About this Plan
Triad. Simple control line profile model.
Quote: "The Triad, by Ray Malmstom.
A SPORTS-TYPE, control-line model, must possess at least three virtues - it must be easy to build, simple to fly and quick to repair. Triad has these three virtues in good measure. It is based on the full size midget racers that have been so popular in America, and it flies fast. You'll be impatient to clip the lines on to your Triad and start up the engine, so here are some important points in the construction. The plans and easi-build sketches give you the stage by stage procedure.
When tracing the fuselage shape on to sheet, you may have to join a small extra strip on to the 3 in. wide sheet. Some hobby stores stock 4 in wide 1/4 in thick sheet, and then this joining will not be necessary. You will need a vice to bend the 14 or 16 swg wire for the under-carriage. Use strong thread and plenty of cement to bind the undercarriage wire to the 1/4 in thick plywood engine mount. The engine mount should be drilled to take the engine you intend to use, before assembling the mount to the fuselage. The holes on the plan fit the American Cox .049 cu in Medallion glo-plug engine. Other engines (diesel and glo-plug) from 1 cc - 1.5 cc are suitable. They should, of course, be fitted with a silencer.
When sandpapering the wing to correct section. take care to leave the centre section as shown in the sketches. The centre part will then fit snugly into the cutout in the fuselage. The fuselage and wing can be doped, two coats clear dope, sanding lightly between coats, and painted and colour trimmed before assembly.
Assemble the wing to the fuselage before fixing the bell-crank in place on the engine mount. It is advisable to fit the control-rod and lead-out wire to the bell-crank before assembling this unit to the engine mount. Great care must be taken to see that the bolt holding the hell-crank assembly is a tight screw fit in the hole in the engine mount. The whole weight of the model plus centri-fugal effect is taken on this bolt when the model is flying, check that all the controls move freely. Paint must not be allowed to clog or stiffen the tape hinges.
Control Lines must be precise. When connecting the control-rod to the elevator horn, check that the hooks formed on the ends of the lead-out wires are level with each other when the elevator is level (at neutral) with the tailplane. Adjustment can be made to the elevator-horn before the cement holding it in position finally hardens. This is important. Also, see that the fin has rear portion turned to the right by a quarter-of-an-inch (model viewed from rear).
The wheel fairings are optional. If you will be flying from short grass they are best omitted. If your take-off will be from concrete, the wheel spats can be fitted to improve Triad's looks. Lightly cement the lower cowling blocks in place and sandpaper them into smooth nose contours, then remove them and drill out the engine bolt recesses. Do not finally cement them in place until you have bolted in the engine.
The fuel tank shown can be purchased at your model shop (cost 3s 6d, approximately). It is held in position with Evo-Stik contact adhesive. One of the two vertical pipes maintain a pressure feed to the engine, by air pressure, while the model is airborne. Connect the tank to the engine with a small length of neoprene tubing.
When your Triad is completed and before bolting on the engine, give the entire model a coat of fuel-proof dope. This prevents the fuel from softening the cement. With a 1 cc engine, fly your Triad on 25 feet approximately of strong nylon thread lines. You can use a 30 foot line with engines of greater power."
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