DON Abbott Stillwater Oklahoma questions dimensions shown some indoor model plans really what used quote Dons remark hard visualize being able cut measure balsa precisely Dons reference spars specified being tapered 060 sq 030 sq wing ribs dimensioned 030 X 020 cross-section Yes Don really can done old-timers would rou tinely cut spars dimensions specified plan sheets often worked eye achieve results takes practice simple spar no taper can cut using straightedge sharp knife shown photo make spar simple taper piece tapered width other side strip being uniform thickness largely matter practice two areas proper cutting technique positioning straightedge Four items should stressed regard procedure First straight edge must held firmly exact position required make desired size spar Note straightedge no longer parallel edge balsa sheet canted produce desired amount taper Second knife blade must very sharp Third make cut series two three light cuts instead trying use mighty slash deed Finally flat part blade must parallel straightedge maximum spar strength important wood grain parallel edge balsa sheet Also new sheet balsa make trim cut absolutely sure edge Continued page 114 Ribs produced curved tempiate sharp kniTe KflITO must heid straightno slantand successive iight cuts made response non-indoor readers question anyone couid cut accurateiy exoticaiiy-diniensioned pieces wood Bud says routine such buiiders taiks about methodslike straightedges knifes us Rejoiceye editor chickens May1979 47 -MAMMOTH SCALERSWe have engine mounts WEBRA 91 SUEVA 15 MOKI 15 QUADRA engines 9 plus complete line mufflers Also available nifty throttle control unit QUADRA engine Write illustrated catalog prices Sold DIRECT ORDER ONLY Immediate shipping orders Quarter Headquarters PO BOX 12321San francisco Ca 94112 1 ScaleCUSTOM TUNED ENGINES 1931 Gee Bee Super Sportster General Arrange- COMPETITION ACCESSORIES ment Drawing Cos 049/051 Specialists By For brochure send 15c stamp Catalog 25c W T Bill Given Kustom Kraltsmanship Brochure MODERNISTIC MODELS Box 2599 Laguna Hills CA 92853 PO BOX 6974 ALBUG NM 87197 714 830-5162 learn loop fly around say hold breath close eyes pull full up hope will learn nothing learn loop properly first learn wingover perform wingover wait until wind tail plane let wind help maintain line tension during ma neuver pull up climb Neutralize let plane continue fly across circle until dives across other side pull out up Work wingover until can get right over head make pull-out same height entered maneuver Now ready loop another wingover time turn airplane loop Now wasnt easy Now just tighten up loops little joy looping immense overdo time loop put turn twist lines After six eight loops controls will beoome stiff Always unwind loops after flight perform consecutive loops just relax up control time plane climbing vertically Gravity tends pull loop lower must adjust So now can fly precise altitudes crisp wingovers consecutive loops already accomplished pilot people satisfied ever want get stunt flying combat just know can master control-line flying perform stunt plane capable will want rise greatest challenge control-line flying learning fly inverted challenge learning fly inverted has proven too much fliers catch course controls reversed inverted Down up up down traditional method learning fly inverted half loop fly inverted problem method first exposure inverted flight has begun plane flying slow poor line tension No wonder failures people give up better way Impress brain words get trouble pull full down have phrase memorized ready try fly inverted Flying inverted should begin wingover plane overhead pull down will come out flying inverted fast healthy course will panic immediately full down will come back out flying right side up Keep stretching out length inverted flight wont long until can fly laps inverted can work holding precise altitudes Once have mastered inverted flight freedom entire control-line hemi sphere yours AMA rule book lists stunts used oompetition presents good challenges mastered once have learned fly inverted everything else easy happy crashes FF Indoor/Tenny continued page 47 sheet straight possible Otherwise spar cut will tapered way didnt intend After spar cut edge no longer parallel grain cut another tapered piece Fig up sheet before cutting next spar Double taper harder doubletapered spar mentioned above achieved two steps First sheet balsa painstakingly sanded proper taper along its entire length second taper created cutting tapered piece tapered sheet just simpler spars Dont forget even-up sheet between spar cuts keep grain parallel length spar present-day fliers have decided double-tapered spar really necessary place except prop spars approach assume up- down-loads wing stabilizer rep resent maximum conditions stress spar thickness front back spar weight can minimized seems true except conditions such collisions steering Another factor enters spar sizes Before indoor models braced wing spars supported entire flight stress point maximum stress needs stronger junction between wing post wing spar Spar loading progressively lower nearer wing tips spars tapering maximum wing post minimum tip What about braced wings Fig 2 shows front view simple wing bracing scheme Since cabane bracing wires transfer much flight loads directly wing post wing spar supported three points Only flight loads between points B Fig 2 can now cause spar stress Consequently can see strongest points wing should dihedral joint bracing point simple dihedral used Fig 3 Therefore spar needs tapered smaller both directions support points common compromise make spar same depth between wing post support point tapered toward tips obviously easier make such wing spar four piecestwo pieces between wing post dihedral joint piece tip proper kind splice use shown Fig 4 sometimes referred scarf splice know shown both straight spars dihedral joint Measuring Balsa Once spars cut can measured just like other structural member similar sizeuse machinists micrometer caliper dial indicator caliper Just use delicate touch avoid crushing spar method getting right touch slowly close calipers moving wood back forth between jaws As soon some drag felt wood take reading little practice will enable make very repeatable measurements Another photo shows way cut ribs using curved template Once again sharp knife very important also important blade tangent curve Fig 5 observed pressure cutting will often stress rib change curvature Just spars ribs can tapered case easy imagine maximum stress center rib logically rib should wider center can accomplished using two templates Fig 6 different degree curvature major place such extremes 114 Model Aviation RIE IIRD## W/agspEa sgs NEW 79 CATALOG $100 COMPLETE GUIDE OF RUBBER MODEL SUPPLIES New PEANur PEOPLE P 0 BOX 2498 -MA PH LA MESA CALIF 92041 ONE 714 469-8675 714 442-4636 2 Contests Coming some areas indoor activity consists monthly contests other areas may have two major contests Often monthly activity serves warm-up big contest just before outdoor flying season arrives Tullahoma Alabama will contest Motlow College April 11979 No contact man given announcement appeared FFFLiar new enjoyable news letter Bill Mathews 311 Poinciana Drive Birmingham AL 35209 ph 879 5550 Perhaps Bill can furnish info Meanwhile cold snowy land Chicago 6th Annual Midwestern States Indoor Free Flight Championships slated April 2122 1979 Held Madison St Armory 9 am 5 pm both days meet has following events Paper Stick Indoor Stick Indoor Cabin FAI Indoor Saturday April 21 HLG Pennyplane Novice PP Manhattan Cabin Pea nut Scale AMA Scale April 22 Trophies will given third place addition perpetual trophy cups high point champions age class Wally Simmers Cup awarded high time HLG regardless age Contact Chuck Markos 1106 Montgomery Dr Deerfield IL ph 321 9459225 Bud Tenny PO Box 545 Richardson TX 75080 Sno Paulo Brazil quote official announcement Wishes good thermals everybody Sandman 300 Nat Antoniolis Sandman 300 held both Gas records several years ago period several years fact records never broken merely wiped out rules changes its clip-on floats scored better-than-average take trophies VTO events make model fashionable Nat would shorten distance between wing tail 18 16 inches move fin aft stabilizer fashion lengthen nose compen sate corresponding rearward CG shift reduce stabilizer area 40% 35% eliminate rear wing spars caution suggestions have tested gather wing oonstruction popular highly effective web-and-flange spar about stiff strong its weight best can devised strip-stock diagonals almost effective enhancing torsional rigidity full-blown geodetic unionjack structure yet easier build Multiple top- surface spars up front prevent tissue-sag preserve uniform albeit rather angular airfoil section angular airfoils fly better Lanzo Korda others demonstrated third century ago Unlim-Mulvi As result overwhelming enthusiasm generated first Unlimited Mulvihill event held conjunction 1978 US Free Flight Champs event will repeated annually event sudden-death flight contest AMArule Mulvihill rubber-power models unlimited max Flights must made between 600 nm 620 Saturday May 26 Wing tail surfaces must either solid sheet framed construction covered both sides Motors must fully enclosed Models must weigh least 70 grams rubber 40 grams Commercially made plastic props permitted Awards will perpetual trophy replaced permanent end cycle certificates contestants special recognition some sort top Juniors Seniors Proxy flying permitted Timekeepers may move around foot extent necessary keep model being obscured local ob structions site Otherwise AMA rules apply Registration fee $200 Open mem bers Juniors Seniors free Registra tion consists supplying file card contestants name address paying fee Contestants must registered before flying Pre-registration refundable urged send sponsor intrepid columnist Mini Twin Fin its first six months competition Bob Whites P-30 has racked May1979 115 used wide wing chords FAI FF Duration/Mouser Indoor models weight saving continued page 49 relatively important smaller models
Edition: Model Aviation - 1979/05
Page Numbers: 47, 114, 115
DON Abbott Stillwater Oklahoma questions dimensions shown some indoor model plans really what used quote Dons remark hard visualize being able cut measure balsa precisely Dons reference spars specified being tapered 060 sq 030 sq wing ribs dimensioned 030 X 020 cross-section Yes Don really can done old-timers would rou tinely cut spars dimensions specified plan sheets often worked eye achieve results takes practice simple spar no taper can cut using straightedge sharp knife shown photo make spar simple taper piece tapered width other side strip being uniform thickness largely matter practice two areas proper cutting technique positioning straightedge Four items should stressed regard procedure First straight edge must held firmly exact position required make desired size spar Note straightedge no longer parallel edge balsa sheet canted produce desired amount taper Second knife blade must very sharp Third make cut series two three light cuts instead trying use mighty slash deed Finally flat part blade must parallel straightedge maximum spar strength important wood grain parallel edge balsa sheet Also new sheet balsa make trim cut absolutely sure edge Continued page 114 Ribs produced curved tempiate sharp kniTe KflITO must heid straightno slantand successive iight cuts made response non-indoor readers question anyone couid cut accurateiy exoticaiiy-diniensioned pieces wood Bud says routine such buiiders taiks about methodslike straightedges knifes us Rejoiceye editor chickens May1979 47 -MAMMOTH SCALERSWe have engine mounts WEBRA 91 SUEVA 15 MOKI 15 QUADRA engines 9 plus complete line mufflers Also available nifty throttle control unit QUADRA engine Write illustrated catalog prices Sold DIRECT ORDER ONLY Immediate shipping orders Quarter Headquarters PO BOX 12321San francisco Ca 94112 1 ScaleCUSTOM TUNED ENGINES 1931 Gee Bee Super Sportster General Arrange- COMPETITION ACCESSORIES ment Drawing Cos 049/051 Specialists By For brochure send 15c stamp Catalog 25c W T Bill Given Kustom Kraltsmanship Brochure MODERNISTIC MODELS Box 2599 Laguna Hills CA 92853 PO BOX 6974 ALBUG NM 87197 714 830-5162 learn loop fly around say hold breath close eyes pull full up hope will learn nothing learn loop properly first learn wingover perform wingover wait until wind tail plane let wind help maintain line tension during ma neuver pull up climb Neutralize let plane continue fly across circle until dives across other side pull out up Work wingover until can get right over head make pull-out same height entered maneuver Now ready loop another wingover time turn airplane loop Now wasnt easy Now just tighten up loops little joy looping immense overdo time loop put turn twist lines After six eight loops controls will beoome stiff Always unwind loops after flight perform consecutive loops just relax up control time plane climbing vertically Gravity tends pull loop lower must adjust So now can fly precise altitudes crisp wingovers consecutive loops already accomplished pilot people satisfied ever want get stunt flying combat just know can master control-line flying perform stunt plane capable will want rise greatest challenge control-line flying learning fly inverted challenge learning fly inverted has proven too much fliers catch course controls reversed inverted Down up up down traditional method learning fly inverted half loop fly inverted problem method first exposure inverted flight has begun plane flying slow poor line tension No wonder failures people give up better way Impress brain words get trouble pull full down have phrase memorized ready try fly inverted Flying inverted should begin wingover plane overhead pull down will come out flying inverted fast healthy course will panic immediately full down will come back out flying right side up Keep stretching out length inverted flight wont long until can fly laps inverted can work holding precise altitudes Once have mastered inverted flight freedom entire control-line hemi sphere yours AMA rule book lists stunts used oompetition presents good challenges mastered once have learned fly inverted everything else easy happy crashes FF Indoor/Tenny continued page 47 sheet straight possible Otherwise spar cut will tapered way didnt intend After spar cut edge no longer parallel grain cut another tapered piece Fig up sheet before cutting next spar Double taper harder doubletapered spar mentioned above achieved two steps First sheet balsa painstakingly sanded proper taper along its entire length second taper created cutting tapered piece tapered sheet just simpler spars Dont forget even-up sheet between spar cuts keep grain parallel length spar present-day fliers have decided double-tapered spar really necessary place except prop spars approach assume up- down-loads wing stabilizer rep resent maximum conditions stress spar thickness front back spar weight can minimized seems true except conditions such collisions steering Another factor enters spar sizes Before indoor models braced wing spars supported entire flight stress point maximum stress needs stronger junction between wing post wing spar Spar loading progressively lower nearer wing tips spars tapering maximum wing post minimum tip What about braced wings Fig 2 shows front view simple wing bracing scheme Since cabane bracing wires transfer much flight loads directly wing post wing spar supported three points Only flight loads between points B Fig 2 can now cause spar stress Consequently can see strongest points wing should dihedral joint bracing point simple dihedral used Fig 3 Therefore spar needs tapered smaller both directions support points common compromise make spar same depth between wing post support point tapered toward tips obviously easier make such wing spar four piecestwo pieces between wing post dihedral joint piece tip proper kind splice use shown Fig 4 sometimes referred scarf splice know shown both straight spars dihedral joint Measuring Balsa Once spars cut can measured just like other structural member similar sizeuse machinists micrometer caliper dial indicator caliper Just use delicate touch avoid crushing spar method getting right touch slowly close calipers moving wood back forth between jaws As soon some drag felt wood take reading little practice will enable make very repeatable measurements Another photo shows way cut ribs using curved template Once again sharp knife very important also important blade tangent curve Fig 5 observed pressure cutting will often stress rib change curvature Just spars ribs can tapered case easy imagine maximum stress center rib logically rib should wider center can accomplished using two templates Fig 6 different degree curvature major place such extremes 114 Model Aviation RIE IIRD## W/agspEa sgs NEW 79 CATALOG $100 COMPLETE GUIDE OF RUBBER MODEL SUPPLIES New PEANur PEOPLE P 0 BOX 2498 -MA PH LA MESA CALIF 92041 ONE 714 469-8675 714 442-4636 2 Contests Coming some areas indoor activity consists monthly contests other areas may have two major contests Often monthly activity serves warm-up big contest just before outdoor flying season arrives Tullahoma Alabama will contest Motlow College April 11979 No contact man given announcement appeared FFFLiar new enjoyable news letter Bill Mathews 311 Poinciana Drive Birmingham AL 35209 ph 879 5550 Perhaps Bill can furnish info Meanwhile cold snowy land Chicago 6th Annual Midwestern States Indoor Free Flight Championships slated April 2122 1979 Held Madison St Armory 9 am 5 pm both days meet has following events Paper Stick Indoor Stick Indoor Cabin FAI Indoor Saturday April 21 HLG Pennyplane Novice PP Manhattan Cabin Pea nut Scale AMA Scale April 22 Trophies will given third place addition perpetual trophy cups high point champions age class Wally Simmers Cup awarded high time HLG regardless age Contact Chuck Markos 1106 Montgomery Dr Deerfield IL ph 321 9459225 Bud Tenny PO Box 545 Richardson TX 75080 Sno Paulo Brazil quote official announcement Wishes good thermals everybody Sandman 300 Nat Antoniolis Sandman 300 held both Gas records several years ago period several years fact records never broken merely wiped out rules changes its clip-on floats scored better-than-average take trophies VTO events make model fashionable Nat would shorten distance between wing tail 18 16 inches move fin aft stabilizer fashion lengthen nose compen sate corresponding rearward CG shift reduce stabilizer area 40% 35% eliminate rear wing spars caution suggestions have tested gather wing oonstruction popular highly effective web-and-flange spar about stiff strong its weight best can devised strip-stock diagonals almost effective enhancing torsional rigidity full-blown geodetic unionjack structure yet easier build Multiple top- surface spars up front prevent tissue-sag preserve uniform albeit rather angular airfoil section angular airfoils fly better Lanzo Korda others demonstrated third century ago Unlim-Mulvi As result overwhelming enthusiasm generated first Unlimited Mulvihill event held conjunction 1978 US Free Flight Champs event will repeated annually event sudden-death flight contest AMArule Mulvihill rubber-power models unlimited max Flights must made between 600 nm 620 Saturday May 26 Wing tail surfaces must either solid sheet framed construction covered both sides Motors must fully enclosed Models must weigh least 70 grams rubber 40 grams Commercially made plastic props permitted Awards will perpetual trophy replaced permanent end cycle certificates contestants special recognition some sort top Juniors Seniors Proxy flying permitted Timekeepers may move around foot extent necessary keep model being obscured local ob structions site Otherwise AMA rules apply Registration fee $200 Open mem bers Juniors Seniors free Registra tion consists supplying file card contestants name address paying fee Contestants must registered before flying Pre-registration refundable urged send sponsor intrepid columnist Mini Twin Fin its first six months competition Bob Whites P-30 has racked May1979 115 used wide wing chords FAI FF Duration/Mouser Indoor models weight saving continued page 49 relatively important smaller models
Edition: Model Aviation - 1979/05
Page Numbers: 47, 114, 115
DON Abbott Stillwater Oklahoma questions dimensions shown some indoor model plans really what used quote Dons remark hard visualize being able cut measure balsa precisely Dons reference spars specified being tapered 060 sq 030 sq wing ribs dimensioned 030 X 020 cross-section Yes Don really can done old-timers would rou tinely cut spars dimensions specified plan sheets often worked eye achieve results takes practice simple spar no taper can cut using straightedge sharp knife shown photo make spar simple taper piece tapered width other side strip being uniform thickness largely matter practice two areas proper cutting technique positioning straightedge Four items should stressed regard procedure First straight edge must held firmly exact position required make desired size spar Note straightedge no longer parallel edge balsa sheet canted produce desired amount taper Second knife blade must very sharp Third make cut series two three light cuts instead trying use mighty slash deed Finally flat part blade must parallel straightedge maximum spar strength important wood grain parallel edge balsa sheet Also new sheet balsa make trim cut absolutely sure edge Continued page 114 Ribs produced curved tempiate sharp kniTe KflITO must heid straightno slantand successive iight cuts made response non-indoor readers question anyone couid cut accurateiy exoticaiiy-diniensioned pieces wood Bud says routine such buiiders taiks about methodslike straightedges knifes us Rejoiceye editor chickens May1979 47 -MAMMOTH SCALERSWe have engine mounts WEBRA 91 SUEVA 15 MOKI 15 QUADRA engines 9 plus complete line mufflers Also available nifty throttle control unit QUADRA engine Write illustrated catalog prices Sold DIRECT ORDER ONLY Immediate shipping orders Quarter Headquarters PO BOX 12321San francisco Ca 94112 1 ScaleCUSTOM TUNED ENGINES 1931 Gee Bee Super Sportster General Arrange- COMPETITION ACCESSORIES ment Drawing Cos 049/051 Specialists By For brochure send 15c stamp Catalog 25c W T Bill Given Kustom Kraltsmanship Brochure MODERNISTIC MODELS Box 2599 Laguna Hills CA 92853 PO BOX 6974 ALBUG NM 87197 714 830-5162 learn loop fly around say hold breath close eyes pull full up hope will learn nothing learn loop properly first learn wingover perform wingover wait until wind tail plane let wind help maintain line tension during ma neuver pull up climb Neutralize let plane continue fly across circle until dives across other side pull out up Work wingover until can get right over head make pull-out same height entered maneuver Now ready loop another wingover time turn airplane loop Now wasnt easy Now just tighten up loops little joy looping immense overdo time loop put turn twist lines After six eight loops controls will beoome stiff Always unwind loops after flight perform consecutive loops just relax up control time plane climbing vertically Gravity tends pull loop lower must adjust So now can fly precise altitudes crisp wingovers consecutive loops already accomplished pilot people satisfied ever want get stunt flying combat just know can master control-line flying perform stunt plane capable will want rise greatest challenge control-line flying learning fly inverted challenge learning fly inverted has proven too much fliers catch course controls reversed inverted Down up up down traditional method learning fly inverted half loop fly inverted problem method first exposure inverted flight has begun plane flying slow poor line tension No wonder failures people give up better way Impress brain words get trouble pull full down have phrase memorized ready try fly inverted Flying inverted should begin wingover plane overhead pull down will come out flying inverted fast healthy course will panic immediately full down will come back out flying right side up Keep stretching out length inverted flight wont long until can fly laps inverted can work holding precise altitudes Once have mastered inverted flight freedom entire control-line hemi sphere yours AMA rule book lists stunts used oompetition presents good challenges mastered once have learned fly inverted everything else easy happy crashes FF Indoor/Tenny continued page 47 sheet straight possible Otherwise spar cut will tapered way didnt intend After spar cut edge no longer parallel grain cut another tapered piece Fig up sheet before cutting next spar Double taper harder doubletapered spar mentioned above achieved two steps First sheet balsa painstakingly sanded proper taper along its entire length second taper created cutting tapered piece tapered sheet just simpler spars Dont forget even-up sheet between spar cuts keep grain parallel length spar present-day fliers have decided double-tapered spar really necessary place except prop spars approach assume up- down-loads wing stabilizer rep resent maximum conditions stress spar thickness front back spar weight can minimized seems true except conditions such collisions steering Another factor enters spar sizes Before indoor models braced wing spars supported entire flight stress point maximum stress needs stronger junction between wing post wing spar Spar loading progressively lower nearer wing tips spars tapering maximum wing post minimum tip What about braced wings Fig 2 shows front view simple wing bracing scheme Since cabane bracing wires transfer much flight loads directly wing post wing spar supported three points Only flight loads between points B Fig 2 can now cause spar stress Consequently can see strongest points wing should dihedral joint bracing point simple dihedral used Fig 3 Therefore spar needs tapered smaller both directions support points common compromise make spar same depth between wing post support point tapered toward tips obviously easier make such wing spar four piecestwo pieces between wing post dihedral joint piece tip proper kind splice use shown Fig 4 sometimes referred scarf splice know shown both straight spars dihedral joint Measuring Balsa Once spars cut can measured just like other structural member similar sizeuse machinists micrometer caliper dial indicator caliper Just use delicate touch avoid crushing spar method getting right touch slowly close calipers moving wood back forth between jaws As soon some drag felt wood take reading little practice will enable make very repeatable measurements Another photo shows way cut ribs using curved template Once again sharp knife very important also important blade tangent curve Fig 5 observed pressure cutting will often stress rib change curvature Just spars ribs can tapered case easy imagine maximum stress center rib logically rib should wider center can accomplished using two templates Fig 6 different degree curvature major place such extremes 114 Model Aviation RIE IIRD## W/agspEa sgs NEW 79 CATALOG $100 COMPLETE GUIDE OF RUBBER MODEL SUPPLIES New PEANur PEOPLE P 0 BOX 2498 -MA PH LA MESA CALIF 92041 ONE 714 469-8675 714 442-4636 2 Contests Coming some areas indoor activity consists monthly contests other areas may have two major contests Often monthly activity serves warm-up big contest just before outdoor flying season arrives Tullahoma Alabama will contest Motlow College April 11979 No contact man given announcement appeared FFFLiar new enjoyable news letter Bill Mathews 311 Poinciana Drive Birmingham AL 35209 ph 879 5550 Perhaps Bill can furnish info Meanwhile cold snowy land Chicago 6th Annual Midwestern States Indoor Free Flight Championships slated April 2122 1979 Held Madison St Armory 9 am 5 pm both days meet has following events Paper Stick Indoor Stick Indoor Cabin FAI Indoor Saturday April 21 HLG Pennyplane Novice PP Manhattan Cabin Pea nut Scale AMA Scale April 22 Trophies will given third place addition perpetual trophy cups high point champions age class Wally Simmers Cup awarded high time HLG regardless age Contact Chuck Markos 1106 Montgomery Dr Deerfield IL ph 321 9459225 Bud Tenny PO Box 545 Richardson TX 75080 Sno Paulo Brazil quote official announcement Wishes good thermals everybody Sandman 300 Nat Antoniolis Sandman 300 held both Gas records several years ago period several years fact records never broken merely wiped out rules changes its clip-on floats scored better-than-average take trophies VTO events make model fashionable Nat would shorten distance between wing tail 18 16 inches move fin aft stabilizer fashion lengthen nose compen sate corresponding rearward CG shift reduce stabilizer area 40% 35% eliminate rear wing spars caution suggestions have tested gather wing oonstruction popular highly effective web-and-flange spar about stiff strong its weight best can devised strip-stock diagonals almost effective enhancing torsional rigidity full-blown geodetic unionjack structure yet easier build Multiple top- surface spars up front prevent tissue-sag preserve uniform albeit rather angular airfoil section angular airfoils fly better Lanzo Korda others demonstrated third century ago Unlim-Mulvi As result overwhelming enthusiasm generated first Unlimited Mulvihill event held conjunction 1978 US Free Flight Champs event will repeated annually event sudden-death flight contest AMArule Mulvihill rubber-power models unlimited max Flights must made between 600 nm 620 Saturday May 26 Wing tail surfaces must either solid sheet framed construction covered both sides Motors must fully enclosed Models must weigh least 70 grams rubber 40 grams Commercially made plastic props permitted Awards will perpetual trophy replaced permanent end cycle certificates contestants special recognition some sort top Juniors Seniors Proxy flying permitted Timekeepers may move around foot extent necessary keep model being obscured local ob structions site Otherwise AMA rules apply Registration fee $200 Open mem bers Juniors Seniors free Registra tion consists supplying file card contestants name address paying fee Contestants must registered before flying Pre-registration refundable urged send sponsor intrepid columnist Mini Twin Fin its first six months competition Bob Whites P-30 has racked May1979 115 used wide wing chords FAI FF Duration/Mouser Indoor models weight saving continued page 49 relatively important smaller models