Heinkel HeS 40

It was based on the mechanical layout of the HeS 30, but replaced the conventional flame cans with oversized ones including large poppet valves that sealed off the chambers during firing.

The new chambers were considerably larger than the originals, forcing a reduction in the number from ten to six burners.

Compressed air, similar to an automobile equipped with a turbocharger, but at a higher pressure ratio, was channeled into the cylinders in turn, closed off with the poppet valves, and then burned.

By the time the combustion was complete the pressure in the flame cans would be much higher, although the actual expansion ratio is not specified.

The hot gas was then released, and flowed through a turbine to extract power, instead of forcing a piston to move (although most of the output in the expected turbojet engine format - as opposed to a turboshaft - would be extracted as thrust, and the turbine only acted to power the compressor to continue the cycle).