Welcome back to the post after Spring Break! I apologize for the lateness of this post, but it’s been a hectic week. Unfortunately, we forgot to take photos/weren’t able to take photos during our events this week, so there’s no picture evidence except this boring steel frame. We promise many many pictures next week!
Luckily, we did run a few stress test simulations in Inventor, so here’s a pretty picture from that. Nothing greater than 8-ish MPa, so that means our safety margins are all nice and high, just like planned for this first engine!
Biggest news is we now know where we’ll be doing hot fire tests, thanks to Orbital ATK. We went and made a technical presentation, assured everyone we partially knew what we were doing, and then were treated to a delightful tour of the place where some of the coolest armaments are tested. Perhaps the University’s safety committee will be swayed when we tell them we’ll be doing tests from a bunker protected by a couple feet of concrete, behind a blast plate, behind the blast plate on our test stand. I’m at least marginally hopeful.
As prep for the presentation and tour, we spend quite a bit of time this week writing up test procedures. Basically, operating even a simple pressure driven engine like ours is pretty complex, so we’ve got a timeline written out to three hours before ignition. In the end, it’ll be a four man team working to operate everything.
Meanwhile, we also ran into some trouble with machine shop access. Now that coursework is ramping up, the Mechanical Engineering Student Shop has kicked out TeslaWorks (the student group we operate under) from the machine shop so they can dedicate space and time to the students who require the shop for coursework. Unfortunately, we’ve also been alerted that next year we’re unlikely to have access to the shop either, because they’re moving locations within the university and will be highly constrained on space. Soooooo, we’re trying to figure out this relatively large roadblock. We’re talking to some friends who have friends who might be able to help us out, but if you could help or know anyone who might be able to, we’d be very, very grateful (email us? firstname.lastname@example.org).
This last weekend, we also partially assembled our test stand and got a good look at how everything would fit together. There are a few geometry issues to address, but everything should be a relatively quick fix and the parts have already been ordered and should be on their way!
We also tested out our ball valves for the first time this week, and they are far, far, far slower than we expected (more than a minute to fully open), and there’s no way to hold them in a partially open position. This means we may need to purchase new ball valves or modify our procedure for hot fires, but they should still suffice for pressure tests.
Finally, we’re hoping to have a pressure test relatively soon. We’re still a uncertain on when exactly the time will be, as it depends on machining and TeslaWorks paperwork, but we’re hopeful we can have a test either this Saturday or next Saturday. If you’re interested, fill out the form below and we can keep you posted!
– David Deng