How come the wings bank when I use the rudder

Dudley Henriques wrote in
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Bertie the Bunyip wrote:
Dudley Henriques wrote in
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Bertie the Bunyip wrote:
Dudley Henriques wrote in
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Bertie the Bunyip wrote:
Dudley Henriques wrote in
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Bertie the Bunyip wrote:
Dudley Henriques wrote in
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Bertie the Bunyip wrote:
Dudley Henriques wrote in
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Bertie the Bunyip wrote:
Dudley Henriques wrote in
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Bertie the Bunyip wrote:

OK, I think I have it. There're (roughly) similar
problems
with
the
transonic stuff I fly but for some different reasons.
Surely
there
are some buffet isssues with the ailerons at large
displacements
as
well?




Bertie
I've not noticed aileron buffet in the 38 even at max
deflection. The ailerons are extremely effective on the
airplane. About buffet; you actually work high performance
jets
like the 38
by
using the buffet boundary. You can pull the pole and feel
the
buffet
onset in pitch. It's a highly effective warning when
maneuvering
hard.

you're talking mach buffet now, right? not normal flow
seperation..

I would have thought you might get buffet problems with
large
deflections in and around transonic flight. We can,
certainly,
but our airplanes aren't desingned for supersonic flight,
of
course..

bertie
The buffet limit is actually the subsonic buffet limit and
defines
the
lift limit line for the 38. In other words, below corner
speed,
you are aerodynamically limited in maneuvering room by the
lift
limit
line
which basically means you can pull to the buffet.
In effect, the tactical buffet line defines the left side of
the
T38's
flight envelope.
Yeh, OK I understand buffet in relation to loading but the
control
deflections have no effect on the onset of buffet? Is that
not
why
you
have a limit when close to mach 1?

Bertie

The roll restriction is totally unrelated to tac buffet. For
all
practical purposes you can forget aileron buffet as a problem
in
the
T38. The issue with the roll limit is divergence through
inertia
roll coupling. In other words, at the q found at .9 Mach and
above,
max aileron throw will generate a roll rate high enough that
the
roll axis changes from pure roll and couples either in pitch
or
with
yaw or even both under specific angles of attack as the roll
is
initiated; and
this
NEW roll axis is so unstable due to the IYMP that departure is
a
real possibility.

OK, which is what you posted originally before I went off on a
tangent! I suppose I was thinking that the divergence was
started
off
by a mach buffet triggered by the ailerons, but I'm with you
now.
I
think..


Bertie
We'll have you checked out in the 38 in no time :-))

Heh he, 'Who'd pay for the gas?


Bertie
That's the secret. The only guy I know who can afford to fly these
things without actually getting paid to fly them is Ross Perot
Jr.,
and
even he's in a world of trouble with his T38. He's caught between
the
government and his lawyers. I can't think of a worse place to be
than
that :-))


Yeah. I have an offer to fly in an old jet fighter. I only have to
put
gas in it and that comes to nearly a grand for an hour!


Still, I think I'll do it. Al I have to do is find a window when he
actually has it running!


Bertie
Sounds like fun. What is it?


Vampire.


I think you'll be surprised at how easy it is to fly.


According to the owner, it's a piece of cake.

About like a high perforamnce single, but with very short endurance.

Contrary to
popular belief, I've always felt that the faster they fly the easier
they are to fly. You can do practically everything you need to do in
the
T38 for example with your feet flat on the floor. Practically no
adverse
yaw at all. It's a dream to fly.
Good luck with your flight.
D

Thnaks! Won't be anytime soon. I think they broke it again.


Bertie

Vampire? The side by side version I presume?
Remember that great scene in "Breaking The Sound Barrier" when the
"hero" takes his wife on a trip from England to Egypt in a two seat
Vamp? Beautiful black and white photography in that picture.


I do actually. I love the way they make it look like they did it
first...




Hope you get to fly it. Nearest thing I can relate to that I've flown
would be the Canadair Tutor. I flew the Snowbirds #10 as a guest of
the
team at one time. Great little airplane and very easy to fly.
I'm sure you won't have the slightest problem with the Vampire if they
ever get it running.
D


Oh it's often running, then its broken, then it's running, then it's
broken! The lost the canopy on it once and it cost more to replace than
it hadcost to buy the airplane!


I have a pic of the snowbirds in Sept Isle Quebec I took in 1979, I
think. They had just flown through Mt St Helen's plume and damaged their
airplanes! I didn;t get up close to them, but I was up in the tower and
the controllers told me their windscreens had been badly frosted by the
incident. I'll have a rumage around for it.


Bertie