S-H safety harness (V2C)

An annoying property of my Ventus 2C is that the safety harness does
not hold me into the seat. When encountering turbulance my upper torso
leaves the seat and my head ocassionally hits the canopy.

The position of the shoulder strap anchors aft of the cockpit is high
enough that no downward force is exerted no matter how much the straps
are tightened. The only thing this achieves is pulling the buckle up
away from my abdomen.

Are there any solutions or workarounds for this prollum? (Besides
padding my hat?)

~ted/2NO

Ted,

You did not say what system you have. If you have a four point, I would
recommend upgrading to a six point harness. I did that on my Nimbus 2
and was the best investment I ever put in a glider. Will be doing the
same in my Ventus this summer.

I could run the ridge and near Vne final glides after that I was not
comfortable before.


Tim

I had a 5th attachment point installed in my ship and it was a
considerable improvement over the 4 point original equipment harness.
The crotch strap holds the lap belts in the proper position vertically
such that, once they're tight, I don't move up or forward at all; very
nice!.

Ray Warshaw


TTaylor at cc.usu.edu wrote:
Ted,

You did not say what system you have. If you have a four point, I would
recommend upgrading to a six point harness. I did that on my Nimbus 2
and was the best investment I ever put in a glider. Will be doing the
same in my Ventus this summer.

I could run the ridge and near Vne final glides after that I was not
comfortable before.


Tim

wrote:
I had a 5th attachment point installed in my ship and it was a
considerable improvement over the 4 point original equipment harness.
The crotch strap holds the lap belts in the proper position vertically
such that, once they're tight, I don't move up or forward at all; very
nice!.

I agree absolutely with the above.

For peeing in the air you just temporaraily loosen or disconnect the
crotch strap, I find no problem in this in my Nimbus. But remember to
re-connect and tighten it again! Not too tight, though, on a long
flight, comfort is a positive flight safety factor, discomfort is the
opposite. But tighten all straps before landing!

Correctly-positioned lap-straps take the main load in an ground-impact
situation, shoulder straps prevent the body from "jack-knifing" and the
fifth (crotch) strap keeps the lap straps from riding up the body
during flight. If the latter happens, in a situation of high
longitudinal deceleration, the body "submarines" under the lap strap
and high damage or worse can be done to the lower limbs or torso.

In my opinion, all glider seats should have a five- (or six-) point
harness for the above reasons. Even more important in gliders with
reclining or semi-reclining seats.

There was much discussion on this a few years ago on this newsgroup. A
report by a German Automotive engineer criticised the glider crotch
strap for the alleged possibility of damage to the testicles in an
impact. German manufacturers and others "took fright" and then refused
to fit five-point harnesses. This position has fortunately now been
reversed as a result of subsequent tests and reports by aviation
experts.

I and others such as Doctors Peter Saundby and Tony Segal in the UK
became involved. As an ex military pilot used to riding on ejection
seats with 5-point harnesses, I always thought that in a glider
life-or-death impact, sore balls for a few days (if indeed that
happened, which is questionable) were a better alternative to becoming
a paraplegic or dead. Dr Saundby, an experienced glider pilot and
military pilot and flight surgeon and the BGA Medical Advisor, pointed
out that the crotch strap was there, not so much to take load, but to
hold the load-bearing thigh straps in their correct position before
impact.

Dr Segal was able to carry out glider cockpit drop-tests in
co-operation with a number of other organisations such as the UK
Ministry of Defence R&D agency (now QintetiQ). These used old cockpits
and instrumented mannikins. The results were very much in favour of
having that crotch strap, for the reasons above. The Segal tests were
reported in UK magazine Sailplane and Gliding and a longer official
report was also published. Someone may be able to dig up the
references.

So, anyone with a reclining seat glider and only a four-point harness,
I would seriously consider carrying out an officially-approved mod to
fit that crotch strap!

Ian Strachan
Lasham Gliding Centre, UK

Ian and others across The Pond,

I'd very much be interested in seeing the reports mentioned. Heck, I'd
even be willing to pay for a copy (a novel idea I know). If anyone is
willing to take this on, please contact me directly.

Erik Mann
LS8-18 (dedicated "6-pointer")

I wandered around the web sites for Schroft, Gadringer, Davis and
Pacific Scientific today. For aircraft, they only appear to offer 3, 4
or 5 point harnesses. None of them offered 6 point harnesses for
aircraft. Schroft does indeed make 6 point harnesses, but these
harnesses are intended for motor racing and only carry FAI
certification, not LBA or FAA certification.

Wouldn't it be a violation (in the USA) of some FAR to fly a type
certificated aircraft with a safety harness that didn't carry either
FAA or LBA certification?

-John

Eric, from a pevious posting on r.a.s. I turned up the following:

Title of paper:
Four and Five Point Glider Seat Harnesses - Static and Dynamic Tests

Authors
Dr Anthony M Segal, Lasham Gliding Society, UK
Leslie P Neil, Senior Engineer Impact Protection, UK DERA
Graham A Reece, Instrumentation Engineer, UK DERA
Philip G Murtha, Impact Test Track Engineer, UK DERA
(DERA = UK Defence Evaluation and Research Agency)

This paper was presented to the gliding scientific organisation
OSTIV during their meeting at Bayreuth, Germany, in August 1999
and no doubt will be available in full from OSTIV
(OSTIV = Organisation Scientifique et Technique Internationale de
Vol a Voile).

The paper is 20 pages long but para 5b is worth quoting in full
(QRF = Quick Release Fastening, that is, the harness release box)::

"5 b) Observations After the Impact Test
When a 5 point harness was being tested, both with the harness tight
and with the harness slack, the lap straps remained in the
correct position over the hip bones. The QRF also stayed
in the correct position.

When a 4 point harness was being tested, both with the harness tight
and with the harness lose, the lap straps were seen to have moved up
over the abdomen until they were jammed tightly under the lower rib
margin.
The QRF had moved upwards until it was in the epigastrium
(the "pit of the stomach"). This is very serious, because severe,
even fatal injury may be caused to the internal organs in the upper
abdomen.

This is considered to be the most important finding of the entire
test.

Following the impact test, with a 4 point harness, the shoulder straps
were seen to be hanging loosely between the seat back and the pilot
dummy's shoulders. This was due to the upward movement of the
lap straps and the QRF."

Finally, the conclusion includes the following words:

"A 5-point harness is superior to a 4-point harness in an accident
impact situation and also under conditions of negative-g. This is
especially so if the harness is slack."

It also goes on to say: "The 5th strap should be fitted to new gliders
and be retro-fitted (where structurally feasible) to gliders
in current use".

-------- end of quotes --------

Hope this helps

Ian Strachan

I have a 4-point system. What's involved with getting a 6-point
harness?

Ray: how do you reconcile a crotch strap and a pilot relief system?

I use a "condom" style catheter with a collection bag strapped to my
leg; no spills and a large capacity. It's sold on-line by an outfit
called Stadium Pro. The fifth strap, if the attachment is correctly
placed, doesn't touch your privates; it's sole function is to keep the
lap belts in proper (low) position. I expect the fifth strap would
interfere with a pee bag or funnel system, though.

Given my somewhat plump body habitus, I'm highly (largely?) unlikely to
submarine under the lap belts. Someone more svelt might want to
consider the physics of having one's forward motion stopped largely by
that fifth strap, however.

Ray Warshaw
1LK

Flying a Ventus C with a 5 point system and an external catheter
linked to a dump tube exiting on the lower gear door.

When I need to use the system I unlock the gear to lower the doors,
and loosen the crotch strap. When finished I blow out the line with a
longer tube tee'd into the dump line, raise the gear, and tighten the
crotch strap.

Works fine.

Bob

On 24 Apr 2006 17:28:53 -0700, wrote:

I use a "condom" style catheter with a collection bag strapped to my
leg; no spills and a large capacity. It's sold on-line by an outfit
called Stadium Pro. The fifth strap, if the attachment is correctly
placed, doesn't touch your privates; it's sole function is to keep the
lap belts in proper (low) position. I expect the fifth strap would
interfere with a pee bag or funnel system, though.

... text deleted

Ray Warshaw
1LK