Re: What could replace the P-3?

Date:         17 May 98 00:43:09 
From:         "P. Wezeman" <pwezeman@blue.weeg.uiowa.edu>
Organization: The University of Iowa
References:   1 2
Followups:    1 2
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	Of existing production aircraft, I would think that the logical
choice would be the Lockheed C-130 Hercules. It is close to the size of
the P-3 and is already used for some long range weather observation
missions also performed by P-3's. An ASW version of the C-130 could
save some weight by not having such a heavily reinforced cargo deck
and possible by not having a rear loading ramp. Depending on how much
interior volume the Navy wants, it might also have a shorter fuselage,
perhaps the same length as on the earliest models.
	Given the conflicting requirements for an ASW aircraft to fly
economically at both high and low altitudes, a four engine turboprop
seems to be the best arrangement. At low altitude it can shut down and
feather the outboard engines and fly on the inboard engines at near
full RPM, where the engines operate most efficiently. At the speed used
during search, propellers are much more efficient than turbofans. The
Russians are testing an advanced counter-rotating propeller on a new
airlifter with a cruise speed approaching 500 knots, and the Europeans
are still talking about building a somewhat similar aircraft. Both of
these are probably somewhat too big for an ASW plane, but I would expect
that this type of engine would be used in preference to turbofans on a
future purpose-built patrol aircraft.
	I believe that the British Nimrod ASW plane shuts down two of
its four Rolls-Royce Spey engines while searching. Would it be possible
or practical to do this with high-bypass turbofans, which would tend
to windmill? I have seen the fans turning on an aircraft parked facing
into a moderate wind.

                        Peter Wezeman, anti-social Darwinist

                             "Carpe Cyprinidae"