Light-Sport Aircraft Yahoo group Re: Why does it TURN (not just slide sidewards) when you bank w/ no rudder?

In level flight the lift vector is straight off the top of the vertical stab. When you initiate a bank with ailerons only, say to 30°, your lift vector remains straight off the top of the vertical stab, but due to lift angle it is now pulling you off to one side, think of swinging the plane on a string. Once the desired angle of bank is achieved the ailerons are centered and the angle of bank will remain fairly constant. If no elevator input is added the turn will continue, but altitude will be lost. The wings are now also traveling at different speeds. Think of playing crack the whip. The inboard wing tip will reduce in speed, which will reduce the lift which reduces the induced drag. The outboard panel will accelerate and increase lift, increasing induced drag. This will cause the aircraft to yaw to the outside of the turn unless rudder is applied to counter the adverse yaw. Some aircraft have interconnects between the ailerons and rudder making rudder inputs by the pilot less critical or unnecessary (think Ercoup). Some A/C are quiet intolerant of lazy feet, think Champ or Cub. If you don't lead the turn with a bit of rudder you'll be in an uncoordinated turn and find yourself sliding all over the seat. Dihedral has little to do with the turning aspect of an aircraft and more to do with it's stability in straight and level flight. Look at the dihedral on a low wing such as a Piper Warrior, or Beach Bonanza, You'll notice it's quiet pronounced. Compare it to a Cessna which has very little. The pendulum effect of the high wing negates much of the need for dihedral to maintain stability.

--- In Sport_Aircraft@yahoogroups.com, "circicirci" <acensor@...> wrote:
>
> Hey Bill,
>
> Thanks for that question. I'd been thinking about that.
>
> To recap your question (which is below):
> In level flight without any rudder you bank. The plane turns to the side of the bank. The horizontal component of lift should slide the plane sidewards towards the side you have banked but continue to fly straight ahead but banked. It does not explain what makes the plane turn on a circular course.
> So what's making the plane TURN?
>
> Gary, I don't see how dihedral explains the plane _turning_ toward the side of the bank. All postive dihedral does is create a tendency for the plane to return to level flight if you let go of the controls.
> Negative creates a tendency for the plane to continue to roll further once you start a bank.
>
> Somehow the bank must be creating more drag on the lower wing (or less on the raised wing) creating the turning force.
>
> My guess is the raised aileron on the lower wing -- being in the different airflow of the upper wing surface -- creates MORE drag on the lower wing than the lowered aileron on the raised wing does.
>
>
> Alex
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