MTA launch event, 2018-06-07

The RRS held another smaller launch event at our private testing facility (MTA) in the Mojave desert on Thursday, June 7, 2018. This was a special event for the RRS members from the former Chaminade High School Rocketry group led by Jack Oswald. They have been working hard on their solid motor design. After a successful test series on a single 6-inch Bates grain, they moved up to a vehicle sized test with multiple six-inch grain modules installed. Dave Crisalli and Osvaldo Tarditti were available to assist in the loading and installation process making ready for testing. The vehicle static fire test was oriented nozzle up with a load cell at the bottom of the frame secured to the vertical test stand at the RRS MTA.

The static fire testing was for a 10,000 lbf-sec flight motor. The motor was expected to perform at 1500 psi, produce over 2+ tons (>4000 lbf) of peak thrust, and burn its 43 lbs of composite BATES grains in approximately 3 seconds.

Osvaldo had video of the firing where we got the still photos below. Osvaldo will bring the video footage to the meeting tomorrow on Friday, 6/8/2018, where everyone can see what may have happened.

Vertical static fire of a solid rocket motor at the RRS MTA, 06-07-2018

The solid motor started okay. The nozzle plume looked good for the first few moments.

Jack’s motor starts off just fine. A nice nozzle plume is evident.

Unfortunately, shortly after start, about 2 seconds into the burn, the pressure climbed substantially to 2300 psi causing a nozzle failure and subsequent burnout.

It looked like something disturbed the flow in the frame just before the huge fireball and the disintegration of the nozzle

After the nozzle failure, the solid motor spews chunks of fiery propellant until it fully burned out.

In the coming months, Jack’s team will make another motor reducing the Kn factor and significantly reinforcing the nozzle design to carry through with their plans of launching a boosted dart to an altitude of 150,000 feet sometime this year. This is still an impressive accomplishment and with some perseverance, success will come. More details to come as things proceed.

During the June 7th event, Osvaldo took some time to search down-range for rockets with his extractor tool. As luck would have it, he found one of the RRS standard beta rockets launched by UCLA in 2017. It was found about 3000 feet downrange which isn’t terribly far away. The winds must have been very favorable to allow the beta to plant itself much closer to the launch site. From the photo, you can see that this RRS beta had a fin-can type of fixture at the tail which is easier to manufacture.

Beta planted 3000 feet downrange from the launch rails, straight west more or less

The convenience of pulling the rocket straight from the ground with the manual winch is tremendous, but the method often shears off the payload tube in the hole. Shoveling does have the advantage of removing most if not all of the parts if one is inclined to spend the hours necessary to dig four feet below the surface. The payload tube from the beta unfortunately was not extracted with the propellant tube. Osvaldo will bring the beta to show everyone at the meeting tomorrow.

Osvaldo lifts the beta rocket from out of the desert floor

We’ll have our monthly meeting (every 2nd Friday of the month) on June 8th at 7:30PM sharp. Please stop in!

MTA launch event, 2018-06-02

The RRS held a launch event at our private Mojave Test Area (MTA) with the students and staff of UCLA on Saturday, June 2, 2018. The event was overseen by our pyro-op, Jim Gross, with me serving as his apprentice. It was a good day for rocket launching despite the 100 degree temperatures that day. The winds were very low and almost still at certain times.

The horizontal thrust stand was fit checked at the RRS MTA concrete slab. All footplate holes aligned with the 1/2″-13 female anchor bolt holes. The load cell blocks mated up to the adapter plates. Concern was raised about the horizontal stability “wagging” of an alpha rocket if it were fired in the adapter as is. Osvaldo started a design to create an extension on the thrust stand which will better retain the rocket from excessive side loading.

RRS horizontal thrust stand passes fit check at the MTA, new primer coating added for rust protection

UCLA was completing a quarterly course in rocketry which featured the hard work of five student teams building their own amateur rocket using commercial F-class motors of different types.

UCLA students pose at the RRS MTA on June 2, 2018

The RRS was able to inspect each one of these model rockets and ask questions of the team members about its construction and the unique aspects used in their payload and vehicle design. Each of the teams ran flight stability tests at the UCLA wind tunnel to validate their design. Each rocket was fired from a rail launcher and a commercial firing circuit under the supervision of the pyro-op.

Six rockets from five teams at UCLA on display in the group photo (6/2/2018)

Before the flights of the student rockets, a test rocket was flown to check the wind speeds. Results showed low winds so the team flights proceeded. The winds at the launch site in the desert were very low throughout most of the day.

UCLA’s demo rocket to test winds before team flights.

UCLA prepares their custom rail launcher for their model rockets

One team attempted a two-stage rocket using a D-class motor in Stage 2. Results from all rockets were largely good. All were recovered and some were able to be relaunched.

UCLA’s Team Sharky prepare their rocket “Bruce” for his maiden voyage.

Each rocket flew an egg as a payload with a parachute recovery system. Each rocket also included a commercial altimeter chip which relayed the results to display on a cellphone application. Altitudes ranged from 1600 to 2400 feet.

UCLA also was static testing a hybrid motor adapted from commercial products to a design of their own. Two vehicle systems were built and alternately tested with replaceable HTPB-based fuel grain modules. UCLA brought a few nitrous oxide tanks to replenish their oxidizer supply. All seemed to go well, but the results were not good enough to proceed with a flight test as originally scheduled.

Dr. Mitchell Spearrin and Jim Gross oversee the hybrid rocket static firing procedure at the RRS MTA, 6/2/2018

UCLA’s Anil Nair prepares the hybrid motor for static firing at the RRS MTA, 6/2/2018

UCLA’s first of three hybrid motor firings, 06-02-2018

Results from first hybrid motor firing left a white residue around the outside of the nozzle

UCLA did buy two of our RRS standard alpha rockets which were custom painted in the blue and gold colors of the UCLA Bruins. At the end of the long day, UCLA opted not to fly their two RRS standard alphas and save them for another flight. The RRS and UCLA discussed flying an altimeter chip in a vented payload tube on the next UCLA flight of the RRS alpha.

Two RRS standard alpha rockets for UCLA

The RRS already had the micrograin propellant mixture ready so we proceeded with a flight test of our own RRS alpha rocket. We had plenty of daylight left in the summer month of June. For those that stayed at the MTA into the late afternoon, the RRS did conduct a first test of a payload recovery system in a standard RRS alpha rocket. This system was built by RRS president, Osvaldo Tarditti.

Jim Gross and Osvaldo Tarditti load an RRS standard alpha with parachute payload into the launch rails

An RRS alpha with its payload being installed.

Instrumented RRS alpha in the launch rack. A manual switch with red flag is used to arm the system before launch. This keeps the battery from depleting while waiting to launch.

The payload timer is started when the rocket lifts out of the launch rails and the pin is pulled out by the yellow wire tied off to the launch rails.

Despite some problems initializing the payload one the first attempt at the launch rack, the rocket was successfully reset, reloaded and flown. The deployment of a parachute from inside an RRS standard alpha rocket’s payload tube with a successful recovery was the only objective of this flight.

In the still winds, the rocket didn’t drift very far from due west and the orange parachute was very visible against the clear blue afternoon skies once it reached lower altitudes. The alpha rocket booster portion was recovered, but the lanyard holding the nosecone and payload segment tore loose on deployment and was not recovered.

Lanyard failure lost the payload and nose with the timer circuit inside, 6/2/2018

Also, the orange parachute did show signs of localized overheating and melting from the 1-gram black powder ejection charge used to deploy the parachute.

scorching of the parachute from the ejection charge; parachute was still effective

The parachute did deploy fully and significantly slowed the descent of the rocket booster. With the low winds, the rocket did not drift very far downrange and was easily recovered 50 feet from the roadside going out west from the MTA

Osvaldo kneels behind his RRS standard alpha parachute system successfully flown at the MTA on 6/2/2018

I took several photos of the assembly and loading process. Osvaldo has promised to explain the full details of his parachute system and deployment timer. The RRS will definitely reattempt parachute recovery with our alphas and hope to fly again at the next event.

As a final step, we make sure to burn off our residual propellants. Jim Gross set this up near the launch pad and used the firing system already in place at the bunker.

Pyro-op Jim Gross prepares to safely dispose of residual micrograin propellant at the RRS MTA

Residual micrograin propellant safely burns up at the end of the day

At the end of the propellant burn-off, the smoke cloud lazily lingered as it rose away from the site. Taking several minutes to do so, this was a very visual reminder of just how favorable the winds were that day.

minutes later, a spent micrograin propellant smoke cloud slowly drifts away in the low winds at the MTA

If there is anything I have missed or misstated, please let me know.
secretary@rrs.org

The next monthly meeting is this Friday, June 8th at 7:30PM. Discussion of the UCLA event and our next event with LAPD CSP will certainly be on the agenda.

MTA launch event, 2018-04-07

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.

Students from Flo Jo Elementary at the RRS MTA

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.

Dave Crisalli addresses the students and officers as Frank Miuccio looks on

Safety briefing inside of the George Dosa building at the RRS MTA

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.

Live demonstration of micrograin propellant at the MTA

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.

Sample of a composite solid propellant grain just before the demonstration.

The Flo Jo elementary class built 10 RRS standard alphas for the event. Each painted uniquely by each of the teams.

Standard alpha rockets from Flo Jo Elementary

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.

Dave Crisalli and Dave Nordling load an alpha into the launching rack

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.

wide-angle still shot from Osvaldo’s high-speed camera, 2018-04-07

An RRS alpha rocket takes off, view from the bunker

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.

After launch, the students and their mentors march to the desert to search for their rockets

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.

Flo Jo Elementary and LAPD CSP pose before the RRS MTA sign

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.

Osvaldo prepares to weld the foot plates of the horizontal thrust frame at the MTA

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.

The RRS horizontal thrust stand frame is complete and ready for mounting at the MTA

Richard Garcia built his own vertical test frame to support a small steel engine case he made for a rocket-candy grain.

Richard mounts his frame to the MTA structure for his experiment.

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 “cooks” the sugar and potassium nitrate under low heat of the electric hot plate.

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.

Alastair Martin films the tools and process of Richard Garcia’s rocket candy production

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.

Richard Garcia’s steel motor case and nozzle, just before loading the motor grain

Richard’s sugar rocket motor fires securely from the vertical mounted stand

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.

Osvaldo’s newest invention, the Rockextractor

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.

Frank Miuccio, Alastair Martin, Dave Nordling, Richard Garcia and Osvaldo Tarditti pose by the iconic RRS I-beam

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.