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Old May 11th 09, 06:31 PM posted to rec.aviation.soaring
Chris Reed[_2_]
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Posts: 56
Default Spin recovery vs tail design

Ron Ogden wrote:
I would like to solicit comments on the question: Compared to a standard
tail configuration such as a 2-33 or Blanik L-13, does the initiation and
recovery from a spin vary substantially in T-tail (ASK-21 type),
all-flying (Phoebus) or V-tail (HP series) sailplanes? Really look forward
to reading and learning.


The main difference, to the extent that there is any generic difference,
might be that T-tails tend to end up rather more nose down after you've
stopped the spin. However, this may not be true for a particular model
of glider. Also, your timing of the spin recovery will alter this, and
other matters.

Of those I've spun:

K13 (low tail) - quite gentle, recovers into a dive but not a
particularly steep one.

K6cr (low tail) - ditto, though it all happen quicker than a K13.

Puchacz (mid tail) - recovery may be into a dive beyond the vertical and
substantial height loss per turn, but it does exactly what the manuals
say if you perform the recovery properly.

Astir CS (Grob 103, T-tail) - quite gentle, recovers into a steeper dive
than the K13

IS28 (T-tail) - like the Astir, but a bit slower all round.

Open Cirrus (mid tail) - fairly gentle, dive after recovery about as
steep as the Astir. However, you do need FULL rudder to stop the spin
(and the last inch requires a hard push; it feels like you're on the
stop but you're not).

I've read that some V-tails need full forward stick before they recover,
but haven't had the pleasure of flying any.

Of my list I'd say the most "extreme" attitudes on recovery are from the
Puchacz, so from my limited experience the difference in tail
configuration is not the most important factor.