By Dave Nordling, President, Reaction Research Society
The RRS held a launch event on Saturday, June 4, 2022, at our Mojave Test Area (MTA). I was the pyro-op in charge. Winds were brisk and steady, but still under the 25 MPH limit. We had two operations that day.
The first was the UCLA Senior Capstone project led by Professor Brett Lopez. This quarterly class has seniors build and balance their own rockets from scratch. They load F-sized motors and fly them at the end of the quarter to prove their team’s skills in flight.
The UCLA students gather their materials in the propellant loading area.
Secondly, RRS member Wolfram Blume returned to the MTA with the latest rebuild of the Gas Guzzler. He had concerns about flying in the strong winds that day so he limited his work to testing the staging system with both halves on the 1515 rail. Bill Inman and new member, Dale, offered their assistamce in positioning the rocket on the rail.
Dale, Wolfram and Bill Inman
Bill Inman and Dale assisted Wolfram in trying out the new staging system in the Gas Guzzler. The old system (e.g., last December) was a hassle and required assembling the upper stage (main body tube, cowling, nose cone) on the rail with a screw driver and a step ladder. The mating of the booster thrust rods into the upper stage was very difficult. So after December, he redesigned and rebuilt the thrust rods and the staging system. The result was a successful design. The new system is fairly easy to stage on the rail, does not require any assembly (with the ever-present danger of losing small screws) and does not require a ladder. Wolfram feels good about this system for future launches.
The Gas Guzzler during its fit check on 6/4/2022
Wolfram doesn’t think he’ll make it back to the MTA until the summer heat is over. His goals for the summer both involve the fuel system:
The flameholder is the ramjet needs to ignite every time.
The ramjet slows down very quickly after stage separation (25m/sec/sec = 60mph/sec), so the ramjet must ignite within less than 2 seconds after stage separation; less than 1 second would be better.
Using the 270-volt, 3-phase electricity at Wolfram’s laboratory, he can run a 20hp air blower which can mimic the air flow at stage separation with a K-motor in the booster (175 m/sec). The blower can be run higher to mimic stage-separation flight speeds of about 250 m/sec which is just below the separation speed of an L-motor in the booster (280-300 m/sec).
Wolfram’s workshop is good for the tuning and testing the flameholder. but running the main burner would require returning to the MTA. The main fuel flow could be tuned using water. After the summer’s heat is over, he will return to the MTA and finish testing the parachute system. The first powered flight of the ramjet with a short – 5 second burn is under discussion.
This short event was also a good time to clean up the site a bit. The society has big plans for the summer including some much anticipated facility upgrades.
The next monthly meeting will be June 10th (2nd Friday of each month) by teleconference. Contact the RRS secretary for details.
by Frank Miuccio, Vice President, Reaction Research Society
The RRS held a launch event at our private testing site, the Mojave Test Area (MTA) on Saturday, May 21, 2022. Larry Hoffing was the pyrotechnic operator in charge. Temperatures were still mild and below 90 Fahrenheit. Winds were very slight for the entire event,
The main event was the launch of a number of student built model rocket kits using commercial motors. The second planned event was a member project, the two-stage Gas Guzzler ramjet, by Wolfram Blume. The third event was a cryogenic liquid tanking test at the vertical test standt of a portion of the Compton Comet liquid rocket overseen by Dave Nordling and Waldo Stakes.
Students prepare to hear the safety briefing after their arrival at the RRS MTA
The RRS teamed up with Boyle Heights YMCA and taught the students about rocketry over several weeks before the launch event. These students were the ones involved with the YMCA’s robotic program. We had 22 students come out to the MTA. During this launch day, we launched 23 Baby Bertha rockets all built from kits and custom painted by the students.
Students and mentors observe the safety briefing and propellant burn demonstration.
These rockets were launched first with smaller A8-3 engines. The students then retrieved their rockets and went into the Dosa Building and reassembled the parachutes for their next launch. The next launch was done with a larger C6-5 engine. All went well for the day.
Larry Hoffing and Frank Miuccio prepare the new launch racks for the Boyle Heights flights.
We were able to use the new launch racks built by Dimitri Timohovich which gave us the capability to set up 18 rockets at a time which was our channel limit of our Cobra launch system. We have made a great investment with this safe and convenient product and more of our pyrotechnic operators are getting trained in its use thanks to Keith Yoerg.
The Boyle Heights YMCA wants to continue doing classes with the RRS. The students had a great experience.
Boyle Heights students observe the launch of their rockets from the observation bunker.
The second event of that day was Wolfram Blume’s next attempt to launch the Gas Guzzler for its second flight. Significant design improvements were made. This very ambitious project is the result of a lot of complex design and 3D-printed parts which must fit correctly into their respective assemblies. Unfortunately, a critical fit problem with the nose piece prevented Wolfram from completing the build despite some on-the-spot adjustments. He postponed the flight to conduct minor repairs back at his home workshop. Wolfram plans to return to the MTA on June 4th at our next launch event with the UCLA Capstone Project.
The gasoline fueled ramjet upper stage and solid motor powered booster sit ready for inspection.L-sized high-powered motor to the left, ramjet second stage to the right.
The third operation at the MTA was a cryogenic liquid tanking test. The Compton Comet is a large liquid rocket being built by students and former students of Compton College. Led by Dave Nordling and Waldo Stakes, it is a project supported by the RRS and each person on the team is a member of the society. The Compton Comet describes both the vehicle which will be built and flown by the student members of the society and the team, itself. The ethanol/LOX vehicle uses a surplus 1500 lbf thrust chamber from an RM6000-4-1 engine once used to power the Bell X-1. The project is still in the latter parts of the design phase and important component testing is essential before committing more resources to construction. Bill Inman assisted with some of the operations that day.
Waldo Stakes (sleeveless, to the right) explains the goals of the cryogenic testing.Schematic of a cryogenic liquid cylinder from Chart Industries literatureIdentification of the parts on a cryogenic liquid cylinder, medium-pressure unit, Chart Industries
The Compton Comet uses a pair of surplus stainless steel oxygen aircraft tanks. With the two tanks joined in series, a cold shock test with liquid nitrogen was done to verify their integrity after some minor welding was done. These tanks are decades old but have passed hydrotesting and visual inspection at the welded connections. These operations gave the student members hands-on experience with the safe transfer of cryogenic liquids. The society has acquired personnel protective equipment (PPE) such as polycarbonate faceshields, long elbow-length gloves and long cryogenic aprons to help future projects.
LN2 cryogenic liquid cylinder and vacuum jacketed transfer hose connected to the dual propellant tanks supported verticallyRRS members Drake Pearson and Aarington Mitchell, observe the start of cryogenic liquid loading wearing their PPE. All others stand back.
RRS member Diana Castillo recorded the time of each event and observations of the team as the tanking test progressed. The cryogenic liquid loading in uninsulated tanks is a slow process that loses much liquid to boiling. Eventually liquid nitrogen does accumulate in a tank if sufficient flow and capacity is available. The tank was vented at the top throughout the testing. A cryogenic rated relief valve to be used later in the full static fire was also present.
Filling from the top tank, the lower tank never reached full. The design is being reconsidered.
The second objective of this test was to demonstrate the pilot-operated solenoid valves intended for use as the main propellant valves of the vehicle. One of these high-pressure rated, normally-closed angle valves was connected at the bottom of this dual-tank setup. Cryogenic temperatures have been known to cause failures in electrical equipment. After attempting to fill the lower tank and having a significant amount of liquid nitrogen sitting at the inlet, the solenoid valve was well chilled for this functional test.
End view of the 2-prong Bendix (Amphenol) electrical connector.Unable to get a suitable two-prong plug to the MIL-SPEC interface, the connector wires inside were used to manually actuate the 24 VDC 1Amp valve.
Before cryogenic loading, the valve was tested at ambient conditions using a pair of 12 VDC gel cells strapped in series to get the full 24 VDC needed to actuate the pilot solenoid. The circuit was switched by manually connecting the positive terminal by alligator clips. The distinct popping sound of the core stem moving inside was easily heard and very repeatable.
With the valve fully chilled after 40 minutes elapsed, the valve was tested again and functioned reliably. This is an important validation of the solenoid working in a relevant environment. The angle valve’s internal spring is very large and will require significant inlet pressure (150 psi?) to open. It was decided to leave the tanks vented at all times during this initial cryogenic liquid filling operation and leave a flow test for later. There were no signs of leakage from the valve outlet which was also a good result.
The Compton Comet project team recorded and discussed their findings. Leaving the tank vented, the liquid nitrogen boiled away in the warm afternoon. The remaining members enjoyed some time in the Dosa Building eating grilled burgers and hot dogs made by Waldo Stakes. Dimitri was able to reinforce the metal support legs of this donated propane gas grill to continue its service to the society.
The society cleared the areas and stored our gear. The next MTA event will be June 4th with the UCLA Senior Capstone Project. Wolfram Blume will return to fly the Gas Guzzler for a second flight. Dave Nordling will be the pyro-op in charge. Any other member projects are welcome and they should contact the RRS president to schedule them.
The latest meeting of the Reaction Research Society was held last Friday, May 13th 2022 and had seventeen attendees.
Screenshot of discussion during the monthly meeting
UPCOMING MTA EVENTS
The meeting began with a discussion of the launch event upcoming at the MTA. Events planned for Saturday, May 21st include:
30 students from a LAPD class launching Baby Bertha model rockets 2 times each
Launch of Wolfram Blume’s Gas Guzzler
Cryogenic testing of Compton Comet tanks
Dimitri has started work on a new set of launch pads to accommodate up to 18 model rockets (which is the number of separate igniters each Cobra firing module can accommodate). The high number of launches we expect to complete this weekend will give us a chance to train members who might be interested in learning how to use the relatively new Cobra Firing System.
Progress on the launch pads Dimitri is building
Wolfram is planning to conduct another launch of his rocket Gas Guzzler, hopefully fixing issues with the parachute system from the last launch. Several members of the Compton Comet team plan to conduct cryogenic shock testing of hardware for their liquid rocket project. Compton Comet team members agreed to send a list of attendees to the RRS President & Treasurer to help confirm that all the members have current membership and waivers on file.
REVIEW OF RECENT MTA EVENTS
We then discussed the recent MTA event where the USCRPL launched a rocket called “Jawbone.” Frank showed a YouTube video that the group made after the launch.
RECAP OF RECENT EXECUTIVE COUNCIL MEETINGS
The RRS Executive Council (EC) met in each of the 4 weeks leading up to the May monthly meeting, and the council provided a brief synopsis of the topics and decisions made in those meetings to the membership. Specifically, one EC meeting included RRS members Richard Dierking and Kent Schwitkis and was focused on emergency preparedness at the MTA, including what infrastructure improvements might be useful from a safety standpoint. Another meeting was attended by Xavier Marshall and focused on modernizing and digitizing the administrative processes of the RRS. The other 2 meetings focused primarily on the new RRS bathroom, and decisions were reached on selecting a contractor as well as construction material (concrete) for the septic tank. The council hopes the septic system will be installed by the end of June, with the bathroom container installed not long thereafter.
Example of a concrete septic tank
DISCUSSION OF MONTHLY MEETING LAYOUT
After several monthly meetings with lengthy presentations, the EC decided to open a discussion with current members on the layout for monthly meetings. The general consensus was that presentations are an appreciated and valued part of the meetings, but that a hard time-limit should be enforced to limit meetings running too late into the night. Many members agreed that 20 minutes is a reasonable limit, and that Q&A periods should be limited as well to avoid lengthy questions that become their own monologues. Most members in attendance agreed that starting the meetings with presentations would be preferable to leaving presentations until the end of each meeting.
PROMOTION OF THE RRS& OTHER ITEMS
Our Vice President Frank Muiccio was asked to give a radio interview as part of a segment on local heroes. The interview will be on AirTalk with Larry Mantle on the local NPR radio station 89.3 KPCC Thursday, May 19th at 11:45 am and can be heard on the radio or streaming on their website. Frank also updated the society on the possibility of an update to the documentary about the RRS youth outreach programs called Rockets in the Projects.
This opened a discussion about the possibility of expanding the classes to potentially include entries in competitions like the TARC challenge. Jerry Fuller mentioned that his local high school in Palos Verdes has had many groups successfully compete in this challenge, and expressed interest in helping connect the RRS with the instructors of that group.
Although Jim Gross was unable to attend the meeting, he sent along information that he wanted the membership to be aware of:
Wanted to let the Society members know there is a 5-day “Cryogenic Engineering & Safety Course” scheduled for 1-5 August 2022 at the Colorado School of Mines. The price is $3,250 per student. This MIGHT be useful for anyone going for a Rockets Class 1 Pyro. Op. License. I’ve never taken it, so I am not sure. More info is available from 1 (305) 972-8847 or www.cryocourses.com or via email at info@cryocourses.com
NEXT MONTHLY MEETING
The next RRS monthly meeting will be held virtually on Friday, June 10th at 7:30 pm pacific time. Current members will receive an invite via e-mail the week of the meeting. Non-members (or members who have not received recent invites) can request an invitation by sending an email to:
secretary@rrs.org
Please check your spam folders and add secretary@rrs.org to your email whitelist to make sure you are receiving the meeting invitation.
