Dale Thompson and I had an inverted V crotch strap in our 1-35. It served to
keep the lap belt in position. More important was the assurance that the
legs and hips would probably take the stress instead of other more
"important" parts that could not be so easily repaired.

Fortunately, we never had a test of its effectiveness.

The design is very simple and easily made. Our was made by Alan Silver, in
the San Francisco bay area, who repacked our chute. I do not think he is
still in business.


"Martin Gregorie" wrote in message
...
On 6 Jun 2004 16:55:50 GMT, Ian Cant
wrote:

The 'crotch strap' is what used to be known as a 'negative-G'
strap. Usually it works to keep your skull away from
the canopy during the bumpy bits of sky; rarely, it
helps you in a crash by preventing submarining. However,
a single strap is both inconvenient and potentially
painful. A better design is a double strap, like an
inverted V, but it needs two hard points. Another
variation is an upright V, with one hardpoint and some
secure way to fasten the ends of the V to the lapstraps
rather than the buckle.

I followed the link to Willans Harnesses in "plastic guy's" post and
moused round the site a little. They supply a Y-strap that's designed
to connect to the 5th slot on their quick release fitting, passes
under your legs and attaches to the lap strap hard points. They say
its designed to upgrade their 4-point racing car harnesses to 6-point
standard.

This looks potentially like a quick and easy way to upgrade a 4-point
harness because it requires no extra hard points in the glider.
Presumably the lap strap hard points are already designed to take the
full deceleration loads in a crash so fitting it would not put
additional loads on them.

Does anybody on here know if this upgrade has been done?

If so, how does it compare with a traditional 5-point system with
regard to anti-submarining and negative-G properties?

Are our 5-point rotary action quick-release units the same as the car
racing gang use?


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :