We also need to figure out how to best plumb the lines from the main LOX valve to the LOX dome including fittings to purge this line as well. As you can see in the photo below the stainless steel braided LOX hose would need to make a tight radius bend to connect with the LOX dome flare fitting. Www.anplumbing.com has a great selection of aluminum Earl's AN fittings and has a 90 degree adapter fitting we may be able to use. The alternative is to route the line outside the airframe for the static test.
Paul Breed has gratiously donated new pressure transducers to us. These transducers have a 0-5VDC output and integrate better to the elctronics. We will be monitoring via telemetry pressure in the helium tank, LOX tank, kerosene tank and the combustion chamber.We also changed out a valve on the SSPS to allow us to pre-fill the "dome-dump" accumulator more easily.
This upcoming week is spring break, so I'm not too sure how many students are planning on being in town. Once the motor is fully plumbed we can begin our final testing.
--- Carl
7 comments:
I've linked your blog on ours.
Y'all seem to be making great progress. We're just about to order a bunch of plumbing from Swagelok so your post is well timed ;)
Have you used aluminum fittings and pipes before for LOX service? We had a big argument about it up here as an engineer from Praxair told us that he's seen aluminum LOX tanks under pressure blow up rather spontaneously.
It's interesting to note that our airframes and overall vehicle layouts are very similar. Good luck with the rest of your build!
ubya,
At our operating pressures (no where in our system do we exceed 500 psi) aluminum is fine. Beware...Swagelok is very expensive. The aluminum AN fittings are lighter and a about 1/4 of the cost of stainless steel fittings. I wouldn't stress out about weight so much on a studnt rocket project, but it is easy to amass 15 to 20 lbs of fittings on a project like yours.
Our tanks are stainless steel tanks. I would not have any reservations about using aluminum tanks at these pressures provided we did adequate hoop stress caalculations and have an adequate pressure relief valve on the tank in the event the LOX boils off too fast. I don't buy your Praxair reps comments that aluminum tanks blow up. Most all rocket tanks are aluminum (Atlas V, Delta IV, Space Shuttle ET, etc.)
--- Carl
what's going on here!? Still on for static fire 26th?
Carl: Can you pass on info regarding the electronics package and the telemetry you are using for pressure etc. Dan
Dan,
Sorry for the delay. We are using a Netburner computer to collect and digitize the signals from our pressure transducers. They have a $99 development kit. This data is then sent wireless via a Maxstream 1 watt radio modem.
--- Carl
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