Crouch Strap story

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 :

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 :

Alan Silver is very much still in business. See http://www.pia.com/silver/
-Bob Korves
LAK-17a "5K
DuoDiscus "5H"

"Dusty" wrote in message
m...
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.

On Sunday, June 6, 2004 9:26:17 PM UTC-5, Bob Korves wrote:
Alan Silver is very much still in business. See http://www.pia.com/silver/

That pia URL seems faulty. I have the following URL for Allen Silver's 5 point harness and you can order the crotch strap as a separate item.

http://silverparachutes.com/acrobelt/

BTW: We had Allen as a speaker at the ChicagoLand Glider Council's bi-annual conference and he was GREAT. http://silverparachutes.com/safety-seminars/

- John

Alan Silver

http://www.pia.com/silver/

We only send our parachutes to him. He is still repacking and making
belts.

This thread is making me wonder about if it was a good idea to get rid
of that crotch strap.

Garret

I use a 4-point for positive G (only) aerobatics and have
found that with the shoulder harnesses placed at the right height,
a fairly firm cushion, and the belts tightened REAL
tight, I feel VERY secure.

For me setting up cushions and chute and harnesses in such a way
that I have excellent reach for everything, excellent vis, and
am yet quite snugly held in seems to make me feel secure.
I have a little trouble resnugging if I have to shift or
unbuckle momentarily, but it only seems to take
a few tries to get it back.

Ommitting for the moment the idea that perhaps 5 or 6 points might
be better, I wonder how important snugging it up is instead.
I've always assumed that very tight is better than
not, but haven't really heard much opinion. There was some cushion
discussion a while back and I have a fairly thick, fairly firm cushion
now (fortunately I'm quite short so no canopy issues). But
what about snugging tight? Anyone with thoughts or stories?

In article ,
Martin Gregorie wrote:
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
--

------------+
Mark Boyd
Avenal, California, USA

On Sun, 06 Jun 2004 19:50:01 +0100, Martin Gregorie
wrote:

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

Following myself up: I've just been speaking to Willans Harnesses
(both the Stockbridge Racing operation and Willans Harnesses, the
division that used to do glider harnesses).

Stockbridge said that under no circumstances would they sell any of
their harnesses or upgrades for gliding use and quoted both
certification and product liability as the reasons for this.

Willans Harnesses do custom harnesses and tree climbing equipment and
used to make gliding harnesses. They no longer do glider harnesses in
any shape or form because the cost and time involved in obtaining JAR
certification was so great that they saw no nett benefit to themselves
in obtaining it.

It appears that Schroth is currently the only game in town on this
side of the pond.

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

"Martin Gregorie" wrote in message
...

Willans Harnesses do custom harnesses and tree climbing equipment and
used to make gliding harnesses. They no longer do glider harnesses in
any shape or form because the cost and time involved in obtaining JAR
certification was so great that they saw no nett benefit to themselves
in obtaining it.



Martin.

These belts do not conform to the TSO from the FAA either.
It's an American process to allow and document minor alterations
to the glider on a form 337 for Type Certificated aircraft. There
may be a similar process available to you poor souls across the pond.
Ask you administrator (I don't know what you call them) or the BGA
if there is a process similar to a Form 337/field approval for you to
follow.
I suspect that there is. The JAR regs are so close to the FAA regs in most
regards
that I suspect you can get it accomplished.

Scott.