Combustion Chambers

The goal of a combustion chamber is to mix the fuel air mixture, sustain ignition, and completely burn all the fuel. The trick to keeping ignition sustained is to have a rich to lean mixture in the chamber. The burning of a rich mixture is more stable and is less likely to blow itself out. Only part of the air is inserted into the front of the combustion chamber to create this rich condition. Then more air is added near the end of the chamber to lean the mixture and burn the rest of the fuel. A simple diagram below shows how this is accomplished.

Creating Thrust

Thrust is derived from Newton's Third Principal; that for every action there is an equal and opposite reaction. So the harder you blow, the more thrust produced. To blow "harder," more air can be blown, or the air can be blown faster.

To blow air faster, a nozzle is attached to the end of the engine. This acts like a venturi to speed up the air.  The nozzle essentially takes the energy of the molecules in the air and changes it to be useful. When you speed up the air it's pressure decreases (Bernoulli’s principal.) But the faster speed means greater thrust.

Now the air is shooting out the nozzle at a high speed and low pressure. Here an augmenter can be attached to increase thrust even more. An augmenter is a simple device that uses the low pressure of the jet stream to suck in cool outside air, mix it with the hot exhaust air, and direct this warm air back to create additional thrust.

At first this seems like you're getting something for nothing. But what this simple device is doing is utilizing the energy that is being lost in the form of heat. All that incredibly hot exhaust is blowing away and the energy just heats up the atmosphere instead of creating propulsion. The augmenter uses the exhaust's own properties of hot, low pressure air to warm and move extra air in a rearward direction and create extra thrust. Super efficient augmenters have an airfoil shape and can nearly double the amount of thrust produced by the engine.

The augmenter also has the benefit of changing the small amount of fast moving air into a large amount of slow moving air. Isn't slow moving air bad though? Not necessarily, now that we've added extra air to our jet stream. A large quantity of slow moving air is akin to first gear in a car. This is the best gear for accelerating. This is why propeller driven aircraft have shorter take-off distances than jet aircraft. The fast moving jet stream is more like 5th gear; it's great for cruising long distances at high speeds. (Just like commercial jets.) Adding an augmenter to the jet makes it more useful to power and accelerate a go-kart, boat, or hovercraft.

To summarize, the exhaust nozzle and augmenter work together to create an efficient jet geared to work best on a vehicle that needs good accelerating characteristics.

Ready to get started?  Please view our ONLINE CATALOG