Mirage F1 (oz13201)

About this Plan

Mirage F1. Radio control scale model. Pusher prop layout, for .40 two-stroke engines.

Quote: "Mirage F1. Pavel Bosak describes his pusher version of this French jet. Designed for.40 two-stroke.

Following on from the F-15 Eagle, I wanted to build another semi-scale model with a pusher engine and decided on the French Mirage F1. This model is a little smaller than the F-15 and it is designed for use with a 6.5cc engine. The undercarriage is fixed and the wing and tailplane surfaces are larger than true scale which improved the F1ight characteristics and did not detract from the natural elegance of the plane. Although the wing loading is quite high, the model is easily controllable even at very low speeds and high angles of attack.

This is not a total beginner's model since it is very fast and capable of speeds in excess of 200 kph, but landing with a pusher prop should not be too much of a problem for the more experienced pilot. Although the Mirage is designed for show F1ying or semi scale competitions, it is quite capable of basic aerobatic manoeuvres - loops, rolls, stall turns and more.

Construction: Start by cutting out all the fuselage parts so that you have a 'kit' consisting of the fuselage sides, formers F1 to F5, rudder, elevator and engine mount. The steerable nose wheel is screwed to former F2 and captive nuts are epoxied to the top of the engine mount. The sides are strengthened with 1mm ply in the areas of the undercarriage and engine mount.

The fuselage is now easily assembled since the fuselage bottom is flat at and all formers are the same width. Cement beech undercarriage mounts between the sides and then fix the undercarriage. When this is dry, the model can stand on its wheels and this makes further construction much easier.

Wings: Construct each half separately. Glue ribs W1 to W7 onto the main spar W8 and add the false leading edge W9. Sheet the whole of the underside of the wing. Make a notch in each fuselage side to accept the main spar and glue the wings in place using rib W1 as the main glueing surface and joining the two spars together. Strengthen this joint with strips of glass fibre. Install the aileron pushrods and top sheet the wing. Add the leading edge W10 and the wing tips. Glue formers ACH2 - 5 on the fuselage and install the fin and rudder.

Sheet the fuselage between formers ACH2 - 5 but leave the fuselage bottom open. Make former F2A before adding the top front sheeting. Glue in the cockpit floor and fix the pushrods for rudder and engine control. Note that the fuel tank is fitted near the point of balance and a Robart fuel pump or similar is used between the tank and the engine.

Sheet the bottom of the fuselage from former F3 back. The fuselage sheeting forward of this point has two removable covers for access to the servos and receiver. Sand the nose cone from maple or spruce and hollow out the inside to house the battery pack. Fill and sand the entire model several times until you achieve a ready to paint surface.

Once satisfied, cut out the ailerons and remove 10mm from the wing and aileron sheeting. This should be replaced by solid 10mm balsa for strength. Attach the ailerons to the wing with nylon hinges and sand the entire wing again. To get a more authentic look I suggest you add a pilot, instrument panel and ejection seat. The canopy is plexiglass moulded over a plug. If required, this can be supplied.

Finishing the model: The whole model was covered in thin modelspan and given six coats of clear dope. The colour scheme was achieved using acetone paint and the panel lines and rivets were added with a mapping pen and Chinese ink. The model was given a final coat of clear fuel proofer before installing the engine and radio. Be careful with the balance point as shown on the plan. Do not move this point more than 10mm forward. Try out all the systems - engine, fuel pump, radio etc, and then you are ready for the maiden F1ight.

Flying: If the model has been built well and the balance point is right, there will be no problem flying my Mirage. On take off, allow the model to run for longer than you would normally do for a tractor model. If you haul off too early, the propeller will touch the ground. After about 60-70 metres, a touch of elevator will lift her off. Do not be surprised by the model's speed once it is airborne. It is very quick and lively and will perform most aerobatic manoeuvres although you need more air space than with other models powered by this size engine.

Landing needs a little care. If you have a long runway available, the answer is to land at a higher than normal speed and let the speed decay once you are on the ground. If your available runway is not long enough, it is much better to cut the engine before touch down and avoid breaking the propellor that way.

The model is very forgiving in the glide and will fly nose up at 15-20 degrees and still be perfectly controllable. I hope you have fun building and flying my Mirage. "

Mirage, R/C Model World, September 1989.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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