Radio Control Scale Bob Dolly Wischer CABLE SYSTEMS use cables operate elevators rudder now rather common real trick assembling such system matter Scale realism visible external por tions cables should enter through fuselage side proper locations elevator cables cross unusual crossover point should right spot relative cable length other external features requires bit planning possible helpful have some idea cable layout routing prototype aircraft Lacking vital information project line cable photo three-view drawing help determine location internal bellcrank forward ends ca bles connected relatively simple matter install models bellcrank assembly proper location usual method operation full-sized aircraft pivot tube across fuselage bellcrank welded end lever welded near tube center connection cables pushrod control stick model tube could replaced hardwood dowel plywood bellcranks cemented near end pivots drill 062-in diameter hole end dowel insert short lengths 062-in music wire bearings support outer ends wires plywood bearings drilled running fit wires Near dowels center cement another plywood lever connect pushrod servo Details producing cable-operated system thoroughly covered December 1985 column subject being reviewed because problem new Douglas M-2 Mailplane recently came light M-2 has pair cables half elevator Noth ing unusual about visit National Air Space Museum see existing prototype discovered ca bles ran over pulleys stabilizer leading edge - This done give both upper lower cables equal length would maintain tension regardless position through elevator travel Obviously such prominent feature needed Bob liulsinga scratch-built Fairchild 24W 1/scaie L Models power Quadra 50 landing gear welded 4130 steel tubing Finish K&B epoxy over Worldtex took him 20 months build Bob Wisohers new Douglas Maliplane R has four control cables elevatorswhich caused some grief explains column Wingspan 1870 weight 1812 lb Power Enya 120 four-stroke Ace Nylite ii on-board glow ignition cockpit completely detailed has operating rudder barand controi stick Hansa-Brandenburg W-29 1 lathe iatest project Ralph Beck 1/B-scale spans 886 uses 0861 power Ralph used 8 rolls masking tape paint iozenge-pattern camoufiage wings tail surfaces fioats fuselage top H ighiy-detailed construction drawings available Ralph Beck Rt 2 Box 131 Beloit WI 53511 Quarter-scale Aeronca KCA R work Pat Massey its OS Gemini 180 four-stroke twin has dummy cylinders simulate 50-horsepower Continental engine Span 108 weight 1 51/2 lb 44 Model Aviation Homemade music wire springs mandreistheywere wound Top bottom 281 in-dlameter mandrel winds spring 43-in 00 1/4-in-diametersteel rod mandrel 22turn springs tubular shock struts 1 86-in-diameter mandrel used wind springs Douglas Mailpiane shock struts aluminum mandrel 062 047-in music wire pressed ends wind tiny 016-wire springs shown latter used tension rigging wires Douglas Set screws clamp first turn 016 wire duplicated model However pulleys quite free-running presence model introduced four friction points usual servos no trouble overcoming added friction surfaces moved through extremes motion full Up full Down problem became evident however elevators teased around neutral surface would move up example transmitter stick moved very small amount Up direction elevator would completely return neutral control stick releasedtoo much friction sys tem Tightening cables excessively made condition worse Something done maintain controllability near elevator neutral position avoid predictable problems air model would continuously hunting level flight worst condition obviously during land ing Up-elevator applied flare three-point position After raising nose proper wing-angle attack necessary reduce Up-elevator just before wheels touch down depending upon speed speed slightly high elevators cant quickly neu tralized result climb followed stall could produce abrupt landings otherwise known arrival very least damage broken prop worst nose landing gear suffer damage Since flying done small movements control surfaces around neutral rather larger excur sions its important have reliable repeat able neutral solution energetic servos par ticularly good resolution around neu tral Several such servos intended large air craft sailboats available ordinarily require large batteries because high current draw chosen servo Ace Atlas assembled kits price right have 45 in-oz output torque utilize amplifier gives less degree resolution arent small because large diameter 20mm motor supplies high torque current drain isnt excessive regular 550 mAh batteries sufficient vast spaces inside Scale models arent concerned servo size Most important elevators now neutralize completely teased small incremental movements model doesnt gallop over sky search true straight-and-level flight can now have lightweight positive cable system minus nuisance factor poor elevator centering Any us have flown old servos past will remember difficulties attain ing stable flight poor resolution Some Scale models didnt really perform well until having new servos installed years after built Small servos large airplanes led similar troubles variety high-quality ser vos currently hand has made smooth con trollability Scale models reality Spring winding reader asked ex planation technique used making springs special applications area Ace Hardware store has supply springs stockboth compression tension typesand quite often able find suitable springs modeling purposes everyone doesnt have convenient hardware store neighborhood times off-the-shelf springs dont fit application because size load characteristics times like helps know basics making own springs Seven Scale models employed compression springs Continued page 143 1/6 scale fully poseable 1211 action pilots dressed removable fabric flight gear time No painting assembly required WWI & Civilian weigh 6 oz WWII pilot has removable Parachute Mae West weighs 8 oz Add $325 per figure P&H calif res add sales tax Allow 10 days delivery Note Pilots can also fly 1/5 scale ships Send Check money order MGA Enterprises PO Box 626 DeptA Fresno Calif 93709 DRILL MOUNT MASTER Engine hole guide drilling jig Have ever tried accurately lay Out engine mounting holes engine mount Have ever tried drill tap holes have will appreciate DRILL MOUNT MASTER No LAYING OT OF HOLES REQUIRED WHEN USING THE DRILL MOUNT MASTER EXCLUSIVE JTEC TUNE HOLE GUIDE SYSTEM GIVES PERFECTLY MATCHED HOLES EVERY TIME THE DRILLING JIG HOLDS THE ENGINE MOUNT FIRMLY FOR EASY DRILLING AND TAPPING Two SIZES FRONT PRESSURE PLATES TO HOLDOnly ANY ENGINE MOUNT FROM 15 TO 1202995 DRILL MOUNT MASTER IS CAST ALUMINUM MACHINED AND BRIGH POLISHED MADE TO LAST rrol avorloble hobby shop 050th DIRSCT wwrredbate shlprrvenl Check MO VIs MOor COD accepted Add $250 UPS S20O COO 6% saks ta Calif resIdent m9@ pilots m mm April 1987 45 Reverse Knife Edge Flight namely really strange Aerobatic maneuver requiring airplane large lateral area and/or high thrust Lets respond respective Contest Board members feel about proposals cleared Initial Vote hurdle Otherwise have ourselves blame votes go wrong way Nats schedule year will require lot us used late July/early August Nats starting date pay attention July 11 19 dates least two weeks earlier usual Schedule vacation early folks Another impact contests usually Nats tune-ups may too late year Unfortunately may cause some con tests cancelled due direct conflicts because dates proximity Nats know wont able go least contest always look forward attending July last note caption picture Paul Verger Lafayette LA appeared February issue said aileron servo Pauls airplane quit vertical-downward part Square Loop s Have ever seen maneuvers s would real challenge Can see corner end vertical-downward part Tough maneuver Sorry just typo should have s Ron Van Putte 111 Sleepy Oaks Rd Ft Walton Beach FL 32548 landing-gear struts made home Winding springs mandrel really simple operation Anyone access lathe can pro duce springs quantity short time lathe spindle slowed means belt pulleys back gears give speed about revolution per second Slower better possible lathe isnt available mandrel can supported hardwood block clamped vise crank lever fastened end setscrew rotate mandrel manually Lever length about eight inches foot satisfactory winding springs light music wire up 062-in di ameter Drill cross hole through mandrel accept wire size chosen spring Bend music wire end 900 inserted cross hole Whether lathe-wound hand-cranked operation requires two persons example spring about 375-in outside diameter having 062-in music wire 25 turns will use almost three-foot length music wire Tension must applied free end wire force wire closely around mandrel spring wound personthe stronger heavier twostretches wire tightly other operates lathe On-Off switch turns crank have found reliable way grip wires free end plier vise-grip type heavy linemans plier likely slip due tension momentary relaxation operator happens free end wire will whip around arc can easily MORE POWEi1 WITH LESS NOISE four-cycle measuring up expectations read Make engine before Make 60 120 four-stroke less means 1 Quieter glow 2 More mellow sounding four-cycle 3 More usable power both 4 Highest power-to-weight ratio 5 The lowest idle ever 6 Increase mileage up 4 times 7 Runs cooler glow 8 No glowplugs fail 9 Increased reliability 10 Fuel available concentrate Conversion kits available 049 30 cid Schnuerle ported engines Its sim ple just change heads fuel What waiting Dust off two-cycle DIESELIZE Send self-addressed stamped enve lope $100 infoation call 203-877-1670 between 730 pm and 930 pm EST DAVIS DIESEL DEVELOPMENT PO Box 141 Milford CT 06460 leader quiet combustion technology since 1976 April1987143 RC Scale/Wischers Continued page 45 responding advertisers mention read about ModelAviation cause serious damage body parts Always wear eye protection wind heavy wire 062-in diameter example person pulling vise-grip plier must use maximum muscle weight force wire closely around mandrel com pletely wound spring will open slightly larger outside diameter insufficient stretch ing during winding spring-back will exces sive resulting spring will probably fit space allotted Lighter wire needs less pull during winding local hobby shop source music wire cant improved upon material stainless steel spring wire will absorb energy music wire old standby modelers everywhere past 75 years Hobby shop wire diameters 015 020 025 032 047 055 062 possibly 078 Heavier wire beyond scope some what primitive winding procedure Commercial music wire sizes seemingly finite diameter range beginning 005 continuing 001-in increments through 042 continuing 002-in increments 080 tremendous variety choose springs can tailored exact specificationsbut modeling needs far less exacting hobby shop sizes will likely serve smaller sizes mentioned such 015 can used make tension springs apply load ends rigging wires biplanes order remove sag long wires wound mandrel 047 062-in diameter wire anchored mandrel hub means setscrew springs closewound turn wound tight contact 144 Model Aviation preceding turn vise-grip plier held side forces turns tight con tact result spring initial tension built means obtaining maximum stored energy minimum space extra tension available very instant coils begin separate Almost tension-type springs hooks end have initial tension wound during manufacture tensioning rigging wires spring has hook removed direct soldering wire Only other end has hook Heavier wire diameters 047 055 062 used shock-absorbing landing gears telescoping tubes wound com pression springs have evenly-spaced openings between coils adjusting length fin ished spring wind few turns close-wound end End coils can removed using cutoff grinding disc Dremel tool adjust spring length fit space crude methods winding always possible have spring come out exact length needed spring free length controlled closely watching space between coils winding strictly eyeball operation rare spring indeed comes mandrel usable item very first try high rate scrap-making process carefully save scrap springs hope some future Scale model will need spring dimensions present scrap has found its way airplane another trick making compression spring hold vise-grip right angle mandrel centerline two three revolutions swing plier wire off side small amount provide space between coils Near ing end winding swing again 900 position wind several last turns close-wound Producing two springs exactly alike primitive process can frustrating both needed landing gear legs isnt really necessary two within 10% being equal usable Add washers spacers increase length necessary cut off ends mentioned earlier Calculations find opti mum spacing between coils obtain desirable free length spring will help produce spring somewhere ballpark Professional modelmakers industrial plants have trick spacing between coils After first close-wound coils wound mandrel rotation stopped soft copper wire inserted between coils provide spacing requires second hole drilled through mandrel soft wire end spaced portion soft wire cut remainder spring close-wound two three turns landing gear springs desirable soften spring using active turns can wound space available Such spring has slow rate load build-up compressed prevents model being thrown back air hard landing too turns small-diameter wire spring will support models weight too turns large-diameter wire spring reaches its solid length after short deflectionand no longer spring small number turns large-diameter wire provides high load-rate reduces shock absorption because extreme stiffness Stress build-up wire may cause take set spring compressed its solid length coils closed occurs springs free length permanently reduced balance variables usually wire diameter number turns trialand-error calculations inserting values Continued page 146 rAIIJI makers EWWW HEAD LOCK 1-IEADLITE MODEL PRODUCTS CORP PO BOX 100 ALLAMUCHY NEW JERSEY 07820 following formula Load spring rate 0000d4 S D3 N terms have following meanings 11500000 torsional modulus elasticity music wire small d wire diameter large D springs mean diameter its outside diameter minus wire diameter N number active turns including closewound turns spring ends 8 constant formula gives us pounds per inch deflec tion beginning springs free length Adjust free length during winding space between coils keeping mind must fit within strut find load point springs deflection multiply rate determined means formula hy deflection decimal inches get load initial final positions landing-gear travel Remember spring already partially loaded re hound spring used landing gear full size practice Typically airplane weighing 12 lb spring wound 055-in-diameter wire outside diameter 406 having 22 active turns could installed within 500-in GD strut 12 lb distributed six lb leg main gear will produce deflection model rest about 4 dimension somewhat reduced because part models weight supported nose gear tail wheel hut reality ahsorbing landing shocks main gear Wound free length 262 such spring could deflect total 125 absorh landing load 17 lb legor roughly three times models weight spring GD 406 055-in -diameter wire will have inside diame ter 296 Because tendency increase diameter after winding spring wound 25-in-diameter mandrel length wire turn 11 22 turns plus two inactive turns end length wire needed shout 29 Add several inches gripping plier 36-in hohhy shop length wire sufficient spring As indication amount spring-hack wire after winding changing mandrel diameter 28 yields spring GD 43 Bob Dolly Wischer S-221 Lap/tam Peak Rd Delafleld WI 53018 RC Electrics/Kopski Continued page 47 once convenient meaningful way describe motor size early days now m view no longer good approach two ways can illustrated first commercially-made Electric system 05 motor eight 055 Ah 550 mAh cells Astro system gave years service fact still have well-worn motor recall measwing system perform ance specified prop operating power level just about 75 80 watts mind number stock 05 power Now understand new Astro cobalt 02 can operate about same power level Another way see such size ratings dubious value realize contemporary cobalt 05 fully capable handling over twice power first 05 system beyond new Astro FM cobalt 05 goes much farther regard Yet three motors about same physical size weight called OSs So real 05 Considering power-handling abilities Ive just described directly affect well such motors can fly given plane its no wonder would-be Electric fliers experienced ones well get confused Incidentally please note nowhere above did say mentioned motors has less power otherfor motors have power Rather motors have lack ability handle varying power levels Anyway seems clear enough 05 other such designation doesnt mean much anymore So think its time change Ithink its time appropriately describe standardize what meant motor size think modeling industry modeling consumer need standard makes sense wont become outdated changes technology new entries model motor field opinion Electric Aeromodeling Association EAA best-positioned group establish control matter think because EAA official Special Interest Group Electric designated AMA also think its right group because left itself bickering industry will never come up standards Finally Ithink time now Quite naturally Ive got some ideas own subject since Ive just opened up topical area am now going pass along Rememberyou read first Model Avia lion 146 Model Aviation 1 STAIM.ESS STEEL HEAD LOCK glow plug connector strength & long corrosion free life 2FIELD REPLACEABLE 1 2 AH Nicad 3Built FULLY AUTOIIATIC ON/OFF SWITCH prevent short circuits pocket tool box 4Charger LED INDICATOR available
Edition: Model Aviation - 1987/04
Page Numbers: 44, 45, 143, 144, 146
Radio Control Scale Bob Dolly Wischer CABLE SYSTEMS use cables operate elevators rudder now rather common real trick assembling such system matter Scale realism visible external por tions cables should enter through fuselage side proper locations elevator cables cross unusual crossover point should right spot relative cable length other external features requires bit planning possible helpful have some idea cable layout routing prototype aircraft Lacking vital information project line cable photo three-view drawing help determine location internal bellcrank forward ends ca bles connected relatively simple matter install models bellcrank assembly proper location usual method operation full-sized aircraft pivot tube across fuselage bellcrank welded end lever welded near tube center connection cables pushrod control stick model tube could replaced hardwood dowel plywood bellcranks cemented near end pivots drill 062-in diameter hole end dowel insert short lengths 062-in music wire bearings support outer ends wires plywood bearings drilled running fit wires Near dowels center cement another plywood lever connect pushrod servo Details producing cable-operated system thoroughly covered December 1985 column subject being reviewed because problem new Douglas M-2 Mailplane recently came light M-2 has pair cables half elevator Noth ing unusual about visit National Air Space Museum see existing prototype discovered ca bles ran over pulleys stabilizer leading edge - This done give both upper lower cables equal length would maintain tension regardless position through elevator travel Obviously such prominent feature needed Bob liulsinga scratch-built Fairchild 24W 1/scaie L Models power Quadra 50 landing gear welded 4130 steel tubing Finish K&B epoxy over Worldtex took him 20 months build Bob Wisohers new Douglas Maliplane R has four control cables elevatorswhich caused some grief explains column Wingspan 1870 weight 1812 lb Power Enya 120 four-stroke Ace Nylite ii on-board glow ignition cockpit completely detailed has operating rudder barand controi stick Hansa-Brandenburg W-29 1 lathe iatest project Ralph Beck 1/B-scale spans 886 uses 0861 power Ralph used 8 rolls masking tape paint iozenge-pattern camoufiage wings tail surfaces fioats fuselage top H ighiy-detailed construction drawings available Ralph Beck Rt 2 Box 131 Beloit WI 53511 Quarter-scale Aeronca KCA R work Pat Massey its OS Gemini 180 four-stroke twin has dummy cylinders simulate 50-horsepower Continental engine Span 108 weight 1 51/2 lb 44 Model Aviation Homemade music wire springs mandreistheywere wound Top bottom 281 in-dlameter mandrel winds spring 43-in 00 1/4-in-diametersteel rod mandrel 22turn springs tubular shock struts 1 86-in-diameter mandrel used wind springs Douglas Mailpiane shock struts aluminum mandrel 062 047-in music wire pressed ends wind tiny 016-wire springs shown latter used tension rigging wires Douglas Set screws clamp first turn 016 wire duplicated model However pulleys quite free-running presence model introduced four friction points usual servos no trouble overcoming added friction surfaces moved through extremes motion full Up full Down problem became evident however elevators teased around neutral surface would move up example transmitter stick moved very small amount Up direction elevator would completely return neutral control stick releasedtoo much friction sys tem Tightening cables excessively made condition worse Something done maintain controllability near elevator neutral position avoid predictable problems air model would continuously hunting level flight worst condition obviously during land ing Up-elevator applied flare three-point position After raising nose proper wing-angle attack necessary reduce Up-elevator just before wheels touch down depending upon speed speed slightly high elevators cant quickly neu tralized result climb followed stall could produce abrupt landings otherwise known arrival very least damage broken prop worst nose landing gear suffer damage Since flying done small movements control surfaces around neutral rather larger excur sions its important have reliable repeat able neutral solution energetic servos par ticularly good resolution around neu tral Several such servos intended large air craft sailboats available ordinarily require large batteries because high current draw chosen servo Ace Atlas assembled kits price right have 45 in-oz output torque utilize amplifier gives less degree resolution arent small because large diameter 20mm motor supplies high torque current drain isnt excessive regular 550 mAh batteries sufficient vast spaces inside Scale models arent concerned servo size Most important elevators now neutralize completely teased small incremental movements model doesnt gallop over sky search true straight-and-level flight can now have lightweight positive cable system minus nuisance factor poor elevator centering Any us have flown old servos past will remember difficulties attain ing stable flight poor resolution Some Scale models didnt really perform well until having new servos installed years after built Small servos large airplanes led similar troubles variety high-quality ser vos currently hand has made smooth con trollability Scale models reality Spring winding reader asked ex planation technique used making springs special applications area Ace Hardware store has supply springs stockboth compression tension typesand quite often able find suitable springs modeling purposes everyone doesnt have convenient hardware store neighborhood times off-the-shelf springs dont fit application because size load characteristics times like helps know basics making own springs Seven Scale models employed compression springs Continued page 143 1/6 scale fully poseable 1211 action pilots dressed removable fabric flight gear time No painting assembly required WWI & Civilian weigh 6 oz WWII pilot has removable Parachute Mae West weighs 8 oz Add $325 per figure P&H calif res add sales tax Allow 10 days delivery Note Pilots can also fly 1/5 scale ships Send Check money order MGA Enterprises PO Box 626 DeptA Fresno Calif 93709 DRILL MOUNT MASTER Engine hole guide drilling jig Have ever tried accurately lay Out engine mounting holes engine mount Have ever tried drill tap holes have will appreciate DRILL MOUNT MASTER No LAYING OT OF HOLES REQUIRED WHEN USING THE DRILL MOUNT MASTER EXCLUSIVE JTEC TUNE HOLE GUIDE SYSTEM GIVES PERFECTLY MATCHED HOLES EVERY TIME THE DRILLING JIG HOLDS THE ENGINE MOUNT FIRMLY FOR EASY DRILLING AND TAPPING Two SIZES FRONT PRESSURE PLATES TO HOLDOnly ANY ENGINE MOUNT FROM 15 TO 1202995 DRILL MOUNT MASTER IS CAST ALUMINUM MACHINED AND BRIGH POLISHED MADE TO LAST rrol avorloble hobby shop 050th DIRSCT wwrredbate shlprrvenl Check MO VIs MOor COD accepted Add $250 UPS S20O COO 6% saks ta Calif resIdent m9@ pilots m mm April 1987 45 Reverse Knife Edge Flight namely really strange Aerobatic maneuver requiring airplane large lateral area and/or high thrust Lets respond respective Contest Board members feel about proposals cleared Initial Vote hurdle Otherwise have ourselves blame votes go wrong way Nats schedule year will require lot us used late July/early August Nats starting date pay attention July 11 19 dates least two weeks earlier usual Schedule vacation early folks Another impact contests usually Nats tune-ups may too late year Unfortunately may cause some con tests cancelled due direct conflicts because dates proximity Nats know wont able go least contest always look forward attending July last note caption picture Paul Verger Lafayette LA appeared February issue said aileron servo Pauls airplane quit vertical-downward part Square Loop s Have ever seen maneuvers s would real challenge Can see corner end vertical-downward part Tough maneuver Sorry just typo should have s Ron Van Putte 111 Sleepy Oaks Rd Ft Walton Beach FL 32548 landing-gear struts made home Winding springs mandrel really simple operation Anyone access lathe can pro duce springs quantity short time lathe spindle slowed means belt pulleys back gears give speed about revolution per second Slower better possible lathe isnt available mandrel can supported hardwood block clamped vise crank lever fastened end setscrew rotate mandrel manually Lever length about eight inches foot satisfactory winding springs light music wire up 062-in di ameter Drill cross hole through mandrel accept wire size chosen spring Bend music wire end 900 inserted cross hole Whether lathe-wound hand-cranked operation requires two persons example spring about 375-in outside diameter having 062-in music wire 25 turns will use almost three-foot length music wire Tension must applied free end wire force wire closely around mandrel spring wound personthe stronger heavier twostretches wire tightly other operates lathe On-Off switch turns crank have found reliable way grip wires free end plier vise-grip type heavy linemans plier likely slip due tension momentary relaxation operator happens free end wire will whip around arc can easily MORE POWEi1 WITH LESS NOISE four-cycle measuring up expectations read Make engine before Make 60 120 four-stroke less means 1 Quieter glow 2 More mellow sounding four-cycle 3 More usable power both 4 Highest power-to-weight ratio 5 The lowest idle ever 6 Increase mileage up 4 times 7 Runs cooler glow 8 No glowplugs fail 9 Increased reliability 10 Fuel available concentrate Conversion kits available 049 30 cid Schnuerle ported engines Its sim ple just change heads fuel What waiting Dust off two-cycle DIESELIZE Send self-addressed stamped enve lope $100 infoation call 203-877-1670 between 730 pm and 930 pm EST DAVIS DIESEL DEVELOPMENT PO Box 141 Milford CT 06460 leader quiet combustion technology since 1976 April1987143 RC Scale/Wischers Continued page 45 responding advertisers mention read about ModelAviation cause serious damage body parts Always wear eye protection wind heavy wire 062-in diameter example person pulling vise-grip plier must use maximum muscle weight force wire closely around mandrel com pletely wound spring will open slightly larger outside diameter insufficient stretch ing during winding spring-back will exces sive resulting spring will probably fit space allotted Lighter wire needs less pull during winding local hobby shop source music wire cant improved upon material stainless steel spring wire will absorb energy music wire old standby modelers everywhere past 75 years Hobby shop wire diameters 015 020 025 032 047 055 062 possibly 078 Heavier wire beyond scope some what primitive winding procedure Commercial music wire sizes seemingly finite diameter range beginning 005 continuing 001-in increments through 042 continuing 002-in increments 080 tremendous variety choose springs can tailored exact specificationsbut modeling needs far less exacting hobby shop sizes will likely serve smaller sizes mentioned such 015 can used make tension springs apply load ends rigging wires biplanes order remove sag long wires wound mandrel 047 062-in diameter wire anchored mandrel hub means setscrew springs closewound turn wound tight contact 144 Model Aviation preceding turn vise-grip plier held side forces turns tight con tact result spring initial tension built means obtaining maximum stored energy minimum space extra tension available very instant coils begin separate Almost tension-type springs hooks end have initial tension wound during manufacture tensioning rigging wires spring has hook removed direct soldering wire Only other end has hook Heavier wire diameters 047 055 062 used shock-absorbing landing gears telescoping tubes wound com pression springs have evenly-spaced openings between coils adjusting length fin ished spring wind few turns close-wound end End coils can removed using cutoff grinding disc Dremel tool adjust spring length fit space crude methods winding always possible have spring come out exact length needed spring free length controlled closely watching space between coils winding strictly eyeball operation rare spring indeed comes mandrel usable item very first try high rate scrap-making process carefully save scrap springs hope some future Scale model will need spring dimensions present scrap has found its way airplane another trick making compression spring hold vise-grip right angle mandrel centerline two three revolutions swing plier wire off side small amount provide space between coils Near ing end winding swing again 900 position wind several last turns close-wound Producing two springs exactly alike primitive process can frustrating both needed landing gear legs isnt really necessary two within 10% being equal usable Add washers spacers increase length necessary cut off ends mentioned earlier Calculations find opti mum spacing between coils obtain desirable free length spring will help produce spring somewhere ballpark Professional modelmakers industrial plants have trick spacing between coils After first close-wound coils wound mandrel rotation stopped soft copper wire inserted between coils provide spacing requires second hole drilled through mandrel soft wire end spaced portion soft wire cut remainder spring close-wound two three turns landing gear springs desirable soften spring using active turns can wound space available Such spring has slow rate load build-up compressed prevents model being thrown back air hard landing too turns small-diameter wire spring will support models weight too turns large-diameter wire spring reaches its solid length after short deflectionand no longer spring small number turns large-diameter wire provides high load-rate reduces shock absorption because extreme stiffness Stress build-up wire may cause take set spring compressed its solid length coils closed occurs springs free length permanently reduced balance variables usually wire diameter number turns trialand-error calculations inserting values Continued page 146 rAIIJI makers EWWW HEAD LOCK 1-IEADLITE MODEL PRODUCTS CORP PO BOX 100 ALLAMUCHY NEW JERSEY 07820 following formula Load spring rate 0000d4 S D3 N terms have following meanings 11500000 torsional modulus elasticity music wire small d wire diameter large D springs mean diameter its outside diameter minus wire diameter N number active turns including closewound turns spring ends 8 constant formula gives us pounds per inch deflec tion beginning springs free length Adjust free length during winding space between coils keeping mind must fit within strut find load point springs deflection multiply rate determined means formula hy deflection decimal inches get load initial final positions landing-gear travel Remember spring already partially loaded re hound spring used landing gear full size practice Typically airplane weighing 12 lb spring wound 055-in-diameter wire outside diameter 406 having 22 active turns could installed within 500-in GD strut 12 lb distributed six lb leg main gear will produce deflection model rest about 4 dimension somewhat reduced because part models weight supported nose gear tail wheel hut reality ahsorbing landing shocks main gear Wound free length 262 such spring could deflect total 125 absorh landing load 17 lb legor roughly three times models weight spring GD 406 055-in -diameter wire will have inside diame ter 296 Because tendency increase diameter after winding spring wound 25-in-diameter mandrel length wire turn 11 22 turns plus two inactive turns end length wire needed shout 29 Add several inches gripping plier 36-in hohhy shop length wire sufficient spring As indication amount spring-hack wire after winding changing mandrel diameter 28 yields spring GD 43 Bob Dolly Wischer S-221 Lap/tam Peak Rd Delafleld WI 53018 RC Electrics/Kopski Continued page 47 once convenient meaningful way describe motor size early days now m view no longer good approach two ways can illustrated first commercially-made Electric system 05 motor eight 055 Ah 550 mAh cells Astro system gave years service fact still have well-worn motor recall measwing system perform ance specified prop operating power level just about 75 80 watts mind number stock 05 power Now understand new Astro cobalt 02 can operate about same power level Another way see such size ratings dubious value realize contemporary cobalt 05 fully capable handling over twice power first 05 system beyond new Astro FM cobalt 05 goes much farther regard Yet three motors about same physical size weight called OSs So real 05 Considering power-handling abilities Ive just described directly affect well such motors can fly given plane its no wonder would-be Electric fliers experienced ones well get confused Incidentally please note nowhere above did say mentioned motors has less power otherfor motors have power Rather motors have lack ability handle varying power levels Anyway seems clear enough 05 other such designation doesnt mean much anymore So think its time change Ithink its time appropriately describe standardize what meant motor size think modeling industry modeling consumer need standard makes sense wont become outdated changes technology new entries model motor field opinion Electric Aeromodeling Association EAA best-positioned group establish control matter think because EAA official Special Interest Group Electric designated AMA also think its right group because left itself bickering industry will never come up standards Finally Ithink time now Quite naturally Ive got some ideas own subject since Ive just opened up topical area am now going pass along Rememberyou read first Model Avia lion 146 Model Aviation 1 STAIM.ESS STEEL HEAD LOCK glow plug connector strength & long corrosion free life 2FIELD REPLACEABLE 1 2 AH Nicad 3Built FULLY AUTOIIATIC ON/OFF SWITCH prevent short circuits pocket tool box 4Charger LED INDICATOR available
Edition: Model Aviation - 1987/04
Page Numbers: 44, 45, 143, 144, 146
Radio Control Scale Bob Dolly Wischer CABLE SYSTEMS use cables operate elevators rudder now rather common real trick assembling such system matter Scale realism visible external por tions cables should enter through fuselage side proper locations elevator cables cross unusual crossover point should right spot relative cable length other external features requires bit planning possible helpful have some idea cable layout routing prototype aircraft Lacking vital information project line cable photo three-view drawing help determine location internal bellcrank forward ends ca bles connected relatively simple matter install models bellcrank assembly proper location usual method operation full-sized aircraft pivot tube across fuselage bellcrank welded end lever welded near tube center connection cables pushrod control stick model tube could replaced hardwood dowel plywood bellcranks cemented near end pivots drill 062-in diameter hole end dowel insert short lengths 062-in music wire bearings support outer ends wires plywood bearings drilled running fit wires Near dowels center cement another plywood lever connect pushrod servo Details producing cable-operated system thoroughly covered December 1985 column subject being reviewed because problem new Douglas M-2 Mailplane recently came light M-2 has pair cables half elevator Noth ing unusual about visit National Air Space Museum see existing prototype discovered ca bles ran over pulleys stabilizer leading edge - This done give both upper lower cables equal length would maintain tension regardless position through elevator travel Obviously such prominent feature needed Bob liulsinga scratch-built Fairchild 24W 1/scaie L Models power Quadra 50 landing gear welded 4130 steel tubing Finish K&B epoxy over Worldtex took him 20 months build Bob Wisohers new Douglas Maliplane R has four control cables elevatorswhich caused some grief explains column Wingspan 1870 weight 1812 lb Power Enya 120 four-stroke Ace Nylite ii on-board glow ignition cockpit completely detailed has operating rudder barand controi stick Hansa-Brandenburg W-29 1 lathe iatest project Ralph Beck 1/B-scale spans 886 uses 0861 power Ralph used 8 rolls masking tape paint iozenge-pattern camoufiage wings tail surfaces fioats fuselage top H ighiy-detailed construction drawings available Ralph Beck Rt 2 Box 131 Beloit WI 53511 Quarter-scale Aeronca KCA R work Pat Massey its OS Gemini 180 four-stroke twin has dummy cylinders simulate 50-horsepower Continental engine Span 108 weight 1 51/2 lb 44 Model Aviation Homemade music wire springs mandreistheywere wound Top bottom 281 in-dlameter mandrel winds spring 43-in 00 1/4-in-diametersteel rod mandrel 22turn springs tubular shock struts 1 86-in-diameter mandrel used wind springs Douglas Mailpiane shock struts aluminum mandrel 062 047-in music wire pressed ends wind tiny 016-wire springs shown latter used tension rigging wires Douglas Set screws clamp first turn 016 wire duplicated model However pulleys quite free-running presence model introduced four friction points usual servos no trouble overcoming added friction surfaces moved through extremes motion full Up full Down problem became evident however elevators teased around neutral surface would move up example transmitter stick moved very small amount Up direction elevator would completely return neutral control stick releasedtoo much friction sys tem Tightening cables excessively made condition worse Something done maintain controllability near elevator neutral position avoid predictable problems air model would continuously hunting level flight worst condition obviously during land ing Up-elevator applied flare three-point position After raising nose proper wing-angle attack necessary reduce Up-elevator just before wheels touch down depending upon speed speed slightly high elevators cant quickly neu tralized result climb followed stall could produce abrupt landings otherwise known arrival very least damage broken prop worst nose landing gear suffer damage Since flying done small movements control surfaces around neutral rather larger excur sions its important have reliable repeat able neutral solution energetic servos par ticularly good resolution around neu tral Several such servos intended large air craft sailboats available ordinarily require large batteries because high current draw chosen servo Ace Atlas assembled kits price right have 45 in-oz output torque utilize amplifier gives less degree resolution arent small because large diameter 20mm motor supplies high torque current drain isnt excessive regular 550 mAh batteries sufficient vast spaces inside Scale models arent concerned servo size Most important elevators now neutralize completely teased small incremental movements model doesnt gallop over sky search true straight-and-level flight can now have lightweight positive cable system minus nuisance factor poor elevator centering Any us have flown old servos past will remember difficulties attain ing stable flight poor resolution Some Scale models didnt really perform well until having new servos installed years after built Small servos large airplanes led similar troubles variety high-quality ser vos currently hand has made smooth con trollability Scale models reality Spring winding reader asked ex planation technique used making springs special applications area Ace Hardware store has supply springs stockboth compression tension typesand quite often able find suitable springs modeling purposes everyone doesnt have convenient hardware store neighborhood times off-the-shelf springs dont fit application because size load characteristics times like helps know basics making own springs Seven Scale models employed compression springs Continued page 143 1/6 scale fully poseable 1211 action pilots dressed removable fabric flight gear time No painting assembly required WWI & Civilian weigh 6 oz WWII pilot has removable Parachute Mae West weighs 8 oz Add $325 per figure P&H calif res add sales tax Allow 10 days delivery Note Pilots can also fly 1/5 scale ships Send Check money order MGA Enterprises PO Box 626 DeptA Fresno Calif 93709 DRILL MOUNT MASTER Engine hole guide drilling jig Have ever tried accurately lay Out engine mounting holes engine mount Have ever tried drill tap holes have will appreciate DRILL MOUNT MASTER No LAYING OT OF HOLES REQUIRED WHEN USING THE DRILL MOUNT MASTER EXCLUSIVE JTEC TUNE HOLE GUIDE SYSTEM GIVES PERFECTLY MATCHED HOLES EVERY TIME THE DRILLING JIG HOLDS THE ENGINE MOUNT FIRMLY FOR EASY DRILLING AND TAPPING Two SIZES FRONT PRESSURE PLATES TO HOLDOnly ANY ENGINE MOUNT FROM 15 TO 1202995 DRILL MOUNT MASTER IS CAST ALUMINUM MACHINED AND BRIGH POLISHED MADE TO LAST rrol avorloble hobby shop 050th DIRSCT wwrredbate shlprrvenl Check MO VIs MOor COD accepted Add $250 UPS S20O COO 6% saks ta Calif resIdent m9@ pilots m mm April 1987 45 Reverse Knife Edge Flight namely really strange Aerobatic maneuver requiring airplane large lateral area and/or high thrust Lets respond respective Contest Board members feel about proposals cleared Initial Vote hurdle Otherwise have ourselves blame votes go wrong way Nats schedule year will require lot us used late July/early August Nats starting date pay attention July 11 19 dates least two weeks earlier usual Schedule vacation early folks Another impact contests usually Nats tune-ups may too late year Unfortunately may cause some con tests cancelled due direct conflicts because dates proximity Nats know wont able go least contest always look forward attending July last note caption picture Paul Verger Lafayette LA appeared February issue said aileron servo Pauls airplane quit vertical-downward part Square Loop s Have ever seen maneuvers s would real challenge Can see corner end vertical-downward part Tough maneuver Sorry just typo should have s Ron Van Putte 111 Sleepy Oaks Rd Ft Walton Beach FL 32548 landing-gear struts made home Winding springs mandrel really simple operation Anyone access lathe can pro duce springs quantity short time lathe spindle slowed means belt pulleys back gears give speed about revolution per second Slower better possible lathe isnt available mandrel can supported hardwood block clamped vise crank lever fastened end setscrew rotate mandrel manually Lever length about eight inches foot satisfactory winding springs light music wire up 062-in di ameter Drill cross hole through mandrel accept wire size chosen spring Bend music wire end 900 inserted cross hole Whether lathe-wound hand-cranked operation requires two persons example spring about 375-in outside diameter having 062-in music wire 25 turns will use almost three-foot length music wire Tension must applied free end wire force wire closely around mandrel spring wound personthe stronger heavier twostretches wire tightly other operates lathe On-Off switch turns crank have found reliable way grip wires free end plier vise-grip type heavy linemans plier likely slip due tension momentary relaxation operator happens free end wire will whip around arc can easily MORE POWEi1 WITH LESS NOISE four-cycle measuring up expectations read Make engine before Make 60 120 four-stroke less means 1 Quieter glow 2 More mellow sounding four-cycle 3 More usable power both 4 Highest power-to-weight ratio 5 The lowest idle ever 6 Increase mileage up 4 times 7 Runs cooler glow 8 No glowplugs fail 9 Increased reliability 10 Fuel available concentrate Conversion kits available 049 30 cid Schnuerle ported engines Its sim ple just change heads fuel What waiting Dust off two-cycle DIESELIZE Send self-addressed stamped enve lope $100 infoation call 203-877-1670 between 730 pm and 930 pm EST DAVIS DIESEL DEVELOPMENT PO Box 141 Milford CT 06460 leader quiet combustion technology since 1976 April1987143 RC Scale/Wischers Continued page 45 responding advertisers mention read about ModelAviation cause serious damage body parts Always wear eye protection wind heavy wire 062-in diameter example person pulling vise-grip plier must use maximum muscle weight force wire closely around mandrel com pletely wound spring will open slightly larger outside diameter insufficient stretch ing during winding spring-back will exces sive resulting spring will probably fit space allotted Lighter wire needs less pull during winding local hobby shop source music wire cant improved upon material stainless steel spring wire will absorb energy music wire old standby modelers everywhere past 75 years Hobby shop wire diameters 015 020 025 032 047 055 062 possibly 078 Heavier wire beyond scope some what primitive winding procedure Commercial music wire sizes seemingly finite diameter range beginning 005 continuing 001-in increments through 042 continuing 002-in increments 080 tremendous variety choose springs can tailored exact specificationsbut modeling needs far less exacting hobby shop sizes will likely serve smaller sizes mentioned such 015 can used make tension springs apply load ends rigging wires biplanes order remove sag long wires wound mandrel 047 062-in diameter wire anchored mandrel hub means setscrew springs closewound turn wound tight contact 144 Model Aviation preceding turn vise-grip plier held side forces turns tight con tact result spring initial tension built means obtaining maximum stored energy minimum space extra tension available very instant coils begin separate Almost tension-type springs hooks end have initial tension wound during manufacture tensioning rigging wires spring has hook removed direct soldering wire Only other end has hook Heavier wire diameters 047 055 062 used shock-absorbing landing gears telescoping tubes wound com pression springs have evenly-spaced openings between coils adjusting length fin ished spring wind few turns close-wound end End coils can removed using cutoff grinding disc Dremel tool adjust spring length fit space crude methods winding always possible have spring come out exact length needed spring free length controlled closely watching space between coils winding strictly eyeball operation rare spring indeed comes mandrel usable item very first try high rate scrap-making process carefully save scrap springs hope some future Scale model will need spring dimensions present scrap has found its way airplane another trick making compression spring hold vise-grip right angle mandrel centerline two three revolutions swing plier wire off side small amount provide space between coils Near ing end winding swing again 900 position wind several last turns close-wound Producing two springs exactly alike primitive process can frustrating both needed landing gear legs isnt really necessary two within 10% being equal usable Add washers spacers increase length necessary cut off ends mentioned earlier Calculations find opti mum spacing between coils obtain desirable free length spring will help produce spring somewhere ballpark Professional modelmakers industrial plants have trick spacing between coils After first close-wound coils wound mandrel rotation stopped soft copper wire inserted between coils provide spacing requires second hole drilled through mandrel soft wire end spaced portion soft wire cut remainder spring close-wound two three turns landing gear springs desirable soften spring using active turns can wound space available Such spring has slow rate load build-up compressed prevents model being thrown back air hard landing too turns small-diameter wire spring will support models weight too turns large-diameter wire spring reaches its solid length after short deflectionand no longer spring small number turns large-diameter wire provides high load-rate reduces shock absorption because extreme stiffness Stress build-up wire may cause take set spring compressed its solid length coils closed occurs springs free length permanently reduced balance variables usually wire diameter number turns trialand-error calculations inserting values Continued page 146 rAIIJI makers EWWW HEAD LOCK 1-IEADLITE MODEL PRODUCTS CORP PO BOX 100 ALLAMUCHY NEW JERSEY 07820 following formula Load spring rate 0000d4 S D3 N terms have following meanings 11500000 torsional modulus elasticity music wire small d wire diameter large D springs mean diameter its outside diameter minus wire diameter N number active turns including closewound turns spring ends 8 constant formula gives us pounds per inch deflec tion beginning springs free length Adjust free length during winding space between coils keeping mind must fit within strut find load point springs deflection multiply rate determined means formula hy deflection decimal inches get load initial final positions landing-gear travel Remember spring already partially loaded re hound spring used landing gear full size practice Typically airplane weighing 12 lb spring wound 055-in-diameter wire outside diameter 406 having 22 active turns could installed within 500-in GD strut 12 lb distributed six lb leg main gear will produce deflection model rest about 4 dimension somewhat reduced because part models weight supported nose gear tail wheel hut reality ahsorbing landing shocks main gear Wound free length 262 such spring could deflect total 125 absorh landing load 17 lb legor roughly three times models weight spring GD 406 055-in -diameter wire will have inside diame ter 296 Because tendency increase diameter after winding spring wound 25-in-diameter mandrel length wire turn 11 22 turns plus two inactive turns end length wire needed shout 29 Add several inches gripping plier 36-in hohhy shop length wire sufficient spring As indication amount spring-hack wire after winding changing mandrel diameter 28 yields spring GD 43 Bob Dolly Wischer S-221 Lap/tam Peak Rd Delafleld WI 53018 RC Electrics/Kopski Continued page 47 once convenient meaningful way describe motor size early days now m view no longer good approach two ways can illustrated first commercially-made Electric system 05 motor eight 055 Ah 550 mAh cells Astro system gave years service fact still have well-worn motor recall measwing system perform ance specified prop operating power level just about 75 80 watts mind number stock 05 power Now understand new Astro cobalt 02 can operate about same power level Another way see such size ratings dubious value realize contemporary cobalt 05 fully capable handling over twice power first 05 system beyond new Astro FM cobalt 05 goes much farther regard Yet three motors about same physical size weight called OSs So real 05 Considering power-handling abilities Ive just described directly affect well such motors can fly given plane its no wonder would-be Electric fliers experienced ones well get confused Incidentally please note nowhere above did say mentioned motors has less power otherfor motors have power Rather motors have lack ability handle varying power levels Anyway seems clear enough 05 other such designation doesnt mean much anymore So think its time change Ithink its time appropriately describe standardize what meant motor size think modeling industry modeling consumer need standard makes sense wont become outdated changes technology new entries model motor field opinion Electric Aeromodeling Association EAA best-positioned group establish control matter think because EAA official Special Interest Group Electric designated AMA also think its right group because left itself bickering industry will never come up standards Finally Ithink time now Quite naturally Ive got some ideas own subject since Ive just opened up topical area am now going pass along Rememberyou read first Model Avia lion 146 Model Aviation 1 STAIM.ESS STEEL HEAD LOCK glow plug connector strength & long corrosion free life 2FIELD REPLACEABLE 1 2 AH Nicad 3Built FULLY AUTOIIATIC ON/OFF SWITCH prevent short circuits pocket tool box 4Charger LED INDICATOR available
Edition: Model Aviation - 1987/04
Page Numbers: 44, 45, 143, 144, 146
Radio Control Scale Bob Dolly Wischer CABLE SYSTEMS use cables operate elevators rudder now rather common real trick assembling such system matter Scale realism visible external por tions cables should enter through fuselage side proper locations elevator cables cross unusual crossover point should right spot relative cable length other external features requires bit planning possible helpful have some idea cable layout routing prototype aircraft Lacking vital information project line cable photo three-view drawing help determine location internal bellcrank forward ends ca bles connected relatively simple matter install models bellcrank assembly proper location usual method operation full-sized aircraft pivot tube across fuselage bellcrank welded end lever welded near tube center connection cables pushrod control stick model tube could replaced hardwood dowel plywood bellcranks cemented near end pivots drill 062-in diameter hole end dowel insert short lengths 062-in music wire bearings support outer ends wires plywood bearings drilled running fit wires Near dowels center cement another plywood lever connect pushrod servo Details producing cable-operated system thoroughly covered December 1985 column subject being reviewed because problem new Douglas M-2 Mailplane recently came light M-2 has pair cables half elevator Noth ing unusual about visit National Air Space Museum see existing prototype discovered ca bles ran over pulleys stabilizer leading edge - This done give both upper lower cables equal length would maintain tension regardless position through elevator travel Obviously such prominent feature needed Bob liulsinga scratch-built Fairchild 24W 1/scaie L Models power Quadra 50 landing gear welded 4130 steel tubing Finish K&B epoxy over Worldtex took him 20 months build Bob Wisohers new Douglas Maliplane R has four control cables elevatorswhich caused some grief explains column Wingspan 1870 weight 1812 lb Power Enya 120 four-stroke Ace Nylite ii on-board glow ignition cockpit completely detailed has operating rudder barand controi stick Hansa-Brandenburg W-29 1 lathe iatest project Ralph Beck 1/B-scale spans 886 uses 0861 power Ralph used 8 rolls masking tape paint iozenge-pattern camoufiage wings tail surfaces fioats fuselage top H ighiy-detailed construction drawings available Ralph Beck Rt 2 Box 131 Beloit WI 53511 Quarter-scale Aeronca KCA R work Pat Massey its OS Gemini 180 four-stroke twin has dummy cylinders simulate 50-horsepower Continental engine Span 108 weight 1 51/2 lb 44 Model Aviation Homemade music wire springs mandreistheywere wound Top bottom 281 in-dlameter mandrel winds spring 43-in 00 1/4-in-diametersteel rod mandrel 22turn springs tubular shock struts 1 86-in-diameter mandrel used wind springs Douglas Mailpiane shock struts aluminum mandrel 062 047-in music wire pressed ends wind tiny 016-wire springs shown latter used tension rigging wires Douglas Set screws clamp first turn 016 wire duplicated model However pulleys quite free-running presence model introduced four friction points usual servos no trouble overcoming added friction surfaces moved through extremes motion full Up full Down problem became evident however elevators teased around neutral surface would move up example transmitter stick moved very small amount Up direction elevator would completely return neutral control stick releasedtoo much friction sys tem Tightening cables excessively made condition worse Something done maintain controllability near elevator neutral position avoid predictable problems air model would continuously hunting level flight worst condition obviously during land ing Up-elevator applied flare three-point position After raising nose proper wing-angle attack necessary reduce Up-elevator just before wheels touch down depending upon speed speed slightly high elevators cant quickly neu tralized result climb followed stall could produce abrupt landings otherwise known arrival very least damage broken prop worst nose landing gear suffer damage Since flying done small movements control surfaces around neutral rather larger excur sions its important have reliable repeat able neutral solution energetic servos par ticularly good resolution around neu tral Several such servos intended large air craft sailboats available ordinarily require large batteries because high current draw chosen servo Ace Atlas assembled kits price right have 45 in-oz output torque utilize amplifier gives less degree resolution arent small because large diameter 20mm motor supplies high torque current drain isnt excessive regular 550 mAh batteries sufficient vast spaces inside Scale models arent concerned servo size Most important elevators now neutralize completely teased small incremental movements model doesnt gallop over sky search true straight-and-level flight can now have lightweight positive cable system minus nuisance factor poor elevator centering Any us have flown old servos past will remember difficulties attain ing stable flight poor resolution Some Scale models didnt really perform well until having new servos installed years after built Small servos large airplanes led similar troubles variety high-quality ser vos currently hand has made smooth con trollability Scale models reality Spring winding reader asked ex planation technique used making springs special applications area Ace Hardware store has supply springs stockboth compression tension typesand quite often able find suitable springs modeling purposes everyone doesnt have convenient hardware store neighborhood times off-the-shelf springs dont fit application because size load characteristics times like helps know basics making own springs Seven Scale models employed compression springs Continued page 143 1/6 scale fully poseable 1211 action pilots dressed removable fabric flight gear time No painting assembly required WWI & Civilian weigh 6 oz WWII pilot has removable Parachute Mae West weighs 8 oz Add $325 per figure P&H calif res add sales tax Allow 10 days delivery Note Pilots can also fly 1/5 scale ships Send Check money order MGA Enterprises PO Box 626 DeptA Fresno Calif 93709 DRILL MOUNT MASTER Engine hole guide drilling jig Have ever tried accurately lay Out engine mounting holes engine mount Have ever tried drill tap holes have will appreciate DRILL MOUNT MASTER No LAYING OT OF HOLES REQUIRED WHEN USING THE DRILL MOUNT MASTER EXCLUSIVE JTEC TUNE HOLE GUIDE SYSTEM GIVES PERFECTLY MATCHED HOLES EVERY TIME THE DRILLING JIG HOLDS THE ENGINE MOUNT FIRMLY FOR EASY DRILLING AND TAPPING Two SIZES FRONT PRESSURE PLATES TO HOLDOnly ANY ENGINE MOUNT FROM 15 TO 1202995 DRILL MOUNT MASTER IS CAST ALUMINUM MACHINED AND BRIGH POLISHED MADE TO LAST rrol avorloble hobby shop 050th DIRSCT wwrredbate shlprrvenl Check MO VIs MOor COD accepted Add $250 UPS S20O COO 6% saks ta Calif resIdent m9@ pilots m mm April 1987 45 Reverse Knife Edge Flight namely really strange Aerobatic maneuver requiring airplane large lateral area and/or high thrust Lets respond respective Contest Board members feel about proposals cleared Initial Vote hurdle Otherwise have ourselves blame votes go wrong way Nats schedule year will require lot us used late July/early August Nats starting date pay attention July 11 19 dates least two weeks earlier usual Schedule vacation early folks Another impact contests usually Nats tune-ups may too late year Unfortunately may cause some con tests cancelled due direct conflicts because dates proximity Nats know wont able go least contest always look forward attending July last note caption picture Paul Verger Lafayette LA appeared February issue said aileron servo Pauls airplane quit vertical-downward part Square Loop s Have ever seen maneuvers s would real challenge Can see corner end vertical-downward part Tough maneuver Sorry just typo should have s Ron Van Putte 111 Sleepy Oaks Rd Ft Walton Beach FL 32548 landing-gear struts made home Winding springs mandrel really simple operation Anyone access lathe can pro duce springs quantity short time lathe spindle slowed means belt pulleys back gears give speed about revolution per second Slower better possible lathe isnt available mandrel can supported hardwood block clamped vise crank lever fastened end setscrew rotate mandrel manually Lever length about eight inches foot satisfactory winding springs light music wire up 062-in di ameter Drill cross hole through mandrel accept wire size chosen spring Bend music wire end 900 inserted cross hole Whether lathe-wound hand-cranked operation requires two persons example spring about 375-in outside diameter having 062-in music wire 25 turns will use almost three-foot length music wire Tension must applied free end wire force wire closely around mandrel spring wound personthe stronger heavier twostretches wire tightly other operates lathe On-Off switch turns crank have found reliable way grip wires free end plier vise-grip type heavy linemans plier likely slip due tension momentary relaxation operator happens free end wire will whip around arc can easily MORE POWEi1 WITH LESS NOISE four-cycle measuring up expectations read Make engine before Make 60 120 four-stroke less means 1 Quieter glow 2 More mellow sounding four-cycle 3 More usable power both 4 Highest power-to-weight ratio 5 The lowest idle ever 6 Increase mileage up 4 times 7 Runs cooler glow 8 No glowplugs fail 9 Increased reliability 10 Fuel available concentrate Conversion kits available 049 30 cid Schnuerle ported engines Its sim ple just change heads fuel What waiting Dust off two-cycle DIESELIZE Send self-addressed stamped enve lope $100 infoation call 203-877-1670 between 730 pm and 930 pm EST DAVIS DIESEL DEVELOPMENT PO Box 141 Milford CT 06460 leader quiet combustion technology since 1976 April1987143 RC Scale/Wischers Continued page 45 responding advertisers mention read about ModelAviation cause serious damage body parts Always wear eye protection wind heavy wire 062-in diameter example person pulling vise-grip plier must use maximum muscle weight force wire closely around mandrel com pletely wound spring will open slightly larger outside diameter insufficient stretch ing during winding spring-back will exces sive resulting spring will probably fit space allotted Lighter wire needs less pull during winding local hobby shop source music wire cant improved upon material stainless steel spring wire will absorb energy music wire old standby modelers everywhere past 75 years Hobby shop wire diameters 015 020 025 032 047 055 062 possibly 078 Heavier wire beyond scope some what primitive winding procedure Commercial music wire sizes seemingly finite diameter range beginning 005 continuing 001-in increments through 042 continuing 002-in increments 080 tremendous variety choose springs can tailored exact specificationsbut modeling needs far less exacting hobby shop sizes will likely serve smaller sizes mentioned such 015 can used make tension springs apply load ends rigging wires biplanes order remove sag long wires wound mandrel 047 062-in diameter wire anchored mandrel hub means setscrew springs closewound turn wound tight contact 144 Model Aviation preceding turn vise-grip plier held side forces turns tight con tact result spring initial tension built means obtaining maximum stored energy minimum space extra tension available very instant coils begin separate Almost tension-type springs hooks end have initial tension wound during manufacture tensioning rigging wires spring has hook removed direct soldering wire Only other end has hook Heavier wire diameters 047 055 062 used shock-absorbing landing gears telescoping tubes wound com pression springs have evenly-spaced openings between coils adjusting length fin ished spring wind few turns close-wound end End coils can removed using cutoff grinding disc Dremel tool adjust spring length fit space crude methods winding always possible have spring come out exact length needed spring free length controlled closely watching space between coils winding strictly eyeball operation rare spring indeed comes mandrel usable item very first try high rate scrap-making process carefully save scrap springs hope some future Scale model will need spring dimensions present scrap has found its way airplane another trick making compression spring hold vise-grip right angle mandrel centerline two three revolutions swing plier wire off side small amount provide space between coils Near ing end winding swing again 900 position wind several last turns close-wound Producing two springs exactly alike primitive process can frustrating both needed landing gear legs isnt really necessary two within 10% being equal usable Add washers spacers increase length necessary cut off ends mentioned earlier Calculations find opti mum spacing between coils obtain desirable free length spring will help produce spring somewhere ballpark Professional modelmakers industrial plants have trick spacing between coils After first close-wound coils wound mandrel rotation stopped soft copper wire inserted between coils provide spacing requires second hole drilled through mandrel soft wire end spaced portion soft wire cut remainder spring close-wound two three turns landing gear springs desirable soften spring using active turns can wound space available Such spring has slow rate load build-up compressed prevents model being thrown back air hard landing too turns small-diameter wire spring will support models weight too turns large-diameter wire spring reaches its solid length after short deflectionand no longer spring small number turns large-diameter wire provides high load-rate reduces shock absorption because extreme stiffness Stress build-up wire may cause take set spring compressed its solid length coils closed occurs springs free length permanently reduced balance variables usually wire diameter number turns trialand-error calculations inserting values Continued page 146 rAIIJI makers EWWW HEAD LOCK 1-IEADLITE MODEL PRODUCTS CORP PO BOX 100 ALLAMUCHY NEW JERSEY 07820 following formula Load spring rate 0000d4 S D3 N terms have following meanings 11500000 torsional modulus elasticity music wire small d wire diameter large D springs mean diameter its outside diameter minus wire diameter N number active turns including closewound turns spring ends 8 constant formula gives us pounds per inch deflec tion beginning springs free length Adjust free length during winding space between coils keeping mind must fit within strut find load point springs deflection multiply rate determined means formula hy deflection decimal inches get load initial final positions landing-gear travel Remember spring already partially loaded re hound spring used landing gear full size practice Typically airplane weighing 12 lb spring wound 055-in-diameter wire outside diameter 406 having 22 active turns could installed within 500-in GD strut 12 lb distributed six lb leg main gear will produce deflection model rest about 4 dimension somewhat reduced because part models weight supported nose gear tail wheel hut reality ahsorbing landing shocks main gear Wound free length 262 such spring could deflect total 125 absorh landing load 17 lb legor roughly three times models weight spring GD 406 055-in -diameter wire will have inside diame ter 296 Because tendency increase diameter after winding spring wound 25-in-diameter mandrel length wire turn 11 22 turns plus two inactive turns end length wire needed shout 29 Add several inches gripping plier 36-in hohhy shop length wire sufficient spring As indication amount spring-hack wire after winding changing mandrel diameter 28 yields spring GD 43 Bob Dolly Wischer S-221 Lap/tam Peak Rd Delafleld WI 53018 RC Electrics/Kopski Continued page 47 once convenient meaningful way describe motor size early days now m view no longer good approach two ways can illustrated first commercially-made Electric system 05 motor eight 055 Ah 550 mAh cells Astro system gave years service fact still have well-worn motor recall measwing system perform ance specified prop operating power level just about 75 80 watts mind number stock 05 power Now understand new Astro cobalt 02 can operate about same power level Another way see such size ratings dubious value realize contemporary cobalt 05 fully capable handling over twice power first 05 system beyond new Astro FM cobalt 05 goes much farther regard Yet three motors about same physical size weight called OSs So real 05 Considering power-handling abilities Ive just described directly affect well such motors can fly given plane its no wonder would-be Electric fliers experienced ones well get confused Incidentally please note nowhere above did say mentioned motors has less power otherfor motors have power Rather motors have lack ability handle varying power levels Anyway seems clear enough 05 other such designation doesnt mean much anymore So think its time change Ithink its time appropriately describe standardize what meant motor size think modeling industry modeling consumer need standard makes sense wont become outdated changes technology new entries model motor field opinion Electric Aeromodeling Association EAA best-positioned group establish control matter think because EAA official Special Interest Group Electric designated AMA also think its right group because left itself bickering industry will never come up standards Finally Ithink time now Quite naturally Ive got some ideas own subject since Ive just opened up topical area am now going pass along Rememberyou read first Model Avia lion 146 Model Aviation 1 STAIM.ESS STEEL HEAD LOCK glow plug connector strength & long corrosion free life 2FIELD REPLACEABLE 1 2 AH Nicad 3Built FULLY AUTOIIATIC ON/OFF SWITCH prevent short circuits pocket tool box 4Charger LED INDICATOR available
Edition: Model Aviation - 1987/04
Page Numbers: 44, 45, 143, 144, 146
Radio Control Scale Bob Dolly Wischer CABLE SYSTEMS use cables operate elevators rudder now rather common real trick assembling such system matter Scale realism visible external por tions cables should enter through fuselage side proper locations elevator cables cross unusual crossover point should right spot relative cable length other external features requires bit planning possible helpful have some idea cable layout routing prototype aircraft Lacking vital information project line cable photo three-view drawing help determine location internal bellcrank forward ends ca bles connected relatively simple matter install models bellcrank assembly proper location usual method operation full-sized aircraft pivot tube across fuselage bellcrank welded end lever welded near tube center connection cables pushrod control stick model tube could replaced hardwood dowel plywood bellcranks cemented near end pivots drill 062-in diameter hole end dowel insert short lengths 062-in music wire bearings support outer ends wires plywood bearings drilled running fit wires Near dowels center cement another plywood lever connect pushrod servo Details producing cable-operated system thoroughly covered December 1985 column subject being reviewed because problem new Douglas M-2 Mailplane recently came light M-2 has pair cables half elevator Noth ing unusual about visit National Air Space Museum see existing prototype discovered ca bles ran over pulleys stabilizer leading edge - This done give both upper lower cables equal length would maintain tension regardless position through elevator travel Obviously such prominent feature needed Bob liulsinga scratch-built Fairchild 24W 1/scaie L Models power Quadra 50 landing gear welded 4130 steel tubing Finish K&B epoxy over Worldtex took him 20 months build Bob Wisohers new Douglas Maliplane R has four control cables elevatorswhich caused some grief explains column Wingspan 1870 weight 1812 lb Power Enya 120 four-stroke Ace Nylite ii on-board glow ignition cockpit completely detailed has operating rudder barand controi stick Hansa-Brandenburg W-29 1 lathe iatest project Ralph Beck 1/B-scale spans 886 uses 0861 power Ralph used 8 rolls masking tape paint iozenge-pattern camoufiage wings tail surfaces fioats fuselage top H ighiy-detailed construction drawings available Ralph Beck Rt 2 Box 131 Beloit WI 53511 Quarter-scale Aeronca KCA R work Pat Massey its OS Gemini 180 four-stroke twin has dummy cylinders simulate 50-horsepower Continental engine Span 108 weight 1 51/2 lb 44 Model Aviation Homemade music wire springs mandreistheywere wound Top bottom 281 in-dlameter mandrel winds spring 43-in 00 1/4-in-diametersteel rod mandrel 22turn springs tubular shock struts 1 86-in-diameter mandrel used wind springs Douglas Mailpiane shock struts aluminum mandrel 062 047-in music wire pressed ends wind tiny 016-wire springs shown latter used tension rigging wires Douglas Set screws clamp first turn 016 wire duplicated model However pulleys quite free-running presence model introduced four friction points usual servos no trouble overcoming added friction surfaces moved through extremes motion full Up full Down problem became evident however elevators teased around neutral surface would move up example transmitter stick moved very small amount Up direction elevator would completely return neutral control stick releasedtoo much friction sys tem Tightening cables excessively made condition worse Something done maintain controllability near elevator neutral position avoid predictable problems air model would continuously hunting level flight worst condition obviously during land ing Up-elevator applied flare three-point position After raising nose proper wing-angle attack necessary reduce Up-elevator just before wheels touch down depending upon speed speed slightly high elevators cant quickly neu tralized result climb followed stall could produce abrupt landings otherwise known arrival very least damage broken prop worst nose landing gear suffer damage Since flying done small movements control surfaces around neutral rather larger excur sions its important have reliable repeat able neutral solution energetic servos par ticularly good resolution around neu tral Several such servos intended large air craft sailboats available ordinarily require large batteries because high current draw chosen servo Ace Atlas assembled kits price right have 45 in-oz output torque utilize amplifier gives less degree resolution arent small because large diameter 20mm motor supplies high torque current drain isnt excessive regular 550 mAh batteries sufficient vast spaces inside Scale models arent concerned servo size Most important elevators now neutralize completely teased small incremental movements model doesnt gallop over sky search true straight-and-level flight can now have lightweight positive cable system minus nuisance factor poor elevator centering Any us have flown old servos past will remember difficulties attain ing stable flight poor resolution Some Scale models didnt really perform well until having new servos installed years after built Small servos large airplanes led similar troubles variety high-quality ser vos currently hand has made smooth con trollability Scale models reality Spring winding reader asked ex planation technique used making springs special applications area Ace Hardware store has supply springs stockboth compression tension typesand quite often able find suitable springs modeling purposes everyone doesnt have convenient hardware store neighborhood times off-the-shelf springs dont fit application because size load characteristics times like helps know basics making own springs Seven Scale models employed compression springs Continued page 143 1/6 scale fully poseable 1211 action pilots dressed removable fabric flight gear time No painting assembly required WWI & Civilian weigh 6 oz WWII pilot has removable Parachute Mae West weighs 8 oz Add $325 per figure P&H calif res add sales tax Allow 10 days delivery Note Pilots can also fly 1/5 scale ships Send Check money order MGA Enterprises PO Box 626 DeptA Fresno Calif 93709 DRILL MOUNT MASTER Engine hole guide drilling jig Have ever tried accurately lay Out engine mounting holes engine mount Have ever tried drill tap holes have will appreciate DRILL MOUNT MASTER No LAYING OT OF HOLES REQUIRED WHEN USING THE DRILL MOUNT MASTER EXCLUSIVE JTEC TUNE HOLE GUIDE SYSTEM GIVES PERFECTLY MATCHED HOLES EVERY TIME THE DRILLING JIG HOLDS THE ENGINE MOUNT FIRMLY FOR EASY DRILLING AND TAPPING Two SIZES FRONT PRESSURE PLATES TO HOLDOnly ANY ENGINE MOUNT FROM 15 TO 1202995 DRILL MOUNT MASTER IS CAST ALUMINUM MACHINED AND BRIGH POLISHED MADE TO LAST rrol avorloble hobby shop 050th DIRSCT wwrredbate shlprrvenl Check MO VIs MOor COD accepted Add $250 UPS S20O COO 6% saks ta Calif resIdent m9@ pilots m mm April 1987 45 Reverse Knife Edge Flight namely really strange Aerobatic maneuver requiring airplane large lateral area and/or high thrust Lets respond respective Contest Board members feel about proposals cleared Initial Vote hurdle Otherwise have ourselves blame votes go wrong way Nats schedule year will require lot us used late July/early August Nats starting date pay attention July 11 19 dates least two weeks earlier usual Schedule vacation early folks Another impact contests usually Nats tune-ups may too late year Unfortunately may cause some con tests cancelled due direct conflicts because dates proximity Nats know wont able go least contest always look forward attending July last note caption picture Paul Verger Lafayette LA appeared February issue said aileron servo Pauls airplane quit vertical-downward part Square Loop s Have ever seen maneuvers s would real challenge Can see corner end vertical-downward part Tough maneuver Sorry just typo should have s Ron Van Putte 111 Sleepy Oaks Rd Ft Walton Beach FL 32548 landing-gear struts made home Winding springs mandrel really simple operation Anyone access lathe can pro duce springs quantity short time lathe spindle slowed means belt pulleys back gears give speed about revolution per second Slower better possible lathe isnt available mandrel can supported hardwood block clamped vise crank lever fastened end setscrew rotate mandrel manually Lever length about eight inches foot satisfactory winding springs light music wire up 062-in di ameter Drill cross hole through mandrel accept wire size chosen spring Bend music wire end 900 inserted cross hole Whether lathe-wound hand-cranked operation requires two persons example spring about 375-in outside diameter having 062-in music wire 25 turns will use almost three-foot length music wire Tension must applied free end wire force wire closely around mandrel spring wound personthe stronger heavier twostretches wire tightly other operates lathe On-Off switch turns crank have found reliable way grip wires free end plier vise-grip type heavy linemans plier likely slip due tension momentary relaxation operator happens free end wire will whip around arc can easily MORE POWEi1 WITH LESS NOISE four-cycle measuring up expectations read Make engine before Make 60 120 four-stroke less means 1 Quieter glow 2 More mellow sounding four-cycle 3 More usable power both 4 Highest power-to-weight ratio 5 The lowest idle ever 6 Increase mileage up 4 times 7 Runs cooler glow 8 No glowplugs fail 9 Increased reliability 10 Fuel available concentrate Conversion kits available 049 30 cid Schnuerle ported engines Its sim ple just change heads fuel What waiting Dust off two-cycle DIESELIZE Send self-addressed stamped enve lope $100 infoation call 203-877-1670 between 730 pm and 930 pm EST DAVIS DIESEL DEVELOPMENT PO Box 141 Milford CT 06460 leader quiet combustion technology since 1976 April1987143 RC Scale/Wischers Continued page 45 responding advertisers mention read about ModelAviation cause serious damage body parts Always wear eye protection wind heavy wire 062-in diameter example person pulling vise-grip plier must use maximum muscle weight force wire closely around mandrel com pletely wound spring will open slightly larger outside diameter insufficient stretch ing during winding spring-back will exces sive resulting spring will probably fit space allotted Lighter wire needs less pull during winding local hobby shop source music wire cant improved upon material stainless steel spring wire will absorb energy music wire old standby modelers everywhere past 75 years Hobby shop wire diameters 015 020 025 032 047 055 062 possibly 078 Heavier wire beyond scope some what primitive winding procedure Commercial music wire sizes seemingly finite diameter range beginning 005 continuing 001-in increments through 042 continuing 002-in increments 080 tremendous variety choose springs can tailored exact specificationsbut modeling needs far less exacting hobby shop sizes will likely serve smaller sizes mentioned such 015 can used make tension springs apply load ends rigging wires biplanes order remove sag long wires wound mandrel 047 062-in diameter wire anchored mandrel hub means setscrew springs closewound turn wound tight contact 144 Model Aviation preceding turn vise-grip plier held side forces turns tight con tact result spring initial tension built means obtaining maximum stored energy minimum space extra tension available very instant coils begin separate Almost tension-type springs hooks end have initial tension wound during manufacture tensioning rigging wires spring has hook removed direct soldering wire Only other end has hook Heavier wire diameters 047 055 062 used shock-absorbing landing gears telescoping tubes wound com pression springs have evenly-spaced openings between coils adjusting length fin ished spring wind few turns close-wound end End coils can removed using cutoff grinding disc Dremel tool adjust spring length fit space crude methods winding always possible have spring come out exact length needed spring free length controlled closely watching space between coils winding strictly eyeball operation rare spring indeed comes mandrel usable item very first try high rate scrap-making process carefully save scrap springs hope some future Scale model will need spring dimensions present scrap has found its way airplane another trick making compression spring hold vise-grip right angle mandrel centerline two three revolutions swing plier wire off side small amount provide space between coils Near ing end winding swing again 900 position wind several last turns close-wound Producing two springs exactly alike primitive process can frustrating both needed landing gear legs isnt really necessary two within 10% being equal usable Add washers spacers increase length necessary cut off ends mentioned earlier Calculations find opti mum spacing between coils obtain desirable free length spring will help produce spring somewhere ballpark Professional modelmakers industrial plants have trick spacing between coils After first close-wound coils wound mandrel rotation stopped soft copper wire inserted between coils provide spacing requires second hole drilled through mandrel soft wire end spaced portion soft wire cut remainder spring close-wound two three turns landing gear springs desirable soften spring using active turns can wound space available Such spring has slow rate load build-up compressed prevents model being thrown back air hard landing too turns small-diameter wire spring will support models weight too turns large-diameter wire spring reaches its solid length after short deflectionand no longer spring small number turns large-diameter wire provides high load-rate reduces shock absorption because extreme stiffness Stress build-up wire may cause take set spring compressed its solid length coils closed occurs springs free length permanently reduced balance variables usually wire diameter number turns trialand-error calculations inserting values Continued page 146 rAIIJI makers EWWW HEAD LOCK 1-IEADLITE MODEL PRODUCTS CORP PO BOX 100 ALLAMUCHY NEW JERSEY 07820 following formula Load spring rate 0000d4 S D3 N terms have following meanings 11500000 torsional modulus elasticity music wire small d wire diameter large D springs mean diameter its outside diameter minus wire diameter N number active turns including closewound turns spring ends 8 constant formula gives us pounds per inch deflec tion beginning springs free length Adjust free length during winding space between coils keeping mind must fit within strut find load point springs deflection multiply rate determined means formula hy deflection decimal inches get load initial final positions landing-gear travel Remember spring already partially loaded re hound spring used landing gear full size practice Typically airplane weighing 12 lb spring wound 055-in-diameter wire outside diameter 406 having 22 active turns could installed within 500-in GD strut 12 lb distributed six lb leg main gear will produce deflection model rest about 4 dimension somewhat reduced because part models weight supported nose gear tail wheel hut reality ahsorbing landing shocks main gear Wound free length 262 such spring could deflect total 125 absorh landing load 17 lb legor roughly three times models weight spring GD 406 055-in -diameter wire will have inside diame ter 296 Because tendency increase diameter after winding spring wound 25-in-diameter mandrel length wire turn 11 22 turns plus two inactive turns end length wire needed shout 29 Add several inches gripping plier 36-in hohhy shop length wire sufficient spring As indication amount spring-hack wire after winding changing mandrel diameter 28 yields spring GD 43 Bob Dolly Wischer S-221 Lap/tam Peak Rd Delafleld WI 53018 RC Electrics/Kopski Continued page 47 once convenient meaningful way describe motor size early days now m view no longer good approach two ways can illustrated first commercially-made Electric system 05 motor eight 055 Ah 550 mAh cells Astro system gave years service fact still have well-worn motor recall measwing system perform ance specified prop operating power level just about 75 80 watts mind number stock 05 power Now understand new Astro cobalt 02 can operate about same power level Another way see such size ratings dubious value realize contemporary cobalt 05 fully capable handling over twice power first 05 system beyond new Astro FM cobalt 05 goes much farther regard Yet three motors about same physical size weight called OSs So real 05 Considering power-handling abilities Ive just described directly affect well such motors can fly given plane its no wonder would-be Electric fliers experienced ones well get confused Incidentally please note nowhere above did say mentioned motors has less power otherfor motors have power Rather motors have lack ability handle varying power levels Anyway seems clear enough 05 other such designation doesnt mean much anymore So think its time change Ithink its time appropriately describe standardize what meant motor size think modeling industry modeling consumer need standard makes sense wont become outdated changes technology new entries model motor field opinion Electric Aeromodeling Association EAA best-positioned group establish control matter think because EAA official Special Interest Group Electric designated AMA also think its right group because left itself bickering industry will never come up standards Finally Ithink time now Quite naturally Ive got some ideas own subject since Ive just opened up topical area am now going pass along Rememberyou read first Model Avia lion 146 Model Aviation 1 STAIM.ESS STEEL HEAD LOCK glow plug connector strength & long corrosion free life 2FIELD REPLACEABLE 1 2 AH Nicad 3Built FULLY AUTOIIATIC ON/OFF SWITCH prevent short circuits pocket tool box 4Charger LED INDICATOR available