A very basic question

"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/

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

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.

"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.

" 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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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

"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.

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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. (

Marty

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

"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