I have been working on getting my igniter back up and going since my hiatus over the summer period. This has involved coming up a way to have removable but accurate orifices for the propellant injection. It took a while, but I found that a Lenox Laser 1/4-28 SS set screw is a perfect size to thread inside a 1/8 BSP nipple. I went for the optically measured option as this was the cheapest of which has a tolerance of 5% at 100+µm, more than good enough for this application.
My other bug to fix is that I was burning the electrode out of the spark plug, my injection holes are too close to it, so I will fix this by spacing the plug out a bit with more copper washers. Ultimately this will need to be addressed in version 2, of which I have a rough design nutted out and will start drawing up for printing later in the year.
(On a side note and abit of a plug, I am selling some SS tube which was intended for tanks, find them here.)
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Video still from yesterday's hot fire test of my 3D printed spark torch igniter. This will eventually be used to light a much larger rocket engine. At the moment, more tuning required. Video at https://youtu.be/eg9HlTKASrE More info at https://mach5lowdown.wordpress.com/spark-torch-igniter/ . . . . . #rocketengines #3dprinting #shapeways #space #technology #student #nz #rocket #igniter #flames #rocketengine #engineering #engineer #gopro #hero3plus
Over the last year I have been working on a 3D printed spark torch igniter, this has been a little side project while at university and eventually the experience gained will lead to this or a similar igniter used to light the main chamber of my rocket engine.
Yesterday I achieved the first hot fire tests of the igniter, the final test is shown below.
I ran through three hot fire tests, tuning it a bit each go. As can be seen, it is currently running oxygen-rich whereas it was designed to run fuel rich, the flame is too blue.
The design chamber pressure is 70 PSI, in this test it is ~85 PSI, so still some tuning of the inlet pressures required.
Before this test I had to replace a solenoid with another I had that has a smaller orifice than the fuel orifice on the igniter, although there is only 0.1mm difference this could slightly affect the performance. In the future, I will implement different sized orifice fittings to help fine tune it as I am not 100% on the size of the 3D printed orifices in the chamber.
Video Caption: Sep-Aug/2016
Development of Ignition system for liquid rocket engine using small hybrid rocket engine.
paraffine or acrylic resin / GOX hybrid rocket
Interstellar Technologies Inc.
Taiki-cho, Hokkaido, Japan
As this site is supposed to be amateur/experimental activities, I thought I would highlight some projects and components that would be of help to others in the area.
The first thing I will highlight is, how to make your own igniter for your liquid rocket engine project.