In article ,
says...

On 2018-06-14 05:22, Jeff Findley wrote:

Innovation in terms of engineering, but not new technology.

OK, I understand your argument.

But just because carbon fibre has existed for some time does not
automatically "void" the "new technology" when it is used in new
applications such as cryo tanks or aircraft fuselage.


Carbon/fibreglass were originally just "fabric" that was cut to right
shape, layed up and resin applied to it and let it cure.

True, but that's essentially still the state of the art today.
Composite layup machines have been around for decades. A guy I used to
work with wrote the layup software for the Cincinnati Milacron machines
back in the 1980s. What they sell today evolved from those machines:

https://metal-cutting-
composites.fivesgroup.com/products/composites/fiber-placement-
systems/cincinnati-viper-fps.html

Wouldn't you agree that it is new technology to take the raw strands in
a large spool, and lay individual strands in a computer optimized
position/direction just after the strand has been impregentated with resin?

Nope, as I said, been done at least since the 1980s in an automated
fashion. Sure the tech keeps getting better allowing for bigger
structures, but it's an evolution of tech that's decades old.

This new tech allows totally new applications that were not possible
before with that same material.

Airbus for instance developped new tech to combine 2 existing materials:
glass fibre and aluminium (Glare which has layers of aluminium, layes of
glass fibtre composited together). You can view this as either a new
material, or just "engineering" of 2 existing materials.

Materials tech is always evolving. This is a tad different than carbon
fiber layup, so I'd count that as new, whenever it was first done. I'm
not a materials engineer, so I don't know when that would be for glass
fiber and aluminum.

Coming back to SpaceX, I am not sure if their building an all composite
cryo tank for BFR represents new tech or not. If they are using the same
techniques/equipment as Boeing uses for the 787 for instance, it woudn't
be "new technology". But it is also possible that they develop new way
to lay the fibre to make the tank. There is also the issue of the resin
and how it is cured which could potentially represent new tech
(especially if they do away with an autoclave or curing oven).

X-33 attempted to do just that. It failed due to the complex geometry.
BFR/BFS is sticking with traditional cylindrical tanks, which is a
proven geometry for carbon fiber composites. They're being pretty
conservative as far as their use of carbon fiber goes, IMHO.

From what I've read, they'll be sticking with traditional techniques to
minimize development risks. I fully expect them to cure it in an
autoclave.

Orbital ATK, or whatever it's called now, is doing much the same with
their OmegA SRB segments. Again, this is a proven technology used by
Orbital ATK for many programs. NASA had a composite wound SRB program
many decades ago. It was canceled due to cost overruns, but that
technology is in use today and proposed for SRB upgrades for SLS, but
that wouldn't fly for maybe 10+ years given the pace of SLS Block 1
development.

http://www.spaceflightinsider.com/or...e-on-one-with-
atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-
system/

Jeff
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