How come the wings bank when I use the rudder

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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.

--
Dudley Henriques

Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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 :-))

--
Dudley Henriques

Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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 :-))


--
Dudley Henriques

Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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

--
Dudley Henriques

Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
news
Bertie the Bunyip wrote:
Dudley Henriques wrote in news:1dCdnWn-
:

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.
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

--
Dudley Henriques

On Oct 21, 3:56 am, Bertie the Bunyip wrote:
wrote in news:1192935582.999886.201640
@t8g2000prg.googlegroups.com:



In addition to what others have said, another interesting question to
ponder is why the airplane yaws when you bank.

The yaw is induced by the ailerons, so the only time you need to apply
rudder is when you are changing your bank angle with the ailerons. On
the side where the aileron is down, the wing has more lift, and more
drag. On the other side, the lift is spoiled and there is less drag.
The draggy wing yaws backwards, requiring opposite rudder.

that's adverse yaw. I beleive he meant why does the airplane yaw in the
same direction (eventually) as the direction of roll?

Bertie



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Bertie,

I assumed that adverse yaw was what he was asking about since it is
the most pronounced effect.

To answer the question the other way:

The reason for rudder use in a sustained bank is due to the fact that
the airspeed of the outside wing is slightly higher than the airspeed
of the inside wing due to the difference in arc-distance that each
wing is traveling in a turn. The outside wing has a little more drag
due to the higher airspeed and a little bit of rudder is required to
compensate.

Dean