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From: dick@zombie.dtc.hp.com (Dick Lucas)
Newsgroups: sci.military
Subject: Re: MHD Drives; also more on the Il-76.
Message-ID: <1990Jun6.142300.5331@cbnews.att.com>
Date: 6 Jun 90 14:23:00 GMT
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From: dick@zombie.dtc.hp.com (Dick Lucas)

If you think about it, your explanation where the pressure is higher on the
forward part of the propellor will cause the thrust to be reversed from what
normally happens.  A propellor works much the same way as an aircraft wing,
with the low pressure on the forward (upper surface in the case of a wing)
surface.  If the pressure gets too low, the water will boil (cavitate) and 
the forces generated when the small bubbles collapse can be high enough to
erode metal.