The RRS spent some more time working on the restroom facility at the Mojave Test Area. This project will bring a much desired convenience to our me,bers and future guests. It was a continuation of prior work which completed the installation of the fixtures and began the shower stall and internal plumbing.
The new firehouse container was placed on the adjacent concrete pads creating a small space in-between which will be for a safety shower in subsequent work next year.
Stainless steel threaded plugs were bought, lubricated and installed into the available 3/4-10 female anchors in the pad. This will better preserve the threads and minimize the sand collected in the holes. It is important that users of our pad clean out the holes and reinstall the plugs after each use.
The society is grateful to Osvaldo and Dimitri Timohovich for their continued support and labor on this project. We will have another work event on December 17-18, 2022 to finish the supply plumbing and begin the outlet plumbing. Our goal to finish the restroom by year’s end has a slim chance of success but we will continue through the winter months until it is operational.
At the next work event, members are welcome to join us and launch any rpckets they have. Pyro-ops are already present. Contact the RRS president if you’d like to use the Mojave Test Area on what will likely be the last event of the year.
by Frank Miuccio, Vice President, Reaction Research Society
The RRS held a launch event at our private testing site, the Mojave Test Area (MTA) on Saturday, May 21, 2022. Larry Hoffing was the pyrotechnic operator in charge. Temperatures were still mild and below 90 Fahrenheit. Winds were very slight for the entire event,
The main event was the launch of a number of student built model rocket kits using commercial motors. The second planned event was a member project, the two-stage Gas Guzzler ramjet, by Wolfram Blume. The third event was a cryogenic liquid tanking test at the vertical test standt of a portion of the Compton Comet liquid rocket overseen by Dave Nordling and Waldo Stakes.
The RRS teamed up with Boyle Heights YMCA and taught the students about rocketry over several weeks before the launch event. These students were the ones involved with the YMCA’s robotic program. We had 22 students come out to the MTA. During this launch day, we launched 23 Baby Bertha rockets all built from kits and custom painted by the students.
These rockets were launched first with smaller A8-3 engines. The students then retrieved their rockets and went into the Dosa Building and reassembled the parachutes for their next launch. The next launch was done with a larger C6-5 engine. All went well for the day.
We were able to use the new launch racks built by Dimitri Timohovich which gave us the capability to set up 18 rockets at a time which was our channel limit of our Cobra launch system. We have made a great investment with this safe and convenient product and more of our pyrotechnic operators are getting trained in its use thanks to Keith Yoerg.
The Boyle Heights YMCA wants to continue doing classes with the RRS. The students had a great experience.
The second event of that day was Wolfram Blume’s next attempt to launch the Gas Guzzler for its second flight. Significant design improvements were made. This very ambitious project is the result of a lot of complex design and 3D-printed parts which must fit correctly into their respective assemblies. Unfortunately, a critical fit problem with the nose piece prevented Wolfram from completing the build despite some on-the-spot adjustments. He postponed the flight to conduct minor repairs back at his home workshop. Wolfram plans to return to the MTA on June 4th at our next launch event with the UCLA Capstone Project.
The third operation at the MTA was a cryogenic liquid tanking test. The Compton Comet is a large liquid rocket being built by students and former students of Compton College. Led by Dave Nordling and Waldo Stakes, it is a project supported by the RRS and each person on the team is a member of the society. The Compton Comet describes both the vehicle which will be built and flown by the student members of the society and the team, itself. The ethanol/LOX vehicle uses a surplus 1500 lbf thrust chamber from an RM6000-4-1 engine once used to power the Bell X-1. The project is still in the latter parts of the design phase and important component testing is essential before committing more resources to construction. Bill Inman assisted with some of the operations that day.
The Compton Comet uses a pair of surplus stainless steel oxygen aircraft tanks. With the two tanks joined in series, a cold shock test with liquid nitrogen was done to verify their integrity after some minor welding was done. These tanks are decades old but have passed hydrotesting and visual inspection at the welded connections. These operations gave the student members hands-on experience with the safe transfer of cryogenic liquids. The society has acquired personnel protective equipment (PPE) such as polycarbonate faceshields, long elbow-length gloves and long cryogenic aprons to help future projects.
RRS member Diana Castillo recorded the time of each event and observations of the team as the tanking test progressed. The cryogenic liquid loading in uninsulated tanks is a slow process that loses much liquid to boiling. Eventually liquid nitrogen does accumulate in a tank if sufficient flow and capacity is available. The tank was vented at the top throughout the testing. A cryogenic rated relief valve to be used later in the full static fire was also present.
The second objective of this test was to demonstrate the pilot-operated solenoid valves intended for use as the main propellant valves of the vehicle. One of these high-pressure rated, normally-closed angle valves was connected at the bottom of this dual-tank setup. Cryogenic temperatures have been known to cause failures in electrical equipment. After attempting to fill the lower tank and having a significant amount of liquid nitrogen sitting at the inlet, the solenoid valve was well chilled for this functional test.
Before cryogenic loading, the valve was tested at ambient conditions using a pair of 12 VDC gel cells strapped in series to get the full 24 VDC needed to actuate the pilot solenoid. The circuit was switched by manually connecting the positive terminal by alligator clips. The distinct popping sound of the core stem moving inside was easily heard and very repeatable.
With the valve fully chilled after 40 minutes elapsed, the valve was tested again and functioned reliably. This is an important validation of the solenoid working in a relevant environment. The angle valve’s internal spring is very large and will require significant inlet pressure (150 psi?) to open. It was decided to leave the tanks vented at all times during this initial cryogenic liquid filling operation and leave a flow test for later. There were no signs of leakage from the valve outlet which was also a good result.
The Compton Comet project team recorded and discussed their findings. Leaving the tank vented, the liquid nitrogen boiled away in the warm afternoon. The remaining members enjoyed some time in the Dosa Building eating grilled burgers and hot dogs made by Waldo Stakes. Dimitri was able to reinforce the metal support legs of this donated propane gas grill to continue its service to the society.
The society cleared the areas and stored our gear. The next MTA event will be June 4th with the UCLA Senior Capstone Project. Wolfram Blume will return to fly the Gas Guzzler for a second flight. Dave Nordling will be the pyro-op in charge. Any other member projects are welcome and they should contact the RRS president to schedule them.
by Dave Nordling, President, Reaction Research Society
The RRS held a launch event at the Mojave Test Area on Saturday, 4/2/2022. Larry Hoffing was our pyrotechnic operator in charge. It was a very pleasant day with low winds for most of the day.
It was also the first time in a long time that all four members of the executive council were present at the same event. We took the opportunity to capture the moment in a photograph.
The primary project for that day was the launch of 15 Baby Bertha rockets made by the students of Nickerson Gardens over the six-week educational program the society held with the support of LAPD CSP. The rockets give the students a tangible sense of accomplishment and seeing them in flight from the MTA gives them good memories of what hard work can do.
There was an RRS standard alpha made for this occassion which flew at the end. It was prepared by our experienced pyro-op, Larry Hoffing, and made an impressive finish to this school event.
Secondarily, we had a few members of the USC RPL team out at our site to begin repairs of the concrete pad area used in their static fire tests. Removal of the male anchor bolts in USC’s custom mounting pattern were finally distorted too much to be useful. They were a frequent tripping hazard and their removal was a blessing.
Also, the USC RPL team made several contributions to improving the MTA site with earthwork, brush clearance, and just good old fashioned hard work. We’re grateful to them coming out to help keep the site in good shape,
The last portion of the day was spent launching a few more model and high-power rockets before the winds became too high. We used the time to plan our next event and rearranged our materials in our new storage container.
Our next monthly meeting is Friday, April 8th. Contact the RRS secretary for information.