The desired effect is to have the airfoil stall before breaking but at the
same time that the pilot not lose control. Gusts may increase indicated
airspeeds and consequently produce more stress on the airplane, so from this
standpoint slower is always better. On the issue of controlablity, faster
is better. Vb is the speed that is supposed to provide the best compromise.
There was an article in Business and Commercial Aviation a few years ago
that had a comprehensive explanation but I no longer have the issue. I seem
to recall that for swept wing jets Vb is greater than Va and may even be
greater than normal cruise. Of course jets are also concerned with mach
exceedances and upsets so the issue is more complicated for them

Mike
MU-2

"Doug" wrote in message
om...
Kershner's "The Advanced Pilot's Flight Manual" has the following
definition for Va.

Va - The maneuvering speed. This is the maxiumum speed at a particular
weight at which the controls may be fully deflected without
overstressing the airplane.

Note that this definition DOES NOT say that the airplane will stall
before it breaks due to turbulence.

Now, Va is commonly taught as turbulent air penetration speed. But
nowhere in the definition does it say that Va will protect the
airframe from damage due to turbulence.

Does slowing down even slower than Va protect the airframe from even
more severe turbulence? Or is Va the best speed for turbulence
penetration? Or is Va just used as a turbulence air penetration speed
becauase of tradition or some other non-technically correct reason.