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.

1 comment:

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