By Brian Krassenstein | 3DPrint
Probably some of the most interesting 3D printing applications we have covered to date have been those involving engines that individuals and companies have been able to manufacture via this incredible technology. We’ve seen small-scale engine models 3D printed with plastics, as well as actual jet engines which have been 3D printed with metal using some of the most technologically advanced machines on the market. In fact, just the other week we covered a story in which researchers at Monash University, in Melbourne, Australia 3D printed two small metal jet engines.
There’s no doubt that some of the world’s best engineers are working on applications which could one day change the way engines are produced. One such engineer is Graham Sortino, based out of New Jersey. He has been working quietly on what we believe is the world’s first completely open source liquid fueled rocket engine, and best of all, it can be entirely 3D printed.
Sortino decided to use 3D printing for his engine’s construction because it enables him to quickly make changes as well as produce the necessary components much cheaper than traditional manufacturing methods.
For those who are not aware, a liquid fueled rocket engine uses both a liquid fuel and an oxidizer, such as liquid oxygen, stored in two separate tanks to propel a rocket forward. Although a liquid propelled engine is more complicated than an engine relying on solid propellent, the liquid fueled engines have several key advantages. For one the engine is able to be throttled by simply controlling the flow of the propellent within the combustion chamber. Starting and stopping such an engine is also much more easily managed.
Sortino has based his engine’s control on an Arduino Uno board and parts which can easily be 3D printed out of a metal material, which makes the open source design components readily available to whomever wishes to build or modify it. Using his design he has been able to accurately control the flow of the fuel as well as enable regenerative cooling within the engine.
The entire setup consists of three main parts, the igniter, injector, and the main engine body, all of which were 3D printed by Shapeways and ExOne.
“The igniter was printed by Shapeways, however, the injector and engine were printed by a company called ExOne,” explained Sortino to 3DPrint.com. “I believe (about 99% sure) that Shapeways subcontracts out their Stainless Steel / Bronze printing to ExOne regardless. The reason I used ExOne for some parts is because at the time they were a bit cheaper and they also helped a bit more with the design process. I currently switch back and forth between ExOne and Shapeways depending on the cost/complexity/turn-around time of the part I’m building.”
The completed engine has been designed to run off GOX/ethanol at 150psi and generate 50lbs of thrust, and although it proved difficult to generate enough thrust, the engine did fire successfully, and Sortino has learned a great deal from the initial testing of the engine so that he can improve it with future designs.
Sortino used a binary mixture of stainless steel and bronze to 3D print the engine components because of its hardness and high heat transfer. The total cost to have the parts 3D print was rather low. The 3D printed igniter ran Sortino $60, the injector $80, and the Engine $260, for a total of just $400 for the entire setup.
“My goal is to refine the design so that it is a true regenerative cooled engine, to reduce the printing cost as much as possible, and to open source the entire design,” Sortino explained to us. “I would like to get the whole cost down to less than $200, which would be a significant achievement given that it is almost impossible to buy a real liquid rocket engine for less than 1000’s of dollars.”
Ultimately Sortino would like to improve the state of rocket engine design by taking advantage of the complexities permitted by 3D printing. He also wants to take away some of the mystery perceived about the complexity of such engines, and perhaps even land a job with a company like Elon Musk’s SpaceX.
“While others (SpaceX/NASA) have 3D printed rocket engines recently, I’m pretty sure that I’m one of the first (or only) people to open source a rocket engine design,” explained Sortino. “A big reason for this is that there was traditionally a lot concern about releasing rocket engine information online due to ITAR requirements. This is similar to some of the issues that the quad-copter community had to overcome when getting started. However, I did receive permission (w/ some minor caveats) from the state department to release this via open source, which is why I’ve done so. Others are free to reuse, critique, or modify as they see fit and that’s a big motivation for me in putting this online.”
It will be very interesting to see how this open source project develops, and how it may eventually lead to all sorts of new designs for liquid fueled rocket engines.
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