The society held a launch event at the Mojave Test Area on June 19th. With many people having other plans, we were sparsely attended but able to get a few things done. The winds were very low and sun was very hot that day (105 F) making it a challenge to operate at the site, but with each other’s help we managed. I was the pyrotechnic operator in charge that day. I had intended to bring my hybrid rocket for this event but wasn’t able to complete the rocket in time. It would be Bill Inman’s Solar Cat, a pair of micrograin alphas and witnessing the UCLA Prometheus team launch their hybrid rocket after getting a replacement nozzle from the motor supplier.
UCLA Prometheus team posing before bringing their hybrid rocket to the launch rail at FAR.
BILL INMAN’S SOLAR CAT
Bill Inman and Jon Wells made the journey from Nevada to demonstrate a new sun tracking system improvement to better automate the solar heating process with the parabolic mirror. Unfortunately, there were several problems with the installation that ultimately went unresolved for that day. A series of benchtop tests would be needed before bringing his combined solar collector and rail launcher back to the MTA for a launch.
Bill had also expressed concerns about vibration from over-the-road travel taking its toll on the structure. He was already considering a major rebuild of his parabolic collector with a wider aperture. The next iteration of the Solar Cat is also supposed to be larger in diameter and capacity. With the Solar Cat work at a halt, Bill and Jon came over to assist Manny Marquez and myself with the loading of a pair of RRS standard alphas.
A PAIR OF ALPHAS
Osvaldo Tarditti was unable to attend this event, but he did measure out the zinc and sulfur in separate pre-weighed bags and provided a clean pair of alpha parts complete with the nozzles and well-painted, turned and recovered aluminum nosecones. For our new members, the society likes to give the experience of micrograin rocketry. Manny, Bill and Jon would have their first experience loading and firing an alpha that day. The society hasn’t launched many micrograin rockets since before the pandemic.
Manny Marquez loads the pre-weighed charges of zinc and sulfur powders before closing up the mixing barrel.With the generator powering the electric motor driven roller, the drum sits and gently rolls mixing the zinc and sulfur to a consistent mixture.
Manny was a big help getting the equipment out and running. I was able to train him in the old RRS tradition of micrograin rocketry. With only two rockets, we gave the loading duties to Bill and Jon. For their handling of the dirty task of slowly loading the propellant tubes, they each got the honor of finishing the build and preparing for launch.
New member, Jon Wells (left) and returning member, Bill Inman (right) hold the first of two loaded alpha propellant tubes.Bill Inman doing the hook-up under oppressive heat.
I was able to teach Bill, Jon and Manny the safe procedure for hooking up back to the control box in the blockhouse. With a well rehearsed procedure including air-and-road checks, we notified FAR in advance of firing our two alphas for that day to prevent anyone from wandering downrange before we fired.
Still capture from the launch of Bill Inman’s alpha; fast as hell
We each got a good lesson in the value of teamwork and a renewed respect for the heat of summer. The micrograin rocket is a simple but powerful initiation into experimental rocketry.
We all brought a lot of ice and drinks for that day and it was a big help.
Our next event has not been scheduled but we do plan to return to the MTA in July 2021. For members interested in planning the next event at the MTA, contact the RRS president and the executive council.
The Reaction Research Society held a launch event at the Mojave Test Area mainly to support the UCLA Prometheus team for a static fire test of their high powered hybrid motor. UCLA chose one of the largest nitrous oxide hybrid motor designs, the M1575, made by Contrails Rocketry. Dave Crisalli was the pyrotechnic operator in charge for this event. I was his apprentice for the hybrid static fire.
There were three main activities at this event. The first was the UCLA Rocket Project making their preparations to launch their ethanol and LOX vehicle from the Friends of Amateur Rocketry (FAR) site from the 60-foot rail. FAR is just to the south of the RRS MTA where the UCLA Rocket Project had twice in one day static fired their 750 lbf liquid propellant rocket engine just four weeks earlier on 05-01-2021.
Weather conditions were ideal with winds being nearly still for most of the morning. This makes little difference for the hybrid motor static fire testing at the RRS MTA which was the second project by UCLA. Wind would factor heavily in the flight of the UCLA’s liquid rocket.
The third planned activity for UCLA was a series of model rocket flights from several high school teams mentored by UCLA graduate and undergraduate students. Still winds made for easier recovery of the first rockets launched that day.
UCLA Prometheus team prepares for static fire at the RRS MTA on 5-29-2021Dave Crisalli gives the MTA safety briefing for the event in the loading area where the model rockets were assembled for flight.UCLA graduate students conducted the model rocket launches from just west of the large test stand at the MTA
UCLA at the end of each Spring Quarter conducts a launch event where student groups build small rockets with egg payloads using single and dual-stage vehicles with model rocket class motors (G and under). UCLA graduate students and Professor Mitchell Spearrin were leading this event.
It is good experience for beginners and experts alike to build and fly model rockets., The RRS has it’s own such internal program called the Yoerg Challenge which is to motivate all members to build and fly a model rocket kit at least once from the RRS MTA. The RRS is known as an experimental society and not limited to the model rocket code, but we are also fully supportive of all forms of propulsion as long as it is safely conducted and compliant to the regulations set by the state of California.
As the UCLA hybrid rocket team was making their system checks, they discovered a problem in their nitrous filling system and valve commands. During this diagnostic period, some of the RRS members went to the nearby FAR site to see how the UCLA liquid rocket preparations were progressing.
UCLA’s liquid rocket set on the 60-foot rail launcher at FAR. The team preparing the vehicle for erecting, loading then flight.RRS members from left to right, Bill Inman, Waldo Stakes, John Wells and Manuel Marquez, inspect the UCLA liquid rocket on the 60-foot launcher deployed at the FAR site.A few last minute fixes and the rocket was made ready.The liquid rocket sits on the rail before raising it for launch.UCLA’s rocket is in position getting ready to clear the area for propellant loading and pressurization operations.
Some of the RRS members remained at the FAR site to witness the launch. After two years of design, planning, build and world pandemic, the UCLA team liquid rocket launch was an amazing success. Due to the relatively low winds that day under clear skies, recovery was made just under a mile away. Preliminary data from telemetry confirmed a new university team altitude record of 22,000 feet. It was an amazing sight to witness from the observation bunker at the RRS MTA.
UCLA’s liquid rocket had a perfect launch on 5-29-2021 setting a new altitude record of 22,000 feet by a university team. Photo by Xavier Marshall, RRS.
The UCLA Prometheus team had corrected their initial electrical problem and began the series of procedural checks to familiarize the new members of the hybrid rocket team. Some minor adjustments of the motor mount alignment was necessary before getting into test.
The UCLA Prometheus team makes some adjustments to better align the hybrid motor in the vertical skid mounted to classic I-beam at the RRS MTA.The nitrous oxide K-bottle sits inverted in the sloped stand to allow the liquid to flow from the port. Some nitrous oxide bottles come with an internal siphon line to avoid having to invert the container. The bottle is also being chilled with ice to keep the oxidizer sufficiently dense and improve performance in hot-fire.The top bulkhead of the hybrid motor is attached to the load cell for thrust measurement. A pressure transmitter is tapped into the nitrous oxide volume to further gauge performance.The high-powered hybrid motor by Contrails uses four 1/4-inch fill lines and a single smaller vent line from the same floating injector at the mid-point insideDave Crisalli (right) inspects the hybrid motor on the test rails before the firing UCLA Prometheus team tracks their written procedures as they progress to hot-fire in the old blockhouse.
The hybrid motor firing proceeded without further problems and resulted in a spectacular test meeting expected performance. Continuous thrust levels over 600 lbf were recorded but data analysis is still ongoing.
The hybrid motor at startup.The UCLA hybrid motor at full thrust. Chamber pressure was over 1000 psia.
The team had a second hybrid motor grain ready for another firing so they proceeded with disassembly and inspection of the parts. The floating injector seals were still in good condition but the graphite nozzle having survived many prior hot fire tests did not survive that day’s test. Although the throat was in good condition, the inlet taper had cracked requiring a replacement the team did not have.
The top half of the floating injector with its internal siphon tube protruding up to near the top bulkhead.The floating injector being removed from the lower half containing the spent fuel propellant grain.The floating injector was removed after hot-fire and the dual O-ring seals were inspected. Seals were ok for re-use.The nozzle assembly did not pass inspection after the first and only hot-fire on 05-29-2021.The graphite nozzle fractured at the inlet taper from the first and only firing that day.
UCLA Prometheus was pleased with the results from the single firing and will proceed with integrating the motor into their flight vehicle for a launch from FAR on June 19, 2021. The RRS will hold an event at the Mojave Test Area on this same Saturday for member projects and will observe the flight from our northern vantage point.
UCLA avionics team conducted a few tests on the GPS tracking module that will fly on their vehicle in June 2021.
In the last hours of the day, after most of the UCLA liquid and hybrid teams had cleared the area, packaged and carried away their trash, packed their equipment and departed the RRS MTA and FAR sites. The UCLA avionics team remained at the MTA to conduct another series of tests on the GPS tracking system. The society was glad to support this diligence which will help assure success in one of the most important aspects of rocketry which is data acquisition from telemetry. If there is no data, it didn’t happen.
For any group interested in using the RRS MTA for their propulsion related projects, download one of our Standard Record Forms from our RRS.ORG website and submit this request to the RRS president. The society has had a long relationship with UCLA and USC, but we are also supportive to any amateur, professional or academic groups wanting to learn from test.
The Reaction Research Society held an event at the Mojave Test Area (MTA) on May 1, 2021. Dave Crisalli was the pyrotechnic operator in charge. RRS president, Osvaldo Tarditti, was also present along with myself, It was not to be a launch event as all planned tests were static firings by the UCLA liquid rocket team and the UCLA hybrid motor team. The winds were very high that day consistently above 20 MPH and gusts above 50 MPH at times. The weather otherwise was very cooperative with comfortable temperatures.
Other than gusting and persistently hugh winds, it was a great day at the MTA on 5/1/2021
Dave Crisalli gave a safety briefing in the George Dosa building to all attendees before the first static fire campaign would begin. The RRS pyrotechnic operator in charge is responsible for the safety of all during the event. Hazard identification (spiders, snakes, sharp objects) and good practices (hydration, sunscreen) are always part of the briefing, One of the most important things, Dave Crisalli mentioned was not to be in a hurry. It is very important to take the proper time to do things correctly and safely even if it means not proceeding with the intended test that day. Taking your time means avoiding mistakes and improving your chances for success.
Xavier Marshall observes the UCLA hybrid motor controls setup at the RRS MTA on 5/1/2021.
RRS members, Bill Inman and John Wells came to the MTA for the event, but only as spectators. The Solar Cat project is still active and undergoing improvements to its sun tracking method. Bill is also expanding the collector area and adjusting the necessary support structures. It is likely Bill and John will be back for the next RRS MTA event.
Dave Crisalli (left) and Bill Inman (right) at the RRS MTA vertical test stand on 5/1/2021
Also in attendance was the Compton Comet team who have all recently joined the society as members. It was their first time visiting the MTA and getting a chance to see another university team conduct liquid rocket test operations at our vertical test stand.
Members of the Compton Comet team, Manuel Marquez, Aarington Mitchell, Tre Willingham (from left to right) wait at the Observation Bunker at the MTA for the hybrid motor firing with Waldo Stakes (at right).
RRS member, Wolfram Blume came by the RRS MTA to take measurements of the vertical test stand for a future static fire test of his ramjet upper stage engine. He intends to use a leaf-blower compressor motor to simulate foward air flow, but a lot of calculations and planning is required before proceeding. The vertical test stand has a winch and pulley system still attached from Richard Garcia’s liquid motor test in 2017. It should be adequate for Wolfram’s lifting needs when mounting the test equipment to the stand.
The vertical test stand with the winch and pulley system still mounted.
The UCLA team spent the night before on our site setting up their equipment. This advanced planning paid off as they were ready for the first of two hot-fires of the liquid rocket just past noon.
Camera adjustments made before the first hot fire of the UCLA liquid rocket on 5/1/2021
Often, it can take several hours to verify all systems are in good working order before testing especially with a liquid rocket, The hybrid rocket was no exception that day.
The UCLA hybrid motor team installs the fuel grain and nozzle into the 98mm standard motor casing,The UCLA hybrid motor mounted for static fire on the RRS MTA I-beam
One of the two load cells had failed so the two teams had to share the same load cell between the hybrid motor and liquid motor firings. UCLA chose to let the hybrid team go next after successful results were seen with the first firing, The UCLA hybrid motor team corrected a few issues and were able conduct a successful hot-fire by late afternoon.
The society members in attendance also had time to make some minor repairs to the new mobile trailer asset, A steel plate was added to keep intruders from entering. Thanks to Waldo Stakes for doing the welding for this temporary fix.
The mobile trailer at the RRS MTA needs a lot of repairs
There was sufficient daylight remaining for a second hot-fire of the UCLA liquid rocket, The team had another engine with the previous injector design from last built and ready with a fresh internal ablative liner. They had retanked another load of ethanol and the liquid oxygen cylinder had sufficient stores for another loading cycle.
Preparing for liquid oxygen transfer to the propellant tank
Thanks to the hard-won, acquired experience of the UCLA team and their commitment to training new members and holding to their proven procedures, they were able to conduct the second firing safely for an impressive finish that day.
The UCLA liquid rocket team poses before their liquid rocket after a second successful hot fire on the same day.
Initial data from both UCLA static firings of their liquid motor suggest that the 650 lbf nominal thrust motor outperformed expectations and will be ready for vehicle integration and flight by May 29, 2021. The UCLA team had reason to celebrate at the end of the day. The RRS was glad to be a part of UCLA’s continued campaign to fly liquid rockets that are competitive with any university team in the country.
For other universities interested in working with the RRS, please contact the society president submitting a Standard Record Form downloaded from our website,
