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Old June 30th 05, 08:20 PM
Chris Reed
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And I should add that I was explaining the exercise from memory and may
have got the speeds wrong. 90 kts is definitely over the top for
starting - pull up from 65 or 70 into a 45 degree climb so as not to
throw more height away at the outset.

In the case of a real cable break, climbing at 45 at 60 kt you *will*
take a second or two before you begin the pushover (and if you have
quick reactions pretend to be an out of practice, early solo pilot).
Then it will take the aircraft another second or two to complete the
pushover, which will mean the speed decays further. Performing this
exercise, I'd expect to see the normal gliding attitude with a speed of
perhaps 30kt or even as low as 20kt, but you're still flying because of
reduced G. Mike is quite right that the controls don't feel quite right,
but you're concerned to make the turn as early as possible because
you're just at that awkward height where you can't get in ahead but are
low for an abbreviated circuit (say 450ft at my airfield) so you turn,
the G comes back on, and the wing drops.

Whether you enter a spin will depend on the aircraft - our K21 won't
spin, even in this exercise, so falls out into a spiral dive. The
Puchacz rolls smoothly into the spin without any buffeting or other
warning, and I suspect most Polish gliders would do the same. Our K13
used to do the same, though in a more stately fashion, but since
re-covering seems more reluctant.

My point was not that a spin is inevitable, but that many gliders will
spin from this even though you are flying co-ordinated.

jonnyboy wrote:
Mike Schumann wrote:

It is not obvious to me, why, in a cable break scenario, you would be close
to stalling when you push the nose down to a normal attitude while you
maintain 60 knot airspeed. This sounds like you are flying significantly
above stall speed. Could you elaborate?

Thanks,
Mike Schumann



Mike;
I don't think Chris means he maintain 60 knots.
Starts at 60 knots, but with the nose up speed decays.....
Push the nose over to an *attitude* that in normal flight would give
around 60 knots and the trap is set....

Real speed is ~ Vs (say 40k) but attitude is good and she IS flying
(as G 1)

once the G reverts to 1 you either have a good angle of attack/speed
and you are flying
or you don't and you arent.

thats my take - Vs increases in a tight turn as g1.
so... when G1 (bunt/top of loop etc.) Vs *reduces*


;-) Jonny.