F2D Planes

This is a 2006 Viko F2D plane. After they arrive you have to attach the supplied tail, horn and pushrod to make them complete.
The leading edge is made of styrofoam with spars running the length of the wing on the top, bottom and front. It is wrapped in stiff paper and wound with Kevlar thread to give it tortional stiffness. The remainder of the plane is made of strong trailing edges (spruce?) and balsa ribs. The centre rib is made of pieces including hardwood, spruce and balsa. The entire plane is covered with clear polyester film (Mylar) which is heat-shrunk to provide a taut skin. All up, the plane has a wingspan of 1.15m and a weight of 440grams.

The engine is a Cyclon PC7, the latest in the range at the time of writing this (Sept 2006). Cyclons are regarded as a good, reliable, economical engine for F2D competition. The PC7s seem to perform very well, although they aren't popular at the World Championships (where the slightest performance edge is worthwhile). The propellor is a Moscow #1 with (I think) carbon-fibre and fibreglass reinforcement and is about 150mm in diameter. The engine itself is mosty aluminium except for the steel crankshaft and bearings. The F2D regulations restrict the venturi intake diameter to 4 mm. The brass wheel is the fuel mixture needle-valve. F2D engines universally use Nelson glow-plugs for high performance. The mandatory muffler fits into a cutout in the plane and is retained on this plane with a small cable to the engine mount. The aluminium engine mounts are matched to the engine and generally have a couple of degrees of engine "offset" (pointing the engine towards the outside of the circle) for more consistent control-line tension. They have slots for the bolts attaching them to the plane's engine block, so that the weight of the engine can be moved forwards or backwards to finely adjust the balance of the plane (which affects stability versus how tightly it can turn).

The planes, engines and fuel system must withstand turns of around 50g. This means the usual method of the engine venturi sucking the fuel from the tank will not work (not during a turn anyway). F2D planes use what's called a bladder which is inflated like a sausage balloon with fuel. This supplies the fuel at very high pressure to the engine (enough to keep fuel flowing through the tightest of turns). The bladder tubing is latex (usually with some nice coloured UV protective skin) and is sometimes covered with a common "airship"-shaped balloon so that if it bursts (not uncommon), it won't soak the inside of your model. The photo shows the empty bladder in its compartment which stops it flopping around when the plane is turning.
At the top of the picture you can see the streamer hook. Its a loop of wire which allows the streamer to be quickly removed, so that it can be transferred to your backup plane if this one crashes.
At the left, you can see the black plastic bellcrank and aluminium pushrod (this is inside the model - you can't see the film covering).

The plane is attached to the lines using small hooks (onto loops on the ends of the two control-lines). After hooking up, a piece of fuel tubing is slid over the connection to secure it.

The detachable tail is quite thin (tapers from 3mm to 2mm at TE), but is reinforced with something in the centre section. The hinge wire is simply sticky-taped onto the tail to stop it from coming out (centrifugal force also helps to keep it in). Lots of thread binding (Kevlar?) to hold the tail mounting area together.