Re: alula

["James R. Cunningham" <jrccea@bellsouth.net>]

Garrison L. Hilliard wrote:

>   Insofar
> >as I know, none of them has a device of this nature installed.
>
> Think "flaps", Jim.

Hi Garrison,Thanks for the tip.  Flaps didn't occur to me because they have a
different function.  Alulas don't work like flaps, nor do they generally
serve the same purpose. To oversimplify a bit, a flap shifts the entire lift
curve.  An alula extends the unshifted curve before it peaks.  The first
three of the planes I mentioned don't have flaps. Most light planes that do
have flaps use them primarily to add drag rather than lift, to decrease the
L/D ratio and steepen the glide angle when the final approach to landing is
too high.  In planes without flaps, the flap drag function is approximated by
cross controlling the ailerons and rudder, in a process call slipping.  I
expect you know this, but some of the guys may not, and I mention it for
their benefit.

Jim