[SS-VehDev] Re: composite short stack/instrumentation section

[william colburn]

Yes, back from my convention. Interesting to see what
biologic processes they are even now doing in orbit,
and only able to do in orbit.

--- Lakestake Rocketry <lakestake at gmail.com> wrote:

> 

> 
> > Are you looking at using a metal liner as the
> mandrel and leaving it in
> > the
> > lay-up? This would help with leaks and possible
> even temperature (if it's
> > made of something like titanium).

Interesting, but if we made a liner we would probably
just use the liner of proper thickness for the motor
case. The comment about weight when using a liner plus
the composite is appropriate, we are extremely weight
limited. Bot the vendors we are looking at offer
impermeable tubing. The hand layup would also be lined
with an epdm liner (correct Rich?) very traditional in
the composite motor arena. Porosity goes way with
additional thermal protection.
> 
> Are you vacuum-bagging the lay-up?
> 
> 
> Yes, vacuum bagging was the method proposed.

The shrink-wrap method works well for hand-layups.
Can't be used at high temperatures, but it works well
for an initial room temperature cure, which is then
followed by th manufacturers recommended cure cyle.
> For the amount of fiber we'll need for this project
> we should consider a
> different source. I think that Roman may have good
> suggestions along
> these lines. If you (Colin) or any other team member
> has a thought please
> pipe up!

Remember, we have a composite source as a sponsor...


> > Flat section or cylindrical? They will be very
> different to
> > manufacture. If I were going to test it then I
> would lay-up a section that
> > is cylindrical this will give you a more realistic
> answer as to wether or
> > not the lay-up is suitable.

I second this opinion. The part for testing must be
made in exactly the same manner as the finished
product. A section of a tube is what se need to test.
The "tube" can be 2 inches long, just so long as it
has exactly the same process involved in creating it
as in the final tubing.

> > Another options is to just lay up the entire part
> and test it for
> > strength. If it's not the required strength then
> you could always just add
> > a few more layers to it.

We intend to hydrotest a 40 inch section.