kinsell wrote on 1/8/2021 10:26 PM:
On 1/8/21 5:53 PM, Nicholas Kennedy wrote:
The problem with the initial model of the ASw 20 spinning inadvertently was caused by poor
pilot training coupled with this idea that having the CG way aft was the way to go.
Pilots would put down the 55 degree flaps and forget or just not, trim for a pattern speed
hands off.
The flaps are large, and if you put them full down and forget to trim and get distracted and
let go of the forward pitch pressure the plane will rapidly slow down and stall.* Coupled
with low altitude and a full aft CG this situation was a recipe for disaster. And yes, there
were several accidents.
When I got my ASw 20 check out this issue was beat into me by a couple of sharp cookies.
I never had a problem.
The fully rear CG thing is interesting, working with Tom Brenza in MoriarityNM I started out
at about 50% aft for about 60 hours. Then I went to about 85% aft. Then, I thought anyway,
doing alot of high speed cruising at 17+ out west my plane climbed great and ran best at
about 60% aft CG.
Every thing I have owned easily spins, Except our* ASK 21- My Blanik L-13 was a great ship to
do as many spins as you wanted in both directions. My Ka6 CR was really good at controllable
multiple, long duration spins, as is my LS3a.
I spent a Fall living in Fort Collins Co and got checked out in their C-150.
I would come over CX house high and spin that thing like crazy, musta done 200+ in that thing
and got really comfortable doing them.
Nick
T


Found an article that claims the '20 spins like a top with landing gear down and landing flaps
selected, but is stable otherwise:

http://flsc.org/portals/12/PDF/Spinning.pdf

I'm surprised to hear that it will spin readily with the full landing flap, because that also
puts the ailerons into negative deflection. That makes it very difficult to stall the tips, a
usual condition for spinning. Perhaps the full deflection affects the airflow over the tail,
and that is cause?

The reason I heard the reason for changing from 60 degree deflection to 40 degrees was to avoid
damage to the flap rods in a hard landing, which was often undetected until the next landing.
Selecting full deflection would then fully deflect only one flap, giving a strong rolling
motion and a very surprised pilot.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1