> Russell,
> Do any aircraft use that principle to reduce wing tip vortices?
> George ( down under)

There have been a number of research projects by NASA and others over
the years.  For example, see the X-29:

http://www.nasa.gov/centers/dryden/history/pastprojects/X29/index.html

The significant stumbling block is that forward swept wings are
inherently unstable (a minor yaw causes a pronounced roll in the
*opposite* direction).  The experiments have used computer-augmented
control to maintain stable flight behavior.  The reliability
requirements of commercial aircraft will probably preclude using
computer-augmented stability, and therefore forward swept wings.  Don'teven dream about it appearing in GA.  It is still a possibility in
military aircraft.

Russell Kent

Russell, I was under the impression that if one kept the forward
sweep to less than 5deg from Centerline, it created negligible changes to flight
characteristics, however I think it made no improvement
as far as efficentcy either.. but was a fix if the spar carry
through had to be moved back a bit.

Jarrett


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