"Doug" wrote in message
om...
Orval Fairbairn wrote in message
.. .

Va is the MAXIMUM speed (at max gross weight) at which the aircraft can
be stalled without exceeding its max designed load factor. The lower
the gross weight, the lower the effective Va (due to engine mounts,
etc.)

Where does the above definition come from?

You'll not find it anywhere, because it is incorrect.

You'll find Va covered in the FAR's for part 23 certified
aircraft he-

http://www.access.gpo.gov/nara/cfr/c...4cfr23_00.html

The relevant sections are 23.335 (where you see that Va
can be *no less than* Vs*sqrt (load factor) -- which means
that _it can be greater than this_, and 23.423 where its
relationship to control surfaces is discussed.

Short answer: Va is defined in terms of what the *control
surfaces* can handle, not what the plane can handle.
However, Va must be sufficiently high to satisfy 23.335,
which means (oddly) that there is no regulatory requirement
that stops you from flying at Va without exceeding the load
factor. Well fancy that!.

--
Dr. Tony Cox
Citrus Controls Inc.
e-mail:
http://CitrusControls.com/