A very basic question

[Ramapriya]

Hi guys,

Unlike the elevators and rudder that change an aircraft's pitch and
yaw with no other secondary effect, why does the banking of wings by
the use of ailerons not just roll an aircraft but also produces a turn
(yaw)? Logically, one would expect an aircraft to keep going straight
ahead even if the pilot banked the aircraft left or right. Where does
the turning effect come from?

Is there a website you know of that can teach me such basics, without
having to bug you? :)

Cheers,

Ramapriya

[The Weiss Family]

> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>
> Cheers,
>
> Ramapriya
>

Rudder most definitely adds roll as a secondary effect.
In fact, I use rudder to momentarily keep the wings level when I'm changing
maps, etc.
At low speeds, when the ailerons are not that effective, rudder can be much
more effective.

As to the aileron, think of the relative wind on the wings.
With an aileron dropped (looking like a flap), there will be increased drag.
Of course the other one goes up, but I don't think the resultant force is
equal on both wings.
Thus, yaw results.
While it seems intuitive to me, I probably don't have the best explanation,
so can anyone else elaborate?

Adam
N7966L
Beech Super III

[Stan Prevost]

"Ramapriya" > wrote in message
om...
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>

http://www.av8n.com/how/

[Martin X. Moleski, SJ]

On 6 Nov 2004 07:37:15 -0800, (Ramapriya) wrote:

>Unlike the elevators and rudder that change an aircraft's pitch and
>yaw with no other secondary effect, why does the banking of wings by
>the use of ailerons not just roll an aircraft but also produces a turn
>(yaw)? Logically, one would expect an aircraft to keep going straight
>ahead even if the pilot banked the aircraft left or right. Where does
>the turning effect come from?

All aircraft are a series of compromises.

The location of empennage with respect to the wings,
the dihedral in the wings, the location of the wings with
respect to the thrust line and center of mass, the
airspeed of the maneuvers, and probably a dozen
other variables all affect what happens when one
control input is given.

When an aircraft equipped with unbiased ailerons is
banked, the downgoing aileron causes more drag
than the upward deflected aileron does. In Piper Cubs,
for example, this means that the high wing in a bank
tends to drag the nose AWAY from the direction of
the intended turn. In a left bank (right wing high,
left wing low), the nose tends to yaw to the right
because of the difference in drag. To make a
coordinated left turn, you need to step on the
left rudder to counteract the adverse yaw while
using the ailerons to bank to the left.

In other aircraft that have differential ailerlon trim,
the aileron will not go as far down as the other
aileron goes up. That solves the problem of
adverse yaw. Now we've got a semi-pure bank,
but the aircraft will tend to lose altitude and head
in the direction of the bank because of the loss
of lift due to the changed angle of attack of the
wings with respect to the relative airflow.

Take an extreme example: if you bank the
plane 90 degrees (knife-edge), the nose will
drop quite rapidly toward the ground because
the wings no longer produce lift against the tug
of gravity. The "lift" produced by the wings will
be toward the canopy and the aircraft will
tend to move in that direction.

In a less severe bank, there still is that component
moving the aircraft toward the canopy. If you
mix in a little elevator to maintain altitude in the
bank, the elevator will help to point the nose in
the direction of the turn without requiring rudder
to coordinate the nose with the bank.

There are other factors as well. In making any
motion from straight-and-level flight, there is a small
component introduced by shifting the plane of the
propellor from its equilibrium. It's a little bit like
moving a spinning wheel from its equilibrium.
The gyroscopic forces will act against the
turn 90 degrees away from the direction of the
turn. Physics profs like to show this force by
having someone stand on a turntable holding
a spinning wheel. By tipping the wheel in one
direction or another, they can make the turntable
spin this way and that.

The classic case of this gyroscopic force was found
in the WWI aircraft that used rotary engines. The
crankcase spun with the propellor (!). With all of that
spinning mass at the nose of the plane, very sharp turns
could be made in one direction, for good or for ill.
Modern planes with lighter propellors may not exhibit
this effect much, if at all.


DISCLAIMER:

I am not an aerodynamicist. I just play a lot with
RC aircraft. I know a great deal about accelerated
stalls and have photographs of the debris fields to
prove it. :o(

Marty

[BTIZ]

> As to the aileron, think of the relative wind on the wings.
> With an aileron dropped (looking like a flap), there will be increased
> drag.
> Of course the other one goes up, but I don't think the resultant force is
> equal on both wings.
> Thus, yaw results.

Brian, are you stating that this yaw causes the turn?, actually this is
adverse yaw and resists the turn.

Come, lets step into my flying laboratory, the Grob 103, and we'll explore
that interesting concept called adverse yaw.

BT

[BTIZ]

very basic answer..

the lift component, vertical and perpendicular to the wings, in a bank is
now pointed off to one side of straight up (relative to earth), there are
now two components to the lift vector, horizontal and vertical, the vertical
lift assists in maintaining altitude, the horizontal component works the
turning tendency.

That is why in a steep turn, more elevator back pressure is required. You
have reduced the vertical component of lift to maintain altitude by giving
some of the lift to the horizontal component. You need to increase the AOA
on the wings to make more lift, to maintain the required amount of vertical
component to maintain the altitude.

again, a very basic answer..
step into the flying laboratory for further exploration of this concept

BT

"Ramapriya" > wrote in message
om...
> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>
> Cheers,
>
> Ramapriya
>

[James Robinson]

Ramapriya wrote:
>
> ... why does the banking of wings by the use of ailerons not just
> roll an aircraft but also produces a turn (yaw)?

Simply stated, when an aircraft is in level flight, the lift of the
wings works directly against gravity. When an aircraft rolls one
direction or the other, the lift of the wings rolls away from vertical,
remaining at 90 degrees to the wings. This means only part of the lift
works against gravity. The rest causes the aircraft to swing away from
straight flight. It is somewhat akin to the effect of banking on a race
track.

[jls]

"James Robinson" > wrote in message
...
> Ramapriya wrote:
> >
> > ... why does the banking of wings by the use of ailerons not just
> > roll an aircraft but also produces a turn (yaw)?
>
> Simply stated, when an aircraft is in level flight, the lift of the
> wings works directly against gravity. When an aircraft rolls one
> direction or the other, the lift of the wings rolls away from vertical,
> remaining at 90 degrees to the wings. This means only part of the lift
> works against gravity. The rest causes the aircraft to swing away from
> straight flight. It is somewhat akin to the effect of banking on a race
> track.

Fair enough. The turn is caused by the horizontal component of lift.

[kontiki]

The turn occurs because as you roll into bank, the lift vector now
has a horizontal component which will pull you in the direction of
the bank. Think of a string suspending the wing straight up (the
lift vector for level flight). Now think of the string being pulled
sideways slightly as well as up. This will pull the aircaft in the
direction of the pull... or lift vector... which now has a horizontal
component.

The rudder is used to coordinate the turn only.

You could fly along level with a slight bank angle with no turn
(aka a "slip") if you applied opposite rudder... enough to counteract
the horisontal lift component. This will only work for a limited bank
angle however.

Ramapriya wrote:

> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>
> Cheers,
>
> Ramapriya
>

[Peter Duniho]

"Ramapriya" > wrote in message
om...
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)?

The simple answer is that, theoretically, the ailerons act exactly as you
would think. That is, a turn is not caused by a change in bank.

A more complicated answer is that since the "center of lift" is ahead of the
"center of gravity", having the lift vector tilted to one side or the other
by bank does pull the nose of the airplane around a bit, inducing a turn.

An even more complicated answer points out that the ailerons themselves
create increased drag on the raised wing and reduced drag on the lowered
wing, which creates a yaw opposite in direction to the intended turn.

In reality, the ailerons and rudder are BOTH very necessary to accomplish an
efficient turn. Either can be used by themselves to change aircraft
heading, but neither is very effective alone in most airplanes.

As far as the elevator and rudder having "no other secondary effect", that's
not true. Pretty much every control on an airplane has a secondary effect.
Use of rudder will induce roll, for example, while use of the elevator can
induce yaw (mostly due to propeller effects).

> [...]
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)

There are many. The one already provided by Stan's reply is one of my
favorites. There are also several good books on the topic, including the
FAA's own flight training manuals (available for download from their web
site somewhere, but I don't have a link handy) and a book called
"Aerodynamics for Naval Aviators".

Pete

[Andrew Sarangan]

(Ramapriya) wrote in news:30a8759c.0411060737.6b82f9c3
@posting.google.com:

> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>
> Cheers,
>
> Ramapriya
>


When you bank, you create a horizontal component of lift. This will pull
the airplane to fly sideways. The natural weathervaning effect of the
airplane will steer the nose into the relative wind. You can help that
effect by adding rudder.

This is a good question. Even most instructors do not know the answer to
this questions.


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[Andrew Sarangan]

" jls" > wrote in news:758jd.40492$T_.36816
@bignews4.bellsouth.net:

>
> "James Robinson" > wrote in message
> ...
>> Ramapriya wrote:
>> >
>> > ... why does the banking of wings by the use of ailerons not just
>> > roll an aircraft but also produces a turn (yaw)?
>>
>> Simply stated, when an aircraft is in level flight, the lift of the
>> wings works directly against gravity. When an aircraft rolls one
>> direction or the other, the lift of the wings rolls away from vertical,
>> remaining at 90 degrees to the wings. This means only part of the lift
>> works against gravity. The rest causes the aircraft to swing away from
>> straight flight. It is somewhat akin to the effect of banking on a race
>> track.
>
> Fair enough. The turn is caused by the horizontal component of lift.
>
>
>

Sure, but that still does not explain why the airplane turns. A horizontal
component of lift will make the airplane side-slip, not turn. It is the
stability (weathervane effect) that makes the airplane turn.

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[Dudley Henriques]

"BTIZ" > wrote in message
news:K97jd.86842$bk1.136@fed1read05...
>> As to the aileron, think of the relative wind on the wings.
>> With an aileron dropped (looking like a flap), there will be
>> increased drag.
>> Of course the other one goes up, but I don't think the resultant
>> force is equal on both wings.
>> Thus, yaw results.
>
> Brian, are you stating that this yaw causes the turn?, actually this
> is adverse yaw and resists the turn.
>
> Come, lets step into my flying laboratory, the Grob 103, and we'll
> explore that interesting concept called adverse yaw.
>
> BT
Inside rudder will most definitely produce bank which will produce turn
exactly as Brian said it would. There is a difference between adverse
and complimentary yaw. Actually, there will be no adverse yaw if inside
rudder alone is used to induce complimentary yaw. Only aileron
application into a bank with no inside rudder will produce adverse yaw.
If complimentary yaw (inside rudder) is used with no aileron, the speed
difference between the retreating inside wing and the forward moving
outside wing will cause bank, which will be a direct secondary result of
the complimentary yaw being produced.
In other words, insider rudder will most definitely produce bank as a
secondary effect and as such will produce turn...assuming no anti turn
control input is present.
Dudley Henriques
International Fighter Pilots Fellowship
for email; take out the trash

[Greg Butler]

"Ramapriya" > wrote in message
om...
Where does
> the turning effect come from?

The most basic (maybe too basic) answer is generally this: When you bank,
the lift is at an angle, not straight vertical. That angle pushes it the
plane to the side as well as up.

[Mike Rhodes]

On Sat, 6 Nov 2004 10:41:12 -0800, "Peter Duniho"
> wrote:

>"Ramapriya" > wrote in message
om...
>> Unlike the elevators and rudder that change an aircraft's pitch and
>> yaw with no other secondary effect, why does the banking of wings by
>> the use of ailerons not just roll an aircraft but also produces a turn
>> (yaw)?
>
>The simple answer is that, theoretically, the ailerons act exactly as you
>would think. That is, a turn is not caused by a change in bank.

In level flight, the wings are generating 1g of lift, equivalent to
the weight of the aircraft and all occupants inside. If this lift
vector is rotated by the ailerons then it will point in the direction
of the rotation, and therefore force the aircraft to change its
direction of flight, and therefore to turn.

And there will a corresponding loss of lift against gravity; all
simply calculated by geometric functions of sine and cosine. So the
aircraft will begin to descend, as it turns.

>
>A more complicated answer is that since the "center of lift" is ahead of the
>"center of gravity", having the lift vector tilted to one side or the other
>by bank does pull the nose of the airplane around a bit, inducing a turn.

If the center of lift actually was ahead of the center of gravity then
the aircraft would loop nose-up, so it isn't. They are aligned. But
it is the acceleration in the direction of the rotated lift vector
which changes the direction of the airflow around the aircraft. So
the airfoils at the tail force the airplanes nose to point into the
direction of the changing wind.

This also changes the direction of the lift vector to the new
location, which is actually the same location, and it is known as the
center point of the circle the airplane is drawing out in 3-d space.
The circle is actually the bottom of a cone, with the cone drawn by
the lift vector of the aircraft. The tighter the turn then the
flatter the cone. If there is no turn then the cone is not a cone but
a flat plane instead.

In other words, the aircraft in a turn is flying in a circle, instead
of just accelerating sideways and retaining its former forward
velocity, which it does not do. The changing wind over the airfoils
rotate the aircraft into flying into a circle.

>
>An even more complicated answer points out that the ailerons themselves
>create increased drag on the raised wing and reduced drag on the lowered
>wing, which creates a yaw opposite in direction to the intended turn.

More or less. A lowered aileron has the increased drag, while a
raised aileron has less drag. This will pull the nose around opposite
from the direction of expected bank.
Adverse yaw is the ailerons acting in place of the rudder, and it
prevents the aircraft from lining perfectly into the wind.

But once the aircraft is banked then the aircraft will turn. The
aircraft turns because it is banked.

A banked aircraft will not turn if, and only if, the wing is not
generating lift. A wing will not generate lift if its angle of attack
is so controlled by the horizontal stabilizer.

One other note, the aircraft will lose lift and so descend as it banks
into a turn. But as it descends, the wings will regain upward airflow
and restore the lift lossed. This stops the downward acceleration,
with the airplane having reached its terminal velocity. But the lift,
and the loads on the wing, have increased just from the aircraft going
into a bank; even if adjustments have not been made for level flight.

(I think this is ~correct. Pretty sure.)

--Mike

[bryan chaisone]

"The Weiss Family" > wrote in message >...
> > Unlike the elevators and rudder that change an aircraft's pitch and
> > yaw with no other secondary effect, why does the banking of wings by
> > the use of ailerons not just roll an aircraft but also produces a turn
> > (yaw)? Logically, one would expect an aircraft to keep going straight
> > ahead even if the pilot banked the aircraft left or right. Where does
> > the turning effect come from?
> >
> > Is there a website you know of that can teach me such basics, without
> > having to bug you? :)
> >
> > Cheers,
> >
> > Ramapriya
> >
>
> Rudder most definitely adds roll as a secondary effect.
> In fact, I use rudder to momentarily keep the wings level when I'm changing
> maps, etc.
> At low speeds, when the ailerons are not that effective, rudder can be much
> more effective.
>
> As to the aileron, think of the relative wind on the wings.
> With an aileron dropped (looking like a flap), there will be increased drag.
> Of course the other one goes up, but I don't think the resultant force is
> equal on both wings.
> Thus, yaw results.
> While it seems intuitive to me, I probably don't have the best explanation,
> so can anyone else elaborate?
>
> Adam
> N7966L
> Beech Super III

Because when the wing is level, the lift is up. When the wing is
banked to the right, the lift is also tilted to the right pulling the
plane in the direction. Same for the left.

Bryan

[Maule Driver]

I was always under the impression that in most light a/c, the dominate
rolling effect from 'inside' rudder is the result of dihedral (or
alternatively, sweep back). RC modelers are pretty adept at setting up
aircraft for 'pure' yaw from rudder input - no dihedral, symmetrical layout,
etc. Or setting up aircraft to bank and turn without ailerons - lots of
didedral.

Though I'd agree that the "forward motion of the outside wing" explanation
accurately predicts the rolling effect from rudder input that occurs on most
a/c - which is ok for training purposes.

"Dudley Henriques" >
snip
> If complimentary yaw (inside rudder) is used with no aileron, the speed
> difference between the retreating inside wing and the forward moving
> outside wing will cause bank, which will be a direct secondary result of
> the complimentary yaw being produced.
> In other words, insider rudder will most definitely produce bank as a
> secondary effect and as such will produce turn...assuming no anti turn
> control input is present.
> Dudley Henriques
> International Fighter Pilots Fellowship
> for email; take out the trash
>
>

[Dudley Henriques]

"Maule Driver" > wrote in message
om...
>I was always under the impression that in most light a/c, the dominate
> rolling effect from 'inside' rudder is the result of dihedral (or
> alternatively, sweep back). RC modelers are pretty adept at setting
> up
> aircraft for 'pure' yaw from rudder input - no dihedral, symmetrical
> layout,
> etc. Or setting up aircraft to bank and turn without ailerons - lots
> of
> didedral.
>
> Though I'd agree that the "forward motion of the outside wing"
> explanation
> accurately predicts the rolling effect from rudder input that occurs
> on most
> a/c - which is ok for training purposes.

I would agree with this completely. Dihedral contributes heavily to the
lateral stability of the aircraft if sideslip is present to be sure. The
prime contribution of dihedral is in the development of a stable rolling
moment with sideslip, which is consistent with what most of us are
saying.
The problem with answering many questions in aerodynamics is that there
isn't one single example or answer that will suffice.
(Lift is a PRIME example of this. ) Anyone trying to explain lift in a
simple sentence will find a slew of missing data soon to follow :-) The
problem in aerodynamics is that in much of what is happening, several
explanations are in force physically together at one instant in time.
The way we look at dihedral in the flight test community is primarily as
it's effect on the lateral stability scenario which relates with
sideslip present to relative wind, differential in angle of attack,
changes in lift raising a windward wing producing stability.
I think we're both on the same page, and dealing with the same effect
since all of what we're discussing is present in complimentary yaw IF
dihedral is present.
Now, if we inject an airplane into this equation like a Cessna 195 for
example.......... :-))))
Dudley Henriques
International Fighter Pilots Fellowship
for email; take out the trash

[Jim Harper]

(Ramapriya) wrote in message >...
> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>
> Cheers,
>
> Ramapriya
>

Alas, Ramapriya, it is far more complex than that! First of all, the
rudder causes not only yaw, but by virtue of the yaw accelerating the
outside wing and effectively increasing lift, causes bank toward the
inside of the turn.

The ailerons cause both roll AND yaw...but counterintuitively, the yaw
is to the outside of the turn. That is because the creation of lift
also creates drag. And when you use the ailerons to bank, you are
increasing the lift on the outside wing...and therefore yawing toward
the "outside" of the turn. The rudder largely is used to counter that
force.

And none of that is why an airplane turns. The true cause of the turn
is...well, we need to look at an airplane in our mind's eye...picture
it in level flight. The force of gravity is offset by the force of
lift...generated by the wings. We can say that there is a downward
vector...gravity...and an upward vector...lift, which is perpendicular
to the airplane's wing. Now, let us bank the airplane. The lift vector
is still perpendicular to the airplane's wing, but now it is directed
somewhat toward the inside of the bank. And the airplane therefore
turns that way...is pulled that way, if you will. Oh, and yes, since
the lift vector is directed toward the inside of the turn, the amount
of lift to counteract gravity is decreased...and the airplane will
descend unless something is done...usually the addition of power or an
increase in the angle of attack...increases the antigravity portion of
the lift vector.

That will either help or totally confuse you. Feel free to email me
for a dialog.

Jim

[tony roberts]

I strongly suggest that you visit

www.whittsflying.com

It will answer pretty much any flying question that you have.

I also suggest that you go for a discovery flight - sounds like you are
moree than ready :)

Of course, you are also still welcome to ask here.

Tony

--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE





In article >,
(Ramapriya) wrote:

> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>
> Cheers,
>
> Ramapriya
>

[Kevin]

"The Weiss Family" > wrote in message >...
> Thus, yaw results.
> While it seems intuitive to me, I probably don't have the best explanation,
> so can anyone else elaborate?
>

Tilting of the lift vector also results in a turn.

[Peter Duniho]

"Mike Rhodes" > wrote in message
...
> [...signed...]
> (I think this is ~correct. Pretty sure.)


You ought to *know* before you post, I guess.

With respect to your specific comments:

>>The simple answer is that, theoretically, the ailerons act exactly as you
>>would think. That is, a turn is not caused by a change in bank.
>
> In level flight, the wings are generating 1g of lift, equivalent to
> the weight of the aircraft and all occupants inside. If this lift
> vector is rotated by the ailerons then it will point in the direction
> of the rotation, and therefore force the aircraft to change its
> direction of flight, and therefore to turn.

Wrong. In the theoretical case I describe (which isn't the reality case
anyway), banking would simply cause the airplane to sideslip sideways,
without any turn occurring.

The "1g of lift" stuff is irrelevant, except inasmuch as there IS lift (a
force) that is redirected sideways.

>>A more complicated answer is that since the "center of lift" is ahead of
>>the >>"center of gravity", having the lift vector tilted to one side or
>>the other
>>by bank does pull the nose of the airplane around a bit, inducing a turn.
>
> If the center of lift actually was ahead of the center of gravity then
> the aircraft would loop nose-up, so it isn't. They are aligned.

Wrong, again. The center of lift is actually behind the center of gravity
(I screwed up in my original post). The horizontal stabilizer balances out
the difference in force to prevent the nose from dropping as a result of the
difference.

To revist my original post, the correct statement would have been "since the
'center of lift' is behind the 'center of gravity', having the lift vector
tilted to one side or the other by bank does pull the nose of the airplane
around a bit, inducing a turn *opposite to that intended*."

I apologize for resulting confusion, but the fact remains that your
statement is entirely incorrect.

> [...]
>>An even more complicated answer points out that the ailerons themselves
>>create increased drag on the raised wing and reduced drag on the lowered
>>wing, which creates a yaw opposite in direction to the intended turn.
>
> More or less. A lowered aileron has the increased drag, while a
> raised aileron has less drag. This will pull the nose around opposite
> from the direction of expected bank.

Heh...one of the few things you get right, and it's exactly what I wrote.

> Adverse yaw is the ailerons acting in place of the rudder, and it
> prevents the aircraft from lining perfectly into the wind.

"In place of"? Uh, okay...I guess you could say it that way.

> But once the aircraft is banked then the aircraft will turn. The
> aircraft turns because it is banked.

No, it does not. Any turn as a result of bank is actually due to other
design features of the airplane, such as dihedral and a vertical stabilizer.

Pete

[G.R. Patterson III]

Ramapriya wrote:
>
> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?

The wings of an airplane produce lift. When the aircraft is in level flight, this
lift is pointed straight up and pulls up against gravity. When you bank the plane,
the lift now points partially in the direction of bank and pulls the plane in that
direction.

Someone mentioned the book "Stick and Rudder" some time back. That's one book you
could buy. There are many others that you could buy instead. I don't know of much on
the web for free.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.

[Slick]

Go to howstuffworks.com and search for airplane wing or airplane or
something like that and you will find a detailed description with pictures.
"Ramapriya" > wrote in message
om...
> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?
>
> Is there a website you know of that can teach me such basics, without
> having to bug you? :)
>
> Cheers,
>
> Ramapriya
>




----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
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[BTIZ]

Dudely.. he said turning by banking only.. he said nothing of "inside
rudder"
at least not the way I read it

BT

"Dudley Henriques" > wrote in message
ink.net...
>
> "BTIZ" > wrote in message
> news:K97jd.86842$bk1.136@fed1read05...
>>> As to the aileron, think of the relative wind on the wings.
>>> With an aileron dropped (looking like a flap), there will be increased
>>> drag.
>>> Of course the other one goes up, but I don't think the resultant force
>>> is equal on both wings.
>>> Thus, yaw results.
>>
>> Brian, are you stating that this yaw causes the turn?, actually this is
>> adverse yaw and resists the turn.
>>
>> Come, lets step into my flying laboratory, the Grob 103, and we'll
>> explore that interesting concept called adverse yaw.
>>
>> BT
> Inside rudder will most definitely produce bank which will produce turn
> exactly as Brian said it would. There is a difference between adverse and
> complimentary yaw. Actually, there will be no adverse yaw if inside rudder
> alone is used to induce complimentary yaw. Only aileron application into a
> bank with no inside rudder will produce adverse yaw.
> If complimentary yaw (inside rudder) is used with no aileron, the speed
> difference between the retreating inside wing and the forward moving
> outside wing will cause bank, which will be a direct secondary result of
> the complimentary yaw being produced.
> In other words, insider rudder will most definitely produce bank as a
> secondary effect and as such will produce turn...assuming no anti turn
> control input is present.
> Dudley Henriques
> International Fighter Pilots Fellowship
> for email; take out the trash
>
>

[Dudley Henriques]

"BTIZ" > wrote in message
news:Lphjd.90058$bk1.21776@fed1read05...
> Dudely.. he said turning by banking only.. he said nothing of "inside
> rudder"
> at least not the way I read it
>
> BT

I admit the question is a little vague to say the least. I think I might
have got caught up in that "turn"(yaw) thing and read it to mean
complimentary yaw producing turn as a secondary effect.
I read it as asking several things that were not exactly correct in
premise to begin with!

For example;
"Unlike the elevators and rudder that change an aircraft's pitch and
yaw with no other secondary effect,"

I have a bit of a problem with this premise before even getting into the
"question"
:-)
Then we have this;
"why does the banking of wings by
the use of ailerons not just roll an aircraft but also produces a turn
(yaw)? "

I read his context as aileron being used and producing turn which in the
turn (inside context) would be complimentary yaw.....which of course
wouldn't be the secondary effect of using aileron to begin
with.........are you following this........cause I'm getting lost!!!
:-)))
The parenthesis (yaw) opens up a whole deck of cards since banking the
airplane with just aileron would produce adverse yaw; not complimentary
yaw, and it will also as a secondary effect after adverse yaw had
stabilized, produce turn if not held back with anti turn controls. It's
puzzling the way he worded it really.
I'm not sure really what he was asking at this point!! :-)

Anyway, the answer for uncoordinated turn entry using various isolated
control inputs would be if aileron alone....adverse yaw followed by turn
after stabilization and vector split;
and inside rudder alone; turn as bank is introduced as the secondary and
the lift vector splits.
You are completely right of course about dihedral effect!
Anyway....I think I'll leave this for you guys to play with. I'm going
to bed!!
:-)
Have a good one,
Dudley

[Ramapriya]

"Peter Duniho" > wrote in message >...

> There are many. The one already provided by Stan's reply is one of my
> favorites. There are also several good books on the topic, including the
> FAA's own flight training manuals (available for download from their web
> site somewhere, but I don't have a link handy) and a book called
> "Aerodynamics for Naval Aviators".
>
> Pete

I love jsd's site too, and have condensed all those chapters into two
Word files (in case someone is interested!). But I wish Denker had
also written the stuff for a non-aviator like me in mind. For example,
he's written loads on trim but till this day, I don't know what
exactly trimming is and how it physically works :(

Ramapriya

[Peter Duniho]

"Ramapriya" > wrote in message
om...
> I love jsd's site too, and have condensed all those chapters into two
> Word files (in case someone is interested!). But I wish Denker had
> also written the stuff for a non-aviator like me in mind. For example,
> he's written loads on trim but till this day, I don't know what
> exactly trimming is and how it physically works :(

Well, trimming isn't complicated. But there are numerous methods for
actually *accomplishing* it, so perhaps that's why Denker sort of just
assumes you're familiar with the concept and doesn't get into how it
"physically works".

That is, the basic concept is simple: "trimming" simply means to set a
particular control (the "trim"...generally you may have elevator, rudder, or
aileron trim or any combination of the three, though I don't doubt there's
at least one unusual aircraft out there that has yet another possibility I'm
not aware of) so that instead of the pilot having to hold a particular
control input, the "trim" holds it for him.

So, for elevator trim (the most common type), once the pilot has selected a
pitch attitude for a climb (for example), along with the desired power
setting (often full power), he can then set the elevator trim to hold the
elevator control input at that particular pitch attitude.

It gets complicated when you start talking about each specific trim
mechanism, since they all have subtle differences in exactly how they
accomplish that "hold the control input" action, as well as effects of power
or airspeed changes on the effect of the trim.

As an example, look at elevator trim:

Generally speaking, elevator trim can be thought of as "setting" an
airspeed, since for a given power setting, airspeed varies precisely with
pitch attitude. A further generalization is that changes in power do NOT
actually change the "trimmed airspeed". That is, for a given trim setting,
increasing power will result in the nose pitching up and decreasing power
will result in the nose pitching down, with the airspeed remaining constant
in both cases.

For some aircraft, the airspeed literally remains constant. For others, you
will actually see slight variations in airspeed. But regardless, any
variations are almost always so small that you can still think of setting
airspeed rather than a specific trim setting. Since trim doesn't really set
a pitch attitude either (except for a given power setting), it's not like
there's really a more useful paradigm to use.

Just as an example of one elevator trim mechanism: in most of the
single-engine Cessnas (and maybe their piston twins, but I don't know those
airplanes well enough to say), elevator trim is accomplished through the use
of a moveable "trim tab" mounted on the trailing edge of the elevator.
There's a wheel in the cockpit that moves this trim tab up and down. When
the trim tab moves up, it exerts a downward force on the elevator and when
the trim tab moves down, it exerts an upward force on the elevator
(aerodynamically, in the exact same way that the elevator itself changes the
horizontal stabilizer's up or down force). The trim tab is relatively
small, so that by pushing down on the elevator, the net effect is to cause
the horizontal stabilizer to create an upward force (nose down pitch), just
as if the pilot had pushed forward on the yoke to deflect the elevator
downward.

Anyway, other aviation references will provide much more detailed
information on that sort of thing. "Stick and Rudder" will give you a good
pilot's view of things, while the "Aerodynamics for Naval Aviators" delves
more deeply into the actual mechanics of flight (naturally).

Pete

[Cub Driver]

On 6 Nov 2004 07:37:15 -0800, (Ramapriya) wrote:

>why does the banking of wings by
>the use of ailerons not just roll an aircraft

Drag. The lower wing and its raised aileron produce more drag than the
upper with with its lowered aileron. There are little sketches in the
flying texts showing why this is the case. Would it be possible to
design ailerons that eliminated the difference? Maybe.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

Warbird's Forum www.warbirdforum.com
Piper Cub Forum www.pipercubforum.com
the blog www.danford.net

[Cub Driver]

On Sun, 07 Nov 2004 05:09:36 GMT, "Dudley Henriques"
> wrote:

>"why does the banking of wings by
>the use of ailerons not just roll an aircraft but also produces a turn

He wants to know why his pilot can't simply do rolls around the
plane's longitudinal axis.

Perhaps it would help to know what inputs are necessary to make such a
roll? If you are rolling to your left, do you apply right rudder?

all the best -- Dan Ford
email: (put Cubdriver in subject line)

Warbird's Forum www.warbirdforum.com
Piper Cub Forum www.pipercubforum.com
the blog www.danford.net

[Hilton]

Andrew Sarangan wrote:

> Sure, but that still does not explain why the airplane turns. A horizontal
> component of lift will make the airplane side-slip, not turn. It is the
> stability (weathervane effect) that makes the airplane turn.

By definition, the 'weathervane effect' occurs because air exerts more
pressure on one side of the object (aircraft) than the other - same
definition as slipping. Therefore, are you are asserting that an aircraft
turns because it is slipping? More over, it will only turn if it is
slipping?

Hilton

[Martin X. Moleski, SJ]

On Sun, 07 Nov 2004 06:13:43 -0500, Cub Driver
> wrote:

>He wants to know why his pilot can't simply do rolls around the
>plane's longitudinal axis.

>Perhaps it would help to know what inputs are necessary to make such a
>roll? If you are rolling to your left, do you apply right rudder?

It depends on the aircraft you're flying. I imagine jets
require very little "top rudder" to do an axial roll. Some
of the hot aerobatic planes scarcely allow time for
rudder input, I imagine.

Here's the sequence I learned for a slow, axial roll:

Input aileron. Hold it through the maneuver for a
steady roll rate.

Input "top rudder" as the plane reaches knife-edge.
If rolling to the left, right rudder will be on top first.

Back to neutral on rudder as the plane goes
inverted. Push on the stick to maintain level
flight upside-down.

Release the pressure on the elevator.

Input top rudder as the plane reaches knife-edge.
In the example of rolling to the left, this will now
be left rudder.

Release the pressure on the rudder as the
plane rolls upright.

Apply any necessary backpressure to maintain
level flight.

This is so much easier to do than it is to explain
in writing.

To do a rolling circle, add in appropriate inputs
toward the center of the circle as needed. To
do the rolls in a straight line, be careful to get
the inputs in at the right time.

Marty

[Maule Driver]

We are on the same page. The analogy with describing lift is spot on.

Never flown a 195 but I bet it rolls a bit with rudder too. I'd bet it has
a little to do with fuselage blanking the trailing wing lift a bit while
the leading wing works a little better. But all of that is a wild ass
guess. I'll have to ask our resident 195 guy how it responds to rudder.

Thanks.
"Dudley Henriques" > wrote in message
ink.net...
>
> "Maule Driver" > wrote in message
> om...
> >I was always under the impression that in most light a/c, the dominate
> > rolling effect from 'inside' rudder is the result of dihedral (or
> > alternatively, sweep back). RC modelers are pretty adept at setting
> > up
> > aircraft for 'pure' yaw from rudder input - no dihedral, symmetrical
> > layout,
> > etc. Or setting up aircraft to bank and turn without ailerons - lots
> > of
> > didedral.
> >
> > Though I'd agree that the "forward motion of the outside wing"
> > explanation
> > accurately predicts the rolling effect from rudder input that occurs
> > on most
> > a/c - which is ok for training purposes.
>
> I would agree with this completely. Dihedral contributes heavily to the
> lateral stability of the aircraft if sideslip is present to be sure. The
> prime contribution of dihedral is in the development of a stable rolling
> moment with sideslip, which is consistent with what most of us are
> saying.
> The problem with answering many questions in aerodynamics is that there
> isn't one single example or answer that will suffice.
> (Lift is a PRIME example of this. ) Anyone trying to explain lift in a
> simple sentence will find a slew of missing data soon to follow :-) The
> problem in aerodynamics is that in much of what is happening, several
> explanations are in force physically together at one instant in time.
> The way we look at dihedral in the flight test community is primarily as
> it's effect on the lateral stability scenario which relates with
> sideslip present to relative wind, differential in angle of attack,
> changes in lift raising a windward wing producing stability.
> I think we're both on the same page, and dealing with the same effect
> since all of what we're discussing is present in complimentary yaw IF
> dihedral is present.
> Now, if we inject an airplane into this equation like a Cessna 195 for
> example.......... :-))))
> Dudley Henriques
> International Fighter Pilots Fellowship
> for email; take out the trash
>
>
>
>

[Andrew Sarangan]

"Hilton" > wrote in
ink.net:

> Andrew Sarangan wrote:
>
>> Sure, but that still does not explain why the airplane turns. A
>> horizontal component of lift will make the airplane side-slip, not
>> turn. It is the stability (weathervane effect) that makes the
>> airplane turn.
>
> By definition, the 'weathervane effect' occurs because air exerts more
> pressure on one side of the object (aircraft) than the other - same
> definition as slipping. Therefore, are you are asserting that an
> aircraft turns because it is slipping? More over, it will only turn
> if it is slipping?
>
> Hilton
>
>
>

Think of the space shuttle. If you fire rockets horizontal to the flight
path, the shuttle will slide sideways. It will not turn the nose towards
the direction of travel. An airplane turns because it wants to point the
nose into the relative wind.

Posted Via Usenet.com Premium Usenet Newsgroup Services
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[Dudley Henriques]

"Cub Driver" > wrote in message
...
> On Sun, 07 Nov 2004 05:09:36 GMT, "Dudley Henriques"
> > wrote:
>
>>"why does the banking of wings by
>>the use of ailerons not just roll an aircraft but also produces a turn
>
> He wants to know why his pilot can't simply do rolls around the
> plane's longitudinal axis.
>
> Perhaps it would help to know what inputs are necessary to make such a
> roll? If you are rolling to your left, do you apply right rudder?

A slow roll is extremely difficult to visualize with verbal
interpretation only.
The best way to describe what you are asking..say a slow roll to the
left is to first understand that a slow roll isn't exactly a roll dead
on the longitudinal axis as the axis relates to a "level" roll. The
visualization of a slow roll to the left can be made by envisioning a
reverse capital letter D, which naturally isn't in my little bag of
computer symbols, so a roll to the right is much easier to visualize. So
to the right, you can envision a capital letter D.
The reason for the D shape is because to do the roll properly, you will
have to pass through exact inverted at the airplane's level flight
inverted attitude to keep altitude in check during the roll. The
tightness of the D shape will depend on the wing design of the airplane
you're flying. A symmetrical wing on a Pitts, or an Extra for example
will be a much tighter D than say a Citabria with a high lift cambered
wing.
Anyway, the vertical line of the D represents the raising of the nose
during the first half of the roll until right past the full inverted
position. At that point, the nose must again be lowered to a normal
level flight attitude, and this is represented by the curve on the D
returning the airplane back to upright level flight attitude.
The roll can be done with inside rudder at roll initiation or without
insider rudder. When flying airshow demonstrations, I seldom used inside
rudder with inside aileron when initiating a slow roll. Reason for this
is that adverse yaw will pull the nose outside, which if caught exactly
right, will result in your going straight to the required top rudder you
need to carry you through knife edge at the right spot on the roll axis,
and if it's a point roll, you don't have to change feet at the first
point, but to do this requires a fairly fast roll rate, so it's aircraft
specific. In the P51 for example, the roll rate isn't fast enough to use
the adverse yaw generated so that it negates the normal inside rudder
you need to counter that adverse yaw, which in turn means you enter with
aileron and insider rudder, and immediately go to top rudder as soon as
a positive coordinated roll entry has been accomplished.
Back to the Pitts, entering into the first knife edge, you have steady
inside aileron and have blended in enough positive pitch with elevator
to climb the vertical D line nose high for the inverted level
transition.You hold top rudder through knife edge and then start
blending in whatever forward stick you need to pint the nose at level
inverted. You're also blending off the top rudder at this point at a
rate that will neutralize it passing through inverted. Stick at this
point is forward and in the corner for aileron and elevator blending.
Passing through inverted, you switch to opposite side top rudder and
reverse the procedure, blending in past the second knife edge, as you
come back down the backside of the D curve whatever back pressure you
need to return the nose to normal level flight attitude.
What I've just described is much better learned in actual flight, where
a slow roll can be done by rote, then understood
afterwards...........and in far less words to boot :-)
Dudley Henriques
International Fighter Pilots Fellowship
for email; take out the trash

[Dudley Henriques]

"Dudley Henriques" > wrote in message
ink.net...
>
> "Cub Driver" > wrote in message
> ...
>> On Sun, 07 Nov 2004 05:09:36 GMT, "Dudley Henriques"
>> > wrote:
>>
>>>"why does the banking of wings by
>>>the use of ailerons not just roll an aircraft but also produces a
>>>turn
>>
>> He wants to know why his pilot can't simply do rolls around the
>> plane's longitudinal axis.
>>
>> Perhaps it would help to know what inputs are necessary to make such
>> a
>> roll? If you are rolling to your left, do you apply right rudder?
>
> A slow roll is extremely difficult to visualize with verbal
> interpretation only.
> The best way to describe what you are asking..say a slow roll to the
> left is to first understand that a slow roll isn't exactly a roll dead
> on the longitudinal axis as the axis relates to a "level" roll. The
> visualization of a slow roll to the left can be made by envisioning a
> reverse capital letter D, which naturally isn't in my little bag of
> computer symbols, so a roll to the right is much easier to visualize.
> So to the right, you can envision a capital letter D.
> The reason for the D shape is because to do the roll properly, you
> will have to pass through exact inverted at the airplane's level
> flight inverted attitude to keep altitude in check during the roll.
> The tightness of the D shape will depend on the wing design of the
> airplane you're flying. A symmetrical wing on a Pitts, or an Extra for
> example will be a much tighter D than say a Citabria with a high lift
> cambered wing.
> Anyway, the vertical line of the D represents the raising of the nose
> during the first half of the roll until right past the full inverted
> position. At that point, the nose must again be lowered to a normal
> level flight attitude, and this is represented by the curve on the D
> returning the airplane back to upright level flight attitude.
> The roll can be done with inside rudder at roll initiation or without
> inside rudder. When flying airshow demonstrations, I seldom used
> inside rudder with inside aileron when initiating a slow roll. Reason
> for this is that adverse yaw will pull the nose outside, which if
> caught exactly right, will result in your going straight to the
> required top rudder you need to carry you through knife edge at the
> right spot on the roll axis, and if it's a point roll, you don't have
> to change feet at the first point, but to do this requires a fairly
> fast roll rate, so it's aircraft specific. In the P51 for example, the
> roll rate isn't fast enough to use the adverse yaw generated so that
> it negates the normal inside rudder you need to counter that adverse
> yaw, which in turn means you enter with aileron and inside rudder, and
> immediately go to top rudder as soon as a positive coordinated roll
> entry has been accomplished.
> Back to the Pitts, entering into the first knife edge, you have steady
> inside aileron and have blended in enough positive pitch with elevator
> to climb the vertical D line nose high for the inverted level
> transition.You hold top rudder through knife edge and then start
> blending in whatever forward stick you need to pin the nose at level
> inverted. You're also blending off the top rudder at this point at a
> rate that will neutralize it passing through inverted. Stick at this
> point is forward and in the corner for aileron and elevator blending.
> Passing through inverted, you switch to opposite side top rudder and
> reverse the procedure, blending in past the second knife edge, as you
> come back down the backside of the D curve whatever back pressure you
> need to return the nose to normal level flight attitude.
> What I've just described is much better learned in actual flight,
> where a slow roll can be done by rote, then understood
> afterwards...........and in far less words to boot :-)
> Dudley Henriques
> International Fighter Pilots Fellowship
> for email; take out the trash
>
>

[Dudley Henriques]

"Maule Driver" > wrote in message
om...
> We are on the same page. The analogy with describing lift is spot on.
>
> Never flown a 195 but I bet it rolls a bit with rudder too. I'd bet
> it has
> a little to do with fuselage blanking the trailing wing lift a bit
> while
> the leading wing works a little better. But all of that is a wild ass
> guess. I'll have to ask our resident 195 guy how it responds to
> rudder.

I flew one years ago. Strong airplane...reminded me of something made
out of solid aluminum :-)) It flew wonderfully...extremely stable. Sort
of like a Beaver really.
As for a turn resulting from pure rudder input on these airplanes....you
still have that outside wing going faster than the inside wing
irregardless of the existence or non existence of dihedral, so it will
turn anyway eventually :-)
Dudley

[soxinbox]

I don't think anyone has hit on what is really going on here. The
explanations about the sideways force created by lift when the AC is banked
cause it to move ( accelerate ) to the side, but not rotate. The dihedral
wing explanation doesn't work either, because the raised wing's horizontal
force is applied aft of the CG, thus causing rotation in the opposite
direction of the turn. The major reason that a plane rotates about the
vertical axis during a turn is wind vaning.

You bank the plane, the lift is broken into horizontal and vertical
components. The horizontal force causes the plane to accelerate to the
side, but not rotate as others have stated. Now with the plane picking up
speed in the lateral direction, the relative wind is now coming from one
side of the plane, a forward quartering headwind! As anyone who has taxied
on a windy day knows, planes have a natural tendency to face into the wind.
This is caused by the big wind vane we call a tail. This rotates the plane
into the wind. The relative wind is thus always leading the plane by a few
degrees, causing a continued rotation. And as a side benefit, the
horizontal acceleration is countered by the centripetal force of the turn,
so we don't continue to accelerate to faster and faster horizontal speeds.

[Hilton]

Andrew,

Andrew Sarangan wrote:
> Hilton wrote:
>
> > Andrew Sarangan wrote:
> >
> >> Sure, but that still does not explain why the airplane turns. A
> >> horizontal component of lift will make the airplane side-slip, not
> >> turn. It is the stability (weathervane effect) that makes the
> >> airplane turn.
> >
> > By definition, the 'weathervane effect' occurs because air exerts more
> > pressure on one side of the object (aircraft) than the other - same
> > definition as slipping. Therefore, are you are asserting that an
> > aircraft turns because it is slipping? More over, it will only turn
> > if it is slipping?
> >
> > Hilton
> >
>
> Think of the space shuttle. If you fire rockets horizontal to the flight
> path, the shuttle will slide sideways. It will not turn the nose towards
> the direction of travel. An airplane turns because it wants to point the
> nose into the relative wind.

I understand that, but you never answered my question: "Are you asserting
that an aircraft turns because it is slipping (weathervaning)?"

Hilton

[Corky Scott]

On 6 Nov 2004 07:37:15 -0800, (Ramapriya) wrote:

>Hi guys,
>
>Unlike the elevators and rudder that change an aircraft's pitch and
>yaw with no other secondary effect, why does the banking of wings by
>the use of ailerons not just roll an aircraft but also produces a turn
>(yaw)?

Very basically, because the wings are producing lift. They continue
to produce lift no matter what angle the airplane banks to. When the
wings are banked, the lift pushes sideways now, not straight down
anymore. So the airplane now lifts around in a curve.

> Logically, one would expect an aircraft to keep going straight
>ahead even if the pilot banked the aircraft left or right. Where does
>the turning effect come from?

Lift. Bank the airplane sideways and the lifts around in the
direction of the bank.

>Is there a website you know of that can teach me such basics, without
>having to bug you? :)

Corky Scott

[Mike Rhodes]

On Sat, 06 Nov 2004 22:22:22 GMT, Mike Rhodes
> wrote:

>
>A banked aircraft will not turn if, and only if, the wing is not
>generating lift. A wing will not generate lift if its angle of attack
>is so controlled by the horizontal stabilizer.

I was not quite right with the "if and only if". Of course the rudder
can also stop the turn, as in a side-slip. And the side-slip Peter
mentioned is what pushes the nose around in the turn by its push on
vertical stabilizer. I did not point directly at the vert stabilizer
as Peter did in his reply.

Because the banked aircraft is aligned less with gravity, it would
then want to accelerate 'up', as 'up' is relative to the aircraft.
But this would immediately change the angle-of-attack of the both the
wing and the horizontal stab. So the wing loses some lift, while the
horizontal stab increases its already downward push. This would tend
to push the nose 'up', and restore the angle of attack of the wing.

The turn is a relatively slow process (the pilot has time to make
adjustments), and maybe the mechanics are not so simple as I think my
post implied.

--Mike

[Mike Rhodes]

On Mon, 08 Nov 2004 19:30:24 GMT, Mike Rhodes
> wrote:

>On Sat, 06 Nov 2004 22:22:22 GMT, Mike Rhodes
> wrote:
>


>Because the banked aircraft is aligned less with gravity, it would
>then want to accelerate 'up', as 'up' is relative to the aircraft.
>But this would immediately change the angle-of-attack of the both the
>wing and the horizontal stab. So the wing loses some lift, while the
>horizontal stab increases its already downward push. This would tend
>to push the nose 'up', and restore the angle of attack of the wing.
>

Oops. I got this wrong. If both wing and horizontal stab are pushed
down then the net effect is no change in angle of attack.

--Mike

[Ron McKinnon]

Ramapriya wrote:
> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect,

None of the controls really operate without producing secondary
effects. Rudder-only will produce Yaw, of course, but the yaw
accelerates one wing forward and one wing back, which changes
the airflow over the wings - the forward-accelerating wing
produces additional lift, the aft-accellerating wing less,
producing a roll. Its a sloppy turn, but it can be done.

Elevator changes the pitch, which typically will affect the
angle of attack and thus the lift produced by the wings, and
may produce a climb or descent which will affect the airspeed, ...

>why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?

The wings produce Lift. In straight and level flight, the lift
vector is straight up. When you bank, you change the direction of the
lift vector - the bank introduces a lateral component that accelerates
the aircraft in that direction - the turn. The rudder is used in
this case only to counteract any adverse yaw produced by the ailerons in
commanding the bank. And the 'tail feathers' (vertical stabilizer) tend
to keep the aircraft aligned with the airflow.

> Is there a website you know of that can teach me such basics, without
> having to bug you? :)

There are many. But try: http://www.av8n.com/how/

[Andrew Sarangan]

Yes, my understanding is that a bank causes an airplane to slip, which
then causes it to weathervane into the wind. Why do you ask? Is there
something I am missing?



"Hilton" > wrote in news:lUGjd.8614$O11.3080
@newsread3.news.pas.earthlink.net:

> Andrew,
>
> Andrew Sarangan wrote:
>> Hilton wrote:
>>
>> > Andrew Sarangan wrote:
>> >
>> >> Sure, but that still does not explain why the airplane turns. A
>> >> horizontal component of lift will make the airplane side-slip, not
>> >> turn. It is the stability (weathervane effect) that makes the
>> >> airplane turn.
>> >
>> > By definition, the 'weathervane effect' occurs because air exerts
more
>> > pressure on one side of the object (aircraft) than the other - same
>> > definition as slipping. Therefore, are you are asserting that an
>> > aircraft turns because it is slipping? More over, it will only
turn
>> > if it is slipping?
>> >
>> > Hilton
>> >
>>
>> Think of the space shuttle. If you fire rockets horizontal to the
flight
>> path, the shuttle will slide sideways. It will not turn the nose
towards
>> the direction of travel. An airplane turns because it wants to point
the
>> nose into the relative wind.
>
> I understand that, but you never answered my question: "Are you
asserting
> that an aircraft turns because it is slipping (weathervaning)?"
>
> Hilton
>
>
>





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[Andrew Sarangan]

That is exatly what I said in a previous post on this thread. A bank causes
an airplane to side-slip, which in turn makes it point into the wind.



soxinbox > wrote in
. 165:

> I don't think anyone has hit on what is really going on here. The
> explanations about the sideways force created by lift when the AC is
> banked cause it to move ( accelerate ) to the side, but not rotate.
> The dihedral wing explanation doesn't work either, because the raised
> wing's horizontal force is applied aft of the CG, thus causing
> rotation in the opposite direction of the turn. The major reason that
> a plane rotates about the vertical axis during a turn is wind vaning.
>
> You bank the plane, the lift is broken into horizontal and vertical
> components. The horizontal force causes the plane to accelerate to the
> side, but not rotate as others have stated. Now with the plane picking
> up speed in the lateral direction, the relative wind is now coming
> from one side of the plane, a forward quartering headwind! As anyone
> who has taxied on a windy day knows, planes have a natural tendency to
> face into the wind. This is caused by the big wind vane we call a
> tail. This rotates the plane into the wind. The relative wind is thus
> always leading the plane by a few degrees, causing a continued
> rotation. And as a side benefit, the horizontal acceleration is
> countered by the centripetal force of the turn, so we don't continue
> to accelerate to faster and faster horizontal speeds.


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[Malcolm Teas]

(Ramapriya) wrote in message >...
> Hi guys,
>
> Unlike the elevators and rudder that change an aircraft's pitch and
> yaw with no other secondary effect, why does the banking of wings by
> the use of ailerons not just roll an aircraft but also produces a turn
> (yaw)? Logically, one would expect an aircraft to keep going straight
> ahead even if the pilot banked the aircraft left or right. Where does
> the turning effect come from?

Think about the direction of lift from the wings. When the ailerons
roll the plane, the direction of lift points partly sideways. That
will pull the plane to the side. It's not quite that simple, but
that's the nut of the matter.

> Is there a website you know of that can teach me such basics, without
> having to bug you? :)

Well, a newsgroup is for posting questions. But, you might want to
check out: <a href="http://www.av8n.com/how/">See How It Flies</a> as
well.

-Malcolm Teas