Fatal Towplane Accident 5-9-20

On Sunday, May 17, 2020 at 4:24:19 PM UTC-7, Martin Gregorie wrote:
On Sun, 17 May 2020 15:08:51 -0700, Tom BravoMike wrote:


I think a simple mechanical device like a lever arm or cage that
extends behind the towplane for a few inches may enhance safety
significantly. Something that the tow rope would press against at a
particular angle that would activate a lever arm that automatically
opens the tow hook and releases the ring. How hard would that be to
make? It would be independent of the tow pilot, where if the tow rope
under tension pulled at greater than a particular angle to the
towplane, it would move the lever back and open the tow hook, releasing
the ring.

See what I wrote early in the thread and what response I got:

"We all know how the self-release works on the glider side at winch
launching: at a certain angle the rope puts a pressure on a lever which
causes the release. Isn't it technically simple to have a similar
solution on the tow plane side, a lever above the rope, which pressed at
kiting would release the rope immediately? Where am I wrong?"

Nobody has yet referred to the series of experiments carried out in 1978
and 1982 by Chris Rollings at Booker in the UK. I've just put a copy of a
summary report he wrote some time after 2000 on my website:

https://www.gregorie.org/gliding/kiting_on_tow

This describes both sets of tests as well as a his explanation of why, in
his opinion, an automatic release based on line angle is unlikely to
work.

IIRC this is not the original report, which I've never seen. If anybody
reading this has seen an earlier version, especially one with diagrams or
photos in it, please post a link or give a reference if its in a gliding
magazine.


--
Martin | martin at
Gregorie | gregorie dot org

Interesting read. It still leaves open the possibility of using acceleration and rotation sensors (MEMs) to profile a kiting incident and cut the rope (as mentioned earlier in this thread). It would be easy to record those values (at altitude) with a simulated kiting.

Then we need a reliable rope cutting device, triggered electrically by the MEMs circuit. I just did a conceptual exploration of a guillotine that uses a .22 cal short blank to actuate the blade. I know nothing about guns or munitions, but I am sure someone here has better suggestions for a firing mechanism, released by a melting fuse wire. The firing pin mechanism should be modular and sealed, so replacement is simple and reliable.

Please see screen shots here. As I said, it is all conceptual, and I am looking for input/suggestions. Fire away... https://www.dropbox.com/sh/8o6sbwho3...yO9ts-Voa?dl=0

Matt