This is no more difficult to devise a design for than building the plane or jet itself and is well within the technological capabilities of any of the modelers on this site. I'm assuming of course the aircraft involved is large enough to carry a little extra weight, cause it will need to in order to carry the slight extra battery weight to ignite the seat. Basicly the design can be powered by an estes mosquito, ie their smallest size engine. Design the entire seat to clear the cockpit and to be inserted onto a wire upon which it slides up and down. This is the same wire and tube design used in the launching of most model rockets, and one on the back of the chair might do the trick. Some static tests with a dummy seat and model on the ground to see that it doesn't bind and is balanced when the rocket pushes it off the rail would be recommended. The rocket engine could be placed in a few different spots, but most likely, directly under the seat, ie the pilots arse, would be the best thrust/balance point. a small metal blast funnel should be created to channel the rocket flame out of the fuselage, and it can exit the bottom of the fuselage under the seat via a small metal tube which extends the funnel. The engine is simply ignited via your transmitter with a "simple switch" which you can buy and attach to your rx. When hit, this switch channels the power of two series wired 9volt batts to the engine, setting off the eject function. The main problem will be the canopy. I would reccomend a spring loaded canopy that you "fire first' with a servo, then hit your eject function to spit out the pilot. The reason for this is, that the rocket engine will not have built up enough thrust/momentum to push the pilot and chair hard enough to pop off anythiing but the weakest of canopy attachments. Unless your real good at designing something so sensitive that it can stay on in flight, yet be popped of at the slightest touch of the chair and pilot pushing up on it, its not going to work reliably. Therefore, something springloaded and servo driven for the canopy would, in my opinion, be more reliable. Anyway, Whatever you do, I suggest you do a lot of SAFE experiments first in a SAFE location, and to you young-uns lokking to just play with fire, dont try this at home.

ZOOM