Free Flight: Sport and Scale

FREE FLIGHT SPORT SCALE U ru f1iirL- LMr m jail U PENDULUM CONTROL Free Flight FF Scale Models couple reasons dont see Scale models equipped pendulums stability flight modelers dont know what pendulum does model airplane know arent willing put time takes install pendulum isnt much hassle additional work too much some want Scale models have best opportunity successful flight dreaded spiral doing hope give try find out gratifying see Scale model under control pendulum easiest flying surface model control pendulum rudder yaw what gets Scale model troublespiral instability refer Scale models am talking about power models gas/diesel Electric Therefore will talking about hooking up pendulum ailerons modelers familiar pendulums Scale models think hanging pendulums swing back forth old grandfather clocks usually hooked up rudder Ive seen pendulums work model goes tight turn under power mass pendulum affected centrifugal force creating tighter turn causing crash pendulum hooked up ailerons flight pattern typically safe banking turn model banks pendulum reacts model straightens out back safe bank etc truly spectacular see model fly under control pendulum Figure 1 shows pendulum installed center section parasol-wing model use 3/s-ounce fishing weight CyAd cyanoacrylate glued 1/16 piano wire flattened vise make piano wire four inches long 1/2 inch-long brass arm soldered inch pivot end makes 14 mechanical ratio Keep mind will going short arm long arm short long etc what gives system mechanical advantage wont believe much advantage doing way bellcranks made brass sheet 010-015 thick short piece 1A2 ID inside diameter brass tubing soldered bellcrank act bushing simple way assure bushing straight take small piece pine etc drill /16 hole Put tube hole slide bellcrank until rests flush block solder wire used except pendulum will 1/32 piano wire key assembling whole system has absolutely friction-free can no part system binds including ailerons Small nylon commercial hinges used Radio Control work fine have no slop putting channel-shaped wire over pendulum can restrict movement ailerons dont need much /16-inch movement might obvious cannot have thin rib cross-section because pendulum has hang downwardthe better Figure 2 shows hook up system cabin types parasols rib thickness isnt enough install wing Note axis pendulum attached 100 wedge glued onto bulkhead add small strip fiberglass ensure will come loose wedge makes pendulum sensitive cant give scientific reason friend Jack McCracken made testbed three kinds pendulums first vertical pendulum second axis vertical arm angled back third arm angled downward 100 wedge Jack placed testbed instrument panel biplane FIG2 7 PIVOT TORQUE TUBE 7 100 1/8 BALSA WEDGE -BULKHEAD ALUMINUM TUBE SIDE VIEW OF PENDULUM ARRANGEMENT FOR CABIN OR PARASOL DESIGN 106 Model Aviation 1 BRASS SLEEVE FOR ADJUSTMENT II TOP VIEWNOT TO SCALE 1/4 THE LENGH WIRE x- ALUMINUM TUBE BRASS STRIP SOLDERED AT RT ANGLE ANGLE WIRE AS MUCH AS POSSIBLE ALUMINUM TUBE flying could see pendulums responded actual flight vertical pendulum coordinated turn did nothingit just hung other two wedge reacted favorably flight Its clever way testing idea pendulum nearly horizontal plane opposed vertical vertical pendulum affected centrifugal force tight turn will give unwanted turn crash preferred pendulum affected centrifugal force because force would have overcome gravity bank model pendulum installed youll see what mean wire arms going out ailerons actually torque tubes wire used torque tubes should heavier ailerons will bendy under flight loads arrangement Figure 3 used low-wing models biplanes have ailerons bottom wing problem setups links have precise pendulum centered ailerons tough order have some adjustment brass sleeve needs installed arm can lengthened shortened necessary Figure 3a shows solution adjustment add additional arm have line up scale position aileron horn link between arm horn has brass sleeve adjustments can made easily important work out whether arm should point up down incorrect ailerons will hooked up backward model has removable wings can hooked up pendulum linkage make wings can removed using tried-and-true tubes fuselage piano wire wings have hooks mounted root ribs rubber bands stretched between hooks keep wings place pendulum hookup amounts two telescoping brass tubes Y16- 3A2-inch OD [outside diameter] Insert smaller tube larger about /8-inch squeeze tightly pair pliers Remove tube file edges smooth insertion smooth smaller flattened tube soldered onto arm coming out fuselage flattened end mounted vertically Plug wing insert larger tube onto wire end plug smaller tube solder assembly attach tubes vertically accommodate dihedral An access panel might order wing root two brass tubes join chance misalignment access will allow see plug tubes together Just because model equipped pendulum doesnt mean can have kinds warps engine set zero thrust center gravity out limit etc model will fly perfectly aid links free ailerons work perfectly bank model back forth will rewarded efforts Sandy Peck Peck-Polymers handling new line spoked wheels rims tires made resin spokes monofilament wheels come painted look very nice Sizes range 3/4 1 1/2-inch diameter cost $30 regardless size Sandys address Box 710399 Santee CA 92072-0399 fairly new publication Stick Tissue Modelers Album Tim Bucher quick look cover might think Hannan publication soft-cover booklet features 10 model plans pull-out sheets requiring no staple removal Eight nonScale couple Scale models chapter models describing construction suggestions flight trim also information propellers rubber motors flight trimming book great value $1495 can purchased Peck-Polymers easiest way get hold E mail fkramos@attnet usually reply same day receive message 1999 107 FIG 3 -SOSOUEEZED BRASS TUBING USED FOR PLUG IN WINGS FIG 3a AILERON HORN ALTERNATIVE ONLY ONE SIDE SHOWN