Tag Archives: pyro-op

MTA Firing Report, 2025-11-01

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by Dave Nordling, Pyrotechnic Operator, RRS.ORG

The Reaction Research Society (RRS) held a liquid-fueled static fire event of the UCLA Rocket Project’s latest designs at the Mojave Test Area (MTA) on Saturday, November 1, 2025. We also had a member project that day with Austin Sennott and Charles Sharp launching three versions of their Half-Cat design.

The weather was quite good all day with very low winds and mild temperatures. The teams seemed well prepared and briefed me on their operations prior to commencing propellant operations. RRS member, Bill Nelson, assisted me in overseeing the event as my apprentice.

UCLA’s first static firing had a no-start condition on their igniter due to an open circuit which was easily corrected, but the team opened the run valves dumping the alcohol and liquid oxygen. For safety, the team ran the tanks until empty and simply waited to let the reminder of the liquid left in the horizontal internal space of the engine evaporate. UCLA would correct their operational mistakes on the next run.

While the UCLA engine was drying and the system rendered safe, the Half-Cat team got the next operation and conducted fuel filling and remote nitrous oxide filling. The Half-Cat design has flown nearly a hundred times at both the RRS MTA and FAR. They had three successful launches one right after the other. All vehicles were recovered with only one recovery system getting tangled. The HalfCats flown that day were gasoline and nitrous oxide which was loaded by a remote controlled system from the Garboden bunker.

UCLA returned to their static-fire operations after the HalfCat team was complete. They corrected the problem with the igniter and replaced the engine. The second run was a little more successful.

The UCLA team is testing the latest iteration of their ethanol (75% with water) and liquid oxygen impingement injector. It has an ablative liner running the whole chamber length to a graphite converging-diverging nozzle plug. An aluminum shell provides structural strength holding the assembly together. Ignition of the engine is by a nozzle-mounted pyrotechnic igniter (model rocket motor) held in place by an external clamp. The system has worked well in recent iterations.

Firing operations on this second attempt proceeded as planned with a clean, steady burn. Unfortunately, near the end of the run, the engine experienced burn-through and the chamber ruptured upstream of the nozzle in the upward location. Operations concluded safely and after a cooldown period, the engine was inspected. The data suggested the chamber pressure and mixture ratio was higher than predicted, but the ablation of the liner seemed relatively even circumferentially. The G10 plastic liner was thought to be able to last longer. Some concern was raised about variability in the product used today versus that used in the past. The failure was relatively benign and adjustments to the propellant feed should correct the issue.

The UCLA team intends to fly their next vehicle for the FAR-MARS competition at the end of the Spring Quarter 2026. The single engine tests are necessary steps in selecting the right design for the best outcome. Although the sun was getting low, UCLA requested a third test with their next engine prototype. The team worked quickly to install their last engine of that day.

The team finished the installation, verified no leakage and began fuel and oxidizer fill operations. Remote pressurization operations went well and the team proceeded into the count. The second engine fire was steady and ran to completion. The pressurants were bled down and the system rendered safe. After some cooling off, the engine was inspected.

Some sparks were seen exiting the plume and some graphite ablation (small chunks popping out) at two locations around the convergent side was detected during inspections after engine removal. This is somewhat normal for some types of graphite. The UCLA throat design has a more gentle contour that can permit some of this undesirable ablation pattern without opening the throat area and decreasing performance.

The second engine firing was a success in that it could be reused. UCLA had a third design that was 3D-printed and regeneratively cooled, but no further operations were permitted that day given the late hour. The UCLA team expressed interest in returning to the MTA for another round of testing. The RRS is glad to assist university teams with their projects.

During UCLA’s last installation operation, I took the time to look at the RRS’s second 60-foot launch rail which is still under construction. The Jurassic Launcher is so named as the underlying custom-built hydraulic lift system was one of a few used 30 years ago in the 1992 movie, Jurassic Park. The RRS was glad to purchase the system and is in the process of refurbishing it for liquid rockets needing a longer run length.

The steel backbone structure was a radio tower donated to the society by RRS member, Waldo Stakes. Some welding repairs have been completed and a short extension was put at the end to give a full 60-foot run length. The backbone needs a little more of the finer work to get the rail lugs installed. There is also some work to be done replacing hoses, cleaning and rebuilding valves and the pump if needed, building structural pieces, mounting and integration of the backbone and restoring the reservoir tank. Once finished, Jurassic Launcher will be a valuable asset to members and clients at the RRS MTA

Austin and Charles gathered all three of their rockets and gathered valuable data with their prolific and growing flight history at the RRS. Several members indicated their interest in building a HalfCat or a derivative version. I was also grateful to them for their professionalism and efficiency in operations. They were a good example for the teams at the MTA.

I was also grateful to the UCLA team who similarly showed maturity and patience in their operations which led to useful results despite a few setbacks. They policed the area for their trash and loaded their equipment for departure with practiced ease.

For those groups and members wanting to use the RRS MTA, contact the RRS president, Frank Miuccio. president@rrs.org

The next monthly meeting of the RRS is every 2nd Friday at the front office of the Compton/Woodley Airport. Next one will be December 12, 2025.

MTA Launch Event, 2024-09-07

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by Dave Nordling, RRS.ORG

The Reaction Research Society held a launch and firing event to honor the memory of Richard Garcia. His wife, Jeannie Riddles, his brother, Russell, and his aunt and cousin were present to witness the events of that day at our Mojave Test Area. I served as the pyrotechnic operator in charge with Dimitri Timohovich and Leanna Lincoln serving as my apprentices for the several operations we conducted that day with our membership and invited guests. RRS president, Frank Miuccio, was also present for this important event.

The safety briefing was given to all in attendance at 11AM with special recognition given to our honored guests. The weather was very hot (105F) which is typical for early September, but under low winds and a few high clouds.

We had several very different projects that day with many of our members coming to demonstrate their current projects and some bringing new builds. RRS member Jerry Fuller and his daughter Charlotte were also present that day.

Dimitri and Leanna mixed a batch of micrograin from the new zinc stock and our existing sulfur supplies. Chase Lang had a standard alpha and Bill Nelson a standard beta for launch. Both conducted safe loading operations in the RRS loading area.

With everyone under cover and passing air and road checks, the launch of the alpha still showed some of the initial low thurst stalling during firing before exiting the launch rail and being recovered downrange. The beta fired but showed an even lesser performance not managing to generate enough thrust to even leave the launch rail. Both rockets were returned for examination. Most likely cause is excessive moisture absorption into the sulfur, but that is under debate. Clumpiness of the powdered oxidizer was noticed during the mixing operation but a propellant sample burn beforehand showed no problems. it was thought that the tumbling process would be sufficient to homogenize and dry it out. Sulfur is not expensive and the society may consider buying fresh stock and improving the storage conditions.

Fourth year UCLA graduate student, Nick Kuenning, and his advisor, Prof. Mitch Spearrin, were present with a few UCLA Rocket Project members to static fire their new portable rig at the MTA. The main objective was to demonstrate the new oxidizer tank they added and run a prior engine design to check out the whole system. The test also served to show just how far UCLA has come in the many years since the liquid rocket program began at UCLA. Richard Garcia was one of the first RRS members to help UCLA in their early days of the Rocket Project. I attended UCLA PDR’s and CDR’s with him. Nick was just a freshman at the time. It was very generous of the UCLA team to conduct this firing in Richard’s honor during the last of the summer quarter when few students were back from vacation. The crew of four ran a clean and steady full-duration burn of their ablative lined engine on an impinging ethanol and LOX injector used with prior success. The burn went a full duration of 20 seconds with clean startup and shutdown. It is a very nice static fire rig and will give the team many opportunities to continue developing better engines. Nick is planning to speak at the RRS monthly meeting to share their results.

Mike Kramer and John Tsohas came to the RRS MTA as guests. Mike and John fired a few hybrid rockets that day and later joined as members. John had fired with the RRS several years ago and it was good to welcome him back. They had several successful launches and recoveries with the nitrous oxide loading and firing rig they brought.

Bill Inman brought the latest version of the Solar Cat which he and RRS member Dale Talcott built. The Solar Cat is a steam rocket mobile launcher that uses a parabolic reflector type of solar furnace for heating. It is an impressive piece of engineering with the ability to track the sun’s position in the sky and reach steam pressures up to 465 psig before moving the rocket tube into a vertical firing position. It is operated remotely and uses common off the shelf hardware.

After some considerable setup period the day prior in the northern expanse of the MTA, sun conditions that day were inconsistent however after 3:30pm a break in the clouds allowed a one hour period of insolation sufficient to reach adequate steam pressure for launch. Launch ended up not occurring as there was a mechanical snagging problem with one of the harnesses impeding the movement of the release mechanism.

Bill made the decision to abort the launch and remotely opened the vent to relieve the system dumping the load in a safe direction. Minor improvements will be made to the design to prevent similar issues and help avoid problems in deployment and stowing on the trailer. The Solar Cat design has advanced much and has had a few successful firings in Nevada. With Dale and Bill’s continued perserverence, the Solar Cat will one day fire from the MTA. It is a very long drive from Carson City, but Bill’s dedication to that test is a true honor to Richard Garcia and the passion he had for amateur and professional rocketry.

The RRS would like to thank our guests, our visitors and especially our membership for making this event possible.

The launch events will be discussed at the monthly meeting on Friday, September 13th, at 7:30pm at the front office of the Compton/Woodley Airport. RRS meetings are always on the 2nd Friday of each month. Contact the RRS secretary for details.

MTA Launch Event, 2024-07-15

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by the Reaction Research Society

The Reaction Research Society (RRS) hosted a launch event with Aerospace Corporation at our private testing facility, the Mojave Test Area (MTA), on Monday, July 15, 2024. Osvaldo Tarditti served as the pyrotechnic operator in charge for the event. Winds were pretty low but temperatures were over 100F which is normal for this season.

The RRS was glad to welcome Aerospace Corporation as a repeat client serving their launch needs. There were 25 model rockets propelled by “F” motors, mostly successful with a few a little unstable in flight.

Chase Lang had loaded his first standard alpha and flew it. Disappointingly, the alpha only flew 4 feet before landing safely back at the MTA. There seemed to be some trouble either in the quality of the new batch of propellants we acquired or a failure to build up pressure at the start with the burst disk. A good reason to try again soon. Some of our other new members have expressed interest in loading and flying their own micrograin rocket. Although now an obscure type of propellants, zinc and sulfur powders remain our signature rocket.

Chase Lang brought his large 10-inch diameter high-power rocket “Thumper” with a clean paint job and a big M1600 motor. Launched from the RRS 1515 rail at the MTA, it was a great sight reaching 4,700 feet. The dual-deployment chutes worked well and the rocket was recovered downrange.

The society is glad to have the interms of Aerospace Corporation at the MTA again and also grateful to members Chase and Jeff Lang for coming out and launching.

The RRS meets every 2nd Friday of each month at the front office of the Compton/Woodley Airport at 7:30pm. Next meeting of the Reaction Research Society will be August 9th. Contact the RRS president for details.