Monday, November 19, 2007

Side by Side Comparison

I fired two motors this past Saturday. One was an AP based motor and the other was a KNO3 based motor. Both motors were of approximately the same total impulse, but it wasn't really a fair comparison. The KNO3 motor used Xylitol for the fuel. I first heard about this sugar on Scott Fintels web site, and it was available at the local Whole Foods store. It has a low melting point and casts very nicely, the problem was that the grains took a long time to cure, weeks in fact. Anyhow, the propellant in the AP motor is fully characterized and the propellant in the KNO3 motor not so much. The side by side comparison is still interesting to watch though.

Sunday, November 18, 2007

Composite motor class

I took part in a composite motor class this past weekend. The class was taught by Dave Reese and was conducted at the Friends of Amateur Rocketry site. The class was a lot of fun and full of lots of useful information. Dave is currently a student a USC and I'm sure that he is very busy but despite this he did a great job organizing and conducing the class. The motor that we prepped propellant for was based on standard high powered rocketry hardware of which I have none, so I made some hardware based on drawings that I found on the Loki Research website. The hardware worked really well; I like the simplicity of the Loki design. Here is a video of the class motor that I static tested, I didn't have any instrumentation partly because I didn't want to risk any equipment on untested hardware and a propellant that I don't have much experience with, but mostly because I've been so busy lately that I just didn't have time to get anything together in time. The design/propellant is pretty well characterized though. The thrust produced should have been in the neighborhood of 90lbs with and Isp of around 185-190.

The Paul Breeds of Unreasonable Rocket were also at the site. Paul senior was flying an RC helicopter loaded with telemetry to gain information for their Lunar Lander Challenge quest.

Saturday, November 3, 2007

Composite Propellant Class

Later this month I'll be participating in a composite propellant class at the FAR site. The class is being taught by Dave Reese. Dave's a student at USC and was involved with this awesome project flown at the RRS some time ago. Photo by James Davidson.

Here is a picture of some of the 38mm hardware that I made myself for the class. I only had to buy the tubing. I bought enough for three casings for under $30. I had enough "scrap" pieces laying around for the bulkheads and nozzles.