My proposed idea was created while draining the excess water from my pool cover by using a simple gravity siphon. The basic concept is that of a turbine engine, but without the combustion phase, this is a completely air driven motor. The craft this was designed for is also another silly creation of mine, and the engine has to be in forward motion to function properly. The basic design is:

Stage one: Air is compressed into chamber 1 via a one way valve and a compressor unit found on the turbine engine.

Stage two: When chamber 1 is highly pressurized, a valve would open at the opposite end of the chamber, sending the pressurized air through a rocket nozzle creating a small amount of thrust.

Stage three: As chamber 1 empties it creates a vacuum, opening the valve and pressurizing with air again, then going back to Stage one.

I am not an engineer, nor do I claim to be one, however I hope someone here has the knowledge or experience to just tell me if this idea would work, and why it won't. So far the only problem that might come up would be the chamber wouldn't create a vacuum when emptied, but that could be fixed by adding a second, reversed fan at the rear to pull the air from the chamber.

It should work. Thats the same principle that the toilet works on you know.

That is, the siphon effect.

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...then you would just be expelling energy created from the air compressor.

could work but doesnt sound efficient.

Ditto.

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Yep, I wasn't shooting for efficiency, just a source of clean propulsion to move a blimp-esque scifi vehicle along. Thanks for the responses

It wont be clean though... how are you running the compressor?

Also, at low speeds, a large mass of slow moving air creates more thrust per unit of energy than a small mass of fast air... you may be beter off just running the compressor straight out the back.

Not 100% clean, but cleaner than a standard combustion engine. The compressor would be run from either a small amount of electricity or just by the continual depressurization of the chamber and forward movement of the craft.

If you make it comrpess by the forward movement of th craft, that would be 'perpetual motion', and wouldnt work. the pressure and thrust generated would be more than offset by the friction of the frontal area of whatever is catching the air.

If you have electricity, you migh taswell just run an electric motor'd propellor, it would be far more efficent.

Thats funny, all along I wans thinking he was trying to figure out how to drain his pool with a gravity siphon....

Still, its not entirely perpetual motion because the potential engergy fall of the water can provide motive AND propelling force, albeit not enough to keep it moving on a small scale.

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uhhh.. hes talking about propelling an air ship.... not draining his pool.

hes siphoning air, and the loss in potential energy when its released is the same as its gain when it is pressurised.

In a siphon, because the water flows downhill for at least as long as it goes uphill, it means the downhill side has enough energy to pump the uphill side.