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Re: Subject: seat foam

Subject: Re: Subject: seat foam
From: Fred Fillinger <fillinger@ameritech.net>
Date: Thu, 24 May 2001 10:08:35
Is there a technical citation for any of this?  Regulations in the US
governing seat construction of even airliners have no such
consideration, and those regs are pegged to G forces much greater than
mere hard landings.  The slower energy absorption of temperfoam et.
al. is superior, as the usual foam of typical thickness can bottom out
I believe is the phenomenon.  But G-doubling, rebound spinal damage
even in a hard landing?

It appears that 1" of temperfoam is inadequate.  The second stiffest
1" foam I have compresses almost completely (at room temp), allowing
for little further absorption and compromised comfort.  Usual practise
if nor mfr recommendation, is 3", varying densities...?

Regards,
Fred F., A063

> Forwarded from the bounce bin. Message is from
> mks <mks@darcy.gwis.com>
> *****************************************************
> Here is a short technical explanation why energy absorbing foams are a
> must have in an airplane.
> 
> Soft spongy foam in a hard landing has the unfortunate property that
> it slows down the rate of descent of your body while the AC does a
> hard bounce and comes back in the opposite direction - thus giving
> your back a very hard whack.
> 
> Energy absorbing foams are very dense and compresses slowly.
> Consequently, the foam absorbs energy during the hard landing and
> your body does not get the doubling of force as in the above case
> because the body and AC move together.
> 
> >From a comfort perspective, while dense foam is not as nice
> initially as the soft stuff, I find it provides much better support
> and comfort for long flights.
> 
> I am not familiar with the foams you mention. I use confor foam.
> As long as you get an energy absorbing foam you should be fine.
> I personally use about one inch thickness. The only weakness with
> the confor foam is when it gets cold (freezing) it gets stiff as
> a board. Warm it up and it regains compliance. Dont flex it while
> it is cold or it will break.
> 
> Hope that helps,
> 
> M


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