August 2021 Virtual Meeting


by Keith Yoerg (RRS Secretary)


The latest meeting of the Reaction Research Society took place Friday, August 13th and had 12 attendees who came and went, including a prospective student member. We had a lot of topics to discuss and some members had to leave early so we got right down to society business from the start of the meeting.

Screenshot of discussion during the monthly meeting

YOUTH ROCKETRY CLASS PLANNING & UPDATES

The RRS starting to plan for youth outreach classes – which have been on hold during the COVID-19 pandemic. Unfortunately, due to the delta variant the LAPD classes that were being planned for September at the Strive learning center have been postponed. However, it looks like we are on track to begin classes with the Boyle Heights YMCA after labor day.

This class is expected to have up to 60 students – which will be split into 2 groups that will attend every other Friday at 4pm on a rotating schedule. The current plan is to hold 5 classes per group, which means the program will run for 10 straight weeks. Any RRS member interested in helping during these classes will be required to complete a LiveScan background check. Please contact Frank at vicepresident@rrs.org for more details if interested.

Baby Bertha kit built by RRS Secretary Keith Yoerg

The current plan is for each student to build their own “Baby Bertha” model rocket manufactured by Estes. The EC is currently organizing logistics to allow each student an opportunity to fly their rocket twice (assuming the first launch is successful, of course!) at our MTA site in late October or early November. In addition, we are looking at the instructors building a high power rocket in tandem to show the similarities and differences between the construction methods. A demonstration flight of the high power rocket would be held on the same day as the model rocket flights, to give the kids a sense of what a more powerful flight would look like.

Discussion at the meeting included ideas around fast-drying non-toxic glue options for the model rockets, 3D printed fin alignment jigs to ensure arrow-straight flights of the kits, and logistics around the launch day like adding more low-power launch pad capabilities to the MTA site. We may also try to add an onboard camera to the high power kit to show the students a view of the ground falling away from onboard the rocket!

PERMANENT BATHROOM & OTHER MTA UPGRADES

Progress is continuing on the permanent RRS Bathroom structure. Work on cutting holes for doors and windows has been completed on the 20-foot shipping container and delivery is expected imminently to the new work site at Wilbur’s hangar. The next stages of construction including adding plumbing, fixtures, and the doors and windows.

RRS president Osvaldo informed the membership that he purchased a forklift attachment for the backhoe that is stationed in the Mojave desert – which will be a great help with moving tanks and other heavy items that are often required for liquid rocket tests at the MTA. Members also discussed upgrading the launch structures at the site, including an idea for an adapter to allow Alpha and Beta micrograin rockets to use the same rail system and moving over the large launch tower from the “graveyard” on the northern end of the MTA to a more permanent & upright location.

AUGUST MTA LAUNCH EVENTS

After a short review of the July MTA events (writeups by Dave Nordling can be found here and here), members were briefed on the “long campaign” work that is underway by the University of Michigan rocket club “MASA” this month. While typical events at our desert site last only 1-2 days, this campaign is expected to run for 10 or even 14 days total. The exact length of time that they will be at the site depends on how quickly they are able to meet their objectives.

Some info on the MASA liquid engine that is undergoing testing at the MTA

The ultimate goal of the campaign is to conduct a static, hot fire of their 2,500 lbf (10s total impulse) liquid rocket engine. The engine runs on RP-1 and LOX, and utilizes liquid nitrogen and helium as pressurants. Several RRS members and Pryotechnic Operators have generously volunteered their time on both weekdays and weekends to assist the student team in meeting their goals. A writeup of the events will be posted to this site after the testing.

OSVALDO’S MICROGRAIN ROCKET AVIONICS

RRS president Osvaldo Tarditti provided a show-and-tell of his screw type avionics switch, a very clever way to activate onboard rocket electronics when space is at a premium. This is certainly the case in the RRS Alpha and Beta micrograin rockets – which this switch was designed for. The basic mechanism uses 2 sets of electrically separated nuts with wire leads soldered on, which are epoxied to a bulkhead and affixed to the inside of the rocket’s nosecone.

Osvaldo showing his procedure for soldering a lead onto the nuts

When a screw is inserted – the circuit is completed between the nuts and the attached electronics turn on. With proper placement of the bulkhead and a hole drilled in the nosecone, this screw can be installed from the outside of the rocket just prior to launch.

The switch & bulkhead installed in an Alpha rocket nosecone – note the leads attached to both nuts.

Osvaldo completed the avionics package with a mercury switch and a cheap timing circuit board with multiple programming options. When placed together and activated on the launch pad, the mercury switch is jostled during launch which starts the countdown on the timing circuit board. When pre-programmed with the proper timing delay, the timing board countdown will coincide with the apogee of the rocket’s flight path and deploy a parachute. The hope is that this will allow for a more consistent recovery of Alpha & Beta rockets after launches.

CESARONI TECHNOLOGY / CESARONI AEROSPACE

Late in the meeting we were joined by RRS member and rocketry entrepreneur Anthony Cesaroni, who told members more about his companies and the time he spent at the MTA back in the 90s. With locations in Toronto, Florida, and Spaceport America (New Mexico) Anthony’s companies are major players in munitions, solid rocket motors, and even liquid engine components for Virgin Galactic. Among the major projects underway currently is a full 4-stage orbital vehicle, with hopes of full launches from Wallops and Kennedy Space Center in the 2023/2024 timeframe. Members were very excited welcome Anthony back into the fold and hear about the great work his companies are doing.

RRS WEBSITE UPDATES

The final topic of the evening was regarding updates to this website. The general consensus among members was that it is time for a fresh look and modernization to the website, and there was a robust discussion of the different avenues (and associated prices) that could be pursued. Anyone interested in helping to make this a reality can contact RRS secretary Keith at secretary@rrs.org.

NEXT MONTHLY MEETING

The next RRS monthly meeting will be held virtually on Friday, August 11th 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 receive the invitation.

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MTA launch event, 2021-06-19

by Dave Nordling, Reaction Research Society


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.

president@rrs.org


MTA launch, 2019-12-07

by Dave Nordling, Secretary, Reaction Research Society


The RRS had our last launch event of the year this Saturday, December 7, 2019, at the Mojave Test Area (MTA). We were hosts again to the Los Angeles Police Department (LAPD) Community Safety Partnership (CSP) and this time with 99th Street Elementary.

The RRS has been reworking some of our rails including our trusted and reliable alpha rail launcher. Months of use had slowly built up uneven layering of zinc-sulfide on the rail surfaces making loading difficult but protecting the steel surfaces from the slow corrosion of the dry salt lake bed just a few miles away. Osvaldo did great work in giving our alpha rail launcher a new lease on life. Thanks also to Russell Hoffing and his kids for helping out with the installation before the event crew arrived.

The refurbished alpha rail launcher is being re-installed on its concrete pad before the 12-07-2019 launch event at the MTA.

The winter seasonal rains have arrived a little early to southern California, but the weather began to clear today just before we started. The winds were very low which was excellent for launching rockets. From the washing action of the rain this week, the loose sand drifted into a vein-like pattern over the harder sand below which gave the ground a slightly “Martian” quality. It was cool but not cold and a great day for a launch.

The 8-inch adjustable rail launcher is still under repair from the failed July 2019 launch. The inner adjustable rail slides are being built from scratch. One of the outer braces was blown off and some of the angle frame pieces are distorted. This will require a lot of rework but we hope to have this launcher back in service soon.

We had a minor problem from the rainwater gathering in the bunker. It wasn’t more than an inch or two deep, but on a cool December morning, it would be a miserable place for our guests. The RRS was grateful to some of the Friends of Amateur Rocketry who let us borrow a small sump pump to pull the standing water out.

Frank Miuccio mans a simple broom to sweep the water towards the small sump pump in the corner. The RRS thanks our neighbors at the Friends of Amateur Rocketry site for their assistance.

We gave the students the standard safety briefing about how to avoid the dangers at the site. We also gave them a live demonstration of how the micrograin zinc and sulfur powder burns in the open showing the brilliant yellow color. Larry Hoffing had also prepared a small sample of solid composite propellant made with ammonium perchlorate and an iron oxide accelerant.

A sample of micrograin propellant lights in a metal cup to show how two simple pure substances can burn so energetically.

Larry Hoffing and his grandsons had a few model rockets to try out at the event. After setting up the launch wire and clamping the smaller 6-foot long 1010 rail to a suitable rigid and weighted base. Winds were very light all day so we had few problems from the elements.

Larry Hoffing and his assistants posing before starting the launch of a few small model rocket motors. The RRS MTA is for rockets of all sizes.

Larry flew a classic Estes model, Big Bertha, which is always a crowd-pleaser. This vintage model design is slowly powered at take-off by a C6-3 commercial motor then gains traction after its fins start working. It has flown to couple hundred feed then at apogee made a nice parachute recovery.

The high-powered fiberglass bodied rocket launched on a 1010 C-rail was boosted by a vintage Flight Systems F6-7 motor, but failed to move vertically up the rail by more than a couple of feet before settling nicely on the launch pad with an impressive 6-inch exhaust flame. It will be back to the drawing board for that model with the possible addition of a more powerful G-sized AP motor or a H-sized hybrid. The students at 99th Street Elementary witnessed the launch, but the biggest part of the event was yet to begin.

Osvaldo holds the finished product, a loaded RRS standard alpha with micrograin propellant. Note the painter’s tape covering the four mounting bolt holes which also minimizes spillage.

The ten RRS standard alpha rockets from the students were already loaded the night before. A last minute addition of another alpha painted by their teacher was included. Osvaldo showed me his latest propellant loading approach that minimizes external powder contamination on the person loading. Using zinc-sulfur is simple, but it has it’s own problems. Many of our spouses and friends are not pleased with the persistent odor of brimstone (raw sulfur) on our clothes upon our return to the city. Osvaldo has known this problem for years and found a simple method of blocking the migrating propellant dust using a simple pillowcase shield. He has also improved the mating funnel and with a steady light bouncing of the propellant tube on a wood block, the propellant tube can be filled with its 3.2 pounds of zinc-sulfur mixture.

Our alpha launch operations were conducted a little differently at this event. Osvaldo did the loading at the rails, while I was manning the launch switch in our observation bunker with everyone else safely under cover. By California law, the person on the launch switch is the pyro-op in charge. With our experienced team doing road and air space checks before each firing, we had a good safe launch and a lot of fun.

Dave Nordling in the bunker waiting for the first alpha to be loaded. Note that nothing is connected until all is loaded and ready.
Osvaldo Tarditti loads an alpha into the rails in preparation for launch.

We had ten alpha rockets plus one extra painted by the teacher for this event. All of them looked really sharp with bright colors easy to spot when recovered from the desert floor. 99th Street Elementary really enjoyed the five weekly classes and were very exciting to have the last class at the Mojave Test Area to see real demonstrations of rocket propellants and the micrograin powder in each of the rockets propelling them into the gray sky one by one.

Ten plus one alphas from 99th Street Elementary loaded and in wait for their time on the launch pad.

Most of the alpha flights were perfect. The flight times were consistent and given the low winds we could hear the whooshing return and the thump on nearly every one to confirm impact.

A nice clean launch of an RRS alpha at the 12-07-2019 event.

We had one particularly troublesome flight which is a rarity with the RRS standard alpha after all of the years spent perfecting that design. The second rocket sputtered and hesitated a lot before taking off slowly from and rails and flopping back to the ground. No obvious cause was found on that rocket, no unusual burn pattern or melting and the propellant tube seemed intact. After inspecting the rocket more thoroughly upon its recovery just a few feet from the launch rail, it was clear that the nozzle mounting screws must not have been installed. No damage was seen to either the propellant tube or the nozzle. The nozzle throat was in tact which indicates it must not have been present to choke the fiery exhaust flow. This also explains the profound lack of thrust, but yet even without a nozzle the micrograin rocket was able to generate enough pressure to lift itself out of the rails. The nozzles often fit very tightly into the propellant tubes which might have been how someone could have failed to notice the missing attachment screws during transport to the launch pad. This is quite an error which will not be repeated.

Anomalous launch of an alpha at the 12-07-2019 event.

We said goodbye to our visitors and prepared to clean up the site. In the winter months, the sun sets quickly so we didn’t have a lot of time to search for the alphas. Frank had a lot of luck finding six of the eleven launched that day. Some of the parts can be reused with a little work.

The Tarditti rocket extractor tool, don’t go downrange without one.
An alpha rocket buried up to its fins in the desert floor.

We’ll surely discuss the results of the launch event at the next RRS monthly meeting which is next Friday, December 13th. Also, we’re already planning the next MTA launch event which will happen in January. We are expecting more launches in this next year, 2020. Thanks for reading!