Expansion turbines thrust

When combining compressors, expanders, and turbines, the speeds, thermal expansions, and thrust loads on shaft systems exist at different magnitudes and directions. These must be managed and accommodated with skill and experience. 

Ramjets, or propelling nozzles, operate with neither compressor nor turbine. The air taken in by the diffuser is compressed due to its rate alone and the expansion of burned gases in the nozzle ensures the propulsion by the reaction. The thrust is equal to zero at rest, and the necessary speed must therefore be reached using an auxiliary engine or a rocket. 

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