February 2016 meeting

The RRS held our monthly meeting as scheduled, February 12, 2016.  Osvaldo called the meeting to order just before 8:00 pm.

On January 23rd, USC had three static fire tests at the RRS MTA with a 4″ x 18″ motor size. Thrust levels of 150 lbf for a duration of around 6 seconds with chamber pressures of 700 psig were measured.  Retaining ring failed on the second test.

Next launch at the MTA will be on February 27th with 10 students from Hermosa Valley Middle School launching Alphas. We hope to have an event like this once per trimester. Osvaldo built a really nice wooden carrying case for up to five alpha tubes which Larry was using to great convenience.

Questions about the purity of the zinc and sulfur in the RRS stock has come into question as the micrograin performance has been decreasing.  Chris found a process to purify the sulfur oxidizer. He is going to try the process on a small batch at the MTA.

Discussion of micrograin loading methods besides the typical “load a little, then gently bounce the casing” method were discussed.  Tamping the mixture from the top down historically has proven to be unreliable.  Casting the zinc-sulfur mixture using isopropyl alcohol was suggested but the drying process is very slow.  Frank had suggested using something neutral like flour to test the effectiveness of different loading methods by measuring the mass of the loaded powder in a standard sized case (known volume).

George Dosa who had a folder of many different publications of his from the RRS. He had pamphlets on practical topics in rocket building such as parachutes, nose cones, fin-and-bracket assemblies and flight tracking techniques. Some of these are already scanned in our RRS library.

George suggested having a symposium in the large hall in the Gardena Community Center as had been done in the past.   Participants such as experts from universities such USC, UCSD, UCLA and CSULB, organizations like the Calif. Science Center, and possibly people from industry (SpaceX, Aerojet-Rocketdyne,JPL) would give talks to the public on rocketry.

Frank showed a video about the Challenger disaster that happened 30 years ago on January 28th.  “Major Malfunction: Revisiting Challenger”.  Lots of good facts on the aspects of the launch and the decisions made prior to launch.

Meeting was adjourned at 9:29pm.  Osvaldo had promised a “show and tell” presentation for a rocket fin welding technique which can be brought up at the next meeting in March.   Next meeting will be Friday, March 11th.

 

3 thoughts on “February 2016 meeting

  1. Many years ago, there was a resin manufacturer, named Cal Polymers, that was also located on Gaylord St. in the Long Beach, CA area. Although they did not sell HTPB-type polymers at that time, maybe they might now and be a possible alternate source for the RRS if other sources become a problem. Perhaps, it would be worth checking out.
    Larry Teebken (Pyro Op)

    • Hi Larry,
      Just finished reading the RRS training course materials on solid propellants. Quite impressive. Hope you can stop by Gardena at tomorrow’s monthly meeting, 9/9/16?
      – Dave

  2. Thanks for the tip, Larry. I did some checking but I didn’t see Cal Polymers along Gaylord Street. I think I saw an address in Garden Grove, but that place looked to be residential. Where do people usually get HTPB type polymers?

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