Looking at the Technical Soaring paper from 2009
linked by Cumulus-Soaring did everyone notice the line:
"It does appear that the usefulness of safety
cushions made out of these materials can be
significantly compromised at temperatures well over 20C."
What would be the equilibrium temperature of a
piece of foam next to a human body?
Seems the best crash worthy foams may reduce the
maximum G load by about 15% (from reading Tony
Segal's articles). Probably worth having but if
you crash just a little harder you are still going to have problems.
Is there any evidence of better outcomes
with/without the foam? There ought to be but
without actual statistical evidence (should be
available as the real accident rate of gliders is grotesque) we can't say much.
Noel is right. Learn to fly properly and don't
crash. Gliders are dangerous and you are at the sharp end.
NACA/NASA data on forced landings has the
probability of death injury vs angle you hit the
ground (search for it - I don't have the URL at
hand) and the 61 knot stall speed limitation is
based on WW2 data from forced landings which show a knee in the curve at 61
knots. Don't forget much of this would be from
single engined fighters with a large heavy engine
in front of the pilot. In gliders you are in place of the engine.
Mike
At 08:44 PM 12/17/2017, you wrote:
>>There's a heap of stuff online if you look. Search for "BGA confor
dynafoam back injury".
I have looked extensively. I am aware of no
study that investigates, let alone concludes,
whether having 'energy absorbing" cushions will
result in improved outcomes in a glider crash.
In fact one of the major ones comparing dynafoam
and confor explicitly warns not to over estimate
the significance of their study.
On Sun, Dec 17, 2017 at 9:08 PM, Matthew Scutter
<<mailto:[email protected]>[email protected]> wrote:
Not all 'memory foams' are alike, in fact I am
extremely dubious my memory foam mattress is any
different to a regular foam mattress in any regard other than marketing.
I think it's pretty unlikely the Aldi mattress
has the viscoelastic properties desirable for increasing crashworthiness.
<https://www.cumulus-soaring.com/misc/e-a-r/CONFOR-Foam-Technical-Paper-Comparison-Of-The-Characteristics-Of-Energy-Absorbing-Foams-For-Use-In-Safety-Cushions-In-Glider-Cockpit.pdf>https://www.cumulus-soaring.com/misc/e-a-r/CONFOR-Foam-Technical-Paper-Comparison-Of-The-Characteristics-Of-Energy-Absorbing-Foams-For-Use-In-Safety-Cushions-In-Glider-Cockpit.pdf
CONFOR was measured to provide the best
performance of a number of crash foams so that's
what I have. I think cutting costs by going with
totally unknown foams is probably not fulfilling
the intent of the MOSP directive even if it
fulfills the lettering. It's a sore point for me
though as I once hurt my back in a hard outlanding accident.
The BGA has a nice overview which read a bit
handwavey but has some very good citations backing it up at the bottom.
<https://members.gliding.co.uk/wp-content/uploads/sites/3/2015/04/Safety-Foam-ed2.pdf>https://members.gliding.co.uk/wp-content/uploads/sites/3/2015/04/Safety-Foam-ed2.pdf
On Sat, Dec 16, 2017 at 9:36 AM, Greg Wilson
<<mailto:[email protected]>[email protected]> wrote:
Aldi have queen bed size piece of memory foam 50
mm thick on special for $150 today.
No idea if itâs dense enough for glider seats but could be a real bargain.
Merry Xmas!
Greg Wilson
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