"tscottme" wrote:

Mike Beede wrote in message
...

The B-2 appears to be climbing. If so, why does it have its rudders
in air brake mode (whatever the correct terminology is, please fill it
in)? When you're climbing, you'd usually prefer to *reduce* drag,
not increase it.

Mike Beede

I was somewhat surprised to learn that the slightly deployed surfaces
you see in the photo are usually slightly deployed during much of the
flight. I doubt this applies during segments when stealth is most in
demand, but as I recall it being explained, the slight deployment of
those surfaces have only a small aerodynamic penalty, if any, but at
this position they are immediately useful for aircraft control. That's
to say, from their completely stowed position until the position at
which they affect aircraft control there would be a significant lag.
Traveling with the drag rudders in the position in the photo gives a
more prompt reaction to control input. I seem to remember the figure
being that the drag rudders are deployed approximately 5 degrees from
their stowed position most of the time.

This explanation seems to be supported by the practice of some
sailplanes. I was surprised to learn that some high performance
sailplanes (gliders) actually are able to raise their flaps *slightly
above* the stowed position and achieve better lift or maybe it's speed
in that configuration.

Sort of goes along with how hydraulics work...the hydraulic
controls of sensitive items like propellers have a built in
'jitter' to the system pressure. It's explained by saying that
half the time the fluid is moving in the direction that it's
needed to move, this makes for a more immediate response when
demanded.

Don't kill -me-, kill my many instructors...
--

-Gord.