On Monday, February 1, 2016 at 4:30:20 PM UTC-5, Don Johnstone wrote:
At 20:13 01 February 2016, Tango Whisky wrote:
Le lundi 1 f=E9vrier 2016 20:01:27 UTC+1, Don Johnstone a
=E9crit=A0:
At 18:23 01 February 2016, Ramy wrote:
Scary! And I don't think there are that many nimbus 4DM out
there.=20
Will be
interesting to compare this number to number of 4DM made.
I=20
wouldn't want
to fly one myself.=20

Ramy=20
=20
It would appear that 100 Nimbus 4D were built, of those 11
were 4DT=20
and 12 were 4D leaving a total of 87 DM of all types.
=20
There is a list of 7 accidents in the previous post due to loss of
contro=
l.
=20
Just over 8% of the total built have been lost to loss of
control=20
accidents.
=20
I wonder how many other people have to die or parachute to
safety=20
before someone asks the question, should this glider be flying
at all.

As the N4DM is certified, it had to be demonstrated that it will exit
a
spi=
n after 3 turn at most.=20
Loosing 1800 m in any certified glider while trying to stop the
spin is
hil=
arious. This corresponds to something like 12-15 turns.
Something has gone
=
wrong very seriously.

Bert
Ventus cM TW

Not sure that spinning is the issue per se, it is what happens after
it stops spinning that seems to be the main issue. For whatever
reason it seems that some pilots have had difficulty stopping VNE
being exceeded in the recovery.
A test pilot might be able to demonstrate a successful recovery but
what about mere mortals?

Hmmm.... maybe some of these pilots were taught, "Stick fully forward" in the spin recovery vs., "Get the nose below the horizon" instead. In a draggy trainer, they're slow to accelerate so not as much of an issue, in a "clean ship" speed happens very fast comparatively.
Some of this comes to, "Muscle memory" and whether or not good ideas were trained earlier.

I also agree, some ships do markedly different things depending on CG. Curious if there is a common CG (forward, aft?) on the accident ships.

PS, I know none of the involved pilots nor their experience, so I'm sorta guessing here.