MTA launch event, 2021-05-29

by Dave Nordling, Reaction Research Society


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 5-29-2021
Dave 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 inside
Dave 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.

president@rrs.org


MTA launch event, 2021-05-01

by Dave Nordling, Reaction Research Society


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,

president@rrs.org


MTA launch event, 2021-03-20

Dave Nordling, Reaction Research Society


The RRS held a launch event at our Mojave Test Area (MTA) on March 20, 2021, the spring equinox. COVID-19 still remains a threat so everyone had to observe protective protocols. We had a lot of wind that day making launch impractical, but we still were able to get many things done that day including another static fire of a hybrid motor, some system checkouts of the Gas Guzzler and a possible flight of the Solar Cat steam rocket. Osvaldo Tarditti was our pyrotechnic operator in charge. Also joining us that day was fellow Rockets 2nd Class pyrotechnic operator and RRS member, Jim Gross,

MOBILE TRAILER CLEANUP

Mike Gottlieb was a lifetime member of the RRS who passed away over 2 years ago. Years prior, he had acquired a surplus mobile trailer from the former Rockwell International company which was left to reside at the RRS MTA. By permission from his surviving family, this single-axle, climate controlled trailer has been donated to the society. The trailer was opened by the RRS president and the interior inspected by our members present at our March 2021 launch event.

The Rockwell mobile trailer at the RRS MTA
The interior needs a little work but otherwise has a lot of promise.
A spacious interior which could be used as an office space.

For now, the space will be used for light storage until more space can be acquired elsewhere. We used the time to reorganize the contents of our storage trailer. We hope to renovate this new mobile trailer soon and restore its climate control systems which will be convenient in the summer months.

PUBLIC ADDRESS SYSTEM AT THE MTA

During the cleaning and reorganization of our storage space, we pulled out the public address equipment we had. The 12 VDC battery powered system including loud speaker and microphones worked well in a test from the old blockhouse. The society has talked about having a more distributed system around the main areas of the site. This will require some further equipment purchases, but for now we have a core system to start from. The goal is to make coordination of our events easier to do when we have large groups of people at the MTA again. Further still, we’d like to coordinate launch timing better with our neighboring amateur rocketry group (FAR) to our south.

Keith Yoerg holds up the speaker after a successful test at the old blockhouse

NEW RESTROOM FACILITY

As discussed at the March 2021 monthly meeting, the society is going forward with building a new restroom facility with flushing toilets. This will be a big convenience to our visitors and members alike. The executive council has received bids and plans for the restroom and is working with suppliers to find the best solution given our budget. We are grateful to our generous benefactor and the many people who supported this project with their time and skills. More progress should be made soon as we would like to deploy this facility before the hot summer months arrive this year.

General placement of the proposed new restroom facility at the MTA subject to change and only for illustration..

FIRST FLIGHT OF THE SOLAR CAT FROM THE MTA

Bill Inman and new member Jonathan Wells returned to the MTA for another attempt to launch the solar powered steam rocket, the Solar Cat. He has been making many adjustments and had his first launch near his home in Carson City. Today would be his first launch of his Solar Cat from the MTA.

Bill Inman and his team set up his parabolic solar heating system for today’s sunny day at the MTA

Bill was able to work out minor problems on his trailer mounted systems last month and was fully ready to use his solar heating and tracking system for the hours necessary to reach launching temperatures of the stored water load in his steam rocket.

Bill has had some minor problems with the release system which led to a unintended release of the rocket. No one was injured but it did cost him several useful hours for insolation (heating). His second attempt was only a partial heat load but sufficient to conduct the first (technically second) flight at the MTA. Keith Yoerg managed to capture the short flight in the late afternoon. It’s a bit comical to watch given how short the flight was, but it is a significant milestone in getting this non-traditional form of liquid propulsion to work. We look forward to the advancements, Bill will make for future flights from the MTA.

The Solar Cat gets a clean release from the launcher and clears the rails on 3/20/2021.
The Solar Cat reaches its apogee while still in the frame of the video recording.
The wind pushes the rocket back to the launcher for an ungraceful return then clonking to the ground.

REBUILD AND SYSTEMS CHECK OF THE GAS GUZZLER

Wolfram Blume had made several improvements since his last flight attempt of his two-stage ramjet-solid motor rocket. He was able to correct software issues but also made physical feature changes to his booster. Wind speeds were excessive for much of the day, so he used his time at the MTA for fit checks while on the 1515 rail launcher.

Osvaldo Tarditti and Bill Janczewski observe Wolfram Blume’s operations with his ramjet upper stage in our loading area. No gasoline will be used in the maiden flight which will test the booster and staging systems. The unique design will need some flight testing before committing to a full flight with a fueled upper stage,
Wolfram Blume walks to the launch pad where his Gas Guzzler rocket rests on the pad.

Wolfram was able to conduct his tests making use of the 1515 rail launcher. He left in the afternoon after completing his tests and will return for our next launch event planned for April 10. 2021.

WIRELESS FIRE CONTROL AT THE MTA

Wireless fire control is a remote means of conducting launch without stringing long wire connections. This has been a controversial subject at the RRS with some of our members actively supporting using these systems and others being skeptical about their safety.

Richard Dierking mentioned the Wilson F/X wireless firing system which has been used at the Rocketry Organization of California (ROC) and at the Friends of Amateur Rocketry (FAR) site. Fellow RRS member, Dmitri Timohovich, has used Cobra Firing Systems for pyrotechnic events in the movie business with success. He brought one of these systems to demonstrate at the MTA with test bulbs. The 64-bit encryption in this system vastly reduces the possibility of stray signals causing an unintended firing.

Two 18-channel fire control boxes with the remote in the middle.

A decision was made at the March 2021 meeting to proceed with care by testing one of these wireless fire control systems with only low-power simple model rockets. We also thought meeting with a sales representative or technical advisor from a wireless fire control system manufacturer to explain the safety of these systems to the society would be an excellent idea. Some of our members have had a negative experience with these systems with unintentionally firing. Older wireless fire control systems have had safety issues. Safety in operations with pyrotechnics of any kind is of paramount importance.

wilsonfx.com

cobrafiringsystems.com

The RRS plans to educate themselves further about wireless firing system technology before making any further policy decisions. It is agreed that every pyro-op in charge at the event has the final say about what systems are and are not allowed at the event. The best course of action for any project leader is to discuss all aspects of their test or launch with the pyro-op in charge well in advance of the event at the MTA.

STATIC FIRING OF THE HYBRID MOTOR

The last two firings of the Contrails H222 38mm 16-inch hybrid motor left some questions about how reliable the ignition of the motor is. From both prior flights, it was evident that quick severance of the nylon plastic fill line at the launch command was not happening. Altitude was very low from such a powerful motor according to the curve. Since the last flight damaged the rocket body beyond repair, the next firing was intended to watch the startup sequence in careful detail under static conditions.

The motor survived in tact from the last short flight, The nozzle, spent grain and floating injector were shoved forward from the impact, but all parts were able to be removed, cleaned and reassembled for another firing with the last of my three fuel grains from the kit.

.The Contrails H222 motor reloaded for the third time.

The static test firing was done on the vertical test stand using a simple wooden fixture and 1/2-inch fasteners. The fixture was built quickly and unfortunately not perfectly. We had to fire the motor upside-down which is not representative of how the engine flies.

The vertical test stand holds the hybrid motor ready for firing with the fill line above and clear vent line below.
The 3/16” nylon fill line c0nnects to the floating injector push to connect fitting below the fuel grain and graphite nozzle held down by the snap-ring. The electric match is wrapped along side of and held against the fill line.
Acrylic 1/8” vent line from the top bulkhead push to connect fitting

The igniter used in the 3-20-2021 test used an electric match as was done in the second test. The kit comes with an electric resistor. In the first test, this was insufficient to get ignition and sever the fill line. Second firing used an electric match and a fragment of composite propellant. This achieved ignition but the fill line wasn’t fully severed. The third attempt used a similar load with a bit more composite propellant. The idea was to produce an ignition flame hot and fast enough to soften and sever the pressurized nylon fill line, With the escaping oxidizer liquid, the combustion should be enhanced and help sever the line. In practice, this doesn’t seem to occur quickly enough,

In the hybrid firing that day, the igniter fired and some chuffing from the nozzle was seen but the combustion was not sustained and the oxidizer supply emptied. The motor will be disassembled and inspected to see if all the composite propellant was consumed or if the nitrous oxide dispersed the pack before the full burn could finish.

A thin piece of composite propellant pressed against the electric match head pressed against the nylon fill line.
Floating injector loaded with the igniter and fill line strung through the fuel grain and nozzle.
The hybrid firing box with ruggedized 100-foot cable

The new hybrid rocket firing box with built-in solenoid valve and fire control.

MORE WATER ROCKETS

Dmitri upgraded his water rocket launch system to fire multiple rockets. He had a remote firing box which made it very easy to set up. The winds were too strong for any high altitude flights, but the modest water rockets were plenty of fun.

Water rockets lift off from the new blockhouse.

MODEL ROCKETS

The Yoerg Challenge started as a simple request to those attending our meeting on March 12, 2021 before the launch event: build as many model rockets from as many people as possible and launch them from the multi-wire launcher array that Keith built last month. Dmitri and I both answered the challenge for the event, Although many of our members have built many model rockets since they were kids, some of have not. For those experienced and inexperienced, the Yoerg Challenge was issued. More rockets at each successive event inspires others to build more rockets and more ambitious rocket builds. The RRS is for all forms of reaction propulsion even with a simple model kit.

The Estes Generoc E2X loaded with a C6-7 motor. An inexpensive and simple answer to the Yoerg Challenge,
Dmitri Timohovich built the Firestreak SST for the Yoerg Challenge
A few model rockets fly up and away at our arch.

At the end of the day, Keith and Dmitri launched their model rockets using small “A” sized motors to keep their altitudes low and avoid being carried far downrange with the high winds. I decided not to fly my first model as I left early that day. We hope others will build and bring theirs at our next event.

IN CONCLUSION

Next launch event will be April 10, 2021, with USC and member projects.