For our rocket work we bought an off-the-shelf tube (solid rocket motor)
with o-ring grooves already in it from Loki Research. Also got a custom
nozzle from them. Then we made our own injector bulkhead for the forward
end. No need to machine any interior o-ring grooves.
On Fri, Oct 15, 2021 at 12:17 PM roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
Hi Jack, O-ring grooves are challenging particularly with
rudimentary machining skills. Perhaps another sealing method could be
looked at especially when weight isn't an issue being a boilerplate ground
test article. Maybe a crush gaskets at the motor ends using external
tension rods to bolt the end bulkheads together. This is a common
method for just such battleship designs.
If the ends aren't going to get too hot,<400F, then PTFE/Teflon crush
gaskets otherwise copper/asbestos crush gaskets are good to 900F.
And don't get discouraged, take a break then come back with a
vengeance and build the thing but definitely don't compromise safety
because of "launch fever".
or testitus. These days phtography idsd so seay so document everything to
learn from every millisecond of test data.
Good luck,
Ken
On Fri, Oct 15, 2021 at 8:17 AM Jack Hanna <jackhannaofficial@xxxxxxxxx>
wrote:
Hello!
I've been having problems, mainly with machining and in general when
trying to make a hybrid nitrous-paraffin ground only rocket engine it's
been quite rough, and the lack of a mentor and machining knowledge has led
to about three weeks worth of work just being a couple of tubes. I have
been trying to cut o-ring grooves for probably about 6 hours, and have just
completely failed. I technically have a couple of grooves in the outer
tube, but I worry that if I purchase lower profile o-rings that it still
won't be sufficient sealant and it will just be a glorified bomb when I go
to ground test it. That's the other issue, the last chance I really have to
test it is on october 30th, and that deadline has me kind of cramming, and
the absolute last thing I want to do is to rush it, and make a bomb instead
of a rocket engine. I've also been bad and skimped a little on the math and
other parts for time, and my plan really just boils down to shoving nitrous
through a tube with paraffin, standing very far away, and hoping for the
best.
Is it worth it to try and continue with this subpar design, or should I
scrap it and pick it up later when I have more time / experience?
I really want to do this, but I also want to know if it's going to
actually be severely dangerous or just have no chance at success. How much
can you bodge a rocket engine and still have it work ok?
Thanks.
- Jack