Category Archives: Firing Report

MTA launch, 2019-12-07

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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!

MTA launch event, 2019-09-21

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Larry Hoffing, Events Coordinator, RRS

Photo credits: Osvaldo Tarditti

The Reaction Research Society held another launch event with the LAPD CSP. This event was with the students of Boyle Heights. We had ten standard alphas launched into the blue Mojave sky that day including some model rockets made by Russell Hoffing and my grandson.

A lot of different groups came out for this launch event at the RRS MTA, 09-21-2019

We had students from the CSU Long Beach liquid rocket team come out to make some measurements for sub-system testing that they are planning at the RRS MTA this year.

CSU Long Beach inspects the vertical mounting structure at the RRS MTA
Model rockets in the George Dosa building undergoing preparation for launch
Students from Boyle Heights get their orientation instructions at the RRS MTA
RRS events coordinator, Larry Hoffing; RRS VP, Frank Miuccio and RRS president, Osvaldo Tarditi

Returning RRS member, John Krell, had worked up two prototype instrumentation packages for flights in the ninth and tenth RRS standard alphas on that day. Both rockets were recovered and the results were impressive.

John Krell arms his payload integrated into one of two RRS standard alphas, 09-21-2019
One of John’s prototypes survived the flight and is laid out on the table in the Dosa Bldg.
John Krell examines the recovered SD memory chips to determine the flight profile from the RRS alpha. Over 100 G’s of acceleration at take-off max’d out the sensor!

Materials have been acquired to repair the adjustable rail launcher that was damaged in early August this year. Osvaldo has been busy at work on the repairs. The RRS has several facility improvement projects in the works and we hope to bring this rail launcher back to service soon for larger rockets (4 to 6 inches).

John will hopefully have a full report and an overview of his design. Both Bill Behenna and Brian Johnson are also working on their own instrumentation designs for the RRS standard alpha. With this recent progress, this should help our others members take better data.

Still photo from RRS alpha #3 of 10 launched at the MTA on 09-21-2019.

We’ll discuss more of the results of this event in detail at the next RRS meeting on October 11, 2019. The RRS meets every 2nd Friday at the Ken Nakaoka Community Center in Gardena, California. Stop in and see how things went.

MTA launch event, 2019-07-13

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by Dave Nordling, Secretary, RRS.ORG

The RRS was glad to have another launch event at our Mojave Test Area (MTA) on Saturday, July 13th. Our event this time was with Operation Progress in Watts. Thanks to our partnership with the LAPD CSP, we are able to fly nine alphas and a beta rocket at this event. It was to be a typically hot July day in the Mojave, but the winds were still through the morning picking up a little as the afternoon went on.

The RRS thrust stand structure flying Old Glory with the nine alphas (left) and the larger beta rocket (right) waiting for launch.

This was my first time as the event pyro-op. New member, Kent Schwitkis of Compton College and Waldo Stakes assisted me with the operations as we gave our young rocketeers a great view of their hard work.

Waldo Stakes in the old blockhouse as we prepare for firing of the next alpha rocket from the box rails.

As the LAPD CSP arrived at the RRS MTA, the society prepared to give a site tour to the students followed by our safety briefing.

The students of Operation Progress take some shelter and hydrate under the cover of the George Dosa building.

Our sample propellant burn demonstration gave the students a visual indication of what would be to come with the propellant driving their custom painted rockets into the blue sky. With the briefing and demonstrations complete, the students took shelter in the observation bunker.

RRS members, Kent Schwitkis and Dave Nordling loading an alpha for Operation Progress

One of the interesting features I noticed with this set of alphas was the use of modelling clay at the nozzle to hold back the micrograin propellant. This proved to be an equally effective method of holding back the propellant when the rocket is in firing position as the typical phenolic thin disks we commonly use.

The electric match lead wires emerging from a wad of modelling clay used to hold back the micrograin powdered propellant. The hole seen in this photo was smoothed over by a gentle brush of the finger. The method proved to be very effective.
A close-up view of the alpha nozzle with its plastic burst-disk and electric match resting on the interior side, the electric match wires protrude out the bottom (held back by carpenter’s tape just for convenience)
Kent holding the second to last alpha in the set. This one has a special feature added on the fin. A whistle.
An alpha streaks away almost perfectly straight in the nearly still winds.

One of the alpha rockets was outfitted with a whistle on one of its fin. Although imparting a spin during flight, the alphas tend to remain somewhat stable in flight. The results from this flight was somewhat disappointing as the whistle could not be clearly heard in either ascent or descent before impact.

Whistle attached to the fin of an RRS standard alpha to provide an audible trace of its flight

Our last rocket for Compton College was the larger RRS standard beta rocket. This two-inch diameter powerful vehicle made its impressive mark on the launch pad as it tore into the sky. After the launch, we took break for lunch. With the day growing hotter by the hour, our partners with the LAPD CSP and Operation Progress bid the MTA and the RRS farewell as they returned to the city.

Still capture of the beta flight from Frank Miuccio’s cell phone video footage from the bunker.

Following lunch, our second group at the event was a team from Compton College made up of Prof. Kent Schwitkis and Brian Johnson and their students. The Compton Comet was a standard alpha rocket outfitted with an instrumentation package and a parachute.

RRS welcomes Compton College at the MTA
The team discusses the assembly and operation of the payload in the Compton Comet.

New RRS member, Professor Kent Schwitkis got his first experience with loading the micrograin propellant in the Compton Comet at our loading area. This is a rite of passage for many of our new members. Although old and grossly inefficient, the zinc and sulfur powder propellant combination offers a simple and powerful combination to lift rockets in a yellow rushing plume.

After loading the propellant tube, the team begins their final assembly by mating the payload to the coupler.
The Compton Comet nearly complete with one more joint to connect.

The Compton Comet was loaded by the team into the alpha launch rails. All of us retreated to the concrete bunker for firing.

The team puts their hands on the rocket one last time before going to the pad.
Loading the Compton Comet into the RRS alpha launch rails. The payload arming flag flowing in the breeze.

The Compton Comet parachute somehow failed to deploy. The ballistic return of the rocket meant extraction by the time-honored method of shoveling. The Compton College team showed tremendous fortitude in the scorching 110 degree weather. The fruits of their labor was the return of the instrumented payload including the data chip inside.

Recovery of the Compton Comet by shovel.

Initial results showed that data was taken throughout the flight. The results are being reviewed by Compton College to be reported later to the society.

This was a very successful launch day at the RRS MTA and the society was glad to support the Operation Progress and Compton College student teams at our Mojave Test Area. For more information on similar rocket building programs with the RRS, contact our events coordinator, Larry Hoffing.

events@rrs.org

For all inquiries about using the RRS MTA, contact the RRS president, Osvaldo Tarditti

president@rrs.org