The torus in the rocket engine
The torus in the steam engine
Torus in the combustion chamber.
Using the torus combustion chamber spike type nozzle may improve the SABRE engine efficiency and performance. The weight factor will have to be minimised.
Other uses for the torus include a torus ceramic heat shield which converts some of the reentry plasma into useable ramjet thrust, and the use of the torus in the ion engine designs.
As much as these ideas sound fanciful, they are taken seriously by advanced engineering companies. Some have already patented the Torus design in anticipation of parasitically hijacking future development tracks!
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