MTA Firing Event, 2024-06-08

by Dave Nordling, Reaction Research Society

The Reaction Research Society (RRS) hosted a unique event with our clients, American Artist and the Los Angeles County Museum of Art (LACMA) at our private testing site, the Mojave Test Area (MTA). This was a two day event that began with an all-day filming and liquid engine static fire event on Saturday, June 8th at the RRS MTA. The next day began with a late luncheon, round-table discussion and short film presentation held at the Voyager Restaurant at the Mojave Air and Spaceport on Sunday, June 9th, 2024. The RRS was one of several invited guests including representatives of the Getty Foundation and Hyundai. Dr. Ayana Jamieson (Cal Poly Pomona) and members of JPL and LACMA also attended. The final event was a live performance and static firing of the replica engine at the RRS MTA which was a resounding success. I was the pyrotechnic operator in charge for both days with Dimitri Timohovich serving as my apprentice.

Seated from left to right, Adam Kleinman, American Artist and Dr. Ayana Jamieson, at the Voyager Restaurant in Mojave, California

Excerpted from LACMA press release:

American Artist: The Monophobic Response documents a meticulously crafted yet poetically altered re-creation of a pivotal 1936 static rocket engine test that initiated the United States’ venture into space travel. Inspired by Octavia E. Butler’s 1993 novel Parable of the Sower, which unfolds in the imagined dystopic year of 2024, American Artist performed and filmed The Monophobic Response in the Mojave Desert at the Reaction Research Society’s Mojave Test Area in the same summer of 2024. Artist’s interpretation involved an actual rocket engine test fire against the dry, desolate Californian landscape, creating eerie juxtapositions between Butler’s prescient visions and our troubling realities. Drawing parallels between Butler’s fictive 2024 U.S. presidential race led by an anti-space demagogue and the impending real-world election, this installation weaves together thought-provoking takes on our collective liberation and the concept of our shared “Destiny.”  

The 1936 GALCIT engine was one of the first American bi-propelllant rocket engines. The photo above is often referred to as ‘the Nativity scene’ of early American rocketry showing a young, scrappy group in the Arroyo Seco outside of Pasadena, California, making some of the first steps in a field of science not yet fully appreciated in their day.

The project with the RRS began in the Fall of 2022, when LACMA approached the president to gauge how practical it would be wanted to build and fire a full-sized replica of the same bi-propellant liquid rocket engine from the early days of the Guggenheim Aeronautical Laboratories of the California Institute of Technology (GALCIT). The project to replicate and fire this vintage engine was relatively simple for the RRS given our society’s long history with experimental propulsion. And so began the planning and study of what was known about one of the first liquid bi-propellant engines built in the United States from just a handful of scanned black and white grainy photos and hand sketches courtesy from JPL archives.

Thanks to this museum-funded project, with a few suppositions, some imagination and basic calculations, the RRS team was able to build a reasonably accurate replica of the 1936 GALCIT liquid methanol and gaseous oxygen bi-propellant rocket engine and it’s associated static fire vertical thrust stand. The most important aspect of designing this replica was not to aim for performance but rather to correctly interpret what the intended design might have been given the limited knowledge and resources of the period. To fire on command and operate safely were the two primary principles guiding this project.

RRS MTA, 6/1/2024, From left to right: Joe Dominguez, Dimitri Timohovich, Dave Nordling, Leanna Lincoln, Bill Nelson, Tre Willingham, David Stevenson, Manny Marquez, Aarington Mitchell

From careful examination of a cross-sectional drawing by Frank Malina and Jack Parsons, the scale size and key dimensions of the engine features were determined. A narrow half-angle of only 3 degrees was used in the nozzle design for this prototype ground test article. GALCIT must have been concerned with flow separation but had not yet developed a sense for how large the divergence angle could reasonably be. Design chamber pressure was not stated but it was assumed to be fairly low. Typically, amateur liquid propellant rocket engines operate around 300 psig. The design was shown to be sufficient for 500 psig, but in firing operations, the engine was run at only 50 psig both for safety and simplicity of the central task to get the engine to work on command and not overtax any component.

The engine was built in stackable steel slabs and a threaded in nozzle to form the desired internal chamber shape and bolted together. This practice is still used in university and professional test articles. The absence of sealing details in the sketches led our team to build graphoil gaskets that were custom built for the exact engine interfaces. It is very likely with this early engine design, as it is with engines built today, the first problem is combating leaks.

RRS testing found these graphoil gaskets lasted several prolonged firings. As the lower temperature binder material cooks out from the heat, the graphite portion still maintained pressure sealing as long as the joints remained undisturbed. Only after a hard ‘pop’ on the sixth engine firing did evidence of hot gas leakage occur. The RRS was able to disassemble, repack with new seals and reassemble the engine for another round of firing. No damage or erosion was seen on any interior surface including at the entrance to the nozzle throat.

The GALCIT engine design from the photos had what appeared to be a liquid water cooling jacket surrounding the outside of the engine head, middle and tail pieces. Photos show a sheet metal wrap which would infer a low pressure “dump cooling” approach. Photos show a square sheet metal can with a single feed line to allow gravity to fill the volume with liquid and let any steam or extra water to fall out of a short U-tube connected from a top port. For the sake of the exhibit and replicating the look of the engine tested at the Arroyo Seco, the dump water cooling port and sheet metal wrap and tank were added. In hot-fire testing, the feature proved to be unnecessary as the thermal mass of the engine steel plates was large enough that they never got excessively hot even after 20-30 seconds of continuous firing.

The engine was supported by a spring loaded shaft which fit into a black pipe. The design intended to have the pipe partially filled with water for dampening any oscillatory movement. The replica thrust stand was built with all of these features but no water was added as the friction between the parts was sufficient to dampen the movement. Corrections to the sketches seem to indicate internal support pieces were added to help guide the shaft’s movement along the center. Our own experience showed this to be a wise change so our replica also put these pieces inside for less troublesome movement. The rest of the thrust stand formed a simple flat base built from steel C-channel and angle materials. Seal welding of the pipe to the flat side of the C-channel was done but since no liquid fill was used, leakage in this area was of no concern. The thrust stand was calibrated with weights and found to be considerably and consistently linear as we had hoped based on the selected spring size we used that seemed to match the scale of the item in the period photos.

The original propellant feed system was done with manually operated hand valves with a person working from behind a single sandbag wall just a few feet away from the engine plume and noise. This was pretty gutsy and not a very safe approach but then again the early rocket pioneers at Caltech earned the moniker of “the suicide squad” for good reason. With safety in mind as required for all RRS operations and the members who would be firing the engine replica in the film, electrically activated pilot-operated solenoid valves were added to both propellant feed systems powered by 12-volt lead acid batteries.

The specific location was important for the film. American Artist and Chester Toye surveyed the MTA and found the empty space to our west and north with an open view of the northern mountain range and the western view of Koehn Dry Lake to be most scenic and appropriate for the film.

GALCIT-built prototype bipropellant rocket engine, October 1936, Arroyo Seco, outisde of Pasadena, California; image courtesy of JPL Archives

Sandbag walls were a common protective feature for early rocket experiments conducted in open field areas on the edge of town. The RRS painstakingly recreated these barriers thanks to the hard work of many volunteers. The society had an existing sand berm to protect the operators and all other spectators were at sufficient distance for the total impulse of the engine.

Our team saw no pictures of the firing box used by the GALCIT team in the 1936 Arroyo Seco firing, so we presumed to use a common metallic hobby box with the keyed safety switch required by California state law in amateur rocketry events. Some of our first engine firings with the complete feed and control systems were near the underground blockhouse to verify basic functions of the equipment and train operators in how system works and what to do if an anomaly occurs.

The oxidizer supply to the engine was simply gaseous oxygen from a high pressure tank. It’s likely the GALCIT team borrowed an oxygen gas bottle from a welding rig and used a low pressure regulator to control the flow into the engine. The RRS setup similarly used a high pressure regulator, commercial high pressure oxygen bottle and a swing-type check valve as seen in the oxygen supply manifold from archive photos.

The liquid methanol fuel supply in the 1936 GALCIT setup was likely pressure fed from a separate tank into the engine. A partial view of the top of what might have been the liquid run tank was seen in one of the JPL photos. In the modern replica, the RRS made a vertical welded pressure from 4-inch nominal stainless steel pipe and end caps welding on 1/2” NPT bung fittings. The tank is clamped to a pair of unistrut segments welded into a free-standing steel box frame structure that keeps everything steady and upright.

Gaseous nitrogen from a high pressure bottle and a high pressure regulator allowed controlled liquid flow into the engine. The liquid was loaded into the tank from the top when the tank is unpressurized. The fuel run tank manifold at the top has a seal plug and a manual valve. Below these but above the top of the tank is a pressure gauge and a spring-loaded relief valve set to 500 psig. The liquid fuel leaves the run tank at the bottom to feed the engine at the fuel inlet port. The bottom manifold on the fuel run tank has a second manual valve which opens for draining.

The GALCIT team likely used simple rubber tubing for both fuel and oxidizer feed. Information indicated that the GALCIT team had an oxygen fire in one of the lines. The GALCIT team likely added the swing check valve into their regulator manifold after this problem occurred. The RRS setup used 1/2” oxygen-cleaned and teflon-lined flex hoses to mitigate the threat of a hose becoming a fuel source in a pure oxygen environment. Modern flex hoses with their stainless steel wire braiding also offer much higher operating pressures for additional safety in operations in the event of surges or pops from the engine.

For the fuel line to the engine, a high quality braided and overwrapped hose was used but modern hoses have bright colors and text along the length which seemed to disrupt the vintage look of the replica setup. This was mitigated with large diameter black heat shrink tubing used as insulation over large wire gauge bundles. With a little teamwork, the long 1/2” diameter fuel hoses were covered in a tight-fitting, but non-descript black covering looking more like the simple black rubber tubing of the GALCIT setup. The added shrink-wrap layer also proved to be a good barrier against abrasion and a temporary sacrificial layer needed to protect the lines during engine fires that happened in early testing. Any damage to the outer layer was easily patched with simple black electrical tape keeping the look of a distressed experimental rig.

Methyl alcohol or methanol was once a common household or industrial solvent for a variety of purposes. In the modern day, common solvents tend to be a loosely controlled mixture of cheap hydrocarbon compounds readily available from refineries. To better know the proper mixture ratio for running the engine, the team stayed with sourcing pure methanol. Methanol in bulk 5 gallon metal containers is found in the sports car racing industry from a local supplier, Dion and Sons, in Van Nuys. An abundant supply was found to be fairly affordable.

Ignition of the engine was initially done by pyrotechnic means. An election match in a small packet of composite solid propellant shavings was our approach, but despite the sufficient energy in each of the charges, significant iterations and team ingenuity and striving for simplicity, the reliability of retaining the igniter charge in the nozzle long enough to achieve engine ignition more than once proved to be very frustrating. The GALCIT team used black powder packets and had similarly poor results in reliable retention of the igniter charge in their engine at start.

In the end, both the GALCIT team and the RRS opted for the spark ignition method which proved effective and repeatable for both teams. The GALCIT team likely used a Ford Model T spark coil still commonly available among vehicles at that time. An old Exide battery was seen in one of the period photos but next to it is what appears to be a spark coil or ‘buzz box’ which was likely used for engine ignition in later firing attempts.

The RRS used a model aircraft spark plug which used a similar voltage multiplier circuit likely found in a ‘buzz box’ that would fire a vintage automobile spark coil. Grounding to the large metal test stand and running a single wire into the nozzle or throat of the engine was likely how GALCIT succeeded. The RRS directly tapped the middle ring of the engine and submerged the spark plug end inside the thrust chamber. After seven firings, the spark plug still fired perfectly with minimal damage from the extended hot gas exposure.

The team considered using a glow plug type of ignition device but given the immediate and repeated success of the spark igniter, we did not attempt this approach. The method does have promise but it will have to be demonstrated in a later member project.

Although we were very successful, the RRS was wise enough to make many replacement seals of all joints and had several spare spark plugs should our luck not be as good.

Putting a lot of hard work upfront and running many tests proved to be the deciding factor in our project’s success.

LACMA-American Artist filming day at RRS MTA, 6/8/24, from left to right, Dimitri Timohovich, Frank Miuccio and Dave Nordling

Filming of the event proved to be challenging for many not used to prolonged hours in the Mojave desert heat. The early June temperatures reached 97F which marked the end of the milder and cooler spring just a week earlier. Although we had a field medic present to assist anyone overcome by the high temperatures, we had very few that required assistance. Still, operations always occur more slowly and less efficiently when the air temperatures get high. The film crew was able to create the scenes necessary and the engine was able to fire on command, but the long day tested everyone’s resolve and thanks to the professionalism of many people and acts of kindness large and small, the project achieved its objectives.

Flame color experiment with strontium chloride salt added to a small amount of liquid methanol burned in open air in a stainless steel dish.

For improved visibility of the engine plume in hot fire, strontium chloride salt was added to the liquid methanol providing a bright red/magenta color that could be seen even in the harsh glare of the mid-day sun. Other compounds were tried in similar open flame experiments but none produced a flame color bright enough to be seen in the harsh daylight of midday.

Once a reliable firing process was discovered, the team did not deviate making sure our team could execute our tasks without mistakes and our clients had the visual spectacle they required for this artistic endeavor.

Achieving a proper oxygen to fuel mixture ratio was an early problem, but easily solved by creating a wide range of orifice sizes through drilling set screws that allowed changes to be made quickly in this simple single element injector. Again, it bears mentioning that this project was to nearly fully replicate the early 1936 GALCIT design including injector features that are now known to be very substandard in terms of mixing and combustion efficiency.

Once the internal orifice screws properly balanced the oxidizer and fuel flow rates, the engine could be fired repeatedly. The engine proved to be very robust with little or no erosion on any of the interior surfaces even after 20-25 seconds of hot fire under the slightly fuel rich, methanol/oxygen flame temperatures. The custom-cut graphoil seals were able to last for several firings and only requiring replacement at the end of the day. The model aircraft spark plugs continued to operate even after half a dozen firings. Orifice tables were made that allowed for quick estimates of flow conditions under varying supply pressures. Although the intention was not to find any optimum conditions or settings, having the ability to adjust variables quickly in the field and knowing the directions of ‘goodness’ well justified the effort.

A very important part of the production involved two of our society members, Tre Willingham and Aarington Mitchell, who both acted in the film and fired the engine under the oversight of the pyrotechnic operator in charge, Dave Nordling, with fellow member Dimitri Timohovich’s assistance. They each gained practical experience in safely firing a rocket engine and managing the task in the summer heat of the Mojave Test Area. The society was able to give them sufficient field training in advance to allow them to act confidently and safely should problems arise. The yellow towel seen in the photos was used to cover the batteries and switchbox from the direct sunlight of that hot June afternoon in 2024.

Bill Nelson and Dave Nordling collected photos and videos taken from the RRS MTA over the months, weeks and days leading up to the event capturing the evolution of the replica engine and its analog thrust stand through hot-fire tests experiments, failures and finally successes

Bill Nelson is compiling a short presentation of the whole LACMA-American Artist project for the upcoming June 2024 monthly meeting on the 2nd Friday of each month (June 14 in this case). RRS monthly meetings are always held at 7:30pm at the Compton/Woodley Airport. Contact the RRS secretary, vice-president or president for the teleconference information.

Many RRS members contributed to the success of this project over the span of nine months leading up to this June 2024 event. The society would like to recognize and thank the following society members.

  • Dimitri Timohovich
  • Bill Nelson
  • Waldo Stakes
  • Tre Willingham
  • Aarington Mitchell
  • Manuel Marquez
  • Joe Dominguez
  • Leanna Lincoln
  • Chase Lang
  • Wilbur Owens
  • Frank Miuccio
  • Rushd Julfiker
  • Dave Nordling

The Reaction Research Society would like to thank the following individuals for their support, assistance and contributions to the success of this multifaceted project. The project was truly a great example of how all five studies of science, technology, engineering, art and mathematics, can be applied to produce something great.

  • American Artist
  • Chester Toye
  • Joel Ferree, LACMA
  • Dr. Ayana Jamieson, California Polytechnic University, Pomona
  • Dr. Eric Conway, Jet Propulsion Laboratory
  • Adam Kleinman
  • The student volunteers of the University of Michigan, Ann Arbor (MASA)
  • Aaron Miller, Weld Services Inc., Bonsall, CA
  • Mike Vanoverbeck, Compton College, Compton, CA
  • Ron Gerlach
  • Bill Heather
  • Compton/Woodley Airport, Compton, CA
  • Edwin “Ham” Metz, Linde Gases, Lancaster, CA
  • Dion & Sons, Racing Fuels, Van Nuys, CA
  • Titan Fittings, Denver, CO
  • Shane Hermanson, Field Medic
  • Karri and Derek Toth, Snake Wranglers, Palmdale, CA
  • Derek Honkawa, Friends of Amateur Rocketry

For questions and inquiries about similar projects and topics, contact the RRS president, Frank Miuccio.