Glider accident while filming commercial in 2011. NTSB Report updated
Hi Nigel,
On Mon, 01 Jul 2013 14:58:00 +0000, Nigel Pocock
wrote:
If Bill D could be bothered to read my posting before spouting a reply he
wouls see that I had started the launch with full forward stick in both
cases.
Really bad mistake. Will make you want to change your pants after you
trtied this in a glider with full-flying elevator. NO glider will take
off with the stick full nose-down if the CG is halfways right.
Hard acceration with these gliders can cause the tail to hit the ground
hard - not safe.
Safe. Happens all the time, this is what the glider is designed for.
To avoid this the tail of the K8s are usually held down
for the launch. Too hard acceration can cause the glider to shoot into the
air and immediately into a 45 degree climb despite the stick position.
Absolutely not.
If
the rope breaks at this point you have too little height to recover. Hence
the winch driver will give slower initial acceleration with these types.
By regained control I mean the elevator having any effect. Until then you
are just a passenger.
Absolutely not.
Really sorry to contradict, but the dangers you are describing are
simply not true (or, rather, caused by bad training).
Even if the tail hits the ground more or less hard (which is easy to
avoid by applying power smoothly), the glider takes off at a speed
where elevator control is always perfectly sufficient to control the
pitch up momentum. If the wing flies fast enough to lift the glider,
the elevator flies fast enough to prevent pitch up - if the elevator
is kept in the correct position.
In case you did not know this: Elevator size of at least any German
designed glider is certified (and verified) that there is always 100%
elevator authority to prevent pitch up.
If the acceleration pushes back the hand that is holding the stick
(or, by using a soft cushion, the whole pilot moves backwards), things
look differerent...
In my club we've been doing winch launches for the last 60 years now,
with about 200.000 winch launches. ***Not one single accident*** due
to the causes you describe. Hundreds of pilots,hundreds of student
pilots, hundreds of winch drivers, dozens of instructors, half a dozen
of different winches from an 120 hp V8 engines to 280 hp turbo
Diesel. Gliders range from Spatz, Ka-6, Ka-8, to ASH-25.
Not one single accident.
And no, we do not push the tails of our Ka-8s down.
I've seen morre winch launches that I care to count where the gound
run was less than 6 ft. (ft - not yards!). Naught to 40 mph in less
than a second.
*Any* too-steep winch launch that I ever saw during the last 30 years
was caused by nose-up elevator at the moment of lift off. Any.
I was always taught with ground launch to keep it straight and level until
the glider lifts off in a shallow climb. When a safe speed had been reached
to rotate steadily into a full climb. At any point in this process you can
still recover and land safely using the correct procedures - as taught be
both the german and british systems.
The German system teaches to keep the stick in the recommended
(trimmed) position. If done halfways properly, any glider will launch
itself and rotate into the climb smoothly ***without any elevator
input***.
Works like a charm for absolutely any glider, be it an L--Spatz, a
Ka-8 or a heavy ASH-25.
An absolute no-no is launching with full nose-down elevator as you are
doing it. Makes a smooth transition into the climb really hard and
often leads to over-controlling.
Cheers from Germany
Andreas
p.s.
The only case where the elevator is not able to control a nose-up
rotation of the glider is, if a full-flying elevator is pushed fully
forward, therefore stalling the complete horizontal tail.
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