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This question already has an answer here:

Pretty self explained in the title.

Yes, I realize there is no widespread demand for them; this is not what I'm looking for in an answer.

I'm looking for an answer that covers more why they can't be built (or aren't practical to). I know that jet engines may generally be better, but I've recently been doing reading on aircraft like the Thunderscreech and it's made me curious why exactly it won't work.

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marked as duplicate by Sanchises, fooot, abelenky, Dan Hulme, Farhan Mar 16 '18 at 15:43

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ The blade has 0 velocity near the center and maximum velocity at the end, so somewhere in the middle you will get hit by the bad aerodynamics of transonic. Maybe you can develop a ring shaped propeller that operates mostly in the supersonic region? $\endgroup$ – user3528438 Mar 16 '18 at 14:53
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The NASA has done research on the supersonic propeller at the end of WWII, which can be found here and here.

The main reasons that we don't see any supersonic propellers are the following:

  1. The supersonic regions at the blades create tremendous forces which will tear the propeller apart. Thus the design needs to be such that these forces can be mitigated. This is also the case for jet engines, which is why the ducts are designed such that the airflow into the engine is slowed down to subsonic speeds.
  2. The developments in jet engines were going at such a fast rate that the propeller was soon surpassed and was written off. However, since turboprops are much more efficient than jet engines they might pop up on the research radar in the near future.
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