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UCSD students test fire 3D-printed metal rocket engine

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October 12, 2013

The Tri-D engine test firing

The Tri-D engine test firing

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Like something out of a Robert Heinlein novel, students at the University of California, San Diego (UCSD) have built a metal rocket engine using a technique previously confined to NASA. Earlier this month, the UCSD chapter of the Students for the Exploration and Development of Space (SEDS) at the Jacobs School of Engineering conducted a hot fire test for a 3D-printed metal rocket engine at the Friends of Amateur Rocketry launch site in California’s Mojave Desert. This is the first such test of a printed liquid-fueled, metal rocket engine by any university in the world and the first designed and printed outside of NASA.

The Tri-D rocket engine, as it’s called, was designed and built with the cooperation of NASA’s Marshall Space Flight Center as part of an effort to explore the feasibility of printed rocket components. For purposes of the exercise, it was designed to power the third stage of a Nanosat launcher, that is, one capable of launching satellites that weigh less than 1.33 kg (2.93 lb).

Tri-D is only about 7 in (17.7 cm) long and weighs about 10 lb (4.5 kg). Made of a chromium-cobalt alloy, it burns kerosene and liquid oxygen and produces about 200 lb (90.7 kg) of thrust. The students’ main contribution was design of the injector plate, which is a key component used to inject fuel into the combustion chamber. In this case, the injector has a Fuel-Oxidizer-Oxidizer-Fuel inlet arrangement with two outer fuel orifices converging with two inner oxidizer orifices.

The rocket has a regenerative cooling jacket that extends to the nozzle to keep the engine cool while firing. It was designed to burn the fuel in the middle of the combustion chamber to keep as much heat as possible away from the chamber walls, while insulating them with a boundary layer of relatively cool gases.

The Tri-D engine cost only US$6,800 with NASA putting up US$5,000 and the students collected the balance with fundraisers, such as barbecue sales.

The engine was printed by GPI Prototype and Manufacturing Services using a technique called Direct Metal Laser Sintering (DMLS). In this 3D printing process, a powder of the chromium-cobalt alloy is spread in a thin layer by the printing machine. A computer-controlled laser then fuses the powder into a cross section of the engine component. The machine spreads a second layer of powder and the process repeats until the component is complete. The excess powder is then removed as are any temporary supports printed to hold the component together during printing, then it’s hardened, polished and assembled.

The advantages of 3D laser printing is that it’s much cheaper and faster with jobs normally taking weeks being completed in hours. Also, printing allows for more intricate designs for each piece and, therefore, fewer parts for the finished product. In addition, printed alloys have greater tensile strength than castings.

According to UCSD, the the tests at Mojave went without a hitch and the engine exhaust achieved supersonic velocity. "It was a resounding success and could be the next step in the development of cheaper propulsion systems and a commercializing of space," says SEDS President Deepak Atyam.

In addition to the successful test, the Tri-D design won the Student Prize award in the DIYRockets competition hosted by DIYRockets Inc.

The video below shows the test firing of the Tri-D rocket engine.

Source: UCSD

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About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy
11 Comments

Cool! But I still want a rocket printed in one piece.

Slowburn

That's fantastic.

Nicholas Mathews Hoover

Pretty cool, but also interesting to note that soon anyone with enough money will be able to launch anything from their own back yard, of it's been like this forever, but now the applications are so much more... real.

bullfrog84

incredible! thanks for the read....

billybob1851

Blink ...and technology takes a giant step.

Ron Jenkins

Very cool ,3D printing has so many possible ways to create new ,useful and less expensive things . It's just that sometimes they use it to make things that are more cost effective with conventional methods . " Like that ridiculous faux sandstone room ." Great to see the progress !

randomray

That video was too cool. I want one for my bicycle.

Dan Parker

How was it hardened?

Is the technology available as open source? Especially the "regenerative cooling jacket".

Did they pay F.A.R.?

How does the private sector benefit from this research?

Don Duncan

"students at the University of California, San Diego (UCSD) have built a metal rocket engine using a technique previously confined to NASA."

Well, ....no.

About 2-3 years ago Paul Breed, founder of "Unreasonable Rockets", a competitor in one of NASA's centennial challenges, designed and ordered a Hydrogen peroxide engine from a 3-d printing company that works in metals, and fired it successfully. IIRC, it cost him about $5,000 for the printing job.

Sine Arrow

Wunderbar, NOW DO ONE OF THESE, AND MAKE IT WORK: Put googie patents in google search field. Put 4689950 in google parent search field. No moving parts jet engine, NOT a pulse jet, NOT a ram jet. Probably tough to fabricate with fabrication methods at the time of it's invention, trivial with high strength high temp 3d printing. This guy is the second inventors name on the patent, the name may be familiar: http://en.m.wikipedia.org/wiki/Hans_von_Ohain

Dave B13

Patent 4789950 2nd drawing air goes in at the bottom impinging on vanes to generate centrificsl force. Hot air & combusted fuel exit at top impinging on vanes for straight flow out: http://www.google.com/patents/US4689950?dq=4689950&hl=en&sa=X&ei=odyAUpKdNMGSkQfW84DwDQ&ved=0CDgQ6AEwAA

Dave B13
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