At 01:37 AM 24/09/04 +1000, you wrote:
>At 10:23 AM 23/09/2004 +1000, Mike Borgelt asked:
>>do we have anyone here who knows what is done in Germany
>>and the US?
>
>Perhaps their theoretical treatment of spin entry, spins and recovery, and
>limitation of practical experience to slow flight and stalls, explains the
>relatively poor record of US pilots in situations where they encounter a
>real (deliberate of accidental) spin, compared to the rest of the world
>with the emphasis on recognition and recovery from the developing stages of
>a spin.
Thanks for the post of the US requirements.
So is there any evidence for your assertion?
That is what I was aiming to find out as I thought the US did not require
full spin training in gliders.
As the Avweb article pointed out a few weeks ago we had a perfect case with
Canada and the US for the worth of compulsory spin training with power
planes with a 50 year sample and there was no good effect.
Somewhere there should be some stats that can test this for gliders now.
Then we're doing science.
>
>And for those who were wondering, the certification requirements for the
>most commonly used worldwide airworthiness standard, JAR 22, require
>demonstration of recovery from a fully developed spin, at the most adverse
>weight and centre-of-gravity condition, and if the glider is able to carry
>water ballast, with the tank on one side full and on the other side empty -
>with recovery commencing within 1 turn of the initiation of control input
>using the technique listed in the aircraft's flight manual.
>
>Hence the importance to RTFM - in this case - read the FLIGHT manual (and
>not exceed CG limits etc and adopt the recommended technique).
>
>There was discussion some 12 - 18 months ago regarding the possibility for
>the Puchacz to occasionally adopt a flatter mode of spinning at rearwards
>CG. This mode involved a flatter attitude and slower rate of descent, but
>also a delayed recovery (i.e. it took more than 1 full turn after the
>initiation of recovery before the recovery took effect) if the aircraft was
>held in a developed spin beyond the stage of established autorotation.
>
>In other words - while recovery still happens, it takes longer to begin if
>the spinning certification requirements are exceeded.
>
>My own club has adopted the practice of avoiding rearward CG positions
>approaching the limit, by use of the ballast bars provided with the
>aircraft - particularly if intentional spinning is contemplated.
So what does JAR 22 require for number of turns maximum to be demonstrated
before recovery action is initiated?
This may be of interest to those who spin to descend quickly.
If you are at high altitude in wave be aware that the inertial forces/aero
damping will be higher and this may have interesting consequences.
Be aware of the effect of in and out spin aileron.(Best demonstrated in a
Pitts) The test pilot did it right. You may not.
We lost a Blanik and two people in spin training a few years ago after the
spin turned in to a spiral. Two Nimbus 4DM's have broken up in flight after
upsets with experienced pilots on board(3 dead out of 4 - 1 jumped)
I didn't spin the CT4B last Monday because I read the handing notes.
Standard spin recovery is meant to work after 1 1/2 turns. Fair enough.
Then it says "if recovery does not occur within 4 turns consider leaving
the aircraft".
This doesn't seem nearly predictable enough to me(and is a great argument
for wearing parachutes and being high enough to use them) and I definitely
won't spin the Puch. Those who insist on it may find themselves in a very
interesting legal position if one spins in here during spin training, given
the history.
There are definite hazards to spinning and the recovery with modern gliders
has a good chance of going outside the envelope if you are a little slow in
your actions and let it get beyond the very first stages of the incipient.
Flapped gliders usually have a quite low max positive flap speed which is
very easily exceeded. Let a spin develop accidently from a thermalling turn
and you likely are in positive flap. Somewhere before the recovery you
really ought to go to negative flap. I wonder if this gets tested during
certification?
Mike
Borgelt Instruments - manufacturers of quality soaring instruments
phone Int'l + 61 746 355784
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