Snap roll vs. Va

Most things in aviation are related to the wings-level, 1-g stall
speed, Vso. The maneuvering speed, Va, is actually the stall speed of
the airplane at the design limit, and it is related to Vso by the
square root of the g-load. (Of course, all of these are CAS, so you
may have to do some massaging through the airseed calibration data to
convert back and forth between IAS and CAS to find the numbers you
must read on the airspeed indicator.)

For example, in aerobatic airplanes like the Citabria which were
certificated at +5.0 g's (at max. gross), Va = 2.24 x Vso. In
aerobatic airplanes certificated at +6.0 g's (at max. gross), Va =
2.45 x Vso.

In terms of the snap roll entry speed (and snap rolls are really
accelerated stall/spins), the speed will naturally fall somewhere
between Vso and either 2.24 or 2.45 x Vso.

In Eric Muller's book, Flight Unlimited, he recommends intially
practicing snap rolls at 1.5 x Vso, so there's a starting point. In my
experience, I'd recommend around 1.6 x Vso as a good "recommended"
snap roll speed, which translates into a 2.5-g pull to stall/spin the
airplane at that speed. The MAXIMUM snap roll speed should probably be
no greater than about 1.7 to 1.8 x Vso...

Hope this helps (and HI Ken!),

Rich
http://www.richstowell.com




"Ken Ibold" wrote in message . com...
In a 7GCAA, Va at max gross is 120 mph and the recommended snap roll entry
speed is 85 mph.

"Greg Esres" wrote in message
...
For those of you who have aerobatic airplanes, I'd be interested in
data about the recommended entry speed for a snap roll vs. what Va is
in your airplane.

Thanks for any info.