Crotchless Accoutrements

I don't have a fifth strap in my ship and came up with a way to improve the effectiveness of the stock shoulder belts.

I installed a big D ring at the anchor point of the lap belts.

An additional strap was constructed with loop at one end ... it is used as shown in the photo.

This is a photo of the prototype and we have a lot of extra belt material - you can adjust for your specific ship to keep it neat.

You can pull the belts very tight and they hold tension well ... pressure on your shoulders is close to that of a crotch strap (so tight it hurts)... but not quite as neat as you do have two extra pieces of webbing. Everything releases if you have to exit. So, perhaps a reasonable solution until you install that fifth belt.

http://designtekk.com/photos/RidgeStrap.jpg

We also tested putting the D rings on the lap belts - the part you pull on to tighten. This worked fairly well if the rings were located close to the slider ... plus the arrangement seemed to keep the lap belts tensioned.

I have some extra rings and webbing from the prototyping session and would consider supplying at cost ... or you can DIY.

KK

At 13:27 22 June 2014, KiloKilo wrote:
I don't have a fifth strap in my ship and came up with a way
to improve
the=
effectiveness of the stock shoulder belts.

I installed a big D ring at the anchor point of the lap belts.

An additional strap was constructed with loop at one end ... it
is used as
=
shown in the photo.

This is a photo of the prototype and we have a lot of extra
belt material
-=
you can adjust for your specific ship to keep it neat.

You can pull the belts very tight and they hold tension well ...
pressure
o=
n your shoulders is close to that of a crotch strap (so tight it
hurts)...
=
but not quite as neat as you do have two extra pieces of
webbing.
Everythi=
ng releases if you have to exit. So, perhaps a reasonable
solution until
yo=
u install that fifth belt. =20

http://designtekk.com/photos/RidgeStrap.jpg

We also tested putting the D rings on the lap belts - the part
you pull on
=
to tighten. This worked fairly well if the rings were located
close to
the=
slider ... plus the arrangement seemed to keep the lap belts
tensioned.=20

I have some extra rings and webbing from the prototyping
session and would
=
consider supplying at cost ... or you can DIY. =20

KK

That arrangement produces a side force that alters the angle of
the shoulder straps over the upper body (which I would like),
and the extra thickness from the red strap going through the
upper buckles may well reduce slippage, but as for being able
to increase the downforce on the shoulder straps more than
simply tightening them directly - it's difficult to see how that
can happen when the lower and upper anchor points for the red
strap are both attached to the same black shoulder strap.

The same would apply if the lower end of the red strap were to
be attached to the lap strap because the shoulder and lap straps
are co-located on the main buckle which can ride up.

I think it is ridiculous that all gliders don't come with 5th strap
and a buckle designed to allow it to be independently and
safely detached when required for in-flight comfort
considerations.

JG

John,

The D-rings effectively become attachment hard-points which do not allow the shoulder belts to move upward any distance under load ... which is what the fifth strap does when installed.

The setup is flight and ridge tested ... it works great ... just not as dead simple and convenient as a fifth belt.

kk

On Sunday, June 22, 2014 11:55:19 AM UTC-7, KiloKilo wrote:

The setup is flight and ridge tested...

Please let us know when it has been crash tested.

Thanks, Bob K.

On Sunday, June 22, 2014 10:41:58 PM UTC-4, Bob Kuykendall wrote:
On Sunday, June 22, 2014 11:55:19 AM UTC-7, KiloKilo wrote:



The setup is flight and ridge tested...



Please let us know when it has been crash tested.



Thanks, Bob K.

Will do ... thanks ... kk

On Sunday, June 22, 2014 9:27:57 AM UTC-4, KiloKilo wrote:

http://designtekk.com/photos/RidgeStrap.jpg

An interesting and innovative approach. I can see how this would make the shoulder straps more effective.

With no criticism implied, I'd offer the following observations: the tension on the vertical maroon strap is translated to a horizontal pull via the D-ring to the shoulder strap tabs and the central quick release mechanism. The tabs and mechanism are designed for a load that is aligned axially with the shoulder strap. In sink, the maroon strap periodically imposes a horizontal tug on the tab perpendicular to the load for which this connection was designed.

Since the quick release mechanism is precisely machined, I'd be concerned about gradual distortion and also wear from metal on metal rubbing that might lead to gradual or catastrophic failure of the mechanism. One scenario would be an apparently secure latching that fails under a peak load. A second failure scenario would be a jammed and not-so-quick release. A third failure scenario would be an unintentional release of the tab coincident with a horizontal tug. I'm not saying that any of these scenarios will occur, I'm just offering food for thought.

An alternate solution that might work for you...I attach the thigh straps of my 6-point harness to the lap belt anchor points with 5000 lb test tubular flat climbing webbing. It works well for my glider and body. The loads imposed on the anchor points are very similar to the load imposed by the original 4-point harness. The 6-point harness rigged this way works much better than the 4-point. My harness might work a bit better if the anchor points were closer to the center of the glider and a bit farther forward, but since it works well so far in strong turbulence, I have no plans to add additional anchor points.