ASW 20 SPIN CHARACTERISTICS

On 15 Jul 2004 06:43:05 -0700, (Andy Durbin)
wrote:

(Chris OCallaghan) wrote in message . com...
In fact, if you think about it, there would be a change in AoA as the
wings returned to their normal 1g state. The AoA increase at the tips
would be greatest and negligible at the roots. How large an increase
are we talking about? Pretty darn small. An amusing exercise though. A
friend once figured out how thick a layer of material a tire leaves on
the road, given normal wear. This seems on the same order.


According to Thomas, Fundamentals of Sailplane Design, the wing twist
of the ASW-20 is 2.5 deg (page 210). Isn't twist designed into a wing
to prevent the tip stalling before the root? If my numbers were
derived for 68 knots instead of 40kts they give a result that is
similar to the designed-in wing twist. In other words, the wing flex
effect appears to completely offset the protection provided by the
wing twist.

If the pilot is pushing over hard the wing will be carrying a reduced
load. As a result the stalling speed will be reduced: remember that a
stall occurs when the wing fails to generate the lift needed to
support the current load on the wing and is only indirectly connected
with the AOA and Cl figures. In the case we're considering the stall
speed will be reduced below normal because the push-over is creating a
reduced G situation.

I haven't noticed you mention this factor. How does its inclusion
affect your calculation?

--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :