A very basic question

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.

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





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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

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.

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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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

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/

(Ramapriya) wrote in message . 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?

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