SHOCK STRUTS Ed Radtke building Scale models back early 1930s asks about landing gear positions Eds letter follows number WW aircraft double axles hinged end opposite wheels also axle center ground shock cords stretched causing wheels splay out wards bottom inward top flight wheels dropped down maldng parallel other hand during Twenties shock absorber configuration reversed some aircraft ground wheels parallel flight cocked inwards bottom wider apart top same time wheels dropped down greater distance low fuselage centerline What you making Scale model aircraft Build flight ground configuration Either depending aes thetic appearance us have building Scale models over period years have con fronted situation air plane Back days flying Scale mod els Free Flight ignored changing po sition wheels load Most us fastened landing gear legs model wheels mounted assumed correct posi tion airplane ground reason ing nearly correct because model would spend almost its life grounded Flight time tiny part models life indeed flew World War models wheels mounted straight vertically viewed front reasoned new shock cords landing gear would correct position real life however shock cords weakened consid erably very short time photos WW aircraft show wheels canted sharply ward topsometimes drastically rub ber shock cords wrapped around split axle point immediately inboard wheels RC Scale WW models use elastic bands axle shock absorption approxi mately same position prototype rubber ages permit wheels sume scalelike canted position regard rubberbands incapable properly absorbing shock bad landings re placed new rubber Result model never gets chance look real ground truth slightly dilapidated appearance splayed wheels somewhat disturbing Scale modeler tighten replace 52 Model Aviation Radio Conoi Scale Bob Dolly Wischer 5-221 Lapham Peak Rd Delafleld WI 53018 Merrill Zimmermans latest engine project 3-cu-in 4-stroke twin built Wahi kit Lyle Pepino Bore stroke 125 Features oil sump pump Seen Toledo Bud Atkinsons Hawker Hurricane 1 1A scale weighs 195 lb uses Genoah G-38 power Bud made own retracts Finish K&B Super poxy flattener over Super Coverite hand-carved laminated prop Al Walkers Nicuport Xl R Proctor kit Unusual en gine Webra 90 Davis Diesel head Plane weighs 9 lb finished Super Coverite dope photos 1988 Mint Julep contest Under cowl Charles DuValls Fairchild PT-19 L Supertigre 2500 Starting Pilot kit 16-lb /8-scale WW Il-era trainer f ished Hobbypoxy Coverite glass cloth wings Well-detailed Aeronca Sedan R Steve Sauger also % scale weighs 13 lb uses OS 90 4-stroke power Finish Coverite Randolph dope Panel lines simulated using technique employing primer built up along edge masking tape Simulated rivets drops R/C-56 glue applied before painting flew 88 RC Scale World Champs rubberbands give model jaunty stance Aesthetically looks better right After WW oleo shock struts became common method absorbing landing loads modeler faced different set con ditions wheel position air ground changed greater degree ground oleos properly pumped up wheels near vertical viewed front Actually often canted slightly outward top several degrees nomencla ture condition camber angle reduce ground-looping tendencies aid tracking straight down runway idea borrowed automobile viewed above right left tires closer together front rear angle labeled toe-in angle could thing between zero couple degrees Scale models toe-in considered desirable tail-dragger models benefi cial effects has straight-line takeoff land ing full-size airplanes however could have rather drastic effect appearance tail-dragger towed backward mo del toe-in caused wheels spread away airplane centerline producing same ungainly appearance wheels canted apart ground level have whole series col ored documentation photos Douglas Mailplane exhibiting condition com pletely useless because contest judges may pos sibly regard wheel position normal fact came about plane being moved rearward before photos made brings us second condition Eds letter change wheel location ver tically load removed airplane leaves ground greatest realism models wheels should also move vertically present-day models effort made simulate oleo action landing gears out actually going trouble building real oleo struts may well some meticu lous modelers somewhere have done have vertical motion wheels telescop ing struts containing springs absorb landing shocks Weve photos explanations some RC Scale col umns years past full-size aircraft employ similar systems model lifts off ground takeoff wheels visibly drop down although amount travel some what less would true olco gear have seen full-size airplanes such verti cal travel can 8 model try position camber gle degree two models weight wheels lift-off angle increases couple degrees wheels drop down realism No measures wheel angle air critical viewers see model ground attempt place wheels correct position rest either vertical slightly wide top Working shock struts add realism taxiing rough ground model rolls side side rather bouncing stiffly single-strut landing gear seen almost modern aircraft poses entirely different problem Scale modeler Because bad landings made nose-low atti tude typical model gear legs have torsion spring wound wire strut material near top permits landing gear leg swing rearward thereby absorbing shock two direc tions assume Scale modeler has im proved flying landing technique suf Continued page 157 ch 4 Balsa & plywood construction Foam wing sheeted balsa Pre-built sanded components Hardware engine mount landing gear mci Complete building flying instructions PUT YOURSELF AT ThE CONTROLS OF PROVEN GREAT FlYING WARDIRD almost ready fly kits have wing loadings lighter trainers very docile air land like Cub building-to-flying time very minimal fine kits together skill imagination will make plane crowd pleaser field Retracts now available Strong Light Reilable Pneumatics kits come furnished fiberglass cowls Write CAll D&R Aircraft Mfg PO Box 23056 in TX 78736 512/288-2055 512/672-7023 Dealer Inquiries linwited Wingspan 60 Area 640 sq Fuealage Length 47 BY lbs 30-502 cycls snd 40-61 4 cycle angina Available Major Hobby Distributors S. Local Hobby Shop Afr Kra 4104 Lark Ln Houston TX 77025 171 31 680-8815 NEW Fourmost Flush Button Hatch Release Snaps __________________________ Noril~ ___________________________ Price $35 Flush Button allows modeler No 131 easy access hatch compart ment just finger tip Flush Button constructed lie completely flush surface hatch pro viding clean finishareodynamic~~ Molded white device may painted match finish Fourmost Products 4040 24TH AVENUE FOREST GROVE OR 97116 503 357-2732 December 1988 53 T-40 4 measures achieve 3 I have read fliers use YS Rossi engines have used OS several months still runs fine Would rec ommend three No Any three engines mentioned would job beginning Pattern fliers addition several other engines would also competitive lower AMA classes Included choices could Fox Eagle 60 K&B 61 Supertigre S61 Como 61 HP 61 HR 61 Surprised answer Remember question about what needed beginfling Pattern flier what top-level Pattern flier would require demands lowerlevel class patterns severe up per levels Consequently airplanes dont need capable can heavier dont need powerful engine bonus slightly less powerful engines dont cost much either 4 While Nats also noticed fliers aileron servos mounted outside wing reason clarify question what noticed aileron servos mounted wing about halfway out tip servo output shaft servo arm pushrod exposed aile ron driven externally pushrod tached horn aileron two reasons doing first positive control aileron conventional Z-link torque system could provide Most airplanes employ tech nique have half-span ailerons conven tional torque system would require long torque tube resulting springy aileron old-fashioned system involving bellcranks Out wing driven cen trally located servo operating long pushrods usu ally has unacceptable slop aileron doesnt come back same neutral point time Similar problems experienced using nylon pushrods have curved 900 centrally located servo second reason using aileron servos im bedded wing combat aileron flutter rigid aileron linkage higher flutter speed will conventional torque system has always plagued aileron flut ter because flexibility torque tube imbedded aileron servo located close aileron control horn avoids potential problem 5 How determine best length tuned pipe Ive paraphrased lost ques tian purposes brevity clarityR VP referred April 1988 column pp 133134 mentioned MACS put out good chart determining pipe length pipes also good estimate other manufacturers pipes could write whole column subject tuned pipes can really get essence next five para graphs ideal length tuned pipe function engine propeller airplane best have pipe length bit too long too short Making pipe too short results needle valve setting being excessively sensitive what airplane doing Longer-than-optimum pipe lengths take bit off maximum power also broaden out needle valve response Higher-pitched/larger-diameter propellers re quite longer pipe length lowerpitched/smaller-diameter propellers Optimum pipe length function engine rpm engine cant turn high-pitch/large-diameter prop fast can lower-pitch/smallerdiameter prop determine best pipe length must use trial error prop youve chosen length header pipe purchased set needle valve maximum engine rpm Cut header reset needle valve maximum rpm Note increase rpm Cut another try again Keep up until notice rpm isnt increasing much time shorten pipe Thats Id stop could continue cut smaller amounts pipe header until cant detect improvement cut next Thats peak length think its too short pipe maneuvers Okay now know best pipe length best prop used setting pipe length put another prop youll probably find different best pipe length Which prop best pipe length will give performance want dont know Thats up Nobody better judge whats right airplane Good luck Thanks Peter got whole column Out letter hope lot new Pattern fliers able derive some useful information RC Scale/Wischers Continued page 53 ficiently time really high-quality Scale model construction begins rearward deflec tion isnt longer necessary Scale model expected land prototypical manner tail low three-point landing taildragger mains tricycle gear Singlestrut gears usually angled slightly forward force vectors landing loads sup posedly directly along strut axis shock struts past 15 18 years PRECISION MODEL PRODUCTS MadeintheUSA BARSTOCK ALUMINUM SPINNERS Pan NaSize 11-150-B 1-112 T1-175-B .. 1314 T1-200-B 2 11-225-B.. 21/4 TT-226-B . 2114 FAt TT-250-B 2112 TT-251-B FAt .. TT-275-B.. 2-3/4 11-276-B.. 2-3/4 IFAI TT-300-B3 TT-301-B Il TT-325-B . 3-1/4 50-B.. 3-112 TT-375-B 4 TT-400-B etailApprox PriceWeight $1395058 oz 149509502 1595100gz 1695160oz 1895150oz 189519002 209517002 229522002 249520002 2695260oz 289525002 369534002 4995470oz 599552002 699557002 3 Pieces Cone Back Plale Relainer Screw Note 3 4 Blade Spinners Available Sizes Add $300 Per Spinner Pan No Size TT-140-A 1/4-28 1T-147-A 1/4-28/7mn tT610-A 6 x 10mm TT-710-A 10mm TT-516-A -24 TI-SiB-A5/1624/Bnn TT-810-A8 x lOun TT-825-A8 x 125mm TT-375-A318-24 TT-125-AlOx 125nm Retail Appros Price Weight S495 061 02 495 .O6loz 495 . 06302 495 02 495 176oz 49507602 495076oz 495 O7Soz 595 117 02 595 11502 3 Pieces Nul Washer arid Machined Bushing Add $350 Shipping Handling Prices suhiecl change wilhoul nolice ROMCO MFG INC OX 836 SOUTH HOUSTON TEXAS 77587 713 943-1867 December 1988 157 DIESELS PAW QUICKSTART 03 35 R/C STO Send $1 Info ERIC CLUTTON 913 Cedar Lane Tullahoma TN 37388 PROP NUT ADAPTORS V FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH Y HULL SIGN IN USE SINCE 1972 SEND SASE FOR CArALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066 Large Scale Miniasure Aircraft Denigo cod Dwine i-ib ilali iMAA 1488 1 16 Scam Anonc C-3 -65 wing27001pp 2 116 Scaio 59C-3 Holidive ing ape3000/pp 32-5116 Scoln 5BD5 Doontleno 93 wing30001pp 4 1/5 5coln AD-3 o5 Dooglon Okyteide3000/pp 5 High Wing enginne, Dee Piene2000/pp Send 295 go compiene nenolog DP Synnenne inn. 1842 1egienieii -macnan TX nose l7l3lggg-96407131054-0059 BALSA PRE FAB AIRCRAFT 40 TO 51 512 AESOMODEL SHARK-SS poo Soogo S~ooldn-o~og SHARK ST 60 opo Topee7 SooIdeoAg 05 W gCo 570cq SSIos FsnqlsCoo og ff A M Gn FIAsIGnoo bb.9~i INTRODUCTORY E AM OP i 9 nOODLING MC VISA COD AINGSWAY ENTEPPRISES SASE4506WILOACRES FOR CA ALOGHOUSTOI4 TX 77072 AIR WOLF EPOXY FIBERGLASS FUSELAGES TAKES MOST 50-60 MECHANICS OTHER MODELS AVAILABLE LARRY JOLLY MODEL PRODUCTS $20000 5501 WCOMO SANTA ANA CALIFORNIA 92703 714 826-6861 have telescoping steel tubes vertical motion Internal springs absorb shock real oleo strut oil forced through orifice ab sorb shock bounce models have never attempted exactly copy action use springs because merely store energy make bouncy landing inevitable secondary problem tendency strut hit bottom especially hard landing spring compresses its solid length strut mechanically reaches its motion limit models accompanied loud click sound metal metal followed im mediately model returning air spring snaps landing gear telescoping tubes quickly outward against downward stop another audible click taxiing rough ground clicks continuous avoid problem use smaller re bound spring bottom strut enclosed within Outer tube idea borrowed fullsize practice model struts travel approximate scale distance vertically look right both ground air FM rule changes 1987 FM plenary ses sion Paris dramatic change rule governing engine displacement limits Scale models top limit displacement removed completely blanket removal re strictions recognized time being con trary FAI general rule everything must have limit As result reconsideration general rule FAI Bureau its annual meeting last De cember has now placed top limit total dis placement 80cc 48 cu still very generous limit compared past example four-engined model could now have 1 2-cu-in four-stroke two-stroke engines real limiting factor remains 154-lb weight limit Its hard imagine 15lb airplane 48-cu-in engine ex ample pair Quadra 35s FM suggests Scale sound limits FAI Scale Subcommittee suggesting adoption 90 dB sound level upper limit three meters dis tance similar AMA objective con siderably less present FM limit 98 dB measurement made over hard sur face bit unrealistic us have sound level meters never fly hard surface until arrive Nats world championship scene would like see some comparative figures showing difference sound levels over various surfaces sheet plywood beneath model regarded hard surface no hard surface beneath model airborne opinion sound level should checked model suspended above surface specification should stipulate surface type None local clubs area operate bard surfaec Three club members have now invested purchase sound level meters relatively inexpensive units sold Radio Shack catalog No 33-2050 $2995 sound pickup means electret micro phone top reading 126 dB Response dis cretionary slow fast help minimize fluctu ation indicator needle sharp sound im pacts also adjustable C weighting characteristics measurements can made 500 10000 Hz range greatest sensitivity human ear Accuracy 2 dB 114 dB sound level have made comparisons found ters much closer tolerance range would indicate opinion AMA objec tives should require expensive equipment unreasonable testing conditions good response expected campaign reduce noise pollu tion Most important fact three club mem bers 6% have made investment indicates seriousness individuals regard efforts reduce noise club field nearest neighbors almost half-mile distant club members has spoken nearby neighbors asked specifically about noise par ticularly early morning assured yet have problem neighbors church will make effort maintain good standing sound level meters insurance Over pest several years have noted marked reduction noise Scale models time Howard Crispin made mention col umn about loudness Scale models flown Nats Because Scale models can quite heavy builders feel full input needed sometimes reluctant use effective muffler know muffler need reduce performance FM class lid now removed engine displacement no longer excuse flying good muf fler RC Helicopters/Jolly Continued page 54 Spectra packaged nicely trimmers switches intelligently arranged easy access have included pictorial layout Spectra transmitter help identif differ ent functions also nice see Airtron ics spent great deal effort send Spectra out usable instruction manual man ual boasts 21 pages features ouly radio specifications also method setting separate trimmer also has troubleahooting graph last page After looking through manual snap get Shuttle trimmed out flying right Typical sensible layout radio ability work trimmers Helicopters rotors turning because trims located front trans mitter covered fold-down access door So fine tuning can bring ship out hover pull transmitter door open make needed adjustments give another try really like featureits clean use radio also has other common Air tronics features such easy-aecess transmitter battery pack carrying handle doubles stand course easy access transmitter RF module idiot lights also nice touch flashing away let know somethings shouldnt Spectra came optional contest ser vos word outstanding using another manufacturers radio would worth consider looking set Airtronics servos fa vorite chopper feature high power quick response very tight no slop visible output arm market new system dont check Airtronics Spectra 7H out Its real nice radio sensible price go along its sensible functions Next month tend dwell deeper Spectra show what can doand get other part report concerns GMP/ Hirobos neat little Shuttle XX little white Shuttle has really upgraded new thicker side frames tail housing redesigned ro tor head servo trays well ball bearing supports throughout new Shuttle has great performance Autorotations inverted flight superb size class would hard imagine better performer chose power Shuttle XX 05 32 FSR-H Its obvious two designed other effort minimize potential boom strike main rotor blade hitting tail boom Ed Hirobo lengthened Shuttles main rotor shaft Personally felt didnt af fect hovering autorotations did detract rolling capabilities So really wringing out Shuttles might think about installing original shorter main shaft standard GMP paddles combination will let hot-dog hearts content 158 Model Aviation
Edition: Model Aviation - 1988/12
Page Numbers: 52, 53, 157, 158
SHOCK STRUTS Ed Radtke building Scale models back early 1930s asks about landing gear positions Eds letter follows number WW aircraft double axles hinged end opposite wheels also axle center ground shock cords stretched causing wheels splay out wards bottom inward top flight wheels dropped down maldng parallel other hand during Twenties shock absorber configuration reversed some aircraft ground wheels parallel flight cocked inwards bottom wider apart top same time wheels dropped down greater distance low fuselage centerline What you making Scale model aircraft Build flight ground configuration Either depending aes thetic appearance us have building Scale models over period years have con fronted situation air plane Back days flying Scale mod els Free Flight ignored changing po sition wheels load Most us fastened landing gear legs model wheels mounted assumed correct posi tion airplane ground reason ing nearly correct because model would spend almost its life grounded Flight time tiny part models life indeed flew World War models wheels mounted straight vertically viewed front reasoned new shock cords landing gear would correct position real life however shock cords weakened consid erably very short time photos WW aircraft show wheels canted sharply ward topsometimes drastically rub ber shock cords wrapped around split axle point immediately inboard wheels RC Scale WW models use elastic bands axle shock absorption approxi mately same position prototype rubber ages permit wheels sume scalelike canted position regard rubberbands incapable properly absorbing shock bad landings re placed new rubber Result model never gets chance look real ground truth slightly dilapidated appearance splayed wheels somewhat disturbing Scale modeler tighten replace 52 Model Aviation Radio Conoi Scale Bob Dolly Wischer 5-221 Lapham Peak Rd Delafleld WI 53018 Merrill Zimmermans latest engine project 3-cu-in 4-stroke twin built Wahi kit Lyle Pepino Bore stroke 125 Features oil sump pump Seen Toledo Bud Atkinsons Hawker Hurricane 1 1A scale weighs 195 lb uses Genoah G-38 power Bud made own retracts Finish K&B Super poxy flattener over Super Coverite hand-carved laminated prop Al Walkers Nicuport Xl R Proctor kit Unusual en gine Webra 90 Davis Diesel head Plane weighs 9 lb finished Super Coverite dope photos 1988 Mint Julep contest Under cowl Charles DuValls Fairchild PT-19 L Supertigre 2500 Starting Pilot kit 16-lb /8-scale WW Il-era trainer f ished Hobbypoxy Coverite glass cloth wings Well-detailed Aeronca Sedan R Steve Sauger also % scale weighs 13 lb uses OS 90 4-stroke power Finish Coverite Randolph dope Panel lines simulated using technique employing primer built up along edge masking tape Simulated rivets drops R/C-56 glue applied before painting flew 88 RC Scale World Champs rubberbands give model jaunty stance Aesthetically looks better right After WW oleo shock struts became common method absorbing landing loads modeler faced different set con ditions wheel position air ground changed greater degree ground oleos properly pumped up wheels near vertical viewed front Actually often canted slightly outward top several degrees nomencla ture condition camber angle reduce ground-looping tendencies aid tracking straight down runway idea borrowed automobile viewed above right left tires closer together front rear angle labeled toe-in angle could thing between zero couple degrees Scale models toe-in considered desirable tail-dragger models benefi cial effects has straight-line takeoff land ing full-size airplanes however could have rather drastic effect appearance tail-dragger towed backward mo del toe-in caused wheels spread away airplane centerline producing same ungainly appearance wheels canted apart ground level have whole series col ored documentation photos Douglas Mailplane exhibiting condition com pletely useless because contest judges may pos sibly regard wheel position normal fact came about plane being moved rearward before photos made brings us second condition Eds letter change wheel location ver tically load removed airplane leaves ground greatest realism models wheels should also move vertically present-day models effort made simulate oleo action landing gears out actually going trouble building real oleo struts may well some meticu lous modelers somewhere have done have vertical motion wheels telescop ing struts containing springs absorb landing shocks Weve photos explanations some RC Scale col umns years past full-size aircraft employ similar systems model lifts off ground takeoff wheels visibly drop down although amount travel some what less would true olco gear have seen full-size airplanes such verti cal travel can 8 model try position camber gle degree two models weight wheels lift-off angle increases couple degrees wheels drop down realism No measures wheel angle air critical viewers see model ground attempt place wheels correct position rest either vertical slightly wide top Working shock struts add realism taxiing rough ground model rolls side side rather bouncing stiffly single-strut landing gear seen almost modern aircraft poses entirely different problem Scale modeler Because bad landings made nose-low atti tude typical model gear legs have torsion spring wound wire strut material near top permits landing gear leg swing rearward thereby absorbing shock two direc tions assume Scale modeler has im proved flying landing technique suf Continued page 157 ch 4 Balsa & plywood construction Foam wing sheeted balsa Pre-built sanded components Hardware engine mount landing gear mci Complete building flying instructions PUT YOURSELF AT ThE CONTROLS OF PROVEN GREAT FlYING WARDIRD almost ready fly kits have wing loadings lighter trainers very docile air land like Cub building-to-flying time very minimal fine kits together skill imagination will make plane crowd pleaser field Retracts now available Strong Light Reilable Pneumatics kits come furnished fiberglass cowls Write CAll D&R Aircraft Mfg PO Box 23056 in TX 78736 512/288-2055 512/672-7023 Dealer Inquiries linwited Wingspan 60 Area 640 sq Fuealage Length 47 BY lbs 30-502 cycls snd 40-61 4 cycle angina Available Major Hobby Distributors S. Local Hobby Shop Afr Kra 4104 Lark Ln Houston TX 77025 171 31 680-8815 NEW Fourmost Flush Button Hatch Release Snaps __________________________ Noril~ ___________________________ Price $35 Flush Button allows modeler No 131 easy access hatch compart ment just finger tip Flush Button constructed lie completely flush surface hatch pro viding clean finishareodynamic~~ Molded white device may painted match finish Fourmost Products 4040 24TH AVENUE FOREST GROVE OR 97116 503 357-2732 December 1988 53 T-40 4 measures achieve 3 I have read fliers use YS Rossi engines have used OS several months still runs fine Would rec ommend three No Any three engines mentioned would job beginning Pattern fliers addition several other engines would also competitive lower AMA classes Included choices could Fox Eagle 60 K&B 61 Supertigre S61 Como 61 HP 61 HR 61 Surprised answer Remember question about what needed beginfling Pattern flier what top-level Pattern flier would require demands lowerlevel class patterns severe up per levels Consequently airplanes dont need capable can heavier dont need powerful engine bonus slightly less powerful engines dont cost much either 4 While Nats also noticed fliers aileron servos mounted outside wing reason clarify question what noticed aileron servos mounted wing about halfway out tip servo output shaft servo arm pushrod exposed aile ron driven externally pushrod tached horn aileron two reasons doing first positive control aileron conventional Z-link torque system could provide Most airplanes employ tech nique have half-span ailerons conven tional torque system would require long torque tube resulting springy aileron old-fashioned system involving bellcranks Out wing driven cen trally located servo operating long pushrods usu ally has unacceptable slop aileron doesnt come back same neutral point time Similar problems experienced using nylon pushrods have curved 900 centrally located servo second reason using aileron servos im bedded wing combat aileron flutter rigid aileron linkage higher flutter speed will conventional torque system has always plagued aileron flut ter because flexibility torque tube imbedded aileron servo located close aileron control horn avoids potential problem 5 How determine best length tuned pipe Ive paraphrased lost ques tian purposes brevity clarityR VP referred April 1988 column pp 133134 mentioned MACS put out good chart determining pipe length pipes also good estimate other manufacturers pipes could write whole column subject tuned pipes can really get essence next five para graphs ideal length tuned pipe function engine propeller airplane best have pipe length bit too long too short Making pipe too short results needle valve setting being excessively sensitive what airplane doing Longer-than-optimum pipe lengths take bit off maximum power also broaden out needle valve response Higher-pitched/larger-diameter propellers re quite longer pipe length lowerpitched/smaller-diameter propellers Optimum pipe length function engine rpm engine cant turn high-pitch/large-diameter prop fast can lower-pitch/smallerdiameter prop determine best pipe length must use trial error prop youve chosen length header pipe purchased set needle valve maximum engine rpm Cut header reset needle valve maximum rpm Note increase rpm Cut another try again Keep up until notice rpm isnt increasing much time shorten pipe Thats Id stop could continue cut smaller amounts pipe header until cant detect improvement cut next Thats peak length think its too short pipe maneuvers Okay now know best pipe length best prop used setting pipe length put another prop youll probably find different best pipe length Which prop best pipe length will give performance want dont know Thats up Nobody better judge whats right airplane Good luck Thanks Peter got whole column Out letter hope lot new Pattern fliers able derive some useful information RC Scale/Wischers Continued page 53 ficiently time really high-quality Scale model construction begins rearward deflec tion isnt longer necessary Scale model expected land prototypical manner tail low three-point landing taildragger mains tricycle gear Singlestrut gears usually angled slightly forward force vectors landing loads sup posedly directly along strut axis shock struts past 15 18 years PRECISION MODEL PRODUCTS MadeintheUSA BARSTOCK ALUMINUM SPINNERS Pan NaSize 11-150-B 1-112 T1-175-B .. 1314 T1-200-B 2 11-225-B.. 21/4 TT-226-B . 2114 FAt TT-250-B 2112 TT-251-B FAt .. TT-275-B.. 2-3/4 11-276-B.. 2-3/4 IFAI TT-300-B3 TT-301-B Il TT-325-B . 3-1/4 50-B.. 3-112 TT-375-B 4 TT-400-B etailApprox PriceWeight $1395058 oz 149509502 1595100gz 1695160oz 1895150oz 189519002 209517002 229522002 249520002 2695260oz 289525002 369534002 4995470oz 599552002 699557002 3 Pieces Cone Back Plale Relainer Screw Note 3 4 Blade Spinners Available Sizes Add $300 Per Spinner Pan No Size TT-140-A 1/4-28 1T-147-A 1/4-28/7mn tT610-A 6 x 10mm TT-710-A 10mm TT-516-A -24 TI-SiB-A5/1624/Bnn TT-810-A8 x lOun TT-825-A8 x 125mm TT-375-A318-24 TT-125-AlOx 125nm Retail Appros Price Weight S495 061 02 495 .O6loz 495 . 06302 495 02 495 176oz 49507602 495076oz 495 O7Soz 595 117 02 595 11502 3 Pieces Nul Washer arid Machined Bushing Add $350 Shipping Handling Prices suhiecl change wilhoul nolice ROMCO MFG INC OX 836 SOUTH HOUSTON TEXAS 77587 713 943-1867 December 1988 157 DIESELS PAW QUICKSTART 03 35 R/C STO Send $1 Info ERIC CLUTTON 913 Cedar Lane Tullahoma TN 37388 PROP NUT ADAPTORS V FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH Y HULL SIGN IN USE SINCE 1972 SEND SASE FOR CArALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066 Large Scale Miniasure Aircraft Denigo cod Dwine i-ib ilali iMAA 1488 1 16 Scam Anonc C-3 -65 wing27001pp 2 116 Scaio 59C-3 Holidive ing ape3000/pp 32-5116 Scoln 5BD5 Doontleno 93 wing30001pp 4 1/5 5coln AD-3 o5 Dooglon Okyteide3000/pp 5 High Wing enginne, Dee Piene2000/pp Send 295 go compiene nenolog DP Synnenne inn. 1842 1egienieii -macnan TX nose l7l3lggg-96407131054-0059 BALSA PRE FAB AIRCRAFT 40 TO 51 512 AESOMODEL SHARK-SS poo Soogo S~ooldn-o~og SHARK ST 60 opo Topee7 SooIdeoAg 05 W gCo 570cq SSIos FsnqlsCoo og ff A M Gn FIAsIGnoo bb.9~i INTRODUCTORY E AM OP i 9 nOODLING MC VISA COD AINGSWAY ENTEPPRISES SASE4506WILOACRES FOR CA ALOGHOUSTOI4 TX 77072 AIR WOLF EPOXY FIBERGLASS FUSELAGES TAKES MOST 50-60 MECHANICS OTHER MODELS AVAILABLE LARRY JOLLY MODEL PRODUCTS $20000 5501 WCOMO SANTA ANA CALIFORNIA 92703 714 826-6861 have telescoping steel tubes vertical motion Internal springs absorb shock real oleo strut oil forced through orifice ab sorb shock bounce models have never attempted exactly copy action use springs because merely store energy make bouncy landing inevitable secondary problem tendency strut hit bottom especially hard landing spring compresses its solid length strut mechanically reaches its motion limit models accompanied loud click sound metal metal followed im mediately model returning air spring snaps landing gear telescoping tubes quickly outward against downward stop another audible click taxiing rough ground clicks continuous avoid problem use smaller re bound spring bottom strut enclosed within Outer tube idea borrowed fullsize practice model struts travel approximate scale distance vertically look right both ground air FM rule changes 1987 FM plenary ses sion Paris dramatic change rule governing engine displacement limits Scale models top limit displacement removed completely blanket removal re strictions recognized time being con trary FAI general rule everything must have limit As result reconsideration general rule FAI Bureau its annual meeting last De cember has now placed top limit total dis placement 80cc 48 cu still very generous limit compared past example four-engined model could now have 1 2-cu-in four-stroke two-stroke engines real limiting factor remains 154-lb weight limit Its hard imagine 15lb airplane 48-cu-in engine ex ample pair Quadra 35s FM suggests Scale sound limits FAI Scale Subcommittee suggesting adoption 90 dB sound level upper limit three meters dis tance similar AMA objective con siderably less present FM limit 98 dB measurement made over hard sur face bit unrealistic us have sound level meters never fly hard surface until arrive Nats world championship scene would like see some comparative figures showing difference sound levels over various surfaces sheet plywood beneath model regarded hard surface no hard surface beneath model airborne opinion sound level should checked model suspended above surface specification should stipulate surface type None local clubs area operate bard surfaec Three club members have now invested purchase sound level meters relatively inexpensive units sold Radio Shack catalog No 33-2050 $2995 sound pickup means electret micro phone top reading 126 dB Response dis cretionary slow fast help minimize fluctu ation indicator needle sharp sound im pacts also adjustable C weighting characteristics measurements can made 500 10000 Hz range greatest sensitivity human ear Accuracy 2 dB 114 dB sound level have made comparisons found ters much closer tolerance range would indicate opinion AMA objec tives should require expensive equipment unreasonable testing conditions good response expected campaign reduce noise pollu tion Most important fact three club mem bers 6% have made investment indicates seriousness individuals regard efforts reduce noise club field nearest neighbors almost half-mile distant club members has spoken nearby neighbors asked specifically about noise par ticularly early morning assured yet have problem neighbors church will make effort maintain good standing sound level meters insurance Over pest several years have noted marked reduction noise Scale models time Howard Crispin made mention col umn about loudness Scale models flown Nats Because Scale models can quite heavy builders feel full input needed sometimes reluctant use effective muffler know muffler need reduce performance FM class lid now removed engine displacement no longer excuse flying good muf fler RC Helicopters/Jolly Continued page 54 Spectra packaged nicely trimmers switches intelligently arranged easy access have included pictorial layout Spectra transmitter help identif differ ent functions also nice see Airtron ics spent great deal effort send Spectra out usable instruction manual man ual boasts 21 pages features ouly radio specifications also method setting separate trimmer also has troubleahooting graph last page After looking through manual snap get Shuttle trimmed out flying right Typical sensible layout radio ability work trimmers Helicopters rotors turning because trims located front trans mitter covered fold-down access door So fine tuning can bring ship out hover pull transmitter door open make needed adjustments give another try really like featureits clean use radio also has other common Air tronics features such easy-aecess transmitter battery pack carrying handle doubles stand course easy access transmitter RF module idiot lights also nice touch flashing away let know somethings shouldnt Spectra came optional contest ser vos word outstanding using another manufacturers radio would worth consider looking set Airtronics servos fa vorite chopper feature high power quick response very tight no slop visible output arm market new system dont check Airtronics Spectra 7H out Its real nice radio sensible price go along its sensible functions Next month tend dwell deeper Spectra show what can doand get other part report concerns GMP/ Hirobos neat little Shuttle XX little white Shuttle has really upgraded new thicker side frames tail housing redesigned ro tor head servo trays well ball bearing supports throughout new Shuttle has great performance Autorotations inverted flight superb size class would hard imagine better performer chose power Shuttle XX 05 32 FSR-H Its obvious two designed other effort minimize potential boom strike main rotor blade hitting tail boom Ed Hirobo lengthened Shuttles main rotor shaft Personally felt didnt af fect hovering autorotations did detract rolling capabilities So really wringing out Shuttles might think about installing original shorter main shaft standard GMP paddles combination will let hot-dog hearts content 158 Model Aviation
Edition: Model Aviation - 1988/12
Page Numbers: 52, 53, 157, 158
SHOCK STRUTS Ed Radtke building Scale models back early 1930s asks about landing gear positions Eds letter follows number WW aircraft double axles hinged end opposite wheels also axle center ground shock cords stretched causing wheels splay out wards bottom inward top flight wheels dropped down maldng parallel other hand during Twenties shock absorber configuration reversed some aircraft ground wheels parallel flight cocked inwards bottom wider apart top same time wheels dropped down greater distance low fuselage centerline What you making Scale model aircraft Build flight ground configuration Either depending aes thetic appearance us have building Scale models over period years have con fronted situation air plane Back days flying Scale mod els Free Flight ignored changing po sition wheels load Most us fastened landing gear legs model wheels mounted assumed correct posi tion airplane ground reason ing nearly correct because model would spend almost its life grounded Flight time tiny part models life indeed flew World War models wheels mounted straight vertically viewed front reasoned new shock cords landing gear would correct position real life however shock cords weakened consid erably very short time photos WW aircraft show wheels canted sharply ward topsometimes drastically rub ber shock cords wrapped around split axle point immediately inboard wheels RC Scale WW models use elastic bands axle shock absorption approxi mately same position prototype rubber ages permit wheels sume scalelike canted position regard rubberbands incapable properly absorbing shock bad landings re placed new rubber Result model never gets chance look real ground truth slightly dilapidated appearance splayed wheels somewhat disturbing Scale modeler tighten replace 52 Model Aviation Radio Conoi Scale Bob Dolly Wischer 5-221 Lapham Peak Rd Delafleld WI 53018 Merrill Zimmermans latest engine project 3-cu-in 4-stroke twin built Wahi kit Lyle Pepino Bore stroke 125 Features oil sump pump Seen Toledo Bud Atkinsons Hawker Hurricane 1 1A scale weighs 195 lb uses Genoah G-38 power Bud made own retracts Finish K&B Super poxy flattener over Super Coverite hand-carved laminated prop Al Walkers Nicuport Xl R Proctor kit Unusual en gine Webra 90 Davis Diesel head Plane weighs 9 lb finished Super Coverite dope photos 1988 Mint Julep contest Under cowl Charles DuValls Fairchild PT-19 L Supertigre 2500 Starting Pilot kit 16-lb /8-scale WW Il-era trainer f ished Hobbypoxy Coverite glass cloth wings Well-detailed Aeronca Sedan R Steve Sauger also % scale weighs 13 lb uses OS 90 4-stroke power Finish Coverite Randolph dope Panel lines simulated using technique employing primer built up along edge masking tape Simulated rivets drops R/C-56 glue applied before painting flew 88 RC Scale World Champs rubberbands give model jaunty stance Aesthetically looks better right After WW oleo shock struts became common method absorbing landing loads modeler faced different set con ditions wheel position air ground changed greater degree ground oleos properly pumped up wheels near vertical viewed front Actually often canted slightly outward top several degrees nomencla ture condition camber angle reduce ground-looping tendencies aid tracking straight down runway idea borrowed automobile viewed above right left tires closer together front rear angle labeled toe-in angle could thing between zero couple degrees Scale models toe-in considered desirable tail-dragger models benefi cial effects has straight-line takeoff land ing full-size airplanes however could have rather drastic effect appearance tail-dragger towed backward mo del toe-in caused wheels spread away airplane centerline producing same ungainly appearance wheels canted apart ground level have whole series col ored documentation photos Douglas Mailplane exhibiting condition com pletely useless because contest judges may pos sibly regard wheel position normal fact came about plane being moved rearward before photos made brings us second condition Eds letter change wheel location ver tically load removed airplane leaves ground greatest realism models wheels should also move vertically present-day models effort made simulate oleo action landing gears out actually going trouble building real oleo struts may well some meticu lous modelers somewhere have done have vertical motion wheels telescop ing struts containing springs absorb landing shocks Weve photos explanations some RC Scale col umns years past full-size aircraft employ similar systems model lifts off ground takeoff wheels visibly drop down although amount travel some what less would true olco gear have seen full-size airplanes such verti cal travel can 8 model try position camber gle degree two models weight wheels lift-off angle increases couple degrees wheels drop down realism No measures wheel angle air critical viewers see model ground attempt place wheels correct position rest either vertical slightly wide top Working shock struts add realism taxiing rough ground model rolls side side rather bouncing stiffly single-strut landing gear seen almost modern aircraft poses entirely different problem Scale modeler Because bad landings made nose-low atti tude typical model gear legs have torsion spring wound wire strut material near top permits landing gear leg swing rearward thereby absorbing shock two direc tions assume Scale modeler has im proved flying landing technique suf Continued page 157 ch 4 Balsa & plywood construction Foam wing sheeted balsa Pre-built sanded components Hardware engine mount landing gear mci Complete building flying instructions PUT YOURSELF AT ThE CONTROLS OF PROVEN GREAT FlYING WARDIRD almost ready fly kits have wing loadings lighter trainers very docile air land like Cub building-to-flying time very minimal fine kits together skill imagination will make plane crowd pleaser field Retracts now available Strong Light Reilable Pneumatics kits come furnished fiberglass cowls Write CAll D&R Aircraft Mfg PO Box 23056 in TX 78736 512/288-2055 512/672-7023 Dealer Inquiries linwited Wingspan 60 Area 640 sq Fuealage Length 47 BY lbs 30-502 cycls snd 40-61 4 cycle angina Available Major Hobby Distributors S. Local Hobby Shop Afr Kra 4104 Lark Ln Houston TX 77025 171 31 680-8815 NEW Fourmost Flush Button Hatch Release Snaps __________________________ Noril~ ___________________________ Price $35 Flush Button allows modeler No 131 easy access hatch compart ment just finger tip Flush Button constructed lie completely flush surface hatch pro viding clean finishareodynamic~~ Molded white device may painted match finish Fourmost Products 4040 24TH AVENUE FOREST GROVE OR 97116 503 357-2732 December 1988 53 T-40 4 measures achieve 3 I have read fliers use YS Rossi engines have used OS several months still runs fine Would rec ommend three No Any three engines mentioned would job beginning Pattern fliers addition several other engines would also competitive lower AMA classes Included choices could Fox Eagle 60 K&B 61 Supertigre S61 Como 61 HP 61 HR 61 Surprised answer Remember question about what needed beginfling Pattern flier what top-level Pattern flier would require demands lowerlevel class patterns severe up per levels Consequently airplanes dont need capable can heavier dont need powerful engine bonus slightly less powerful engines dont cost much either 4 While Nats also noticed fliers aileron servos mounted outside wing reason clarify question what noticed aileron servos mounted wing about halfway out tip servo output shaft servo arm pushrod exposed aile ron driven externally pushrod tached horn aileron two reasons doing first positive control aileron conventional Z-link torque system could provide Most airplanes employ tech nique have half-span ailerons conven tional torque system would require long torque tube resulting springy aileron old-fashioned system involving bellcranks Out wing driven cen trally located servo operating long pushrods usu ally has unacceptable slop aileron doesnt come back same neutral point time Similar problems experienced using nylon pushrods have curved 900 centrally located servo second reason using aileron servos im bedded wing combat aileron flutter rigid aileron linkage higher flutter speed will conventional torque system has always plagued aileron flut ter because flexibility torque tube imbedded aileron servo located close aileron control horn avoids potential problem 5 How determine best length tuned pipe Ive paraphrased lost ques tian purposes brevity clarityR VP referred April 1988 column pp 133134 mentioned MACS put out good chart determining pipe length pipes also good estimate other manufacturers pipes could write whole column subject tuned pipes can really get essence next five para graphs ideal length tuned pipe function engine propeller airplane best have pipe length bit too long too short Making pipe too short results needle valve setting being excessively sensitive what airplane doing Longer-than-optimum pipe lengths take bit off maximum power also broaden out needle valve response Higher-pitched/larger-diameter propellers re quite longer pipe length lowerpitched/smaller-diameter propellers Optimum pipe length function engine rpm engine cant turn high-pitch/large-diameter prop fast can lower-pitch/smallerdiameter prop determine best pipe length must use trial error prop youve chosen length header pipe purchased set needle valve maximum engine rpm Cut header reset needle valve maximum rpm Note increase rpm Cut another try again Keep up until notice rpm isnt increasing much time shorten pipe Thats Id stop could continue cut smaller amounts pipe header until cant detect improvement cut next Thats peak length think its too short pipe maneuvers Okay now know best pipe length best prop used setting pipe length put another prop youll probably find different best pipe length Which prop best pipe length will give performance want dont know Thats up Nobody better judge whats right airplane Good luck Thanks Peter got whole column Out letter hope lot new Pattern fliers able derive some useful information RC Scale/Wischers Continued page 53 ficiently time really high-quality Scale model construction begins rearward deflec tion isnt longer necessary Scale model expected land prototypical manner tail low three-point landing taildragger mains tricycle gear Singlestrut gears usually angled slightly forward force vectors landing loads sup posedly directly along strut axis shock struts past 15 18 years PRECISION MODEL PRODUCTS MadeintheUSA BARSTOCK ALUMINUM SPINNERS Pan NaSize 11-150-B 1-112 T1-175-B .. 1314 T1-200-B 2 11-225-B.. 21/4 TT-226-B . 2114 FAt TT-250-B 2112 TT-251-B FAt .. TT-275-B.. 2-3/4 11-276-B.. 2-3/4 IFAI TT-300-B3 TT-301-B Il TT-325-B . 3-1/4 50-B.. 3-112 TT-375-B 4 TT-400-B etailApprox PriceWeight $1395058 oz 149509502 1595100gz 1695160oz 1895150oz 189519002 209517002 229522002 249520002 2695260oz 289525002 369534002 4995470oz 599552002 699557002 3 Pieces Cone Back Plale Relainer Screw Note 3 4 Blade Spinners Available Sizes Add $300 Per Spinner Pan No Size TT-140-A 1/4-28 1T-147-A 1/4-28/7mn tT610-A 6 x 10mm TT-710-A 10mm TT-516-A -24 TI-SiB-A5/1624/Bnn TT-810-A8 x lOun TT-825-A8 x 125mm TT-375-A318-24 TT-125-AlOx 125nm Retail Appros Price Weight S495 061 02 495 .O6loz 495 . 06302 495 02 495 176oz 49507602 495076oz 495 O7Soz 595 117 02 595 11502 3 Pieces Nul Washer arid Machined Bushing Add $350 Shipping Handling Prices suhiecl change wilhoul nolice ROMCO MFG INC OX 836 SOUTH HOUSTON TEXAS 77587 713 943-1867 December 1988 157 DIESELS PAW QUICKSTART 03 35 R/C STO Send $1 Info ERIC CLUTTON 913 Cedar Lane Tullahoma TN 37388 PROP NUT ADAPTORS V FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH Y HULL SIGN IN USE SINCE 1972 SEND SASE FOR CArALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066 Large Scale Miniasure Aircraft Denigo cod Dwine i-ib ilali iMAA 1488 1 16 Scam Anonc C-3 -65 wing27001pp 2 116 Scaio 59C-3 Holidive ing ape3000/pp 32-5116 Scoln 5BD5 Doontleno 93 wing30001pp 4 1/5 5coln AD-3 o5 Dooglon Okyteide3000/pp 5 High Wing enginne, Dee Piene2000/pp Send 295 go compiene nenolog DP Synnenne inn. 1842 1egienieii -macnan TX nose l7l3lggg-96407131054-0059 BALSA PRE FAB AIRCRAFT 40 TO 51 512 AESOMODEL SHARK-SS poo Soogo S~ooldn-o~og SHARK ST 60 opo Topee7 SooIdeoAg 05 W gCo 570cq SSIos FsnqlsCoo og ff A M Gn FIAsIGnoo bb.9~i INTRODUCTORY E AM OP i 9 nOODLING MC VISA COD AINGSWAY ENTEPPRISES SASE4506WILOACRES FOR CA ALOGHOUSTOI4 TX 77072 AIR WOLF EPOXY FIBERGLASS FUSELAGES TAKES MOST 50-60 MECHANICS OTHER MODELS AVAILABLE LARRY JOLLY MODEL PRODUCTS $20000 5501 WCOMO SANTA ANA CALIFORNIA 92703 714 826-6861 have telescoping steel tubes vertical motion Internal springs absorb shock real oleo strut oil forced through orifice ab sorb shock bounce models have never attempted exactly copy action use springs because merely store energy make bouncy landing inevitable secondary problem tendency strut hit bottom especially hard landing spring compresses its solid length strut mechanically reaches its motion limit models accompanied loud click sound metal metal followed im mediately model returning air spring snaps landing gear telescoping tubes quickly outward against downward stop another audible click taxiing rough ground clicks continuous avoid problem use smaller re bound spring bottom strut enclosed within Outer tube idea borrowed fullsize practice model struts travel approximate scale distance vertically look right both ground air FM rule changes 1987 FM plenary ses sion Paris dramatic change rule governing engine displacement limits Scale models top limit displacement removed completely blanket removal re strictions recognized time being con trary FAI general rule everything must have limit As result reconsideration general rule FAI Bureau its annual meeting last De cember has now placed top limit total dis placement 80cc 48 cu still very generous limit compared past example four-engined model could now have 1 2-cu-in four-stroke two-stroke engines real limiting factor remains 154-lb weight limit Its hard imagine 15lb airplane 48-cu-in engine ex ample pair Quadra 35s FM suggests Scale sound limits FAI Scale Subcommittee suggesting adoption 90 dB sound level upper limit three meters dis tance similar AMA objective con siderably less present FM limit 98 dB measurement made over hard sur face bit unrealistic us have sound level meters never fly hard surface until arrive Nats world championship scene would like see some comparative figures showing difference sound levels over various surfaces sheet plywood beneath model regarded hard surface no hard surface beneath model airborne opinion sound level should checked model suspended above surface specification should stipulate surface type None local clubs area operate bard surfaec Three club members have now invested purchase sound level meters relatively inexpensive units sold Radio Shack catalog No 33-2050 $2995 sound pickup means electret micro phone top reading 126 dB Response dis cretionary slow fast help minimize fluctu ation indicator needle sharp sound im pacts also adjustable C weighting characteristics measurements can made 500 10000 Hz range greatest sensitivity human ear Accuracy 2 dB 114 dB sound level have made comparisons found ters much closer tolerance range would indicate opinion AMA objec tives should require expensive equipment unreasonable testing conditions good response expected campaign reduce noise pollu tion Most important fact three club mem bers 6% have made investment indicates seriousness individuals regard efforts reduce noise club field nearest neighbors almost half-mile distant club members has spoken nearby neighbors asked specifically about noise par ticularly early morning assured yet have problem neighbors church will make effort maintain good standing sound level meters insurance Over pest several years have noted marked reduction noise Scale models time Howard Crispin made mention col umn about loudness Scale models flown Nats Because Scale models can quite heavy builders feel full input needed sometimes reluctant use effective muffler know muffler need reduce performance FM class lid now removed engine displacement no longer excuse flying good muf fler RC Helicopters/Jolly Continued page 54 Spectra packaged nicely trimmers switches intelligently arranged easy access have included pictorial layout Spectra transmitter help identif differ ent functions also nice see Airtron ics spent great deal effort send Spectra out usable instruction manual man ual boasts 21 pages features ouly radio specifications also method setting separate trimmer also has troubleahooting graph last page After looking through manual snap get Shuttle trimmed out flying right Typical sensible layout radio ability work trimmers Helicopters rotors turning because trims located front trans mitter covered fold-down access door So fine tuning can bring ship out hover pull transmitter door open make needed adjustments give another try really like featureits clean use radio also has other common Air tronics features such easy-aecess transmitter battery pack carrying handle doubles stand course easy access transmitter RF module idiot lights also nice touch flashing away let know somethings shouldnt Spectra came optional contest ser vos word outstanding using another manufacturers radio would worth consider looking set Airtronics servos fa vorite chopper feature high power quick response very tight no slop visible output arm market new system dont check Airtronics Spectra 7H out Its real nice radio sensible price go along its sensible functions Next month tend dwell deeper Spectra show what can doand get other part report concerns GMP/ Hirobos neat little Shuttle XX little white Shuttle has really upgraded new thicker side frames tail housing redesigned ro tor head servo trays well ball bearing supports throughout new Shuttle has great performance Autorotations inverted flight superb size class would hard imagine better performer chose power Shuttle XX 05 32 FSR-H Its obvious two designed other effort minimize potential boom strike main rotor blade hitting tail boom Ed Hirobo lengthened Shuttles main rotor shaft Personally felt didnt af fect hovering autorotations did detract rolling capabilities So really wringing out Shuttles might think about installing original shorter main shaft standard GMP paddles combination will let hot-dog hearts content 158 Model Aviation
Edition: Model Aviation - 1988/12
Page Numbers: 52, 53, 157, 158
SHOCK STRUTS Ed Radtke building Scale models back early 1930s asks about landing gear positions Eds letter follows number WW aircraft double axles hinged end opposite wheels also axle center ground shock cords stretched causing wheels splay out wards bottom inward top flight wheels dropped down maldng parallel other hand during Twenties shock absorber configuration reversed some aircraft ground wheels parallel flight cocked inwards bottom wider apart top same time wheels dropped down greater distance low fuselage centerline What you making Scale model aircraft Build flight ground configuration Either depending aes thetic appearance us have building Scale models over period years have con fronted situation air plane Back days flying Scale mod els Free Flight ignored changing po sition wheels load Most us fastened landing gear legs model wheels mounted assumed correct posi tion airplane ground reason ing nearly correct because model would spend almost its life grounded Flight time tiny part models life indeed flew World War models wheels mounted straight vertically viewed front reasoned new shock cords landing gear would correct position real life however shock cords weakened consid erably very short time photos WW aircraft show wheels canted sharply ward topsometimes drastically rub ber shock cords wrapped around split axle point immediately inboard wheels RC Scale WW models use elastic bands axle shock absorption approxi mately same position prototype rubber ages permit wheels sume scalelike canted position regard rubberbands incapable properly absorbing shock bad landings re placed new rubber Result model never gets chance look real ground truth slightly dilapidated appearance splayed wheels somewhat disturbing Scale modeler tighten replace 52 Model Aviation Radio Conoi Scale Bob Dolly Wischer 5-221 Lapham Peak Rd Delafleld WI 53018 Merrill Zimmermans latest engine project 3-cu-in 4-stroke twin built Wahi kit Lyle Pepino Bore stroke 125 Features oil sump pump Seen Toledo Bud Atkinsons Hawker Hurricane 1 1A scale weighs 195 lb uses Genoah G-38 power Bud made own retracts Finish K&B Super poxy flattener over Super Coverite hand-carved laminated prop Al Walkers Nicuport Xl R Proctor kit Unusual en gine Webra 90 Davis Diesel head Plane weighs 9 lb finished Super Coverite dope photos 1988 Mint Julep contest Under cowl Charles DuValls Fairchild PT-19 L Supertigre 2500 Starting Pilot kit 16-lb /8-scale WW Il-era trainer f ished Hobbypoxy Coverite glass cloth wings Well-detailed Aeronca Sedan R Steve Sauger also % scale weighs 13 lb uses OS 90 4-stroke power Finish Coverite Randolph dope Panel lines simulated using technique employing primer built up along edge masking tape Simulated rivets drops R/C-56 glue applied before painting flew 88 RC Scale World Champs rubberbands give model jaunty stance Aesthetically looks better right After WW oleo shock struts became common method absorbing landing loads modeler faced different set con ditions wheel position air ground changed greater degree ground oleos properly pumped up wheels near vertical viewed front Actually often canted slightly outward top several degrees nomencla ture condition camber angle reduce ground-looping tendencies aid tracking straight down runway idea borrowed automobile viewed above right left tires closer together front rear angle labeled toe-in angle could thing between zero couple degrees Scale models toe-in considered desirable tail-dragger models benefi cial effects has straight-line takeoff land ing full-size airplanes however could have rather drastic effect appearance tail-dragger towed backward mo del toe-in caused wheels spread away airplane centerline producing same ungainly appearance wheels canted apart ground level have whole series col ored documentation photos Douglas Mailplane exhibiting condition com pletely useless because contest judges may pos sibly regard wheel position normal fact came about plane being moved rearward before photos made brings us second condition Eds letter change wheel location ver tically load removed airplane leaves ground greatest realism models wheels should also move vertically present-day models effort made simulate oleo action landing gears out actually going trouble building real oleo struts may well some meticu lous modelers somewhere have done have vertical motion wheels telescop ing struts containing springs absorb landing shocks Weve photos explanations some RC Scale col umns years past full-size aircraft employ similar systems model lifts off ground takeoff wheels visibly drop down although amount travel some what less would true olco gear have seen full-size airplanes such verti cal travel can 8 model try position camber gle degree two models weight wheels lift-off angle increases couple degrees wheels drop down realism No measures wheel angle air critical viewers see model ground attempt place wheels correct position rest either vertical slightly wide top Working shock struts add realism taxiing rough ground model rolls side side rather bouncing stiffly single-strut landing gear seen almost modern aircraft poses entirely different problem Scale modeler Because bad landings made nose-low atti tude typical model gear legs have torsion spring wound wire strut material near top permits landing gear leg swing rearward thereby absorbing shock two direc tions assume Scale modeler has im proved flying landing technique suf Continued page 157 ch 4 Balsa & plywood construction Foam wing sheeted balsa Pre-built sanded components Hardware engine mount landing gear mci Complete building flying instructions PUT YOURSELF AT ThE CONTROLS OF PROVEN GREAT FlYING WARDIRD almost ready fly kits have wing loadings lighter trainers very docile air land like Cub building-to-flying time very minimal fine kits together skill imagination will make plane crowd pleaser field Retracts now available Strong Light Reilable Pneumatics kits come furnished fiberglass cowls Write CAll D&R Aircraft Mfg PO Box 23056 in TX 78736 512/288-2055 512/672-7023 Dealer Inquiries linwited Wingspan 60 Area 640 sq Fuealage Length 47 BY lbs 30-502 cycls snd 40-61 4 cycle angina Available Major Hobby Distributors S. Local Hobby Shop Afr Kra 4104 Lark Ln Houston TX 77025 171 31 680-8815 NEW Fourmost Flush Button Hatch Release Snaps __________________________ Noril~ ___________________________ Price $35 Flush Button allows modeler No 131 easy access hatch compart ment just finger tip Flush Button constructed lie completely flush surface hatch pro viding clean finishareodynamic~~ Molded white device may painted match finish Fourmost Products 4040 24TH AVENUE FOREST GROVE OR 97116 503 357-2732 December 1988 53 T-40 4 measures achieve 3 I have read fliers use YS Rossi engines have used OS several months still runs fine Would rec ommend three No Any three engines mentioned would job beginning Pattern fliers addition several other engines would also competitive lower AMA classes Included choices could Fox Eagle 60 K&B 61 Supertigre S61 Como 61 HP 61 HR 61 Surprised answer Remember question about what needed beginfling Pattern flier what top-level Pattern flier would require demands lowerlevel class patterns severe up per levels Consequently airplanes dont need capable can heavier dont need powerful engine bonus slightly less powerful engines dont cost much either 4 While Nats also noticed fliers aileron servos mounted outside wing reason clarify question what noticed aileron servos mounted wing about halfway out tip servo output shaft servo arm pushrod exposed aile ron driven externally pushrod tached horn aileron two reasons doing first positive control aileron conventional Z-link torque system could provide Most airplanes employ tech nique have half-span ailerons conven tional torque system would require long torque tube resulting springy aileron old-fashioned system involving bellcranks Out wing driven cen trally located servo operating long pushrods usu ally has unacceptable slop aileron doesnt come back same neutral point time Similar problems experienced using nylon pushrods have curved 900 centrally located servo second reason using aileron servos im bedded wing combat aileron flutter rigid aileron linkage higher flutter speed will conventional torque system has always plagued aileron flut ter because flexibility torque tube imbedded aileron servo located close aileron control horn avoids potential problem 5 How determine best length tuned pipe Ive paraphrased lost ques tian purposes brevity clarityR VP referred April 1988 column pp 133134 mentioned MACS put out good chart determining pipe length pipes also good estimate other manufacturers pipes could write whole column subject tuned pipes can really get essence next five para graphs ideal length tuned pipe function engine propeller airplane best have pipe length bit too long too short Making pipe too short results needle valve setting being excessively sensitive what airplane doing Longer-than-optimum pipe lengths take bit off maximum power also broaden out needle valve response Higher-pitched/larger-diameter propellers re quite longer pipe length lowerpitched/smaller-diameter propellers Optimum pipe length function engine rpm engine cant turn high-pitch/large-diameter prop fast can lower-pitch/smallerdiameter prop determine best pipe length must use trial error prop youve chosen length header pipe purchased set needle valve maximum engine rpm Cut header reset needle valve maximum rpm Note increase rpm Cut another try again Keep up until notice rpm isnt increasing much time shorten pipe Thats Id stop could continue cut smaller amounts pipe header until cant detect improvement cut next Thats peak length think its too short pipe maneuvers Okay now know best pipe length best prop used setting pipe length put another prop youll probably find different best pipe length Which prop best pipe length will give performance want dont know Thats up Nobody better judge whats right airplane Good luck Thanks Peter got whole column Out letter hope lot new Pattern fliers able derive some useful information RC Scale/Wischers Continued page 53 ficiently time really high-quality Scale model construction begins rearward deflec tion isnt longer necessary Scale model expected land prototypical manner tail low three-point landing taildragger mains tricycle gear Singlestrut gears usually angled slightly forward force vectors landing loads sup posedly directly along strut axis shock struts past 15 18 years PRECISION MODEL PRODUCTS MadeintheUSA BARSTOCK ALUMINUM SPINNERS Pan NaSize 11-150-B 1-112 T1-175-B .. 1314 T1-200-B 2 11-225-B.. 21/4 TT-226-B . 2114 FAt TT-250-B 2112 TT-251-B FAt .. TT-275-B.. 2-3/4 11-276-B.. 2-3/4 IFAI TT-300-B3 TT-301-B Il TT-325-B . 3-1/4 50-B.. 3-112 TT-375-B 4 TT-400-B etailApprox PriceWeight $1395058 oz 149509502 1595100gz 1695160oz 1895150oz 189519002 209517002 229522002 249520002 2695260oz 289525002 369534002 4995470oz 599552002 699557002 3 Pieces Cone Back Plale Relainer Screw Note 3 4 Blade Spinners Available Sizes Add $300 Per Spinner Pan No Size TT-140-A 1/4-28 1T-147-A 1/4-28/7mn tT610-A 6 x 10mm TT-710-A 10mm TT-516-A -24 TI-SiB-A5/1624/Bnn TT-810-A8 x lOun TT-825-A8 x 125mm TT-375-A318-24 TT-125-AlOx 125nm Retail Appros Price Weight S495 061 02 495 .O6loz 495 . 06302 495 02 495 176oz 49507602 495076oz 495 O7Soz 595 117 02 595 11502 3 Pieces Nul Washer arid Machined Bushing Add $350 Shipping Handling Prices suhiecl change wilhoul nolice ROMCO MFG INC OX 836 SOUTH HOUSTON TEXAS 77587 713 943-1867 December 1988 157 DIESELS PAW QUICKSTART 03 35 R/C STO Send $1 Info ERIC CLUTTON 913 Cedar Lane Tullahoma TN 37388 PROP NUT ADAPTORS V FOAM CORE FLOATS PLANS AND KITS WE OFFER SELECTION OF FLOAT PLANS AND KITS FOR 4 12 POUND AIRPLANES WITH Y HULL SIGN IN USE SINCE 1972 SEND SASE FOR CArALOG SHEET KIRCHER R/C PRODUCTS INC 9 SHEFFIELD WAY CLARK NJ 07066 Large Scale Miniasure Aircraft Denigo cod Dwine i-ib ilali iMAA 1488 1 16 Scam Anonc C-3 -65 wing27001pp 2 116 Scaio 59C-3 Holidive ing ape3000/pp 32-5116 Scoln 5BD5 Doontleno 93 wing30001pp 4 1/5 5coln AD-3 o5 Dooglon Okyteide3000/pp 5 High Wing enginne, Dee Piene2000/pp Send 295 go compiene nenolog DP Synnenne inn. 1842 1egienieii -macnan TX nose l7l3lggg-96407131054-0059 BALSA PRE FAB AIRCRAFT 40 TO 51 512 AESOMODEL SHARK-SS poo Soogo S~ooldn-o~og SHARK ST 60 opo Topee7 SooIdeoAg 05 W gCo 570cq SSIos FsnqlsCoo og ff A M Gn FIAsIGnoo bb.9~i INTRODUCTORY E AM OP i 9 nOODLING MC VISA COD AINGSWAY ENTEPPRISES SASE4506WILOACRES FOR CA ALOGHOUSTOI4 TX 77072 AIR WOLF EPOXY FIBERGLASS FUSELAGES TAKES MOST 50-60 MECHANICS OTHER MODELS AVAILABLE LARRY JOLLY MODEL PRODUCTS $20000 5501 WCOMO SANTA ANA CALIFORNIA 92703 714 826-6861 have telescoping steel tubes vertical motion Internal springs absorb shock real oleo strut oil forced through orifice ab sorb shock bounce models have never attempted exactly copy action use springs because merely store energy make bouncy landing inevitable secondary problem tendency strut hit bottom especially hard landing spring compresses its solid length strut mechanically reaches its motion limit models accompanied loud click sound metal metal followed im mediately model returning air spring snaps landing gear telescoping tubes quickly outward against downward stop another audible click taxiing rough ground clicks continuous avoid problem use smaller re bound spring bottom strut enclosed within Outer tube idea borrowed fullsize practice model struts travel approximate scale distance vertically look right both ground air FM rule changes 1987 FM plenary ses sion Paris dramatic change rule governing engine displacement limits Scale models top limit displacement removed completely blanket removal re strictions recognized time being con trary FAI general rule everything must have limit As result reconsideration general rule FAI Bureau its annual meeting last De cember has now placed top limit total dis placement 80cc 48 cu still very generous limit compared past example four-engined model could now have 1 2-cu-in four-stroke two-stroke engines real limiting factor remains 154-lb weight limit Its hard imagine 15lb airplane 48-cu-in engine ex ample pair Quadra 35s FM suggests Scale sound limits FAI Scale Subcommittee suggesting adoption 90 dB sound level upper limit three meters dis tance similar AMA objective con siderably less present FM limit 98 dB measurement made over hard sur face bit unrealistic us have sound level meters never fly hard surface until arrive Nats world championship scene would like see some comparative figures showing difference sound levels over various surfaces sheet plywood beneath model regarded hard surface no hard surface beneath model airborne opinion sound level should checked model suspended above surface specification should stipulate surface type None local clubs area operate bard surfaec Three club members have now invested purchase sound level meters relatively inexpensive units sold Radio Shack catalog No 33-2050 $2995 sound pickup means electret micro phone top reading 126 dB Response dis cretionary slow fast help minimize fluctu ation indicator needle sharp sound im pacts also adjustable C weighting characteristics measurements can made 500 10000 Hz range greatest sensitivity human ear Accuracy 2 dB 114 dB sound level have made comparisons found ters much closer tolerance range would indicate opinion AMA objec tives should require expensive equipment unreasonable testing conditions good response expected campaign reduce noise pollu tion Most important fact three club mem bers 6% have made investment indicates seriousness individuals regard efforts reduce noise club field nearest neighbors almost half-mile distant club members has spoken nearby neighbors asked specifically about noise par ticularly early morning assured yet have problem neighbors church will make effort maintain good standing sound level meters insurance Over pest several years have noted marked reduction noise Scale models time Howard Crispin made mention col umn about loudness Scale models flown Nats Because Scale models can quite heavy builders feel full input needed sometimes reluctant use effective muffler know muffler need reduce performance FM class lid now removed engine displacement no longer excuse flying good muf fler RC Helicopters/Jolly Continued page 54 Spectra packaged nicely trimmers switches intelligently arranged easy access have included pictorial layout Spectra transmitter help identif differ ent functions also nice see Airtron ics spent great deal effort send Spectra out usable instruction manual man ual boasts 21 pages features ouly radio specifications also method setting separate trimmer also has troubleahooting graph last page After looking through manual snap get Shuttle trimmed out flying right Typical sensible layout radio ability work trimmers Helicopters rotors turning because trims located front trans mitter covered fold-down access door So fine tuning can bring ship out hover pull transmitter door open make needed adjustments give another try really like featureits clean use radio also has other common Air tronics features such easy-aecess transmitter battery pack carrying handle doubles stand course easy access transmitter RF module idiot lights also nice touch flashing away let know somethings shouldnt Spectra came optional contest ser vos word outstanding using another manufacturers radio would worth consider looking set Airtronics servos fa vorite chopper feature high power quick response very tight no slop visible output arm market new system dont check Airtronics Spectra 7H out Its real nice radio sensible price go along its sensible functions Next month tend dwell deeper Spectra show what can doand get other part report concerns GMP/ Hirobos neat little Shuttle XX little white Shuttle has really upgraded new thicker side frames tail housing redesigned ro tor head servo trays well ball bearing supports throughout new Shuttle has great performance Autorotations inverted flight superb size class would hard imagine better performer chose power Shuttle XX 05 32 FSR-H Its obvious two designed other effort minimize potential boom strike main rotor blade hitting tail boom Ed Hirobo lengthened Shuttles main rotor shaft Personally felt didnt af fect hovering autorotations did detract rolling capabilities So really wringing out Shuttles might think about installing original shorter main shaft standard GMP paddles combination will let hot-dog hearts content 158 Model Aviation