MTA Launch Event, 2021-11-20

by Dave Nordling, Reaction Research Society


The UCLA Project Prometheus held a static fire event at the RRS MTA for two of their latest designs of their liquid rocket engine. The pyrotechnic operator in charge was Osvaldo Tarditti with Dimitri Timohovich and myself as apprentices for these two static fire operations. This was a liquid ethanol and oxygen engine of the same 1500 lbf design used in prior years. There was a change in the injector pattern and a new ablative liner was used in the first of two engines.

UCLA positions their equipment and makes final checks before inspection from the pyrotechnic operator.

UCLA had come to the MTA on the prior afternoon to begin their setup with plans to be ready for the first of two hotfires when the pyrotechnic operator was to arrive that day. UCLA was in fact ready and after a short review of all plumbing and changes made since last year’s testing followed by the basic safety briefing to all attendees the tanking operations began.

During the pandemic, UCLA had a long pause without access to their laboratory. This time allowed the team to collaborate remotely and consider improving their testing rig which was deployed at the MTA for the first time.

The first engine hotfire had a few delays from the igniter failing to light in the last seconds of the count. The count was recycled with the same result. After the avionics team corrected the problem and the oxidizer supply was replenished, UCLA returned to their countdown and had a generally successful hotfire. The test ran the whole duration but the chamber internal wall ablative liner seemed to not be sufficient and a breach of the chamber jacket was seen.

Chamber ruptured on the first engine at the end of the burn after the ablative wall expired.

After purging the engine and safing the ground test system, UCLA waited for the engine to cool. Photos were taken of the post-test conditions and we all took a break for lunch before swapping engines for the second of two planned tests.

The second engine installed and ready.

The second engine had the old ablative liner material and went full duration without any obvious trouble. Also, the second engine used a small solid motor on a 3D-printed clamp-on mount which worked well. Similarly the engine was purged and allowed to cool before its removal for inspection back at the university. UCLA will likely examine the igniter firing circuit and system before their next engine firing or flight.

Second hotfire went full duration.
Group photo at the end of a successful day.

The team was very proud of the progress made and the data gathered will be very useful in anchoring their next flight vehicle’s performance. UCLA intends to surpass 30,000 feet with this next flight to claim the FAR-MARS prize. UCLA is still the current record holder at 22,000 feet from last year’s flight. Vehicle dry weight reductions in this year’s design and minor improvements to other vehicle systems could make the difference in claiming the prize.

The sun setting after a pleasant afternoon at the RRS MTA.

The old blockhouse had it’s roof replaced two weeks ago thanks to Dimitri Timohovich and other RRS members who lended a hand. Trimming of the roof beams was finished and the blockhouse was used for the first time with UCLA’s liquid rocket static fire.

As UCLA was packing up to depart the MTA, we used the time to build another wire launcher rail for model rockets in upcoming school events with LAPD CSP. Dimitri and his son, Max, launched a few volleys of some water rockets using a special system using an air compressor and solenoid firing box built for remote charging of nitrous oxide based hybrid motors. The system worked well and it was great fun.

Dimitri Timohovich reloads a water rocket based from Smartwater one-liter plastic bottles.
Under his father’s supervision, Max Timohovich prepares to launch the next volley of water rockets in the last hour of sunlight.

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