Crouch Strap story

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.

For me six point harness is far preferable to a five
point one which would simply be impossible for long
flights. The borrowed Std Cirrus I fly at present
has a non-approved 6 point harness designed for race
car use that uses a 4 point buckle and no additional
attachment points. I think it is a little different
from that described in the earlier post.

The shoulder and lap straps are as normal except that
there is a strong metal ring attached to the top of
each lap strap about 3 inches lateral to the buckle.
The 4th and 5 straps are attached by metal clips under
the seat pan to the fuselage (not seat pan) mounted
attachment points also used for the lap straps. The
upper, business, end of the 2 thigh straps is a loop
not a buckle. The straps run forward and medially
under the seat pan for about 8 inches and emerge through
slit shaped cut outs in the seat pan under the inside
of each upper thigh - giving virtual attachment points
there. With only the laps straps buckled the left
thigh strap comes inside and over the thigh to the
metal ring over the top of the thigh, through it and
then turns upwards and inwards towards the top of the
buckle area. Then the metal tongue of the left left
shoulder strap is inserted throught the thigh strap
loop and into the buckle. Same on the right.

This arrangement pulls down on the lap strap assembly
from the top strap's tongue but the extra straps come
in at an angle from the side and do not cover the buckle.
When the buckle is undone the shoulder straps are
instantly free of the 4th and 5th straps which just
fall away through the metal loops on the lap straps.

When we first looked at the glider we did not understand
that the extra straps attached to the shoulder straps
and thought they were suppsed to attach to the lap
straps which would not have been easy to get out of
in a hurry. I only refitted the extra straps today
as a result of thinking about this thread and it seems
to work really well. I feel secured firmly in the
seat pan and can't slide forward. The lap straps are
held well down in place and at last I don't have to
feel squashed down by shoulder straps - which can be
safely left comfortable. I will be able to pee no
problem too.

I recall from attempts to get six point straps fitted
to a new glider about 3 years ago that the manufacturer's
view was that it was impossible for them as there were
no LBA approved 6 point straps. Damn shame.

John Galloway

Excellent post Ed....thanks for sharing it with us. I hope that you are
doing well.

I remember Chip showing us his system years ago when flying at Mid Atlantic
Soaring. My only concern is the same that was posted back when this all was
discussed in 1998....that is if the belts will withstand the loads placed
upon them at angles that they were not designed for when using the system
described by Chip. Does anyone have any further info about this? You out
there Chip? I know that he was concerned re the liability issue of
non-approved applications in the past so may not be willing to discuss this
publicly.

I have a crotch strap installed by myself in my experimental certificated
glider (LS-8) but honestly only use it when on a fast final glide to keep my
head from being bruised i.e. most of the flight it is not connected for
relief reasons. It obviously wouldn't be much help laying there in the seat
just prior to impacting something.

Casey Lenox
KC
Phoenix

"Kilo Charlie" wrote in message news
I remember Chip showing us his system years ago when flying at Mid Atlantic
Soaring. My only concern is the same that was posted back when this all was
discussed in 1998....that is if the belts will withstand the loads placed
upon them at angles that they were not designed for when using the system
described by Chip. Does anyone have any further info about this? You out
there Chip? I know that he was concerned re the liability issue of
non-approved applications in the past so may not be willing to discuss this
publicly.

I still use my 6-point harness, the details of which I discussed in a
previous posting. Ed Byars' thoughtful email prompted me to look for
it. Cut and paste this URL into your browser window. You may have to
remove any hard carriage returns that have been inserted into the long
address:

http://groups.google.com/groups?q=gr...aol.com&rnum=1

My concern about modifying harnesses in a certified aircraft remains,
not just for regulatory reasons but also because you're touching a
piece of safety-related equipment that can carry high loads and has
the potential to save your life and/or injure you, as Tim Mara has
previously noted on this forum.

As Casey notes, many 6-point installations (including mine) use the
seat belt attach points to anchor the thigh straps, too. I agree this
raises a question about loads being applied with different vectors
than they were designed for. On the other hand, approximately 50% of
the load on the extra harness straps is fed into the central buckle
which has the shoulder harness restraining it, so it's not as bad as
it first seems. I'd welcome any comments from more authoritative
sources.

In one update since I wrote the above email, several pilots have
assured me that their 6-point harnesses work just as well as a 5-point
harness (i.e., with a crotch strap) for turbulent ridge running. I was
a little dubious but, having never used a crotch strap, I have no
first-hand knowledge.

Chip Bearden

ED
Glad you're doing well. I am curious--did the crotch strap attach point
fail, or was it intact after the crash? If it did fail, at what estimated
load did that occur? Pehaps it does not have to hold the entire load to be
effective--your thoughts?
Thanks

Hartley Falbaum


"Ed Byars" wrote in message
hlink.net...
I sent the following to our magazine nine months ago and didn't receive an
acknowledgement or receipt. I guess it was not suitable for them so I
thought I would share it with ras to maybe provoke some safety discussion.

efb10-11-03-rev.6-5-04

You may be interested in my latest crotch strap experience.

I'm still analyzing my June 2003 accident and the cause. More later on
this.
The role of the crotch strap is significant and worthy of mention.

The last half dozen gliders I've had I added a crotch strap (usually
available from Wings & Wheels), which easily clicks into the bottom, front
or 5th slot of the standard Gadringer belt hardware. I secure the other
end,
which terminates with the belt into a triangular link, with a quarter inch
hole that I bolt to the seat pan with a large "wood" washer behind the
seat
pan. My gliders are Experimental category so this is legal.

I always heard that the main purpose of a crotch strap was to keep the lap
belt across the upper thighs and prevent it sliding up to the stomach
area.
I have since learned better.

It of course depends on the direction of the accident loads and the
direction of the inertia of the body as to how all restraint straps come
into play.

Many glider accidents involve "dropping in" vertically wherein the
tailbone
(in the L-1, L-2 area) or higher are damaged so the belts don't help much.
You seldom see accidents with lap belt overload, but it happens. I have a
sad memory of helping remove a dead friend from an inverted Ventus cockpit
where the lap belts on both sides had pulled lose from the seat pan.
Fortunately rare but it happens.

In my "incident" the nose of the glider hit hard ground at about a 60 plus
degree angle. The "load" was about along the longitudinal axis of the
glider. Since in our modern gliders (ASW-28 in my case) we recline (sit
supine), the inertia of my body was toward the nose with only the crotch
strap to resist. Actually Waibel designed the seat pan to take some of
this
forward load against the bottom of the thighs. In this seating the knees
are
bent more upward.

The nose of the glider (along with my feet) was crushed in a calculated
energy-absorbing manner. Thank you Gerhardt Waibel! I think his design
and
the crotch strap saved my knees.

I was conscious and lucid until the helicopter dropped me off at the
Medical College of Georgia Trauma Center.

After that I really was not with it for a couple of weeks, but after that
time I suddenly noticed that my groin area was still quite swollen. I
realized that my crotch area had sustained a significant load and that all
things considered had kept my body from moving more forward and no doubt
helped minimize the leg/knee damage. I had no shoulder strap or lap belt
marks or soreness.

Since my guess is that a significant number of glider accidents impose
loads
and body reactions similar to mine, I recommend a crotch strap. Trying to
distribute the load to the pelvic area by wearing an athletic "cup" may be
good for some flights, but for some flights there are other disadvantages.
Many contest pilots regularly wear a male external catheter and I don't
think both would work. With just the crotch strap I always had to be
careful that the strap was adjusted somewhat to the right, was not too
tight, and did not interfere with the flow from the catheter that was to
the
left.

I suggest reading Chip Bearden's posting which appeared in the
rec.aviation.soaring newsgroup on Nov.20 1998 which outlines a more
complex
but better seat belt design.

I hope this discussion will create more thought about glider accident
safety.

Ed Byars

Hi Hartley,
The crotch strap remained intact after doing it's job. I'm just lucky that
no serious permanent damage was done to my sensitive genitals.
I like the ideas presented relative to a six point arrangement. This sure
sounds safer, but any sensible arrangement would be virtually impossible to
get by the LBA/FAA.
It's a shame that it's not likely that any competent person or group
would/will develop and offer for sale such a glider system. Our legal system
just would not allow it. Maybe such a system designed for another more
numerous vehicle, auto probably, might be available for Experimental
licensed gliders. From an overall safety standpoint it may be just as
important to assure that any belting system is quickly free of the body with
one quick push or twist. We must not forget that provision for a quick
cockpit egress may be just as important.
I'm pleased that this thread seems to have made a few of us review our
restraint system and think about possible improvement.
Ed Byars


"HL Falbaum" wrote in message
newsuPwc.19014$%F2.12354@attbi_s04...
ED
Glad you're doing well. I am curious--did the crotch strap attach point
fail, or was it intact after the crash? If it did fail, at what estimated
load did that occur? Pehaps it does not have to hold the entire load to be
effective--your thoughts?
Thanks

Hartley Falbaum


"Ed Byars" wrote in message
hlink.net...
I sent the following to our magazine nine months ago and didn't receive
an
acknowledgement or receipt. I guess it was not suitable for them so I
thought I would share it with ras to maybe provoke some safety
discussion.

efb10-11-03-rev.6-5-04

You may be interested in my latest crotch strap experience.

I'm still analyzing my June 2003 accident and the cause. More later on
this.
The role of the crotch strap is significant and worthy of mention.

The last half dozen gliders I've had I added a crotch strap (usually
available from Wings & Wheels), which easily clicks into the bottom,
front
or 5th slot of the standard Gadringer belt hardware. I secure the other
end,
which terminates with the belt into a triangular link, with a quarter
inch
hole that I bolt to the seat pan with a large "wood" washer behind the
seat
pan. My gliders are Experimental category so this is legal.

I always heard that the main purpose of a crotch strap was to keep the
lap
belt across the upper thighs and prevent it sliding up to the stomach
area.
I have since learned better.

It of course depends on the direction of the accident loads and the
direction of the inertia of the body as to how all restraint straps come
into play.

Many glider accidents involve "dropping in" vertically wherein the
tailbone
(in the L-1, L-2 area) or higher are damaged so the belts don't help
much.
You seldom see accidents with lap belt overload, but it happens. I have
a
sad memory of helping remove a dead friend from an inverted Ventus
cockpit
where the lap belts on both sides had pulled lose from the seat pan.
Fortunately rare but it happens.

In my "incident" the nose of the glider hit hard ground at about a 60
plus
degree angle. The "load" was about along the longitudinal axis of the
glider. Since in our modern gliders (ASW-28 in my case) we recline (sit
supine), the inertia of my body was toward the nose with only the crotch
strap to resist. Actually Waibel designed the seat pan to take some of
this
forward load against the bottom of the thighs. In this seating the knees
are
bent more upward.

The nose of the glider (along with my feet) was crushed in a calculated
energy-absorbing manner. Thank you Gerhardt Waibel! I think his design
and
the crotch strap saved my knees.

I was conscious and lucid until the helicopter dropped me off at the
Medical College of Georgia Trauma Center.

After that I really was not with it for a couple of weeks, but after
that
time I suddenly noticed that my groin area was still quite swollen. I
realized that my crotch area had sustained a significant load and that
all
things considered had kept my body from moving more forward and no doubt
helped minimize the leg/knee damage. I had no shoulder strap or lap belt
marks or soreness.

Since my guess is that a significant number of glider accidents impose
loads
and body reactions similar to mine, I recommend a crotch strap. Trying
to
distribute the load to the pelvic area by wearing an athletic "cup" may
be
good for some flights, but for some flights there are other
disadvantages.
Many contest pilots regularly wear a male external catheter and I don't
think both would work. With just the crotch strap I always had to be
careful that the strap was adjusted somewhat to the right, was not too
tight, and did not interfere with the flow from the catheter that was to
the
left.

I suggest reading Chip Bearden's posting which appeared in the
rec.aviation.soaring newsgroup on Nov.20 1998 which outlines a more
complex
but better seat belt design.

I hope this discussion will create more thought about glider accident
safety.

Ed Byars

"Ed Byars" wrote in message
Hi Hartley,
The crotch strap remained intact after doing it's job. I'm just lucky that
no serious permanent damage was done to my sensitive genitals.
I like the ideas presented relative to a six point arrangement. This sure
sounds safer, but any sensible arrangement would be virtually impossible
to
get by the LBA/FAA.
SNIPPED


Ed.
Installing the belts in a sailplane is an exceptionally simple procedure.
If experimental, just do it.

If certified, file a 337 and get the field approval for the airplane you
stick it in.

Its quite simple to do and I haven't met a MIDO guy that didn't stamp it off
immediately
and wonder why they weren't there to begin with.

Scott.