Update 3/30/2015 – Machine Shop Troubles

Hi all,

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!

Stress Simulation - Injector

Stress Simulation – Injector

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? lprdrocketry@gmail.com).

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

3/30/2015

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Update 3/15/2015 – Spring Break? What Break?

Hi all!

Brief update this week, due to it being spring break and all. We made some minor design changes after finding out the professional research shop here would not be able to braze copper to aluminum for us. Instead, we took their advice and replaced that design feature with some additional O-rings to seal against pressure. Luckily, that changed our designs very little and we don’t need to scrap any work. Below are some pictures of work in progress from the machine shop.

Injector almost finished! Just needs threads in the top for 1/4 NPT thread. This bottom view shows the small size of the injector holes for oxidizer. Precisely drilling those holes was quite the hassle.

Almost finished injector

Almost finished injector

Injector bottom, NPT threads, and tiny injection holes for O2 simulant

Injector bottom, NPT threads, and tiny injection holes for O2 simulant


 

The coolant jacket is finished! Though the piece will be under the least stress during tests, it’s yet one of the most critical for keeping the engine cooled against the incredible temperatures inside. This is one of the pieces with an additional O-ring groove.

Finished Coolant Jacket

Finished Coolant Jacket

Coolant in port with garden hose thread

Coolant in port with garden hose thread

O-ring groove to seal with  chamber wall

O-ring groove to seal with chamber wall


 

And here’s the exciting piece – in about 1/4 its eventual glory – the combustion chamber!

Unfinished chamber wall

Unfinished chamber wall


 

The oxygen reservoir – the piece that sits atop the injector and contains the in port for oxidizer. This piece also has an additional O-ring groove to seal between itself and the injector.

Very unfinished xygen resevoir

Very unfinished xygen resevoir

O-ring groove to seal with the injector

O-ring groove to seal with the injector

Interior of oxygen resevoir

Interior of oxygen resevoir


 

And here: behold the tower of parts. Obviously, everything is a little unfinished and doesn’t quite fit together properly yet, but you can get a general sense for how everything might look when it slides together nicely and the excess metal is chopped.

Unfinished parts stacked in assembly order

Unfinished parts stacked in assembly order


 

By the end of this week, everything will be complete machining-wise and we hope to pressure test on the 28th.

Full Stand Assembly

 

There are still some kinks to work out in the electronics/control (the electric ball valves we ordered came with exactly zero instructions), but we should be ready engineering-wise! The critical path is now getting through bureaucracy and sourcing gas canisters through the University.

– David Deng

3/15/2015

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Update 3/8/2015 – Money Equals Freedom – Kevin O’Leary

Hi all!

Good news this week, TeslaWorks has funded the cold-testing part of our project for $3250 ($3300 if you include the funding for 3D printing), everything we asked for, so I suppose we could call that a success. We would of course like to thank TeslaWorks dearly for their support (and the fact they’re letting us operate under their umbrella). TeslaWorks does many other incredible projects worth checking out, so go take a look!

The funding is on stipulation that it’s only for a pressure test piece unless/until the University approves hot firing, so it covers all raw metal stock, fasteners, electronics, most piping and valves, but not oxygen gas or the corresponding tanks and regulators. If anyone wants to take a look, this is what it entails. Along with the funding itself, this means we can purchase materials through the University instead of contacting industrial suppliers ourselves, so this funding saves us a ton of non-monetary headache as well.

Of course, we will be following both the letter and the spirit of the University’s policies so long as we are affiliated with it. “A good reputation is worth more than money” – Publilius Syrus

This week’s update is short and sweet, as we wind down just a little bit to let the team members focus on their midterms and relax a little bit into spring break.

-David Deng


 

Engineering Subteam Spotlight: Propellant

The Propellant Team has finished both the design and sourcing of parts for the feed systems.  All of the parts from McMaster Carr have arrived leaving the electric ball valve, solenoid valve, and nitrogen tanks and regulators as the only remaining items. Our wonderful team assembled the various components in our possession as seen below.

If only everyone to smiled so brightly when working...

If only everyone to smiled so brightly when working…

Busy busy!

Busy busy!

The large black steel pipe will serve as the liquid reservoir complete with a drain below and an over-pressure relief valve at the top. To the right of this are various connectors and an assortment of check, purge, and blowout valves in order to keep the feed system operating safely. Once the remaining items arrive, the entire system will be assembled and hydrostatic testing can commence!

-Mike Siirila

3/8/2015

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Update 3/1/2015 – Easy as ABS, 1-2-3, That’s How Easy Parts Can Be!

Hi all!

Look! Cool stuff! That is all. Anyone see any differences from our CAD images?

3D Printed Injector Model

3D Printed Injector Model

3D models unassembled

Disassembled 3D Printed Models


3D assembly

Assembled 3D Printed Engine Model

In all seriousness, we’re super grateful to TeslaWorks for letting us us get 3D printed scale models through their student group. The quarter scale (by length) pieces you see took three hours in the printer and four hours in the bath to remove support material, and took just under one cubic inch. We’re also printing a scaled up version (1.8x by length compared to these pieces) because for some reason, everyone keeps telling me that “bigger is better.” How very cheeky of them.

On an unrelated note: our order from McMaster-Carr came in! It’s like Christmas all over again.

Parts and Materials!

Parts and Materials!


Engineering Subteam Spotlight: Engine

This week, we’ve been busy in the machine shop (as you can see)

Riley on the Lathe with the Oxygen Resevoir

Riley on the Lathe with the Oxygen Resevoir

Elliot machining

Elliot Adjusting a Mill

 

The simplest piece (nozzle plug) is finished. Looks a bit like the tin man’s hat from The Wizard of Oz, if you ask me.

Finished Nozzle Plug

Pictured: Tin Man from Wizard of Oz

Our Nozzle Plug.

Our Nozzle Plug – Public Domain Image from Library of Congress, Accessed through Wikimedia Commons

And we’re almost done with the aluminum version of our injector. Our supplier for copper was out of stock until recently, but they’ve shipped our order now). We just have two holes to thread with ¼ NPT and ⅛ NPT respectively, two 0.6mm holes to drill (below are the micro-bits for that size), and four holes for bolts.

With an itty bitty waist and a... oh. Yeah, it's itty bitty all the way down.

With an itty bitty waist and a… oh. Yeah, it’s itty bitty all the way down.

Elliott and Ian have been hard at work, and it’s really paying off!

Unfinished Injector 03012015

Unfinished Injector

Pictured: Elliott. Working Very, Very Hard.

Pictured: Elliott. Working Very, Very Hard.


On the business side of of the project, we’ve also been busy lobbying TeslaWorks for money, exploring other potential funding sources – if anyone has ideas or contacts, please let us know ;). We also created an informational poster/brochure for an event we were invited to attend, but in the end weren’t able to participate. In any case, we still have a beautiful poster of smiling faces to display, courtesy of our very own Christian Yonkoski.

We are LPRD

We are LPRD

-David Deng

3/1/2015


PS – Congratulations to SpaceX on their successful launch tonight of the satellites ABS 3A and Eutelsat 115 West B to a supersyncronous transfer orbit (meaning they’re on their way to an orbit above those of geosyncronous satellites – those that orbit at the same rate the earth turns). As you can probably tell, we at LPRD Rocketry are big fans of SpaceX and their accomplishments in rocketry, and we look forward to seeing what Elon Musk can accomplish over the next couple years. Here is the video of the launch.

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