How come the wings bank when I use the rudder

[Paul kgyy]

On a 3 hour cross country today I was amusing myself by flying with
rudder pedals only (all right, OK, a little yoke usage to maintain
altitude). But then I got to wondering why applying rudder pressure
causes the plane to bank. All I could think of was that rudder usage
produces asymmetric lift because one wing is somewhat blanked by the
sideways motion induced by the rudder? Also, the rudder surface is
above the plane's center of lift but I don't know how much of a factor
that is.

[Capt. Geoffrey Thorpe]

"Paul kgyy" > wrote in message
oups.com...
> On a 3 hour cross country today I was amusing myself by flying with
> rudder pedals only (all right, OK, a little yoke usage to maintain
> altitude). But then I got to wondering why applying rudder pressure
> causes the plane to bank. All I could think of was that rudder usage
> produces asymmetric lift because one wing is somewhat blanked by the
> sideways motion induced by the rudder? Also, the rudder surface is
> above the plane's center of lift but I don't know how much of a factor
> that is.
>

As you yaw, the "outside" wing is flying faster than the "inside" wing and
generates more lift which gives you bank.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

[Dudley Henriques[_2_]]

Paul kgyy wrote:
> On a 3 hour cross country today I was amusing myself by flying with
> rudder pedals only (all right, OK, a little yoke usage to maintain
> altitude). But then I got to wondering why applying rudder pressure
> causes the plane to bank. All I could think of was that rudder usage
> produces asymmetric lift because one wing is somewhat blanked by the
> sideways motion induced by the rudder? Also, the rudder surface is
> above the plane's center of lift but I don't know how much of a factor
> that is.
>
It's called a yaw/roll couple. As you create yaw you acellerate the
outside wing which then has more lift. It raises coupling with roll and
you have turn.


--
Dudley Henriques

[Andrew Sarangan]

On Oct 20, 8:42 pm, Paul kgyy > wrote:
> On a 3 hour cross country today I was amusing myself by flying with
> rudder pedals only (all right, OK, a little yoke usage to maintain
> altitude). But then I got to wondering why applying rudder pressure
> causes the plane to bank. All I could think of was that rudder usage
> produces asymmetric lift because one wing is somewhat blanked by the
> sideways motion induced by the rudder? Also, the rudder surface is
> above the plane's center of lift but I don't know how much of a factor
> that is.

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

[Capt. Geoffrey Thorpe]

"Andrew Sarangan" > wrote in message
oups.com...
<...>
> In addition to what others have said, another interesting question to
> ponder is why the airplane yaws when you bank.
>


'cause if it didn't, your feet would have nothing to do ;-)

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

[[email protected]]

> 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.

This is why when you initiate a bank, you need to apply rudder in the
direction of the bank while the ailerons are in use, but not once you
stabilize the bank and neutralize the ailerons. When you roll back
wings level, you need to apply rudder the other direction to once
again compensate for the ailerons.

Dean

[vincent norris]

Paul kgyy wrote:
> On a 3 hour cross country today I was amusing myself by flying with
> rudder pedals only (all right, OK, a little yoke usage to maintain
> altitude). But then I got to wondering why applying rudder pressure
> causes the plane to bank.

The rudder causes the airplane to yaw; one wing goes faster, generating
more lift; the other wing goes slower, generating less lift.

vince norris

[Montblack]

("Capt. Geoffrey Thorpe" wrote)
> 'cause if it didn't, your feet would have nothing to do ;-)


http://www.ercoupe.org/images/37.jpg
That would be awful...! :-)


Montblack

[Bob Clough]

What gives, guys? Good question followed by three answers that
actually agree? What's up with that? Where's the usenet controversy?
:)

Bob
> The rudder causes the airplane to yaw; one wing goes faster,
> generating more lift; the other wing goes slower, generating less
> lift.

> vince norris

--
I'm trying a new usenet client for Mac, Nemo OS X.
You can download it at http://www.malcom-mac.com/nemo

[BT]

Isn't interesting that entry level RC Aircraft only have rudder and elevator
controls.. and then turn just fine.
Funny that a full sized airplane would react the same way.

In a stall, you pick up the low wing with rudder, not aileron, that only
adds adverse yaw, more drag on the low wing, and fights the rudder.
BT

"Paul kgyy" > wrote in message
oups.com...
> On a 3 hour cross country today I was amusing myself by flying with
> rudder pedals only (all right, OK, a little yoke usage to maintain
> altitude). But then I got to wondering why applying rudder pressure
> causes the plane to bank. All I could think of was that rudder usage
> produces asymmetric lift because one wing is somewhat blanked by the
> sideways motion induced by the rudder? Also, the rudder surface is
> above the plane's center of lift but I don't know how much of a factor
> that is.
>

[brtlmj]

> Isn't interesting that entry level RC Aircraft only have rudder and elevator
> controls.. and then turn just fine.
> Funny that a full sized airplane would react the same way.

Size does not matter here. It's the wing dihedral that does.

Bartek

[[email protected]]

I'm puzzled as to how you could be doing a solo X country and not know
this. Did you first lesson not include "effect of controls"? what
about your theory?

Cheers


> On a 3 hour cross country today I was amusing myself by flying with
> rudder pedals only (all right, OK, a little yoke usage to maintain
> altitude). But then I got to wondering why applying rudder pressure
> causes the plane to bank. All I could think of was that rudder usage
> produces asymmetric lift because one wing is somewhat blanked by the
> sideways motion induced by the rudder? Also, the rudder surface is
> above the plane's center of lift but I don't know how much of a factor
> that is.

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Paul kgyy wrote:
>> On a 3 hour cross country today I was amusing myself by flying with
>> rudder pedals only (all right, OK, a little yoke usage to maintain
>> altitude). But then I got to wondering why applying rudder pressure
>> causes the plane to bank. All I could think of was that rudder usage
>> produces asymmetric lift because one wing is somewhat blanked by the
>> sideways motion induced by the rudder? Also, the rudder surface is
>> above the plane's center of lift but I don't know how much of a
factor
>> that is.
>>
> It's called a yaw/roll couple. As you create yaw you acellerate the
> outside wing which then has more lift. It raises coupling with roll
and
> you have turn.
>

Gotta disagree there Dudley. While it is true, and that's what happening
to some degree initially, the majority of the yaw roll couple in
lightplanes comes from the dihedral. the wing opposite the direction of
yaw has a higher angle of attack and generates more lift then the
opposite, which now has a lower alpha. Airplanes with no dihedral will
still roll slightly in the direction of yaw but it's nearly zilch.
can prove the first statement for yourself by introducing the yaw so
slowly as to make the diffrence in speeds insignificant. The airplane
will still roll in the direction of the yaw.
The V1 cruise missile had no dihedral and no ailerons and was easily
upset for this reason. Once it was off a wings level flight path it's
gyros had no chance of getting it back into straight and level.
Swept wing airplanes can have a huge yaw roll couple because as you yaw,
the forward moving wing's aspect ratio becomes massive just as the aft
moving's wing shrinks.(transonic ones have a reverse effect couple at
altitude, but that's another story)


Bertie

[Bertie the Bunyip[_19_]]

"Montblack" > wrote in
:

> ("Capt. Geoffrey Thorpe" wrote)
>> 'cause if it didn't, your feet would have nothing to do ;-)
>
>
> http://www.ercoupe.org/images/37.jpg
> That would be awful...! :-)
>
>

It is. I flew one of the old pedal-less ones for a couple of days giving a
guy who had rebuilt one and hadn't flown for years a re-intro to flying.
God awful!
there is a brake pedal, though. A stalk type pedal I think it came out of a
'38 DeSoto.
The Pilot's handbook said that to deal with a too high situation on
approach you should pull th estickk full aft and let the rate of descent
increase that way until you were back in the slot..

Yech.

Always liked the look of them though. Could have been worse, it could have
been the Gwinn Air car hat filled that Niche!

Bertie

[Bertie the Bunyip[_19_]]

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
>

[Bertie the Bunyip[_19_]]

Bob Clough > wrote in news:nemoSat102007091418
@newsgroups.comcast.net:

> What gives, guys? Good question followed by three answers that
> actually agree? What's up with that? Where's the usenet controversy?
> :)

Hey, I gotta slep every now and again, ya know.


Bertie

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:
> Dudley Henriques > wrote in
> :
>
>> Paul kgyy wrote:
>>> On a 3 hour cross country today I was amusing myself by flying with
>>> rudder pedals only (all right, OK, a little yoke usage to maintain
>>> altitude). But then I got to wondering why applying rudder pressure
>>> causes the plane to bank. All I could think of was that rudder usage
>>> produces asymmetric lift because one wing is somewhat blanked by the
>>> sideways motion induced by the rudder? Also, the rudder surface is
>>> above the plane's center of lift but I don't know how much of a
> factor
>>> that is.
>>>
>> It's called a yaw/roll couple. As you create yaw you acellerate the
>> outside wing which then has more lift. It raises coupling with roll
> and
>> you have turn.
>>
>
> Gotta disagree there Dudley. While it is true, and that's what happening
> to some degree initially, the majority of the yaw roll couple in
> lightplanes comes from the dihedral. the wing opposite the direction of
> yaw has a higher angle of attack and generates more lift then the
> opposite, which now has a lower alpha. Airplanes with no dihedral will
> still roll slightly in the direction of yaw but it's nearly zilch.
> can prove the first statement for yourself by introducing the yaw so
> slowly as to make the diffrence in speeds insignificant. The airplane
> will still roll in the direction of the yaw.
> The V1 cruise missile had no dihedral and no ailerons and was easily
> upset for this reason. Once it was off a wings level flight path it's
> gyros had no chance of getting it back into straight and level.
> Swept wing airplanes can have a huge yaw roll couple because as you yaw,
> the forward moving wing's aspect ratio becomes massive just as the aft
> moving's wing shrinks.(transonic ones have a reverse effect couple at
> altitude, but that's another story)
>
>
> Bertie
>
Not so much disagreement really. What you are saying is correct. All
these things happen. Technically however, the exact moment the yaw
induced higher angle of attack of the outside wing causes the excess
lift produced by the higher speed and alpha to introduce roll, a couple
has occurred and the aircraft is in an axis change from yaw only to
yaw/roll. It's a couple. Don't forget; there are complementary couplings
as well as adverse, and not all couplings result in divergence or departure.

It's really a matter of semantics and amplified explanation.
The dihedral actually stabilizes the airplane in roll and acts as you
have said.
A Cessna 195 would be one example of an airplane that will couple in yaw
without dihedral with no ill effect. A T38 however is an example of an
airplane that will couple in roll to departure if rolled at .9 mach with
a full lateral stick throw.

DH

--
Dudley Henriques

[Jay Honeck]

> I'm puzzled as to how you could be doing a solo X country and not know
> this. Did you first lesson not include "effect of controls"? what
> about your theory?

Ah, that's better. I *knew* every thread had to devolve into
recriminations sooner or later...

;-)

In my case, my instructor NEVER discussed theories about flight. He
was a stick and rudder guy, could fly anything (and did), taught me
volumes, but rarely spoke about *why* certain things happened in
flight. I guess he just figured I would learn these things when
studying for the written.

I never did learn a lot of the subtle stuff (like why a rudder input
banks the wings) until much later. I suspect Paul is in the same boat.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Mxsmanic]

Jay Honeck writes:

> In my case, my instructor NEVER discussed theories about flight. He
> was a stick and rudder guy, could fly anything (and did), taught me
> volumes, but rarely spoke about *why* certain things happened in
> flight. I guess he just figured I would learn these things when
> studying for the written.
>
> I never did learn a lot of the subtle stuff (like why a rudder input
> banks the wings) until much later. I suspect Paul is in the same boat.

Most skills can be learned in a number of ways. Many skills are taught in
rote manner, i.e., "to accomplish x, do y," or "when the aircraft does x,
react with y." This is easy and fast to learn but makes exceptions harder to
handle. Skills can also be taught by teaching theory and then letting the
student apply the theory, but this is rather tedious and slow, and the student
must have good reasoning ability in order to succeed. To address the largest
possible audience, rote learning tends to be preferred, but that does
occasionally leave competent and curious students wondering about certain
things.

[[email protected]]

On Oct 21, 7:14 am, Mxsmanic > wrote:
> Jay Honeck writes:
> > In my case, my instructor NEVER discussed theories about flight. He
> > was a stick and rudder guy, could fly anything (and did), taught me
> > volumes, but rarely spoke about *why* certain things happened in
> > flight. I guess he just figured I would learn these things when
> > studying for the written.
>
> > I never did learn a lot of the subtle stuff (like why a rudder input
> > banks the wings) until much later. I suspect Paul is in the same boat.
>
> Most skills can be learned in a number of ways. Many skills are taught in
> rote manner, i.e., "to accomplish x, do y," or "when the aircraft does x,
> react with y." This is easy and fast to learn but makes exceptions harder to
> handle. Skills can also be taught by teaching theory and then letting the
> student apply the theory, but this is rather tedious and slow, and the student
> must have good reasoning ability in order to succeed. To address the largest
> possible audience, rote learning tends to be preferred, but that does
> occasionally leave competent and curious students wondering about certain
> things.

I feel Bertie about to make an entrance,,,,, ;<)

[Paul kgyy]

On Oct 21, 4:44 am, wrote:
> I'm puzzled as to how you could be doing a solo X country and not know
> this. Did you first lesson not include "effect of controls"? what
> about your theory?
>
> Cheers

He probably did, but that was in 1967... :-(

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>> Dudley Henriques > wrote in
>> :
>>
>>> Paul kgyy wrote:
>>>> On a 3 hour cross country today I was amusing myself by flying with
>>>> rudder pedals only (all right, OK, a little yoke usage to maintain
>>>> altitude). But then I got to wondering why applying rudder
>>>> pressure causes the plane to bank. All I could think of was that
>>>> rudder usage produces asymmetric lift because one wing is somewhat
>>>> blanked by the sideways motion induced by the rudder? Also, the
>>>> rudder surface is above the plane's center of lift but I don't know
>>>> how much of a
>> factor
>>>> that is.
>>>>
>>> It's called a yaw/roll couple. As you create yaw you acellerate
>>> the
>>> outside wing which then has more lift. It raises coupling with roll
>> and
>>> you have turn.
>>>
>>
>> Gotta disagree there Dudley. While it is true, and that's what
>> happening to some degree initially, the majority of the yaw roll
>> couple in lightplanes comes from the dihedral. the wing opposite the
>> direction of yaw has a higher angle of attack and generates more lift
>> then the opposite, which now has a lower alpha. Airplanes with no
>> dihedral will still roll slightly in the direction of yaw but it's
>> nearly zilch. can prove the first statement for yourself by
>> introducing the yaw so slowly as to make the diffrence in speeds
>> insignificant. The airplane will still roll in the direction of the
>> yaw. The V1 cruise missile had no dihedral and no ailerons and was
>> easily upset for this reason. Once it was off a wings level flight
>> path it's gyros had no chance of getting it back into straight and
>> level. Swept wing airplanes can have a huge yaw roll couple because
>> as you yaw, the forward moving wing's aspect ratio becomes massive
>> just as the aft moving's wing shrinks.(transonic ones have a reverse
>> effect couple at altitude, but that's another story)
>>
>>
>> Bertie
>>
> Not so much disagreement really. What you are saying is correct. All
> these things happen.


Yep, but I think the airspeed portion is a minor one.

Technically however, the exact moment the yaw
> induced higher angle of attack of the outside wing causes the excess
> lift produced by the higher speed and alpha to introduce roll, a
> couple has occurred and the aircraft is in an axis change from yaw
> only to yaw/roll. It's a couple. Don't forget; there are complementary
> couplings as well as adverse, and not all couplings result in
> divergence or departure.
>

Yep, agreed. I stil think the speed element is insignificant in
practice. As a means of demonstration, the student can take the 172 or
whatever,and introduce some yaw smoothely and slowly whilst stopping any
roll with the ailerons.Then, leave the rudder in and nuetralise the
ailerons. With the yaw stabilised, i.e., no differnece in the speed
between the two wings, the roll will be almost as quick as if it was
introduced from co-ordinated S&L flight.


> It's really a matter of semantics and amplified explanation.
> The dihedral actually stabilizes the airplane in roll and acts as you
> have said.


Oh I know it's picking a nit and from a practical point of view is
nearly immaterial, but I'm a chronic nit-picker. Can't help it!


> A Cessna 195 would be one example of an airplane that will couple in
> yaw without dihedral with no ill effect. A T38 however is an example
> of an airplane that will couple in roll to departure if rolled at .9
> mach with a full lateral stick throw.
>




OK, the 195 is a bad example because of it's parasol element and because
it's high wing and there are issues with blanketing and what not.
One of the midwing giant model airplanes they're flying aerobatics in
nowadays would be a better example.


Actually, are you sure the 195 is zero dihedral? Most high wing
airplanes that have zero dihedral look like they have anhedral. (Swick
T-cart, f'rinstance)
It's tapered as well. so even zero dihedral on top would still give some
below!

I've flown them, BTW> Nice.


The T 38 example you're going to have to break down for me because:

a. I've not flown that class of airplane and
b. I'm full of whiskey.




Bertie

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:
> Dudley Henriques > wrote in
> :
>
>> Bertie the Bunyip wrote:
>>> Dudley Henriques > wrote in
>>> :
>>>
>>>> Paul kgyy wrote:
>>>>> On a 3 hour cross country today I was amusing myself by flying with
>>>>> rudder pedals only (all right, OK, a little yoke usage to maintain
>>>>> altitude). But then I got to wondering why applying rudder
>>>>> pressure causes the plane to bank. All I could think of was that
>>>>> rudder usage produces asymmetric lift because one wing is somewhat
>>>>> blanked by the sideways motion induced by the rudder? Also, the
>>>>> rudder surface is above the plane's center of lift but I don't know
>>>>> how much of a
>>> factor
>>>>> that is.
>>>>>
>>>> It's called a yaw/roll couple. As you create yaw you acellerate
>>>> the
>>>> outside wing which then has more lift. It raises coupling with roll
>>> and
>>>> you have turn.
>>>>
>>> Gotta disagree there Dudley. While it is true, and that's what
>>> happening to some degree initially, the majority of the yaw roll
>>> couple in lightplanes comes from the dihedral. the wing opposite the
>>> direction of yaw has a higher angle of attack and generates more lift
>>> then the opposite, which now has a lower alpha. Airplanes with no
>>> dihedral will still roll slightly in the direction of yaw but it's
>>> nearly zilch. can prove the first statement for yourself by
>>> introducing the yaw so slowly as to make the diffrence in speeds
>>> insignificant. The airplane will still roll in the direction of the
>>> yaw. The V1 cruise missile had no dihedral and no ailerons and was
>>> easily upset for this reason. Once it was off a wings level flight
>>> path it's gyros had no chance of getting it back into straight and
>>> level. Swept wing airplanes can have a huge yaw roll couple because
>>> as you yaw, the forward moving wing's aspect ratio becomes massive
>>> just as the aft moving's wing shrinks.(transonic ones have a reverse
>>> effect couple at altitude, but that's another story)
>>>
>>>
>>> Bertie
>>>
>> Not so much disagreement really. What you are saying is correct. All
>> these things happen.
>
>
> Yep, but I think the airspeed portion is a minor one.

It is minor, especially for a light GA type airplane. High performance
airplanes get into a much more complicated dynamic concerning coupling.

>
> Technically however, the exact moment the yaw
>> induced higher angle of attack of the outside wing causes the excess
>> lift produced by the higher speed and alpha to introduce roll, a
>> couple has occurred and the aircraft is in an axis change from yaw
>> only to yaw/roll. It's a couple. Don't forget; there are complementary
>> couplings as well as adverse, and not all couplings result in
>> divergence or departure.
>>
>
> Yep, agreed. I stil think the speed element is insignificant in
> practice. As a means of demonstration, the student can take the 172 or
> whatever,and introduce some yaw smoothely and slowly whilst stopping any
> roll with the ailerons.Then, leave the rudder in and nuetralise the
> ailerons. With the yaw stabilised, i.e., no differnece in the speed
> between the two wings, the roll will be almost as quick as if it was
> introduced from co-ordinated S&L flight.

As soon as you neutralize the aileron in this condition you are in
effect removing the opposing force preventing the coupling from
occurring . The airplane should instantly react to this by entering
into the couple which is consistent with your comment.
>
>
>> It's really a matter of semantics and amplified explanation.
>> The dihedral actually stabilizes the airplane in roll and acts as you
>> have said.
>
>
> Oh I know it's picking a nit and from a practical point of view is
> nearly immaterial, but I'm a chronic nit-picker.

Don't think so. In fact, you're right on with this stuff.
>
>
>> A Cessna 195 would be one example of an airplane that will couple in
>> yaw without dihedral with no ill effect. A T38 however is an example
>> of an airplane that will couple in roll to departure if rolled at .9
>> mach with a full lateral stick throw.
>>
>
>
>
>
> OK, the 195 is a bad example because of it's parasol element and because
> it's high wing and there are issues with blanketing and what not.

Well, I would agree with this in that there are blanketing effects,
actually in high wings generally.
> One of the midwing giant model airplanes they're flying aerobatics in
> nowadays would be a better example.

Could very well be.
>
>
> Actually, are you sure the 195 is zero dihedral? Most high wing
> airplanes that have zero dihedral look like they have anhedral. (Swick
> T-cart, f'rinstance)
> It's tapered as well. so even zero dihedral on top would still give some
> below!
>
> I've flown them, BTW> Nice.

If I remember right, the 195 tapers all the way out and the wing's
thickness varies as well. I believe it is a 0 dihedral wing.
>
>
> The T 38 example you're going to have to break down for me because:
>
> a. I've not flown that class of airplane and
> b. I'm full of whiskey.

Never drink and fly the T38. Pull off to the side of the taxiway and
drink, then go fly.

The 38 has a high fuselage loaded mass IYMP (inertia yaw moment
parameter) which translated into normal language :-) means that at high
rates of roll, the airplane can actually suffer a divergence on the roll
axis as a coupling takes place with yaw and a new rolling axis is formed.
This can easily be visualized when you realize that at a speed around .9
mach, the roll rate of the airplane actually doubles with the last third
of a lateral stick throw. It's possible to get very close to 720 degrees
/sec roll rate out of a clean Talon.
The airplane is actually restricted to less than a full stick throw at
..9 for this reason.
When a coupling occurrs under these conditions, the 38 will depart, as
the offset roll axis produced by the coupling is unstable due to the
high mass loading of the fuselage vs the wing area.
It is however, a source of much amusement to bounce helmets off the real
canopy in this airplane even with a restricted roll rate.
:-)
>
>
>
>
> Bertie


--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>> Dudley Henriques > wrote in
>> :
>>
>>> Bertie the Bunyip wrote:
>>>> Dudley Henriques > wrote in
>>>> :
>>>>
>>>>> Paul kgyy wrote:
>>>>>> On a 3 hour cross country today I was amusing myself by flying
>>>>>> with rudder pedals only (all right, OK, a little yoke usage to
>>>>>> maintain altitude). But then I got to wondering why applying
>>>>>> rudder pressure causes the plane to bank. All I could think of
>>>>>> was that rudder usage produces asymmetric lift because one wing
>>>>>> is somewhat blanked by the sideways motion induced by the rudder?
>>>>>> Also, the rudder surface is above the plane's center of lift but
>>>>>> I don't know how much of a
>>>> factor
>>>>>> that is.
>>>>>>
>>>>> It's called a yaw/roll couple. As you create yaw you acellerate
>>>>> the
>>>>> outside wing which then has more lift. It raises coupling with
>>>>> roll
>>>> and
>>>>> you have turn.
>>>>>
>>>> Gotta disagree there Dudley. While it is true, and that's what
>>>> happening to some degree initially, the majority of the yaw roll
>>>> couple in lightplanes comes from the dihedral. the wing opposite
>>>> the direction of yaw has a higher angle of attack and generates
>>>> more lift then the opposite, which now has a lower alpha. Airplanes
>>>> with no dihedral will still roll slightly in the direction of yaw
>>>> but it's nearly zilch. can prove the first statement for yourself
>>>> by introducing the yaw so slowly as to make the diffrence in speeds
>>>> insignificant. The airplane will still roll in the direction of the
>>>> yaw. The V1 cruise missile had no dihedral and no ailerons and was
>>>> easily upset for this reason. Once it was off a wings level flight
>>>> path it's gyros had no chance of getting it back into straight and
>>>> level. Swept wing airplanes can have a huge yaw roll couple because
>>>> as you yaw, the forward moving wing's aspect ratio becomes massive
>>>> just as the aft moving's wing shrinks.(transonic ones have a
>>>> reverse effect couple at altitude, but that's another story)
>>>>
>>>>
>>>> Bertie
>>>>
>>> Not so much disagreement really. What you are saying is correct. All
>>> these things happen.
>>
>>
>> Yep, but I think the airspeed portion is a minor one.
>
> It is minor, especially for a light GA type airplane. High performance
> airplanes get into a much more complicated dynamic concerning
> coupling.
>
>>
>> Technically however, the exact moment the yaw
>>> induced higher angle of attack of the outside wing causes the excess
>>> lift produced by the higher speed and alpha to introduce roll, a
>>> couple has occurred and the aircraft is in an axis change from yaw
>>> only to yaw/roll. It's a couple. Don't forget; there are
>>> complementary couplings as well as adverse, and not all couplings
>>> result in divergence or departure.
>>>
>>
>> Yep, agreed. I stil think the speed element is insignificant in
>> practice. As a means of demonstration, the student can take the 172
>> or whatever,and introduce some yaw smoothely and slowly whilst
>> stopping any roll with the ailerons.Then, leave the rudder in and
>> nuetralise the ailerons. With the yaw stabilised, i.e., no differnece
>> in the speed between the two wings, the roll will be almost as quick
>> as if it was introduced from co-ordinated S&L flight.
>
> As soon as you neutralize the aileron in this condition you are in
> effect removing the opposing force preventing the coupling from
> occurring . The airplane should instantly react to this by entering
> into the couple which is consistent with your comment.
>>
>>
>>> It's really a matter of semantics and amplified explanation.
>>> The dihedral actually stabilizes the airplane in roll and acts as
>>> you have said.
>>
>>
>> Oh I know it's picking a nit and from a practical point of view is
>> nearly immaterial, but I'm a chronic nit-picker.
>
> Don't think so. In fact, you're right on with this stuff.
>>
>>
>>> A Cessna 195 would be one example of an airplane that will couple in
>>> yaw without dihedral with no ill effect. A T38 however is an example
>>> of an airplane that will couple in roll to departure if rolled at .9
>>> mach with a full lateral stick throw.
>>>
>>
>>
>>
>>
>> OK, the 195 is a bad example because of it's parasol element and
>> because it's high wing and there are issues with blanketing and what
>> not.
>
> Well, I would agree with this in that there are blanketing effects,
> actually in high wings generally.
>> One of the midwing giant model airplanes they're flying aerobatics in
>> nowadays would be a better example.
>
> Could very well be.
>>
>>
>> Actually, are you sure the 195 is zero dihedral? Most high wing
>> airplanes that have zero dihedral look like they have anhedral.
>> (Swick T-cart, f'rinstance)
>> It's tapered as well. so even zero dihedral on top would still give
>> some below!
>>
>> I've flown them, BTW> Nice.
>
> If I remember right, the 195 tapers all the way out and the wing's
> thickness varies as well. I believe it is a 0 dihedral wing.

Mayb, if it is, it's the top surface only. The thickness is also
tapered, so it has dihedral on the bottom .Not as much as a 172, but
it's there all the same.
>>
>>
>> The T 38 example you're going to have to break down for me because:
>>
>> a. I've not flown that class of airplane and
>> b. I'm full of whiskey.
>
> Never drink and fly the T38. Pull off to the side of the taxiway and
> drink, then go fly.
>
> The 38 has a high fuselage loaded mass IYMP (inertia yaw moment
> parameter) which translated into normal language :-) means that at
> high rates of roll, the airplane can actually suffer a divergence on
> the roll axis as a coupling takes place with yaw and a new rolling
> axis is formed. This can easily be visualized when you realize that at
> a speed around .9 mach, the roll rate of the airplane actually doubles
> with the last third of a lateral stick throw. It's possible to get
> very close to 720 degrees /sec roll rate out of a clean Talon.
> The airplane is actually restricted to less than a full stick throw at
> .9 for this reason.
> When a coupling occurrs under these conditions, the 38 will depart, as
> the offset roll axis produced by the coupling is unstable due to the
> high mass loading of the fuselage vs the wing area.
> It is however, a source of much amusement to bounce helmets off the
> real canopy in this airplane even with a restricted roll rate.
>:-)


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

[Bertie the Bunyip[_19_]]

Mxsmanic > wrote in
:

> Jay Honeck writes:
>
>> In my case, my instructor NEVER discussed theories about flight. He
>> was a stick and rudder guy, could fly anything (and did), taught me
>> volumes, but rarely spoke about *why* certain things happened in
>> flight. I guess he just figured I would learn these things when
>> studying for the written.
>>
>> I never did learn a lot of the subtle stuff (like why a rudder input
>> banks the wings) until much later. I suspect Paul is in the same
>> boat.
>
> Most skills can be learned in a number of ways. Many skills are
> taught in rote manner, i.e., "to accomplish x, do y," or "when the
> aircraft does x, react with y." This is easy and fast to learn but
> makes exceptions harder to handle. Skills can also be taught by
> teaching theory and then letting the student apply the theory, but
> this is rather tedious and slow, and the student must have good
> reasoning ability in order to succeed. To address the largest
> possible audience, rote learning tends to be preferred, but that does
> occasionally leave competent and curious students wondering about
> certain things.
>



You are an idiot.

You don't fly and you never will.


Bertie

[Bertie the Bunyip[_19_]]

" > wrote in
oups.com:

> On Oct 21, 7:14 am, Mxsmanic > wrote:
>> Jay Honeck writes:
>> > In my case, my instructor NEVER discussed theories about flight.
>> > He was a stick and rudder guy, could fly anything (and did), taught
>> > me volumes, but rarely spoke about *why* certain things happened in
>> > flight. I guess he just figured I would learn these things when
>> > studying for the written.
>>
>> > I never did learn a lot of the subtle stuff (like why a rudder
>> > input banks the wings) until much later. I suspect Paul is in the
>> > same boat.
>>
>> Most skills can be learned in a number of ways. Many skills are
>> taught in rote manner, i.e., "to accomplish x, do y," or "when the
>> aircraft does x, react with y." This is easy and fast to learn but
>> makes exceptions harder to handle. Skills can also be taught by
>> teaching theory and then letting the student apply the theory, but
>> this is rather tedious and slow, and the student must have good
>> reasoning ability in order to succeed. To address the largest
>> possible audience, rote learning tends to be preferred, but that does
>> occasionally leave competent and curious students wondering about
>> certain things.
>
> I feel Bertie about to make an entrance,,,,, ;<)
>
>

Ta da!


Bertie

[Dudley Henriques[_2_]]

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.

--
Dudley Henriques

[Bertie the Bunyip[_19_]]

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

[Dudley Henriques[_2_]]

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.


--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> 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
>

[Dudley Henriques[_2_]]

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

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

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

[Dudley Henriques[_2_]]

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: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

[Bertie the Bunyip[_19_]]

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: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

[Dudley Henriques[_2_]]

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: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

[Bertie the Bunyip[_19_]]

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: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

[Dudley Henriques[_2_]]

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: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

[Bertie the Bunyip[_19_]]

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
>>>>>>>> :
>>>>>>>>
>>>>>>>>> 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

[Dudley Henriques[_2_]]

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
>>>>>>>>> :
>>>>>>>>>
>>>>>>>>>> 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

[[email protected]]

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
>
>
>
> - Hide quoted text -
>
> - Show quoted text -

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

[Bertie the Bunyip[_20_]]

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


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

[Bertie the Bunyip[_19_]]

wrote in news:1193070733.442941.237020
@v23g2000prn.googlegroups.com:

> 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
>>
>>
>>
>> - Hide quoted text -
>>
>> - Show quoted text -
>
> 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.
>


Ooops!

I don't think that is what he was asking either! Though both statements
you made are correct.

I think he was asking why, when you bank, the airplane also (eventually)
yaws in the same direction.
Simply put, if you bank without yaw, you slip (after the adverse yaw
thing settles down a bit) and that slip will apply a force to the fin,
coarsely dragging the nose into roughly the direction the airplane is
going.
But, as this poster points out, adverse yaw will cause it to initially
yaw in the opposite direction due to adverse yaw, and then rudder will
be required to ensure the yaw is tangential to the line of flight.
IOW the fin will knock the airplane in roughly the right direction but
you need to use your feet.


Bertie
>
>

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:

>>> 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...

Yeah, Yeager was good at that too. I've yet to hear him give George
Welch the credit he has always been due for being the first through mach
1.......but I have to admit, the Brits made some great movies about
early aviation. The old B&W's were the best I think. The films they did
on Bader and Guy Gibson were superb movies. Leslie Howard doing Mitchell
might have been a bit melodramatic I think :-))
>
>
>
>
>> 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'd say the trick here is to make damn sure it's on the "running" side
of that sin curve the day you get to fly it :-))
>
>
> 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.

I never knew that, but it would make sense. The grit in the air would
have been quite dense. I once dove a Mustang through a rain shower and
damn near stripped the paint right off it. My crew wanted to kill me
:-)
>
>
> Bertie
>


--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>
>>>> 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...
>
> Yeah, Yeager was good at that too. I've yet to hear him give George
> Welch the credit he has always been due for being the first through
> mach 1.......but I have to admit, the Brits made some great movies
> about early aviation. The old B&W's were the best I think. The films
> they did on Bader and Guy Gibson were superb movies. Leslie Howard
> doing Mitchell might have been a bit melodramatic I think :-))

Yes, they did do some good ones. as good as any done elsewhere.

>>
>>
>>
>>
>>> 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'd say the trick here is to make damn sure it's on the "running" side
> of that sin curve the day you get to fly it :-))
>>

Oh they keep it well. It's just the nature of the beast, isn't it?

>>
>> 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.
>
> I never knew that, but it would make sense. The grit in the air would
> have been quite dense. I once dove a Mustang through a rain shower and
> damn near stripped the paint right off it. My crew wanted to kill me
>:-)


Yeah, i've takne the paint off in rain lots of times.

Went through hail once. We cracked the outer panes of several screens,
took every single antenna and lamp off the airplane, holed the radome in
many places and trached on fan blade.

The noise of it was unholy. It sounded like a freight train. Crew comms
were impossible. It lasted about a minute, maybe a bit more. Not nice
but we survived it anyway. Ancient old radar wasn't worth the space it
took up.


bertie

[Dudley Henriques[_2_]]

Bertie the Bunyip wrote:
> Dudley Henriques > wrote in


> Oh they keep it well. It's just the nature of the beast, isn't it?

Those old birds can be cantankerous to a fair thee well can't they :-))

> Yeah, i've takne the paint off in rain lots of times.
>
> Went through hail once. We cracked the outer panes of several screens,
> took every single antenna and lamp off the airplane, holed the radome in
> many places and trached on fan blade.
>
> The noise of it was unholy. It sounded like a freight train. Crew comms
> were impossible. It lasted about a minute, maybe a bit more. Not nice
> but we survived it anyway. Ancient old radar wasn't worth the space it
> took up.
>
>
> bertie

Well....what would flying be like without a little "fun" once in a while
huh?? :-))))))


--
Dudley Henriques

[Bertie the Bunyip[_19_]]

Dudley Henriques > wrote in
:

> Bertie the Bunyip wrote:
>> Dudley Henriques > wrote in
>
>
>> Oh they keep it well. It's just the nature of the beast, isn't it?
>
> Those old birds can be cantankerous to a fair thee well can't they

Well, ikinda like 'em like that myself!

> :-))
>
>> Yeah, i've takne the paint off in rain lots of times.
>>
>> Went through hail once. We cracked the outer panes of several
>> screens, took every single antenna and lamp off the airplane, holed
>> the radome in many places and trached on fan blade.
>>
>> The noise of it was unholy. It sounded like a freight train. Crew
>> comms were impossible. It lasted about a minute, maybe a bit more.
>> Not nice but we survived it anyway. Ancient old radar wasn't worth
>> the space it took up.
>>
>>
>> bertie
>
> Well....what would flying be like without a little "fun" once in a
> while huh?? :-))))))

Ech, kinda past that nowadays!
That was some time ago and I haven't flown with such a poor radar in a
looong time.


Bertie

[Rich Ahrens[_2_]]

Bertie the Bunyip wrote:
> Actually, are you sure the 195 is zero dihedral? Most high wing
> airplanes that have zero dihedral look like they have anhedral. (Swick
> T-cart, f'rinstance)
> It's tapered as well. so even zero dihedral on top would still give some
> below!

He's right, Bertie. Zero. Here's a copy of an old Cessna brochure which
states so explicitly:

http://cessna195.org/classic/brochure.cfm?brochure=7&page=2

[Dana M. Hague]

On Sat, 20 Oct 2007 22:13:36 -0700, "BT" > wrote:

>Isn't interesting that entry level RC Aircraft only have rudder and elevator
>controls.. and then turn just fine.
>Funny that a full sized airplane would react the same way.

Yes, but you're not sitting *in* the R/C model, so you don't realize
that it's slipping and skidding all over the sky. Wouldn't be so
comfortable in a real airplane... though many of the older low end
ultralights had only rudder, no ailerons, either.

A high wing plane gets some dihedral effect from the wing position,
even if the actual geometric dihedral is zero. Sweep also acts as
dihedral, too.

OTOH, my Kolb has zero dihedral... and the rudder has just about nil
roll effect.

-Dana
--
--
If replying by email, please make the obvious changes.
-------------------------------------------------------------------------------
If one synchronized swimmer drowns, do the rest have to drown too?

[Bertie the Bunyip[_19_]]

Rich Ahrens > wrote in
ouse.com:

> Bertie the Bunyip wrote:
>> Actually, are you sure the 195 is zero dihedral? Most high wing
>> airplanes that have zero dihedral look like they have anhedral.
>> (Swick T-cart, f'rinstance)
>> It's tapered as well. so even zero dihedral on top would still give
>> some below!
>
> He's right, Bertie. Zero. Here's a copy of an old Cessna brochure
> which states so explicitly:
>
> http://cessna195.org/classic/brochure.cfm?brochure=7&page=2
>

Yeah, zero in the top, but since it's tapered, there can't be zero on the
bottom...


Bertie

[[email protected]]

On Oct 21, 7:13 am, "BT" > wrote:
> Isn't interesting that entry level RC Aircraft only have rudder and elevator
> controls.. and then turn just fine.
> Funny that a full sized airplane would react the same way.
>
> In a stall, you pick up the low wing with rudder, not aileron, that only
> adds adverse yaw, more drag on the low wing, and fights the rudder.
> BT

Using aileron to try to raise a dropping wing in a stall
increases the AOA on that wing and can aggravate the drop, causing a
spin. That's the real reason for using rudder.
The roll couple when we add rudder has a lot to do with
wingtip vortices. The vortex costs some lift as the air flows off the
bottom of the wing and over the tip. Sticking a wing ahead interferes
with that and can improve the lift on that side.

Dan (currently in Africa, where I find the Internet alive and
well)

[Denny]

On Oct 26, 2:25 am, Bertie the Bunyip > wrote:
> Rich Ahrens > wrote phouse.com:
>
> > Bertie the Bunyip wrote:
> >> Actually, are you sure the 195 is zero dihedral? Most high wing
> >> airplanes that have zero dihedral look like they have anhedral.
> >> (Swick T-cart, f'rinstance)
> >> It's tapered as well. so even zero dihedral on top would still give
> >> some below!
>
> > He's right, Bertie. Zero. Here's a copy of an old Cessna brochure
> > which states so explicitly:
>
> >http://cessna195.org/classic/brochure.cfm?brochure=7&page=2
>
> Yeah, zero in the top, but since it's tapered, there can't be zero on the
> bottom...
>
> Bertie

I was looking at a 195 just Wednesday - which was having a heater
installed - as I was having service on my heater at the factory... The
centerline of the wing/spar has zero dihedral... And the top surface
is tapered down to the tip as much as the bottom surface is tapered
up...

denny

[Bertie the Bunyip[_19_]]

Denny > wrote in
oups.com:

> On Oct 26, 2:25 am, Bertie the Bunyip > wrote:
>> Rich Ahrens > wrote
>> phouse.com:
>>
>> > Bertie the Bunyip wrote:
>> >> Actually, are you sure the 195 is zero dihedral? Most high wing
>> >> airplanes that have zero dihedral look like they have anhedral.
>> >> (Swick T-cart, f'rinstance)
>> >> It's tapered as well. so even zero dihedral on top would still
>> >> give some below!
>>
>> > He's right, Bertie. Zero. Here's a copy of an old Cessna brochure
>> > which states so explicitly:
>>
>> >http://cessna195.org/classic/brochure.cfm?brochure=7&page=2
>>
>> Yeah, zero in the top, but since it's tapered, there can't be zero on
>> the bottom...
>>
>> Bertie
>
> I was looking at a 195 just Wednesday - which was having a heater
> installed - as I was having service on my heater at the factory... The
> centerline of the wing/spar has zero dihedral... And the top surface
> is tapered down to the tip as much as the bottom surface is tapered
> up...


Dunna thin so.


I'll have ot look at one next time I pass one, though. Only way you
could tell for sure is to sight along the top of the wing..

I usd to fly one and it was a very nice flying airplane whichever way it
is arranged!

Bertie

[Angelo Campanella[_2_]]

BT wrote:
> Isn't interesting that entry level RC Aircraft only have rudder and elevator
> controls.. and then turn just fine.

When the rudder is applied, a skid and a turn follow. The skid is of no
consequence, but any turn rate at all is of great consequence, since tht
makes the outside wing fly faster, creating more lift, and a bank is the
result; a two-stage event where succession is important.

Sort of like turning a bicycle, where a small jink to the outside of
the intended turn is required to establish the bank needed for the turn.

> In a stall, you pick up the low wing with rudder, not aileron, that only
> adds adverse yaw, more drag on the low wing, and fights the rudder.

Aileron action, following the wright Brothers wing warping, was
intentionally symmetrical (same magnitude both sides) and all pilot
training through and after WWII were taught "Coordination"; one applied
rudder and aileron simultaneously. After WWII, civil airplane designers
acted to make life simpler for the pilot by tweaking aileron action.

The adverse yaw is caused by the extra induced* drag of a wing that is
obliged to lift more ends up also dragging more, The inbord wing is
casued to drop by an up-aileron, and any increase in parasite (non-lift)
drag is exceeded by the lack of induced drag. One day the light came on
and it was deduced that if only the inbirad aileron deflected up, the
adverse yaw would ve greately reduced if not eliminated. Sa ther wwas
born "differential movement" and belcrakx and levers were rigged such
that the inbord aileron deflected up a lot, while the outboard aileron
deflected very little.

[*"Induced" means that it is not real friction or turbulence drag, but
a new rearward force that results from a wing or aileron that is
creating extra lift.]

So today, most civit aircraft can be put into and out of gentle turns
with aileron alone, and that's what makes single-axis autopilots
(aileron only) so successful.

Angelo Campanella

[Bertie the Bunyip[_19_]]

Angelo Campanella > wrote in
:

> BT wrote:
>> Isn't interesting that entry level RC Aircraft only have rudder and
>> elevator controls.. and then turn just fine.
>
> When the rudder is applied, a skid and a turn follow. The skid is
> of no
> consequence, but any turn rate at all is of great consequence, since
> tht makes the outside wing fly faster, creating more lift, and a bank
> is the result; a two-stage event where succession is important.
>



Not true.

All the evidence you need to the contrary can be supplied by simply yawing
the airplane while holding opposite aileron, thus inducing a skid, and then
neutralising the ailerons.

the airplane will roll left and nothing to do with the differntial speed of
the wing, because there won;t be any!


Bertie
>

[Mike Noel]

....but if the wing has any significant dihedral, the 'upwind' wing will be
flying at a higher angle of attack than the 'downwind' wing, causing a roll
towards the downwind wing. The 'downwind' wing inboard section will also be
partially blanked by the fuselage which will also produce asymmetrical lift
on the wing.

--
Best Regards,
Mike

http://photoshow.comcast.net/mikenoel

"Bertie the Bunyip" > wrote in message
.. .
> Angelo Campanella > wrote in
> :
>
>> BT wrote:
>>> Isn't interesting that entry level RC Aircraft only have rudder and
>>> elevator controls.. and then turn just fine.
>>
>> When the rudder is applied, a skid and a turn follow. The skid is
>> of no
>> consequence, but any turn rate at all is of great consequence, since
>> tht makes the outside wing fly faster, creating more lift, and a bank
>> is the result; a two-stage event where succession is important.
>>
>
>
>
> Not true.
>
> All the evidence you need to the contrary can be supplied by simply yawing
> the airplane while holding opposite aileron, thus inducing a skid, and
> then
> neutralising the ailerons.
>
> the airplane will roll left and nothing to do with the differntial speed
> of
> the wing, because there won;t be any!
>
>
> Bertie
>>
>

[Bertie the Bunyip[_19_]]

"Mike Noel" > wrote in
:

> ...but if the wing has any significant dihedral, the 'upwind' wing
> will be flying at a higher angle of attack than the 'downwind' wing,
> causing a roll towards the downwind wing. The 'downwind' wing inboard
> section will also be partially blanked by the fuselage which will also
> produce asymmetrical lift on the wing.
>

Xactly.


Bertie