Tag Archives: nitrous oxide

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 Firing Event, 2024-04-14

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by Dave Nordling, Reaction Research Society

The RRS had a short firing event at the Mojave Test Area on April 14, 2024. I was the pyrotechnic operator in charge that day. Although less rain fell than at prior events, the cold spring weather at Koehn (not so) Dry Lake remained but with low winds.

Rushd Julfiker, our director of research, had built his commercial hybrid motor and mounted it for a static firing. The Contrails 38mm, 16-inch motor is the same model I’ve used in the past with some success. Dimitri Timohovich also apprenticed under me and oversaw operations including remote fill and drain operations. Although a hybrid motor has a solid fuel grain, the compressed liquid oxidizer constitutes a liquid rocket classification by CALFIRE standards.

Dimitri Timohovich had built a portable switch box which I have used in prior operations. It simplifies connections and has the features necessary to assure safe and compliant operations. Rushd managed a good fill operation and a clean ignition. Severing the nylon feedline often requires a boosted charge on top of the electric match. A small portion of aluminum/HTPB/AP composite grain is sufficient to cleanly sever the line while assuring sufficient ignition energy to start the fuel grain burning in the flow of the exiting nitrous oxide.

The basic objective of loading and static firing a hybrid motor at the RRS MTA was met. Rushd and Dimitri are both seeking their Class 1 pyro-op licenses and this experience adds to their growing base. After safing the nitrous system, the motor and mounting was removed and stored for a reloading later. Rushd intends to fire again at a later date, but with a load cell in the system to record thrust.

Dimitri and I observed the restroom facility (Bldg 12) at the MTA now has a functional shower inside and a working hot water system. We thank Osvaldo Tarditti for making several trips to the MTA to complete this amenity for our members and guests.

Dimitri and I discussed and examined the propellant feed system for the upcoming LACMA project with American Artist. Most fittings were present, but some changes to the schematic were necessary to simplify our first firing operations expected next month in May 2024.

For those interested in using the RRS MTA, contact the RRS president.

MTA Work Event – January 20th, 2024

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by Dave Nordling and Joel Cool-Panama, Secretary, RRS.ORG

The RRS held a work event at the Mojave Test Area (MTA) on Saturday, January 20th. The primary purpose of this meeting was to give Joel Feree, our contact with the Los Angeles County Museum of Art (LACMA), an in-person tour of the whole MTA, so that he could get an idea as to what we were working with for our collaboration with American Artist which will involve the recreation of the 1936 Guggenheim Aeronautical Laboratory at the California Institute of Technology (GALCIT) prototype liquid rocket engine. This was Joel Ferree’s first time at the MTA and he gained much insight into how we’ll be seeing the project through. Dimitri Timohovich also used his experience in the film industry to highlight some practical aspects for the production. Following this meeting, Dave Nordling, Dimitri, and Joel Ferree came up with a timeline for the project. Dave Nordling, serving as the project leader, is working hard to get hardware ready for an initial firing by our membership at the MTA. Once the system is proven to work reliably and safely, the static firing of this replica will be the centerpiece of the filming to take place at the MTA.

On the same day, four student representatives of Loyola Marymount University’s rocketry team came to meet with Dave Nordling. They intend to build a custom hybrid motor, which they plan to static fire at the MTA. Dave gave them some points on their motor and feed system designs, which they can certainly appreciate, given that this is their first experimental rocket project. Rushd Julfiker and Dave will continue to advise the team on their propellant loading system and ignition system, and they may well use a firing box of Dimitri’s design.

While there, Dave and Dimitri worked on moving some of the society assets from the Dosa Building to the new Bldg. 14 office container.  This was done partly to declutter the working space, in order to make it into a meeting and workspace once more. If the lease does end next year, then Polaris will be removing many items of theirs which are also in the Dosa Building, including refrigerators, stove, and laminar flow bench. Polaris is required according to the terms of the lease to notify the RRS Executive Council of the movement of their assets.

According to Dimitri, a company called Tortuga Industries has reportedly bought 183 acres of land along Munsey Road. According to the rumors, they are looking to turn their parcel into a private duck hunting reserve, complete with a large pond.

Dimitri also reported that Crisalli is taking the initiative to fix the northern road running along the eastern side of the MTA property. Gordon has so far filled in the trench near the northeastern corner of the property, removed the concrete barricades, and installed a gate across the road. He has reportedly been using this northern route himself, dragging it several times in the process. He reports that the 4 miles of the northern road leading to the highway is now certainly passable, albeit the creek bed is still soft as of this writing. The RRS still recommends all visitors and users of the MTA continue to use the western (Munsey) road from Cantil until further improvements can be made.  The RRS MTA has access gates along the eastern border but they are rarely used.

Next monthly meeting will be February 9th.

Next work event at the MTA is planned for February 17th. This will depend on planned Polaris operations which could close the access easement road. Coordination with Polaris will be required.