"Darrell" wrote in message
news:FAjBc.20218$ey.9317@fed1read06...
The B-47 had neutral aileron control at about 425 knots (as I seem to
remember). Above that speed it rolled in the opposite direction than the
control input. It was because of the flexible wing. Approaching 425 (if
that's the right speed), the roll produced by aileron input reduced to no
roll at all at 425, then it would roll opposite the control input above
425.
It was, as you noted, because, above 425, the aileron served merely as a
tab
which ended up twisting the overall wing in the opposite control
direction.


I believe that the B-47 aileron control characteristics you mention are
close to the facts, and I recall that the "red-line" speed vs roll control,
was handled in a rather unusual manner.

During the late 1950's, some B-47 units were tasked to fly low level
"LABS" missions. At some speed near the "red-line" (it could have been 425,
it was long ago!), the wing twist would cause one wing or the other to
become increasingly "heavy", and increased roll trim would have to be
cranked in to maintain level flight. Each aircraft was slightly different
than others, so an aileron rerigging program was begun, to rerig all ships
ailerons to near perfection and then test fly each one to determine how much
aileron trim was required to maintain level flight at some speed (I thought
it was higher than 425, but hey, that was in maybe 1958 or so). Then, if
more than 20 (?) units of trim were required, the aileron of the "heavy"
wing was carefully rerigged a couple of degrees below neutral, and the test
flight was repeated.

This process went on until all the 303rd Bomb Wing ships except one met
the new criteria. The one that did not respond got a meticulous (sp?)
alignment check, and one wing was found to have a permanent twist, exceeding
the -3 structural manual's service limits. Deep down in the procurement
documents it was found that that particular ship's right wing was out of lim
its when accepted by the AFPRO from Boeing.

Old Chief Lynn