CONTROL LINE SPEED NEW INFORMATION ideas products column sometimes hard come keep trying have suggestions requests please write let know Robarts Snake Oil mentioned product last pre-Nats column now have additional info some test results Robart has several compounds contain low-friction additive addition fuel additive may want try RIC fuel treatment #50-02 comes neat plastic bottle automatically measures proper amount add fuel just squeeze bottle forces shot smaller section can poured fuel jug takes about shot per quart fuel -scale fliers might want try too number 50-06 full-strength oil additive mixing commercial gasoline suit gas-burning ignition engines Proper mixing ratios printed label have know what percentage oil want particular engine nicest items #50-01 ounce squirt bottle after-mn oil lubricates engine leaving nice free next run protects moisture fits neatly toolbox like best however RC spray lubricant #50-05a solution repels replaces moisture well lubricating comes pressurized can pressure forces spray engines bearings whatever wherever need very small squirt thats necessary force some lube front bearing instance special lubricants restricted RC engines work great bicycles fishing reels electric motors lawn mowers household chore well Larger containers available transmissions gear boxes crankcase car small tube grease available works great bicycle wheel bearings RC car gear boxes Does work Does fuel additive really increase power rpm performance find out sure put two fuel tanks connected tee engine test stand engine could pinch off either line wanted could start engine set needle measure rpm standard fuel open line modified fuel stopping engine check increase have tried few ringed RC engines speed racing engines since competing fuels restricted first mounted OS 40 fired up set needle peak rpm lean opened line modified fuel some increase nothing like 1000 rpm increase some fliers have claimed ran several other engines about same results did get increase rpm something like 100 200 rpm too bad considering sport engines turning normal sport-type props Its difficult improve lubrication engines anyway thin layer hot oil really slippery intro thing power main point using Snake Oil bonds bearing surfaces protect during high rpm lean runs reduces wear increases reliability engine makes starting easier extends life engine quick impressive demonstration its effectiveness find ABC engine tight squeaks tura over Just give shot Snake Oil flip againyoull notice difference RC fliers set engines lean takeoff sag about halfway through flight during maneuvers puts highest possible stress engine since putting out maximum power doesnt have necessary lubrication cooling Robarts additive can help protect engine parts during lean runs providing tenacious layer oil bearing surfaces get information test results Ill keep posted like go flea markets antique shops well swap shops once some engine old kit shows up places Sycamore Illinois thresheree antique gas-engine tractor show couple weeks ago always have flea market too found original kit Stanzel Tiger Shark g-line control model new conditionnever out box model produced just before Jim Walker patented U-Control about 54 years old Im going build itit too nice coliectiblebut might fun build replica still old kits old engines out once stumble onto Getting back modem things let tell about neat gadget saw Nats Bob Fogg top AIvIA Racing competitor Fogg-Sheehan Racing Team has teamed up Carlos Aloise fly Speed last couple years guys have neat airplanes neat engines neat gadgets Look photo Bobs prop trimmer block aluminum holes block has chunk linen phenolic bolted end trim prop appropriate pin put prop hub pin inserted desired hole tips prop extend beyond phenolic block sanded off leaving blade same length sanding block rubs against phenolic very wear resistant stays square end sandpaper trims prop holes along upper edge give prop diameter four ten inches additional hole across block increases diameter tenth inch Bob can trim prop certain diameter wants make additional props same diameter engine load January1994 125 Bob Fogg built prop-trimmer fixture give exact length blade Continued page 1S2 Dub Jett former Speed flier World Champion Pylon pilot designed producing Jett 40 racing engine Russian Stels 21 engine first US shown Nats Scott Newkirk run time photo Mike Wisniewski holds winning 21 Sport Speed engine built Grampa Bill parts K&B Sportster 20 FF Indoor/Tenny Continued page 151 about prop blades built form angular difference between two blade stations remain same blade rotated shortened discussed below Modifying Existing Props us have constructed props using tissue socket hub allows us change prop blades rotate blades different angle matched sets different diameter possible tailor old props new models Simply rotating blades new angle makes minor adjustments existing prop Lets examine what happens 20inch-pitch prop computed above Assume have cut inch out center prop spars leave 15 inches diameter Using tissue sockets can splice two blades together following chart compares blade angle vs diameter data previously shown pitch resulting four kinds change prop blade can rotated lower angle higher angle can shortened also can shortened rotated higher angle computations show results rotating blade five degrees five degrees less shortening 16-inch diameter 15 inches blade one-halfinch shorter right column combines effect shortening blade increasing angle five degrees case computation begins angle blade element shown original chart computed result same segment shown change condition right CL AerobaticslMcMillan Continued page 123 Tech Tips Last year discussed sealing control surface hinge lines extremely effective trimming tool Because chances good will help no question should try new planes Although doesnt help planes wont know until give go benefit prevention funnies Windy Urtnowski calls outboard wing rebuilt Caudron popped up top inside outside rounds First sealed CL Speed/Lee Continued paqe 125 needle setting wont change Different pins required different props stored hole end block kept threaded brass plug terrific accessory ease prop modification increase flight repeatability Another interesting thing Nats Bill Wisniewskis 21 K&B engine used grandson Mike 21 Sport Speed Bill used sleeve piston Sportster 20 drum rotor space between hinges wing still behaved same desperation ran continuous strip root tip funny gone best could figure out hinge cutouts tip bleeding air small things can real killers main reason brought up pass information found unlikely place using 3Ms plastic tape satisfactory adhesive effective because low tack however since tape bit thick controls somewhat stiff led search something better Continued page 165 rear end used marine version engine built ball-bearing crankshaft crankcase trouble conrodthe bronze bushing kept going outso pressed high-silicon aluminum bushing worked great engine ran very well K&B engines now have clearance conrods much 005 being used lower end engine performance reliability better ever See Nats photos couple new engines Wiley 40 Jett 40 Ill try get performance information future column h itch after change DiaBlade Angle 2 726 4 579 6 467 8 385 10 325 12 279 14 244 16 217 152 166 168 166 163 159 155 150 266 246 239 238 241 244 248 253 15 dia 149 175 183 187 190 191 192 214 215 219 224 229 234 239 Figure 3 graphs pitch distribution rotated blades comparison standard 20-inch helical blade using variable pitch props think about widely pitch varies over range allow angle change may profit planning what pitch block build blades use high-pitch block equal upper limit setting lower settings will have center blade doing work efficient Im sure anyone knows sure interesting think about Model Aviation 4
Edition: Model Aviation - 1994/01
Page Numbers: 125, 152
CONTROL LINE SPEED NEW INFORMATION ideas products column sometimes hard come keep trying have suggestions requests please write let know Robarts Snake Oil mentioned product last pre-Nats column now have additional info some test results Robart has several compounds contain low-friction additive addition fuel additive may want try RIC fuel treatment #50-02 comes neat plastic bottle automatically measures proper amount add fuel just squeeze bottle forces shot smaller section can poured fuel jug takes about shot per quart fuel -scale fliers might want try too number 50-06 full-strength oil additive mixing commercial gasoline suit gas-burning ignition engines Proper mixing ratios printed label have know what percentage oil want particular engine nicest items #50-01 ounce squirt bottle after-mn oil lubricates engine leaving nice free next run protects moisture fits neatly toolbox like best however RC spray lubricant #50-05a solution repels replaces moisture well lubricating comes pressurized can pressure forces spray engines bearings whatever wherever need very small squirt thats necessary force some lube front bearing instance special lubricants restricted RC engines work great bicycles fishing reels electric motors lawn mowers household chore well Larger containers available transmissions gear boxes crankcase car small tube grease available works great bicycle wheel bearings RC car gear boxes Does work Does fuel additive really increase power rpm performance find out sure put two fuel tanks connected tee engine test stand engine could pinch off either line wanted could start engine set needle measure rpm standard fuel open line modified fuel stopping engine check increase have tried few ringed RC engines speed racing engines since competing fuels restricted first mounted OS 40 fired up set needle peak rpm lean opened line modified fuel some increase nothing like 1000 rpm increase some fliers have claimed ran several other engines about same results did get increase rpm something like 100 200 rpm too bad considering sport engines turning normal sport-type props Its difficult improve lubrication engines anyway thin layer hot oil really slippery intro thing power main point using Snake Oil bonds bearing surfaces protect during high rpm lean runs reduces wear increases reliability engine makes starting easier extends life engine quick impressive demonstration its effectiveness find ABC engine tight squeaks tura over Just give shot Snake Oil flip againyoull notice difference RC fliers set engines lean takeoff sag about halfway through flight during maneuvers puts highest possible stress engine since putting out maximum power doesnt have necessary lubrication cooling Robarts additive can help protect engine parts during lean runs providing tenacious layer oil bearing surfaces get information test results Ill keep posted like go flea markets antique shops well swap shops once some engine old kit shows up places Sycamore Illinois thresheree antique gas-engine tractor show couple weeks ago always have flea market too found original kit Stanzel Tiger Shark g-line control model new conditionnever out box model produced just before Jim Walker patented U-Control about 54 years old Im going build itit too nice coliectiblebut might fun build replica still old kits old engines out once stumble onto Getting back modem things let tell about neat gadget saw Nats Bob Fogg top AIvIA Racing competitor Fogg-Sheehan Racing Team has teamed up Carlos Aloise fly Speed last couple years guys have neat airplanes neat engines neat gadgets Look photo Bobs prop trimmer block aluminum holes block has chunk linen phenolic bolted end trim prop appropriate pin put prop hub pin inserted desired hole tips prop extend beyond phenolic block sanded off leaving blade same length sanding block rubs against phenolic very wear resistant stays square end sandpaper trims prop holes along upper edge give prop diameter four ten inches additional hole across block increases diameter tenth inch Bob can trim prop certain diameter wants make additional props same diameter engine load January1994 125 Bob Fogg built prop-trimmer fixture give exact length blade Continued page 1S2 Dub Jett former Speed flier World Champion Pylon pilot designed producing Jett 40 racing engine Russian Stels 21 engine first US shown Nats Scott Newkirk run time photo Mike Wisniewski holds winning 21 Sport Speed engine built Grampa Bill parts K&B Sportster 20 FF Indoor/Tenny Continued page 151 about prop blades built form angular difference between two blade stations remain same blade rotated shortened discussed below Modifying Existing Props us have constructed props using tissue socket hub allows us change prop blades rotate blades different angle matched sets different diameter possible tailor old props new models Simply rotating blades new angle makes minor adjustments existing prop Lets examine what happens 20inch-pitch prop computed above Assume have cut inch out center prop spars leave 15 inches diameter Using tissue sockets can splice two blades together following chart compares blade angle vs diameter data previously shown pitch resulting four kinds change prop blade can rotated lower angle higher angle can shortened also can shortened rotated higher angle computations show results rotating blade five degrees five degrees less shortening 16-inch diameter 15 inches blade one-halfinch shorter right column combines effect shortening blade increasing angle five degrees case computation begins angle blade element shown original chart computed result same segment shown change condition right CL AerobaticslMcMillan Continued page 123 Tech Tips Last year discussed sealing control surface hinge lines extremely effective trimming tool Because chances good will help no question should try new planes Although doesnt help planes wont know until give go benefit prevention funnies Windy Urtnowski calls outboard wing rebuilt Caudron popped up top inside outside rounds First sealed CL Speed/Lee Continued paqe 125 needle setting wont change Different pins required different props stored hole end block kept threaded brass plug terrific accessory ease prop modification increase flight repeatability Another interesting thing Nats Bill Wisniewskis 21 K&B engine used grandson Mike 21 Sport Speed Bill used sleeve piston Sportster 20 drum rotor space between hinges wing still behaved same desperation ran continuous strip root tip funny gone best could figure out hinge cutouts tip bleeding air small things can real killers main reason brought up pass information found unlikely place using 3Ms plastic tape satisfactory adhesive effective because low tack however since tape bit thick controls somewhat stiff led search something better Continued page 165 rear end used marine version engine built ball-bearing crankshaft crankcase trouble conrodthe bronze bushing kept going outso pressed high-silicon aluminum bushing worked great engine ran very well K&B engines now have clearance conrods much 005 being used lower end engine performance reliability better ever See Nats photos couple new engines Wiley 40 Jett 40 Ill try get performance information future column h itch after change DiaBlade Angle 2 726 4 579 6 467 8 385 10 325 12 279 14 244 16 217 152 166 168 166 163 159 155 150 266 246 239 238 241 244 248 253 15 dia 149 175 183 187 190 191 192 214 215 219 224 229 234 239 Figure 3 graphs pitch distribution rotated blades comparison standard 20-inch helical blade using variable pitch props think about widely pitch varies over range allow angle change may profit planning what pitch block build blades use high-pitch block equal upper limit setting lower settings will have center blade doing work efficient Im sure anyone knows sure interesting think about Model Aviation 4