If I had to do it today I would do what I currently do: composite entrance,
graphite throat, zirconia coated titanium exit.
However, as I've moved to 6" and now 9" motors the cost of titanium parts
is getting to be an issue (the nozzle exit is typically reusable if you can
find the spent stage) so I am looking to move to carbon / phenolic for the
entrance and exit.
For environments where the graphite might fail (oxidation, typically) I
would add polyethylene BLC to protect the wall.
Bill
On Tuesday, December 1, 2015, Paul Breed <paul@xxxxxxxxxx> wrote:
If one was going to build a solid vacuum stage,
has anyone on this list built a flight weight high expansion ratio solid
motor?
Clearly just turning a steel or graphite solid expansion cone is either
low expansion ratio or not flight weight.
If its a simple long tubular solid the expansion cone is going to have to
be bigger than the case diameter....
Looking at professional vacuum stage solids one sees carbon carbon
expansion bells and fuel geometries that aren't the simple tubular solids
that typify the amateur solid...
Like:
http://104.131.251.97/spacerockets/wp-content/uploads/sites/17/2015/08/9166357_orig.jpg
)
