40 flew great except verted nosed down toward ground should flew little Down el evator regular flight remember changing wing incidence lowering leading edge center elevator give plane positive incidence inverted result no change elevator centered Next engine incidence changed point up inverted Downthrusr RVP nothing happened again think remember mov ing center-of-gravity back no avail adjustments made time just built new Pattern ship seems have same problem among others flies Down elevator too might common problem would appreciate answer cause baffled Does letter touch familiar chords certainly does remem ber Phoenix 6 drove crazy ma neuvers required airplane rolled inverted would immediately head ground unless used very generous amounts Down elevator performed Three Hori zontal Rolls elevator stick looked like sawing wood big saw Three Reverse Out side Loops terror start Four Point Roll Slow Roll werent much better ever did learn adjust got pretty good hiding what thought design deficiency Don Lowe rocket engineer watched sawing away Phoenixs elevator con trol contest told aerodynamicist looked like center mass air plane too far forward figured should know something about airplane designed moved center mass back flew better So moved back gob flew great concerned airplane would unstable pitch deliberately gotten center mass too far forward Since unruly Phoenix 6 have flown sev eral airplanes exhibited same symp toms Invariably have solved problem sys tematically moving center mass aft latest airplane T-2A Mk II add two long strips stick-on weights get desired results Now airplane flies inverted fine lands like pussycat didnt before Sounds like cure-all no bad side effects right Like solutions has some com promise built As airplane center mass moved aft trim becomes sensitive elevator control effectiveness increases must have servos center accurately control linkages solid airplane will spooky trim pitching up moment down next addition much less control input will required pitch airplane have too much elevator movement airplane will jump whenever touch control moving center mass back small steps desensitize elevator controls you get center mass right youll need tap Down elevator point rolls may need horizontal rolls Boy what nice feeling 44 Model Aviation Rado Confrol Sport Aerobatics Ron Van Putte ill Sleepy Oaks Rd Ft Walton Beach FL 32548 Mark Grubbs Taylors SC uses generic wall-mount shelf standards brackets hardware store create neat-looking model storage racks obviously likes tall-draggers does Van Putte need six servos TR MK ii TuseIage Iwo tor elevator used rudder throttle mixture control nosc sear retract means has least two wing aileron retract got Figure 1 Figure 2 Figure 3 Aerodynamics facts continue Ron talks about tails month refers vertical fins column Theres no such thing too much tail right Wrong Too much vertical fin tail causes air plane stability problem called spiral instability must mean theres no such thing too little tail Obviously thats wrong too once old fuel-soaked Beachcomber tail de parted dive never before seen screwy maneuver airplane did before tried fly under runway So theres obviously happy medium out somewhere Suppose youve decided airplane needs vertical fin effectiveness What achieve First lets sake simplistic look effectiveness means verti cal fin area needed right necessarily hut will work right vertical fin looked like Figure 1 would add area make look like Figure 2 Figure 3 get greater vertical fin effectiveness Before get answer need some facts Vertical fins horizontal stabilizers aerodynamic surfaces just like wings mea sure effective producing force area However another measure aerodynamicists use measure effective ness aspect ratio Aspect ratio nothing ratio effective length di vided effective width rectangular wing aspect ratio span divided chord vertical fin aspect ratio Continued page 133 New Fourmost Products Cooney Gapless Hinge 45 0 New Kit CAJUN TWO STEP INTERMEDIATE TRAINER Slows Walk yet Fully Aerobatic Complete Kit 8998 56 Wing 40 Length 40 Engine 4 lbs 4 CH New Improved Cooney Gapless Hinge added strength new white color easy stall hinge Gapless Hinge extrud ed strip polyurethane completely fuelproof forms perfectly gapless con trol surface seal greatly creases areodynamic efficiency Available two sizes Small 1/8 1/4 Large 1/4 larger Price $350 per 3 ft length information about Cooney Gapless Hinges other innovative model products Fourmost send stamped self-addressed business size envelope FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 503 357-2732 Tiger Tail 4 New Deluxe Kit t Fiber Glass Fuse & Belly Pan Foam Wing & stab Balsa & Plywood Composite Construction Balsa Fuse w/Fiberglass Cilun RIC Pmductl Top DeckCbin Cowl & Belly Pan 112 Rasie SI Foam Wing & Hwd Lafayelle LA 70508 Ask about Kit & Eng Combos 318 232-7448 Dealer inquiries invited June 1988 45 16495 72 Wing 800 sq 1L15FULL LINE METAL SPECIALISTS H RC Electrics/Kopski Continued page 129 pressed well onto motor shaft close motors end bell such gear puller can engaged tape end bell pre vent motor magnets sucking metal particles liberated grinding process Finally original pinion removed new Astro pinion can pressed place best done carefully drill press some other type press Whatever dont bang motor shaft gear hammering device Doing almost certain give regrets Ive installed 4046 several ferrites find shim usually needed between mo tor front-end bell back surface gear drive housing properly space engage new gears shim generally about / % thick depending motor gear place ment etc suggest using some noncompressible substance like sheet aluminum modeling ply wood cardboard such back tablet paper thin stack index card material Cut shim fully back up space between drive housing front end bell DO NOT recommend spacing done just flat washers gear housing mounting screwsan easy action tempting its simplic ity does afford satisfactory sup port drive Motors Ive run 4046 include couple Kyoshos DSC Great Planes Thrustmaster old Astro can motor Interest ingly enough DSC good choice drive because timed run best clock wise direction means motor brush angle such motor runs efficiently used reversing gear drives like 4046 mostbut allothers As far can tell Thrustmaster timed close neutral runs about equally well CW CCW Both economy motors have fixed adjustable considerable ef fort timing Later columns will include some performance information bench runs various motors props used Astro 4046 gear drive Thus ends another fun exchange Please forward comment question SASE please address given top first page column Happy Silent Electric Landings Everyone RC Aerobatics/Van Putte Continued page 45 roughly twice height divided average chord effective aerodynamic surface highest aspect ratio given area Which has higher aspect ratio Figure 2 Figure 3 Figure 3 course Since Ive care fully drawn both have same area fin Figure 3 has greater effectiveness Figure 2 Area increase way increase vertical fin effectiveness Have ever won dered fancy wing tip additions improve wing performance reason work cause increase effective aspect ratio wing actually fool air mol ecules thinking going past longer wing higher aspect ratio tip plates winglets conical tips fences really work well wings Unfortunately some work well direction youre just trying produce lift thats fine However vertical fins need work both directions artificial aspect ratio improver works well vertical fins tip plate design tip plate critical long covers tip has width least three times maximum thickness tip course make tip plate very big will very effective youll have another horizon tal tail up too will also note addition verticalfin tip plate will increase rudder effectiveness works same reason increases verti cal fin effectiveness Does mean best cures ver tical fins always increasing fin aspect ratio adding tip plates Unfortunately no have Pattern airplane both cures tend produce adverse roll Right rud der applied airplane tends roll left vice versa happens wing dihedral needs increased Airplane design full compro mises like RC Scale/Wischers Continued page 47 cern blessed today abundance fine finishing materials having controlled shrink age silk-and-dope finishes entailed end less series steps obliterate balsa grain respectable finish Scale model Silk soft thin flexible pulls down balsa grain doesnt matter whether balsa grain filled before after covering weight addition filler about equal silk itself introduc es pattern weave needs filled really smooth finish old system past required coats dope mixed talcum powder applied brush sanding carefully tween coats assure removing filler coats cutting silk underneath final talc coat sealed sprayed coat clear dope Without step talcum powder would leach back final color coats dull finish silk-and-dope method finishing can still followed Scale modelers dont object multiple steps much time spent pro cess Its popularity has diminished some old-timers continue use lengthy process modern surface-preparation technique substructure beneath less important can fill bare balsa K&B primer follow di rectly paint short process isnt used models prefer harden surface fabric coverings Koverall Super Coy erite silk use filler areas need perfectly smooth Fiberglass surfaces provide surprisingly lightweight cover supplies strength exterior also re quire filling schedule before final color coats extra strengthening provided fi bergiass can sometimes mean reduced structure beneath Pilot sculptures comes time stan dard hobby shop dummy pilots doni fit appli cation Wrong size apparel reasons re jection decide become amateur sculp tors make own materials probably already workshop small blocks bass wood leftover chunks styrene foam Bass wood carves well demands bit deft carv ing skill render psuedo-human likeness An THE LEADER IN COMPETITION NEW 15 DIA 116 NEW PRO SERIES 3 II \ / NEW HIGH TECH AIRFOIL SECTION 10T020% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUEL PROOF HIGH LUSTER FINISH DIAPITCHPRICE 53/34 634 72833/,456 833/,4568 9 4566A77/ 10 6W8W 10 6EW II 4677/7h78 11 5W 11 6EW ll/ 67 12 4W 12 5W 12 56 13 56 14 56 15 56 16 4/N 16 678 RCPYLON RACING SERIES 500 DIA PITCHPRICE 7 SN 5/N 8I 6778 SERIES 400C 86677/7 9 777 W WIDE BLADE EW EXTRA WIDE N NARROW PROPELLERS 4 DESIGN TAILORED HELICAL PITCH DEVELOPEDTOGIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALL THE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW PITCH THP PRICE 66 Iz 7 7 I/ 677 Ia 8 677/a 8 67 678 June 1988 133
Edition: Model Aviation - 1988/06
Page Numbers: 44, 45, 133
RECENTLY received letter Al Seidow ski Cleveland OH requested con tinue light treatment aero princi pies name sounded familiarand struck Al Seidowski probably responsi ble current AMA Pattern classes can remember back Sixties member Western Ohio Radio Kon trol Society WORKS Dayton OH Al Seidowski came WORKS club meeting pro mote new style Pattern competition Prior time Pattern classes Classes 1 2 3 Novice Expert Class 1 air craft rudder throttle control Class 2 air craft rudder elevator throttle control Class 3 airplanes rudder elevator aile ron throttle control airplane flew determined class people Classes 1 2 big disadvantages over come got very good using con trols produce some very nice maneu vers bunch old-timers still around Jim Goad Indy R/C bet ter Class fliers remember correctly Bud kinson currently produces Scale col umn Model Airplane News famous Class II airplane called Aristocat could produce three axial rolls no aile rons Bud won Nats Class 2 least once Anyway Al promoted Pattern class system airplanes three-axis controls patterns different complexity faced lot stiff resistance because peo ple liked what didnt want build new airplanes compete dont know else promoting same idea Al Seidowski knew about So thanks Al good ideas efforts put dramatically change way Pattern flown letter came Conrad Manthey Mem phis TN touched familiar chord wrote have problem concerning aerodynam ics could answer Its really true makes feel like Wright Broth ers Theodore von Karman Bernard Etkin rolled RVP Last year built Super Kaos 40 flew great except verted nosed down toward ground should flew little Down el evator regular flight remember changing wing incidence lowering leading edge center elevator give plane positive incidence inverted result no change elevator centered Next engine incidence changed point up inverted Downthrusr RVP nothing happened again think remember mov ing center-of-gravity back no avail adjustments made time just built new Pattern ship seems have same problem among others flies Down elevator too might common problem would appreciate answer cause baffled Does letter touch familiar chords certainly does remem ber Phoenix 6 drove crazy ma neuvers required airplane rolled inverted would immediately head ground unless used very generous amounts Down elevator performed Three Hori zontal Rolls elevator stick looked like sawing wood big saw Three Reverse Out side Loops terror start Four Point Roll Slow Roll werent much better ever did learn adjust got pretty good hiding what thought design deficiency Don Lowe rocket engineer watched sawing away Phoenixs elevator con trol contest told aerodynamicist looked like center mass air plane too far forward figured should know something about airplane designed moved center mass back flew better So moved back gob flew great concerned airplane would unstable pitch deliberately gotten center mass too far forward Since unruly Phoenix 6 have flown sev eral airplanes exhibited same symp toms Invariably have solved problem sys tematically moving center mass aft latest airplane T-2A Mk II add two long strips stick-on weights get desired results Now airplane flies inverted fine lands like pussycat didnt before Sounds like cure-all no bad side effects right Like solutions has some com promise built As airplane center mass moved aft trim becomes sensitive elevator control effectiveness increases must have servos center accurately control linkages solid airplane will spooky trim pitching up moment down next addition much less control input will required pitch airplane have too much elevator movement airplane will jump whenever touch control moving center mass back small steps desensitize elevator controls you get center mass right youll need tap Down elevator point rolls may need horizontal rolls Boy what nice feeling 44 Model Aviation Rado Confrol Sport Aerobatics Ron Van Putte ill Sleepy Oaks Rd Ft Walton Beach FL 32548 Mark Grubbs Taylors SC uses generic wall-mount shelf standards brackets hardware store create neat-looking model storage racks obviously likes tall-draggers does Van Putte need six servos TR MK ii TuseIage Iwo tor elevator used rudder throttle mixture control nosc sear retract means has least two wing aileron retract got Figure 1 Figure 2 Figure 3 Aerodynamics facts continue Ron talks about tails month refers vertical fins column Theres no such thing too much tail right Wrong Too much vertical fin tail causes air plane stability problem called spiral instability must mean theres no such thing too little tail Obviously thats wrong too once old fuel-soaked Beachcomber tail de parted dive never before seen screwy maneuver airplane did before tried fly under runway So theres obviously happy medium out somewhere Suppose youve decided airplane needs vertical fin effectiveness What achieve First lets sake simplistic look effectiveness means verti cal fin area needed right necessarily hut will work right vertical fin looked like Figure 1 would add area make look like Figure 2 Figure 3 get greater vertical fin effectiveness Before get answer need some facts Vertical fins horizontal stabilizers aerodynamic surfaces just like wings mea sure effective producing force area However another measure aerodynamicists use measure effective ness aspect ratio Aspect ratio nothing ratio effective length di vided effective width rectangular wing aspect ratio span divided chord vertical fin aspect ratio Continued page 133 New Fourmost Products Cooney Gapless Hinge 45 0 New Kit CAJUN TWO STEP INTERMEDIATE TRAINER Slows Walk yet Fully Aerobatic Complete Kit 8998 56 Wing 40 Length 40 Engine 4 lbs 4 CH New Improved Cooney Gapless Hinge added strength new white color easy stall hinge Gapless Hinge extrud ed strip polyurethane completely fuelproof forms perfectly gapless con trol surface seal greatly creases areodynamic efficiency Available two sizes Small 1/8 1/4 Large 1/4 larger Price $350 per 3 ft length information about Cooney Gapless Hinges other innovative model products Fourmost send stamped self-addressed business size envelope FOURMOST PRODUCTS 4040 24th Avenue Forest Grove OR 97116 503 357-2732 Tiger Tail 4 New Deluxe Kit t Fiber Glass Fuse & Belly Pan Foam Wing & stab Balsa & Plywood Composite Construction Balsa Fuse w/Fiberglass Cilun RIC Pmductl Top DeckCbin Cowl & Belly Pan 112 Rasie SI Foam Wing & Hwd Lafayelle LA 70508 Ask about Kit & Eng Combos 318 232-7448 Dealer inquiries invited June 1988 45 16495 72 Wing 800 sq 1L15FULL LINE METAL SPECIALISTS H RC Electrics/Kopski Continued page 129 pressed well onto motor shaft close motors end bell such gear puller can engaged tape end bell pre vent motor magnets sucking metal particles liberated grinding process Finally original pinion removed new Astro pinion can pressed place best done carefully drill press some other type press Whatever dont bang motor shaft gear hammering device Doing almost certain give regrets Ive installed 4046 several ferrites find shim usually needed between mo tor front-end bell back surface gear drive housing properly space engage new gears shim generally about / % thick depending motor gear place ment etc suggest using some noncompressible substance like sheet aluminum modeling ply wood cardboard such back tablet paper thin stack index card material Cut shim fully back up space between drive housing front end bell DO NOT recommend spacing done just flat washers gear housing mounting screwsan easy action tempting its simplic ity does afford satisfactory sup port drive Motors Ive run 4046 include couple Kyoshos DSC Great Planes Thrustmaster old Astro can motor Interest ingly enough DSC good choice drive because timed run best clock wise direction means motor brush angle such motor runs efficiently used reversing gear drives like 4046 mostbut allothers As far can tell Thrustmaster timed close neutral runs about equally well CW CCW Both economy motors have fixed adjustable considerable ef fort timing Later columns will include some performance information bench runs various motors props used Astro 4046 gear drive Thus ends another fun exchange Please forward comment question SASE please address given top first page column Happy Silent Electric Landings Everyone RC Aerobatics/Van Putte Continued page 45 roughly twice height divided average chord effective aerodynamic surface highest aspect ratio given area Which has higher aspect ratio Figure 2 Figure 3 Figure 3 course Since Ive care fully drawn both have same area fin Figure 3 has greater effectiveness Figure 2 Area increase way increase vertical fin effectiveness Have ever won dered fancy wing tip additions improve wing performance reason work cause increase effective aspect ratio wing actually fool air mol ecules thinking going past longer wing higher aspect ratio tip plates winglets conical tips fences really work well wings Unfortunately some work well direction youre just trying produce lift thats fine However vertical fins need work both directions artificial aspect ratio improver works well vertical fins tip plate design tip plate critical long covers tip has width least three times maximum thickness tip course make tip plate very big will very effective youll have another horizon tal tail up too will also note addition verticalfin tip plate will increase rudder effectiveness works same reason increases verti cal fin effectiveness Does mean best cures ver tical fins always increasing fin aspect ratio adding tip plates Unfortunately no have Pattern airplane both cures tend produce adverse roll Right rud der applied airplane tends roll left vice versa happens wing dihedral needs increased Airplane design full compro mises like RC Scale/Wischers Continued page 47 cern blessed today abundance fine finishing materials having controlled shrink age silk-and-dope finishes entailed end less series steps obliterate balsa grain respectable finish Scale model Silk soft thin flexible pulls down balsa grain doesnt matter whether balsa grain filled before after covering weight addition filler about equal silk itself introduc es pattern weave needs filled really smooth finish old system past required coats dope mixed talcum powder applied brush sanding carefully tween coats assure removing filler coats cutting silk underneath final talc coat sealed sprayed coat clear dope Without step talcum powder would leach back final color coats dull finish silk-and-dope method finishing can still followed Scale modelers dont object multiple steps much time spent pro cess Its popularity has diminished some old-timers continue use lengthy process modern surface-preparation technique substructure beneath less important can fill bare balsa K&B primer follow di rectly paint short process isnt used models prefer harden surface fabric coverings Koverall Super Coy erite silk use filler areas need perfectly smooth Fiberglass surfaces provide surprisingly lightweight cover supplies strength exterior also re quire filling schedule before final color coats extra strengthening provided fi bergiass can sometimes mean reduced structure beneath Pilot sculptures comes time stan dard hobby shop dummy pilots doni fit appli cation Wrong size apparel reasons re jection decide become amateur sculp tors make own materials probably already workshop small blocks bass wood leftover chunks styrene foam Bass wood carves well demands bit deft carv ing skill render psuedo-human likeness An THE LEADER IN COMPETITION NEW 15 DIA 116 NEW PRO SERIES 3 II \ / NEW HIGH TECH AIRFOIL SECTION 10T020% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUEL PROOF HIGH LUSTER FINISH DIAPITCHPRICE 53/34 634 72833/,456 833/,4568 9 4566A77/ 10 6W8W 10 6EW II 4677/7h78 11 5W 11 6EW ll/ 67 12 4W 12 5W 12 56 13 56 14 56 15 56 16 4/N 16 678 RCPYLON RACING SERIES 500 DIA PITCHPRICE 7 SN 5/N 8I 6778 SERIES 400C 86677/7 9 777 W WIDE BLADE EW EXTRA WIDE N NARROW PROPELLERS 4 DESIGN TAILORED HELICAL PITCH DEVELOPEDTOGIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALL THE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW PITCH THP PRICE 66 Iz 7 7 I/ 677 Ia 8 677/a 8 67 678 June 1988 133