IF YOU LEARNED about shaping ribs way did haggling around fuzzy blue outlines 25-cent kit razor blade quickly realized better way razorblade-and-eyeball technique used back 1930 pro duced some extremely odd airfoils spar notches always nibbled little line up spars first efforts better way making ribs involved use templates made stiff manila board Later tried using flatNovember 1990 117 tened metal tin cans Needless say learned some lessons First stiff template helped cutting ribs individually Placing template end stack ribs worked much better could final sand against both tem plates shape ribs between Second shoving two pins big ones through templates ribs secure stack didnt quite job Long thin ma chine screws kept ribs slipsliding around did trick Third surprised find method worked tapered wings tip rib smaller root rib After midlife interlude built no models first real rib-making experience came restoring built-up ribs 1934 Douglas Hardware Gas model see Doc Mathews columns page 46 June 1989 page 52 August 1989 issues Model Aviation ribs %2-sq zigzags making required rib jig dozens little pieces Later building 4-scale model same plane opted sheet ribs Can anyone guess version model elected use spars passed through ribs shown illustrations spars set upper lower rib pro files however method would have much same decided use metal rib templates struck new modern concern such RC airplane ribs re quire thin ply balsa shear web glued faces upper lower spars between rib Installation consists pushing web place clamping couple clothespins feeding thin CyA cyanoacrylate glue joint Since such glue gap-filling spar faces must same plane avoid cockeyed fit husky metal tem plate greatly helps controlling shaping process spar locations metal template used /16 0625 soft aluminum could just well have sheet metal brass aluminum easy work models wing chord 84 chord full scale 14 Id have used Q90-in metal 118 Model Aviation U three- four-inch chord would have required metal /32 thick important point metal template should thick enough impose firm clamping force over length stacked ribs templates should also strong enough dont flutter subjected disc sander Although used power tools including metal-cutting band saw drill press disc/belt sander such equipment isnt neces sary coping saw jewelers saw will will hand-held electric drill hand-cranked drill Sanding hand sim ply takes little longer secret success having flat sur face bottom lower template seats squarely slides freely saw sander table have often used coun tersunk flat-headed machine bolts case threaded some A-in brazing rod 6/32 end soldered very thin brass discs end template act bolt heads system offers final advantage smash wing metal template al ways ready whether repairs making new wing example first metal templates 1930s Feinberg Com mercial Forty years later hunted out use building another Construction following building se quence keyed accompanying photo graphs A The finished product stack identi cal ribs spar locations perfect alignment homemade through-bolts fashioned threading A-in brazing rod 6/32 end Note relief chamfer bottom template inset bolt head flush fit Its important bottom stack flat B Trace draw rib pattern bond paper adhere smoothly tem plate metal rubber cement sure metal clean dry extend just outside layout lines Also punch retaining screw holes holes will used clamp rib stack try place near enough trailing edge template wont flutter during sanding D second piece aluminum sand wiched between layout rib piece Y16 hardwood plywood Short sheet metal screws secure three pieces Use /16 drill open up spar opening cor ners resulting relief corners helps later filing openings E With templates plywood firmly clamped remove excess metal fluted router bit works well type bit also works well clearing spar notches ribs F No router bit Use twist drill being careful stay within lines G A band saw jigsaw coping saw may used cut templates base piece rough shape H A disc sander bit filing sand ing will bring templates final air foil shape C Center-punch corners spar plywood base can now discard notches openings dimple will Continued page 120 November 1990 119 __________________________________________________________ NEW 4 ES 100 THP DESIGN TAILORED HELICAL PITCH DEVELOPEOTO GIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALLTHE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW DIA PITCH THP PRICE 1266I,77A8 13677/z8 146778 1567 16678 NEW PRO SERIES 3 NEW HIGH TECH AIRFOIL SECTION lOTO 20% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUELPROOFHIGH LUSTER FINISH DIAPITCHPRICE 53/i34 634 72833A456 8334568 94566A77k 1045667 106W8W 106EW 114677/7/,78 IISW II6EW 11/67 124W 12SW 1256 1356 1456 1556 164N 16676 ed Use small square file finish spar openings notches Test fit using piece scrap spar material steel block clamped vise acts file stop Note metal screws have replaced 6-32 machine screws J Stack rib blanks edge end against L-shaped backup blocks drill through stack first long screw trailing edge tips will trimmed after initial wing assembly K With long bolt through rib stack drill second bolt hole its vi tal avoid slippage displacement L With both long bolts secure drill out spar hole notch finish file Push short stub length spar material ensure against shifting long bolt ends can trimmed off flush nut convenience M Insert least spar stub se curity youre ready saw ribs rough contour Keep bit oversize never undersize N The rough-cut rib stack can now sanded final shape trick both saw ing sanding keep stack per fectly vertical canting Good light ing helps Listen carefully sound sander hitting metal have itdurable accurate metal templates will ensure perfect wing airfoil hand future repair reproduction SAGMAAILehmberg Continued page 78 ette IN contest received good cover age San Antonio Evening News Read ers paper learned team mem bers hosted King Leopold m Belgium attending another contest country SAGMAA also assisted promoting movie Men Wings included parade float static dynamic dem onstration Stinson Field San Antonio municipal airport As aviation movie buffs will recall Wings about training military pilots Just few years later number San Antonio boys partic ipated promotion duplicate filmed action served Army Air Corps Later still some SAG MAA members served Army Air Force United States Air Force like Dutch Sluder strong beginning NAA-SAGMAA alliance Goals met surpassed organiza tional meeting held end 1938 ca pable set officers headed Pressler elected 12-point program adopted 1939 Pressler overloaded work requiring organizational talents both SAGMAA Southwest Gas Model Association SWGMA regional collective NAA Gas Model Division chapters 12-point program included complet ing schedule model development ex perimentation scheduling open-house meet ings educate public about model avia tion improving management flying activities several locations Yes very good year Southwest Gas Model Association met Dallas early 1939 plan years contest schedule first meet slated Abilene May 14 followed San Antonio May 28 Houston June 11 Fort Worth June 25 Mineral Wells July 16 Dallas July 30 Corpus Christi Au gust 13 Waco August 27 Wichita Falls September 3 Austin tentatively scheduled August 13 same day Corpus Christi contest Obviously NAA Gas Model Chapters increased number force Youll notice al case two weeks rest pro vided between contests repair per haps SWGMA 1939 contest season well publicized local merchants ganizations such Exchange Clubs generous prize money fact end 1941 much thousand dollars available prizes SAGMAA coming nearly popular San Anto nio Missions ball club Texas League San Antonio still counted Herb Fisher Bob Rickard Orin Anderson Willie Ng Anton Heisler Percy Cockrell Alfred Person among its prominent model builders 1939 Carl Jonas Jack Harding Bob Sedgewick becoming competi tive though continued sport fly reg ularly Kelly Among newer members Joe Borden JA Carney son Jim Bill Hewgley Clyde Stokes Younger SAGMAA members making Rubber model scene over Thomas Jef ferson High School drill field Jack Goebel WL Vavricka Buddy Frazier Toddy McQuatters Hilton Mollenhauer Charles Barron Alfred Lehmberg large mowed field single small tree center excellent Rubber Free Flight tree course attracted models like magnet held con tests prevailing wind prevailed south un less found lift models generally stayed over field lift planes usu ally went quite high After passing over few nearby houses open coun try mesquite cactus diamondbacks seemed stretch way North Pole Before got know keeper castle lived campus fam ily ships landing roof Continued page 185 120 Model Aviation THE LEADER IN COMPETITION PROPELLERS 4 fI RC PYLON RACING SERIES 500 DIAPITCH PRICE 7SN 5N 8I67A7I8 SERIES 400C 86/,677/a7 977I7 W WIDE BLADE EW EXTRA WIDE N NARROW
Edition: Model Aviation - 1990/11
Page Numbers: 117, 118, 119, 120
IF YOU LEARNED about shaping ribs way did haggling around fuzzy blue outlines 25-cent kit razor blade quickly realized better way razorblade-and-eyeball technique used back 1930 pro duced some extremely odd airfoils spar notches always nibbled little line up spars first efforts better way making ribs involved use templates made stiff manila board Later tried using flatNovember 1990 117 tened metal tin cans Needless say learned some lessons First stiff template helped cutting ribs individually Placing template end stack ribs worked much better could final sand against both tem plates shape ribs between Second shoving two pins big ones through templates ribs secure stack didnt quite job Long thin ma chine screws kept ribs slipsliding around did trick Third surprised find method worked tapered wings tip rib smaller root rib After midlife interlude built no models first real rib-making experience came restoring built-up ribs 1934 Douglas Hardware Gas model see Doc Mathews columns page 46 June 1989 page 52 August 1989 issues Model Aviation ribs %2-sq zigzags making required rib jig dozens little pieces Later building 4-scale model same plane opted sheet ribs Can anyone guess version model elected use spars passed through ribs shown illustrations spars set upper lower rib pro files however method would have much same decided use metal rib templates struck new modern concern such RC airplane ribs re quire thin ply balsa shear web glued faces upper lower spars between rib Installation consists pushing web place clamping couple clothespins feeding thin CyA cyanoacrylate glue joint Since such glue gap-filling spar faces must same plane avoid cockeyed fit husky metal tem plate greatly helps controlling shaping process spar locations metal template used /16 0625 soft aluminum could just well have sheet metal brass aluminum easy work models wing chord 84 chord full scale 14 Id have used Q90-in metal 118 Model Aviation U three- four-inch chord would have required metal /32 thick important point metal template should thick enough impose firm clamping force over length stacked ribs templates should also strong enough dont flutter subjected disc sander Although used power tools including metal-cutting band saw drill press disc/belt sander such equipment isnt neces sary coping saw jewelers saw will will hand-held electric drill hand-cranked drill Sanding hand sim ply takes little longer secret success having flat sur face bottom lower template seats squarely slides freely saw sander table have often used coun tersunk flat-headed machine bolts case threaded some A-in brazing rod 6/32 end soldered very thin brass discs end template act bolt heads system offers final advantage smash wing metal template al ways ready whether repairs making new wing example first metal templates 1930s Feinberg Com mercial Forty years later hunted out use building another Construction following building se quence keyed accompanying photo graphs A The finished product stack identi cal ribs spar locations perfect alignment homemade through-bolts fashioned threading A-in brazing rod 6/32 end Note relief chamfer bottom template inset bolt head flush fit Its important bottom stack flat B Trace draw rib pattern bond paper adhere smoothly tem plate metal rubber cement sure metal clean dry extend just outside layout lines Also punch retaining screw holes holes will used clamp rib stack try place near enough trailing edge template wont flutter during sanding D second piece aluminum sand wiched between layout rib piece Y16 hardwood plywood Short sheet metal screws secure three pieces Use /16 drill open up spar opening cor ners resulting relief corners helps later filing openings E With templates plywood firmly clamped remove excess metal fluted router bit works well type bit also works well clearing spar notches ribs F No router bit Use twist drill being careful stay within lines G A band saw jigsaw coping saw may used cut templates base piece rough shape H A disc sander bit filing sand ing will bring templates final air foil shape C Center-punch corners spar plywood base can now discard notches openings dimple will Continued page 120 November 1990 119 __________________________________________________________ NEW 4 ES 100 THP DESIGN TAILORED HELICAL PITCH DEVELOPEOTO GIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALLTHE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW DIA PITCH THP PRICE 1266I,77A8 13677/z8 146778 1567 16678 NEW PRO SERIES 3 NEW HIGH TECH AIRFOIL SECTION lOTO 20% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUELPROOFHIGH LUSTER FINISH DIAPITCHPRICE 53/i34 634 72833A456 8334568 94566A77k 1045667 106W8W 106EW 114677/7/,78 IISW II6EW 11/67 124W 12SW 1256 1356 1456 1556 164N 16676 ed Use small square file finish spar openings notches Test fit using piece scrap spar material steel block clamped vise acts file stop Note metal screws have replaced 6-32 machine screws J Stack rib blanks edge end against L-shaped backup blocks drill through stack first long screw trailing edge tips will trimmed after initial wing assembly K With long bolt through rib stack drill second bolt hole its vi tal avoid slippage displacement L With both long bolts secure drill out spar hole notch finish file Push short stub length spar material ensure against shifting long bolt ends can trimmed off flush nut convenience M Insert least spar stub se curity youre ready saw ribs rough contour Keep bit oversize never undersize N The rough-cut rib stack can now sanded final shape trick both saw ing sanding keep stack per fectly vertical canting Good light ing helps Listen carefully sound sander hitting metal have itdurable accurate metal templates will ensure perfect wing airfoil hand future repair reproduction SAGMAAILehmberg Continued page 78 ette IN contest received good cover age San Antonio Evening News Read ers paper learned team mem bers hosted King Leopold m Belgium attending another contest country SAGMAA also assisted promoting movie Men Wings included parade float static dynamic dem onstration Stinson Field San Antonio municipal airport As aviation movie buffs will recall Wings about training military pilots Just few years later number San Antonio boys partic ipated promotion duplicate filmed action served Army Air Corps Later still some SAG MAA members served Army Air Force United States Air Force like Dutch Sluder strong beginning NAA-SAGMAA alliance Goals met surpassed organiza tional meeting held end 1938 ca pable set officers headed Pressler elected 12-point program adopted 1939 Pressler overloaded work requiring organizational talents both SAGMAA Southwest Gas Model Association SWGMA regional collective NAA Gas Model Division chapters 12-point program included complet ing schedule model development ex perimentation scheduling open-house meet ings educate public about model avia tion improving management flying activities several locations Yes very good year Southwest Gas Model Association met Dallas early 1939 plan years contest schedule first meet slated Abilene May 14 followed San Antonio May 28 Houston June 11 Fort Worth June 25 Mineral Wells July 16 Dallas July 30 Corpus Christi Au gust 13 Waco August 27 Wichita Falls September 3 Austin tentatively scheduled August 13 same day Corpus Christi contest Obviously NAA Gas Model Chapters increased number force Youll notice al case two weeks rest pro vided between contests repair per haps SWGMA 1939 contest season well publicized local merchants ganizations such Exchange Clubs generous prize money fact end 1941 much thousand dollars available prizes SAGMAA coming nearly popular San Anto nio Missions ball club Texas League San Antonio still counted Herb Fisher Bob Rickard Orin Anderson Willie Ng Anton Heisler Percy Cockrell Alfred Person among its prominent model builders 1939 Carl Jonas Jack Harding Bob Sedgewick becoming competi tive though continued sport fly reg ularly Kelly Among newer members Joe Borden JA Carney son Jim Bill Hewgley Clyde Stokes Younger SAGMAA members making Rubber model scene over Thomas Jef ferson High School drill field Jack Goebel WL Vavricka Buddy Frazier Toddy McQuatters Hilton Mollenhauer Charles Barron Alfred Lehmberg large mowed field single small tree center excellent Rubber Free Flight tree course attracted models like magnet held con tests prevailing wind prevailed south un less found lift models generally stayed over field lift planes usu ally went quite high After passing over few nearby houses open coun try mesquite cactus diamondbacks seemed stretch way North Pole Before got know keeper castle lived campus fam ily ships landing roof Continued page 185 120 Model Aviation THE LEADER IN COMPETITION PROPELLERS 4 fI RC PYLON RACING SERIES 500 DIAPITCH PRICE 7SN 5N 8I67A7I8 SERIES 400C 86/,677/a7 977I7 W WIDE BLADE EW EXTRA WIDE N NARROW
Edition: Model Aviation - 1990/11
Page Numbers: 117, 118, 119, 120
IF YOU LEARNED about shaping ribs way did haggling around fuzzy blue outlines 25-cent kit razor blade quickly realized better way razorblade-and-eyeball technique used back 1930 pro duced some extremely odd airfoils spar notches always nibbled little line up spars first efforts better way making ribs involved use templates made stiff manila board Later tried using flatNovember 1990 117 tened metal tin cans Needless say learned some lessons First stiff template helped cutting ribs individually Placing template end stack ribs worked much better could final sand against both tem plates shape ribs between Second shoving two pins big ones through templates ribs secure stack didnt quite job Long thin ma chine screws kept ribs slipsliding around did trick Third surprised find method worked tapered wings tip rib smaller root rib After midlife interlude built no models first real rib-making experience came restoring built-up ribs 1934 Douglas Hardware Gas model see Doc Mathews columns page 46 June 1989 page 52 August 1989 issues Model Aviation ribs %2-sq zigzags making required rib jig dozens little pieces Later building 4-scale model same plane opted sheet ribs Can anyone guess version model elected use spars passed through ribs shown illustrations spars set upper lower rib pro files however method would have much same decided use metal rib templates struck new modern concern such RC airplane ribs re quire thin ply balsa shear web glued faces upper lower spars between rib Installation consists pushing web place clamping couple clothespins feeding thin CyA cyanoacrylate glue joint Since such glue gap-filling spar faces must same plane avoid cockeyed fit husky metal tem plate greatly helps controlling shaping process spar locations metal template used /16 0625 soft aluminum could just well have sheet metal brass aluminum easy work models wing chord 84 chord full scale 14 Id have used Q90-in metal 118 Model Aviation U three- four-inch chord would have required metal /32 thick important point metal template should thick enough impose firm clamping force over length stacked ribs templates should also strong enough dont flutter subjected disc sander Although used power tools including metal-cutting band saw drill press disc/belt sander such equipment isnt neces sary coping saw jewelers saw will will hand-held electric drill hand-cranked drill Sanding hand sim ply takes little longer secret success having flat sur face bottom lower template seats squarely slides freely saw sander table have often used coun tersunk flat-headed machine bolts case threaded some A-in brazing rod 6/32 end soldered very thin brass discs end template act bolt heads system offers final advantage smash wing metal template al ways ready whether repairs making new wing example first metal templates 1930s Feinberg Com mercial Forty years later hunted out use building another Construction following building se quence keyed accompanying photo graphs A The finished product stack identi cal ribs spar locations perfect alignment homemade through-bolts fashioned threading A-in brazing rod 6/32 end Note relief chamfer bottom template inset bolt head flush fit Its important bottom stack flat B Trace draw rib pattern bond paper adhere smoothly tem plate metal rubber cement sure metal clean dry extend just outside layout lines Also punch retaining screw holes holes will used clamp rib stack try place near enough trailing edge template wont flutter during sanding D second piece aluminum sand wiched between layout rib piece Y16 hardwood plywood Short sheet metal screws secure three pieces Use /16 drill open up spar opening cor ners resulting relief corners helps later filing openings E With templates plywood firmly clamped remove excess metal fluted router bit works well type bit also works well clearing spar notches ribs F No router bit Use twist drill being careful stay within lines G A band saw jigsaw coping saw may used cut templates base piece rough shape H A disc sander bit filing sand ing will bring templates final air foil shape C Center-punch corners spar plywood base can now discard notches openings dimple will Continued page 120 November 1990 119 __________________________________________________________ NEW 4 ES 100 THP DESIGN TAILORED HELICAL PITCH DEVELOPEOTO GIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALLTHE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW DIA PITCH THP PRICE 1266I,77A8 13677/z8 146778 1567 16678 NEW PRO SERIES 3 NEW HIGH TECH AIRFOIL SECTION lOTO 20% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUELPROOFHIGH LUSTER FINISH DIAPITCHPRICE 53/i34 634 72833A456 8334568 94566A77k 1045667 106W8W 106EW 114677/7/,78 IISW II6EW 11/67 124W 12SW 1256 1356 1456 1556 164N 16676 ed Use small square file finish spar openings notches Test fit using piece scrap spar material steel block clamped vise acts file stop Note metal screws have replaced 6-32 machine screws J Stack rib blanks edge end against L-shaped backup blocks drill through stack first long screw trailing edge tips will trimmed after initial wing assembly K With long bolt through rib stack drill second bolt hole its vi tal avoid slippage displacement L With both long bolts secure drill out spar hole notch finish file Push short stub length spar material ensure against shifting long bolt ends can trimmed off flush nut convenience M Insert least spar stub se curity youre ready saw ribs rough contour Keep bit oversize never undersize N The rough-cut rib stack can now sanded final shape trick both saw ing sanding keep stack per fectly vertical canting Good light ing helps Listen carefully sound sander hitting metal have itdurable accurate metal templates will ensure perfect wing airfoil hand future repair reproduction SAGMAAILehmberg Continued page 78 ette IN contest received good cover age San Antonio Evening News Read ers paper learned team mem bers hosted King Leopold m Belgium attending another contest country SAGMAA also assisted promoting movie Men Wings included parade float static dynamic dem onstration Stinson Field San Antonio municipal airport As aviation movie buffs will recall Wings about training military pilots Just few years later number San Antonio boys partic ipated promotion duplicate filmed action served Army Air Corps Later still some SAG MAA members served Army Air Force United States Air Force like Dutch Sluder strong beginning NAA-SAGMAA alliance Goals met surpassed organiza tional meeting held end 1938 ca pable set officers headed Pressler elected 12-point program adopted 1939 Pressler overloaded work requiring organizational talents both SAGMAA Southwest Gas Model Association SWGMA regional collective NAA Gas Model Division chapters 12-point program included complet ing schedule model development ex perimentation scheduling open-house meet ings educate public about model avia tion improving management flying activities several locations Yes very good year Southwest Gas Model Association met Dallas early 1939 plan years contest schedule first meet slated Abilene May 14 followed San Antonio May 28 Houston June 11 Fort Worth June 25 Mineral Wells July 16 Dallas July 30 Corpus Christi Au gust 13 Waco August 27 Wichita Falls September 3 Austin tentatively scheduled August 13 same day Corpus Christi contest Obviously NAA Gas Model Chapters increased number force Youll notice al case two weeks rest pro vided between contests repair per haps SWGMA 1939 contest season well publicized local merchants ganizations such Exchange Clubs generous prize money fact end 1941 much thousand dollars available prizes SAGMAA coming nearly popular San Anto nio Missions ball club Texas League San Antonio still counted Herb Fisher Bob Rickard Orin Anderson Willie Ng Anton Heisler Percy Cockrell Alfred Person among its prominent model builders 1939 Carl Jonas Jack Harding Bob Sedgewick becoming competi tive though continued sport fly reg ularly Kelly Among newer members Joe Borden JA Carney son Jim Bill Hewgley Clyde Stokes Younger SAGMAA members making Rubber model scene over Thomas Jef ferson High School drill field Jack Goebel WL Vavricka Buddy Frazier Toddy McQuatters Hilton Mollenhauer Charles Barron Alfred Lehmberg large mowed field single small tree center excellent Rubber Free Flight tree course attracted models like magnet held con tests prevailing wind prevailed south un less found lift models generally stayed over field lift planes usu ally went quite high After passing over few nearby houses open coun try mesquite cactus diamondbacks seemed stretch way North Pole Before got know keeper castle lived campus fam ily ships landing roof Continued page 185 120 Model Aviation THE LEADER IN COMPETITION PROPELLERS 4 fI RC PYLON RACING SERIES 500 DIAPITCH PRICE 7SN 5N 8I67A7I8 SERIES 400C 86/,677/a7 977I7 W WIDE BLADE EW EXTRA WIDE N NARROW
Edition: Model Aviation - 1990/11
Page Numbers: 117, 118, 119, 120
IF YOU LEARNED about shaping ribs way did haggling around fuzzy blue outlines 25-cent kit razor blade quickly realized better way razorblade-and-eyeball technique used back 1930 pro duced some extremely odd airfoils spar notches always nibbled little line up spars first efforts better way making ribs involved use templates made stiff manila board Later tried using flatNovember 1990 117 tened metal tin cans Needless say learned some lessons First stiff template helped cutting ribs individually Placing template end stack ribs worked much better could final sand against both tem plates shape ribs between Second shoving two pins big ones through templates ribs secure stack didnt quite job Long thin ma chine screws kept ribs slipsliding around did trick Third surprised find method worked tapered wings tip rib smaller root rib After midlife interlude built no models first real rib-making experience came restoring built-up ribs 1934 Douglas Hardware Gas model see Doc Mathews columns page 46 June 1989 page 52 August 1989 issues Model Aviation ribs %2-sq zigzags making required rib jig dozens little pieces Later building 4-scale model same plane opted sheet ribs Can anyone guess version model elected use spars passed through ribs shown illustrations spars set upper lower rib pro files however method would have much same decided use metal rib templates struck new modern concern such RC airplane ribs re quire thin ply balsa shear web glued faces upper lower spars between rib Installation consists pushing web place clamping couple clothespins feeding thin CyA cyanoacrylate glue joint Since such glue gap-filling spar faces must same plane avoid cockeyed fit husky metal tem plate greatly helps controlling shaping process spar locations metal template used /16 0625 soft aluminum could just well have sheet metal brass aluminum easy work models wing chord 84 chord full scale 14 Id have used Q90-in metal 118 Model Aviation U three- four-inch chord would have required metal /32 thick important point metal template should thick enough impose firm clamping force over length stacked ribs templates should also strong enough dont flutter subjected disc sander Although used power tools including metal-cutting band saw drill press disc/belt sander such equipment isnt neces sary coping saw jewelers saw will will hand-held electric drill hand-cranked drill Sanding hand sim ply takes little longer secret success having flat sur face bottom lower template seats squarely slides freely saw sander table have often used coun tersunk flat-headed machine bolts case threaded some A-in brazing rod 6/32 end soldered very thin brass discs end template act bolt heads system offers final advantage smash wing metal template al ways ready whether repairs making new wing example first metal templates 1930s Feinberg Com mercial Forty years later hunted out use building another Construction following building se quence keyed accompanying photo graphs A The finished product stack identi cal ribs spar locations perfect alignment homemade through-bolts fashioned threading A-in brazing rod 6/32 end Note relief chamfer bottom template inset bolt head flush fit Its important bottom stack flat B Trace draw rib pattern bond paper adhere smoothly tem plate metal rubber cement sure metal clean dry extend just outside layout lines Also punch retaining screw holes holes will used clamp rib stack try place near enough trailing edge template wont flutter during sanding D second piece aluminum sand wiched between layout rib piece Y16 hardwood plywood Short sheet metal screws secure three pieces Use /16 drill open up spar opening cor ners resulting relief corners helps later filing openings E With templates plywood firmly clamped remove excess metal fluted router bit works well type bit also works well clearing spar notches ribs F No router bit Use twist drill being careful stay within lines G A band saw jigsaw coping saw may used cut templates base piece rough shape H A disc sander bit filing sand ing will bring templates final air foil shape C Center-punch corners spar plywood base can now discard notches openings dimple will Continued page 120 November 1990 119 __________________________________________________________ NEW 4 ES 100 THP DESIGN TAILORED HELICAL PITCH DEVELOPEOTO GIVE MAXIMUM THRUST AT 4 CYCLE ENGINE RPM ALLTHE LATEST TECHNIQUES USED ON OUR PRO SERIES 3 SEE BELOW DIA PITCH THP PRICE 1266I,77A8 13677/z8 146778 1567 16678 NEW PRO SERIES 3 NEW HIGH TECH AIRFOIL SECTION lOTO 20% INCREASE IN THRUST MFG OF SELECT HARD MAPLE WOOD WILL NOT FATIGUE LIKE SYNTHETICS FUELPROOFHIGH LUSTER FINISH DIAPITCHPRICE 53/i34 634 72833A456 8334568 94566A77k 1045667 106W8W 106EW 114677/7/,78 IISW II6EW 11/67 124W 12SW 1256 1356 1456 1556 164N 16676 ed Use small square file finish spar openings notches Test fit using piece scrap spar material steel block clamped vise acts file stop Note metal screws have replaced 6-32 machine screws J Stack rib blanks edge end against L-shaped backup blocks drill through stack first long screw trailing edge tips will trimmed after initial wing assembly K With long bolt through rib stack drill second bolt hole its vi tal avoid slippage displacement L With both long bolts secure drill out spar hole notch finish file Push short stub length spar material ensure against shifting long bolt ends can trimmed off flush nut convenience M Insert least spar stub se curity youre ready saw ribs rough contour Keep bit oversize never undersize N The rough-cut rib stack can now sanded final shape trick both saw ing sanding keep stack per fectly vertical canting Good light ing helps Listen carefully sound sander hitting metal have itdurable accurate metal templates will ensure perfect wing airfoil hand future repair reproduction SAGMAAILehmberg Continued page 78 ette IN contest received good cover age San Antonio Evening News Read ers paper learned team mem bers hosted King Leopold m Belgium attending another contest country SAGMAA also assisted promoting movie Men Wings included parade float static dynamic dem onstration Stinson Field San Antonio municipal airport As aviation movie buffs will recall Wings about training military pilots Just few years later number San Antonio boys partic ipated promotion duplicate filmed action served Army Air Corps Later still some SAG MAA members served Army Air Force United States Air Force like Dutch Sluder strong beginning NAA-SAGMAA alliance Goals met surpassed organiza tional meeting held end 1938 ca pable set officers headed Pressler elected 12-point program adopted 1939 Pressler overloaded work requiring organizational talents both SAGMAA Southwest Gas Model Association SWGMA regional collective NAA Gas Model Division chapters 12-point program included complet ing schedule model development ex perimentation scheduling open-house meet ings educate public about model avia tion improving management flying activities several locations Yes very good year Southwest Gas Model Association met Dallas early 1939 plan years contest schedule first meet slated Abilene May 14 followed San Antonio May 28 Houston June 11 Fort Worth June 25 Mineral Wells July 16 Dallas July 30 Corpus Christi Au gust 13 Waco August 27 Wichita Falls September 3 Austin tentatively scheduled August 13 same day Corpus Christi contest Obviously NAA Gas Model Chapters increased number force Youll notice al case two weeks rest pro vided between contests repair per haps SWGMA 1939 contest season well publicized local merchants ganizations such Exchange Clubs generous prize money fact end 1941 much thousand dollars available prizes SAGMAA coming nearly popular San Anto nio Missions ball club Texas League San Antonio still counted Herb Fisher Bob Rickard Orin Anderson Willie Ng Anton Heisler Percy Cockrell Alfred Person among its prominent model builders 1939 Carl Jonas Jack Harding Bob Sedgewick becoming competi tive though continued sport fly reg ularly Kelly Among newer members Joe Borden JA Carney son Jim Bill Hewgley Clyde Stokes Younger SAGMAA members making Rubber model scene over Thomas Jef ferson High School drill field Jack Goebel WL Vavricka Buddy Frazier Toddy McQuatters Hilton Mollenhauer Charles Barron Alfred Lehmberg large mowed field single small tree center excellent Rubber Free Flight tree course attracted models like magnet held con tests prevailing wind prevailed south un less found lift models generally stayed over field lift planes usu ally went quite high After passing over few nearby houses open coun try mesquite cactus diamondbacks seemed stretch way North Pole Before got know keeper castle lived campus fam ily ships landing roof Continued page 185 120 Model Aviation THE LEADER IN COMPETITION PROPELLERS 4 fI RC PYLON RACING SERIES 500 DIAPITCH PRICE 7SN 5N 8I67A7I8 SERIES 400C 86/,677/a7 977I7 W WIDE BLADE EW EXTRA WIDE N NARROW