Weathervaning

"David Megginson" wrote in message
...
That would require extremely draggy ailerons. I know that some planes
turn sloppy without rudder, but what planes don't change heading at
all? Gliders?

Gliders are the most common, most dramatic example, yes. And it's true that
even most of the "worst behaved" airplanes probably will eventually get
around to changing heading. But those that do, may still take a while to
get around to it, and even a "well behaved" airplane can demonstrate adverse
yaw. Just put in a bunch of aileron input without using the rudder and note
the heading change on the DG as the bank occurs.

If you want to find an airplane that just keeps on slipping without turning,
I'd guess that airplanes like a Pitts or some fighter jets would be good
examples. I know for a fact that the Marchetti SF260 is a good example, but
haven't had a chance to fly other aircraft with similar characteristics.
Generally speaking, less stable aircraft are more likely to not bother to
yaw in the direction of the slip, by definition.

Probably for the vast majority of airplanes, saying that they simply won't
ever change heading is an overstatement, I admit. But many will turn
opposite the bank, and many will take a VERY long time to make any
significant heading change.

Pete