Le vendredi 1 mai 2020 17:15:05 UTC+2, Dave Walsh a écritÂ*:
At 20:45 30 April 2020, Dave Nadler wrote:
On Thursday, April 30, 2020 at 10:48:55 AM UTC-4, Jonathan St.
Cloud wrote:
Someone please correct me if I am wrong but I believe
only 4 Arcus E's were sold and one of those was written off in an
accident?

Those are correct numbers (at least as of a few months ago).

The Arcus E has a pretty high wing loading; the one that crashed was
flying near Barcillonette in the southern French Alps, it appears to
have spun in. Neither pilot survived. It's not known whether the wing
loading was a significant factor.
Spinning any open class glider seems to be a hazardous. JM Clement,
who has very extensive gliding experience, is of the opinion that
none of them can be safely spun.

The Arcus is not an Open Class glider.
Spinning an Open Class glider is suicidal. The moment of inertia of the wings is 3-4 times higher than that of a 15 m glider, but the rudder isn't. That makes that stopping the rotation takes significantly more time than in a small ship, and during this unstalling process the ship starts to accelerates. After the rotation has stopped, there are two choices: Exceeding v_ne, or exceeding max g-load above v_d.
Stupid enough to have been there and done that, lucky enough that the glider was stronger than the designer had expected.