Ken Greaves checking a Wren turbo-prop unit before running it. These small units produce equivalent to 8 HP, and the tubine spins at 160 000 rpm. The reduction gearbox drives the prop shaft at 6-7000 rpm. These units, working on same principles as full-sized ones, are also used somewhat modified in turbine driven model helicopters produced here in WA by RCrotortech.

Engine in Neil's Cougar

Model rc jets have lacked the realism of having a true jet engine until recent years. Previously jets were powered by noisy, whining ducted fans or inefficient, loud pulse jets, but now they can be powered by a fully functional jet turbine.

A model jet engine can vary somewhat in design, but all work on the same principle: at the front of the engine is a spinning compressor - much the same one as found in a car's turbo charger. This blows the air into the chamber, where the the air slows down creating pressure.
The fuel, nearly always kerosene, is fed into the combustion chamber as a fine spray and mixes with the air. This fuel/air mixture is then ignited by an ordinaryl glow plug.
As the mixture explodes in the chamber, the temperature rises quickly and gases expand. This hot gas is then forced out of the rear of the combustion chamber at great speed, generating thrust.

At the rear of the model jet engine is a turbine wheel connected to the front compressor by a shaft running inside a tunnel through the center of the combustion chamber. As the hot air is forced out the back of the engine, it passes through the turbine wheel and spins it at high speed, spinning the front compressor, which sucks in more air, keeping the whole process going.
In theory it is simple, but there are lots of things that have to be right to make the engine reliable and efficient. And if you get too much heat, the combustion chamber ends up looking like this:

Mark Keech's T-38 Talon


Not so good . . .


Very large scale . . .

L-39 Albatross