LETS TALK about fuel tanks seemingly simple container sole purpose keep raw fuel spilling over beautiful finish Stunters looked closely can seen tanks intimately involved success failure efforts Stunt circle design tank its location airplane manner plumbed affect way engine runs therefore way airplane flies two major types fuel tanks common use Stunt ships plastic RC tanks metal tanks manner type con struction particularly significant since part tankthe skin willhas function containing fuel item importance regard no leaks container shape tank also less critical some might imagine important task shape tank ensure fuel avail able engine fuel pickup tube until very last few drops fuel consumed classic wedge style wherein outboard side formed V shape somewhat helpful ensuring entire fuel load burned However until fuel nearly ex hausted style tanks performance will no better rectangular tank no V ideal cross section Stunt tank should somewhat wider tall classic cross section metal tanks one-inch high two-inches wide results almost exactly ounce fuel inch tank length recently tanks some larger en gines have gone deep 1% allow quantity given length no apparent difference performance Finally have seen owned tanks additions tacked top bottom gain additional volume Again seems have no adverse effect performance Okay tanks type construction shape have little effect performance what important Im glad asked would have short column Location plumbing big two comes tanksthat tank located relationship engine airplane cen terline various tubesfuel feed line tank vent overflow etcare positioned tank Lets discuss location first vertical loca tion gas tank relation engine can altered equalize speed engine upright inverted flight tank below proper position engine will have use effort draw fuel tank mounted higher will result engine QIi2ll FUEL SYSTEMilhiEIfl E1JL SXIEM OECflEASING PnEssuROCONSTANT PRESSUSEUNIFLOW FULL TANKVENTFULL TANKVENT U.FUELIi EVELAZFUEL ToLEVELTO ENGINEENGINE PRESSURECONSTANT PRESSURE II UN IF L OW EMPTY TANKVENT EMPTY TANKVENT FUELI LEVEL-84 LEVELIIFUEL IllToIiTO LOW PRESSURE ENGINE-ENGINE ICONSTAN TPflESSURE II month ever wanted know about fuel tanks Ted starts off basic suction-feed system Top figure illus trates condition existing tank full Lower figure shows system tank nearly empty Fuel pressure outlet tube depends deep fuel tankhigh tank full Note vent tube ends near top running leaner given needle setting go inverted tank will now above its proper location engine will run richer Stunt tanks should made removable adjustable tank can moved up down eliminate difference engine speed between upright inverted flight fore-and-aft location tank impor tant because farther aft tank located farther uphill engine will have draw fuel plane climb distance excessive will cause engine lean out tank should generally mounted close engine can done comfortably Its important understand because fly circle centrifugal force developed model causes fuel empty tank side other fuel pickup tube sucks fuel side tank nearest outside flight circle top bot tom As fuel burned remainder forced against outside wall until depleted fuel thus seeking point tank furth est center circle tank mounted parallel center line airplane looking down model above nose plane pointed Out slightly purposes maintaining line ten sion fuel pickup tube outboard rear cor ner tank will uncovered some fuel still remains tank due the front out board corner tank being further flight circles center arrangement often re sults on-agaln off-again manner some engines will quit Very non-pro-looking eliminate problem mounting tank slight angle thereby ensuring out board aft corner always further cir cles center front outboard corner Although full-bodied Stunters automatically po sition tank directly behind engine profile designs place tank somewhat outboard Stunt engines have adequate fuel draw overcome resulting need draw fuel back against centrifugal force less ideal ar rangement use narrow tank such Taf finders narrow-wedge will reduce problem Lets talk plumbing now tank needs unifiow system looks much same basic suction system except end vent pipe unifiow pipe brought very near mouth outlet tube claimed causes fuel pressure independent depth fuel tank Unifiow vent tube must source vent air tank FUEL PICK-UP TUBE UNI OW/FILL TUBE EXITS TOP INBOARD CcRNER ENDS 3/B INCH FcWARD 1F FUEL PICKHJP OVERFLOW MUST BE CAPPED FER LtJIFLOW OPS typical uniflow-style Stunt tank sketches show lot Ted spends lot time explaining make use good features style tank informa tion can save less-experienced CL Aero batics flier lot grief frustration pierced two tubes fuel go out other lets air go out practical use however generally use three tubes fill/vent and/or uniflow tube through tank filled through air enters displace fuel being burned 2 fuel pickup tube feeds fuel engine 3 An overflow pipe through excess fuel drained tank completely filled during refueling overflow pipe can also serve much useful function will discuss later configuration last two pipes fuel pickup overflow pretty standardized fuel pickup tube comes out front out board corner connected engine flexible tubing Inside tank pickup will extend outboard rear corner halfway between top bottom tank over flow tube comes Out bottom inboard corner tank extends inside tank top board corner locations nearly univer sal vent/uniflow tube complicated device must dealt depth man ner tube installed will determine type fuel delivery system have therefore engine will run feeding tank Continued page 155 62 Model Aviation Control Line Aerobatics Ted Fancher 158 FlyIng Cloud Isle Foster City CA 94404 TYPICAL UNIFLOW TANK 3/4 CUTAWAY VIEW Heres column form matrixes look threeMatrix 1 141626 202232 384050 444656 2834 52 Matrix 2 142016 263228 443840 565052 3422 46 Matrix 3 * 1416 2628 3840 5052 2234 46 20 32 44 56 matrix configurations drop 50-54 MHz frequencies two avail able columns * Configuration 3 courtesy Owen S Black Carmichael CA anyone else can figure out further alternate configurations going nuts please let Russ Kime know Race report Lockport NY weather cool sunny hu midity low Some people felt cool races engines thought weather greatest UPRC United Pylon Racing Circuit Ed Formula record heat time fell no less six times old record belonged Neil Watson 1193 bettered time three heats best 1136 rk Sciandra bettered old rec ord twice best time 1186 Mack heat Neil Watson able hang onto Neils tail let go racking up 1141 p old UPRC top hat top guns UPRC predicted someoneactually someone UPRC would break 115 barrier yearand has done day also little unique almost no mishaps Sport event al though five crashes Formula race results Sport Pylon Expert Class 1 Dick Cowan 1387 2 Rick Paine 1419 3 Ken Gehres 1541 4 Dave Gierke 1444 5 Al Mack 1455 Sport Pylon Standard Class 1 Marlene Niko dem 2077 2 Gary Gau 2125 3 Clarence Ragland 2395 4 Kevin Cuomo 2328 Formula combined results FAI 1 Mark Acrobatic Sport Scale TUCANO iso Custom Built model best its category 40/45 engine 55 Wingspan Compare featcres other ARF models High gloss polyuretnane paint Fiberglass fuselage Birch conered foam wings accessories instalied including special servo engi ne mounts Extremely short time son air ask free catoog otner models avaiable price list AIR CHAMP MODELS2854 NW75 th Ave Miami F 33122- Phone 305 594-5616 Sciandra 1186 2 Rick Paine 1293 3 Neil Watson 1136 4 Al Mack 1141 5 Ed Smith 1391 See races CL Aerobatics/Fancher Continued page 62 two fundamental types fuel deliv ery systems widespread use Stunt ships suc tion systems uniflow systems Which delivery system have depends end vent tube inside tank located better other simply different may appropriate use other See sketches labeled Al through A4 Al A3 illustrate suction principle using sealed bottle vent tube just enters container ends above fluid level fluid outlet tube located bottom container Al fluid level higha full tank situationand pressure outlet tube high result head pressure proportional distance between fluid level outlet tube container nearly empty A3 head pressure low consequently pressure outlet tube low Figures A2 A4 merely illustrate principle perspec tive Stunt tank circular flight ie looking down top tank fuel feed pipe bottom fuel vent just enter ing tank top engine feeding type sys TIRED OF SINGLE CYLINDER VIBRATING ENGINES HERE IS THE ANSWER Vibration worst enemies R/C modeling larger engine vibration will generated Opposing twin cylinders firing simultaneously reduces vibration halt course twins cost manufacture EHS Trading Ltd has brought Ihe AFFORDABLE TWIN Irom Peoples Republic China SMOOTH reliable engine can yours fraction cost single cylinder also looks fits better airplane cheekcowls radial cowls Just think very very few tull scale airplanes using cylinder engine ORDER YOUR TWIN STAR TODAY Yout Airframe valuable Radio will thank tomorrow fly ORDER YOUR TWIN STAR NOW CALL TOLL FREE mare injorniai Ion contact1-800-63HOBBV EHS TRADING LTD808 935-9009 400 HUALANI ST BLDG 13EHAWAII STD TIME HILO HAWAII 9672010 AM-7PM Mom-S 2OO wITHOuT MUFFLER February 1988 155 26283234 38404446 505256 --- TWIN STAR 40 CC/24 CU IN pert ecf Piifl K tern recognizes higher pressure start flight tank full much lower pres sure end fuel head pressure little nothing Since engines needle valve setting fixed will run leaner end flight tank nearly empty begin ning flight tank full Most familiar phenomenon take consideration setting needle ny bit rich start avoid overlean set ting end Now take look sketches BI through B4 illustrate uniflow principle Note vent tube extends deep container nearly fluid outlet tube case top view Stunt tank position nearly adjacent end fuel pickup tube Neatly stated uniflow principle says As long no other sources air system pressure fluid outlet will equal distance head between end uniflow tube fluid outlet notwith standing total amount fluid con tainer What means us no matter full nearly empty tank may pressure sensed engine will remain con stant engine will run consistently same speedwithout leaning-out tendency characteristic suction system sand sand get humps bumps Try Easy SanderTM See Ihe Difference Made select wood sotremely hght sander held lull sheet sand paper Flat sanded accurate sanding surface Large flat surfaces sanding area LH 50 $095 na Note once fluid level below uni flow tube system will revert straight suc tion ensure uniflow system retains its constant input engine certain uniflow tube located very close fuel pickup tube About % forward directly inboard pickup tube normal might interesting note uni flow tube located below outboard fluid outlet will no head pressure fluid flow independent fuel head pressure would cease Any flow Out tank would result engine suction As far en gine concerned end uniflow tube tank Move end tube engine thinks entire tank has moved utilize two delivery systems use help trim airplane optimum per formance exception Wingover ma neuvers requiring the engine last half patternfrom Square Eight ship little heavier ideal could employ suction system know could depend little zip end pattern other hand prefer steady en gine speed throughout flight could use enough Try Easy DrakeoM See Ihe Difference totrewely easy instali Hard find spring steel sod fiber washers Braking action rewains constant during repeated uniflow youre little short power dont want speed end flight using uniflow will allow use larger-diameter venturi engine power fear engine would able draw fuel end run tanks set up accommodate either uniflow suction capping over flow tube have normal uniflow system cap uniflow tube leave overflow open system becomes suction Let em phasize uniflow work overflow must capped both tubes left uncapped system will act pure suction system As matter policy always cap either uniflow overflow tube addition tubes bent slipstream ensure airflow doesnt create siphoning action draw out raw fuel using commercial tank short vents cut short piece fuel tub ing 450 angle install vent tube facing wind important since little bit siphoning may see ground will increase air create negative pres sure tank may cause engine go lean about muffler pressure Certainly Try out may may superior certainly no cure-all can generally expected im prove consistency engine run virtue maintaining constant pressure vent tube likely improve suction sys tem uniflow system Generally speaking high-pressure systems such bladders crankcase pressure taps useful Stunt ships appropri ate applications seeking maximum rpm using intakes too large provide adequate suction classic four-cycle Stunt run doesnt respond well such system Leave em go-fast boys Finally tanks should mounted solidly Fuel foaming should problem nose ship properly constructed vibration kept minimum tank isnt positively lo cated its Murphys law waiting happen can move will move Gotta go now Fly Stunt CL Scale/Boss Continued page 63 directly related fuselage engine nacelles Operations such landing gear retrac tion wheel well doors bomb bay doors re volving turrets permitted event Continued page 158 get shaky whenDo hate field isnt longto install hinges Try Easy HingesnM See Ihe Difference single slot few drops sf C/A gtue its done No gouging pinning hinge pins worry about Incredibly strong Virtually indestructible useLH tOt 20 ninoes 5200 eu 0 Three sizes lIt 5/32 3116LO too tot 102 SOtna~eg4 ERSY5RNDER EA5Y DRAKE EAYHINE nM OKnMP0 Box 1743 Marcos CA 92069 156 Model Aviation Show Colors BECAUSE WERE PROUD OF THEM take lot pride building model So guess color paint youre choosing finish take time put paint chip can Perfect Paint color youre buying color want . take guesswork out finishing Ph 419-797-2208 P0 Box 2480 usky Ohio 44870
Edition: Model Aviation - 1988/02
Page Numbers: 62, 155, 156
LETS TALK about fuel tanks seemingly simple container sole purpose keep raw fuel spilling over beautiful finish Stunters looked closely can seen tanks intimately involved success failure efforts Stunt circle design tank its location airplane manner plumbed affect way engine runs therefore way airplane flies two major types fuel tanks common use Stunt ships plastic RC tanks metal tanks manner type con struction particularly significant since part tankthe skin willhas function containing fuel item importance regard no leaks container shape tank also less critical some might imagine important task shape tank ensure fuel avail able engine fuel pickup tube until very last few drops fuel consumed classic wedge style wherein outboard side formed V shape somewhat helpful ensuring entire fuel load burned However until fuel nearly ex hausted style tanks performance will no better rectangular tank no V ideal cross section Stunt tank should somewhat wider tall classic cross section metal tanks one-inch high two-inches wide results almost exactly ounce fuel inch tank length recently tanks some larger en gines have gone deep 1% allow quantity given length no apparent difference performance Finally have seen owned tanks additions tacked top bottom gain additional volume Again seems have no adverse effect performance Okay tanks type construction shape have little effect performance what important Im glad asked would have short column Location plumbing big two comes tanksthat tank located relationship engine airplane cen terline various tubesfuel feed line tank vent overflow etcare positioned tank Lets discuss location first vertical loca tion gas tank relation engine can altered equalize speed engine upright inverted flight tank below proper position engine will have use effort draw fuel tank mounted higher will result engine QIi2ll FUEL SYSTEMilhiEIfl E1JL SXIEM OECflEASING PnEssuROCONSTANT PRESSUSEUNIFLOW FULL TANKVENTFULL TANKVENT U.FUELIi EVELAZFUEL ToLEVELTO ENGINEENGINE PRESSURECONSTANT PRESSURE II UN IF L OW EMPTY TANKVENT EMPTY TANKVENT FUELI LEVEL-84 LEVELIIFUEL IllToIiTO LOW PRESSURE ENGINE-ENGINE ICONSTAN TPflESSURE II month ever wanted know about fuel tanks Ted starts off basic suction-feed system Top figure illus trates condition existing tank full Lower figure shows system tank nearly empty Fuel pressure outlet tube depends deep fuel tankhigh tank full Note vent tube ends near top running leaner given needle setting go inverted tank will now above its proper location engine will run richer Stunt tanks should made removable adjustable tank can moved up down eliminate difference engine speed between upright inverted flight fore-and-aft location tank impor tant because farther aft tank located farther uphill engine will have draw fuel plane climb distance excessive will cause engine lean out tank should generally mounted close engine can done comfortably Its important understand because fly circle centrifugal force developed model causes fuel empty tank side other fuel pickup tube sucks fuel side tank nearest outside flight circle top bot tom As fuel burned remainder forced against outside wall until depleted fuel thus seeking point tank furth est center circle tank mounted parallel center line airplane looking down model above nose plane pointed Out slightly purposes maintaining line ten sion fuel pickup tube outboard rear cor ner tank will uncovered some fuel still remains tank due the front out board corner tank being further flight circles center arrangement often re sults on-agaln off-again manner some engines will quit Very non-pro-looking eliminate problem mounting tank slight angle thereby ensuring out board aft corner always further cir cles center front outboard corner Although full-bodied Stunters automatically po sition tank directly behind engine profile designs place tank somewhat outboard Stunt engines have adequate fuel draw overcome resulting need draw fuel back against centrifugal force less ideal ar rangement use narrow tank such Taf finders narrow-wedge will reduce problem Lets talk plumbing now tank needs unifiow system looks much same basic suction system except end vent pipe unifiow pipe brought very near mouth outlet tube claimed causes fuel pressure independent depth fuel tank Unifiow vent tube must source vent air tank FUEL PICK-UP TUBE UNI OW/FILL TUBE EXITS TOP INBOARD CcRNER ENDS 3/B INCH FcWARD 1F FUEL PICKHJP OVERFLOW MUST BE CAPPED FER LtJIFLOW OPS typical uniflow-style Stunt tank sketches show lot Ted spends lot time explaining make use good features style tank informa tion can save less-experienced CL Aero batics flier lot grief frustration pierced two tubes fuel go out other lets air go out practical use however generally use three tubes fill/vent and/or uniflow tube through tank filled through air enters displace fuel being burned 2 fuel pickup tube feeds fuel engine 3 An overflow pipe through excess fuel drained tank completely filled during refueling overflow pipe can also serve much useful function will discuss later configuration last two pipes fuel pickup overflow pretty standardized fuel pickup tube comes out front out board corner connected engine flexible tubing Inside tank pickup will extend outboard rear corner halfway between top bottom tank over flow tube comes Out bottom inboard corner tank extends inside tank top board corner locations nearly univer sal vent/uniflow tube complicated device must dealt depth man ner tube installed will determine type fuel delivery system have therefore engine will run feeding tank Continued page 155 62 Model Aviation Control Line Aerobatics Ted Fancher 158 FlyIng Cloud Isle Foster City CA 94404 TYPICAL UNIFLOW TANK 3/4 CUTAWAY VIEW Heres column form matrixes look threeMatrix 1 141626 202232 384050 444656 2834 52 Matrix 2 142016 263228 443840 565052 3422 46 Matrix 3 * 1416 2628 3840 5052 2234 46 20 32 44 56 matrix configurations drop 50-54 MHz frequencies two avail able columns * Configuration 3 courtesy Owen S Black Carmichael CA anyone else can figure out further alternate configurations going nuts please let Russ Kime know Race report Lockport NY weather cool sunny hu midity low Some people felt cool races engines thought weather greatest UPRC United Pylon Racing Circuit Ed Formula record heat time fell no less six times old record belonged Neil Watson 1193 bettered time three heats best 1136 rk Sciandra bettered old rec ord twice best time 1186 Mack heat Neil Watson able hang onto Neils tail let go racking up 1141 p old UPRC top hat top guns UPRC predicted someoneactually someone UPRC would break 115 barrier yearand has done day also little unique almost no mishaps Sport event al though five crashes Formula race results Sport Pylon Expert Class 1 Dick Cowan 1387 2 Rick Paine 1419 3 Ken Gehres 1541 4 Dave Gierke 1444 5 Al Mack 1455 Sport Pylon Standard Class 1 Marlene Niko dem 2077 2 Gary Gau 2125 3 Clarence Ragland 2395 4 Kevin Cuomo 2328 Formula combined results FAI 1 Mark Acrobatic Sport Scale TUCANO iso Custom Built model best its category 40/45 engine 55 Wingspan Compare featcres other ARF models High gloss polyuretnane paint Fiberglass fuselage Birch conered foam wings accessories instalied including special servo engi ne mounts Extremely short time son air ask free catoog otner models avaiable price list AIR CHAMP MODELS2854 NW75 th Ave Miami F 33122- Phone 305 594-5616 Sciandra 1186 2 Rick Paine 1293 3 Neil Watson 1136 4 Al Mack 1141 5 Ed Smith 1391 See races CL Aerobatics/Fancher Continued page 62 two fundamental types fuel deliv ery systems widespread use Stunt ships suc tion systems uniflow systems Which delivery system have depends end vent tube inside tank located better other simply different may appropriate use other See sketches labeled Al through A4 Al A3 illustrate suction principle using sealed bottle vent tube just enters container ends above fluid level fluid outlet tube located bottom container Al fluid level higha full tank situationand pressure outlet tube high result head pressure proportional distance between fluid level outlet tube container nearly empty A3 head pressure low consequently pressure outlet tube low Figures A2 A4 merely illustrate principle perspec tive Stunt tank circular flight ie looking down top tank fuel feed pipe bottom fuel vent just enter ing tank top engine feeding type sys TIRED OF SINGLE CYLINDER VIBRATING ENGINES HERE IS THE ANSWER Vibration worst enemies R/C modeling larger engine vibration will generated Opposing twin cylinders firing simultaneously reduces vibration halt course twins cost manufacture EHS Trading Ltd has brought Ihe AFFORDABLE TWIN Irom Peoples Republic China SMOOTH reliable engine can yours fraction cost single cylinder also looks fits better airplane cheekcowls radial cowls Just think very very few tull scale airplanes using cylinder engine ORDER YOUR TWIN STAR TODAY Yout Airframe valuable Radio will thank tomorrow fly ORDER YOUR TWIN STAR NOW CALL TOLL FREE mare injorniai Ion contact1-800-63HOBBV EHS TRADING LTD808 935-9009 400 HUALANI ST BLDG 13EHAWAII STD TIME HILO HAWAII 9672010 AM-7PM Mom-S 2OO wITHOuT MUFFLER February 1988 155 26283234 38404446 505256 --- TWIN STAR 40 CC/24 CU IN pert ecf Piifl K tern recognizes higher pressure start flight tank full much lower pres sure end fuel head pressure little nothing Since engines needle valve setting fixed will run leaner end flight tank nearly empty begin ning flight tank full Most familiar phenomenon take consideration setting needle ny bit rich start avoid overlean set ting end Now take look sketches BI through B4 illustrate uniflow principle Note vent tube extends deep container nearly fluid outlet tube case top view Stunt tank position nearly adjacent end fuel pickup tube Neatly stated uniflow principle says As long no other sources air system pressure fluid outlet will equal distance head between end uniflow tube fluid outlet notwith standing total amount fluid con tainer What means us no matter full nearly empty tank may pressure sensed engine will remain con stant engine will run consistently same speedwithout leaning-out tendency characteristic suction system sand sand get humps bumps Try Easy SanderTM See Ihe Difference Made select wood sotremely hght sander held lull sheet sand paper Flat sanded accurate sanding surface Large flat surfaces sanding area LH 50 $095 na Note once fluid level below uni flow tube system will revert straight suc tion ensure uniflow system retains its constant input engine certain uniflow tube located very close fuel pickup tube About % forward directly inboard pickup tube normal might interesting note uni flow tube located below outboard fluid outlet will no head pressure fluid flow independent fuel head pressure would cease Any flow Out tank would result engine suction As far en gine concerned end uniflow tube tank Move end tube engine thinks entire tank has moved utilize two delivery systems use help trim airplane optimum per formance exception Wingover ma neuvers requiring the engine last half patternfrom Square Eight ship little heavier ideal could employ suction system know could depend little zip end pattern other hand prefer steady en gine speed throughout flight could use enough Try Easy DrakeoM See Ihe Difference totrewely easy instali Hard find spring steel sod fiber washers Braking action rewains constant during repeated uniflow youre little short power dont want speed end flight using uniflow will allow use larger-diameter venturi engine power fear engine would able draw fuel end run tanks set up accommodate either uniflow suction capping over flow tube have normal uniflow system cap uniflow tube leave overflow open system becomes suction Let em phasize uniflow work overflow must capped both tubes left uncapped system will act pure suction system As matter policy always cap either uniflow overflow tube addition tubes bent slipstream ensure airflow doesnt create siphoning action draw out raw fuel using commercial tank short vents cut short piece fuel tub ing 450 angle install vent tube facing wind important since little bit siphoning may see ground will increase air create negative pres sure tank may cause engine go lean about muffler pressure Certainly Try out may may superior certainly no cure-all can generally expected im prove consistency engine run virtue maintaining constant pressure vent tube likely improve suction sys tem uniflow system Generally speaking high-pressure systems such bladders crankcase pressure taps useful Stunt ships appropri ate applications seeking maximum rpm using intakes too large provide adequate suction classic four-cycle Stunt run doesnt respond well such system Leave em go-fast boys Finally tanks should mounted solidly Fuel foaming should problem nose ship properly constructed vibration kept minimum tank isnt positively lo cated its Murphys law waiting happen can move will move Gotta go now Fly Stunt CL Scale/Boss Continued page 63 directly related fuselage engine nacelles Operations such landing gear retrac tion wheel well doors bomb bay doors re volving turrets permitted event Continued page 158 get shaky whenDo hate field isnt longto install hinges Try Easy HingesnM See Ihe Difference single slot few drops sf C/A gtue its done No gouging pinning hinge pins worry about Incredibly strong Virtually indestructible useLH tOt 20 ninoes 5200 eu 0 Three sizes lIt 5/32 3116LO too tot 102 SOtna~eg4 ERSY5RNDER EA5Y DRAKE EAYHINE nM OKnMP0 Box 1743 Marcos CA 92069 156 Model Aviation Show Colors BECAUSE WERE PROUD OF THEM take lot pride building model So guess color paint youre choosing finish take time put paint chip can Perfect Paint color youre buying color want . take guesswork out finishing Ph 419-797-2208 P0 Box 2480 usky Ohio 44870
Edition: Model Aviation - 1988/02
Page Numbers: 62, 155, 156
LETS TALK about fuel tanks seemingly simple container sole purpose keep raw fuel spilling over beautiful finish Stunters looked closely can seen tanks intimately involved success failure efforts Stunt circle design tank its location airplane manner plumbed affect way engine runs therefore way airplane flies two major types fuel tanks common use Stunt ships plastic RC tanks metal tanks manner type con struction particularly significant since part tankthe skin willhas function containing fuel item importance regard no leaks container shape tank also less critical some might imagine important task shape tank ensure fuel avail able engine fuel pickup tube until very last few drops fuel consumed classic wedge style wherein outboard side formed V shape somewhat helpful ensuring entire fuel load burned However until fuel nearly ex hausted style tanks performance will no better rectangular tank no V ideal cross section Stunt tank should somewhat wider tall classic cross section metal tanks one-inch high two-inches wide results almost exactly ounce fuel inch tank length recently tanks some larger en gines have gone deep 1% allow quantity given length no apparent difference performance Finally have seen owned tanks additions tacked top bottom gain additional volume Again seems have no adverse effect performance Okay tanks type construction shape have little effect performance what important Im glad asked would have short column Location plumbing big two comes tanksthat tank located relationship engine airplane cen terline various tubesfuel feed line tank vent overflow etcare positioned tank Lets discuss location first vertical loca tion gas tank relation engine can altered equalize speed engine upright inverted flight tank below proper position engine will have use effort draw fuel tank mounted higher will result engine QIi2ll FUEL SYSTEMilhiEIfl E1JL SXIEM OECflEASING PnEssuROCONSTANT PRESSUSEUNIFLOW FULL TANKVENTFULL TANKVENT U.FUELIi EVELAZFUEL ToLEVELTO ENGINEENGINE PRESSURECONSTANT PRESSURE II UN IF L OW EMPTY TANKVENT EMPTY TANKVENT FUELI LEVEL-84 LEVELIIFUEL IllToIiTO LOW PRESSURE ENGINE-ENGINE ICONSTAN TPflESSURE II month ever wanted know about fuel tanks Ted starts off basic suction-feed system Top figure illus trates condition existing tank full Lower figure shows system tank nearly empty Fuel pressure outlet tube depends deep fuel tankhigh tank full Note vent tube ends near top running leaner given needle setting go inverted tank will now above its proper location engine will run richer Stunt tanks should made removable adjustable tank can moved up down eliminate difference engine speed between upright inverted flight fore-and-aft location tank impor tant because farther aft tank located farther uphill engine will have draw fuel plane climb distance excessive will cause engine lean out tank should generally mounted close engine can done comfortably Its important understand because fly circle centrifugal force developed model causes fuel empty tank side other fuel pickup tube sucks fuel side tank nearest outside flight circle top bot tom As fuel burned remainder forced against outside wall until depleted fuel thus seeking point tank furth est center circle tank mounted parallel center line airplane looking down model above nose plane pointed Out slightly purposes maintaining line ten sion fuel pickup tube outboard rear cor ner tank will uncovered some fuel still remains tank due the front out board corner tank being further flight circles center arrangement often re sults on-agaln off-again manner some engines will quit Very non-pro-looking eliminate problem mounting tank slight angle thereby ensuring out board aft corner always further cir cles center front outboard corner Although full-bodied Stunters automatically po sition tank directly behind engine profile designs place tank somewhat outboard Stunt engines have adequate fuel draw overcome resulting need draw fuel back against centrifugal force less ideal ar rangement use narrow tank such Taf finders narrow-wedge will reduce problem Lets talk plumbing now tank needs unifiow system looks much same basic suction system except end vent pipe unifiow pipe brought very near mouth outlet tube claimed causes fuel pressure independent depth fuel tank Unifiow vent tube must source vent air tank FUEL PICK-UP TUBE UNI OW/FILL TUBE EXITS TOP INBOARD CcRNER ENDS 3/B INCH FcWARD 1F FUEL PICKHJP OVERFLOW MUST BE CAPPED FER LtJIFLOW OPS typical uniflow-style Stunt tank sketches show lot Ted spends lot time explaining make use good features style tank informa tion can save less-experienced CL Aero batics flier lot grief frustration pierced two tubes fuel go out other lets air go out practical use however generally use three tubes fill/vent and/or uniflow tube through tank filled through air enters displace fuel being burned 2 fuel pickup tube feeds fuel engine 3 An overflow pipe through excess fuel drained tank completely filled during refueling overflow pipe can also serve much useful function will discuss later configuration last two pipes fuel pickup overflow pretty standardized fuel pickup tube comes out front out board corner connected engine flexible tubing Inside tank pickup will extend outboard rear corner halfway between top bottom tank over flow tube comes Out bottom inboard corner tank extends inside tank top board corner locations nearly univer sal vent/uniflow tube complicated device must dealt depth man ner tube installed will determine type fuel delivery system have therefore engine will run feeding tank Continued page 155 62 Model Aviation Control Line Aerobatics Ted Fancher 158 FlyIng Cloud Isle Foster City CA 94404 TYPICAL UNIFLOW TANK 3/4 CUTAWAY VIEW Heres column form matrixes look threeMatrix 1 141626 202232 384050 444656 2834 52 Matrix 2 142016 263228 443840 565052 3422 46 Matrix 3 * 1416 2628 3840 5052 2234 46 20 32 44 56 matrix configurations drop 50-54 MHz frequencies two avail able columns * Configuration 3 courtesy Owen S Black Carmichael CA anyone else can figure out further alternate configurations going nuts please let Russ Kime know Race report Lockport NY weather cool sunny hu midity low Some people felt cool races engines thought weather greatest UPRC United Pylon Racing Circuit Ed Formula record heat time fell no less six times old record belonged Neil Watson 1193 bettered time three heats best 1136 rk Sciandra bettered old rec ord twice best time 1186 Mack heat Neil Watson able hang onto Neils tail let go racking up 1141 p old UPRC top hat top guns UPRC predicted someoneactually someone UPRC would break 115 barrier yearand has done day also little unique almost no mishaps Sport event al though five crashes Formula race results Sport Pylon Expert Class 1 Dick Cowan 1387 2 Rick Paine 1419 3 Ken Gehres 1541 4 Dave Gierke 1444 5 Al Mack 1455 Sport Pylon Standard Class 1 Marlene Niko dem 2077 2 Gary Gau 2125 3 Clarence Ragland 2395 4 Kevin Cuomo 2328 Formula combined results FAI 1 Mark Acrobatic Sport Scale TUCANO iso Custom Built model best its category 40/45 engine 55 Wingspan Compare featcres other ARF models High gloss polyuretnane paint Fiberglass fuselage Birch conered foam wings accessories instalied including special servo engi ne mounts Extremely short time son air ask free catoog otner models avaiable price list AIR CHAMP MODELS2854 NW75 th Ave Miami F 33122- Phone 305 594-5616 Sciandra 1186 2 Rick Paine 1293 3 Neil Watson 1136 4 Al Mack 1141 5 Ed Smith 1391 See races CL Aerobatics/Fancher Continued page 62 two fundamental types fuel deliv ery systems widespread use Stunt ships suc tion systems uniflow systems Which delivery system have depends end vent tube inside tank located better other simply different may appropriate use other See sketches labeled Al through A4 Al A3 illustrate suction principle using sealed bottle vent tube just enters container ends above fluid level fluid outlet tube located bottom container Al fluid level higha full tank situationand pressure outlet tube high result head pressure proportional distance between fluid level outlet tube container nearly empty A3 head pressure low consequently pressure outlet tube low Figures A2 A4 merely illustrate principle perspec tive Stunt tank circular flight ie looking down top tank fuel feed pipe bottom fuel vent just enter ing tank top engine feeding type sys TIRED OF SINGLE CYLINDER VIBRATING ENGINES HERE IS THE ANSWER Vibration worst enemies R/C modeling larger engine vibration will generated Opposing twin cylinders firing simultaneously reduces vibration halt course twins cost manufacture EHS Trading Ltd has brought Ihe AFFORDABLE TWIN Irom Peoples Republic China SMOOTH reliable engine can yours fraction cost single cylinder also looks fits better airplane cheekcowls radial cowls Just think very very few tull scale airplanes using cylinder engine ORDER YOUR TWIN STAR TODAY Yout Airframe valuable Radio will thank tomorrow fly ORDER YOUR TWIN STAR NOW CALL TOLL FREE mare injorniai Ion contact1-800-63HOBBV EHS TRADING LTD808 935-9009 400 HUALANI ST BLDG 13EHAWAII STD TIME HILO HAWAII 9672010 AM-7PM Mom-S 2OO wITHOuT MUFFLER February 1988 155 26283234 38404446 505256 --- TWIN STAR 40 CC/24 CU IN pert ecf Piifl K tern recognizes higher pressure start flight tank full much lower pres sure end fuel head pressure little nothing Since engines needle valve setting fixed will run leaner end flight tank nearly empty begin ning flight tank full Most familiar phenomenon take consideration setting needle ny bit rich start avoid overlean set ting end Now take look sketches BI through B4 illustrate uniflow principle Note vent tube extends deep container nearly fluid outlet tube case top view Stunt tank position nearly adjacent end fuel pickup tube Neatly stated uniflow principle says As long no other sources air system pressure fluid outlet will equal distance head between end uniflow tube fluid outlet notwith standing total amount fluid con tainer What means us no matter full nearly empty tank may pressure sensed engine will remain con stant engine will run consistently same speedwithout leaning-out tendency characteristic suction system sand sand get humps bumps Try Easy SanderTM See Ihe Difference Made select wood sotremely hght sander held lull sheet sand paper Flat sanded accurate sanding surface Large flat surfaces sanding area LH 50 $095 na Note once fluid level below uni flow tube system will revert straight suc tion ensure uniflow system retains its constant input engine certain uniflow tube located very close fuel pickup tube About % forward directly inboard pickup tube normal might interesting note uni flow tube located below outboard fluid outlet will no head pressure fluid flow independent fuel head pressure would cease Any flow Out tank would result engine suction As far en gine concerned end uniflow tube tank Move end tube engine thinks entire tank has moved utilize two delivery systems use help trim airplane optimum per formance exception Wingover ma neuvers requiring the engine last half patternfrom Square Eight ship little heavier ideal could employ suction system know could depend little zip end pattern other hand prefer steady en gine speed throughout flight could use enough Try Easy DrakeoM See Ihe Difference totrewely easy instali Hard find spring steel sod fiber washers Braking action rewains constant during repeated uniflow youre little short power dont want speed end flight using uniflow will allow use larger-diameter venturi engine power fear engine would able draw fuel end run tanks set up accommodate either uniflow suction capping over flow tube have normal uniflow system cap uniflow tube leave overflow open system becomes suction Let em phasize uniflow work overflow must capped both tubes left uncapped system will act pure suction system As matter policy always cap either uniflow overflow tube addition tubes bent slipstream ensure airflow doesnt create siphoning action draw out raw fuel using commercial tank short vents cut short piece fuel tub ing 450 angle install vent tube facing wind important since little bit siphoning may see ground will increase air create negative pres sure tank may cause engine go lean about muffler pressure Certainly Try out may may superior certainly no cure-all can generally expected im prove consistency engine run virtue maintaining constant pressure vent tube likely improve suction sys tem uniflow system Generally speaking high-pressure systems such bladders crankcase pressure taps useful Stunt ships appropri ate applications seeking maximum rpm using intakes too large provide adequate suction classic four-cycle Stunt run doesnt respond well such system Leave em go-fast boys Finally tanks should mounted solidly Fuel foaming should problem nose ship properly constructed vibration kept minimum tank isnt positively lo cated its Murphys law waiting happen can move will move Gotta go now Fly Stunt CL Scale/Boss Continued page 63 directly related fuselage engine nacelles Operations such landing gear retrac tion wheel well doors bomb bay doors re volving turrets permitted event Continued page 158 get shaky whenDo hate field isnt longto install hinges Try Easy HingesnM See Ihe Difference single slot few drops sf C/A gtue its done No gouging pinning hinge pins worry about Incredibly strong Virtually indestructible useLH tOt 20 ninoes 5200 eu 0 Three sizes lIt 5/32 3116LO too tot 102 SOtna~eg4 ERSY5RNDER EA5Y DRAKE EAYHINE nM OKnMP0 Box 1743 Marcos CA 92069 156 Model Aviation Show Colors BECAUSE WERE PROUD OF THEM take lot pride building model So guess color paint youre choosing finish take time put paint chip can Perfect Paint color youre buying color want . take guesswork out finishing Ph 419-797-2208 P0 Box 2480 usky Ohio 44870