The RRS held a launch event with the students of Florence Joyner Elementary School at the MTA on April 7th, 2018. This event was the final step in the five-week RRS program that started in February thanks to the support of the Los Angeles Police Department’s (LAPD) Community Safety Partnership (CSP). The students got a tour of the RRS Mojave Test Area where both amateurs and professionals can test rockets in the open space of the Mojave Desert.
As always, we gave a safety briefing to the students to the hazards of the desert and our testing site. Dave Crisalli was our pyro-op for the event and gave an excellent background of the exciting work we do at the RRS.
The tour also included a live demonstration of burning the micrograin zinc/sulfur powders in the open air. The bright yellowish flame is a vivid demonstration of the combustion process.
We also demonstrated the burning of a more common solid propellant, an ammonium perchlorate, HTPB and aluminum powder composite grain. The same constituents used in the Space Shuttle’s solid rocket boosters (SRB’s). Thanks to Larry Hoffing for making the sample grain for the test.
The Flo Jo elementary class built 10 RRS standard alphas for the event. Each painted uniquely by each of the teams.
Once everyone had the safety briefing and completed the tour, we proceed to send everyone to our safety bunker as Dave Crisalli and I loaded each rocket into our rail launcher.
Each of the rockets flew straight and fast from the rails and did not disappoint the class seeing their hard work fly off the rails in a huge yellow cloud.
After the clean launch of all of the rockets, the kids and the LAPD ventured out to the desert to try to find each of their rockets. Flag poles were made for the occasion to mark the locations so that they could be extracted later by shovel. 7 out of 10 rockets were found and two older rockets from previous events were also found and marked. It is tough to find each rocket in the desert scrub, but with the hard work of the students it’s good to recover at least some of the parts as they can be reused with some work.
The kids were very organized and had a great time. After taking a group photo at the gate, they returned to the city. The RRS was glad to host them and hope they can come back soon. Also, thanks to the LAPD CSP program for being supporters of this project to give this experience to the hard-working students of Watts.
The RRS membership stayed behind to try a few experiments. The first test was trying to finish the foot plate welds on the horizontal thrust stand I have made for static testing alpha rockets motors of similar size with S-type load cell donated to the RRS by Interface Force Inc.
Interface Inc. – Precision Load Cells
The construction of the horizontal thrust stand is nearly complete, but unfortunately the desert winds made welding of the plates impossible. This steel frame will firmly hold alpha-sized rockets for static fire testing when bolted down to concrete slab in front of the old blockhouse. As a historical note, it was a young Dave Crisalli that helped pour this slab in the late 1960’s.
Scribe marks were made on the plates and the assembly was taken back to the city to be completed later. Many thanks to Jim Shirley of Shirley Design and Custom Fabrication in Huntington Beach for finishing the structural welds. The integration of the load cell and final mounting to the concrete slab will take place at the next launch event where the RRS hopes to measure the thrust and impulse bit of our standard alpha rockets.
Richard Garcia built his own vertical test frame to support a small steel engine case he made for a rocket-candy grain.
Rocket-candy is a simple mixture of potassium nitrate and sugar. Under moderate heat, the sugar caramelizes to form a viscous but firm mixture that suspends the oxidizer and can be packed in to the paper tube cases.
Richard’s work was documented by RRS member, Alastair Martin, who is working on a larger documentary of the RRS classes and our members’ experimental work at the society.
Once the motor grains had set, they were test fired to verify the quality of the mixture. The second motor grain was loaded in the steel rocket tube mounted to the vertical stand. Results were not spectacular as the end-burner grain design didn’t create much pressure. More testing will be done to improve performance, but the steel case and nozzle were undamaged.
One of the newest tools invented by our president, Osvaldo Tarditti, is a new ratcheting tool that pulls the rocket straight from the ground by a simple portable frame that can be angled to get the rocket to come out straight. The tool must be operated by two people to pull the rocket body straight from the ground. The tool was successfully demonstrated and nine rockets were pulled from the ground without any of the back-breaking work of shoveling. This is an excellent advancement for the society and will be very handy in the future.
As this is the first launch event of this 75th anniversary year of the society those of us that were at the MTA at the end of the day took a group photo by the old I-beam which has been a part of the RRS since our earliest days of rocket testing. You can see the I-beam by itself in many of the old society photos. At the new MTA site, it is an integral part of our larger test structure that has seen hundreds of uses and still going strong.
The RRS will be having their next monthly meeting on Friday, April 13th. The RRS 75th anniversary symposium is also happening on Saturday, April 21st. Please come out as it will be a great occasion with speakers and exhibitors from industry, universities and other amateur rocketry groups.