On Sat, 04 Oct 2003 16:55:16 +0000, Ray Toews wrote:

I have a coffee table book which describes "some" technical detail of
the Concorde and it uses fuel transfer to trim the aircraft in flight.


The centre of pressure moves aft quite a bit in supersonic flight. If the
CG was kept in the same place it was in subsonic flight the elevons would
have to be deflected up at a significant angle to trim the aircraft, and
the drag from the deflected elevons would be very large. So, in
supersonic flight they pump fuel aft to move the CG aft and reduce the
trim drag from the elevons. But I wouldn't say they use it to trim the
aircraft in the aviation sense of the word, because you can be sure that a
movement of the trim switch makes something happen in the flight control
system rather than pump fuel to reduce the stick force.

Quite a few modern airliners have fuel tanks in the horizontal stablizer,
and they pump fuel aft in cruise to reduce the trim drag.

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
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