seat belts and restraints

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."

Speaking as someone who has never flown is severe rotor I would be somewhat
worried about the structural integraty of the glider if you are being thrown
about so severely. How rough is rough?
Since gliders tend to be more strongly constructed that light aircraft I would
also be worried for the poor pilot in the tug.

"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

"OscarCVox" wrote in message
...
Speaking as someone who has never flown is severe rotor I would be
somewhat
worried about the structural integraty of the glider if you are being
thrown
about so severely. How rough is rough?
Since gliders tend to be more strongly constructed that light aircraft I
would
also be worried for the poor pilot in the tug.

As long as the aircraft is flown below the Va (Maneuvering) and Vb
(Turbulence Penetration)airspeeds it should be able to withstand a sharp
edged gust load of, I think, 30 FPS. (32FPS?) There may be no practical
distinction between Va and Vb in this case since the controls are likely to
be continuously hitting the stops in this kind of turbulence as the pilot
tries to maintain control.

There is no doubt that wave rotors (and thunderstorms) can produce gusts
that exceed that value since there is a history of severe damage to
airplanes and gliders.

The key is keeping the airspeed well below the Va - Vb speeds particularly
when flying downwind since the rotor is stationary with respect to the
terrain. The glider will traverse the gust edges faster so the "bang" is
sharper. If an unlucky pilot encounters a series of gusts at an airspeed
that produces a frequency that equals the natural resonance of an aircraft
structure, damage may result at a lower airspeed.

In these incidents there is always the question of whether the pilot was
incapacitated before or after a catastrophic structural failure. My
experience suggests that getting knocked out first is a real possibility.

Slightly off topic now. There used to be a slickly produced poster using
FAA-like language on the wall of the airplane FBO at Boulder, CO. It
purported to describe light, moderate and severe turbulence. In fact, it
was a practical joke on visiting flatland pilots who were encountering
mountain turbulence for the first time.

It described "light" turbulence as causing "occasional negative G".
"Moderate" turbulence was described as causing "occasional loss of control
of the aircraft". "Severe" turbulence was described as "total loss of
control for extended periods of time." Locals tried to keep a straight
face as wide-eyed flatlanders read the poster. Glider pilots didn't laugh.

Bill Daniels

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...

"OscarCVox" wrote in message
...
Speaking as someone who has never flown is severe rotor I would be
somewhat
worried about the structural integraty of the glider if you are being
thrown
about so severely. How rough is rough?
Since gliders tend to be more strongly constructed that light aircraft I
would
also be worried for the poor pilot in the tug.

Rough can be bloody rough. I have ...

Been rolled past the vertical in spite of full opposite controls,

had the ASI fluctuating from 40kph to 120kph almost instantly,

experienced vibrations like driving on a corrugated dirt road.

And, as Bill has intimated had big 'pushes' both positive and negative. At
least +- 2G. Some people have had worse.

I have never turned back or landed because rotor but I have been airborne
whilst older and wiser pilots ( not necessarily less brave ) have.

Rotor is sometimes 'the price you have to pay' for the magic of the wave.

Ian

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

Back around 1992 or so, I saw an old, odd looking Cezzna
at a local airport. It was either an old 182 or an
even older 210 with the strutted wings. (This was
at Triple W airport on the south side of Raleigh, North
Carolina, USA)

The very odd thing I noticed was a small, round pressure
gauge mounted near the lower end of the each wing strut.
Then, I noticed some type of gas damper mechanism
between the lower wing strut attachment and the fuselage.

What the heck?

I was told this STC mod also put 'hinges' of some type
at the wing roots and allowed the wings to flex in
turbulence, to give a better ride. The person said
it looked VERY ODD when the wings stalled and flexed
upward (or the fuselage fell downwards.)

Ray Lovinggood
Carrboro, North Carolina, USA