IF REE FLIGHT THINK fun using rubber power choice numerous variables tailor power model propeller desired flight performance months column some intro ductory concepts may helpful yet expert rubber fliers Torque twisting force purposes discussion torque power energy same thing Torque easily measured torque plotted graph against turns curve results shown Figure 1 amount torque given number turns represents power point area under broken line graph represents total energy available apparent necessary approach maximum turns motor get full performance Most energy comes last 20% turns unwinding rubber has short powerful burst followed 2 0 eli 0 0 C C U eel C C OLD-TIMERS d drop-off power slowly diminishing power rapid change can cause serious trim problems especially certain types models factor can contribute sharp knee power curve type quality rubber Good purpose rubber has torque vs turns curve rather shallow concave curve poor rubber will tend have J shape sharp angle between cruise power initial burst power know power required particular model setup climb horizontal line can added graph energy above linethat area under torque curveis energy available climb remaining energy below horizontal line goes slow descent cruise apparent given motor lower airplane weight lowering horizontal line will shift total zjjjFigure 1 n Ci 0/ C Increasing turns Increased twisting forcetorqueplotted against increased turns rubber motor results upward curve shown area below dotted line represents total energy available motor Inferior rubber would give curve like dashed line energy climb Isnt wonderful education gives us ability explain obvious convenience let us use modern Wakefield explain next point provides fixed model weight/wing area/weight rubber situation 40 grams rubber Figure 2 shows approximate curves 40-gram motor arranged 16 8 4 strands -in strip have drawn hypothetical line climb power variable cross section motor since weight remains constant length motor varies Less cross section fewer strands results longer motor number turns possible also changes Turns per unit length varies cross section inverse fashion means smaller cross section turns per inch Since Continued page 179 76 Model Aviation ly informative entertaining highly recommended Dave Thornburgs new book Speak Model Airplane meaningful us models have important part lives Dave understands such treat visit someone does understand isnt Bill Bakers Earl Stahl-designed Skyfarer typical scale models has propeller diameter somewhat limited landing gear length will best long braided motor minimal cross section will produce some climb See text Figure 2 B C Increasing turns rubber motor Approximate curves 40-gram motor arranged 16 8 4 strands A-in strip Broken line represents climb power Variable cross section motor constant weight length varies Less cross section fewer strands results longer motor 1-.Custom Balsa Die Cutting2 Balsa Sheets745/16 X 14880104 1/8x 12x24613 753/8 x 1-/25194105 3/16x 12x24363 36 48 38 1/8x 1/413 18- 1 1/16 228 40 39 1/8 3/814 19176 1/2 x 279 105 106 1/4x 12x24420 XX.f76B107 3/32x12x481004 21/16x332 44 40 1/8x1/217 24- \76C 3 1/16x 4537141 3/16x 3/1613 ~1081/8x12x481149 4Balsa Blocks1093/16X 12x48726 3/32x2355042 3/16x3/817 216 121/4x12x48838 5 3/32 x 3395343 3/16 x 1/22231 6 3/32x4679244 1/4x1/4182777 1/sx262 112 110B 71/8 x 23854451/4 x 3/81930782 x 2 74 130 ilOC IEVRIOODS792 x 3 90149SpruceSticks 81/8 x 35069461/4 x 1/220 34D JEVV803 x 3 1192253648 91/8x477104471/4x3/43445 813 x 4 1602991111/8 x 1/81723 103/16 x 24462481/4 x 14360 ustom Cut Balsa1121/8x 1/42128 113/16 x 35879495/16 x 5/162432 Quality Prices 81B1131/8 x 3/82333 123/16 x 491121503/8 x 3/827 42AAA Quality Ecuadorian Balsa 81C1143/16x3/162939 131/4 x 25172513/8 x 1/23153 Sanded Close Tolerances Balsa Planks361151/4 x 1/43652 141/4x37093523/8x3/44863 1285 N Union Street821x21571161/4x3/84158 151/4 x 4110134533/8 x 16573 Stockton CA 9520583lx 32191171/4 x 1/24766 165/16x26082541/2x 1/241 55841x42931181/4x 16789 175/16 x 382110551/2 x 3/453711 209-464-0180852x22311195/16 x 5/164362 185/16 x 4139185561/2 x 16487862x 33351205/16 x 1/24875 193/8x26895575/8x5/85472 E C L872x44751215/16x3/46789 203/8 x 390128583/3 x 3/47598883 x 35151223/8 x 3/85264 213/8x 4165230593/4 x 184111 ace Lite Ply893x47151233/8x 1/26381 221/2 x 283116601 x 1104139 Low Cost Door Skin 8981241/2 x 1/26992 231/2 x 3 109 155 608torButkheads& FuselageSides 89C1251/2 7101 241/2X 4 230 268 60C1/8x6x48 125 y Light 1258 248118x 12x48 225901/8x6x24 115 125C 24CBalsaTapered911/8x 12x24173 BassSticks AileronStock BUS Hours 800-500 PST M-F921/8 x 24 x 243453648 BalsaSticks3648We accept VISA MasterCard931/8x 6x 481731263/16 x 3/162837 261/16x 1/163648611/4 x 143 Checks & COD 94 1/8x 12x48 345 127 3/16 x 1/4 24 30 0611611/4 x 1-/450 70 ping Handling $500 95 1/4x6x24 201 128 3/16 x 3/8 31 38 271/16 x 1/80914621/4 x 1- 1/57 82 COD add $450 96 1/4 x 12 x 24 259 129 3/16 x 1/2 37 46 631/4 90 nimum Order $2500 97 1/4 x 6 x 48 259 130 3/16 x 3/4 48 60 281/16 x 3/161016 litornia Residents98x 12x485181311/4 x 1/43442 291/16 x 1/41018645/16 x 1/259 84 301/16 x 3/81120655/16 94 dd 6h% Sales Tas 988 132 1/4 x 3/8 39 49 311/16x 1/214 24 66 3/8x 1/2659298C133 1/4x3/46480 134 3/8x3/84860 323/32 x 3/3207 11 67 3/8 x 274 105BalsaPly Birch135 3/8 x 1/256 70 333/32x1/80914683/8x2/284122 TrailingEdge993/32x6x122531363/8x3/47290 343/32x1/41318691/2X 1/28011536481001/8x6x123111371/2x 1/27290 353/32x3/81419701/2x290125711/8x 1/218311013/16x6x122191381/2x3/496120 363/32x 1/2 17 24 708723/16x 3/42950 102 1/4x6x 12 242 1388 371/8 x 1/8 09 13 70C731/4 x 13661 103 3/32x 12x24 503 138C Contact Us Kitting Needs FF Duration/Murphy Continued page 176 circuit battery Because feel bit ridiculous running across grassy fields WPAFB nice sunny days lights have headlamp circuit Road riding different story its simple task ride along flip switch necessary Hank also compliments Honda folks electronic design feature automatically kicks booster coil triples charging rate headlamps turned Also generator designed match normal battery drain bike use way no regulator required system Well anyway Roy Rogers always said Happy trails thanks Hank info See ya downwind ylon/Hager Continued page 162 go good fiberglass supply house buy some resin dye will match color cockpit interior black case will prevent visible white line inside canopy white microballoon-and-epoxy mixture attached canopy Make sure work fillet lines pleasing Once get close dip finger water run along fillet will smooth out epoxy try make perfect well sandpaper 23 Once fillet dry sand contour pleasing Fill depressed areas DAP Vinyl Spackle hardware store easier work apply epoxy sands much easier replace slow-cure epoxy spackle because no strength spackle know have heen tempted because easy work hut aint no free lunches 24 Now stand back congratulate yourself first-rate job paint airplane concerned getting scratches canopy sanding fuselage can removed progressively finer grits sandpaper up 2000-grit spray clear topcoat airplane tiny scratches will just go away canopy will look like molded fuselage Good Luck ld-Timer/Baker Continued paqe 76 nature gives us no free lunch what give up get turns torque per turn varies directly cross section long small cross-section motor gives long slow run rather subdued burst what desired indoor flying outdoor scale models Such motor might also best certain Old-Timer sport duration models will come back short 16-strand motor gives rapid climb may hard control trim because rapid changes power level model could near-vertical climb throttle chopped amount down side thrust required may excessive efficient use remaining power power can controllednote available energy goes climbthere isnt much cruise dont want sort power curve typical scale model typical scalelike Old-Timer sport model smallish stab center gravity 30% chord model designed taskthat has large lifting stabilizer permits center-of-gravity 60% further aft will able use motor power curve similar 16-strand example good results actual modern Wakefield practice March 1993 179 4000 diflerent22000 3-view drawings color FOTO-PAAKSincluding KOkU-FAN Antiques Military Civilian Helicopters Sailpianes Catalog/Guide $500Overseas $1006 TJLTIMATESPORT RC I205 East Asktend/PO Boo 727/Soda Springs Idoko 93276 agegoc tn-stet3995d73742FsrCurherlnln Send SAsE usable range power 10 16 strands equivalent 20 32 strands /s thickness rubber varies somewhat too length rubber given number strands constant total weight may vary may see series rear peg holes Wakefields Coupes have fixed rules rubber weight flying competitively models no weight rule rubber such SAM Old-Timer events Mulvihill found helped made motors constant length thickness rubber varied adjusted number strands weight near constant kept models trim little center-of-gravity shift power change motors changed example standard motor Lanzo 1940 Stick 34-in length 85 90 grams number strands varied 30 34 /s depending thickness rubber kept number strands constant cross section varied Therefore power level shape torque curve varied affected trim Affecting trim almost always bad real world modem Wakefield flying usable motors run about 16 10 strands een 14 gives rapid rather short runs needed climb average rather windy conditions 10 12 range gives longer slower climb desired early morning dead-air BILL EFFINGER5 SAYS Only PIann Pat1ern Sets grce assorted designs want have selected hest classic designs stall hors yea choose troer patterns pat jmpotant ecdusioe teats 9/3ScetecSssn5 170 l4d org span 90 ngth pain ont areaS sin RC 22 Cli engines 17 los RC3S-5 9~Cessna 170 RC6S-5$149S 9/3 Seat MONOCOUPE 90A 128 srgnpanh2 Ia h2liOsqrn wing area Fon20 35010 e nor RC3S-4 9/3 Scale PIPER TRI-PACER PA22 1 1h-/ wing span 2390 sq reng area 20 1i 010 engines 4-5 ci SIC approc n2Ibs Or- sacrall lengli RC3S-3 9/3 Scat PIPER CUB J-3 l1-9nirg span 90 lerglhOhOOsq wing arts ass ac 2i 1030010 engines RC3S-2 rounds dead-air performance reflects efficient use power under ideal conditions weather during average contest day shorter faster run will likely better expenditure power controlled some extent propeller addition converting torque thrust functions air brake control rate energy release general rubber models best large propellers 25% moreeven 50% wingspan excessive means 12-in propeller 24-in model might look funny could fly well scale models scalelike Old-Timer sport duration models landing gear length puts limits propeller diameter best choice long motor limited cross section type torque curve Let get specific casemy AceWhitman Albatross small cabintype ship about 30-in span Pharis kit provides plastic P-30-type propeller 9-in diameter plans show balsa propeller 11-in diameter plastic propeller too low pitch liking As have explained previous columns plastic rubber model props seem run about 08 10 pitch/diameter ratio too low believe line propellers 125 P/D ratio produced would money bank Anyway decided fly model first plastic propeller 9/4 Scale ALBATROS DVa 99 eingspan72-/ leegnh2572nq wing area t3- 23 010 engines 405 lhlCn2 Es RCOS-1 7$2400 9/4 Scale SE5A gg10 wingspan 222g pa neng area 791022 engines RCOS-7S24a 9/4 SCale SPAD C-XIII 79rIe wIng span 2120 sq etrg area 13 31 engrnet Capable llyer captures innaginatne RCOS-8 9/4 SC$t FOKKER DR-i TRIPLANE 72 aeng span n7725g snng anea.79 100 engtror ROOS-6 9/4 SCale SOPWITH CAMEL F1 ha veng span illO sq wing area1I en Sb RIG Flpreord 9 SolId sonst ROOS-1 1 9/4 Scale FOKKER 0-ViI 99 wingspan 2220 sq wing area 90 1o2SClD engine 35 oh 11 En RCQS-5S24at first motor ten strands 3A6-inwide 24-in long model has lifting stabilizer felt would handle CG about 50% did add about 1/2 oz lead nose sticking sheet reinforcement insideout sight Wow Too much power exciting first few seconds went eight strands 24-in long about 3/oo down right thrust trimmed model climbed rapidly made smooth transition power glide glide acceptable satisfied because wanted longer slower climb what enjoy watching end several choices open to get what wanted could keep same propeller same motor remake fewer strands greater length advantage would would keep total weight center gravity same lower-crosssection motor greater length would give longer slower run Possibly six strands would just right lets say would give too little time-of-climb power model would land before winds half spent other hand could add strands back eight againbut keep new length would increase cross section torque giving greater climb would also increase total weight model problem because model light might need increase ballast center-of-gravity adjustment Most motor aft 114 S NIEUPORT28 80r/ wing span- 1660 sq wing area 78 23 OlD engine 4 cli RIO 11 lbs RCQS-1 8 $24 115 Scat FAIRCHILD 24 145wngspanSchR/C 22to 35 OlD engine appros 17 lbs less RIO radii & inline ye sons RO3S-6 $3455 119 Scat FAIRCHILD 24 72-/ wing span 5 engines RO6S-6$14se * Prices complete plans sub assembly & detailed parts lists PLEASE ADD $300 shIppIng mailIng tube New Plan Sets brochure $100 WE TECHNICAL SERVICES Sea Island GA 31561-0246 180 Model Aviation 4Ce~ Recognised @ GSA CertifiedAedesoe F lie NoFile No..j Ps E26226LR25154 tt5 Only certitied Checks meney orders accepted Minimum order 91400 lenthree packages 094 Poorerpoles 9490 per peckage * 9299 shipping handlingl CT residents add sales nan Pices subiect change notice DEAIER INQUIRIES INVITED luthet infonmenion dna er pt cos send SASS Business Cad no SERMOS R/C SNAP CONNECTORS Inc Cedar Corners Station Box 16787 Stamford CT 06905 12031 322-6294 roern nycgsurteses AlunrLendingGear CleenCencpyoceilekle guildersKitS2n5 Sheeedhit93b5 OnlannShoeredllirgaOg FULL-SIZE PLANS 732 Long-Wing ARIA$475 Wing plan ARIA #719 Sept 92 MA designed Bill Winter 99-in span 63-oz Variable flap system Compared short wing Aria has increased LID lower sink rate flatter turns Aggressive soarer Forgiving nice fly trainer 10-6 11-6 folding prop Four channels 1 plan sheet No 193 StIletto CL Stool model McDonald nnnner 1976 1580 1962 FAI World Chanrpn$ 375 No262 Croshnoster CL crash-prool rome Tcoosjzos1S/SSand 35/4Spoooer$ 125 No3101930 Fleel Blylsee PC Spon Scale 35/40 posset nod 4-channel Sponn 56 1/5 scale 2 plan sheets$ 025 No 314 Oroke II PC Ken Willard s hying boat ton 3-channel 15 ponoer Fly fonn lend osith removable sean$ 375 No 326 Taylor Cob RC Don Srull s Schoolyani Scala 10045 ponhen 2-3 channel Spann 50 in$ 350 No 332 Zephyr RC semall 2-channel Glider tam hand-loonch taco thernnal am siope nooring$ 200 No 306 Loser 200 PC Sport Scale replica channpionshiy Aerobatic lion FordS posse 45 channol an sheets0 1075 No 447 112A Miss Anrerleos PC Old Tcner 1/28 Tenaca model 1am 045 51050 2channols0 650 No 539 Siedt0r Slow-Motion 10 PC Taillesstlying ooing ton 15 passer Spans 60 3 channel0 350 No578 Oehwoloor 1266 PC Goader-scale Sailplane Spans 125 2 plan Sheets5 1475 No301 Gee Bee Model Y PC Golden Age Racer Spans 72-in 15 scale tar 60 passes 3 plan sheets$ 1175 No 009 Mortob PC Slepe-Soaring Salplane Spans 41 in. 2 PC channels0 425 Ne 096 Coronet 100 PCAasst Sid-Tinne enlarged 150% Spans 72 FOr 40- 4-strakeI30- 2-etlake0 650 No603 Sparrow Idasek P30 FE Coerpetition robber-pacoen plane voon 1907 NaIn Spans 3D in0 225 No 646 WIntee Howk FE Robber-passer Cooped Hicet contpntitioo plane Spans 47 in$ 375 No606 4760 BC Opeelol PC Aenobatic sped plane 10140 pooser Spans Olin 3 pIne sheets$ 1075 No 604 Torsenot RCTrainer/Spadsterstyledaherthe F14 Spano6o Far 40/61 passer 4 plan sheet5 1525 No 661 Etttbry-Onotie FE Enrbrya End orance robber passer plane Spans 205 in$ 200 No667 AT4 CL Senriscale profile Stonten tar 35140 passer Spans 47 in$ 575 No670 BDF1 FEhain-lailed spoatlier tar Coo 02 Pee Wee engine Spans 25 ing 225 No676 Filliner PC nainelentrin Orgo-coing Sport ship designed tar Shine Imp 30 nnotar Hen tricycle gear spans 40 ing 400 No O77TItoedorhItd CL StonIer tar 20-35 pooerTcoa plan sheetS dracon trap original 1982 Veca kit Spans 545g 6BeseBeo FFpoestCoastgostonanGotdoardesignSpanslOin8 150 No 676619 BIngol Large PC Spoosler spanogS 120-24 passer 2 plan sheets5 1700 No601 1969 Bade 604 FE Robber Scale model spans 105 in$ 325 Ne 684 Otaggerwlng Beneb 3-Channel PC Schaalyard-Soale Si-coins Sportster Far 049 passer Spann0 375 No606 Feller PC Panern-type spaS plane Far 2-ar 4-cycie passer Spans 65 in0 725 No606 Stealth Glider FE robberband-loonohed faandbalca Canard Catepolcotealth Glider cecoba Span0 200 No 66pmoenas Morse Ossoot SdC PC 15 scale biplane 50 oncoer Spans 63 3 plan sheets5 1575 Ne6923 Metorgeooter PC high pedonnannooailplane Spans 110 in2 plan sheets5 1150 No 696 Pole Cot FE P30 Class AMA Senior record holder Spans 31 in0 225 60697 Tlgerklttee 6 PC high performance 5pad Aenobatia design FOr 05115 Cobalt eleciric passer Spans 54 n$ 1000 No660TepCot60L-1 FE PobberFAl lndaorStiokGliderSoIdOAMA Cat FlOand Stick National Records Spans 13125 2 plan sheets$ 300 60760 Raedps 0150 PC economical cematile Span Trainer Ideal tar 10 passer Weighs 33-na Spans 50 in5 575 No701 Jompie Gee SC high performance Spanstar designed tartan fly ecents Weighs 3-lb spans 40 40-45 posse9 725 No702 Hainkel eE 16 FE Scale model 011524 German nranoplann Far CiLine Mini-6 geassd 01oct60 motor Spaes2a e$ 200 No703 Cleedhoppor PC Grant Scale 5padstor reminiscent iSSOs heath hosseborit Spans Shin Far 50 passer 2 plan sheets$ 1450 Ne 760 ZeeSh FEHand-Leonch Gliderfomserioos competition Wing OT Spans 18 35-3e grams5 200 No760 4-Geen PC lass coing 411-50-pacoered Sport Aerabatic desisa reminiscent 1930s Kinner Ryan span placa Spans 575 in$ 600 No707 02F Tracker CL Scale nssin-045-pocoerad model Grossman design Spans 35 in$ 325 No706 PGMTroieor FE vbbnrpocoemed trainer ideal tar introdootion ROD flying Spans lOin$ 150 NO760 AIr Cadet PC FE Ion flen/trainer 101020 passer Stick-amnd-tinnoe model reoolleots Cessna 0rd Gag opans 3805 400 No710 0010kb 360 RC Pylon racer Spas timer intermediate bonder//tiler Can racod coilS CL PC 20 power Foam coing spans 45 g 550 No711 Fokker 611 Type FE RGG Robber-pocoered Galdeer Stick model Rnmenmsnenf WWI German tIghter Spans 235 n$ 200 No712 Seletet Redi6aL-SOTP PC Spod Scale version Finnish yinke military trainer FonOoadraorZenoah power spans 04 2 plan sheets 5 1500 No713Mig29 FECatapolt Glider Patterned aher Rossian dnmonstraforflnssnatCleveland Ohio 1551 Spans 13 n$ 225 No754 Mod 000k PC acem-toendly Sport flier reloand aloco flight Eaoells loss sloss maneovers Far 25-30 paoer Spans 000 2 plan sheets0 500 No 710 Stephens hero PC Goader scale aerobatic plane spans 725 in. oses 75/90 passer Dylan sheets0 1375 No 716 Slow Poker FE Record-sethng tntdoonHLG spans 245 Wood stroct s meinfarcadssithcaonfihem200 No7l7onetlaeaoRCCawhat P1000 RCSparSCombattlierfrom Rossiator3Sooengine 3-channels spannd75-in0 575 Ne 716 Lito Bipe SC Onry aerobatic fan fly Sipa design 1050 Honfon Spans 665-in 103045 posse 2 plan 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52-in 2 plan sheets$ 1125 No 727 CortIs SF7C Seahawk CL Moihi-polpose bissinger C compete both Profile Scale Saw Carher Spans 32-in Far 35-40 passer$ 400 Ne 726 ElosIds SotellOc 450 FE Electric cenvession Can bout far 6-cell Class 07-cell Class Spans 56 r-n Fan Astroflife 035 Cobalt motor$ 725 No 72OTl6erCat PC Eiectnc73-n-span evolofian nI TigerKitten LococoingsportlaerobalictorCobaitwmotorand 261200 MASceils Dylansheets0 1400 No720 Seopper CL Profile stonIer boned ciannin 1504/cA Snapper 46/s-inspan roidoolog 25-35 power5 550 No731 Feothar Merehont FE Old-Tinner FE am PC Assist 72 spani25 passer Easy folly eaceptianaily wnde stall tolerance 2 plan sheets$ 1075 F Circle numbers plans wish order best hsndling please include requeSts payment tor some other service piano order No phone orderg call 703 435-0750 order assisfasce ONLYI II II II II II II II I_I II III Make check money order payable US funds drawn US bank ModelAviation AMA 1810 I Samuel Morse Dr Reston vA 22090 Please allow 3 6 weeks deliveryI Please print carefullyEnclosed $ _________________________________ NAMEAMA No STREETI II CITYI II STATEZIPI L.1 193262310314326332386447539578 588598603646650654661667674675 o 676677678679681684686688689692 O696697699700701702703705706707 708709710711712713714715716717 718719720721722723724725726727 728729730731732 92 Plan price includes first class postage US delivery Air Mail Over 300 miles orders non-US addresses please add $250 Air Mail postage handling plan 182 Model Aviation ncrease rubber weight shifts CC aft Again little concern model could important others Finally longer motor compared started will need braiding avoid CG shift between wound unwound big problem ignored either Questions welcome inued Letters Editor Continued page 167 water want predict failure will manifest itself What pressure will home builder actually maintain can violent rupture also very possible Such accident may never happen article AMA MA has become liable am guilty author wanting put seemingly useful throwaways use have air conditioning contractor life now work Lennox Industries Inc major manufacturer air conditioning equipment time used produce portable air tanks filling flat tires until recognized liability reusing cans began removing tank valves puncturing safety patch scroungers could use cans unsafe pressure applications second concern obvious open-belt drive Inexpensive covers available could made should have part article Enough obvious error Daniel D Kautz Piano Texas Possible am 15 years old have flying model airplanes about three years now After reading Letters Editor numerous times different issues MA decided send thoughts let other people see person age thinks about model aviation Anyway idea take tail section V tail attach wingtips normal plane would no need tail section control surfaces would V wing Up would normal V tail except both Vs would up position down would same Along needing tail section would no need ailerons roll simply make V go up other down banking climb raise V other Well thoughts 15-yearold very anxious see whether type design will work Derek Walton Port Neches Texas PS imagined plane have tricyclestyle landing gear pusher 9 03 0 -3ChJ 93 C C53 9 0 90 - w g-3 00 ccn 2 9s 530 C9 0 V 0 93 C 3 9 o 9d2 -53 9 53C 0 no. 00 039 C53 53 5393 90 - 0 930 -9 9 0 92115 0ChJ adO 6053 0 Co CUC 9 0 0 NE i 5 LLfl
Edition: Model Aviation - 1993/03
Page Numbers: 76, 179, 180, 182
IF REE FLIGHT THINK fun using rubber power choice numerous variables tailor power model propeller desired flight performance months column some intro ductory concepts may helpful yet expert rubber fliers Torque twisting force purposes discussion torque power energy same thing Torque easily measured torque plotted graph against turns curve results shown Figure 1 amount torque given number turns represents power point area under broken line graph represents total energy available apparent necessary approach maximum turns motor get full performance Most energy comes last 20% turns unwinding rubber has short powerful burst followed 2 0 eli 0 0 C C U eel C C OLD-TIMERS d drop-off power slowly diminishing power rapid change can cause serious trim problems especially certain types models factor can contribute sharp knee power curve type quality rubber Good purpose rubber has torque vs turns curve rather shallow concave curve poor rubber will tend have J shape sharp angle between cruise power initial burst power know power required particular model setup climb horizontal line can added graph energy above linethat area under torque curveis energy available climb remaining energy below horizontal line goes slow descent cruise apparent given motor lower airplane weight lowering horizontal line will shift total zjjjFigure 1 n Ci 0/ C Increasing turns Increased twisting forcetorqueplotted against increased turns rubber motor results upward curve shown area below dotted line represents total energy available motor Inferior rubber would give curve like dashed line energy climb Isnt wonderful education gives us ability explain obvious convenience let us use modern Wakefield explain next point provides fixed model weight/wing area/weight rubber situation 40 grams rubber Figure 2 shows approximate curves 40-gram motor arranged 16 8 4 strands -in strip have drawn hypothetical line climb power variable cross section motor since weight remains constant length motor varies Less cross section fewer strands results longer motor number turns possible also changes Turns per unit length varies cross section inverse fashion means smaller cross section turns per inch Since Continued page 179 76 Model Aviation ly informative entertaining highly recommended Dave Thornburgs new book Speak Model Airplane meaningful us models have important part lives Dave understands such treat visit someone does understand isnt Bill Bakers Earl Stahl-designed Skyfarer typical scale models has propeller diameter somewhat limited landing gear length will best long braided motor minimal cross section will produce some climb See text Figure 2 B C Increasing turns rubber motor Approximate curves 40-gram motor arranged 16 8 4 strands A-in strip Broken line represents climb power Variable cross section motor constant weight length varies Less cross section fewer strands results longer motor 1-.Custom Balsa Die Cutting2 Balsa Sheets745/16 X 14880104 1/8x 12x24613 753/8 x 1-/25194105 3/16x 12x24363 36 48 38 1/8x 1/413 18- 1 1/16 228 40 39 1/8 3/814 19176 1/2 x 279 105 106 1/4x 12x24420 XX.f76B107 3/32x12x481004 21/16x332 44 40 1/8x1/217 24- \76C 3 1/16x 4537141 3/16x 3/1613 ~1081/8x12x481149 4Balsa Blocks1093/16X 12x48726 3/32x2355042 3/16x3/817 216 121/4x12x48838 5 3/32 x 3395343 3/16 x 1/22231 6 3/32x4679244 1/4x1/4182777 1/sx262 112 110B 71/8 x 23854451/4 x 3/81930782 x 2 74 130 ilOC IEVRIOODS792 x 3 90149SpruceSticks 81/8 x 35069461/4 x 1/220 34D JEVV803 x 3 1192253648 91/8x477104471/4x3/43445 813 x 4 1602991111/8 x 1/81723 103/16 x 24462481/4 x 14360 ustom Cut Balsa1121/8x 1/42128 113/16 x 35879495/16 x 5/162432 Quality Prices 81B1131/8 x 3/82333 123/16 x 491121503/8 x 3/827 42AAA Quality Ecuadorian Balsa 81C1143/16x3/162939 131/4 x 25172513/8 x 1/23153 Sanded Close Tolerances Balsa Planks361151/4 x 1/43652 141/4x37093523/8x3/44863 1285 N Union Street821x21571161/4x3/84158 151/4 x 4110134533/8 x 16573 Stockton CA 9520583lx 32191171/4 x 1/24766 165/16x26082541/2x 1/241 55841x42931181/4x 16789 175/16 x 382110551/2 x 3/453711 209-464-0180852x22311195/16 x 5/164362 185/16 x 4139185561/2 x 16487862x 33351205/16 x 1/24875 193/8x26895575/8x5/85472 E C L872x44751215/16x3/46789 203/8 x 390128583/3 x 3/47598883 x 35151223/8 x 3/85264 213/8x 4165230593/4 x 184111 ace Lite Ply893x47151233/8x 1/26381 221/2 x 283116601 x 1104139 Low Cost Door Skin 8981241/2 x 1/26992 231/2 x 3 109 155 608torButkheads& FuselageSides 89C1251/2 7101 241/2X 4 230 268 60C1/8x6x48 125 y Light 1258 248118x 12x48 225901/8x6x24 115 125C 24CBalsaTapered911/8x 12x24173 BassSticks AileronStock BUS Hours 800-500 PST M-F921/8 x 24 x 243453648 BalsaSticks3648We accept VISA MasterCard931/8x 6x 481731263/16 x 3/162837 261/16x 1/163648611/4 x 143 Checks & COD 94 1/8x 12x48 345 127 3/16 x 1/4 24 30 0611611/4 x 1-/450 70 ping Handling $500 95 1/4x6x24 201 128 3/16 x 3/8 31 38 271/16 x 1/80914621/4 x 1- 1/57 82 COD add $450 96 1/4 x 12 x 24 259 129 3/16 x 1/2 37 46 631/4 90 nimum Order $2500 97 1/4 x 6 x 48 259 130 3/16 x 3/4 48 60 281/16 x 3/161016 litornia Residents98x 12x485181311/4 x 1/43442 291/16 x 1/41018645/16 x 1/259 84 301/16 x 3/81120655/16 94 dd 6h% Sales Tas 988 132 1/4 x 3/8 39 49 311/16x 1/214 24 66 3/8x 1/2659298C133 1/4x3/46480 134 3/8x3/84860 323/32 x 3/3207 11 67 3/8 x 274 105BalsaPly Birch135 3/8 x 1/256 70 333/32x1/80914683/8x2/284122 TrailingEdge993/32x6x122531363/8x3/47290 343/32x1/41318691/2X 1/28011536481001/8x6x123111371/2x 1/27290 353/32x3/81419701/2x290125711/8x 1/218311013/16x6x122191381/2x3/496120 363/32x 1/2 17 24 708723/16x 3/42950 102 1/4x6x 12 242 1388 371/8 x 1/8 09 13 70C731/4 x 13661 103 3/32x 12x24 503 138C Contact Us Kitting Needs FF Duration/Murphy Continued page 176 circuit battery Because feel bit ridiculous running across grassy fields WPAFB nice sunny days lights have headlamp circuit Road riding different story its simple task ride along flip switch necessary Hank also compliments Honda folks electronic design feature automatically kicks booster coil triples charging rate headlamps turned Also generator designed match normal battery drain bike use way no regulator required system Well anyway Roy Rogers always said Happy trails thanks Hank info See ya downwind ylon/Hager Continued page 162 go good fiberglass supply house buy some resin dye will match color cockpit interior black case will prevent visible white line inside canopy white microballoon-and-epoxy mixture attached canopy Make sure work fillet lines pleasing Once get close dip finger water run along fillet will smooth out epoxy try make perfect well sandpaper 23 Once fillet dry sand contour pleasing Fill depressed areas DAP Vinyl Spackle hardware store easier work apply epoxy sands much easier replace slow-cure epoxy spackle because no strength spackle know have heen tempted because easy work hut aint no free lunches 24 Now stand back congratulate yourself first-rate job paint airplane concerned getting scratches canopy sanding fuselage can removed progressively finer grits sandpaper up 2000-grit spray clear topcoat airplane tiny scratches will just go away canopy will look like molded fuselage Good Luck ld-Timer/Baker Continued paqe 76 nature gives us no free lunch what give up get turns torque per turn varies directly cross section long small cross-section motor gives long slow run rather subdued burst what desired indoor flying outdoor scale models Such motor might also best certain Old-Timer sport duration models will come back short 16-strand motor gives rapid climb may hard control trim because rapid changes power level model could near-vertical climb throttle chopped amount down side thrust required may excessive efficient use remaining power power can controllednote available energy goes climbthere isnt much cruise dont want sort power curve typical scale model typical scalelike Old-Timer sport model smallish stab center gravity 30% chord model designed taskthat has large lifting stabilizer permits center-of-gravity 60% further aft will able use motor power curve similar 16-strand example good results actual modern Wakefield practice March 1993 179 4000 diflerent22000 3-view drawings color FOTO-PAAKSincluding KOkU-FAN Antiques Military Civilian Helicopters Sailpianes Catalog/Guide $500Overseas $1006 TJLTIMATESPORT RC I205 East Asktend/PO Boo 727/Soda Springs Idoko 93276 agegoc tn-stet3995d73742FsrCurherlnln Send SAsE usable range power 10 16 strands equivalent 20 32 strands /s thickness rubber varies somewhat too length rubber given number strands constant total weight may vary may see series rear peg holes Wakefields Coupes have fixed rules rubber weight flying competitively models no weight rule rubber such SAM Old-Timer events Mulvihill found helped made motors constant length thickness rubber varied adjusted number strands weight near constant kept models trim little center-of-gravity shift power change motors changed example standard motor Lanzo 1940 Stick 34-in length 85 90 grams number strands varied 30 34 /s depending thickness rubber kept number strands constant cross section varied Therefore power level shape torque curve varied affected trim Affecting trim almost always bad real world modem Wakefield flying usable motors run about 16 10 strands een 14 gives rapid rather short runs needed climb average rather windy conditions 10 12 range gives longer slower climb desired early morning dead-air BILL EFFINGER5 SAYS Only PIann Pat1ern Sets grce assorted designs want have selected hest classic designs stall hors yea choose troer patterns pat jmpotant ecdusioe teats 9/3ScetecSssn5 170 l4d org span 90 ngth pain ont areaS sin RC 22 Cli engines 17 los RC3S-5 9~Cessna 170 RC6S-5$149S 9/3 Seat MONOCOUPE 90A 128 srgnpanh2 Ia h2liOsqrn wing area Fon20 35010 e nor RC3S-4 9/3 Scale PIPER TRI-PACER PA22 1 1h-/ wing span 2390 sq reng area 20 1i 010 engines 4-5 ci SIC approc n2Ibs Or- sacrall lengli RC3S-3 9/3 Scat PIPER CUB J-3 l1-9nirg span 90 lerglhOhOOsq wing arts ass ac 2i 1030010 engines RC3S-2 rounds dead-air performance reflects efficient use power under ideal conditions weather during average contest day shorter faster run will likely better expenditure power controlled some extent propeller addition converting torque thrust functions air brake control rate energy release general rubber models best large propellers 25% moreeven 50% wingspan excessive means 12-in propeller 24-in model might look funny could fly well scale models scalelike Old-Timer sport duration models landing gear length puts limits propeller diameter best choice long motor limited cross section type torque curve Let get specific casemy AceWhitman Albatross small cabintype ship about 30-in span Pharis kit provides plastic P-30-type propeller 9-in diameter plans show balsa propeller 11-in diameter plastic propeller too low pitch liking As have explained previous columns plastic rubber model props seem run about 08 10 pitch/diameter ratio too low believe line propellers 125 P/D ratio produced would money bank Anyway decided fly model first plastic propeller 9/4 Scale ALBATROS DVa 99 eingspan72-/ leegnh2572nq wing area t3- 23 010 engines 405 lhlCn2 Es RCOS-1 7$2400 9/4 Scale SE5A gg10 wingspan 222g pa neng area 791022 engines RCOS-7S24a 9/4 SCale SPAD C-XIII 79rIe wIng span 2120 sq etrg area 13 31 engrnet Capable llyer captures innaginatne RCOS-8 9/4 SC$t FOKKER DR-i TRIPLANE 72 aeng span n7725g snng anea.79 100 engtror ROOS-6 9/4 SCale SOPWITH CAMEL F1 ha veng span illO sq wing area1I en Sb RIG Flpreord 9 SolId sonst ROOS-1 1 9/4 Scale FOKKER 0-ViI 99 wingspan 2220 sq wing area 90 1o2SClD engine 35 oh 11 En RCQS-5S24at first motor ten strands 3A6-inwide 24-in long model has lifting stabilizer felt would handle CG about 50% did add about 1/2 oz lead nose sticking sheet reinforcement insideout sight Wow Too much power exciting first few seconds went eight strands 24-in long about 3/oo down right thrust trimmed model climbed rapidly made smooth transition power glide glide acceptable satisfied because wanted longer slower climb what enjoy watching end several choices open to get what wanted could keep same propeller same motor remake fewer strands greater length advantage would would keep total weight center gravity same lower-crosssection motor greater length would give longer slower run Possibly six strands would just right lets say would give too little time-of-climb power model would land before winds half spent other hand could add strands back eight againbut keep new length would increase cross section torque giving greater climb would also increase total weight model problem because model light might need increase ballast center-of-gravity adjustment Most motor aft 114 S NIEUPORT28 80r/ wing span- 1660 sq wing area 78 23 OlD engine 4 cli RIO 11 lbs RCQS-1 8 $24 115 Scat FAIRCHILD 24 145wngspanSchR/C 22to 35 OlD engine appros 17 lbs less RIO radii & inline ye sons RO3S-6 $3455 119 Scat FAIRCHILD 24 72-/ wing span 5 engines RO6S-6$14se * Prices complete plans sub assembly & detailed parts lists PLEASE ADD $300 shIppIng mailIng tube New Plan Sets brochure $100 WE TECHNICAL SERVICES Sea Island GA 31561-0246 180 Model Aviation 4Ce~ Recognised @ GSA CertifiedAedesoe F lie NoFile No..j Ps E26226LR25154 tt5 Only certitied Checks meney orders accepted Minimum order 91400 lenthree packages 094 Poorerpoles 9490 per peckage * 9299 shipping handlingl CT residents add sales nan Pices subiect change notice DEAIER INQUIRIES INVITED luthet infonmenion dna er pt cos send SASS Business Cad no SERMOS R/C SNAP CONNECTORS Inc Cedar Corners Station Box 16787 Stamford CT 06905 12031 322-6294 roern nycgsurteses AlunrLendingGear CleenCencpyoceilekle guildersKitS2n5 Sheeedhit93b5 OnlannShoeredllirgaOg FULL-SIZE PLANS 732 Long-Wing ARIA$475 Wing plan ARIA #719 Sept 92 MA designed Bill Winter 99-in span 63-oz Variable flap system Compared short wing Aria has increased LID lower sink rate flatter turns Aggressive soarer Forgiving nice fly trainer 10-6 11-6 folding prop Four channels 1 plan sheet No 193 StIletto CL Stool model McDonald nnnner 1976 1580 1962 FAI World Chanrpn$ 375 No262 Croshnoster CL crash-prool rome Tcoosjzos1S/SSand 35/4Spoooer$ 125 No3101930 Fleel Blylsee PC Spon Scale 35/40 posset nod 4-channel Sponn 56 1/5 scale 2 plan sheets$ 025 No 314 Oroke II PC Ken Willard s hying boat ton 3-channel 15 ponoer Fly fonn lend osith removable sean$ 375 No 326 Taylor Cob RC Don Srull s Schoolyani Scala 10045 ponhen 2-3 channel Spann 50 in$ 350 No 332 Zephyr RC semall 2-channel Glider tam hand-loonch taco thernnal am siope nooring$ 200 No 306 Loser 200 PC Sport Scale replica channpionshiy Aerobatic lion FordS posse 45 channol an sheets0 1075 No 447 112A Miss Anrerleos PC Old Tcner 1/28 Tenaca model 1am 045 51050 2channols0 650 No 539 Siedt0r Slow-Motion 10 PC Taillesstlying ooing ton 15 passer Spans 60 3 channel0 350 No578 Oehwoloor 1266 PC Goader-scale Sailplane Spans 125 2 plan Sheets5 1475 No301 Gee Bee Model Y PC Golden Age Racer Spans 72-in 15 scale tar 60 passes 3 plan sheets$ 1175 No 009 Mortob PC Slepe-Soaring Salplane Spans 41 in. 2 PC channels0 425 Ne 096 Coronet 100 PCAasst Sid-Tinne enlarged 150% Spans 72 FOr 40- 4-strakeI30- 2-etlake0 650 No603 Sparrow Idasek P30 FE Coerpetition robber-pacoen plane voon 1907 NaIn Spans 3D in0 225 No 646 WIntee Howk FE Robber-passer Cooped Hicet contpntitioo plane Spans 47 in$ 375 No606 4760 BC Opeelol PC Aenobatic sped plane 10140 pooser Spans Olin 3 pIne sheets$ 1075 No 604 Torsenot RCTrainer/Spadsterstyledaherthe F14 Spano6o Far 40/61 passer 4 plan sheet5 1525 No 661 Etttbry-Onotie FE Enrbrya End orance robber passer plane Spans 205 in$ 200 No667 AT4 CL Senriscale profile Stonten tar 35140 passer Spans 47 in$ 575 No670 BDF1 FEhain-lailed spoatlier tar Coo 02 Pee Wee engine Spans 25 ing 225 No676 Filliner PC nainelentrin Orgo-coing Sport ship designed tar Shine Imp 30 nnotar Hen tricycle gear spans 40 ing 400 No O77TItoedorhItd CL StonIer tar 20-35 pooerTcoa plan sheetS dracon trap original 1982 Veca kit Spans 545g 6BeseBeo FFpoestCoastgostonanGotdoardesignSpanslOin8 150 No 676619 BIngol Large PC Spoosler spanogS 120-24 passer 2 plan sheets5 1700 No601 1969 Bade 604 FE Robber Scale model spans 105 in$ 325 Ne 684 Otaggerwlng Beneb 3-Channel PC Schaalyard-Soale Si-coins Sportster Far 049 passer Spann0 375 No606 Feller PC Panern-type spaS plane Far 2-ar 4-cycie passer Spans 65 in0 725 No606 Stealth Glider FE robberband-loonohed faandbalca Canard Catepolcotealth Glider cecoba Span0 200 No 66pmoenas Morse Ossoot SdC PC 15 scale biplane 50 oncoer Spans 63 3 plan sheets5 1575 Ne6923 Metorgeooter PC high pedonnannooailplane Spans 110 in2 plan sheets5 1150 No 696 Pole Cot FE P30 Class AMA Senior record holder Spans 31 in0 225 60697 Tlgerklttee 6 PC high performance 5pad Aenobatia design FOr 05115 Cobalt eleciric passer Spans 54 n$ 1000 No660TepCot60L-1 FE PobberFAl lndaorStiokGliderSoIdOAMA Cat FlOand Stick National Records Spans 13125 2 plan sheets$ 300 60760 Raedps 0150 PC economical cematile Span Trainer Ideal tar 10 passer Weighs 33-na Spans 50 in5 575 No701 Jompie Gee SC high performance Spanstar designed tartan fly ecents Weighs 3-lb spans 40 40-45 posse9 725 No702 Hainkel eE 16 FE Scale model 011524 German nranoplann Far CiLine Mini-6 geassd 01oct60 motor Spaes2a e$ 200 No703 Cleedhoppor PC Grant Scale 5padstor reminiscent iSSOs heath hosseborit Spans Shin Far 50 passer 2 plan sheets$ 1450 Ne 760 ZeeSh FEHand-Leonch Gliderfomserioos competition Wing OT Spans 18 35-3e grams5 200 No760 4-Geen PC lass coing 411-50-pacoered Sport Aerabatic desisa reminiscent 1930s Kinner Ryan span placa Spans 575 in$ 600 No707 02F Tracker CL Scale nssin-045-pocoerad model Grossman design Spans 35 in$ 325 No706 PGMTroieor FE vbbnrpocoemed trainer ideal tar introdootion ROD flying Spans lOin$ 150 NO760 AIr Cadet PC FE Ion flen/trainer 101020 passer Stick-amnd-tinnoe model reoolleots Cessna 0rd Gag opans 3805 400 No710 0010kb 360 RC Pylon racer Spas timer intermediate bonder//tiler Can racod coilS CL PC 20 power Foam coing spans 45 g 550 No711 Fokker 611 Type FE RGG Robber-pocoered Galdeer Stick model Rnmenmsnenf WWI German tIghter Spans 235 n$ 200 No712 Seletet Redi6aL-SOTP PC Spod Scale version Finnish yinke military trainer FonOoadraorZenoah power spans 04 2 plan sheets 5 1500 No713Mig29 FECatapolt Glider Patterned aher Rossian dnmonstraforflnssnatCleveland Ohio 1551 Spans 13 n$ 225 No754 Mod 000k PC acem-toendly Sport flier reloand aloco flight Eaoells loss sloss maneovers Far 25-30 paoer Spans 000 2 plan sheets0 500 No 710 Stephens hero PC Goader scale aerobatic plane spans 725 in. oses 75/90 passer Dylan sheets0 1375 No 716 Slow Poker FE Record-sethng tntdoonHLG spans 245 Wood stroct s meinfarcadssithcaonfihem200 No7l7onetlaeaoRCCawhat P1000 RCSparSCombattlierfrom Rossiator3Sooengine 3-channels spannd75-in0 575 Ne 716 Lito Bipe SC Onry aerobatic fan fly Sipa design 1050 Honfon Spans 665-in 103045 posse 2 plan sheets5 600 No719 Aria PC Eiectrio pedoecance/spart Girder Far 56 direct- dove motor F nor ohanneis Spans 65 Seeable Sap sestem 2 plan sheets5 725 No72OMlnalewan FE FrankZalos popotaraii-baisa-oovered robben-possemed madeitakenfram PapalarScience Jane 1041 SpansDO in$ 200 Ne 721 Lil Feller PC mid-coins ton fly sport piann Folly aernbntio 4-channel 000101 40-51 passer Spans 450 650 NO733 Laaep Mets FE Doohied 70-sq-in Iron 04ntvnian design Far Mini-6 motarand 50 mAS batfemies Spans 15/5 225 Ne 723 Aalo 67 CL Designed Eviand Fiat Zossada Ada Poanan intended Short Aerobatice Program Fo 15 passer 5pans 36/a-in$ 400 No 724 Sonret Weapon PC Gianf Scale mid-ssiog aerabatlo ship taken original 1947 Slant design Spans aO-in 2 plan sheets$ 1600 No 725 Cordisel 69 CL Stonter coith niassic 1 SSSs linas 0100124 Stool ships eon assarded 20 appearanoe paints Spans 62/n-in 60 posse$ 1125 No 726 Cle-5hDee PC EieoOo-passered ight-sseight Cessna look-alike Ish flyer designed 035 motor 6-cod pack spans 52-in 2 plan sheets$ 1125 No 727 CortIs SF7C Seahawk CL Moihi-polpose bissinger C compete both Profile Scale Saw Carher Spans 32-in Far 35-40 passer$ 400 Ne 726 ElosIds SotellOc 450 FE Electric cenvession Can bout far 6-cell Class 07-cell Class Spans 56 r-n Fan Astroflife 035 Cobalt motor$ 725 No 72OTl6erCat PC Eiectnc73-n-span evolofian nI TigerKitten LococoingsportlaerobalictorCobaitwmotorand 261200 MASceils Dylansheets0 1400 No720 Seopper CL Profile stonIer boned ciannin 1504/cA Snapper 46/s-inspan roidoolog 25-35 power5 550 No731 Feothar Merehont FE Old-Tinner FE am PC Assist 72 spani25 passer Easy folly eaceptianaily wnde stall tolerance 2 plan sheets$ 1075 F Circle numbers plans wish order best hsndling please include requeSts payment tor some other service piano order No phone orderg call 703 435-0750 order assisfasce ONLYI II II II II II II II I_I II III Make check money order payable US funds drawn US bank ModelAviation AMA 1810 I Samuel Morse Dr Reston vA 22090 Please allow 3 6 weeks deliveryI Please print carefullyEnclosed $ _________________________________ NAMEAMA No STREETI II CITYI II STATEZIPI L.1 193262310314326332386447539578 588598603646650654661667674675 o 676677678679681684686688689692 O696697699700701702703705706707 708709710711712713714715716717 718719720721722723724725726727 728729730731732 92 Plan price includes first class postage US delivery Air Mail Over 300 miles orders non-US addresses please add $250 Air Mail postage handling plan 182 Model Aviation ncrease rubber weight shifts CC aft Again little concern model could important others Finally longer motor compared started will need braiding avoid CG shift between wound unwound big problem ignored either Questions welcome inued Letters Editor Continued page 167 water want predict failure will manifest itself What pressure will home builder actually maintain can violent rupture also very possible Such accident may never happen article AMA MA has become liable am guilty author wanting put seemingly useful throwaways use have air conditioning contractor life now work Lennox Industries Inc major manufacturer air conditioning equipment time used produce portable air tanks filling flat tires until recognized liability reusing cans began removing tank valves puncturing safety patch scroungers could use cans unsafe pressure applications second concern obvious open-belt drive Inexpensive covers available could made should have part article Enough obvious error Daniel D Kautz Piano Texas Possible am 15 years old have flying model airplanes about three years now After reading Letters Editor numerous times different issues MA decided send thoughts let other people see person age thinks about model aviation Anyway idea take tail section V tail attach wingtips normal plane would no need tail section control surfaces would V wing Up would normal V tail except both Vs would up position down would same Along needing tail section would no need ailerons roll simply make V go up other down banking climb raise V other Well thoughts 15-yearold very anxious see whether type design will work Derek Walton Port Neches Texas PS imagined plane have tricyclestyle landing gear pusher 9 03 0 -3ChJ 93 C C53 9 0 90 - w g-3 00 ccn 2 9s 530 C9 0 V 0 93 C 3 9 o 9d2 -53 9 53C 0 no. 00 039 C53 53 5393 90 - 0 930 -9 9 0 92115 0ChJ adO 6053 0 Co CUC 9 0 0 NE i 5 LLfl
Edition: Model Aviation - 1993/03
Page Numbers: 76, 179, 180, 182
IF REE FLIGHT THINK fun using rubber power choice numerous variables tailor power model propeller desired flight performance months column some intro ductory concepts may helpful yet expert rubber fliers Torque twisting force purposes discussion torque power energy same thing Torque easily measured torque plotted graph against turns curve results shown Figure 1 amount torque given number turns represents power point area under broken line graph represents total energy available apparent necessary approach maximum turns motor get full performance Most energy comes last 20% turns unwinding rubber has short powerful burst followed 2 0 eli 0 0 C C U eel C C OLD-TIMERS d drop-off power slowly diminishing power rapid change can cause serious trim problems especially certain types models factor can contribute sharp knee power curve type quality rubber Good purpose rubber has torque vs turns curve rather shallow concave curve poor rubber will tend have J shape sharp angle between cruise power initial burst power know power required particular model setup climb horizontal line can added graph energy above linethat area under torque curveis energy available climb remaining energy below horizontal line goes slow descent cruise apparent given motor lower airplane weight lowering horizontal line will shift total zjjjFigure 1 n Ci 0/ C Increasing turns Increased twisting forcetorqueplotted against increased turns rubber motor results upward curve shown area below dotted line represents total energy available motor Inferior rubber would give curve like dashed line energy climb Isnt wonderful education gives us ability explain obvious convenience let us use modern Wakefield explain next point provides fixed model weight/wing area/weight rubber situation 40 grams rubber Figure 2 shows approximate curves 40-gram motor arranged 16 8 4 strands -in strip have drawn hypothetical line climb power variable cross section motor since weight remains constant length motor varies Less cross section fewer strands results longer motor number turns possible also changes Turns per unit length varies cross section inverse fashion means smaller cross section turns per inch Since Continued page 179 76 Model Aviation ly informative entertaining highly recommended Dave Thornburgs new book Speak Model Airplane meaningful us models have important part lives Dave understands such treat visit someone does understand isnt Bill Bakers Earl Stahl-designed Skyfarer typical scale models has propeller diameter somewhat limited landing gear length will best long braided motor minimal cross section will produce some climb See text Figure 2 B C Increasing turns rubber motor Approximate curves 40-gram motor arranged 16 8 4 strands A-in strip Broken line represents climb power Variable cross section motor constant weight length varies Less cross section fewer strands results longer motor 1-.Custom Balsa Die Cutting2 Balsa Sheets745/16 X 14880104 1/8x 12x24613 753/8 x 1-/25194105 3/16x 12x24363 36 48 38 1/8x 1/413 18- 1 1/16 228 40 39 1/8 3/814 19176 1/2 x 279 105 106 1/4x 12x24420 XX.f76B107 3/32x12x481004 21/16x332 44 40 1/8x1/217 24- \76C 3 1/16x 4537141 3/16x 3/1613 ~1081/8x12x481149 4Balsa Blocks1093/16X 12x48726 3/32x2355042 3/16x3/817 216 121/4x12x48838 5 3/32 x 3395343 3/16 x 1/22231 6 3/32x4679244 1/4x1/4182777 1/sx262 112 110B 71/8 x 23854451/4 x 3/81930782 x 2 74 130 ilOC IEVRIOODS792 x 3 90149SpruceSticks 81/8 x 35069461/4 x 1/220 34D JEVV803 x 3 1192253648 91/8x477104471/4x3/43445 813 x 4 1602991111/8 x 1/81723 103/16 x 24462481/4 x 14360 ustom Cut Balsa1121/8x 1/42128 113/16 x 35879495/16 x 5/162432 Quality Prices 81B1131/8 x 3/82333 123/16 x 491121503/8 x 3/827 42AAA Quality Ecuadorian Balsa 81C1143/16x3/162939 131/4 x 25172513/8 x 1/23153 Sanded Close Tolerances Balsa Planks361151/4 x 1/43652 141/4x37093523/8x3/44863 1285 N Union Street821x21571161/4x3/84158 151/4 x 4110134533/8 x 16573 Stockton CA 9520583lx 32191171/4 x 1/24766 165/16x26082541/2x 1/241 55841x42931181/4x 16789 175/16 x 382110551/2 x 3/453711 209-464-0180852x22311195/16 x 5/164362 185/16 x 4139185561/2 x 16487862x 33351205/16 x 1/24875 193/8x26895575/8x5/85472 E C L872x44751215/16x3/46789 203/8 x 390128583/3 x 3/47598883 x 35151223/8 x 3/85264 213/8x 4165230593/4 x 184111 ace Lite Ply893x47151233/8x 1/26381 221/2 x 283116601 x 1104139 Low Cost Door Skin 8981241/2 x 1/26992 231/2 x 3 109 155 608torButkheads& FuselageSides 89C1251/2 7101 241/2X 4 230 268 60C1/8x6x48 125 y Light 1258 248118x 12x48 225901/8x6x24 115 125C 24CBalsaTapered911/8x 12x24173 BassSticks AileronStock BUS Hours 800-500 PST M-F921/8 x 24 x 243453648 BalsaSticks3648We accept VISA MasterCard931/8x 6x 481731263/16 x 3/162837 261/16x 1/163648611/4 x 143 Checks & COD 94 1/8x 12x48 345 127 3/16 x 1/4 24 30 0611611/4 x 1-/450 70 ping Handling $500 95 1/4x6x24 201 128 3/16 x 3/8 31 38 271/16 x 1/80914621/4 x 1- 1/57 82 COD add $450 96 1/4 x 12 x 24 259 129 3/16 x 1/2 37 46 631/4 90 nimum Order $2500 97 1/4 x 6 x 48 259 130 3/16 x 3/4 48 60 281/16 x 3/161016 litornia Residents98x 12x485181311/4 x 1/43442 291/16 x 1/41018645/16 x 1/259 84 301/16 x 3/81120655/16 94 dd 6h% Sales Tas 988 132 1/4 x 3/8 39 49 311/16x 1/214 24 66 3/8x 1/2659298C133 1/4x3/46480 134 3/8x3/84860 323/32 x 3/3207 11 67 3/8 x 274 105BalsaPly Birch135 3/8 x 1/256 70 333/32x1/80914683/8x2/284122 TrailingEdge993/32x6x122531363/8x3/47290 343/32x1/41318691/2X 1/28011536481001/8x6x123111371/2x 1/27290 353/32x3/81419701/2x290125711/8x 1/218311013/16x6x122191381/2x3/496120 363/32x 1/2 17 24 708723/16x 3/42950 102 1/4x6x 12 242 1388 371/8 x 1/8 09 13 70C731/4 x 13661 103 3/32x 12x24 503 138C Contact Us Kitting Needs FF Duration/Murphy Continued page 176 circuit battery Because feel bit ridiculous running across grassy fields WPAFB nice sunny days lights have headlamp circuit Road riding different story its simple task ride along flip switch necessary Hank also compliments Honda folks electronic design feature automatically kicks booster coil triples charging rate headlamps turned Also generator designed match normal battery drain bike use way no regulator required system Well anyway Roy Rogers always said Happy trails thanks Hank info See ya downwind ylon/Hager Continued page 162 go good fiberglass supply house buy some resin dye will match color cockpit interior black case will prevent visible white line inside canopy white microballoon-and-epoxy mixture attached canopy Make sure work fillet lines pleasing Once get close dip finger water run along fillet will smooth out epoxy try make perfect well sandpaper 23 Once fillet dry sand contour pleasing Fill depressed areas DAP Vinyl Spackle hardware store easier work apply epoxy sands much easier replace slow-cure epoxy spackle because no strength spackle know have heen tempted because easy work hut aint no free lunches 24 Now stand back congratulate yourself first-rate job paint airplane concerned getting scratches canopy sanding fuselage can removed progressively finer grits sandpaper up 2000-grit spray clear topcoat airplane tiny scratches will just go away canopy will look like molded fuselage Good Luck ld-Timer/Baker Continued paqe 76 nature gives us no free lunch what give up get turns torque per turn varies directly cross section long small cross-section motor gives long slow run rather subdued burst what desired indoor flying outdoor scale models Such motor might also best certain Old-Timer sport duration models will come back short 16-strand motor gives rapid climb may hard control trim because rapid changes power level model could near-vertical climb throttle chopped amount down side thrust required may excessive efficient use remaining power power can controllednote available energy goes climbthere isnt much cruise dont want sort power curve typical scale model typical scalelike Old-Timer sport model smallish stab center gravity 30% chord model designed taskthat has large lifting stabilizer permits center-of-gravity 60% further aft will able use motor power curve similar 16-strand example good results actual modern Wakefield practice March 1993 179 4000 diflerent22000 3-view drawings color FOTO-PAAKSincluding KOkU-FAN Antiques Military Civilian Helicopters Sailpianes Catalog/Guide $500Overseas $1006 TJLTIMATESPORT RC I205 East Asktend/PO Boo 727/Soda Springs Idoko 93276 agegoc tn-stet3995d73742FsrCurherlnln Send SAsE usable range power 10 16 strands equivalent 20 32 strands /s thickness rubber varies somewhat too length rubber given number strands constant total weight may vary may see series rear peg holes Wakefields Coupes have fixed rules rubber weight flying competitively models no weight rule rubber such SAM Old-Timer events Mulvihill found helped made motors constant length thickness rubber varied adjusted number strands weight near constant kept models trim little center-of-gravity shift power change motors changed example standard motor Lanzo 1940 Stick 34-in length 85 90 grams number strands varied 30 34 /s depending thickness rubber kept number strands constant cross section varied Therefore power level shape torque curve varied affected trim Affecting trim almost always bad real world modem Wakefield flying usable motors run about 16 10 strands een 14 gives rapid rather short runs needed climb average rather windy conditions 10 12 range gives longer slower climb desired early morning dead-air BILL EFFINGER5 SAYS Only PIann Pat1ern Sets grce assorted designs want have selected hest classic designs stall hors yea choose troer patterns pat jmpotant ecdusioe teats 9/3ScetecSssn5 170 l4d org span 90 ngth pain ont areaS sin RC 22 Cli engines 17 los RC3S-5 9~Cessna 170 RC6S-5$149S 9/3 Seat MONOCOUPE 90A 128 srgnpanh2 Ia h2liOsqrn wing area Fon20 35010 e nor RC3S-4 9/3 Scale PIPER TRI-PACER PA22 1 1h-/ wing span 2390 sq reng area 20 1i 010 engines 4-5 ci SIC approc n2Ibs Or- sacrall lengli RC3S-3 9/3 Scat PIPER CUB J-3 l1-9nirg span 90 lerglhOhOOsq wing arts ass ac 2i 1030010 engines RC3S-2 rounds dead-air performance reflects efficient use power under ideal conditions weather during average contest day shorter faster run will likely better expenditure power controlled some extent propeller addition converting torque thrust functions air brake control rate energy release general rubber models best large propellers 25% moreeven 50% wingspan excessive means 12-in propeller 24-in model might look funny could fly well scale models scalelike Old-Timer sport duration models landing gear length puts limits propeller diameter best choice long motor limited cross section type torque curve Let get specific casemy AceWhitman Albatross small cabintype ship about 30-in span Pharis kit provides plastic P-30-type propeller 9-in diameter plans show balsa propeller 11-in diameter plastic propeller too low pitch liking As have explained previous columns plastic rubber model props seem run about 08 10 pitch/diameter ratio too low believe line propellers 125 P/D ratio produced would money bank Anyway decided fly model first plastic propeller 9/4 Scale ALBATROS DVa 99 eingspan72-/ leegnh2572nq wing area t3- 23 010 engines 405 lhlCn2 Es RCOS-1 7$2400 9/4 Scale SE5A gg10 wingspan 222g pa neng area 791022 engines RCOS-7S24a 9/4 SCale SPAD C-XIII 79rIe wIng span 2120 sq etrg area 13 31 engrnet Capable llyer captures innaginatne RCOS-8 9/4 SC$t FOKKER DR-i TRIPLANE 72 aeng span n7725g snng anea.79 100 engtror ROOS-6 9/4 SCale SOPWITH CAMEL F1 ha veng span illO sq wing area1I en Sb RIG Flpreord 9 SolId sonst ROOS-1 1 9/4 Scale FOKKER 0-ViI 99 wingspan 2220 sq wing area 90 1o2SClD engine 35 oh 11 En RCQS-5S24at first motor ten strands 3A6-inwide 24-in long model has lifting stabilizer felt would handle CG about 50% did add about 1/2 oz lead nose sticking sheet reinforcement insideout sight Wow Too much power exciting first few seconds went eight strands 24-in long about 3/oo down right thrust trimmed model climbed rapidly made smooth transition power glide glide acceptable satisfied because wanted longer slower climb what enjoy watching end several choices open to get what wanted could keep same propeller same motor remake fewer strands greater length advantage would would keep total weight center gravity same lower-crosssection motor greater length would give longer slower run Possibly six strands would just right lets say would give too little time-of-climb power model would land before winds half spent other hand could add strands back eight againbut keep new length would increase cross section torque giving greater climb would also increase total weight model problem because model light might need increase ballast center-of-gravity adjustment Most motor aft 114 S NIEUPORT28 80r/ wing span- 1660 sq wing area 78 23 OlD engine 4 cli RIO 11 lbs RCQS-1 8 $24 115 Scat FAIRCHILD 24 145wngspanSchR/C 22to 35 OlD engine appros 17 lbs less RIO radii & inline ye sons RO3S-6 $3455 119 Scat FAIRCHILD 24 72-/ wing span 5 engines RO6S-6$14se * Prices complete plans sub assembly & detailed parts lists PLEASE ADD $300 shIppIng mailIng tube New Plan Sets brochure $100 WE TECHNICAL SERVICES Sea Island GA 31561-0246 180 Model Aviation 4Ce~ Recognised @ GSA CertifiedAedesoe F lie NoFile No..j Ps E26226LR25154 tt5 Only certitied Checks meney orders accepted Minimum order 91400 lenthree packages 094 Poorerpoles 9490 per peckage * 9299 shipping handlingl CT residents add sales nan Pices subiect change notice DEAIER INQUIRIES INVITED luthet infonmenion dna er pt cos send SASS Business Cad no SERMOS R/C SNAP CONNECTORS Inc Cedar Corners Station Box 16787 Stamford CT 06905 12031 322-6294 roern nycgsurteses AlunrLendingGear CleenCencpyoceilekle guildersKitS2n5 Sheeedhit93b5 OnlannShoeredllirgaOg FULL-SIZE PLANS 732 Long-Wing ARIA$475 Wing plan ARIA #719 Sept 92 MA designed Bill Winter 99-in span 63-oz Variable flap system Compared short wing Aria has increased LID lower sink rate flatter turns Aggressive soarer Forgiving nice fly trainer 10-6 11-6 folding prop Four channels 1 plan sheet No 193 StIletto CL Stool model McDonald nnnner 1976 1580 1962 FAI World Chanrpn$ 375 No262 Croshnoster CL crash-prool rome Tcoosjzos1S/SSand 35/4Spoooer$ 125 No3101930 Fleel Blylsee PC Spon Scale 35/40 posset nod 4-channel Sponn 56 1/5 scale 2 plan sheets$ 025 No 314 Oroke II PC Ken Willard s hying boat ton 3-channel 15 ponoer Fly fonn lend osith removable sean$ 375 No 326 Taylor Cob RC Don Srull s Schoolyani Scala 10045 ponhen 2-3 channel Spann 50 in$ 350 No 332 Zephyr RC semall 2-channel Glider tam hand-loonch taco thernnal am siope nooring$ 200 No 306 Loser 200 PC Sport Scale replica channpionshiy Aerobatic lion FordS posse 45 channol an sheets0 1075 No 447 112A Miss Anrerleos PC Old Tcner 1/28 Tenaca model 1am 045 51050 2channols0 650 No 539 Siedt0r Slow-Motion 10 PC Taillesstlying ooing ton 15 passer Spans 60 3 channel0 350 No578 Oehwoloor 1266 PC Goader-scale Sailplane Spans 125 2 plan Sheets5 1475 No301 Gee Bee Model Y PC Golden Age Racer Spans 72-in 15 scale tar 60 passes 3 plan sheets$ 1175 No 009 Mortob PC Slepe-Soaring Salplane Spans 41 in. 2 PC channels0 425 Ne 096 Coronet 100 PCAasst Sid-Tinne enlarged 150% Spans 72 FOr 40- 4-strakeI30- 2-etlake0 650 No603 Sparrow Idasek P30 FE Coerpetition robber-pacoen plane voon 1907 NaIn Spans 3D in0 225 No 646 WIntee Howk FE Robber-passer Cooped Hicet contpntitioo plane Spans 47 in$ 375 No606 4760 BC Opeelol PC Aenobatic sped plane 10140 pooser Spans Olin 3 pIne sheets$ 1075 No 604 Torsenot RCTrainer/Spadsterstyledaherthe F14 Spano6o Far 40/61 passer 4 plan sheet5 1525 No 661 Etttbry-Onotie FE Enrbrya End orance robber passer plane Spans 205 in$ 200 No667 AT4 CL Senriscale profile Stonten tar 35140 passer Spans 47 in$ 575 No670 BDF1 FEhain-lailed spoatlier tar Coo 02 Pee Wee engine Spans 25 ing 225 No676 Filliner PC nainelentrin Orgo-coing Sport ship designed tar Shine Imp 30 nnotar Hen tricycle gear spans 40 ing 400 No O77TItoedorhItd CL StonIer tar 20-35 pooerTcoa plan sheetS dracon trap original 1982 Veca kit Spans 545g 6BeseBeo FFpoestCoastgostonanGotdoardesignSpanslOin8 150 No 676619 BIngol Large PC Spoosler spanogS 120-24 passer 2 plan sheets5 1700 No601 1969 Bade 604 FE Robber Scale model spans 105 in$ 325 Ne 684 Otaggerwlng Beneb 3-Channel PC Schaalyard-Soale Si-coins Sportster Far 049 passer Spann0 375 No606 Feller PC Panern-type spaS plane Far 2-ar 4-cycie passer Spans 65 in0 725 No606 Stealth Glider FE robberband-loonohed faandbalca Canard Catepolcotealth Glider cecoba Span0 200 No 66pmoenas Morse Ossoot SdC PC 15 scale biplane 50 oncoer Spans 63 3 plan sheets5 1575 Ne6923 Metorgeooter PC high pedonnannooailplane Spans 110 in2 plan sheets5 1150 No 696 Pole Cot FE P30 Class AMA Senior record holder Spans 31 in0 225 60697 Tlgerklttee 6 PC high performance 5pad Aenobatia design FOr 05115 Cobalt eleciric passer Spans 54 n$ 1000 No660TepCot60L-1 FE PobberFAl lndaorStiokGliderSoIdOAMA Cat FlOand Stick National Records Spans 13125 2 plan sheets$ 300 60760 Raedps 0150 PC economical cematile Span Trainer Ideal tar 10 passer Weighs 33-na Spans 50 in5 575 No701 Jompie Gee SC high performance Spanstar designed tartan fly ecents Weighs 3-lb spans 40 40-45 posse9 725 No702 Hainkel eE 16 FE Scale model 011524 German nranoplann Far CiLine Mini-6 geassd 01oct60 motor Spaes2a e$ 200 No703 Cleedhoppor PC Grant Scale 5padstor reminiscent iSSOs heath hosseborit Spans Shin Far 50 passer 2 plan sheets$ 1450 Ne 760 ZeeSh FEHand-Leonch Gliderfomserioos competition Wing OT Spans 18 35-3e grams5 200 No760 4-Geen PC lass coing 411-50-pacoered Sport Aerabatic desisa reminiscent 1930s Kinner Ryan span placa Spans 575 in$ 600 No707 02F Tracker CL Scale nssin-045-pocoerad model Grossman design Spans 35 in$ 325 No706 PGMTroieor FE vbbnrpocoemed trainer ideal tar introdootion ROD flying Spans lOin$ 150 NO760 AIr Cadet PC FE Ion flen/trainer 101020 passer Stick-amnd-tinnoe model reoolleots Cessna 0rd Gag opans 3805 400 No710 0010kb 360 RC Pylon racer Spas timer intermediate bonder//tiler Can racod coilS CL PC 20 power Foam coing spans 45 g 550 No711 Fokker 611 Type FE RGG Robber-pocoered Galdeer Stick model Rnmenmsnenf WWI German tIghter Spans 235 n$ 200 No712 Seletet Redi6aL-SOTP PC Spod Scale version Finnish yinke military trainer FonOoadraorZenoah power spans 04 2 plan sheets 5 1500 No713Mig29 FECatapolt Glider Patterned aher Rossian dnmonstraforflnssnatCleveland Ohio 1551 Spans 13 n$ 225 No754 Mod 000k PC acem-toendly Sport flier reloand aloco flight Eaoells loss sloss maneovers Far 25-30 paoer Spans 000 2 plan sheets0 500 No 710 Stephens hero PC Goader scale aerobatic plane spans 725 in. oses 75/90 passer Dylan sheets0 1375 No 716 Slow Poker FE Record-sethng tntdoonHLG spans 245 Wood stroct s meinfarcadssithcaonfihem200 No7l7onetlaeaoRCCawhat P1000 RCSparSCombattlierfrom Rossiator3Sooengine 3-channels spannd75-in0 575 Ne 716 Lito Bipe SC Onry aerobatic fan fly Sipa design 1050 Honfon Spans 665-in 103045 posse 2 plan sheets5 600 No719 Aria PC Eiectrio pedoecance/spart Girder Far 56 direct- dove motor F nor ohanneis Spans 65 Seeable Sap sestem 2 plan sheets5 725 No72OMlnalewan FE FrankZalos popotaraii-baisa-oovered robben-possemed madeitakenfram PapalarScience Jane 1041 SpansDO in$ 200 Ne 721 Lil Feller PC mid-coins ton fly sport piann Folly aernbntio 4-channel 000101 40-51 passer Spans 450 650 NO733 Laaep Mets FE Doohied 70-sq-in Iron 04ntvnian design Far Mini-6 motarand 50 mAS batfemies Spans 15/5 225 Ne 723 Aalo 67 CL Designed Eviand Fiat Zossada Ada Poanan intended Short Aerobatice Program Fo 15 passer 5pans 36/a-in$ 400 No 724 Sonret Weapon PC Gianf Scale mid-ssiog aerabatlo ship taken original 1947 Slant design Spans aO-in 2 plan sheets$ 1600 No 725 Cordisel 69 CL Stonter coith niassic 1 SSSs linas 0100124 Stool ships eon assarded 20 appearanoe paints Spans 62/n-in 60 posse$ 1125 No 726 Cle-5hDee PC EieoOo-passered ight-sseight Cessna look-alike Ish flyer designed 035 motor 6-cod pack spans 52-in 2 plan sheets$ 1125 No 727 CortIs SF7C Seahawk CL Moihi-polpose bissinger C compete both Profile Scale Saw Carher Spans 32-in Far 35-40 passer$ 400 Ne 726 ElosIds SotellOc 450 FE Electric cenvession Can bout far 6-cell Class 07-cell Class Spans 56 r-n Fan Astroflife 035 Cobalt motor$ 725 No 72OTl6erCat PC Eiectnc73-n-span evolofian nI TigerKitten LococoingsportlaerobalictorCobaitwmotorand 261200 MASceils Dylansheets0 1400 No720 Seopper CL Profile stonIer boned ciannin 1504/cA Snapper 46/s-inspan roidoolog 25-35 power5 550 No731 Feothar Merehont FE Old-Tinner FE am PC Assist 72 spani25 passer Easy folly eaceptianaily wnde stall tolerance 2 plan sheets$ 1075 F Circle numbers plans wish order best hsndling please include requeSts payment tor some other service piano order No phone orderg call 703 435-0750 order assisfasce ONLYI II II II II II II II I_I II III Make check money order payable US funds drawn US bank ModelAviation AMA 1810 I Samuel Morse Dr Reston vA 22090 Please allow 3 6 weeks deliveryI Please print carefullyEnclosed $ _________________________________ NAMEAMA No STREETI II CITYI II STATEZIPI L.1 193262310314326332386447539578 588598603646650654661667674675 o 676677678679681684686688689692 O696697699700701702703705706707 708709710711712713714715716717 718719720721722723724725726727 728729730731732 92 Plan price includes first class postage US delivery Air Mail Over 300 miles orders non-US addresses please add $250 Air Mail postage handling plan 182 Model Aviation ncrease rubber weight shifts CC aft Again little concern model could important others Finally longer motor compared started will need braiding avoid CG shift between wound unwound big problem ignored either Questions welcome inued Letters Editor Continued page 167 water want predict failure will manifest itself What pressure will home builder actually maintain can violent rupture also very possible Such accident may never happen article AMA MA has become liable am guilty author wanting put seemingly useful throwaways use have air conditioning contractor life now work Lennox Industries Inc major manufacturer air conditioning equipment time used produce portable air tanks filling flat tires until recognized liability reusing cans began removing tank valves puncturing safety patch scroungers could use cans unsafe pressure applications second concern obvious open-belt drive Inexpensive covers available could made should have part article Enough obvious error Daniel D Kautz Piano Texas Possible am 15 years old have flying model airplanes about three years now After reading Letters Editor numerous times different issues MA decided send thoughts let other people see person age thinks about model aviation Anyway idea take tail section V tail attach wingtips normal plane would no need tail section control surfaces would V wing Up would normal V tail except both Vs would up position down would same Along needing tail section would no need ailerons roll simply make V go up other down banking climb raise V other Well thoughts 15-yearold very anxious see whether type design will work Derek Walton Port Neches Texas PS imagined plane have tricyclestyle landing gear pusher 9 03 0 -3ChJ 93 C C53 9 0 90 - w g-3 00 ccn 2 9s 530 C9 0 V 0 93 C 3 9 o 9d2 -53 9 53C 0 no. 00 039 C53 53 5393 90 - 0 930 -9 9 0 92115 0ChJ adO 6053 0 Co CUC 9 0 0 NE i 5 LLfl
Edition: Model Aviation - 1993/03
Page Numbers: 76, 179, 180, 182
IF REE FLIGHT THINK fun using rubber power choice numerous variables tailor power model propeller desired flight performance months column some intro ductory concepts may helpful yet expert rubber fliers Torque twisting force purposes discussion torque power energy same thing Torque easily measured torque plotted graph against turns curve results shown Figure 1 amount torque given number turns represents power point area under broken line graph represents total energy available apparent necessary approach maximum turns motor get full performance Most energy comes last 20% turns unwinding rubber has short powerful burst followed 2 0 eli 0 0 C C U eel C C OLD-TIMERS d drop-off power slowly diminishing power rapid change can cause serious trim problems especially certain types models factor can contribute sharp knee power curve type quality rubber Good purpose rubber has torque vs turns curve rather shallow concave curve poor rubber will tend have J shape sharp angle between cruise power initial burst power know power required particular model setup climb horizontal line can added graph energy above linethat area under torque curveis energy available climb remaining energy below horizontal line goes slow descent cruise apparent given motor lower airplane weight lowering horizontal line will shift total zjjjFigure 1 n Ci 0/ C Increasing turns Increased twisting forcetorqueplotted against increased turns rubber motor results upward curve shown area below dotted line represents total energy available motor Inferior rubber would give curve like dashed line energy climb Isnt wonderful education gives us ability explain obvious convenience let us use modern Wakefield explain next point provides fixed model weight/wing area/weight rubber situation 40 grams rubber Figure 2 shows approximate curves 40-gram motor arranged 16 8 4 strands -in strip have drawn hypothetical line climb power variable cross section motor since weight remains constant length motor varies Less cross section fewer strands results longer motor number turns possible also changes Turns per unit length varies cross section inverse fashion means smaller cross section turns per inch Since Continued page 179 76 Model Aviation ly informative entertaining highly recommended Dave Thornburgs new book Speak Model Airplane meaningful us models have important part lives Dave understands such treat visit someone does understand isnt Bill Bakers Earl Stahl-designed Skyfarer typical scale models has propeller diameter somewhat limited landing gear length will best long braided motor minimal cross section will produce some climb See text Figure 2 B C Increasing turns rubber motor Approximate curves 40-gram motor arranged 16 8 4 strands A-in strip Broken line represents climb power Variable cross section motor constant weight length varies Less cross section fewer strands results longer motor 1-.Custom Balsa Die Cutting2 Balsa Sheets745/16 X 14880104 1/8x 12x24613 753/8 x 1-/25194105 3/16x 12x24363 36 48 38 1/8x 1/413 18- 1 1/16 228 40 39 1/8 3/814 19176 1/2 x 279 105 106 1/4x 12x24420 XX.f76B107 3/32x12x481004 21/16x332 44 40 1/8x1/217 24- \76C 3 1/16x 4537141 3/16x 3/1613 ~1081/8x12x481149 4Balsa Blocks1093/16X 12x48726 3/32x2355042 3/16x3/817 216 121/4x12x48838 5 3/32 x 3395343 3/16 x 1/22231 6 3/32x4679244 1/4x1/4182777 1/sx262 112 110B 71/8 x 23854451/4 x 3/81930782 x 2 74 130 ilOC IEVRIOODS792 x 3 90149SpruceSticks 81/8 x 35069461/4 x 1/220 34D JEVV803 x 3 1192253648 91/8x477104471/4x3/43445 813 x 4 1602991111/8 x 1/81723 103/16 x 24462481/4 x 14360 ustom Cut Balsa1121/8x 1/42128 113/16 x 35879495/16 x 5/162432 Quality Prices 81B1131/8 x 3/82333 123/16 x 491121503/8 x 3/827 42AAA Quality Ecuadorian Balsa 81C1143/16x3/162939 131/4 x 25172513/8 x 1/23153 Sanded Close Tolerances Balsa Planks361151/4 x 1/43652 141/4x37093523/8x3/44863 1285 N Union Street821x21571161/4x3/84158 151/4 x 4110134533/8 x 16573 Stockton CA 9520583lx 32191171/4 x 1/24766 165/16x26082541/2x 1/241 55841x42931181/4x 16789 175/16 x 382110551/2 x 3/453711 209-464-0180852x22311195/16 x 5/164362 185/16 x 4139185561/2 x 16487862x 33351205/16 x 1/24875 193/8x26895575/8x5/85472 E C L872x44751215/16x3/46789 203/8 x 390128583/3 x 3/47598883 x 35151223/8 x 3/85264 213/8x 4165230593/4 x 184111 ace Lite Ply893x47151233/8x 1/26381 221/2 x 283116601 x 1104139 Low Cost Door Skin 8981241/2 x 1/26992 231/2 x 3 109 155 608torButkheads& FuselageSides 89C1251/2 7101 241/2X 4 230 268 60C1/8x6x48 125 y Light 1258 248118x 12x48 225901/8x6x24 115 125C 24CBalsaTapered911/8x 12x24173 BassSticks AileronStock BUS Hours 800-500 PST M-F921/8 x 24 x 243453648 BalsaSticks3648We accept VISA MasterCard931/8x 6x 481731263/16 x 3/162837 261/16x 1/163648611/4 x 143 Checks & COD 94 1/8x 12x48 345 127 3/16 x 1/4 24 30 0611611/4 x 1-/450 70 ping Handling $500 95 1/4x6x24 201 128 3/16 x 3/8 31 38 271/16 x 1/80914621/4 x 1- 1/57 82 COD add $450 96 1/4 x 12 x 24 259 129 3/16 x 1/2 37 46 631/4 90 nimum Order $2500 97 1/4 x 6 x 48 259 130 3/16 x 3/4 48 60 281/16 x 3/161016 litornia Residents98x 12x485181311/4 x 1/43442 291/16 x 1/41018645/16 x 1/259 84 301/16 x 3/81120655/16 94 dd 6h% Sales Tas 988 132 1/4 x 3/8 39 49 311/16x 1/214 24 66 3/8x 1/2659298C133 1/4x3/46480 134 3/8x3/84860 323/32 x 3/3207 11 67 3/8 x 274 105BalsaPly Birch135 3/8 x 1/256 70 333/32x1/80914683/8x2/284122 TrailingEdge993/32x6x122531363/8x3/47290 343/32x1/41318691/2X 1/28011536481001/8x6x123111371/2x 1/27290 353/32x3/81419701/2x290125711/8x 1/218311013/16x6x122191381/2x3/496120 363/32x 1/2 17 24 708723/16x 3/42950 102 1/4x6x 12 242 1388 371/8 x 1/8 09 13 70C731/4 x 13661 103 3/32x 12x24 503 138C Contact Us Kitting Needs FF Duration/Murphy Continued page 176 circuit battery Because feel bit ridiculous running across grassy fields WPAFB nice sunny days lights have headlamp circuit Road riding different story its simple task ride along flip switch necessary Hank also compliments Honda folks electronic design feature automatically kicks booster coil triples charging rate headlamps turned Also generator designed match normal battery drain bike use way no regulator required system Well anyway Roy Rogers always said Happy trails thanks Hank info See ya downwind ylon/Hager Continued page 162 go good fiberglass supply house buy some resin dye will match color cockpit interior black case will prevent visible white line inside canopy white microballoon-and-epoxy mixture attached canopy Make sure work fillet lines pleasing Once get close dip finger water run along fillet will smooth out epoxy try make perfect well sandpaper 23 Once fillet dry sand contour pleasing Fill depressed areas DAP Vinyl Spackle hardware store easier work apply epoxy sands much easier replace slow-cure epoxy spackle because no strength spackle know have heen tempted because easy work hut aint no free lunches 24 Now stand back congratulate yourself first-rate job paint airplane concerned getting scratches canopy sanding fuselage can removed progressively finer grits sandpaper up 2000-grit spray clear topcoat airplane tiny scratches will just go away canopy will look like molded fuselage Good Luck ld-Timer/Baker Continued paqe 76 nature gives us no free lunch what give up get turns torque per turn varies directly cross section long small cross-section motor gives long slow run rather subdued burst what desired indoor flying outdoor scale models Such motor might also best certain Old-Timer sport duration models will come back short 16-strand motor gives rapid climb may hard control trim because rapid changes power level model could near-vertical climb throttle chopped amount down side thrust required may excessive efficient use remaining power power can controllednote available energy goes climbthere isnt much cruise dont want sort power curve typical scale model typical scalelike Old-Timer sport model smallish stab center gravity 30% chord model designed taskthat has large lifting stabilizer permits center-of-gravity 60% further aft will able use motor power curve similar 16-strand example good results actual modern Wakefield practice March 1993 179 4000 diflerent22000 3-view drawings color FOTO-PAAKSincluding KOkU-FAN Antiques Military Civilian Helicopters Sailpianes Catalog/Guide $500Overseas $1006 TJLTIMATESPORT RC I205 East Asktend/PO Boo 727/Soda Springs Idoko 93276 agegoc tn-stet3995d73742FsrCurherlnln Send SAsE usable range power 10 16 strands equivalent 20 32 strands /s thickness rubber varies somewhat too length rubber given number strands constant total weight may vary may see series rear peg holes Wakefields Coupes have fixed rules rubber weight flying competitively models no weight rule rubber such SAM Old-Timer events Mulvihill found helped made motors constant length thickness rubber varied adjusted number strands weight near constant kept models trim little center-of-gravity shift power change motors changed example standard motor Lanzo 1940 Stick 34-in length 85 90 grams number strands varied 30 34 /s depending thickness rubber kept number strands constant cross section varied Therefore power level shape torque curve varied affected trim Affecting trim almost always bad real world modem Wakefield flying usable motors run about 16 10 strands een 14 gives rapid rather short runs needed climb average rather windy conditions 10 12 range gives longer slower climb desired early morning dead-air BILL EFFINGER5 SAYS Only PIann Pat1ern Sets grce assorted designs want have selected hest classic designs stall hors yea choose troer patterns pat jmpotant ecdusioe teats 9/3ScetecSssn5 170 l4d org span 90 ngth pain ont areaS sin RC 22 Cli engines 17 los RC3S-5 9~Cessna 170 RC6S-5$149S 9/3 Seat MONOCOUPE 90A 128 srgnpanh2 Ia h2liOsqrn wing area Fon20 35010 e nor RC3S-4 9/3 Scale PIPER TRI-PACER PA22 1 1h-/ wing span 2390 sq reng area 20 1i 010 engines 4-5 ci SIC approc n2Ibs Or- sacrall lengli RC3S-3 9/3 Scat PIPER CUB J-3 l1-9nirg span 90 lerglhOhOOsq wing arts ass ac 2i 1030010 engines RC3S-2 rounds dead-air performance reflects efficient use power under ideal conditions weather during average contest day shorter faster run will likely better expenditure power controlled some extent propeller addition converting torque thrust functions air brake control rate energy release general rubber models best large propellers 25% moreeven 50% wingspan excessive means 12-in propeller 24-in model might look funny could fly well scale models scalelike Old-Timer sport duration models landing gear length puts limits propeller diameter best choice long motor limited cross section type torque curve Let get specific casemy AceWhitman Albatross small cabintype ship about 30-in span Pharis kit provides plastic P-30-type propeller 9-in diameter plans show balsa propeller 11-in diameter plastic propeller too low pitch liking As have explained previous columns plastic rubber model props seem run about 08 10 pitch/diameter ratio too low believe line propellers 125 P/D ratio produced would money bank Anyway decided fly model first plastic propeller 9/4 Scale ALBATROS DVa 99 eingspan72-/ leegnh2572nq wing area t3- 23 010 engines 405 lhlCn2 Es RCOS-1 7$2400 9/4 Scale SE5A gg10 wingspan 222g pa neng area 791022 engines RCOS-7S24a 9/4 SCale SPAD C-XIII 79rIe wIng span 2120 sq etrg area 13 31 engrnet Capable llyer captures innaginatne RCOS-8 9/4 SC$t FOKKER DR-i TRIPLANE 72 aeng span n7725g snng anea.79 100 engtror ROOS-6 9/4 SCale SOPWITH CAMEL F1 ha veng span illO sq wing area1I en Sb RIG Flpreord 9 SolId sonst ROOS-1 1 9/4 Scale FOKKER 0-ViI 99 wingspan 2220 sq wing area 90 1o2SClD engine 35 oh 11 En RCQS-5S24at first motor ten strands 3A6-inwide 24-in long model has lifting stabilizer felt would handle CG about 50% did add about 1/2 oz lead nose sticking sheet reinforcement insideout sight Wow Too much power exciting first few seconds went eight strands 24-in long about 3/oo down right thrust trimmed model climbed rapidly made smooth transition power glide glide acceptable satisfied because wanted longer slower climb what enjoy watching end several choices open to get what wanted could keep same propeller same motor remake fewer strands greater length advantage would would keep total weight center gravity same lower-crosssection motor greater length would give longer slower run Possibly six strands would just right lets say would give too little time-of-climb power model would land before winds half spent other hand could add strands back eight againbut keep new length would increase cross section torque giving greater climb would also increase total weight model problem because model light might need increase ballast center-of-gravity adjustment Most motor aft 114 S NIEUPORT28 80r/ wing span- 1660 sq wing area 78 23 OlD engine 4 cli RIO 11 lbs RCQS-1 8 $24 115 Scat FAIRCHILD 24 145wngspanSchR/C 22to 35 OlD engine appros 17 lbs less RIO radii & inline ye sons RO3S-6 $3455 119 Scat FAIRCHILD 24 72-/ wing span 5 engines RO6S-6$14se * Prices complete plans sub assembly & detailed parts lists PLEASE ADD $300 shIppIng mailIng tube New Plan Sets brochure $100 WE TECHNICAL SERVICES Sea Island GA 31561-0246 180 Model Aviation 4Ce~ Recognised @ GSA CertifiedAedesoe F lie NoFile No..j Ps E26226LR25154 tt5 Only certitied Checks meney orders accepted Minimum order 91400 lenthree packages 094 Poorerpoles 9490 per peckage * 9299 shipping handlingl CT residents add sales nan Pices subiect change notice DEAIER INQUIRIES INVITED luthet infonmenion dna er pt cos send SASS Business Cad no SERMOS R/C SNAP CONNECTORS Inc Cedar Corners Station Box 16787 Stamford CT 06905 12031 322-6294 roern nycgsurteses AlunrLendingGear CleenCencpyoceilekle guildersKitS2n5 Sheeedhit93b5 OnlannShoeredllirgaOg FULL-SIZE PLANS 732 Long-Wing ARIA$475 Wing plan ARIA #719 Sept 92 MA designed Bill Winter 99-in span 63-oz Variable flap system Compared short wing Aria has increased LID lower sink rate flatter turns Aggressive soarer Forgiving nice fly trainer 10-6 11-6 folding prop Four channels 1 plan sheet No 193 StIletto CL Stool model McDonald nnnner 1976 1580 1962 FAI World Chanrpn$ 375 No262 Croshnoster CL crash-prool rome Tcoosjzos1S/SSand 35/4Spoooer$ 125 No3101930 Fleel Blylsee PC Spon Scale 35/40 posset nod 4-channel Sponn 56 1/5 scale 2 plan sheets$ 025 No 314 Oroke II PC Ken Willard s hying boat ton 3-channel 15 ponoer Fly fonn lend osith removable sean$ 375 No 326 Taylor Cob RC Don Srull s Schoolyani Scala 10045 ponhen 2-3 channel Spann 50 in$ 350 No 332 Zephyr RC semall 2-channel Glider tam hand-loonch taco thernnal am siope nooring$ 200 No 306 Loser 200 PC Sport Scale replica channpionshiy Aerobatic lion FordS posse 45 channol an sheets0 1075 No 447 112A Miss Anrerleos PC Old Tcner 1/28 Tenaca model 1am 045 51050 2channols0 650 No 539 Siedt0r Slow-Motion 10 PC Taillesstlying ooing ton 15 passer Spans 60 3 channel0 350 No578 Oehwoloor 1266 PC Goader-scale Sailplane Spans 125 2 plan Sheets5 1475 No301 Gee Bee Model Y PC Golden Age Racer Spans 72-in 15 scale tar 60 passes 3 plan sheets$ 1175 No 009 Mortob PC Slepe-Soaring Salplane Spans 41 in. 2 PC channels0 425 Ne 096 Coronet 100 PCAasst Sid-Tinne enlarged 150% Spans 72 FOr 40- 4-strakeI30- 2-etlake0 650 No603 Sparrow Idasek P30 FE Coerpetition robber-pacoen plane voon 1907 NaIn Spans 3D in0 225 No 646 WIntee Howk FE Robber-passer Cooped Hicet contpntitioo plane Spans 47 in$ 375 No606 4760 BC Opeelol PC Aenobatic sped plane 10140 pooser Spans Olin 3 pIne sheets$ 1075 No 604 Torsenot RCTrainer/Spadsterstyledaherthe F14 Spano6o Far 40/61 passer 4 plan sheet5 1525 No 661 Etttbry-Onotie FE Enrbrya End orance robber passer plane Spans 205 in$ 200 No667 AT4 CL Senriscale profile Stonten tar 35140 passer Spans 47 in$ 575 No670 BDF1 FEhain-lailed spoatlier tar Coo 02 Pee Wee engine Spans 25 ing 225 No676 Filliner PC nainelentrin Orgo-coing Sport ship designed tar Shine Imp 30 nnotar Hen tricycle gear spans 40 ing 400 No O77TItoedorhItd CL StonIer tar 20-35 pooerTcoa plan sheetS dracon trap original 1982 Veca kit Spans 545g 6BeseBeo FFpoestCoastgostonanGotdoardesignSpanslOin8 150 No 676619 BIngol Large PC Spoosler spanogS 120-24 passer 2 plan sheets5 1700 No601 1969 Bade 604 FE Robber Scale model spans 105 in$ 325 Ne 684 Otaggerwlng Beneb 3-Channel PC Schaalyard-Soale Si-coins Sportster Far 049 passer Spann0 375 No606 Feller PC Panern-type spaS plane Far 2-ar 4-cycie passer Spans 65 in0 725 No606 Stealth Glider FE robberband-loonohed faandbalca Canard Catepolcotealth Glider cecoba Span0 200 No 66pmoenas Morse Ossoot SdC PC 15 scale biplane 50 oncoer Spans 63 3 plan sheets5 1575 Ne6923 Metorgeooter PC high pedonnannooailplane Spans 110 in2 plan sheets5 1150 No 696 Pole Cot FE P30 Class AMA Senior record holder Spans 31 in0 225 60697 Tlgerklttee 6 PC high performance 5pad Aenobatia design FOr 05115 Cobalt eleciric passer Spans 54 n$ 1000 No660TepCot60L-1 FE PobberFAl lndaorStiokGliderSoIdOAMA Cat FlOand Stick National Records Spans 13125 2 plan sheets$ 300 60760 Raedps 0150 PC economical cematile Span Trainer Ideal tar 10 passer Weighs 33-na Spans 50 in5 575 No701 Jompie Gee SC high performance Spanstar designed tartan fly ecents Weighs 3-lb spans 40 40-45 posse9 725 No702 Hainkel eE 16 FE Scale model 011524 German nranoplann Far CiLine Mini-6 geassd 01oct60 motor Spaes2a e$ 200 No703 Cleedhoppor PC Grant Scale 5padstor reminiscent iSSOs heath hosseborit Spans Shin Far 50 passer 2 plan sheets$ 1450 Ne 760 ZeeSh FEHand-Leonch Gliderfomserioos competition Wing OT Spans 18 35-3e grams5 200 No760 4-Geen PC lass coing 411-50-pacoered Sport Aerabatic desisa reminiscent 1930s Kinner Ryan span placa Spans 575 in$ 600 No707 02F Tracker CL Scale nssin-045-pocoerad model Grossman design Spans 35 in$ 325 No706 PGMTroieor FE vbbnrpocoemed trainer ideal tar introdootion ROD flying Spans lOin$ 150 NO760 AIr Cadet PC FE Ion flen/trainer 101020 passer Stick-amnd-tinnoe model reoolleots Cessna 0rd Gag opans 3805 400 No710 0010kb 360 RC Pylon racer Spas timer intermediate bonder//tiler Can racod coilS CL PC 20 power Foam coing spans 45 g 550 No711 Fokker 611 Type FE RGG Robber-pocoered Galdeer Stick model Rnmenmsnenf WWI German tIghter Spans 235 n$ 200 No712 Seletet Redi6aL-SOTP PC Spod Scale version Finnish yinke military trainer FonOoadraorZenoah power spans 04 2 plan sheets 5 1500 No713Mig29 FECatapolt Glider Patterned aher Rossian dnmonstraforflnssnatCleveland Ohio 1551 Spans 13 n$ 225 No754 Mod 000k PC acem-toendly Sport flier reloand aloco flight Eaoells loss sloss maneovers Far 25-30 paoer Spans 000 2 plan sheets0 500 No 710 Stephens hero PC Goader scale aerobatic plane spans 725 in. oses 75/90 passer Dylan sheets0 1375 No 716 Slow Poker FE Record-sethng tntdoonHLG spans 245 Wood stroct s meinfarcadssithcaonfihem200 No7l7onetlaeaoRCCawhat P1000 RCSparSCombattlierfrom Rossiator3Sooengine 3-channels spannd75-in0 575 Ne 716 Lito Bipe SC Onry aerobatic fan fly Sipa design 1050 Honfon Spans 665-in 103045 posse 2 plan sheets5 600 No719 Aria PC Eiectrio pedoecance/spart Girder Far 56 direct- dove motor F nor ohanneis Spans 65 Seeable Sap sestem 2 plan sheets5 725 No72OMlnalewan FE FrankZalos popotaraii-baisa-oovered robben-possemed madeitakenfram PapalarScience Jane 1041 SpansDO in$ 200 Ne 721 Lil Feller PC mid-coins ton fly sport piann Folly aernbntio 4-channel 000101 40-51 passer Spans 450 650 NO733 Laaep Mets FE Doohied 70-sq-in Iron 04ntvnian design Far Mini-6 motarand 50 mAS batfemies Spans 15/5 225 Ne 723 Aalo 67 CL Designed Eviand Fiat Zossada Ada Poanan intended Short Aerobatice Program Fo 15 passer 5pans 36/a-in$ 400 No 724 Sonret Weapon PC Gianf Scale mid-ssiog aerabatlo ship taken original 1947 Slant design Spans aO-in 2 plan sheets$ 1600 No 725 Cordisel 69 CL Stonter coith niassic 1 SSSs linas 0100124 Stool ships eon assarded 20 appearanoe paints Spans 62/n-in 60 posse$ 1125 No 726 Cle-5hDee PC EieoOo-passered ight-sseight Cessna look-alike Ish flyer designed 035 motor 6-cod pack spans 52-in 2 plan sheets$ 1125 No 727 CortIs SF7C Seahawk CL Moihi-polpose bissinger C compete both Profile Scale Saw Carher Spans 32-in Far 35-40 passer$ 400 Ne 726 ElosIds SotellOc 450 FE Electric cenvession Can bout far 6-cell Class 07-cell Class Spans 56 r-n Fan Astroflife 035 Cobalt motor$ 725 No 72OTl6erCat PC Eiectnc73-n-span evolofian nI TigerKitten LococoingsportlaerobalictorCobaitwmotorand 261200 MASceils Dylansheets0 1400 No720 Seopper CL Profile stonIer boned ciannin 1504/cA Snapper 46/s-inspan roidoolog 25-35 power5 550 No731 Feothar Merehont FE Old-Tinner FE am PC Assist 72 spani25 passer Easy folly eaceptianaily wnde stall tolerance 2 plan sheets$ 1075 F Circle numbers plans wish order best hsndling please include requeSts payment tor some other service piano order No phone orderg call 703 435-0750 order assisfasce ONLYI II II II II II II II I_I II III Make check money order payable US funds drawn US bank ModelAviation AMA 1810 I Samuel Morse Dr Reston vA 22090 Please allow 3 6 weeks deliveryI Please print carefullyEnclosed $ _________________________________ NAMEAMA No STREETI II CITYI II STATEZIPI L.1 193262310314326332386447539578 588598603646650654661667674675 o 676677678679681684686688689692 O696697699700701702703705706707 708709710711712713714715716717 718719720721722723724725726727 728729730731732 92 Plan price includes first class postage US delivery Air Mail Over 300 miles orders non-US addresses please add $250 Air Mail postage handling plan 182 Model Aviation ncrease rubber weight shifts CC aft Again little concern model could important others Finally longer motor compared started will need braiding avoid CG shift between wound unwound big problem ignored either Questions welcome inued Letters Editor Continued page 167 water want predict failure will manifest itself What pressure will home builder actually maintain can violent rupture also very possible Such accident may never happen article AMA MA has become liable am guilty author wanting put seemingly useful throwaways use have air conditioning contractor life now work Lennox Industries Inc major manufacturer air conditioning equipment time used produce portable air tanks filling flat tires until recognized liability reusing cans began removing tank valves puncturing safety patch scroungers could use cans unsafe pressure applications second concern obvious open-belt drive Inexpensive covers available could made should have part article Enough obvious error Daniel D Kautz Piano Texas Possible am 15 years old have flying model airplanes about three years now After reading Letters Editor numerous times different issues MA decided send thoughts let other people see person age thinks about model aviation Anyway idea take tail section V tail attach wingtips normal plane would no need tail section control surfaces would V wing Up would normal V tail except both Vs would up position down would same Along needing tail section would no need ailerons roll simply make V go up other down banking climb raise V other Well thoughts 15-yearold very anxious see whether type design will work Derek Walton Port Neches Texas PS imagined plane have tricyclestyle landing gear pusher 9 03 0 -3ChJ 93 C C53 9 0 90 - w g-3 00 ccn 2 9s 530 C9 0 V 0 93 C 3 9 o 9d2 -53 9 53C 0 no. 00 039 C53 53 5393 90 - 0 930 -9 9 0 92115 0ChJ adO 6053 0 Co CUC 9 0 0 NE i 5 LLfl