Radio Control: Sport and Aerobatics

SERVO TESTER strikes again Ten years ago offered send schematic nice servo tester anyone sent mc SASE got sev eral hundred responses made same fer twice during past few months didnt expect receive couple hundred requests However daily mail has cluding 10 15 letters SASE asking schematic Thats great good piece equipment inexpensive easy build couple early requesters have asked calibrate dial Most servos use 15 millisecond centering pulse tester-builders can use good new lightly used servo cal ibrate dial pointer 15 milliseconds Most radio systems will vary pulse 05 millisec onds full throw normally 450 servo rotation either direction way calibrate tester First hook servo channel radio system turn system channel neu tral position stick trim center turn system off receiver first Note position servo arm Unplug same servo radio system hook tester plug battery note direction servo arm moves moving knob tester rotate servo arm until returns same position held before turned tester Assuming have pointer knob will pointing setting 15-millisecond pulses After marking setting rotate knob until servo arm moves 450 mark pointer same thing other direction two new settings represent 10and 20-millisecond pulses Which important because care servo operates smoothly quietly mark through neutral other mark will note servo will work outside 10- 20-millisecond range dont turn knob too far outside because some servos have built-in mechanical stops can damage gears driving servo beyond intended range motion Thats happen have device measures pulse width like oscilloscope can calibration somewhat accurately However intended purpose tester way Ive described works just well Good luck seems though everyone has discovered Turnaround Thats because all-Turnaround con tests held parts country last year Im sure havent heard about know about ones held Tennessee Mississippi California New Jersey name 0 LC 0 dc Figure 1 two wings have equal chords equal areas What different characteristics have installed model Van Putte expounds design psects month Figure 2 Two different rudder shapeshow will affect models thy installed 40 Model Aviation Radio Conoi Sport Aerobatics Ron Van Putte III Sleepy Oaks Rd Ft Walton leach FL 32548 Big Ag-Cat under construction Bob Murdy Carey OH 90-in wingspan projected weight 20 lb will need bit power G38 can put out should great aerobatic model few went contest sponsored Team RACE RC Club Jackson MS October enjoyable too difficult because chose lower classes Advanced didnt have learn too much interesting thing noticed airplanes kind would see AMA Pattern contest Some competitors went up bit propeller pitch get better vertical performance some didnt However Expert FAI competitors use some tricks competitive fun generally agreed nice change pace expect say converted Turnaround dont hold breath Im looking forward AMA Expert class 1988 way Knife Edge-to-Knife Edge anyway note Jackson all-Turnaround con test cant resist telling am noted support suggestions change AMA competi tion present format all-Turnaround However did compete Jackson allTurnaround contest can think has pushed Turnaround country other individual Ron Chidgey Pensacola FL hope good reason missing Deep Souths first all-Turnaround contest Sorry Ron promised Jackson guys Id pull leg missed Over years Ive published design tips var ious subjects canards tail-first airplanes dihedral sweepback subjects came nat urally because am engineer de grees aeronautical astronautical engineer ing ideas aircraft design came result teaching graduate-level engineer ing courses Air Force Institute Technol ogy during mid- late Sixties assigned classes stability con trol project designing canard airplane demonstrate theories worked fine properly applied airplane designed scaled down six-foot wingspan built flew RC model decided call Ascender say slowly after World War 11-vintage Curtiss canard fighter same name flew Ascender Don Lowes help 1966 through 1968 Ascender flew way canards almost impossible spin dont normal stalls like conventional airplane kind mush nose-down continue flying again However try accelerated stalls result ing gyrations resemble falling leaf Canard aircraft have tried people over years varying degrees success Wright Flier canard popular success years country Few people recognize canard Cap tains Milt Sanders Charlie Bair entered ca nard Pattern airplane See March 1977 issue magazine construction article Zonker available Full-Size Plan No 177 RMcM 1976 Nats Dayton OH ever idea never much popular success un til canard lovers delighted flight Voyager Voyager canard ramblings about canards resulted some letters received recently questions about design ideas including canards writ ers wanted know what effects would see going design another instance suppose compared effects changing wing shown top Figure 1 bottom What differences would expect find between aircraft Continued page 137 March 1988 41 Last An Automatic Full-Feathering Adjustable Pitch Propeller An exclusive patented mechanism lets adjust pitch 84Oo optimum perfor mance blades automa tically feather motor stops reduce drag give much Recommended 72-80 motor gliders similar models wing loads up 14 ozI sq ft 05 direct drive systems e shaft Stock No MAO8XXE $2495 Suggested Retail Available Through Leading Distributors WINDSOR PROPELLER CO 384 Tesconi Ct Santa Rosa CA 95401 PRACTICAL SIZED GIANT SCALE MODELS NICK ZIROLI Jets too OC-3lA 1140 Span$4200 F4U CORSAIW2 193 Span$3000 ASMS ZERO2A 191 Span$3000 CuRTISP402A 194 Span$3000 AT-e TEXAN24 1101 Span$3000 F5F BEARCAT2A 186 Span$3000 FOKKERDR-127 183 Tripe$2700 Canopies Available Plans Sent Post-Paid within USA Send 5O Full Catalog Balsa Order Nick Ziroli 29 Edgar Dr Smithtown NY 11787 USA BUT come -in-bore pinion gear have mounting hole locations allow used ferrite OSs means can replace troublesome smallshafted reducers real brute keep us ing motor have cost $35 list may seem high really notjust soon damage parts economy drives have get replacements Astro drive heavier additional weight quickly forgot ten can actually continue flying after making landing after landing Finally youre tired good ol ferrite 05 can use drive its intended purpose 02/035 cobalt strongly recommend product consideration Coming future columns Im personally very big so-called 15 -size motors may want motors other Also test runs Astro 4fl46 drive some ferrite OSs varied props Please forward comments questions SASE please address listed beginning column HAPPY SILENT POWERED FLIGHT RC AerobaticsNan Putte Continued page 41 featured wings Both wings have same span chord wing area same equal-weight airplanes wing loadings would same bottom wing has substantial sweepback would exhibit dihedral effect result sweepback less dihedral would required aerodynamic center top wing about one-fourth wing chord back leading edge aerodynamic center bot tom wing almost trailing edge root chord means order get same longitudinal pitch lateral yaw characteris tics two airplanes swept-wing de sign would probably need longer tail moment and/or larger horizontal vertical tail surfaces addition center-of-gravity sweptwing design would further aft differences would expect find example demonstrates relatively simple change design can cause significant changes other parts airplane Lets try Figure 2 shows two differ ent kinds rudders same airplane Which likely create yaw roll youre trying Stall Turn air plane fly Knife Edge want pure yaw input rudder Rolling messes up maneuver Which rudder did pick Pattern airplanes likely have rudders like top because effective point applica tion force rudder deflected near bottom rudder means little no rolling moment will generated about axis fuselage other hand rudder bottom sketch will have great deal rolling moment generated rudder deflected wont see rudders like good designs Ill print kind design information now again theres interest Please let know responding advertisers mention read about ModelAviation used substrate build other types finish dacron polyester heat-shrink materi al similar Ceconite Stitts Poly-Fiber full-size aircraft Its advantages long life toughness resistance puncture tearing accepts paint dope quite light requires oniy minimum finish also contributes lightness has no adhesive fabric models framework given two three coats dope sanding lighdy between coats remove balsa fuzz Use enough dope thinner promote easy brushing since thinner evap orates does nothing towards building coating Any brush will serve preference sable long stralght hairs work dope balsa especially first coat ap ply dope surface will come con tact fabric including rib edges Koverall cut its grain running direction long dimension area covered Grain direction hard detect package tells find grain direc tion runs diagonally across wing example shrinkage will likely cause warp structure wing panel cut piece Koverall about two inches wider three four inches longer wing prefer cover wing halves starting center stretching fabric wards tip Lay Koverall bottom wing Brush strip dope about t/a thinned about 10% across wing Continued page 140 Specifications Wingspan 44 Wuight9A bs Power RK-740 Kit Includes Machine Cut Sanded Balsa Ply Foam Parts Full Size Rolled Plans Instruction Guide Necessary Hardware 2240711 9 Houston TX 77227 shipping 713 621-1462 March 1988 137 RC Scale/Wischers Continued page 43 E Tactical High Alt itude __The end Zij NA SAWSfamous line hobby saws Replacement Blades available dealer PAl Model Supply Razor #200 $288 Universal #500 P0 Box 3967 Torrance CA 90610 HOBBYPOXY TRUE TWO-PART EPOXY PAINTS 16 COLORS R ER EPOXY GLUES FOUR FORMULAS 5-MIN ID 45-MIN FAST FILL GRAIN FILLER QUICK-PREP POLYESTER RESIN FREE COLOR CARD AND BROCHURE Homeypoxy DIVISION PeltS Paint Company lac 36 Pine Street Rockaway NJ 07866