Wednesday, February 21, 2007

Some Hardware.

Here is a picture of my Pintile injector.
To give you an idea of scale the tip sticking up in the middle is 0.675 inches across. The small holes are 0.029" I don't have a water proof digital camera so I was unable to get pictures of the injector flowing.

I went to harbor frieght and bought a small sandblasting unit to use for pressurized flow testing. It has a large pressure tight opening on top to rapidly refill with water. It makes a heck of a squirt gun. Using that I flow tested both my lox and fuel flows for my injector. (I tested using water and adjusted the numbers for density) The fuel flow was about 35% low, and the lox flow was about 11% low. The 11% is close, but the 35% is off more than I would have expected. I'll try opening up the annular gap a tiny bit in next few days. It will be very hard to get it re centered. I'll probably end up making another one in the next few days .

Lastly here is a not quite ready to be fired picture of my igniter. The Aluminum box it's leaning on is the electronics for driving the shielded sparkplug.


Blogger Carl Tedesco said...


Just another observation on your low fuel-side flow during your flow test...

I personally think a radiused or chamfered inlet to the annular region will help most.However, you said the annular gap between your fuel plate and the pintle is .006". Looking at your photo I can clearly see machining marks from your lathe operation. Assuming the these turning grooves are .0005 to .001" deep, then you have a relatively rough surface which would be prone to resist flow. You could try getting a better surface finish either by slowing down your feedrate or post polishing/wet sanding.

Go Paul, go!

--- Carl

6:00 PM  

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