Radio Control: Giant Scale

Radio Control GIANT SCALE Bob Beckman IMAAS FOURTH ANNUAL Inter national Miniature Aircraft Associations Fourth Annual Fun Fly Festival moving West Coast year Location Sepulveda Basin Los Angeles dates Thursday August 16 through Sun day August 19 Giant Scalers Midwest especially East may disappointed location fair give Western big-birders chance would like quote paragraph notice received Don Godfrey will no full-scale air shows non-related events detract festival format relaxed enjoyable flying Giant Scale air craft Gate passes will required ever advance pilot registration well advance reservations picnic ban quet will mandatory Registrants required bring aircraft fly however registrants may bring aircraft wish fly static display Hurrah complete information write Don Godfrey 91 Blackstone Ave Binghamton NY 13903 Les Hard 2909 W Michigan Ave Lansing MI 48917 Walt Clark 5255-2 White Oak Ave Encino CA 91316 Quick Dirty Bill Wendt has de signing building Giant Scale aircraft since before started calling first met him Morgan Hill think 1979 first saw Fokker DVIII recently got letter some pictures thought worth passing Enclosed pictures design call Q/D Quick Dirty Fast easy build little dirty side aerodynamically Q/D actually basic structure A-scale scratch-built Citabria Pro shoulder wing 1500 sq inches strip ailerons Early year several weeks radio problems decided needed expendable airplane testing radios new repaired equipment Thus born Q/D picture shows wife Donna Q/D floats designed Ken Runestrand way fly during Ari zona summers unique features Q/D method attaching wing See picture wing being removed use -in ply braces secured permanently wing slip inside fuselage sides sembled secured sides 8-32 bolts inserted outside fuselage two braces fore aft side wing has one-in aluminum spar-tube serted hole -in ply braces during wing construction assures braces will separate wing construction survived recent poweron dive lake Q/D owned friend Scotty transmitter antenna extended Bill went say has plans avail able Q/D well DVIII several other designs reviewed Bills DVIII August 1981 column havent seen others assume up same high standard interested write W R Wendt 325 Buccaneer Lane Lake Havasu City AZ 86403 Wire sizes can safety matter re cently got letter Ralph Warner RAM Radio Controlled Models Inc 56 Model Aviation have ever wanted see models like Dario Brisighellas Starduster Too IMAA Fun Fly Festival place years FFF set Los Angeles August promises kind relaxed fun made 1981 event Louisville KY successful Left Isolating heavyduty servos receiver power supply can help avoid dreaded glitches column Right Heres battery/switch wiring isolated servo power setup previouslypublished drawing shows two slide switches Bob recommends heavierduty switch large battery anxious point out importance adequate wiring models especially large servos dont agree Ralphs numbers conclusions too obvious Giant Scalers dont understand potential problems associated large servos time us realize larger airframes mean larger loads control surfaces turn means need servos capable delivering power surfaces Keep mind servo doesnt produce power simply device controlled con version electrical power mechanical power increased power delivered servo form higher current flow battery increase current drain battery need larger batteries order have same sort operating time get standard batteries standard servos increased drain batterys ca pacity consideration could simply plug larger battery sys tem forget about Unfortunately just what lot people doing apparently unaware deliberately ignoring other factors involved potential consequences doing loss servo power and/or disturbance rest system glitches Lets look power-loss thing first since put big servos big bat tery system because needed power Electrical power equal voltage times current Since other reasons want keep battery voltage nominally 48V same smaller nor mal systems get extra power using servo motors draw higher current As current flows through external circuit battery terminal other encounters resistance dis Continued page 154 Left Bill Wendts OlD Quick & Dirty flying test bed Sits Ofl floats designed Ken Runestrand Donna Wendt got picture just could cool off Arizona heat Right Note interesting wing attachment OlD See text details KRAFTY 60 DESIGNED AS TRAINER AND SPORT FLYER SYMMETRICAL AIRFOIL Wing Span 61 Wing Area 720 Sq Engine 50-61 KRAFTY 25 DESIGNED AS TRAINER AND SPORT FLYER Wing Span 511/2 Wing Area 460 Sq Engine 20-30 SHIPPING AND HANDLING $400 per kit Foreign orders write shipping cost California Residents add 6% sales tax Use Visa Mastercharge personal check money order no CODs Bank America Mastercharge designate AIRCRUISER 60 60 SIZE BASIC TRAINER SEMI-SYMMETRICAL AIRFOIL FOR ADVANCED MANEUVERS Wing Span 61 Wing Area 720 Sq Engine 40-60 AIRCRUISER 25 MID WING BASIC TRAINER TRULY BEGINNERS FIRST BASIC TRAINER Wing Span 48 Wing Area 430 Sq Engine 15-30 LOADSTAR 40 TRAINER & SPORT FL YER Wing Span 72 Wing Area 760 Sq Engine 25-60 EZ-1 2 METER GLIDER EASY BUILDING AND FLYING Wing Span 78 Wing Area 544 Sq Est Flying Wt 26 oz - U $3995 $2295 L $1 895 April 1984 57 HIGHEST QUALITY KITS AVAILABLE KITS CONTAIN BALSA PLYWOOD AND SOME HARDWARE ALL PARTS ACCURATELY CUT AND PACKAGED TERRIFIC VALUES! INTRODucTORY OFFER REG $4295 $39 $2595 $41 951 MODEL AIRCRAFT DESIGNS INC 2325 Plneforest Lane Harbor City California 90710 situation theres good chance Richard Keppel myself holding shaking transmitter Coming up next month will start review Schiuter Superior have flown now can say Im very im pressed exciting new machine Until next month suddenly find machine yawing left right tail rotor doesnt help check damaged main gear shaft-driven machines loose belt belt-driven machines tail rotor slipping BCNU Larry Jolly 5501 W Como Santa Ana CA 92703 RC Giant Scale/Beckman Continued page 57 must equal power supplied battery sum voltages around circuit must equal voltage battery current flow must same point circuit point someone probably saying So what dont have resistors servo circuits just wires battery servos Wrong Everything cir cuit has some resistance though its often very small shortest piece wire used radio installation has some finite amount resistance much Checking standard reference material find No 28 solid copper wire has nominal resistance 00653 ohms per foot Tht doesnt sound like much look what really means Lets say using wire carry current aileron servo mounted wing panel Giant Scale aircraft will probably take about three ft wire get servo radio fuse lage actually means six feet wire since current has go servo wire come back another wire current going see total 039 ohms just wire have two amps current flowing circuit will drop almost 08 volts just wire start 48V out battery servo will see 4V sipates power case servo motor large part effective resistance due forces turning motors output shaft exactly want power go rest circuit however power turned heat never reaches servo motor question now Will ever have relationships involved can ex- push two amps through wire pressed two very simple formuhs Elec- motor will draw maximum current tromotive force E volts equal cur- stalled power applied rent amperes times resistance R motor turning happens ohms E ower P equal power first applied motor hasnt voltage across circuit times current yet started turn also meflows through circuit P ommon chanical load case pressure sense tells us es circuit aileron great motor cannot wire battery servo back overcome Standard servos have stall through wire other side bat- currents 03 amps 08 amps tery total power dissipated circuit heavy-duty servos will run 16 18 amps will have push close two amps through wire time used solid copper wire example above because wire data table used solid wire actual practice use stranded wire fact dont ever use solid wire because vibration will break too easily Most RC system wiring No 28 No 26 stranded wire Stranded wire really just bunch small solid wires twisted together example No 28 stranded wire usually consists 7 strands No 36 wire Note wires number-size goes up wire itself gets smaller want real picky resistance solid wire actually little higher same gauge stranded wire differ ence isnt enough matter its favor anyway compare No 24 wire No 28 find resistance less half 00257 ohms per foot same six feet wire two amps flowing through will drop 03 volts could go larger wire cut resistance down cost larger size weight opinion No 24 stranded wire adequate reasonable compromise leads single heavy-duty servo Notice above example speci fied single servobut practice might have six heavy-duty servos drawing maximum current same time Under conditions wires battery have carry total current almost 12 amps wires probably pretty short now have worry about much current wire can carry just its resistance mentioned power dissipated resistance turns heat As wire heats up its resistance increases means heat wire gets hot enough melts fact fuse just piece wire sized melt certain current flow exceeded same reference chart lists resistance wire also lists currentcarrying capacity says No 20 wire can carry two amps sounds like its still long way what need lets take closer look two-amp figure sumes constant current flow case maximum current occurs very seldom short periods time aver age current will usually well below two amps opinion No 20 stranded wire reasonable compromise heavy-duty battery leads current has flow through switch well through wires another potential trouble spot have used com mon Noble-type switches application dont really recommend would much better off spend $3 $4 good-quality sealed switch lot suitable switches starting point can look Arrow Hart 81021 -AV its equivalent Any electron ics supply house will have what need So now youve got adequate batteries wires switches heavy-duty ser vos going hook together Well before go let 154 Model Aviation IIJLL~LLL LL 13i11 beacfl ve Marina Dei Rey .s RC Pylon Racing/Hager Continued page 151 talk about something else just inciden tally will help hookup problem mentioned earlier potential con sequence high current being drawn servos disturbance rest system dreaded glitches saw earlier voltage dropped across re sistance wire can reduce voltage supplied servo another hid den resistance circuit cant anything changethe internal resistance battery itself current supplied battery has flow through resis tance small amount voltage will dropped across voltage battery drops put load mind lets look what hap pens servos draw heavy current starting move current through batterys internal resistance causes output voltage battery drop momentarily Depending amount current condition battery drop could much volt Thats 20% nominal battery voltage anything else connected battery going see same drop receiver its decoder one-volt spike power supply can look like interfere legitimate sig nals Im convinced true source lot glitches Ive heard about heavy-duty servos used solution isolate heavy-duty servo power supply rest sys tem have using advocating several years now big bird have built has least two large servos long leads have never prob lems means some added wiring complication another switch turn thats small price pay re liable performance diagrams show its done heres handle hookup prob lem Note dont have change standard receiver/switch/battery wir ing light-duty servos such throttle ignition switch can used as-is make up special servo leads take servo control signal re ceiver usual draw power heavy-duty battery control signal draws little current dont have worry about wire size means can use large wire connectors switch appropriate size everything except connections receiver servo cut short aileron extender cable half splice proper ends onto heavy wire receiver end no heavy current worry about heavy current has flow through small wire its servo end keep lead short two three will work fine youre shorten leads servo itself thing leads over foot long such aileron servos mounted wings use threeconductor shielded cable shield connected ground receiver end JENCO PT-19 FW 190 D-9 650 ABM-3 Zero 8S0 AT6 North Amencan 10 50 Hellcat Thunderbolt Corsair 1350 SBO-5 Master Scale Series 14 25 RADIAL COWLS 4 diameter-31/2 deep 650 6 diameter-5 deepw/engine 1350 7~ diameter-5A deep1100 101A diameter-9W deep2500 114diameter-7 deep2200 Other sizes anailahie COWLS FOR OTHER KITS PILOT Christen Eagle 60 18 00 MIDWEST Pills Special 15 00 STAFFORD B-24 set 0141 1350 ASTRO-FLIGHT Porterlield 650 QUARTER SCALE BALSA USA J-3 Cub 1300 BALSA USA J-3 Cuh w/engine 1500 J5 ENT Stinson Voyager 1375 SIG J3 Cuh 1300 w/engine 1500 PILOT Decathlon Citahria 18 50 WHEELPANTS 7 longfor3 wheel825 10longfor4l-5 wheel1350 10long 4-5 balloon tire1600 13long br 6-7 wheel1750 Other sizes anailahie COWLS FOR PLANS MAULE LUNAR ROCKET Model Aviation January 1982 Quarter scale hy Dow Palumbo Myron Pickard2500 CITABRIA Flying Models May 1980 Quarter scale Tony Lombardo 1925 Wheelpants 11 long pr 1400 SCHWEIZER Model Airplaee News Non 1981 Dcc Mathews700 Send SASE br latest complete listing TO ORDER Please send $200 shipping charge within US VA residents add 4% sales tax Outside US send $100 br complete list eoact shipping charges PHONE ORDERS & INFORMATION Accepted 1mm 9AM-9PM EDT NOTE NEW ADDRESS AND PHONE NUMBER Formerly 01 Bay Shore NY FIBERGLASS MASTER Dept MA Rt 1 Box 460 Goodview Va 24095 703 890-6017 cable Note shield con nected servo end reduces chance noise pickup long leads Cable use available electronics supply houses Ask Alpha No 3212 three-conductor shielded cable its equiv alent may sound sort complicated first its really quite simple once get used technique dont claim cure-all possible glitch will certainly make things smoother safer big bird Bob Beckman 8248 Holly Grove Ct Manassas VA 22110 FF Duration/Meuser Continued page 63 Livno site flat plain measuring 7 12 kilometers thats about 42 72 miles mountains distance western eastern flanks Livno lies about 100km east Split Bosnia flat plaun truly fiat No hills trees bushesjust absolutely nothing 7 x 12km area surface covered green grass several inches deep About foot beneath top soil layer soft limestone probably no trees other vegetation also told plain floods winter months place vast featureless can actually get lost lose sight launch point plain used commercial agricultural purpose ex cept grazing handful sheep cows tended herders no fences can drive anywhere area although retrieving foot simplest procedure about week time wind never stronger mild breeze Most time would have called calm Several days over cast slight rain fellbut long Threatening clouds appeared hung near Continued page 158 COMPLETE THIS FORM AND AlTACH MAILING LABEL FROM RECENT IEiY2T ISSUE LET US KNOW WHERE YOU ARE GOING move please let us know advancesix weeks requIred change address Attach current MA maIlIng label check appropriate box mall Subscrip tion Dept Model Aviation 11010 Samuel Morse Dr Reston VA 22090 Check appropriate bnxenclose payment LI NEW SUBSCRIPTION 0 CHANGE OF ADDRESS Non-AMA subscription rates $1800 12 months US possessions elsewhere including Canada Mexico $2400 US Schools $900 US Libraries $1350 NAME ADDRESS CITY/STATE _____________________________________________ ZIP _______________ MODEL AVIATION 1810 SAMUEL MORSE DR RESTON VA 22090 April 1984 155 oIu Kadet MKI MKII6 50 J-3 Clipped Wtng Cub700 1/4 J-3 Cub 1300 w/engine1500 Citabria Skybolt925 Bonanza Cessna 172 LibertySport orTOP FLITE Smith Minibiplane 0P-39 Airacobra750 Ryan STA. 1200P-40 Warhawk900 P-47D Thunderholt1000 F4U-IA Corsair F8F-2 Bearcal11 00 w/engine.. 1500 pants pr1400 blisters.2200 P-Si lull length cowl .2200 P-47 lull length flaps3000