Open Source, 3D Printed Rocket Engines

A liquid-fuel rocket engine is just about the hardest thing anyone could ever build. There are considerations for thermodynamics, machining, electronics, material science, and software just to have something that won’t blow up on the test rig. The data to build a liquid engine isn’t easy to find, either: a lot of helpful info is classified or locked up in one of [Elon]’s file cabinets.

[Graham] over at Fubar Labs in New Jersey is working to change this. He’s developing an open source, 3D printed, liquid fuel rocket engine. Right now, it’s not going to fly, but that’s not the point: the first step towards developing a successful rocket is to develop a successful engine, and [Graham] is hard at work making this a reality.

This engine, powered by gaseous oxygen and ethanol, is designed for 3D printing. It’s actually a great use of the technology; SpaceX and NASA have produced 3D printed engine parts using DMLS printers, but [Graham] is using the much cheaper (and available at Shapeways) metal SLS printers to produce his engine. Rocket engines are extremely hard to manufacture with traditional methods, making 3D printing the perfect process for building a rocket engine.

So far, [Graham] has printed the engine, injector, and igniter, all for the purpose of shoving oxygen and ethanol into the combustion chamber, lighting it, and marveling at the Mach cones. You can see a video of that below, but there’s also a few incredible resources on GitHub, the Fubar Labs wiki, and a bunch of pictures and test results here.

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I Love the Smell of Rocket Candy in the Morning

[Grant Thompson aka “The King of Random”] has created a great tutorial on making sugar rocket motors. [Grant] is using a fuel based on potassium nitrate and sugar. Known as Rocket Candy or R-Candy in the amateur rocket community, various forms of this mixture have been used for decades. In fact, this is similar to one of the mixtures [Homer Hickam] and friends used to build rockets in his novel Rocket Boys.

[Grant] bought a cheap blender from the thrift store, which he used to grind his ingredients. You probably won’t want to use this blender for food after it’s been full of KNO3-based stump remover. The blender made quick work of grinding down the KNO3 to a fine powder. [Grant] then added in powdered sugar and carefully mixed the two by shaking, not by running the blender.

A 5″ length of schedule 40 PVC pipe made the rocket motor casing. The rocket motor’s end caps are made from ground clay cat litter. [Grant] rams the layers with a wooden dowel and hammer. First a top cap of clay, then the rocket fuel, then a bottom cap also of clay. With all the layers in place, he hand drilled a hole through the bottom cap and the entire fuel layer. Drilling all the way through turns the motor into a core burning rocket. The entire fuel cylinder burns away from the inside out, with more surface area than burning the end alone.

[Grant] tested his rocket motor at a remote location. We probably would have gone with an electric igniter rather than a fireworks style fuse, but the end result is the same. The rocket motor performed admirably, blasting up to over 2000 feet in altitude.

It goes without saying that working with solid rocket fuel isn’t something to be taken lightly. Something as simple as an air gap in the fuel could lead to a CATO, turning this rocket motor into a pipe bomb. We echo [Grant’s] suggestion to search for local amateur rocket clubs before trying this one at home.

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Homemade Bazooka Has Earned Its Stripes

Many of us dream of launching rockets from our shoulders, but [John] here actually did something about it.

This bazooka build started with a 6″ diameter PVC pipe. He mounted a length of 80/20 T-slotted aluminum extrusion to the pipe through a couple of wood blocks. [John] installed rail buttons on some Estes Alpha rockets which slide along nicely inside the T-slot. He welded a PVC cleanout fitting and plug to one end for easy access and gave her a nice paint job.

The ignition is simple: an irresistible red push button is wired to a 9V battery and a pair of alligator clips. [John] loads up a rocket, puts the gators on the wires of an igniter, pushes said button, and Bob’s your uncle. All he needs now is a pair of gun boats. Video of the build and some demonstrations we don’t necessarily recommend are after the jump.

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Building a rocket to launch your project into space

At Hackaday, we’re familiar with projects that say they’re exploring space. Most of the time, these are high altitude balloons that ascend up to 100,000 feet. Sure, this is very, very high, but it’s only about 1/3rd of the way to lower limit of what can be called space at 100 km or 62 miles. Now, we’re seeing the first steps towards embedding Arduinos, cameras, and other goodies into the celestial spheres with the NE-1 Rocket, a project by [Jonathan McCabe] in Madison, Wisconsin.

The goal of the NE-1 rocket is to launch a 5kg payload into a suborbital trajectory to a height of 120 kilometers. From there, the payload – be it an electronic, biological, or simple imaging experiment – will experience a few minutes of weightlessness before falling back to Earth under a parachute.

Getting into space without the help of a government space agency has been done a few times before, mostly with solid-fuel rockets. [Jonathan]’s system uses a liquid-fueled engine, fed with nitrous oxide as the oxidizer and a secret self-pressurizing liquid fuel. These are fed into an engine that uses a ‘cold wall vortex’ to cool the engine instead circulating fuel around the combustion chamber as in traditional engines.

[Jonathan] has already done a few static tests with a half-scale engine, and he already has a lot of the very hard-to-source components in his lab. It’s a promising project. It falls right in line with the ‘Hackaday Space Program’ idea we’ve been kicking around, and we’d be more than happy to see this project get off the ground

Milled water bottle rocket launcher pushes plastic containers to their limit


Building this launcher is simple if you already have a mill. It does a remarkable job of pressurizing and launching soda bottles which are partially filled with water. The main component of this is a triple-gasket stopper with a quick release.

The problem with a lot of these water bottle rocket projects is that they leak where the bottle meets the launcher. In most cases this is a good thing as it’s almost impossible to build up enough pressure to cause the bottle to fail. This system has no such built-in safety mechanism, which is why the test launch below is conducted from a safe distance. After seating the partially filled bottle on the launch platform it’s pressurized to around 100 PSI at which point a yank on the string lets it fly.

Most of the time we look on these as casual projects. But we figure this one is much more suited for a rocket club or hackerspace event.

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Rocketduino, for high-G, high altitude logging


Although the thrill of launching rockets is usually found in their safe decent back to Earth, eventually you’re going to want some data from your flight. Everything from barometric pressure, GPS logging, and acceleration data is a useful thing to have, especially if you’re trying to perfect your craft. [zortness] over on reddit created a data logging board created especially for amateur rocketry, a fabulous piece of work that stands up to the rigors of going very fast and very high.

The design of the board is a shield for the Arduino Mega and Due, and comes with enough sensors for over-analyzing any rocket flight. The GPS logs location and altitude at 66Hz, two accelerometers measure up to 55 G. Barometric, temperature, and compass sensors tell the ground station all the data they would need to know over a ZigBee 900MHz radio link.

Because this is an Arduino, setting up flight events such as deploying the main and drogue chutes are as easy as uploading a bit of code. [zortness] built this for a 4″ diameter rocket, but he says it might fit in a 3″ rocket. We just can’t wait to see some videos of it in action.

High powered rocket engines made from PVC pipe


For as much as we enjoy rockets, explosives, and other dangerous things, we haven’t said a word about the works of [Richard Nakka]. He’s the original hacker rocketeer with thousands of words dedicated to the craft of making things move straight up really fast. One of his more interesting builds is his series on building rocket engines out of PVC pipe written in conjunction with [Chuck Knight].

For the propellent grains, the PVC rocket didn’t use the usual potassium nitrate and sugar mixture of so many homebrew solid rockets. Instead, it uses Sorbitol, an artificial sweetener. While melting and casting the Sorbitol-based propellant grains is much easier than a sugar-based concoction,  the Sorbitol had much less thrust than a typical sugar rocket, making it the perfect candidate for a PVC engine.

For those of you wondering about the strength of a PVC engine casing, [Richard] does say making larger rocket engines out of 2 or 3-inch PVC may not make much sense due to the increased chamber pressures. There is a fairly clever reinforcement method for these PVC rockets (PDF warning) that involves using PVC couplers, but the experiments into the strength of these casings have yet to undertaken.

Thanks [Caley] for sending this one in.