Thinking through this further and again, one would have to have this
planned out in advance...Â* At the top of the loop, the airspeed will be
considerably lower than at the bottom.Â* So, at the top, one could
perform a half roll (an Immelmann turn), and, since the glider would now
be upright at lower airspeed, it would begin a climb but would stall
near or before reaching vertical.Â* This would result in near zero G and
would be an ideal time to bail out.Â* It might even result in negative G
which would make all the easier.

The half roll could even be done past the top of the loop (half Cuban
Eight).Â* Again, the glider would start to climb but would not have the
energy yet to complete a loop, making bail out rather easy.Â* BUT...Â*
being unprepared for the first high G maneuver, the pilot(s) could
simply be unconsious...

I hope I never get the chance to prove this right or wrong.

On 9/28/2018 9:16 AM, Tango Whisky wrote:
Le vendredi 28 septembre 2018 15:15:05 UTC+2, Michael Opitz a écritÂ*:
What am I missing here? Why can't the glider be maneuvered into
something like a constant 80 degree bank turn? Then pull out the
dive brakes to slow it down and reduce G available? As the speed
bleeds off, reduce bank angle to let the nose float up and slow down
more. Then, jump out before the thing stalls and starts spinning.
Get the vertical gravity vector out of the picture so that the speeds
don't accelerate like they might on the back side of a loop. 10 G's?
For how long? I pulled 9+ G's on many occasions in the F-16, and to
sustain it for any length of time required full afterburner which a
DUO doesn't have.
RO
Michael, you are probably right that on the top of the loop, you may try to use aileron and rudder to shift the loop into an high-bank turn. This turn would still have a high g-load, and opening the airbrakes at 80 deg bank would still put the wings beyond ultimate stress load (which is 40% lower than with airbrakes closed).
But then - you'd have to perform this manoeuver a second after you have blacked out at the lower part of the loop. During my early aerobatic training I once blacked out (with the instructor in the back seat) 45 deg nose up because I had relaxed my respiration to early, and it took me a couple of seconds to come around and understand what's happening - during this time, the glider had proceeded through the loop to 20 deg nose down (and it wasn't intended to be a loop).
So if the description of the eye whitnesses is correct, I think that the situation was not survivable, and I join Uli in his wish that by then, the crew was out of it.

Still frightening that such a situation might develop out of the blue.

Bert TW


--
Dan, 5J