S-H safety harness (V2C)

[[email protected]]

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

[TTaylor at cc.usu.edu]

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

[Greg Arnold]

wrote:
> 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
>

Same problem in my Discus A. There is space between the shoulder straps
and my shoulders.

[[email protected]]

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

[[email protected]]

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?

[[email protected]]

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

[Bob Gibbons]

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
>

[Bert Willing]

Shoulder straps are supposed to hold you back from moving *forward*. Belly
straps are supposed to hold you *down*. The crotch strap is suppposed to
keep the belly straps in position.

"Greg Arnold" .> wrote in message
news:lI83g.3806$_c1.175@fed1read05...
> wrote:
>> 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
>>
>
> Same problem in my Discus A. There is space between the shoulder straps
> and my shoulders.

[Edward Lockhart]

At 19:18 24 April 2006, wrote:
>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've never seen a six point for real but this is what's
involved:
http://www.lukeracing.co.uk/anat.php
There's also this company:
http://www.willansharness.com/

I think straps 5 & 6 are attached to the same hardpoints
as the lapstraps and prevent the buckle from sliding
up every time you tighten your shoulder straps.

Edward

[[email protected]]

wrote:
> 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-
Design is done that way to prevent compression of spine in an accident.
Solution to your problem as noted elsewhere is 5th point holding seat
belts down and forward. Your belt should have provisions for this 5th
point in the latch.
Good luck
UH

[Papa3]

Ray,

I know (hope) your statement was tongue-in-cheek, but it is worth a
comment. Your "spare tire" (or even your six-pack abs) won't prevent
you from submarining. Your lap belts must be and stay securely
locked down on your pelvis. I have an article from one of the auto
racing labs which shows that your pelvis can withstand 5,000 lbs of
force whereas the soft organs of your gut will be severely compromised
at less than 800. Assuming in a crash that the straps around your
middle take 50% of the load (obviously, that will depend on many
factors - crash angle, deceleration mode, etc. etc.), that still means
that anything approaching an 8g deceleration (maybe less) will be
serious trouble. Now, that's an otherwise survivable crash, so it
would be a shame to have a problem. Especially in the older,
flatter seat pans, it doesn't take an especially creative mind to
visualize the submarining that happens without a properly secured lap
belt.

Erik Mann
LS8-18 (P3)

[[email protected]]

Erik,

It was, although "butt in sling" or something similar might better
"fit" the situation. The whole point of that 5th strap is to keep the
lap belts properly positioned on the pelvis and still allow the
shoulder belts to be tight. This positioning gives the best control of
both vertical and horizontal motion. In the case of a really high g
impact in a glider I suspect restraint issues would be moot, however.

There's been a lot of research on making high speed racecar crashes
survivable; there's both interest and funding for it, very little on GA
and only a bit in gliders. The key lessons from Nascar and Grand Prix
racing are that a cockpit that maintains its integrety and a restraint
system that keeps the driver within that container are good things.
Nascar has now mandated a separate head restraint to prevent neck
injuries. These measures have made at least some 200 mph crashes
survivable.

Bringing measures of this kind to gliders would require that we be
willing to pay for them, something, according to the DG newsletter, we,
as a group, are not willing to do.

Ray Warshaw
1LK

[[email protected]]

Properly positioned lap belts control both vertical and horizontal
motion. The shoulder belts keep the torso from pivoting forward and
the crotch strap keeps the lap belts in place. Note that the crotch
strap need not actually contact your crotch to properly perform this
function. My recollection of the racecar research is that, in a
reclined seating position, a substantial portion of the force on the
shoulder belts is transfered downward and captured by the lap belts.

Ray Warshaw

[[email protected]]

I'm going to give this 5th point thing (crotch strap) a try but I'll
have to have the anchor point on the seat pan just below the stick boot
around where the factory relief tub hole is drilled. (I made a new hole
for that several inches farther aft.)

Thanks to everyone who responded by e-mail, I appreciate it very much.

~ted/2NO

[[email protected]]

Go to groups.google.com and do a search for the "Glider harnesses, 4
versus 5-point" thread back in 1998. There is some specific information
about the pros/cons of various types of safety harnesses and how to
modify existing gliders.

Chip Bearden
ASW 24 "JB"

[Ian Strachan]

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

[Papa3]

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")

[jcarlyle]

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

[Robert Hart]

TTaylor at cc.usu.edu wrote:
> I think if you purchase most of the Schroth belts made with the fifth
> point space you can convert it to six point without being concerned
> about violating the FAI certification for a standard airworthiness
> aircraft. The main part of the belt will carry the correct id. I
> would do it that way if I was worried about airworthiness certificates.
> In the experimental category you have a little more latitude to use
> the FAI approved belts.

I have been reading this thread with interest.

I (part) own a Nimbus 2c and have experienced problems with the very
high attachment point of the shoulder straps resulting in smashing the
canopy with my head!

(See http://www.hart.wattle.id.au/alice/articles/alice27jul02.html for
the details and photos)

Whilst a 5 (or 6) point harness will stop 'submarining' under the lap
strap (which hasn't appeared to be a problem) it does nothing for the
problem caused by having the attachment point of the harness so high (at
the shoulder level and only just behind the shoulder at that.

This position means that even with the straps cinched up tight, my upper
body can still lift considerably when I hit turbulence. In order to
avoid hitting the canopy hard, I must use a very prone seating position.

If anyone with a Nimbus 2 has found a way of overcoming the poor design
of the strap attachment points, I'd love to hear. We have searched for a
better solution in vain!

--
Robert Hart
+61 (0)438 385 533 http://www.hart.wattle.id.au

[TTaylor at cc.usu.edu]

Robert,

Read my first note above, 6 point completely fixed the problem.
Shoulder harness is only to stop the upper body going forward, lap
belts hold you down. Once I put a 6 point in my Nimbus 2 I never
touched the canopy again. I fly some of the most rugged ridge in the
world and if it will work here it will work in any environment. I used
a Schroth system that was very easy to design the modification. I like
the Profi II-6 HANS FAI system. It can be adapted to gliders very
easily. It will be the first modification I will make to my Ventus B
this year.

Tim
Logan, UT, USA
Ventus B

[Ian Strachan]

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