This no-nonsense Slow Rat design capable winning performances years come state-of-the-art review made order play engines U John Kilsdonk author making needle valve adjustment before race Note battery strapped arm ACTUALLY Slow Rat Race new seems has around least six seven years am familiar called Sport Race Slow Race Novice Race other local terms designate being slower Rat Race model requirements new event revert back initially used early days Rat Race although specific limitations Rat Race models did resemble present Slow Rats During 1974-1975 AMA CLCB Controline Contest Board input RAC Racing Advisory Commit tee put together combination of local variations consistent set national rules specific rules re sulting can found pre sent AMA rule book Armed new rules set about develop racing package hoped would competitive preparation 1976 Nationals first step course refine model design basic requirements model would rugged streamlined rules allow easy build should possess basic flying characteristics re quired racing plane Bobcat model presented article result effort aircraft fully meets new rules both practice intent features no fancy frills basically both functional practical yet leaves little desired streamlining ship can built either two wing construction techniques shown plans first Bobcat 1975 King Orange Contest Jack sonville Florida built planked wing option used ST-35 PB performed excellently 100-mph range However engine did restart dependably hence did completed Bobcat can built sheeted wing covered Silkspan dope finished clear epoxy wing may Monokote-covered open frame pros cons 40 Model Aviation finish well race happy model flew no bad habits did everthing required good racer tracked well yet maneuvered excellently slowed down well pit stops could ask During winter 19761 set about work engines event June opportunity race model again contest Dayton Ohio During practice flight up leadout failed about 110 mph Instant disaster ruined excellent HP engine also totalled ship Nats month away really put design test barely enough time build another Bobcat would have perfect wouldnt have time much trimming decided try build two would have backup case another disaster further decided make open frame Monokote cov ered save finishing time about three weeks two Bobcats built between getting Goodyears Rat Racers order Nats test flew models Saturday before Nationals Again both flew identical first oneperfect OS engine other HP OS model per formed best both air speed pit stops So decided concentrate prac ticing model Nats now 1 /2 days away Well disaster struck again engine blew wrist pin just after finally everything working 3/16 OD TUBING FROM MECHANICAL FAST FILLFUEL BULB FIGURE NO1 SURGICAL TUBING SEAL 2 I/B HOLES 500 45 13/64 DRILL60 THRU 56001A300 250 130BALL .020 4096 HOLES T 90 SPRING 960 OI8NOM OODIA K \\ 020 PLATE FIT 10 SOLDER IN PLACE K MTL BRASS EXCEPT BALL AND SPRING ARE STEEL TTE 2T 7 7I V IRV 47 17iK~TI April1978 41 Some combinations power plants venturi evaluated development process Nose fuselage contours illustrate attention streamlining Engines used Bobcat turn B-B fiberglass prop pitched 7 in. slightly thinned 19200 20000 rpm way wanted night rebuilt engine spent Sunday afternoon getting broken going right again Monday Nats week Slow Rat thought ready now nerves becoming frazzled got off really well first 70-lap qualifying heat everything going fine until pit stop signaled pit pilot John Ballard brought Bobcat perfectly hit tool box other competitors inadvertently left landing area disaster put very large hole outboard wing rendered model unflyable judges conscientiously rescheduled heat Meanwhile Dick Lambert Paul Curtis helped rebuild wing Hot Stuff Devcon popsicle sticks Fast Cal turned out vain since heat finally re run missed needle setting fin ished ninth place qualifying Only top eight advanced finals After three unpredictable disasters definitely considered giving up Slow Rat However perseverence paid off Michigan Exchange Clubs Annual State Meet Contest finally got gether placed first time 614 three pit stops ran out fuel two laps go OS really running well clocked con sistently 148-150 secs 120 mph Inci dentally Dave Adamisin place second contest HP-powered Bobcat 620 time point very gratified almost solid year model engine development finally paid off OK lets get down building model First must decide Which wing construction will use Both shown plans After building Bobcats both ways must say slight advantages either fully sheeted wing takes longer finish about ounce heavier using Silkspan dope covered clear epoxy However marginally durable youre hurry dont like paint go open-frame construction Monokote Remember will still have paint fuselage stab rudder wing 42 Model Aviation front end showing installation modified HP engine Based upon results engine work described text author supplied sample 36 engines World Engines Midwest HPl same engine installation viewed bottom Shown en gine shut-oft mechanism tank Note placement landing gear Continuedonpage97 Top tail showing tne stitched figure 8 hinging eleva tor puller shut-off wire wire wrapped soldered pushrod Bottom view tail surfaces showing skids mounting tech nique consistency no detail can taken granted entries included Tom Lauries Douglas XB-42 Mixmaster Fernando Ramos Franco-Prussian Bloch powered troop glider Warren Shipps Uppercu-Burnelli UB 14 B Chuck Wests Westland Whirl wind Walt Mooneys Canadair George James Dornier Pfiel Bill Stromans Zeppelin Staaken Preferred power included twin geared motors contra-rotating XB-42 CO2 forthe BlochCox 020s Whirl wind electric Staaken Airspeed Ferry rubber Pfiel Burnelli Canadair Although en tries plagued minor problems failed make required 15-second qual ification flight such courage should ap plauded event won tri motored Airspeed biplane advantage being tested over year half preceeding contest Second went ol perfesser San Diego Walt Mooney Canadair rubber con tained nacelles gave just enough run rousing third Stromans Hercu lean effort Zep ROGd due pendulum stability con trols needed just tad bat tery department four Astro 02s seemed have enough potential fly eight-foot behemoth took off after about 50-foot run Bleaching Dr Martin nifty new way get light letters trim dark back ground comes George James George uses Dr Martins dye white tissue pur ple small brush Clo rox dye bleaches out unwanted areas Rapidograph pen handy small letters make edges trim large letters sharp Try next time want ultra-light job generally use Pres Bruning method sticking opaque letters color-doped tissue using spray rubber cement does add bit heavy some models Until next time thermals Send ideas pix etc pay used Bill Warner 423-C San Vicente Blvd. Santa Monica CA 90402 Bobcat/K ilsdonk continued page 42 ALL GRISH PROPELLERS ARE ENGINEERED TO TRUE 1-IELICAL PITCH AND AIRFOIL FOR EFFICIENCY 2 Blade Tractor 5-3each 5-45/a-35Y2-4304 6-36-4354 747-67-8504 8-48-68-8654 9-4g-6g-7 9-810-410-6854 11-411-611-8$1 12-412-512-6$150 2 Blade Pusher 5Y2-4 6-36-4354 8-6854 9-610-6$1 3 Blade Tractor 6-36-36-4 504 3 Blade Pusher 6-3504 Made polyester boll Color signed no-nonsense airfoil sheeted meets one-inch wing thickness rule need two rib except No 1 Glue ribs 1/4 X 3/s bottom spar leading edge Any new cyanoacrylates Hot-Stuff Zap etc recommended entire wing construction building openframe construction glue trailing edge sheeting followed LE center section rib cap strips fully sheeted wing completely sheeted bottom side bellcrank installed along wing tip skid mounts blind nuts USE TO PROPEL AIR CREATE THRUST AND PROPELLED BY AIR Metallic Aluminum Color 7-67-8$1 8-68-8$125 9-6 10-610-4$150 Pusher 10-6$150 entire top sheeted Dont forget stall pushrods before installing center top section sheeting wing tips can made either 1 balsa double thickness scrap a left over fuselage plank tips carved hollowed out shown Glue Titebond epoxy No wing tip weight required Finish sand sheeted surfaces 150 220 grit garnet paper wing done fuselage stab rudder very straightforward use tank re cessed fuselage shown install outboard plywood doubler first cut tips rib templates plans de product review product review product review cock$t fl coaming__ Cockpit Coaming extruded flexible black vinyl material pre-shaped fit around corner two sizes 3/32and 3/16 dia Price 2 feet size $195 Strut Fairing extruded rigid vinyl two sizes 3/32 1/8 lD packaged two 23 lengths Price size $225 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review THIS FORM ND ATTACH MAILING XI5S~J ABEL FROM RECENT LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept Model Aviation 815 Fifteenth St. NW Washington DC 20005 Check appropriate boxenclose payment C NEW SUBSCRIPTION C CHANGE OF ADDRESS Non-AMA subscription rates $1200 12 months Canada United States possession elsewhere $1400 NAME ADDRESS CITY/STATE ____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW. WASHINGTON DC 20005 April1978 97 GRISH AIRCRAFT TYPE PROPELLERS Made hardwood fully carved true helical pitch airfoil ready sanding ALL SIZES IN18$700 8 & 10 PITCH20800 221000 241300 AT YOUR DEALER RIGHT HAND ROTATION 318 BORE T DISCRETION OF HE PURCHASER 3 E PROPELLERS AT YOUR OALER Os G RUSH ST JOHN INDIANA 46373 CONTROL LINE KITS WEVE GOT EM STARTING T $595 Si Ringmaster S2 FS1 Mustang S3 Yak9 S5 Ringmaster Jr SS Super Ringmaster S12 Flying FenI S13 Baby Ringmaster S15 Rutty Sil P38 Lightning SiS Ringmaster Imper S19 Spitfire S22 Ringmaster Spurts S27 Skylark S28 Sky Shark S29 Ring Jr Flash S30 Beginners Ring 1595 1695 1595 1095 1995 1895 195 2995 1695 2895 3595 1995 3495 1995 1295 595 S31Beginners Mustang595 S32Beg Ring Bipe695 S33Winder1395 S34Beginners Spitfire595 S35Beginners Thunder Jet595 S36Beginners Piper Cub595 S37Beginners tindecker595 S38Beginners Shuestring595 S39Beginners Thunderbult595 S40Beginners Cherukee595 S41Beginners Fnkker Dl695 S42Beginners Hellcat595 S43Beginners FnckeWnlf595 S44Beginners Zern595 545Beginners Messerschmitt595 out slot tank install inboard doubler landing gear use blind nuts engine mount fuel shut-off mount coat-hanger wire rubberbands fuel tank holddown also prefer hardwood tail skid mount blind nuts shown plans After completed fuselage glued wing using either Titebond epoxy making sure fuselage exact center wing perpendicular LE cheek cowl rudder stabilizer glued place again either Tite bond epoxy Make sure tail surfaces parallel square re quired use 3/4 oz fiberglass cloth around cheek cowl K&B surfacing resin surfaces painted followed coat two Hobbypoxy color open areas covered Monokote Solarfilm fully sheeted wing uses same techniques however heavier old-fashioned method 00 Silkspan clear dope talcum powder followed colored dope coat clear epoxy fuel shut off shown similar used Goodyears can fabricated easily /8 aluminum plate lazy hurry commercial W-K Kustom Kraft can substitu ted plans show pusher type shut off what prefer because no solder joints however puller ClMonucunpe C3Mr Mulligan C4The Wacn CsSE5 CSiekker 07 C9Corsair ClONinupert 28 CliGrumman Guardian C12Stearman PT17 C13Great Lakes 1995 1995 2195 2295 2195 2395 2295 2895 2295 2495 STERLING MODELS G ST PHILA PA 19134 no dealer availabte dIrect orders accepted addllio,al charge tar handing shipping tune mininun US. 5125 minimum ostside USl I] Catalog entire line airplane control line mnodei hits it/C scum Trainer kits boat model kits accessories etc Sue enclosed C Secrets Model Airplane Building including design construction cayenne tinishing flying adlusting control systems etc 25c enclosed 0 Secrets Control Line Carrier Flyinn Including preflight soloing stunting Carrier flies regulations Carrier hymn hints control tine inatalfatton instructions 25C enclosed NO checks Only US meney orders currency accepted Name ____________________________ . AddressCity e Zip type may used used two models built quickly Nats Whichever method prefer should actuated full down elevator Bobcat designed around 3-oz old Veco T-21C tank now manufactured Fox tank modi fied either Dons fast-fill use Uniflow vent arrangement like will have fabricate mechanical fast-fill brass bar stock shown Fig No mechanical type provides positive seal irrespective tank pres sure uniflow tank has described times especially Stunt columns will go However far superior conventional assemblies engine consistency though out flight problems encountered event restart pit stops due fuel starvation engine because pressurization allowed prime either exhaust intake would work proved inconsistent time consuming overcome develop ed fueling system shown sliding piece surgical tubing up over fuel fill pipe fuel bulb act seal bulb pushed down mechanical fast-fill air escapes either through single tank vent fuel line tank full fuel therefore escapes through same lines Since fuel being pushed through 5/32 ID pipe bulb cannot vented through 3/32 ID verflow line tank vent hence some must go through fuel supply line engine little practice will de velop touch know hard squeeze bulb during period de livery proper prime engine probably sounds complicated really isnt does work dependably complicated part Slow Rat project engine tried existing 35s 36s course flying observing midwestern Sport Race events over past years Also experiences both Rat Race Goodyear obvi ous needed 36 displacement en gine incorporated ringed piston restarts ball bearings durabil ity Schnuerle porting maximum power Obviously nothing commer cially available time develop something own first approach use basic Supertigre G-21-40 RRV engine used much success 9-10 years ago Rat Race wasnt Schnuerle ported did have other two requireproduct review product review product review New Cannon 1978 five different model lines offered 2 7 channels ranging worlds smallest systems Custom-built 7-Channel test flown covered 1-year warranty models employ new xmitter circuit providing maxi mum legal output 750 milliwatts 72 MHz Newest Mini-Sport System 2-channel dry $11995 5channel nicads $259953-axis single stick 4 5 chan nels available extra cost Standardized plastic xmitter case allows factory conversion Mini-Sport models up 5 channels Any xmitter may converted upwards 4 5 channels 2-stick 3-axis single stick Con version cost $10 retail purchase price difference between original upgrad ed systems Two-axis open-gimbal sticks xmitters systems offer selection servos Flite Packs Full-power Flite Packs use 125 oz servos 4 lbs thrust 500 ma receiver nicads Miniature Flite Packs use 75 oz ser vos 3 lbs thrust choice battery packs 100 250 ma Either pack available separate ly systems available 27 293540 53 72 MHz bands $15 extra 29 3540 53 including new Canadian 72 frequen cies Brochure 25c stamps OK $100 US foreign Cannon RIC Systems1340026 Saticoy St N Hollywood CA 91605 product review product review product review 98 Model Aviation ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em all
Edition: Model Aviation - 1978/04
Page Numbers: 40, 41, 42, 97, 98, 99
This no-nonsense Slow Rat design capable winning performances years come state-of-the-art review made order play engines U John Kilsdonk author making needle valve adjustment before race Note battery strapped arm ACTUALLY Slow Rat Race new seems has around least six seven years am familiar called Sport Race Slow Race Novice Race other local terms designate being slower Rat Race model requirements new event revert back initially used early days Rat Race although specific limitations Rat Race models did resemble present Slow Rats During 1974-1975 AMA CLCB Controline Contest Board input RAC Racing Advisory Commit tee put together combination of local variations consistent set national rules specific rules re sulting can found pre sent AMA rule book Armed new rules set about develop racing package hoped would competitive preparation 1976 Nationals first step course refine model design basic requirements model would rugged streamlined rules allow easy build should possess basic flying characteristics re quired racing plane Bobcat model presented article result effort aircraft fully meets new rules both practice intent features no fancy frills basically both functional practical yet leaves little desired streamlining ship can built either two wing construction techniques shown plans first Bobcat 1975 King Orange Contest Jack sonville Florida built planked wing option used ST-35 PB performed excellently 100-mph range However engine did restart dependably hence did completed Bobcat can built sheeted wing covered Silkspan dope finished clear epoxy wing may Monokote-covered open frame pros cons 40 Model Aviation finish well race happy model flew no bad habits did everthing required good racer tracked well yet maneuvered excellently slowed down well pit stops could ask During winter 19761 set about work engines event June opportunity race model again contest Dayton Ohio During practice flight up leadout failed about 110 mph Instant disaster ruined excellent HP engine also totalled ship Nats month away really put design test barely enough time build another Bobcat would have perfect wouldnt have time much trimming decided try build two would have backup case another disaster further decided make open frame Monokote cov ered save finishing time about three weeks two Bobcats built between getting Goodyears Rat Racers order Nats test flew models Saturday before Nationals Again both flew identical first oneperfect OS engine other HP OS model per formed best both air speed pit stops So decided concentrate prac ticing model Nats now 1 /2 days away Well disaster struck again engine blew wrist pin just after finally everything working 3/16 OD TUBING FROM MECHANICAL FAST FILLFUEL BULB FIGURE NO1 SURGICAL TUBING SEAL 2 I/B HOLES 500 45 13/64 DRILL60 THRU 56001A300 250 130BALL .020 4096 HOLES T 90 SPRING 960 OI8NOM OODIA K \\ 020 PLATE FIT 10 SOLDER IN PLACE K MTL BRASS EXCEPT BALL AND SPRING ARE STEEL TTE 2T 7 7I V IRV 47 17iK~TI April1978 41 Some combinations power plants venturi evaluated development process Nose fuselage contours illustrate attention streamlining Engines used Bobcat turn B-B fiberglass prop pitched 7 in. slightly thinned 19200 20000 rpm way wanted night rebuilt engine spent Sunday afternoon getting broken going right again Monday Nats week Slow Rat thought ready now nerves becoming frazzled got off really well first 70-lap qualifying heat everything going fine until pit stop signaled pit pilot John Ballard brought Bobcat perfectly hit tool box other competitors inadvertently left landing area disaster put very large hole outboard wing rendered model unflyable judges conscientiously rescheduled heat Meanwhile Dick Lambert Paul Curtis helped rebuild wing Hot Stuff Devcon popsicle sticks Fast Cal turned out vain since heat finally re run missed needle setting fin ished ninth place qualifying Only top eight advanced finals After three unpredictable disasters definitely considered giving up Slow Rat However perseverence paid off Michigan Exchange Clubs Annual State Meet Contest finally got gether placed first time 614 three pit stops ran out fuel two laps go OS really running well clocked con sistently 148-150 secs 120 mph Inci dentally Dave Adamisin place second contest HP-powered Bobcat 620 time point very gratified almost solid year model engine development finally paid off OK lets get down building model First must decide Which wing construction will use Both shown plans After building Bobcats both ways must say slight advantages either fully sheeted wing takes longer finish about ounce heavier using Silkspan dope covered clear epoxy However marginally durable youre hurry dont like paint go open-frame construction Monokote Remember will still have paint fuselage stab rudder wing 42 Model Aviation front end showing installation modified HP engine Based upon results engine work described text author supplied sample 36 engines World Engines Midwest HPl same engine installation viewed bottom Shown en gine shut-oft mechanism tank Note placement landing gear Continuedonpage97 Top tail showing tne stitched figure 8 hinging eleva tor puller shut-off wire wire wrapped soldered pushrod Bottom view tail surfaces showing skids mounting tech nique consistency no detail can taken granted entries included Tom Lauries Douglas XB-42 Mixmaster Fernando Ramos Franco-Prussian Bloch powered troop glider Warren Shipps Uppercu-Burnelli UB 14 B Chuck Wests Westland Whirl wind Walt Mooneys Canadair George James Dornier Pfiel Bill Stromans Zeppelin Staaken Preferred power included twin geared motors contra-rotating XB-42 CO2 forthe BlochCox 020s Whirl wind electric Staaken Airspeed Ferry rubber Pfiel Burnelli Canadair Although en tries plagued minor problems failed make required 15-second qual ification flight such courage should ap plauded event won tri motored Airspeed biplane advantage being tested over year half preceeding contest Second went ol perfesser San Diego Walt Mooney Canadair rubber con tained nacelles gave just enough run rousing third Stromans Hercu lean effort Zep ROGd due pendulum stability con trols needed just tad bat tery department four Astro 02s seemed have enough potential fly eight-foot behemoth took off after about 50-foot run Bleaching Dr Martin nifty new way get light letters trim dark back ground comes George James George uses Dr Martins dye white tissue pur ple small brush Clo rox dye bleaches out unwanted areas Rapidograph pen handy small letters make edges trim large letters sharp Try next time want ultra-light job generally use Pres Bruning method sticking opaque letters color-doped tissue using spray rubber cement does add bit heavy some models Until next time thermals Send ideas pix etc pay used Bill Warner 423-C San Vicente Blvd. Santa Monica CA 90402 Bobcat/K ilsdonk continued page 42 ALL GRISH PROPELLERS ARE ENGINEERED TO TRUE 1-IELICAL PITCH AND AIRFOIL FOR EFFICIENCY 2 Blade Tractor 5-3each 5-45/a-35Y2-4304 6-36-4354 747-67-8504 8-48-68-8654 9-4g-6g-7 9-810-410-6854 11-411-611-8$1 12-412-512-6$150 2 Blade Pusher 5Y2-4 6-36-4354 8-6854 9-610-6$1 3 Blade Tractor 6-36-36-4 504 3 Blade Pusher 6-3504 Made polyester boll Color signed no-nonsense airfoil sheeted meets one-inch wing thickness rule need two rib except No 1 Glue ribs 1/4 X 3/s bottom spar leading edge Any new cyanoacrylates Hot-Stuff Zap etc recommended entire wing construction building openframe construction glue trailing edge sheeting followed LE center section rib cap strips fully sheeted wing completely sheeted bottom side bellcrank installed along wing tip skid mounts blind nuts USE TO PROPEL AIR CREATE THRUST AND PROPELLED BY AIR Metallic Aluminum Color 7-67-8$1 8-68-8$125 9-6 10-610-4$150 Pusher 10-6$150 entire top sheeted Dont forget stall pushrods before installing center top section sheeting wing tips can made either 1 balsa double thickness scrap a left over fuselage plank tips carved hollowed out shown Glue Titebond epoxy No wing tip weight required Finish sand sheeted surfaces 150 220 grit garnet paper wing done fuselage stab rudder very straightforward use tank re cessed fuselage shown install outboard plywood doubler first cut tips rib templates plans de product review product review product review cock$t fl coaming__ Cockpit Coaming extruded flexible black vinyl material pre-shaped fit around corner two sizes 3/32and 3/16 dia Price 2 feet size $195 Strut Fairing extruded rigid vinyl two sizes 3/32 1/8 lD packaged two 23 lengths Price size $225 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review THIS FORM ND ATTACH MAILING XI5S~J ABEL FROM RECENT LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept Model Aviation 815 Fifteenth St. NW Washington DC 20005 Check appropriate boxenclose payment C NEW SUBSCRIPTION C CHANGE OF ADDRESS Non-AMA subscription rates $1200 12 months Canada United States possession elsewhere $1400 NAME ADDRESS CITY/STATE ____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW. WASHINGTON DC 20005 April1978 97 GRISH AIRCRAFT TYPE PROPELLERS Made hardwood fully carved true helical pitch airfoil ready sanding ALL SIZES IN18$700 8 & 10 PITCH20800 221000 241300 AT YOUR DEALER RIGHT HAND ROTATION 318 BORE T DISCRETION OF HE PURCHASER 3 E PROPELLERS AT YOUR OALER Os G RUSH ST JOHN INDIANA 46373 CONTROL LINE KITS WEVE GOT EM STARTING T $595 Si Ringmaster S2 FS1 Mustang S3 Yak9 S5 Ringmaster Jr SS Super Ringmaster S12 Flying FenI S13 Baby Ringmaster S15 Rutty Sil P38 Lightning SiS Ringmaster Imper S19 Spitfire S22 Ringmaster Spurts S27 Skylark S28 Sky Shark S29 Ring Jr Flash S30 Beginners Ring 1595 1695 1595 1095 1995 1895 195 2995 1695 2895 3595 1995 3495 1995 1295 595 S31Beginners Mustang595 S32Beg Ring Bipe695 S33Winder1395 S34Beginners Spitfire595 S35Beginners Thunder Jet595 S36Beginners Piper Cub595 S37Beginners tindecker595 S38Beginners Shuestring595 S39Beginners Thunderbult595 S40Beginners Cherukee595 S41Beginners Fnkker Dl695 S42Beginners Hellcat595 S43Beginners FnckeWnlf595 S44Beginners Zern595 545Beginners Messerschmitt595 out slot tank install inboard doubler landing gear use blind nuts engine mount fuel shut-off mount coat-hanger wire rubberbands fuel tank holddown also prefer hardwood tail skid mount blind nuts shown plans After completed fuselage glued wing using either Titebond epoxy making sure fuselage exact center wing perpendicular LE cheek cowl rudder stabilizer glued place again either Tite bond epoxy Make sure tail surfaces parallel square re quired use 3/4 oz fiberglass cloth around cheek cowl K&B surfacing resin surfaces painted followed coat two Hobbypoxy color open areas covered Monokote Solarfilm fully sheeted wing uses same techniques however heavier old-fashioned method 00 Silkspan clear dope talcum powder followed colored dope coat clear epoxy fuel shut off shown similar used Goodyears can fabricated easily /8 aluminum plate lazy hurry commercial W-K Kustom Kraft can substitu ted plans show pusher type shut off what prefer because no solder joints however puller ClMonucunpe C3Mr Mulligan C4The Wacn CsSE5 CSiekker 07 C9Corsair ClONinupert 28 CliGrumman Guardian C12Stearman PT17 C13Great Lakes 1995 1995 2195 2295 2195 2395 2295 2895 2295 2495 STERLING MODELS G ST PHILA PA 19134 no dealer availabte dIrect orders accepted addllio,al charge tar handing shipping tune mininun US. 5125 minimum ostside USl I] Catalog entire line airplane control line mnodei hits it/C scum Trainer kits boat model kits accessories etc Sue enclosed C Secrets Model Airplane Building including design construction cayenne tinishing flying adlusting control systems etc 25c enclosed 0 Secrets Control Line Carrier Flyinn Including preflight soloing stunting Carrier flies regulations Carrier hymn hints control tine inatalfatton instructions 25C enclosed NO checks Only US meney orders currency accepted Name ____________________________ . AddressCity e Zip type may used used two models built quickly Nats Whichever method prefer should actuated full down elevator Bobcat designed around 3-oz old Veco T-21C tank now manufactured Fox tank modi fied either Dons fast-fill use Uniflow vent arrangement like will have fabricate mechanical fast-fill brass bar stock shown Fig No mechanical type provides positive seal irrespective tank pres sure uniflow tank has described times especially Stunt columns will go However far superior conventional assemblies engine consistency though out flight problems encountered event restart pit stops due fuel starvation engine because pressurization allowed prime either exhaust intake would work proved inconsistent time consuming overcome develop ed fueling system shown sliding piece surgical tubing up over fuel fill pipe fuel bulb act seal bulb pushed down mechanical fast-fill air escapes either through single tank vent fuel line tank full fuel therefore escapes through same lines Since fuel being pushed through 5/32 ID pipe bulb cannot vented through 3/32 ID verflow line tank vent hence some must go through fuel supply line engine little practice will de velop touch know hard squeeze bulb during period de livery proper prime engine probably sounds complicated really isnt does work dependably complicated part Slow Rat project engine tried existing 35s 36s course flying observing midwestern Sport Race events over past years Also experiences both Rat Race Goodyear obvi ous needed 36 displacement en gine incorporated ringed piston restarts ball bearings durabil ity Schnuerle porting maximum power Obviously nothing commer cially available time develop something own first approach use basic Supertigre G-21-40 RRV engine used much success 9-10 years ago Rat Race wasnt Schnuerle ported did have other two requireproduct review product review product review New Cannon 1978 five different model lines offered 2 7 channels ranging worlds smallest systems Custom-built 7-Channel test flown covered 1-year warranty models employ new xmitter circuit providing maxi mum legal output 750 milliwatts 72 MHz Newest Mini-Sport System 2-channel dry $11995 5channel nicads $259953-axis single stick 4 5 chan nels available extra cost Standardized plastic xmitter case allows factory conversion Mini-Sport models up 5 channels Any xmitter may converted upwards 4 5 channels 2-stick 3-axis single stick Con version cost $10 retail purchase price difference between original upgrad ed systems Two-axis open-gimbal sticks xmitters systems offer selection servos Flite Packs Full-power Flite Packs use 125 oz servos 4 lbs thrust 500 ma receiver nicads Miniature Flite Packs use 75 oz ser vos 3 lbs thrust choice battery packs 100 250 ma Either pack available separate ly systems available 27 293540 53 72 MHz bands $15 extra 29 3540 53 including new Canadian 72 frequen cies Brochure 25c stamps OK $100 US foreign Cannon RIC Systems1340026 Saticoy St N Hollywood CA 91605 product review product review product review 98 Model Aviation ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em all
Edition: Model Aviation - 1978/04
Page Numbers: 40, 41, 42, 97, 98, 99
This no-nonsense Slow Rat design capable winning performances years come state-of-the-art review made order play engines U John Kilsdonk author making needle valve adjustment before race Note battery strapped arm ACTUALLY Slow Rat Race new seems has around least six seven years am familiar called Sport Race Slow Race Novice Race other local terms designate being slower Rat Race model requirements new event revert back initially used early days Rat Race although specific limitations Rat Race models did resemble present Slow Rats During 1974-1975 AMA CLCB Controline Contest Board input RAC Racing Advisory Commit tee put together combination of local variations consistent set national rules specific rules re sulting can found pre sent AMA rule book Armed new rules set about develop racing package hoped would competitive preparation 1976 Nationals first step course refine model design basic requirements model would rugged streamlined rules allow easy build should possess basic flying characteristics re quired racing plane Bobcat model presented article result effort aircraft fully meets new rules both practice intent features no fancy frills basically both functional practical yet leaves little desired streamlining ship can built either two wing construction techniques shown plans first Bobcat 1975 King Orange Contest Jack sonville Florida built planked wing option used ST-35 PB performed excellently 100-mph range However engine did restart dependably hence did completed Bobcat can built sheeted wing covered Silkspan dope finished clear epoxy wing may Monokote-covered open frame pros cons 40 Model Aviation finish well race happy model flew no bad habits did everthing required good racer tracked well yet maneuvered excellently slowed down well pit stops could ask During winter 19761 set about work engines event June opportunity race model again contest Dayton Ohio During practice flight up leadout failed about 110 mph Instant disaster ruined excellent HP engine also totalled ship Nats month away really put design test barely enough time build another Bobcat would have perfect wouldnt have time much trimming decided try build two would have backup case another disaster further decided make open frame Monokote cov ered save finishing time about three weeks two Bobcats built between getting Goodyears Rat Racers order Nats test flew models Saturday before Nationals Again both flew identical first oneperfect OS engine other HP OS model per formed best both air speed pit stops So decided concentrate prac ticing model Nats now 1 /2 days away Well disaster struck again engine blew wrist pin just after finally everything working 3/16 OD TUBING FROM MECHANICAL FAST FILLFUEL BULB FIGURE NO1 SURGICAL TUBING SEAL 2 I/B HOLES 500 45 13/64 DRILL60 THRU 56001A300 250 130BALL .020 4096 HOLES T 90 SPRING 960 OI8NOM OODIA K \\ 020 PLATE FIT 10 SOLDER IN PLACE K MTL BRASS EXCEPT BALL AND SPRING ARE STEEL TTE 2T 7 7I V IRV 47 17iK~TI April1978 41 Some combinations power plants venturi evaluated development process Nose fuselage contours illustrate attention streamlining Engines used Bobcat turn B-B fiberglass prop pitched 7 in. slightly thinned 19200 20000 rpm way wanted night rebuilt engine spent Sunday afternoon getting broken going right again Monday Nats week Slow Rat thought ready now nerves becoming frazzled got off really well first 70-lap qualifying heat everything going fine until pit stop signaled pit pilot John Ballard brought Bobcat perfectly hit tool box other competitors inadvertently left landing area disaster put very large hole outboard wing rendered model unflyable judges conscientiously rescheduled heat Meanwhile Dick Lambert Paul Curtis helped rebuild wing Hot Stuff Devcon popsicle sticks Fast Cal turned out vain since heat finally re run missed needle setting fin ished ninth place qualifying Only top eight advanced finals After three unpredictable disasters definitely considered giving up Slow Rat However perseverence paid off Michigan Exchange Clubs Annual State Meet Contest finally got gether placed first time 614 three pit stops ran out fuel two laps go OS really running well clocked con sistently 148-150 secs 120 mph Inci dentally Dave Adamisin place second contest HP-powered Bobcat 620 time point very gratified almost solid year model engine development finally paid off OK lets get down building model First must decide Which wing construction will use Both shown plans After building Bobcats both ways must say slight advantages either fully sheeted wing takes longer finish about ounce heavier using Silkspan dope covered clear epoxy However marginally durable youre hurry dont like paint go open-frame construction Monokote Remember will still have paint fuselage stab rudder wing 42 Model Aviation front end showing installation modified HP engine Based upon results engine work described text author supplied sample 36 engines World Engines Midwest HPl same engine installation viewed bottom Shown en gine shut-oft mechanism tank Note placement landing gear Continuedonpage97 Top tail showing tne stitched figure 8 hinging eleva tor puller shut-off wire wire wrapped soldered pushrod Bottom view tail surfaces showing skids mounting tech nique consistency no detail can taken granted entries included Tom Lauries Douglas XB-42 Mixmaster Fernando Ramos Franco-Prussian Bloch powered troop glider Warren Shipps Uppercu-Burnelli UB 14 B Chuck Wests Westland Whirl wind Walt Mooneys Canadair George James Dornier Pfiel Bill Stromans Zeppelin Staaken Preferred power included twin geared motors contra-rotating XB-42 CO2 forthe BlochCox 020s Whirl wind electric Staaken Airspeed Ferry rubber Pfiel Burnelli Canadair Although en tries plagued minor problems failed make required 15-second qual ification flight such courage should ap plauded event won tri motored Airspeed biplane advantage being tested over year half preceeding contest Second went ol perfesser San Diego Walt Mooney Canadair rubber con tained nacelles gave just enough run rousing third Stromans Hercu lean effort Zep ROGd due pendulum stability con trols needed just tad bat tery department four Astro 02s seemed have enough potential fly eight-foot behemoth took off after about 50-foot run Bleaching Dr Martin nifty new way get light letters trim dark back ground comes George James George uses Dr Martins dye white tissue pur ple small brush Clo rox dye bleaches out unwanted areas Rapidograph pen handy small letters make edges trim large letters sharp Try next time want ultra-light job generally use Pres Bruning method sticking opaque letters color-doped tissue using spray rubber cement does add bit heavy some models Until next time thermals Send ideas pix etc pay used Bill Warner 423-C San Vicente Blvd. Santa Monica CA 90402 Bobcat/K ilsdonk continued page 42 ALL GRISH PROPELLERS ARE ENGINEERED TO TRUE 1-IELICAL PITCH AND AIRFOIL FOR EFFICIENCY 2 Blade Tractor 5-3each 5-45/a-35Y2-4304 6-36-4354 747-67-8504 8-48-68-8654 9-4g-6g-7 9-810-410-6854 11-411-611-8$1 12-412-512-6$150 2 Blade Pusher 5Y2-4 6-36-4354 8-6854 9-610-6$1 3 Blade Tractor 6-36-36-4 504 3 Blade Pusher 6-3504 Made polyester boll Color signed no-nonsense airfoil sheeted meets one-inch wing thickness rule need two rib except No 1 Glue ribs 1/4 X 3/s bottom spar leading edge Any new cyanoacrylates Hot-Stuff Zap etc recommended entire wing construction building openframe construction glue trailing edge sheeting followed LE center section rib cap strips fully sheeted wing completely sheeted bottom side bellcrank installed along wing tip skid mounts blind nuts USE TO PROPEL AIR CREATE THRUST AND PROPELLED BY AIR Metallic Aluminum Color 7-67-8$1 8-68-8$125 9-6 10-610-4$150 Pusher 10-6$150 entire top sheeted Dont forget stall pushrods before installing center top section sheeting wing tips can made either 1 balsa double thickness scrap a left over fuselage plank tips carved hollowed out shown Glue Titebond epoxy No wing tip weight required Finish sand sheeted surfaces 150 220 grit garnet paper wing done fuselage stab rudder very straightforward use tank re cessed fuselage shown install outboard plywood doubler first cut tips rib templates plans de product review product review product review cock$t fl coaming__ Cockpit Coaming extruded flexible black vinyl material pre-shaped fit around corner two sizes 3/32and 3/16 dia Price 2 feet size $195 Strut Fairing extruded rigid vinyl two sizes 3/32 1/8 lD packaged two 23 lengths Price size $225 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review THIS FORM ND ATTACH MAILING XI5S~J ABEL FROM RECENT LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept Model Aviation 815 Fifteenth St. NW Washington DC 20005 Check appropriate boxenclose payment C NEW SUBSCRIPTION C CHANGE OF ADDRESS Non-AMA subscription rates $1200 12 months Canada United States possession elsewhere $1400 NAME ADDRESS CITY/STATE ____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW. WASHINGTON DC 20005 April1978 97 GRISH AIRCRAFT TYPE PROPELLERS Made hardwood fully carved true helical pitch airfoil ready sanding ALL SIZES IN18$700 8 & 10 PITCH20800 221000 241300 AT YOUR DEALER RIGHT HAND ROTATION 318 BORE T DISCRETION OF HE PURCHASER 3 E PROPELLERS AT YOUR OALER Os G RUSH ST JOHN INDIANA 46373 CONTROL LINE KITS WEVE GOT EM STARTING T $595 Si Ringmaster S2 FS1 Mustang S3 Yak9 S5 Ringmaster Jr SS Super Ringmaster S12 Flying FenI S13 Baby Ringmaster S15 Rutty Sil P38 Lightning SiS Ringmaster Imper S19 Spitfire S22 Ringmaster Spurts S27 Skylark S28 Sky Shark S29 Ring Jr Flash S30 Beginners Ring 1595 1695 1595 1095 1995 1895 195 2995 1695 2895 3595 1995 3495 1995 1295 595 S31Beginners Mustang595 S32Beg Ring Bipe695 S33Winder1395 S34Beginners Spitfire595 S35Beginners Thunder Jet595 S36Beginners Piper Cub595 S37Beginners tindecker595 S38Beginners Shuestring595 S39Beginners Thunderbult595 S40Beginners Cherukee595 S41Beginners Fnkker Dl695 S42Beginners Hellcat595 S43Beginners FnckeWnlf595 S44Beginners Zern595 545Beginners Messerschmitt595 out slot tank install inboard doubler landing gear use blind nuts engine mount fuel shut-off mount coat-hanger wire rubberbands fuel tank holddown also prefer hardwood tail skid mount blind nuts shown plans After completed fuselage glued wing using either Titebond epoxy making sure fuselage exact center wing perpendicular LE cheek cowl rudder stabilizer glued place again either Tite bond epoxy Make sure tail surfaces parallel square re quired use 3/4 oz fiberglass cloth around cheek cowl K&B surfacing resin surfaces painted followed coat two Hobbypoxy color open areas covered Monokote Solarfilm fully sheeted wing uses same techniques however heavier old-fashioned method 00 Silkspan clear dope talcum powder followed colored dope coat clear epoxy fuel shut off shown similar used Goodyears can fabricated easily /8 aluminum plate lazy hurry commercial W-K Kustom Kraft can substitu ted plans show pusher type shut off what prefer because no solder joints however puller ClMonucunpe C3Mr Mulligan C4The Wacn CsSE5 CSiekker 07 C9Corsair ClONinupert 28 CliGrumman Guardian C12Stearman PT17 C13Great Lakes 1995 1995 2195 2295 2195 2395 2295 2895 2295 2495 STERLING MODELS G ST PHILA PA 19134 no dealer availabte dIrect orders accepted addllio,al charge tar handing shipping tune mininun US. 5125 minimum ostside USl I] Catalog entire line airplane control line mnodei hits it/C scum Trainer kits boat model kits accessories etc Sue enclosed C Secrets Model Airplane Building including design construction cayenne tinishing flying adlusting control systems etc 25c enclosed 0 Secrets Control Line Carrier Flyinn Including preflight soloing stunting Carrier flies regulations Carrier hymn hints control tine inatalfatton instructions 25C enclosed NO checks Only US meney orders currency accepted Name ____________________________ . AddressCity e Zip type may used used two models built quickly Nats Whichever method prefer should actuated full down elevator Bobcat designed around 3-oz old Veco T-21C tank now manufactured Fox tank modi fied either Dons fast-fill use Uniflow vent arrangement like will have fabricate mechanical fast-fill brass bar stock shown Fig No mechanical type provides positive seal irrespective tank pres sure uniflow tank has described times especially Stunt columns will go However far superior conventional assemblies engine consistency though out flight problems encountered event restart pit stops due fuel starvation engine because pressurization allowed prime either exhaust intake would work proved inconsistent time consuming overcome develop ed fueling system shown sliding piece surgical tubing up over fuel fill pipe fuel bulb act seal bulb pushed down mechanical fast-fill air escapes either through single tank vent fuel line tank full fuel therefore escapes through same lines Since fuel being pushed through 5/32 ID pipe bulb cannot vented through 3/32 ID verflow line tank vent hence some must go through fuel supply line engine little practice will de velop touch know hard squeeze bulb during period de livery proper prime engine probably sounds complicated really isnt does work dependably complicated part Slow Rat project engine tried existing 35s 36s course flying observing midwestern Sport Race events over past years Also experiences both Rat Race Goodyear obvi ous needed 36 displacement en gine incorporated ringed piston restarts ball bearings durabil ity Schnuerle porting maximum power Obviously nothing commer cially available time develop something own first approach use basic Supertigre G-21-40 RRV engine used much success 9-10 years ago Rat Race wasnt Schnuerle ported did have other two requireproduct review product review product review New Cannon 1978 five different model lines offered 2 7 channels ranging worlds smallest systems Custom-built 7-Channel test flown covered 1-year warranty models employ new xmitter circuit providing maxi mum legal output 750 milliwatts 72 MHz Newest Mini-Sport System 2-channel dry $11995 5channel nicads $259953-axis single stick 4 5 chan nels available extra cost Standardized plastic xmitter case allows factory conversion Mini-Sport models up 5 channels Any xmitter may converted upwards 4 5 channels 2-stick 3-axis single stick Con version cost $10 retail purchase price difference between original upgrad ed systems Two-axis open-gimbal sticks xmitters systems offer selection servos Flite Packs Full-power Flite Packs use 125 oz servos 4 lbs thrust 500 ma receiver nicads Miniature Flite Packs use 75 oz ser vos 3 lbs thrust choice battery packs 100 250 ma Either pack available separate ly systems available 27 293540 53 72 MHz bands $15 extra 29 3540 53 including new Canadian 72 frequen cies Brochure 25c stamps OK $100 US foreign Cannon RIC Systems1340026 Saticoy St N Hollywood CA 91605 product review product review product review 98 Model Aviation ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em all
Edition: Model Aviation - 1978/04
Page Numbers: 40, 41, 42, 97, 98, 99
This no-nonsense Slow Rat design capable winning performances years come state-of-the-art review made order play engines U John Kilsdonk author making needle valve adjustment before race Note battery strapped arm ACTUALLY Slow Rat Race new seems has around least six seven years am familiar called Sport Race Slow Race Novice Race other local terms designate being slower Rat Race model requirements new event revert back initially used early days Rat Race although specific limitations Rat Race models did resemble present Slow Rats During 1974-1975 AMA CLCB Controline Contest Board input RAC Racing Advisory Commit tee put together combination of local variations consistent set national rules specific rules re sulting can found pre sent AMA rule book Armed new rules set about develop racing package hoped would competitive preparation 1976 Nationals first step course refine model design basic requirements model would rugged streamlined rules allow easy build should possess basic flying characteristics re quired racing plane Bobcat model presented article result effort aircraft fully meets new rules both practice intent features no fancy frills basically both functional practical yet leaves little desired streamlining ship can built either two wing construction techniques shown plans first Bobcat 1975 King Orange Contest Jack sonville Florida built planked wing option used ST-35 PB performed excellently 100-mph range However engine did restart dependably hence did completed Bobcat can built sheeted wing covered Silkspan dope finished clear epoxy wing may Monokote-covered open frame pros cons 40 Model Aviation finish well race happy model flew no bad habits did everthing required good racer tracked well yet maneuvered excellently slowed down well pit stops could ask During winter 19761 set about work engines event June opportunity race model again contest Dayton Ohio During practice flight up leadout failed about 110 mph Instant disaster ruined excellent HP engine also totalled ship Nats month away really put design test barely enough time build another Bobcat would have perfect wouldnt have time much trimming decided try build two would have backup case another disaster further decided make open frame Monokote cov ered save finishing time about three weeks two Bobcats built between getting Goodyears Rat Racers order Nats test flew models Saturday before Nationals Again both flew identical first oneperfect OS engine other HP OS model per formed best both air speed pit stops So decided concentrate prac ticing model Nats now 1 /2 days away Well disaster struck again engine blew wrist pin just after finally everything working 3/16 OD TUBING FROM MECHANICAL FAST FILLFUEL BULB FIGURE NO1 SURGICAL TUBING SEAL 2 I/B HOLES 500 45 13/64 DRILL60 THRU 56001A300 250 130BALL .020 4096 HOLES T 90 SPRING 960 OI8NOM OODIA K \\ 020 PLATE FIT 10 SOLDER IN PLACE K MTL BRASS EXCEPT BALL AND SPRING ARE STEEL TTE 2T 7 7I V IRV 47 17iK~TI April1978 41 Some combinations power plants venturi evaluated development process Nose fuselage contours illustrate attention streamlining Engines used Bobcat turn B-B fiberglass prop pitched 7 in. slightly thinned 19200 20000 rpm way wanted night rebuilt engine spent Sunday afternoon getting broken going right again Monday Nats week Slow Rat thought ready now nerves becoming frazzled got off really well first 70-lap qualifying heat everything going fine until pit stop signaled pit pilot John Ballard brought Bobcat perfectly hit tool box other competitors inadvertently left landing area disaster put very large hole outboard wing rendered model unflyable judges conscientiously rescheduled heat Meanwhile Dick Lambert Paul Curtis helped rebuild wing Hot Stuff Devcon popsicle sticks Fast Cal turned out vain since heat finally re run missed needle setting fin ished ninth place qualifying Only top eight advanced finals After three unpredictable disasters definitely considered giving up Slow Rat However perseverence paid off Michigan Exchange Clubs Annual State Meet Contest finally got gether placed first time 614 three pit stops ran out fuel two laps go OS really running well clocked con sistently 148-150 secs 120 mph Inci dentally Dave Adamisin place second contest HP-powered Bobcat 620 time point very gratified almost solid year model engine development finally paid off OK lets get down building model First must decide Which wing construction will use Both shown plans After building Bobcats both ways must say slight advantages either fully sheeted wing takes longer finish about ounce heavier using Silkspan dope covered clear epoxy However marginally durable youre hurry dont like paint go open-frame construction Monokote Remember will still have paint fuselage stab rudder wing 42 Model Aviation front end showing installation modified HP engine Based upon results engine work described text author supplied sample 36 engines World Engines Midwest HPl same engine installation viewed bottom Shown en gine shut-oft mechanism tank Note placement landing gear Continuedonpage97 Top tail showing tne stitched figure 8 hinging eleva tor puller shut-off wire wire wrapped soldered pushrod Bottom view tail surfaces showing skids mounting tech nique consistency no detail can taken granted entries included Tom Lauries Douglas XB-42 Mixmaster Fernando Ramos Franco-Prussian Bloch powered troop glider Warren Shipps Uppercu-Burnelli UB 14 B Chuck Wests Westland Whirl wind Walt Mooneys Canadair George James Dornier Pfiel Bill Stromans Zeppelin Staaken Preferred power included twin geared motors contra-rotating XB-42 CO2 forthe BlochCox 020s Whirl wind electric Staaken Airspeed Ferry rubber Pfiel Burnelli Canadair Although en tries plagued minor problems failed make required 15-second qual ification flight such courage should ap plauded event won tri motored Airspeed biplane advantage being tested over year half preceeding contest Second went ol perfesser San Diego Walt Mooney Canadair rubber con tained nacelles gave just enough run rousing third Stromans Hercu lean effort Zep ROGd due pendulum stability con trols needed just tad bat tery department four Astro 02s seemed have enough potential fly eight-foot behemoth took off after about 50-foot run Bleaching Dr Martin nifty new way get light letters trim dark back ground comes George James George uses Dr Martins dye white tissue pur ple small brush Clo rox dye bleaches out unwanted areas Rapidograph pen handy small letters make edges trim large letters sharp Try next time want ultra-light job generally use Pres Bruning method sticking opaque letters color-doped tissue using spray rubber cement does add bit heavy some models Until next time thermals Send ideas pix etc pay used Bill Warner 423-C San Vicente Blvd. Santa Monica CA 90402 Bobcat/K ilsdonk continued page 42 ALL GRISH PROPELLERS ARE ENGINEERED TO TRUE 1-IELICAL PITCH AND AIRFOIL FOR EFFICIENCY 2 Blade Tractor 5-3each 5-45/a-35Y2-4304 6-36-4354 747-67-8504 8-48-68-8654 9-4g-6g-7 9-810-410-6854 11-411-611-8$1 12-412-512-6$150 2 Blade Pusher 5Y2-4 6-36-4354 8-6854 9-610-6$1 3 Blade Tractor 6-36-36-4 504 3 Blade Pusher 6-3504 Made polyester boll Color signed no-nonsense airfoil sheeted meets one-inch wing thickness rule need two rib except No 1 Glue ribs 1/4 X 3/s bottom spar leading edge Any new cyanoacrylates Hot-Stuff Zap etc recommended entire wing construction building openframe construction glue trailing edge sheeting followed LE center section rib cap strips fully sheeted wing completely sheeted bottom side bellcrank installed along wing tip skid mounts blind nuts USE TO PROPEL AIR CREATE THRUST AND PROPELLED BY AIR Metallic Aluminum Color 7-67-8$1 8-68-8$125 9-6 10-610-4$150 Pusher 10-6$150 entire top sheeted Dont forget stall pushrods before installing center top section sheeting wing tips can made either 1 balsa double thickness scrap a left over fuselage plank tips carved hollowed out shown Glue Titebond epoxy No wing tip weight required Finish sand sheeted surfaces 150 220 grit garnet paper wing done fuselage stab rudder very straightforward use tank re cessed fuselage shown install outboard plywood doubler first cut tips rib templates plans de product review product review product review cock$t fl coaming__ Cockpit Coaming extruded flexible black vinyl material pre-shaped fit around corner two sizes 3/32and 3/16 dia Price 2 feet size $195 Strut Fairing extruded rigid vinyl two sizes 3/32 1/8 lD packaged two 23 lengths Price size $225 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review THIS FORM ND ATTACH MAILING XI5S~J ABEL FROM RECENT LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept Model Aviation 815 Fifteenth St. NW Washington DC 20005 Check appropriate boxenclose payment C NEW SUBSCRIPTION C CHANGE OF ADDRESS Non-AMA subscription rates $1200 12 months Canada United States possession elsewhere $1400 NAME ADDRESS CITY/STATE ____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW. WASHINGTON DC 20005 April1978 97 GRISH AIRCRAFT TYPE PROPELLERS Made hardwood fully carved true helical pitch airfoil ready sanding ALL SIZES IN18$700 8 & 10 PITCH20800 221000 241300 AT YOUR DEALER RIGHT HAND ROTATION 318 BORE T DISCRETION OF HE PURCHASER 3 E PROPELLERS AT YOUR OALER Os G RUSH ST JOHN INDIANA 46373 CONTROL LINE KITS WEVE GOT EM STARTING T $595 Si Ringmaster S2 FS1 Mustang S3 Yak9 S5 Ringmaster Jr SS Super Ringmaster S12 Flying FenI S13 Baby Ringmaster S15 Rutty Sil P38 Lightning SiS Ringmaster Imper S19 Spitfire S22 Ringmaster Spurts S27 Skylark S28 Sky Shark S29 Ring Jr Flash S30 Beginners Ring 1595 1695 1595 1095 1995 1895 195 2995 1695 2895 3595 1995 3495 1995 1295 595 S31Beginners Mustang595 S32Beg Ring Bipe695 S33Winder1395 S34Beginners Spitfire595 S35Beginners Thunder Jet595 S36Beginners Piper Cub595 S37Beginners tindecker595 S38Beginners Shuestring595 S39Beginners Thunderbult595 S40Beginners Cherukee595 S41Beginners Fnkker Dl695 S42Beginners Hellcat595 S43Beginners FnckeWnlf595 S44Beginners Zern595 545Beginners Messerschmitt595 out slot tank install inboard doubler landing gear use blind nuts engine mount fuel shut-off mount coat-hanger wire rubberbands fuel tank holddown also prefer hardwood tail skid mount blind nuts shown plans After completed fuselage glued wing using either Titebond epoxy making sure fuselage exact center wing perpendicular LE cheek cowl rudder stabilizer glued place again either Tite bond epoxy Make sure tail surfaces parallel square re quired use 3/4 oz fiberglass cloth around cheek cowl K&B surfacing resin surfaces painted followed coat two Hobbypoxy color open areas covered Monokote Solarfilm fully sheeted wing uses same techniques however heavier old-fashioned method 00 Silkspan clear dope talcum powder followed colored dope coat clear epoxy fuel shut off shown similar used Goodyears can fabricated easily /8 aluminum plate lazy hurry commercial W-K Kustom Kraft can substitu ted plans show pusher type shut off what prefer because no solder joints however puller ClMonucunpe C3Mr Mulligan C4The Wacn CsSE5 CSiekker 07 C9Corsair ClONinupert 28 CliGrumman Guardian C12Stearman PT17 C13Great Lakes 1995 1995 2195 2295 2195 2395 2295 2895 2295 2495 STERLING MODELS G ST PHILA PA 19134 no dealer availabte dIrect orders accepted addllio,al charge tar handing shipping tune mininun US. 5125 minimum ostside USl I] Catalog entire line airplane control line mnodei hits it/C scum Trainer kits boat model kits accessories etc Sue enclosed C Secrets Model Airplane Building including design construction cayenne tinishing flying adlusting control systems etc 25c enclosed 0 Secrets Control Line Carrier Flyinn Including preflight soloing stunting Carrier flies regulations Carrier hymn hints control tine inatalfatton instructions 25C enclosed NO checks Only US meney orders currency accepted Name ____________________________ . AddressCity e Zip type may used used two models built quickly Nats Whichever method prefer should actuated full down elevator Bobcat designed around 3-oz old Veco T-21C tank now manufactured Fox tank modi fied either Dons fast-fill use Uniflow vent arrangement like will have fabricate mechanical fast-fill brass bar stock shown Fig No mechanical type provides positive seal irrespective tank pres sure uniflow tank has described times especially Stunt columns will go However far superior conventional assemblies engine consistency though out flight problems encountered event restart pit stops due fuel starvation engine because pressurization allowed prime either exhaust intake would work proved inconsistent time consuming overcome develop ed fueling system shown sliding piece surgical tubing up over fuel fill pipe fuel bulb act seal bulb pushed down mechanical fast-fill air escapes either through single tank vent fuel line tank full fuel therefore escapes through same lines Since fuel being pushed through 5/32 ID pipe bulb cannot vented through 3/32 ID verflow line tank vent hence some must go through fuel supply line engine little practice will de velop touch know hard squeeze bulb during period de livery proper prime engine probably sounds complicated really isnt does work dependably complicated part Slow Rat project engine tried existing 35s 36s course flying observing midwestern Sport Race events over past years Also experiences both Rat Race Goodyear obvi ous needed 36 displacement en gine incorporated ringed piston restarts ball bearings durabil ity Schnuerle porting maximum power Obviously nothing commer cially available time develop something own first approach use basic Supertigre G-21-40 RRV engine used much success 9-10 years ago Rat Race wasnt Schnuerle ported did have other two requireproduct review product review product review New Cannon 1978 five different model lines offered 2 7 channels ranging worlds smallest systems Custom-built 7-Channel test flown covered 1-year warranty models employ new xmitter circuit providing maxi mum legal output 750 milliwatts 72 MHz Newest Mini-Sport System 2-channel dry $11995 5channel nicads $259953-axis single stick 4 5 chan nels available extra cost Standardized plastic xmitter case allows factory conversion Mini-Sport models up 5 channels Any xmitter may converted upwards 4 5 channels 2-stick 3-axis single stick Con version cost $10 retail purchase price difference between original upgrad ed systems Two-axis open-gimbal sticks xmitters systems offer selection servos Flite Packs Full-power Flite Packs use 125 oz servos 4 lbs thrust 500 ma receiver nicads Miniature Flite Packs use 75 oz ser vos 3 lbs thrust choice battery packs 100 250 ma Either pack available separate ly systems available 27 293540 53 72 MHz bands $15 extra 29 3540 53 including new Canadian 72 frequen cies Brochure 25c stamps OK $100 US foreign Cannon RIC Systems1340026 Saticoy St N Hollywood CA 91605 product review product review product review 98 Model Aviation ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em all
Edition: Model Aviation - 1978/04
Page Numbers: 40, 41, 42, 97, 98, 99
This no-nonsense Slow Rat design capable winning performances years come state-of-the-art review made order play engines U John Kilsdonk author making needle valve adjustment before race Note battery strapped arm ACTUALLY Slow Rat Race new seems has around least six seven years am familiar called Sport Race Slow Race Novice Race other local terms designate being slower Rat Race model requirements new event revert back initially used early days Rat Race although specific limitations Rat Race models did resemble present Slow Rats During 1974-1975 AMA CLCB Controline Contest Board input RAC Racing Advisory Commit tee put together combination of local variations consistent set national rules specific rules re sulting can found pre sent AMA rule book Armed new rules set about develop racing package hoped would competitive preparation 1976 Nationals first step course refine model design basic requirements model would rugged streamlined rules allow easy build should possess basic flying characteristics re quired racing plane Bobcat model presented article result effort aircraft fully meets new rules both practice intent features no fancy frills basically both functional practical yet leaves little desired streamlining ship can built either two wing construction techniques shown plans first Bobcat 1975 King Orange Contest Jack sonville Florida built planked wing option used ST-35 PB performed excellently 100-mph range However engine did restart dependably hence did completed Bobcat can built sheeted wing covered Silkspan dope finished clear epoxy wing may Monokote-covered open frame pros cons 40 Model Aviation finish well race happy model flew no bad habits did everthing required good racer tracked well yet maneuvered excellently slowed down well pit stops could ask During winter 19761 set about work engines event June opportunity race model again contest Dayton Ohio During practice flight up leadout failed about 110 mph Instant disaster ruined excellent HP engine also totalled ship Nats month away really put design test barely enough time build another Bobcat would have perfect wouldnt have time much trimming decided try build two would have backup case another disaster further decided make open frame Monokote cov ered save finishing time about three weeks two Bobcats built between getting Goodyears Rat Racers order Nats test flew models Saturday before Nationals Again both flew identical first oneperfect OS engine other HP OS model per formed best both air speed pit stops So decided concentrate prac ticing model Nats now 1 /2 days away Well disaster struck again engine blew wrist pin just after finally everything working 3/16 OD TUBING FROM MECHANICAL FAST FILLFUEL BULB FIGURE NO1 SURGICAL TUBING SEAL 2 I/B HOLES 500 45 13/64 DRILL60 THRU 56001A300 250 130BALL .020 4096 HOLES T 90 SPRING 960 OI8NOM OODIA K \\ 020 PLATE FIT 10 SOLDER IN PLACE K MTL BRASS EXCEPT BALL AND SPRING ARE STEEL TTE 2T 7 7I V IRV 47 17iK~TI April1978 41 Some combinations power plants venturi evaluated development process Nose fuselage contours illustrate attention streamlining Engines used Bobcat turn B-B fiberglass prop pitched 7 in. slightly thinned 19200 20000 rpm way wanted night rebuilt engine spent Sunday afternoon getting broken going right again Monday Nats week Slow Rat thought ready now nerves becoming frazzled got off really well first 70-lap qualifying heat everything going fine until pit stop signaled pit pilot John Ballard brought Bobcat perfectly hit tool box other competitors inadvertently left landing area disaster put very large hole outboard wing rendered model unflyable judges conscientiously rescheduled heat Meanwhile Dick Lambert Paul Curtis helped rebuild wing Hot Stuff Devcon popsicle sticks Fast Cal turned out vain since heat finally re run missed needle setting fin ished ninth place qualifying Only top eight advanced finals After three unpredictable disasters definitely considered giving up Slow Rat However perseverence paid off Michigan Exchange Clubs Annual State Meet Contest finally got gether placed first time 614 three pit stops ran out fuel two laps go OS really running well clocked con sistently 148-150 secs 120 mph Inci dentally Dave Adamisin place second contest HP-powered Bobcat 620 time point very gratified almost solid year model engine development finally paid off OK lets get down building model First must decide Which wing construction will use Both shown plans After building Bobcats both ways must say slight advantages either fully sheeted wing takes longer finish about ounce heavier using Silkspan dope covered clear epoxy However marginally durable youre hurry dont like paint go open-frame construction Monokote Remember will still have paint fuselage stab rudder wing 42 Model Aviation front end showing installation modified HP engine Based upon results engine work described text author supplied sample 36 engines World Engines Midwest HPl same engine installation viewed bottom Shown en gine shut-oft mechanism tank Note placement landing gear Continuedonpage97 Top tail showing tne stitched figure 8 hinging eleva tor puller shut-off wire wire wrapped soldered pushrod Bottom view tail surfaces showing skids mounting tech nique consistency no detail can taken granted entries included Tom Lauries Douglas XB-42 Mixmaster Fernando Ramos Franco-Prussian Bloch powered troop glider Warren Shipps Uppercu-Burnelli UB 14 B Chuck Wests Westland Whirl wind Walt Mooneys Canadair George James Dornier Pfiel Bill Stromans Zeppelin Staaken Preferred power included twin geared motors contra-rotating XB-42 CO2 forthe BlochCox 020s Whirl wind electric Staaken Airspeed Ferry rubber Pfiel Burnelli Canadair Although en tries plagued minor problems failed make required 15-second qual ification flight such courage should ap plauded event won tri motored Airspeed biplane advantage being tested over year half preceeding contest Second went ol perfesser San Diego Walt Mooney Canadair rubber con tained nacelles gave just enough run rousing third Stromans Hercu lean effort Zep ROGd due pendulum stability con trols needed just tad bat tery department four Astro 02s seemed have enough potential fly eight-foot behemoth took off after about 50-foot run Bleaching Dr Martin nifty new way get light letters trim dark back ground comes George James George uses Dr Martins dye white tissue pur ple small brush Clo rox dye bleaches out unwanted areas Rapidograph pen handy small letters make edges trim large letters sharp Try next time want ultra-light job generally use Pres Bruning method sticking opaque letters color-doped tissue using spray rubber cement does add bit heavy some models Until next time thermals Send ideas pix etc pay used Bill Warner 423-C San Vicente Blvd. Santa Monica CA 90402 Bobcat/K ilsdonk continued page 42 ALL GRISH PROPELLERS ARE ENGINEERED TO TRUE 1-IELICAL PITCH AND AIRFOIL FOR EFFICIENCY 2 Blade Tractor 5-3each 5-45/a-35Y2-4304 6-36-4354 747-67-8504 8-48-68-8654 9-4g-6g-7 9-810-410-6854 11-411-611-8$1 12-412-512-6$150 2 Blade Pusher 5Y2-4 6-36-4354 8-6854 9-610-6$1 3 Blade Tractor 6-36-36-4 504 3 Blade Pusher 6-3504 Made polyester boll Color signed no-nonsense airfoil sheeted meets one-inch wing thickness rule need two rib except No 1 Glue ribs 1/4 X 3/s bottom spar leading edge Any new cyanoacrylates Hot-Stuff Zap etc recommended entire wing construction building openframe construction glue trailing edge sheeting followed LE center section rib cap strips fully sheeted wing completely sheeted bottom side bellcrank installed along wing tip skid mounts blind nuts USE TO PROPEL AIR CREATE THRUST AND PROPELLED BY AIR Metallic Aluminum Color 7-67-8$1 8-68-8$125 9-6 10-610-4$150 Pusher 10-6$150 entire top sheeted Dont forget stall pushrods before installing center top section sheeting wing tips can made either 1 balsa double thickness scrap a left over fuselage plank tips carved hollowed out shown Glue Titebond epoxy No wing tip weight required Finish sand sheeted surfaces 150 220 grit garnet paper wing done fuselage stab rudder very straightforward use tank re cessed fuselage shown install outboard plywood doubler first cut tips rib templates plans de product review product review product review cock$t fl coaming__ Cockpit Coaming extruded flexible black vinyl material pre-shaped fit around corner two sizes 3/32and 3/16 dia Price 2 feet size $195 Strut Fairing extruded rigid vinyl two sizes 3/32 1/8 lD packaged two 23 lengths Price size $225 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review THIS FORM ND ATTACH MAILING XI5S~J ABEL FROM RECENT LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept Model Aviation 815 Fifteenth St. NW Washington DC 20005 Check appropriate boxenclose payment C NEW SUBSCRIPTION C CHANGE OF ADDRESS Non-AMA subscription rates $1200 12 months Canada United States possession elsewhere $1400 NAME ADDRESS CITY/STATE ____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW. WASHINGTON DC 20005 April1978 97 GRISH AIRCRAFT TYPE PROPELLERS Made hardwood fully carved true helical pitch airfoil ready sanding ALL SIZES IN18$700 8 & 10 PITCH20800 221000 241300 AT YOUR DEALER RIGHT HAND ROTATION 318 BORE T DISCRETION OF HE PURCHASER 3 E PROPELLERS AT YOUR OALER Os G RUSH ST JOHN INDIANA 46373 CONTROL LINE KITS WEVE GOT EM STARTING T $595 Si Ringmaster S2 FS1 Mustang S3 Yak9 S5 Ringmaster Jr SS Super Ringmaster S12 Flying FenI S13 Baby Ringmaster S15 Rutty Sil P38 Lightning SiS Ringmaster Imper S19 Spitfire S22 Ringmaster Spurts S27 Skylark S28 Sky Shark S29 Ring Jr Flash S30 Beginners Ring 1595 1695 1595 1095 1995 1895 195 2995 1695 2895 3595 1995 3495 1995 1295 595 S31Beginners Mustang595 S32Beg Ring Bipe695 S33Winder1395 S34Beginners Spitfire595 S35Beginners Thunder Jet595 S36Beginners Piper Cub595 S37Beginners tindecker595 S38Beginners Shuestring595 S39Beginners Thunderbult595 S40Beginners Cherukee595 S41Beginners Fnkker Dl695 S42Beginners Hellcat595 S43Beginners FnckeWnlf595 S44Beginners Zern595 545Beginners Messerschmitt595 out slot tank install inboard doubler landing gear use blind nuts engine mount fuel shut-off mount coat-hanger wire rubberbands fuel tank holddown also prefer hardwood tail skid mount blind nuts shown plans After completed fuselage glued wing using either Titebond epoxy making sure fuselage exact center wing perpendicular LE cheek cowl rudder stabilizer glued place again either Tite bond epoxy Make sure tail surfaces parallel square re quired use 3/4 oz fiberglass cloth around cheek cowl K&B surfacing resin surfaces painted followed coat two Hobbypoxy color open areas covered Monokote Solarfilm fully sheeted wing uses same techniques however heavier old-fashioned method 00 Silkspan clear dope talcum powder followed colored dope coat clear epoxy fuel shut off shown similar used Goodyears can fabricated easily /8 aluminum plate lazy hurry commercial W-K Kustom Kraft can substitu ted plans show pusher type shut off what prefer because no solder joints however puller ClMonucunpe C3Mr Mulligan C4The Wacn CsSE5 CSiekker 07 C9Corsair ClONinupert 28 CliGrumman Guardian C12Stearman PT17 C13Great Lakes 1995 1995 2195 2295 2195 2395 2295 2895 2295 2495 STERLING MODELS G ST PHILA PA 19134 no dealer availabte dIrect orders accepted addllio,al charge tar handing shipping tune mininun US. 5125 minimum ostside USl I] Catalog entire line airplane control line mnodei hits it/C scum Trainer kits boat model kits accessories etc Sue enclosed C Secrets Model Airplane Building including design construction cayenne tinishing flying adlusting control systems etc 25c enclosed 0 Secrets Control Line Carrier Flyinn Including preflight soloing stunting Carrier flies regulations Carrier hymn hints control tine inatalfatton instructions 25C enclosed NO checks Only US meney orders currency accepted Name ____________________________ . AddressCity e Zip type may used used two models built quickly Nats Whichever method prefer should actuated full down elevator Bobcat designed around 3-oz old Veco T-21C tank now manufactured Fox tank modi fied either Dons fast-fill use Uniflow vent arrangement like will have fabricate mechanical fast-fill brass bar stock shown Fig No mechanical type provides positive seal irrespective tank pres sure uniflow tank has described times especially Stunt columns will go However far superior conventional assemblies engine consistency though out flight problems encountered event restart pit stops due fuel starvation engine because pressurization allowed prime either exhaust intake would work proved inconsistent time consuming overcome develop ed fueling system shown sliding piece surgical tubing up over fuel fill pipe fuel bulb act seal bulb pushed down mechanical fast-fill air escapes either through single tank vent fuel line tank full fuel therefore escapes through same lines Since fuel being pushed through 5/32 ID pipe bulb cannot vented through 3/32 ID verflow line tank vent hence some must go through fuel supply line engine little practice will de velop touch know hard squeeze bulb during period de livery proper prime engine probably sounds complicated really isnt does work dependably complicated part Slow Rat project engine tried existing 35s 36s course flying observing midwestern Sport Race events over past years Also experiences both Rat Race Goodyear obvi ous needed 36 displacement en gine incorporated ringed piston restarts ball bearings durabil ity Schnuerle porting maximum power Obviously nothing commer cially available time develop something own first approach use basic Supertigre G-21-40 RRV engine used much success 9-10 years ago Rat Race wasnt Schnuerle ported did have other two requireproduct review product review product review New Cannon 1978 five different model lines offered 2 7 channels ranging worlds smallest systems Custom-built 7-Channel test flown covered 1-year warranty models employ new xmitter circuit providing maxi mum legal output 750 milliwatts 72 MHz Newest Mini-Sport System 2-channel dry $11995 5channel nicads $259953-axis single stick 4 5 chan nels available extra cost Standardized plastic xmitter case allows factory conversion Mini-Sport models up 5 channels Any xmitter may converted upwards 4 5 channels 2-stick 3-axis single stick Con version cost $10 retail purchase price difference between original upgrad ed systems Two-axis open-gimbal sticks xmitters systems offer selection servos Flite Packs Full-power Flite Packs use 125 oz servos 4 lbs thrust 500 ma receiver nicads Miniature Flite Packs use 75 oz ser vos 3 lbs thrust choice battery packs 100 250 ma Either pack available separate ly systems available 27 293540 53 72 MHz bands $15 extra 29 3540 53 including new Canadian 72 frequen cies Brochure 25c stamps OK $100 US foreign Cannon RIC Systems1340026 Saticoy St N Hollywood CA 91605 product review product review product review 98 Model Aviation ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em all
Edition: Model Aviation - 1978/04
Page Numbers: 40, 41, 42, 97, 98, 99
This no-nonsense Slow Rat design capable winning performances years come state-of-the-art review made order play engines U John Kilsdonk author making needle valve adjustment before race Note battery strapped arm ACTUALLY Slow Rat Race new seems has around least six seven years am familiar called Sport Race Slow Race Novice Race other local terms designate being slower Rat Race model requirements new event revert back initially used early days Rat Race although specific limitations Rat Race models did resemble present Slow Rats During 1974-1975 AMA CLCB Controline Contest Board input RAC Racing Advisory Commit tee put together combination of local variations consistent set national rules specific rules re sulting can found pre sent AMA rule book Armed new rules set about develop racing package hoped would competitive preparation 1976 Nationals first step course refine model design basic requirements model would rugged streamlined rules allow easy build should possess basic flying characteristics re quired racing plane Bobcat model presented article result effort aircraft fully meets new rules both practice intent features no fancy frills basically both functional practical yet leaves little desired streamlining ship can built either two wing construction techniques shown plans first Bobcat 1975 King Orange Contest Jack sonville Florida built planked wing option used ST-35 PB performed excellently 100-mph range However engine did restart dependably hence did completed Bobcat can built sheeted wing covered Silkspan dope finished clear epoxy wing may Monokote-covered open frame pros cons 40 Model Aviation finish well race happy model flew no bad habits did everthing required good racer tracked well yet maneuvered excellently slowed down well pit stops could ask During winter 19761 set about work engines event June opportunity race model again contest Dayton Ohio During practice flight up leadout failed about 110 mph Instant disaster ruined excellent HP engine also totalled ship Nats month away really put design test barely enough time build another Bobcat would have perfect wouldnt have time much trimming decided try build two would have backup case another disaster further decided make open frame Monokote cov ered save finishing time about three weeks two Bobcats built between getting Goodyears Rat Racers order Nats test flew models Saturday before Nationals Again both flew identical first oneperfect OS engine other HP OS model per formed best both air speed pit stops So decided concentrate prac ticing model Nats now 1 /2 days away Well disaster struck again engine blew wrist pin just after finally everything working 3/16 OD TUBING FROM MECHANICAL FAST FILLFUEL BULB FIGURE NO1 SURGICAL TUBING SEAL 2 I/B HOLES 500 45 13/64 DRILL60 THRU 56001A300 250 130BALL .020 4096 HOLES T 90 SPRING 960 OI8NOM OODIA K \\ 020 PLATE FIT 10 SOLDER IN PLACE K MTL BRASS EXCEPT BALL AND SPRING ARE STEEL TTE 2T 7 7I V IRV 47 17iK~TI April1978 41 Some combinations power plants venturi evaluated development process Nose fuselage contours illustrate attention streamlining Engines used Bobcat turn B-B fiberglass prop pitched 7 in. slightly thinned 19200 20000 rpm way wanted night rebuilt engine spent Sunday afternoon getting broken going right again Monday Nats week Slow Rat thought ready now nerves becoming frazzled got off really well first 70-lap qualifying heat everything going fine until pit stop signaled pit pilot John Ballard brought Bobcat perfectly hit tool box other competitors inadvertently left landing area disaster put very large hole outboard wing rendered model unflyable judges conscientiously rescheduled heat Meanwhile Dick Lambert Paul Curtis helped rebuild wing Hot Stuff Devcon popsicle sticks Fast Cal turned out vain since heat finally re run missed needle setting fin ished ninth place qualifying Only top eight advanced finals After three unpredictable disasters definitely considered giving up Slow Rat However perseverence paid off Michigan Exchange Clubs Annual State Meet Contest finally got gether placed first time 614 three pit stops ran out fuel two laps go OS really running well clocked con sistently 148-150 secs 120 mph Inci dentally Dave Adamisin place second contest HP-powered Bobcat 620 time point very gratified almost solid year model engine development finally paid off OK lets get down building model First must decide Which wing construction will use Both shown plans After building Bobcats both ways must say slight advantages either fully sheeted wing takes longer finish about ounce heavier using Silkspan dope covered clear epoxy However marginally durable youre hurry dont like paint go open-frame construction Monokote Remember will still have paint fuselage stab rudder wing 42 Model Aviation front end showing installation modified HP engine Based upon results engine work described text author supplied sample 36 engines World Engines Midwest HPl same engine installation viewed bottom Shown en gine shut-oft mechanism tank Note placement landing gear Continuedonpage97 Top tail showing tne stitched figure 8 hinging eleva tor puller shut-off wire wire wrapped soldered pushrod Bottom view tail surfaces showing skids mounting tech nique consistency no detail can taken granted entries included Tom Lauries Douglas XB-42 Mixmaster Fernando Ramos Franco-Prussian Bloch powered troop glider Warren Shipps Uppercu-Burnelli UB 14 B Chuck Wests Westland Whirl wind Walt Mooneys Canadair George James Dornier Pfiel Bill Stromans Zeppelin Staaken Preferred power included twin geared motors contra-rotating XB-42 CO2 forthe BlochCox 020s Whirl wind electric Staaken Airspeed Ferry rubber Pfiel Burnelli Canadair Although en tries plagued minor problems failed make required 15-second qual ification flight such courage should ap plauded event won tri motored Airspeed biplane advantage being tested over year half preceeding contest Second went ol perfesser San Diego Walt Mooney Canadair rubber con tained nacelles gave just enough run rousing third Stromans Hercu lean effort Zep ROGd due pendulum stability con trols needed just tad bat tery department four Astro 02s seemed have enough potential fly eight-foot behemoth took off after about 50-foot run Bleaching Dr Martin nifty new way get light letters trim dark back ground comes George James George uses Dr Martins dye white tissue pur ple small brush Clo rox dye bleaches out unwanted areas Rapidograph pen handy small letters make edges trim large letters sharp Try next time want ultra-light job generally use Pres Bruning method sticking opaque letters color-doped tissue using spray rubber cement does add bit heavy some models Until next time thermals Send ideas pix etc pay used Bill Warner 423-C San Vicente Blvd. Santa Monica CA 90402 Bobcat/K ilsdonk continued page 42 ALL GRISH PROPELLERS ARE ENGINEERED TO TRUE 1-IELICAL PITCH AND AIRFOIL FOR EFFICIENCY 2 Blade Tractor 5-3each 5-45/a-35Y2-4304 6-36-4354 747-67-8504 8-48-68-8654 9-4g-6g-7 9-810-410-6854 11-411-611-8$1 12-412-512-6$150 2 Blade Pusher 5Y2-4 6-36-4354 8-6854 9-610-6$1 3 Blade Tractor 6-36-36-4 504 3 Blade Pusher 6-3504 Made polyester boll Color signed no-nonsense airfoil sheeted meets one-inch wing thickness rule need two rib except No 1 Glue ribs 1/4 X 3/s bottom spar leading edge Any new cyanoacrylates Hot-Stuff Zap etc recommended entire wing construction building openframe construction glue trailing edge sheeting followed LE center section rib cap strips fully sheeted wing completely sheeted bottom side bellcrank installed along wing tip skid mounts blind nuts USE TO PROPEL AIR CREATE THRUST AND PROPELLED BY AIR Metallic Aluminum Color 7-67-8$1 8-68-8$125 9-6 10-610-4$150 Pusher 10-6$150 entire top sheeted Dont forget stall pushrods before installing center top section sheeting wing tips can made either 1 balsa double thickness scrap a left over fuselage plank tips carved hollowed out shown Glue Titebond epoxy No wing tip weight required Finish sand sheeted surfaces 150 220 grit garnet paper wing done fuselage stab rudder very straightforward use tank re cessed fuselage shown install outboard plywood doubler first cut tips rib templates plans de product review product review product review cock$t fl coaming__ Cockpit Coaming extruded flexible black vinyl material pre-shaped fit around corner two sizes 3/32and 3/16 dia Price 2 feet size $195 Strut Fairing extruded rigid vinyl two sizes 3/32 1/8 lD packaged two 23 lengths Price size $225 Fourmost Racing Products 4040 24th Ave Forest Grove OR 97116 product review product review product review THIS FORM ND ATTACH MAILING XI5S~J ABEL FROM RECENT LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks re quired change address Attach current MA mailing label check appropriate box mail Subscription Dept Model Aviation 815 Fifteenth St. NW Washington DC 20005 Check appropriate boxenclose payment C NEW SUBSCRIPTION C CHANGE OF ADDRESS Non-AMA subscription rates $1200 12 months Canada United States possession elsewhere $1400 NAME ADDRESS CITY/STATE ____________________________________________ ZIP _______________ MODEL AVIATION 815 FIFTEENTH ST. NW. WASHINGTON DC 20005 April1978 97 GRISH AIRCRAFT TYPE PROPELLERS Made hardwood fully carved true helical pitch airfoil ready sanding ALL SIZES IN18$700 8 & 10 PITCH20800 221000 241300 AT YOUR DEALER RIGHT HAND ROTATION 318 BORE T DISCRETION OF HE PURCHASER 3 E PROPELLERS AT YOUR OALER Os G RUSH ST JOHN INDIANA 46373 CONTROL LINE KITS WEVE GOT EM STARTING T $595 Si Ringmaster S2 FS1 Mustang S3 Yak9 S5 Ringmaster Jr SS Super Ringmaster S12 Flying FenI S13 Baby Ringmaster S15 Rutty Sil P38 Lightning SiS Ringmaster Imper S19 Spitfire S22 Ringmaster Spurts S27 Skylark S28 Sky Shark S29 Ring Jr Flash S30 Beginners Ring 1595 1695 1595 1095 1995 1895 195 2995 1695 2895 3595 1995 3495 1995 1295 595 S31Beginners Mustang595 S32Beg Ring Bipe695 S33Winder1395 S34Beginners Spitfire595 S35Beginners Thunder Jet595 S36Beginners Piper Cub595 S37Beginners tindecker595 S38Beginners Shuestring595 S39Beginners Thunderbult595 S40Beginners Cherukee595 S41Beginners Fnkker Dl695 S42Beginners Hellcat595 S43Beginners FnckeWnlf595 S44Beginners Zern595 545Beginners Messerschmitt595 out slot tank install inboard doubler landing gear use blind nuts engine mount fuel shut-off mount coat-hanger wire rubberbands fuel tank holddown also prefer hardwood tail skid mount blind nuts shown plans After completed fuselage glued wing using either Titebond epoxy making sure fuselage exact center wing perpendicular LE cheek cowl rudder stabilizer glued place again either Tite bond epoxy Make sure tail surfaces parallel square re quired use 3/4 oz fiberglass cloth around cheek cowl K&B surfacing resin surfaces painted followed coat two Hobbypoxy color open areas covered Monokote Solarfilm fully sheeted wing uses same techniques however heavier old-fashioned method 00 Silkspan clear dope talcum powder followed colored dope coat clear epoxy fuel shut off shown similar used Goodyears can fabricated easily /8 aluminum plate lazy hurry commercial W-K Kustom Kraft can substitu ted plans show pusher type shut off what prefer because no solder joints however puller ClMonucunpe C3Mr Mulligan C4The Wacn CsSE5 CSiekker 07 C9Corsair ClONinupert 28 CliGrumman Guardian C12Stearman PT17 C13Great Lakes 1995 1995 2195 2295 2195 2395 2295 2895 2295 2495 STERLING MODELS G ST PHILA PA 19134 no dealer availabte dIrect orders accepted addllio,al charge tar handing shipping tune mininun US. 5125 minimum ostside USl I] Catalog entire line airplane control line mnodei hits it/C scum Trainer kits boat model kits accessories etc Sue enclosed C Secrets Model Airplane Building including design construction cayenne tinishing flying adlusting control systems etc 25c enclosed 0 Secrets Control Line Carrier Flyinn Including preflight soloing stunting Carrier flies regulations Carrier hymn hints control tine inatalfatton instructions 25C enclosed NO checks Only US meney orders currency accepted Name ____________________________ . AddressCity e Zip type may used used two models built quickly Nats Whichever method prefer should actuated full down elevator Bobcat designed around 3-oz old Veco T-21C tank now manufactured Fox tank modi fied either Dons fast-fill use Uniflow vent arrangement like will have fabricate mechanical fast-fill brass bar stock shown Fig No mechanical type provides positive seal irrespective tank pres sure uniflow tank has described times especially Stunt columns will go However far superior conventional assemblies engine consistency though out flight problems encountered event restart pit stops due fuel starvation engine because pressurization allowed prime either exhaust intake would work proved inconsistent time consuming overcome develop ed fueling system shown sliding piece surgical tubing up over fuel fill pipe fuel bulb act seal bulb pushed down mechanical fast-fill air escapes either through single tank vent fuel line tank full fuel therefore escapes through same lines Since fuel being pushed through 5/32 ID pipe bulb cannot vented through 3/32 ID verflow line tank vent hence some must go through fuel supply line engine little practice will de velop touch know hard squeeze bulb during period de livery proper prime engine probably sounds complicated really isnt does work dependably complicated part Slow Rat project engine tried existing 35s 36s course flying observing midwestern Sport Race events over past years Also experiences both Rat Race Goodyear obvi ous needed 36 displacement en gine incorporated ringed piston restarts ball bearings durabil ity Schnuerle porting maximum power Obviously nothing commer cially available time develop something own first approach use basic Supertigre G-21-40 RRV engine used much success 9-10 years ago Rat Race wasnt Schnuerle ported did have other two requireproduct review product review product review New Cannon 1978 five different model lines offered 2 7 channels ranging worlds smallest systems Custom-built 7-Channel test flown covered 1-year warranty models employ new xmitter circuit providing maxi mum legal output 750 milliwatts 72 MHz Newest Mini-Sport System 2-channel dry $11995 5channel nicads $259953-axis single stick 4 5 chan nels available extra cost Standardized plastic xmitter case allows factory conversion Mini-Sport models up 5 channels Any xmitter may converted upwards 4 5 channels 2-stick 3-axis single stick Con version cost $10 retail purchase price difference between original upgrad ed systems Two-axis open-gimbal sticks xmitters systems offer selection servos Flite Packs Full-power Flite Packs use 125 oz servos 4 lbs thrust 500 ma receiver nicads Miniature Flite Packs use 75 oz ser vos 3 lbs thrust choice battery packs 100 250 ma Either pack available separate ly systems available 27 293540 53 72 MHz bands $15 extra 29 3540 53 including new Canadian 72 frequen cies Brochure 25c stamps OK $100 US foreign Cannon RIC Systems1340026 Saticoy St N Hollywood CA 91605 product review product review product review 98 Model Aviation ments worked out using X-40 700 stroke crankshaft dis placement could reduced 357just what wanted As stroke change liner must adjusted upward de creased stroke maintain proper cy linder timing hybrid ST-36RRV performed par standard ST-G-21-35 30% nitro However ringed piston would allow us run 55% nitro still de pendable restarts Therefore able show some improvement over stand ard 35 testing done suction venturi also tried same en gine G-21-29 crank 668 stroke lowered displacement 340 limited success quickly became obvious still needed Schnuerle ports tried barstock engine designed built Henry Nelson using ST lapped piston crank ran extremely well obvi ously too costly looked OS-405R HP 40 using such good success Rat Race decided attempt destroke 40 cranks achieve 36 dis placement After about three weeks failures scrapped parts finally got HP36FR gether dramatically blew doors off everything else proceeded make both OS36RRV FV along HP 36RRV successful except OS36FV managed keep throwing crank bearings out front end turned out HPs required new stoke 667 OS 657 legal displace ments Again liners shimmed HP36FV RV essentially ran same OS performed slightly better both next step determine max imum venturi choke area could get away Initially used nominal 315 diameter stock ST spray bar going through middle tried different lengths angles eventually found 355 diameter ven turi 75 entrance angle worked about best flight testing have since stuck interesting note measured 400 500 rpm about 5-mph gain between 3 15 new 355 diameter have discussions both John Maloney World Engines Jerry Nel son Midwest HP concerning pro duction 36 engines have sup plied both engines specifica tions forward respective factories Meanwhile both Fox K&B now producing Schnuerle 36s although neither ringed dont seem re start consistently Since 1978-79 rules Slow Rat require quantity manufactured engines parts Fox K&B may have lock market least until either OS HP come out ringed-piston ball-bear ing Schnuerle-ported 36 engine found basic 8-8 fiberglass prop Bartel Kelly pitched 7 thinned down little provides best performance engines swing prop between 19200 20000 static ground rpm Whatever engine use either now future think will find Bobcat very efficient no-nonsense model capable winning performances years come Engine Technique/Jehlik continued page 45 year Nats examined engine found okay evidence overheating suggested fabricating tin can cooling shroud wrapped around back cylinder little nitro fuel overheating problem created power loss solved Example Air duct cooled engine really way go enclosed en gines Harold debolt worked up properly designed duct cooling system before 1950 really hasnt improved principle control cooling air forc ing flow laminar way around cylinder achieved nearly cooling front back really believe al enclosed engine models can should incorporate air duct cooling Air/Heat Sink Cooling Usually found helicopters RC cars picture shows heat sink Cox Van heat sink does just what says Attach mass high heat transfer material aluminum lots fins increases radi ator surface cylinder head enables engines operated environ ments dont provide high rates air flow cooling Heat sinks work pretty well care should taken run such engines absolute peak lean settings because heat sinks transfer heat rapidly effective air flow Conse quently can exceed thermal limits burn up pretty rapidly Water Cooling Usually found boat applications engine head fins re placed water jacket flattened wa ter tube cool clamp clamped around cylinder head Water cooling inter esting because provides opportunity really cool engine control opera ting temperatures power settings Ill bet well see some special water cooling ap plication planes cars near fu ture prospects controlling opera ting temperatures tuned pipe short-run maximum-power events too good pass up Some thoughts cooling 1 Dirty engines run hot let engine bake oil dirt outer sur faces cooling air wont able pick up efficiently heat off metal surfaces Clean exterior engine after flying session will stay clean 2 Hot engines run increased clear ances wear out prematurely 3 Engines have practical operating temperature envelope minimum maximum temperatures controlling factor maximum temperature oils fuel can tolerate still proper job lubrication No percen tage oil fuel really doesnt help engine runs too hot Ive never seen practical use over 20% oil providing fuel contains least 5% castor oil engine run over thermal limit April1978 99 Kraftsmanship kit processed AAMCO GOLD BALSAThis Trainer will blow apart hits ground GREATEST B/C BASIC TRAINER Design & Kit ALL TIME Ask over 25000 satisfied builders H-RAY dealers sold themSHALL WE SAY MORE Andresvs Aircraft Model Co Inc US Ete 1& North St Topstield Mass 01983 887-8541 Support AMA Price $3995 kit per dollar em all