At 12:00 PM 24/02/06, you wrote:
Mike
Many thanks for starting this thread.
Mike Borgelt <[EMAIL PROTECTED]> wrote:
> Interesting article on stalls and avoiding stalling in the latest
> "Australian Flying". Basically don't pull the stick back too far!
>
> Seems stick position awareness might be the key to in
> training to avoid unintended stalling.
This issue becomes a problem while low.
-Training tells pilots to maintain safe airspeed near the ground however
a couple of factors work against this.
PANIC
As the ground comes up closer the natural reaction of some people is to
want to pull the stick back to get away from the thing that could hurt
them THE GROUND.
DOWNWIND RUSH
The closer you are to the ground the faster you seem to be going which
means there is a tendency on some pilots in a low downwind leg to want
to pull the stick back to slow up.
I think you are missing the point. Aviation has been training pilots
to maintain a safe airspeed for the last 100 years and we still have
accidents that involve inadvertent loss of control through stalling
and its consequences. We've had training in full spin recovery,
incipient spin recovery, full stall and recovery training, "approach
to stall" training, maintain safe speed near the ground etc and STILL
pilots inadvertently stall.
"Maintain safe speed near the ground" is a workaround to avoid
teaching full and correct understanding. One glider repairer said to
me recently it was his opinion that it was resulting in lots of
damage to gliders as people scoot across the airfield trying to force
the thing on the ground. It won't do much good in outlandings either.
>
> A couple of thoughts:
>
> Maybe there should be a display of stick position in the pilot's
> field of view?
>
> Maybe a strong compression spring could be arranged so that at the
> stick position for minimum sink pulling the stick further back
> requires noticeable extra effort. The position will depend on the C
> of G position but this could be dialled in after doing that calculation.
The trim lever does this function however the pilots adjusts it as he
sees fit !!!!!!
No, the trim lever simply biases the stick forces and the stick force
vs stick position relationship is still basically linear. I'm talking
about a non linear force that occurs when you pull the stick
back.beyond a certain position. It would still let you go to the hard
stop when required (deliberate spins, avoidance of terrain or other
aircraft requiring Max lift coefficient but for normal soaring you
don't need much more lift coefficient than that required for minimum
sinking speed. For a glider whose maximum lift coefficient is 1.6 and
which stalls at say 38 knots and has min sink at 43 knots the lift
coefficient at 43 knots is only 1.25. A long way to go to the stall
in both lift coefficient and angle of attack.
Wheels up warning alarms are common, however our safety could be much
more enhanced if we had some kind of 'Stick too far back warning' once
we are at circuit height.
Given that we don't want people stalling in thermals and endangering
those below we might want the warning all the time.
The problem is that we fly by stick force most of the time and it is
only near the stall that stick position really matters.
Anyway, read the article. It is made quite clear that fore and aft
stick position is all there is to it.
Everyone can go and verify this this weekend by going flying and
carrying out the exercises mentioned.
Lets hear from those who do this, this weekend.
Mike
Borgelt Instruments - manufacturers of quality soaring instruments
phone Int'l + 61 746 355784
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email: [EMAIL PROTECTED]
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