Saturday, March 31, 2007

Testing 3/31/07

Saturday we fired the 250 Lb motor with a new all copper pintile injector. The top end of the motor and the chamber wall worked fine. The Throat/end closure leaked and we melted the bottom end of the motor. It ran for 24 seconds, but the video camera died 20 seconds into the firing. The video is here.

After looking at the data, the chamber pressure started declining almost immediately, so I think the throat was coming apart as soon as we started. We still did not get any load cell data, the load cell worked in the shop, but not when the rocket was running. We have gotten this result twice. The Fuel feed pressure was also very noisy. In the chart below the Tank pressure sensors measure the tank pressure and the feed measures the pressure at the input to the motor after the throttle valves. At the end of the run the Lox tank and feed pressure drops quickly as we vent the tank, but the fuel pressure does not seem to change much. This is because we vent the fuel tank utalage into the motor for purge.

We will make a solid copper throat/chamber assembly and either test next weekend or the following week. It will depend on if I can find a 1st class Pyro op for this coming Saturday.
(It looks unlikely).

Today I started seriously looking at the paperwork necessary for my AST license. It seem like an appropriate day to start ;-) I wrote the beginnings of a hazard analysis and started looking at the procedures and verification processes necessary. Toward that end I also made a slightly more accurate rendering of the vehicle.

Sunday, March 18, 2007

Good Test Results...

The testing went well on Saturday.
We fired 1/4 of a vehicle. We had some software sequence problems that caused it to start roughly but we ran it for 16 seconds with no burn through or other damage.
The Video is here: Video

Sunday we disassembled the motor and analyzed the data. There is good news/bad news.
Good news, the regen motor shows no signs of melting. The bad news is we looked at the data and the presurization problem was more severe than we thought. We never got up to operating pressure. The operating pressure is supposed to be 80 to 250PSI we ran it from 40 to 120 during the test. So we did not run it anywhere near full throttle. This is actually useful data as it shows the engine is stable at low feed pressures, all the way down to 50 PSI. We got no load cell data.

We also fired the 650 Lb Ablative we tried to fire a few weeks ago.
That video is here

Friday, March 16, 2007

We have been busy...

Its 11:33PM and we just finished packing the truck.
Saturday we go out to the test site and test 3 things.

1)The 650LBF motor that we tried to fire last time.

2)A 250Lbf Motor in exactly the configuration we want for the NG-LLC.
This includes flight weight tanks and a torch igniter.

3)My Compressed Air stability software development vehicle.

The hardware is all 100% ready, both items #2, and #3 need a little software tweaking.
So rather than stay up all night, I'm going to get some sleep and work on it at the site. I may spend Saturday night and Test on Sunday as well.

I'll post video, results and news Sunday or Monday evening. I'm going to Space Access in Pheonix next weekend so if any regular readers are going make sure to say say hi.

Friday, March 02, 2007

Our first Mach diamonds.

Tonight I tested my igniter. It fired correctly on the first attempt.
I did not get chamber pressure so I need to figure that out before I fire it again.
In any case we made our first Mach diamonds.

Enjoy the video...(You tube)
Larger Version on my server.