seat belts and restraints

Bill Daniels wrote:

"Eric Greenwell" wrote in message

A "work around" I use is to press my body up against the belts. This
tends to reduce the "overshooting" that occurs when you are thrown
against the belts by negative G's, and reduces or eliminates the impact
with the canopy.


So, what about the idea of a pair of short, say 8", padded arms that rotate
down over each shoulder and latch in place? That would prevent the upper
body from rising and the head from snapping sideways. The latches would
release and the arms spring back when the canopy was opened.

Perhaps fixed arms could be on the canopy frame, so they would rise with
the canopy without any complications.

Another possibility would be a modified or removed seat back that would
give you more distance from your head to the canopy.

Any of these things would need careful design to ensure they don't make
other situations, like a crash, much worse.

Or maybe it's time for a different glider with a larger cockpit, or more
flexible wings!

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

If you have your head touching the canopy it cannot accelerate into the
canopy and hurt you.
-Bob

"Eric Greenwell" wrote in message
...
Bill Daniels wrote:

"Eric Greenwell" wrote in message

A "work around" I use is to press my body up against the belts. This
tends to reduce the "overshooting" that occurs when you are thrown
against the belts by negative G's, and reduces or eliminates the impact
with the canopy.


So, what about the idea of a pair of short, say 8", padded arms that
rotate
down over each shoulder and latch in place? That would prevent the
upper
body from rising and the head from snapping sideways. The latches would
release and the arms spring back when the canopy was opened.

Perhaps fixed arms could be on the canopy frame, so they would rise with
the canopy without any complications.

Another possibility would be a modified or removed seat back that would
give you more distance from your head to the canopy.

Any of these things would need careful design to ensure they don't make
other situations, like a crash, much worse.

Or maybe it's time for a different glider with a larger cockpit, or more
flexible wings!

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

If you have your head touching the canopy it cannot accelerate into the
canopy and hurt you.

Sure it can. If you hit a 3 G negative acceleration, not uncommon in heavy
ridge lift, the glider is accelerating down at 3G. Your head is trying to stay
where in one postion spatially, so the result is a force against the canopy
equal to the mass of your head times the G forces. The more dense your head,
the higher the force!

Jim Vincent
N483SZ
illspam

Hi,

Your head is trying to stay where in one postion spatially, so the
result is a force against the canopy equal to the mass of your
head times the G forces.

Minus the force your neck exerts on your head, right? Which brings
us back to restraining systems.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de
"Flying an An-2 is like making love to a fat lady who's had too much to drink:
there's a lot to work with, it's unresponsive, you're never quite sure when
you're there, and it's big-time ugly."

"Marian Aldenhövel" wrote in message
...
Hi,

Your head is trying to stay where in one postion spatially, so the
result is a force against the canopy equal to the mass of your
head times the G forces.

Minus the force your neck exerts on your head, right? Which brings
us back to restraining systems.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de
"Flying an An-2 is like making love to a fat lady who's had too much to
drink:
there's a lot to work with, it's unresponsive, you're never quite sure
when
you're there, and it's big-time ugly."

Many Eastern European gliders have toe straps for the rudder pedals which do
a good job of keeping your shins from banging the underside of the
instrument panel. The seat belt does a great job of keeping your butt in
the seat. The problem is with the shoulder straps.

Since pilots sit reclining, shoulder straps are usually angled 45 degrees to
the longitudinal axis so they are only effective in preventing the upper
torso from bending up and forward at the hip joint in a crash. They are
much less effective in preventing the upper torso, neck and head from moving
vertically in turbulence.

What if the shoulder belts crossed over the chest like bandoleers and
attached to the seat belt anchors somewhat like double automotive shoulder
straps? That seems like it would secure the upper body well but I don't
know how a quick release would work.

The idea of shoulder restraints as part of the canopy frame would work great
with front and rear hinging canopies. I can't see it working with side
hinging canopies.

Thinking about this has made me realize that what I really fear about
turbulence is a head or neck injury. I'm not really concerned about an
upset since I know I can fly out of it safely. Getting knocked out by a
blow to the head is a real concern for me.

Knowing for certain that my head couldn't touch any part of the glider in
severe turbulence would be a real comfort.

Bill Daniels

I believe that the shoulder restraints are recommended to be anchored
no more than 5 degrees below the shoulder and 30 degrees above the
shoulder in a vehicle IIRC.

In a glider I would think that the reclined position would change the
dynamics of the restraint. Because of the reclined position I would
think that there would be less of a tendency to compress the spine
when the shoulder straps are under a load. Is the 5th strap and
submerging the issue?

Would a low anchor point help with the upward motion of the pilot? How
would a low anchor point respond with a reclined seating position in a
crash?

Sounds like keeping your head intact is a primary concern and spine is
secondary?

So I am thinking 2nd set of straps with a low anchor point (for head
to canopy interference) and the standard straps to keep from
submerging (family jewels to 5th strap interference).

Steve





On Thu, 09 Dec 2004 15:34:37 GMT, "Bill Daniels"
wrote:


"Marian Aldenhövel" wrote in message
...
Hi,

Your head is trying to stay where in one postion spatially, so the
result is a force against the canopy equal to the mass of your
head times the G forces.

Minus the force your neck exerts on your head, right? Which brings
us back to restraining systems.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de
"Flying an An-2 is like making love to a fat lady who's had too much to
drink:
there's a lot to work with, it's unresponsive, you're never quite sure
when
you're there, and it's big-time ugly."

Many Eastern European gliders have toe straps for the rudder pedals which do
a good job of keeping your shins from banging the underside of the
instrument panel. The seat belt does a great job of keeping your butt in
the seat. The problem is with the shoulder straps.

Since pilots sit reclining, shoulder straps are usually angled 45 degrees to
the longitudinal axis so they are only effective in preventing the upper
torso from bending up and forward at the hip joint in a crash. They are
much less effective in preventing the upper torso, neck and head from moving
vertically in turbulence.

What if the shoulder belts crossed over the chest like bandoleers and
attached to the seat belt anchors somewhat like double automotive shoulder
straps? That seems like it would secure the upper body well but I don't
know how a quick release would work.

The idea of shoulder restraints as part of the canopy frame would work great
with front and rear hinging canopies. I can't see it working with side
hinging canopies.

Thinking about this has made me realize that what I really fear about
turbulence is a head or neck injury. I'm not really concerned about an
upset since I know I can fly out of it safely. Getting knocked out by a
blow to the head is a real concern for me.

Knowing for certain that my head couldn't touch any part of the glider in
severe turbulence would be a real comfort.

Bill Daniels

Here's a wierd idea:

Get longer wings. If the wings hit an updraft, they will
go up, and flex, but the fuselage won't go up right away,
kind of a "shock absorber." Then the wings will reflex,
giving extra thrust, and dissipating the G's. A few oscillations
later and you'll feel real queasy, but you'll have more glide
and less G's. Better all around, right?

OK, a bit off thread, but has anyone modeled this (dynamic)
interaction? Sure sure, we know about best glide, but what
about the effect of long wings flapping like a seagull in turbulence?

This does NOT seem to be the same kind of thing Gary
Osaba does in the Sparrowhawk or Carbon Dragon (with super stiff
wings), but it seems related...

Any long-wingers care to comment?

In article ,
Steve B wrote:
I believe that the shoulder restraints are recommended to be anchored
no more than 5 degrees below the shoulder and 30 degrees above the
shoulder in a vehicle IIRC.

In a glider I would think that the reclined position would change the
dynamics of the restraint. Because of the reclined position I would
think that there would be less of a tendency to compress the spine
when the shoulder straps are under a load. Is the 5th strap and
submerging the issue?

Would a low anchor point help with the upward motion of the pilot? How
would a low anchor point respond with a reclined seating position in a
crash?

Sounds like keeping your head intact is a primary concern and spine is
secondary?

So I am thinking 2nd set of straps with a low anchor point (for head
to canopy interference) and the standard straps to keep from
submerging (family jewels to 5th strap interference).

Steve





On Thu, 09 Dec 2004 15:34:37 GMT, "Bill Daniels"
wrote:


"Marian Aldenhövel" wrote in message
...
Hi,

Your head is trying to stay where in one postion spatially, so the
result is a force against the canopy equal to the mass of your
head times the G forces.

Minus the force your neck exerts on your head, right? Which brings
us back to restraining systems.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de
"Flying an An-2 is like making love to a fat lady who's had too much to
drink:
there's a lot to work with, it's unresponsive, you're never quite sure
when
you're there, and it's big-time ugly."

Many Eastern European gliders have toe straps for the rudder pedals which do
a good job of keeping your shins from banging the underside of the
instrument panel. The seat belt does a great job of keeping your butt in
the seat. The problem is with the shoulder straps.

Since pilots sit reclining, shoulder straps are usually angled 45 degrees to
the longitudinal axis so they are only effective in preventing the upper
torso from bending up and forward at the hip joint in a crash. They are
much less effective in preventing the upper torso, neck and head from moving
vertically in turbulence.

What if the shoulder belts crossed over the chest like bandoleers and
attached to the seat belt anchors somewhat like double automotive shoulder
straps? That seems like it would secure the upper body well but I don't
know how a quick release would work.

The idea of shoulder restraints as part of the canopy frame would work great
with front and rear hinging canopies. I can't see it working with side
hinging canopies.

Thinking about this has made me realize that what I really fear about
turbulence is a head or neck injury. I'm not really concerned about an
upset since I know I can fly out of it safely. Getting knocked out by a
blow to the head is a real concern for me.

Knowing for certain that my head couldn't touch any part of the glider in
severe turbulence would be a real comfort.

Bill Daniels



--

------------+
Mark J. Boyd

"Steve B" wrote in message
...
I believe that the shoulder restraints are recommended to be anchored
no more than 5 degrees below the shoulder and 30 degrees above the
shoulder in a vehicle IIRC.

In a glider I would think that the reclined position would change the
dynamics of the restraint. Because of the reclined position I would
think that there would be less of a tendency to compress the spine
when the shoulder straps are under a load. Is the 5th strap and
submerging the issue?

Would a low anchor point help with the upward motion of the pilot? How
would a low anchor point respond with a reclined seating position in a
crash?

Sounds like keeping your head intact is a primary concern and spine is
secondary?

So I am thinking 2nd set of straps with a low anchor point (for head
to canopy interference) and the standard straps to keep from
submerging (family jewels to 5th strap interference).

Steve

snip some stuff

Okay, how about this:
Below the adjusters on each of the shoulder straps, sew an extra strap.
They should be long enough to go over your shoulders and Y together
somewhere in the vicinity of the small of your back.
A single strap continues down from there, through a slot in the seatpan, to
a low anchor point. It continues through the rear low anchor point to a
front low anchor point, where it becomes the crotch strap.
Now tightening the crotch strap will also pull down on your shoulders. The
low anchor point shouldn't compress your spine, because the rear low anchor
point should be in front of your shoulders.
Because the additional straps pull your shoulders down and forward, you
can't slide up and back along the normal shoulder straps to bump your head.
Because it's adjustable, it should fit more than one pilot. There's extra
strap, but the same number of adjusters, so it shouldn't be too expensive.

Obviously, a similar scheme could be used with two straps under the seat pan
in a 6-point harness arrangement.

Tim Ward

Bob Korves wrote:
If you have your head touching the canopy it cannot accelerate into the
canopy and hurt you.
-Bob

"Eric Greenwell" wrote in message
...

Bill Daniels wrote:


"Eric Greenwell" wrote in message

A "work around" I use is to press my body up against the belts. This
tends to reduce the "overshooting" that occurs when you are thrown
against the belts by negative G's, and reduces or eliminates the impact
with the canopy.

So, what about the idea of a pair of short, say 8", padded arms that

rotate

down over each shoulder and latch in place? That would prevent the

upper

body from rising and the head from snapping sideways. The latches would
release and the arms spring back when the canopy was opened.

Perhaps fixed arms could be on the canopy frame, so they would rise with
the canopy without any complications.

Another possibility would be a modified or removed seat back that would
give you more distance from your head to the canopy.

Any of these things would need careful design to ensure they don't make
other situations, like a crash, much worse.

Or maybe it's time for a different glider with a larger cockpit, or more
flexible wings!

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA



Not true about not hurting if your head can't move.

With my chute and 1/2" of dyna-foam behind me, my head is in contact with the
hoop of my Std Cirrus on launch. To stop banging against the canopy I tend to
push my head back against the frame in turbulence. Despite not being able to
move much the vibrations and variations in force still give me a nice clearly
marked bruise on the crown. The price we pay for being 186cm. I wonder about the
tall guys though.

For what it is worth, and for those who have not had the privilege of flying
one, the Cirrus has wings like a steel truss, very little flex so you notice any
turbulence. Makes finding thermals easy though...

At 18:30 09 December 2004, Mark James Boyd wrote:
Here's a wierd idea:

Get longer wings. If the wings hit an updraft, they
will
go up, and flex, but the fuselage won't go up right
away,
kind of a 'shock absorber.' Then the wings will reflex,
giving extra thrust, and dissipating the G's. A few
oscillations
later and you'll feel real queasy, but you'll have
more glide
and less G's. Better all around, right?

OK, a bit off thread, but has anyone modeled this (dynamic)
interaction? Sure sure, we know about best glide,
but what
about the effect of long wings flapping like a seagull
in turbulence?

This does NOT seem to be the same kind of thing Gary
Osaba does in the Sparrowhawk or Carbon Dragon (with
super stiff
wings), but it seems related...

Any long-wingers care to comment?

I can't quote chapter and verse from memory but there
was quite a bit of discussion in the late 70s that
floppy wings (as in the ASW 20 and 17) could gain energy
in wing up flex from positive g gusts and then release
it in the down flex as lift/thrust. I always wondered
why it wasn't also discussed whether they would lose
a similar amount of energy in negative g gusts.

John Galloway