"Bruce Simpson" wrote in message
...

There are significant problems to using PDEs as a propulsive source.
The magnitude of the shockwaves produced is extremely high as are
the
levels of vibration.

A craft using such a power-plant will need some very special
attention
paid to the acoustic and physical isolation of the engine.

Sounds like a micro-Orion. Now, there's an engine with _real_
acoustic and vibration problems! ;-)