Pybn Racing Dave Lane LAST MONTH talked about fuel tank three mounting holes should usedand installation month lets talk about four room hunk aluminum fuel tankCB Tatone make special mounts feeds for 15s machined flat the important items proper areas have plenty beef motor mount mount should mounting face CB Tatone RNS proper size engine being used R/G Products make mounts 40 mounting Rossi 15 use mount engines used Formula made 15-sized enginesMount motor mount firewall Dont use mount made 29 6-32 screws T-nuts Pay particu 35 because mounts too large lar attention mounting holes engine should slip fit between engine Some mounts come pre mounting rails mount drilled mount pre-drilled rails should flat zero degrees thrust careful drilling pilot holes vertical face back vertical lug face 15s mount vertical face mount 4-40 screws adequate use 6-32s touches firewall should flat least 40s need extra beef MAX THICKNESS AT 25%-30% OF FLAT CHORD/SMALL ANGLE ROUND L E FLAT FIG TYPICAL AIRFOIL 0 GINA L ~~REMOVE REMOVEYAAEXCESS TE FIG 2 EXAMPLE OF PITCH REDUCTION II RASP SAND BOTTOM FLAT EXCEPT LE FIG 3 CARVE PITCH WITH RASP did double-take Ron Schorr told us name given Formula 1Bertkens Brown Bag Minnow Has some thing Bertken packages kitsRon NMPRA prexy 9Q0900 6-32s bold 40s down en gines really pound mount turning maximum rpm have seen 40s shear 4-40s ease 6-32s will shear mount isnt abso lutely square may have grind some material off inside surface rails get proper fit engine sure remove amount necessary try leave deep scratches aluminum guarantee have scratch rails mount will break After removal excess mate rial polish surface 400 600 grit sandpaper Some guys like drill clear ance holes through mount use nuts lock washers machine screws prefer tap motor mount use Allen-head machine screws lock washers problem using nuts washers trying engage nut Continued page 83 DRILL AND TAP FOR 6-32 OR 4-40 MACHINE SCREWS top rpm failure resistance solid mount imperative 15size engines 4-40 screws adequate 40s use 6-32s MOUNT SPINNERFIREWALLSPINNER FIREWALL RING T-NUTSRING 4 4-40 SCREWS632 MACHINEo3/8OR 1/2 SCREWSPLYWOOD MOUNTYOKE Two methods anchoring front mount stop flexing engine running Take care mount square solid April1977 19 DRILL FOR 632 MACHINE SCREWS NEWEST Continuing tradition producing finest balsa kits Guillow offers two famous World War 2 twin-engine jobs have long top requested list B-25 Mitchell won fame 1942 raid Tokyo aircraft carrier USS Hornet V Mosquito fastest its type British Bomber Command Both kits contain full decal sets scale wheels plastic spinners cowls nacelles canopy clear precise planwork other top grade materials Everything included U/control installation Scale U/Control Rugged heavy duty construction stress U/C flying HOT flying two Cox 049 Black Widow engines al flights used Cox 048 Golden Bees th beginner style flying Cox 020 Pee Wees Hobby etoren cany Guillow models Check Yellow Pages nearest area send direct factory adding $150 handling USA. $200 outside USA Send 15 cent folder listing Ituillow model kits 0 : RC Pylon Racing/Lane Continued page 19 screw Usually just isnt enough clearance between mount fuselage accept nuts fingers tweezers same time Formula ships front rails should secured fuselage either spinner ring through plywood yoke mounted fuselage anchoring front mount structure front mount can flex engine running usually worth another 200 400 rpm main thing remember install ing mount fuselage keep square solid Nothing frustrat ing have good strong engine poorly mounted racer wonder turn 17500 rpm body else turning 20000 following information about Midget props written Bob Root QMRC Newsletter belong QMRC havent joined A-Midget organization thought might like find out pros A Important characteristics following list things look modifying props 1 Airfoil shape Based Formula experience blade shouldnt too thick maybe 10% thickness flat bottom except near leading edge thin trailing edge See Fig 1 2 Blade width Time will tell feel racing shapes will work best such narrow Rev-up Top Flite pylon shapes Too wide equals low rpm Too narrow equals slow inefficient top speed ac celeration dont feel tip shape important raked tip rumored reduce flutter problem 3 Pitch diameter will also re quire experimentation 7-5 props seem close measure approxi mately 7 diameter 45 pitch pitch gauge necessity correlation tween prop performance actual size achieved have seen make 7-5 props measured pitch low 42 high 49 optimum prop found air shoot ground rpm 21000 21500 Rossi using tach readings think constant pitch along entire blade best tip pitch can reduced increase rpm Too small diameter equals slow inefficient acceleration Too low pitch equals reduced top speed good acceleration B Modification Steps 1 First sand back hub get equal pitch both blades 2 Next flatten smooth back blades pitch change needed start wider blade narrow material available changing pitch See Fig 2 Remove material leading edge increase pitch trailing edge reduce pitch little material removal goes long way check pitch gauge go half-round wood rasp works best See Fig 3 cause twist blade sanding block tends round airfoil rather produce desired flat bottom 3 Once back smooth equal pitch both blades form airfoil Thin smooth top form leading edge sharp LE good Round somewhat Fig 1 shows typical airfoil 4 If span reduced first now Thin shape tips now 5 Next balance prop removing material front blade will preserve pitch carefully formed back side 6 Run prop engine April 1977 83 Kit No 804 DeHavilland Mu -I V . Mosquito 25% Wing S pan 16840 CMSI Approx Scale 7/16 ARTICLES WANTED Have design youd like have pub lished topic youd like write about tell editor about may worth money fiLttU&I*i PRODUCTS INC 535 DAVISYILLE ROAD OW GROVE PA 19090 658-3900 call CRAP TRAP* does exactlywhat think Crap Trap name purloined model builder Toledo Finally filter keep modern engines truly clean Call itan IMPURITIES FILTRATION SYSTEM want. call Crap Trap Newer sophisticated carburetors pumps very sensitive fine par ticles can get through filters Crap Trap Heres DOUBLE FILTRATIONIncludes two separate filters 100 mesh 007 openIng 120 mesh 004 opening Patent Applied MORE FILTER AREABoth filters cup-shaped greatly increase filter capacity COLOR CODEDFuel must go through larger silver mesh first filter out larger particles through smaller bronze mesh must WATCH IT WORKFilters encased see-through tubing CAN TAKE THE HEATThe extruded Teflon casing can handle temperatures up soo0 F 1 Between Tank 2 Between Fuel con3 Between Muffler Tank No need re move tubing muffler see tank Youve got try great new filter believe Watch action enjoy model its cleaner smoother-running engine note rpm its ballpark fly see works too low cut span put washout reduce pitch tip Use Fig 2 method get wash out outer span prop flutters give worst enemy start over funny noise rpm lower expected equals flutter will plane go slower stand chance having come apart running C Recomniendations Until someone comes up opti mum prop find major break through will trying following props 1 7-SN Rev-Up Thin TE little cleanup Cut span little necessary may best prop running muffler prop am currently using unmodified 2 7-SN Top Flite has little pitch 1 Clean up form good air foil bad airfoil out box rpm still low trim span slightly 3 7-6N Rev-Up has higher pitch 2 Thin clean up cut span may washout tips get rpm up RPM low out box 4 7-5 Rev-Up has blade area will allow bigger pitch changes anyone learns take advantage Ditto 7-5W Top Flite Dave Lane 4477 136th Hawthorne CA 90250 poductreviewproduetreeieWPVOdUCtrCViCWPrOdUCtrCViW Electric Twin Up now twin-engined electric powered RC scale model has seen kit form combination Model Flite England Polks International offer ing Britten/Norman Islander Powered two Model Flite Hummingbird motors pre wired installation spans 50 ins flying weight 3/a lbs nicad cassette pack 96V allows 8- 10-mm flights 30-mm recharge time Kit includes pre covered foam wings aileron cable stalled vacu-formed nacelles hardware pre cut prefab parts Props Cox6/3 spinners Prices Islander kit $6995 twin motor nicad pack $15995 charging monitor $3995 Polks Model-Craft Hobbies Inc 314 Fifth Ave New York NY 10001 producteiewproduetreviCwPtOdUetrCviWPrOdUCtrGVIeW F writing advertisers mention read about MA Goes/Hill Continued page 25 ventional airplane passes down wind upwind 228 210which would have record hap pened same flight So can done Lars Giertz possible improved tracks Houston smaller airplane what George flying good OPS Because lower total drag could did use 9 diameter propeller lets engine rev up bit 22000 get alls well Unfortu nately Lars aileron flutter prob lem early trials suffered dam age during launch No officials times recorded looked very fast must remember smaller air plane faster appears going Lars no throttle airplane arrangement will take really good pilot avoid having such smaller air plane disappear wild blue yonder out control Secing airplane biggest problems setting speed record Art Arros speed model looked good went over hill first flight due getting out controllable sight range Actually didnt have real chance because powered 40 too large Delta planform airplanes have lower 84 Model Aviation
Edition: Model Aviation - 1977/04
Page Numbers: 19, 83, 84
Pybn Racing Dave Lane LAST MONTH talked about fuel tank three mounting holes should usedand installation month lets talk about four room hunk aluminum fuel tankCB Tatone make special mounts feeds for 15s machined flat the important items proper areas have plenty beef motor mount mount should mounting face CB Tatone RNS proper size engine being used R/G Products make mounts 40 mounting Rossi 15 use mount engines used Formula made 15-sized enginesMount motor mount firewall Dont use mount made 29 6-32 screws T-nuts Pay particu 35 because mounts too large lar attention mounting holes engine should slip fit between engine Some mounts come pre mounting rails mount drilled mount pre-drilled rails should flat zero degrees thrust careful drilling pilot holes vertical face back vertical lug face 15s mount vertical face mount 4-40 screws adequate use 6-32s touches firewall should flat least 40s need extra beef MAX THICKNESS AT 25%-30% OF FLAT CHORD/SMALL ANGLE ROUND L E FLAT FIG TYPICAL AIRFOIL 0 GINA L ~~REMOVE REMOVEYAAEXCESS TE FIG 2 EXAMPLE OF PITCH REDUCTION II RASP SAND BOTTOM FLAT EXCEPT LE FIG 3 CARVE PITCH WITH RASP did double-take Ron Schorr told us name given Formula 1Bertkens Brown Bag Minnow Has some thing Bertken packages kitsRon NMPRA prexy 9Q0900 6-32s bold 40s down en gines really pound mount turning maximum rpm have seen 40s shear 4-40s ease 6-32s will shear mount isnt abso lutely square may have grind some material off inside surface rails get proper fit engine sure remove amount necessary try leave deep scratches aluminum guarantee have scratch rails mount will break After removal excess mate rial polish surface 400 600 grit sandpaper Some guys like drill clear ance holes through mount use nuts lock washers machine screws prefer tap motor mount use Allen-head machine screws lock washers problem using nuts washers trying engage nut Continued page 83 DRILL AND TAP FOR 6-32 OR 4-40 MACHINE SCREWS top rpm failure resistance solid mount imperative 15size engines 4-40 screws adequate 40s use 6-32s MOUNT SPINNERFIREWALLSPINNER FIREWALL RING T-NUTSRING 4 4-40 SCREWS632 MACHINEo3/8OR 1/2 SCREWSPLYWOOD MOUNTYOKE Two methods anchoring front mount stop flexing engine running Take care mount square solid April1977 19 DRILL FOR 632 MACHINE SCREWS NEWEST Continuing tradition producing finest balsa kits Guillow offers two famous World War 2 twin-engine jobs have long top requested list B-25 Mitchell won fame 1942 raid Tokyo aircraft carrier USS Hornet V Mosquito fastest its type British Bomber Command Both kits contain full decal sets scale wheels plastic spinners cowls nacelles canopy clear precise planwork other top grade materials Everything included U/control installation Scale U/Control Rugged heavy duty construction stress U/C flying HOT flying two Cox 049 Black Widow engines al flights used Cox 048 Golden Bees th beginner style flying Cox 020 Pee Wees Hobby etoren cany Guillow models Check Yellow Pages nearest area send direct factory adding $150 handling USA. $200 outside USA Send 15 cent folder listing Ituillow model kits 0 : RC Pylon Racing/Lane Continued page 19 screw Usually just isnt enough clearance between mount fuselage accept nuts fingers tweezers same time Formula ships front rails should secured fuselage either spinner ring through plywood yoke mounted fuselage anchoring front mount structure front mount can flex engine running usually worth another 200 400 rpm main thing remember install ing mount fuselage keep square solid Nothing frustrat ing have good strong engine poorly mounted racer wonder turn 17500 rpm body else turning 20000 following information about Midget props written Bob Root QMRC Newsletter belong QMRC havent joined A-Midget organization thought might like find out pros A Important characteristics following list things look modifying props 1 Airfoil shape Based Formula experience blade shouldnt too thick maybe 10% thickness flat bottom except near leading edge thin trailing edge See Fig 1 2 Blade width Time will tell feel racing shapes will work best such narrow Rev-up Top Flite pylon shapes Too wide equals low rpm Too narrow equals slow inefficient top speed ac celeration dont feel tip shape important raked tip rumored reduce flutter problem 3 Pitch diameter will also re quire experimentation 7-5 props seem close measure approxi mately 7 diameter 45 pitch pitch gauge necessity correlation tween prop performance actual size achieved have seen make 7-5 props measured pitch low 42 high 49 optimum prop found air shoot ground rpm 21000 21500 Rossi using tach readings think constant pitch along entire blade best tip pitch can reduced increase rpm Too small diameter equals slow inefficient acceleration Too low pitch equals reduced top speed good acceleration B Modification Steps 1 First sand back hub get equal pitch both blades 2 Next flatten smooth back blades pitch change needed start wider blade narrow material available changing pitch See Fig 2 Remove material leading edge increase pitch trailing edge reduce pitch little material removal goes long way check pitch gauge go half-round wood rasp works best See Fig 3 cause twist blade sanding block tends round airfoil rather produce desired flat bottom 3 Once back smooth equal pitch both blades form airfoil Thin smooth top form leading edge sharp LE good Round somewhat Fig 1 shows typical airfoil 4 If span reduced first now Thin shape tips now 5 Next balance prop removing material front blade will preserve pitch carefully formed back side 6 Run prop engine April 1977 83 Kit No 804 DeHavilland Mu -I V . Mosquito 25% Wing S pan 16840 CMSI Approx Scale 7/16 ARTICLES WANTED Have design youd like have pub lished topic youd like write about tell editor about may worth money fiLttU&I*i PRODUCTS INC 535 DAVISYILLE ROAD OW GROVE PA 19090 658-3900 call CRAP TRAP* does exactlywhat think Crap Trap name purloined model builder Toledo Finally filter keep modern engines truly clean Call itan IMPURITIES FILTRATION SYSTEM want. call Crap Trap Newer sophisticated carburetors pumps very sensitive fine par ticles can get through filters Crap Trap Heres DOUBLE FILTRATIONIncludes two separate filters 100 mesh 007 openIng 120 mesh 004 opening Patent Applied MORE FILTER AREABoth filters cup-shaped greatly increase filter capacity COLOR CODEDFuel must go through larger silver mesh first filter out larger particles through smaller bronze mesh must WATCH IT WORKFilters encased see-through tubing CAN TAKE THE HEATThe extruded Teflon casing can handle temperatures up soo0 F 1 Between Tank 2 Between Fuel con3 Between Muffler Tank No need re move tubing muffler see tank Youve got try great new filter believe Watch action enjoy model its cleaner smoother-running engine note rpm its ballpark fly see works too low cut span put washout reduce pitch tip Use Fig 2 method get wash out outer span prop flutters give worst enemy start over funny noise rpm lower expected equals flutter will plane go slower stand chance having come apart running C Recomniendations Until someone comes up opti mum prop find major break through will trying following props 1 7-SN Rev-Up Thin TE little cleanup Cut span little necessary may best prop running muffler prop am currently using unmodified 2 7-SN Top Flite has little pitch 1 Clean up form good air foil bad airfoil out box rpm still low trim span slightly 3 7-6N Rev-Up has higher pitch 2 Thin clean up cut span may washout tips get rpm up RPM low out box 4 7-5 Rev-Up has blade area will allow bigger pitch changes anyone learns take advantage Ditto 7-5W Top Flite Dave Lane 4477 136th Hawthorne CA 90250 poductreviewproduetreeieWPVOdUCtrCViCWPrOdUCtrCViW Electric Twin Up now twin-engined electric powered RC scale model has seen kit form combination Model Flite England Polks International offer ing Britten/Norman Islander Powered two Model Flite Hummingbird motors pre wired installation spans 50 ins flying weight 3/a lbs nicad cassette pack 96V allows 8- 10-mm flights 30-mm recharge time Kit includes pre covered foam wings aileron cable stalled vacu-formed nacelles hardware pre cut prefab parts Props Cox6/3 spinners Prices Islander kit $6995 twin motor nicad pack $15995 charging monitor $3995 Polks Model-Craft Hobbies Inc 314 Fifth Ave New York NY 10001 producteiewproduetreviCwPtOdUetrCviWPrOdUCtrGVIeW F writing advertisers mention read about MA Goes/Hill Continued page 25 ventional airplane passes down wind upwind 228 210which would have record hap pened same flight So can done Lars Giertz possible improved tracks Houston smaller airplane what George flying good OPS Because lower total drag could did use 9 diameter propeller lets engine rev up bit 22000 get alls well Unfortu nately Lars aileron flutter prob lem early trials suffered dam age during launch No officials times recorded looked very fast must remember smaller air plane faster appears going Lars no throttle airplane arrangement will take really good pilot avoid having such smaller air plane disappear wild blue yonder out control Secing airplane biggest problems setting speed record Art Arros speed model looked good went over hill first flight due getting out controllable sight range Actually didnt have real chance because powered 40 too large Delta planform airplanes have lower 84 Model Aviation
Edition: Model Aviation - 1977/04
Page Numbers: 19, 83, 84
Pybn Racing Dave Lane LAST MONTH talked about fuel tank three mounting holes should usedand installation month lets talk about four room hunk aluminum fuel tankCB Tatone make special mounts feeds for 15s machined flat the important items proper areas have plenty beef motor mount mount should mounting face CB Tatone RNS proper size engine being used R/G Products make mounts 40 mounting Rossi 15 use mount engines used Formula made 15-sized enginesMount motor mount firewall Dont use mount made 29 6-32 screws T-nuts Pay particu 35 because mounts too large lar attention mounting holes engine should slip fit between engine Some mounts come pre mounting rails mount drilled mount pre-drilled rails should flat zero degrees thrust careful drilling pilot holes vertical face back vertical lug face 15s mount vertical face mount 4-40 screws adequate use 6-32s touches firewall should flat least 40s need extra beef MAX THICKNESS AT 25%-30% OF FLAT CHORD/SMALL ANGLE ROUND L E FLAT FIG TYPICAL AIRFOIL 0 GINA L ~~REMOVE REMOVEYAAEXCESS TE FIG 2 EXAMPLE OF PITCH REDUCTION II RASP SAND BOTTOM FLAT EXCEPT LE FIG 3 CARVE PITCH WITH RASP did double-take Ron Schorr told us name given Formula 1Bertkens Brown Bag Minnow Has some thing Bertken packages kitsRon NMPRA prexy 9Q0900 6-32s bold 40s down en gines really pound mount turning maximum rpm have seen 40s shear 4-40s ease 6-32s will shear mount isnt abso lutely square may have grind some material off inside surface rails get proper fit engine sure remove amount necessary try leave deep scratches aluminum guarantee have scratch rails mount will break After removal excess mate rial polish surface 400 600 grit sandpaper Some guys like drill clear ance holes through mount use nuts lock washers machine screws prefer tap motor mount use Allen-head machine screws lock washers problem using nuts washers trying engage nut Continued page 83 DRILL AND TAP FOR 6-32 OR 4-40 MACHINE SCREWS top rpm failure resistance solid mount imperative 15size engines 4-40 screws adequate 40s use 6-32s MOUNT SPINNERFIREWALLSPINNER FIREWALL RING T-NUTSRING 4 4-40 SCREWS632 MACHINEo3/8OR 1/2 SCREWSPLYWOOD MOUNTYOKE Two methods anchoring front mount stop flexing engine running Take care mount square solid April1977 19 DRILL FOR 632 MACHINE SCREWS NEWEST Continuing tradition producing finest balsa kits Guillow offers two famous World War 2 twin-engine jobs have long top requested list B-25 Mitchell won fame 1942 raid Tokyo aircraft carrier USS Hornet V Mosquito fastest its type British Bomber Command Both kits contain full decal sets scale wheels plastic spinners cowls nacelles canopy clear precise planwork other top grade materials Everything included U/control installation Scale U/Control Rugged heavy duty construction stress U/C flying HOT flying two Cox 049 Black Widow engines al flights used Cox 048 Golden Bees th beginner style flying Cox 020 Pee Wees Hobby etoren cany Guillow models Check Yellow Pages nearest area send direct factory adding $150 handling USA. $200 outside USA Send 15 cent folder listing Ituillow model kits 0 : RC Pylon Racing/Lane Continued page 19 screw Usually just isnt enough clearance between mount fuselage accept nuts fingers tweezers same time Formula ships front rails should secured fuselage either spinner ring through plywood yoke mounted fuselage anchoring front mount structure front mount can flex engine running usually worth another 200 400 rpm main thing remember install ing mount fuselage keep square solid Nothing frustrat ing have good strong engine poorly mounted racer wonder turn 17500 rpm body else turning 20000 following information about Midget props written Bob Root QMRC Newsletter belong QMRC havent joined A-Midget organization thought might like find out pros A Important characteristics following list things look modifying props 1 Airfoil shape Based Formula experience blade shouldnt too thick maybe 10% thickness flat bottom except near leading edge thin trailing edge See Fig 1 2 Blade width Time will tell feel racing shapes will work best such narrow Rev-up Top Flite pylon shapes Too wide equals low rpm Too narrow equals slow inefficient top speed ac celeration dont feel tip shape important raked tip rumored reduce flutter problem 3 Pitch diameter will also re quire experimentation 7-5 props seem close measure approxi mately 7 diameter 45 pitch pitch gauge necessity correlation tween prop performance actual size achieved have seen make 7-5 props measured pitch low 42 high 49 optimum prop found air shoot ground rpm 21000 21500 Rossi using tach readings think constant pitch along entire blade best tip pitch can reduced increase rpm Too small diameter equals slow inefficient acceleration Too low pitch equals reduced top speed good acceleration B Modification Steps 1 First sand back hub get equal pitch both blades 2 Next flatten smooth back blades pitch change needed start wider blade narrow material available changing pitch See Fig 2 Remove material leading edge increase pitch trailing edge reduce pitch little material removal goes long way check pitch gauge go half-round wood rasp works best See Fig 3 cause twist blade sanding block tends round airfoil rather produce desired flat bottom 3 Once back smooth equal pitch both blades form airfoil Thin smooth top form leading edge sharp LE good Round somewhat Fig 1 shows typical airfoil 4 If span reduced first now Thin shape tips now 5 Next balance prop removing material front blade will preserve pitch carefully formed back side 6 Run prop engine April 1977 83 Kit No 804 DeHavilland Mu -I V . Mosquito 25% Wing S pan 16840 CMSI Approx Scale 7/16 ARTICLES WANTED Have design youd like have pub lished topic youd like write about tell editor about may worth money fiLttU&I*i PRODUCTS INC 535 DAVISYILLE ROAD OW GROVE PA 19090 658-3900 call CRAP TRAP* does exactlywhat think Crap Trap name purloined model builder Toledo Finally filter keep modern engines truly clean Call itan IMPURITIES FILTRATION SYSTEM want. call Crap Trap Newer sophisticated carburetors pumps very sensitive fine par ticles can get through filters Crap Trap Heres DOUBLE FILTRATIONIncludes two separate filters 100 mesh 007 openIng 120 mesh 004 opening Patent Applied MORE FILTER AREABoth filters cup-shaped greatly increase filter capacity COLOR CODEDFuel must go through larger silver mesh first filter out larger particles through smaller bronze mesh must WATCH IT WORKFilters encased see-through tubing CAN TAKE THE HEATThe extruded Teflon casing can handle temperatures up soo0 F 1 Between Tank 2 Between Fuel con3 Between Muffler Tank No need re move tubing muffler see tank Youve got try great new filter believe Watch action enjoy model its cleaner smoother-running engine note rpm its ballpark fly see works too low cut span put washout reduce pitch tip Use Fig 2 method get wash out outer span prop flutters give worst enemy start over funny noise rpm lower expected equals flutter will plane go slower stand chance having come apart running C Recomniendations Until someone comes up opti mum prop find major break through will trying following props 1 7-SN Rev-Up Thin TE little cleanup Cut span little necessary may best prop running muffler prop am currently using unmodified 2 7-SN Top Flite has little pitch 1 Clean up form good air foil bad airfoil out box rpm still low trim span slightly 3 7-6N Rev-Up has higher pitch 2 Thin clean up cut span may washout tips get rpm up RPM low out box 4 7-5 Rev-Up has blade area will allow bigger pitch changes anyone learns take advantage Ditto 7-5W Top Flite Dave Lane 4477 136th Hawthorne CA 90250 poductreviewproduetreeieWPVOdUCtrCViCWPrOdUCtrCViW Electric Twin Up now twin-engined electric powered RC scale model has seen kit form combination Model Flite England Polks International offer ing Britten/Norman Islander Powered two Model Flite Hummingbird motors pre wired installation spans 50 ins flying weight 3/a lbs nicad cassette pack 96V allows 8- 10-mm flights 30-mm recharge time Kit includes pre covered foam wings aileron cable stalled vacu-formed nacelles hardware pre cut prefab parts Props Cox6/3 spinners Prices Islander kit $6995 twin motor nicad pack $15995 charging monitor $3995 Polks Model-Craft Hobbies Inc 314 Fifth Ave New York NY 10001 producteiewproduetreviCwPtOdUetrCviWPrOdUCtrGVIeW F writing advertisers mention read about MA Goes/Hill Continued page 25 ventional airplane passes down wind upwind 228 210which would have record hap pened same flight So can done Lars Giertz possible improved tracks Houston smaller airplane what George flying good OPS Because lower total drag could did use 9 diameter propeller lets engine rev up bit 22000 get alls well Unfortu nately Lars aileron flutter prob lem early trials suffered dam age during launch No officials times recorded looked very fast must remember smaller air plane faster appears going Lars no throttle airplane arrangement will take really good pilot avoid having such smaller air plane disappear wild blue yonder out control Secing airplane biggest problems setting speed record Art Arros speed model looked good went over hill first flight due getting out controllable sight range Actually didnt have real chance because powered 40 too large Delta planform airplanes have lower 84 Model Aviation