ET foam

Shuttle piggybacking on an external foam insulated tank is conceptually
wrong, since foam always have tendency to peel during lift-off. To find
a reason why foam is shedding from the external tank, NASA has to
consider that tank is a FLEXIBLE body filed
with liquid. During liftoff, tank deforms in all three dimensions.
Deformed tank skin cracks foam and loosens it. Shivering of a tank
skin, tank vibrations, trajectory correction jolts and small packets of
high-low air pressure created around a tank produce a foam shake-off
("bathing birds") effect.

Highly-tear-heat-resistant and FLEXIBLE coating applied over foam will
prevent its shedding.

On Thu, 6 Oct 2005 08:33:37 -0500, wrote
(in article .com):

Shuttle piggybacking on an external foam insulated tank is conceptually
wrong, since foam always have tendency to peel during lift-off. To find
a reason why foam is shedding from the external tank, NASA has to
consider that tank is a FLEXIBLE body filed
with liquid. During liftoff, tank deforms in all three dimensions.
Deformed tank skin cracks foam and loosens it. Shivering of a tank
skin, tank vibrations, trajectory correction jolts and small packets of
high-low air pressure created around a tank produce a foam shake-off
("bathing birds") effect.

Highly-tear-heat-resistant and FLEXIBLE coating applied over foam will
prevent its shedding.


Well thank God after nearly 35 years of development and 25 years of
flight operations, some anonymous genius from Usenet is around to help
them out. I'm sure vibrations, thermal environment, acoustics and
material properties never once occurred to the ET designers. So
thanks!

--
"Fame may be fleeting but obscurity is forever." ~Anonymous
"I believe as little as possible and know as much as I can."
~Todd Stuart Phillips
www.angryherb.net

Herb Schaltegger wrote:

Well thank God after nearly 35 years of development and 25 years of
flight operations, some anonymous genius from Usenet is around to help
them out. I'm sure vibrations, thermal environment, acoustics and
material properties never once occurred to the ET designers. So
thanks!

You forgot to mention that the high-speed, highly variable airflows
around the ET during launch would be kind to the "FLEXIBLE coating
applied over foam." See, it deforms the way you *want* it to if any
foam beneath it shifts, but never the way you *don't* want it to, like
say ripping to shreds within a minute or two. It's great stuff...
really.

"Monte Davis" wrote in message
...
Herb Schaltegger wrote:

Well thank God after nearly 35 years of development and 25 years of
flight operations, some anonymous genius from Usenet is around to help
them out. I'm sure vibrations, thermal environment, acoustics and
material properties never once occurred to the ET designers. So
thanks!

You forgot to mention that the high-speed, highly variable airflows
around the ET during launch would be kind to the "FLEXIBLE coating
applied over foam." See, it deforms the way you *want* it to if any
foam beneath it shifts, but never the way you *don't* want it to, like
say ripping to shreds within a minute or two. It's great stuff...
really.

I hope they're using Great Stuff Pro (http://greatstuff.dow.com/pro/) on the
ET, not the cheap stuff you get at the local hardware.



Jeff
--
Remove icky phrase from email address to get a valid address.

in article , Herb
Schaltegger at LID wrote on 10/6/05
6:47 AM:

On Thu, 6 Oct 2005 08:33:37 -0500, wrote
(in article .com):

Shuttle piggybacking on an external foam insulated tank is conceptually
wrong, since foam always have tendency to peel during lift-off. To find
a reason why foam is shedding from the external tank, NASA has to
consider that tank is a FLEXIBLE body filed
with liquid. During liftoff, tank deforms in all three dimensions.
Deformed tank skin cracks foam and loosens it. Shivering of a tank
skin, tank vibrations, trajectory correction jolts and small packets of
high-low air pressure created around a tank produce a foam shake-off
("bathing birds") effect.

Highly-tear-heat-resistant and FLEXIBLE coating applied over foam will
prevent its shedding.

Well thank God after nearly 35 years of development and 25 years of
flight operations, some anonymous genius from Usenet is around to help
them out. I'm sure vibrations, thermal environment, acoustics and
material properties never once occurred to the ET designers. So
thanks!

You sound overjoyed, but reading between the lines I suspect sarcasm. How
will we ever progress if we aren't open to all suggestions? ;-)

George Evans

The 'O rings', the 'ET', and the 'tiles' are all external features of
the Space Shuttle.

Let's get rid of them and build a true SSTO HTOL. It is not an
impossible dream, it is getting rid of known Space Shuttle problems.


tomcat