Tag Archives: wireless launch controllers

MTA launch event, 2021-03-20

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Dave Nordling, Reaction Research Society

The RRS held a launch event at our Mojave Test Area (MTA) on March 20, 2021, the spring equinox. COVID-19 still remains a threat so everyone had to observe protective protocols. We had a lot of wind that day making launch impractical, but we still were able to get many things done that day including another static fire of a hybrid motor, some system checkouts of the Gas Guzzler and a possible flight of the Solar Cat steam rocket. Osvaldo Tarditti was our pyrotechnic operator in charge. Also joining us that day was fellow Rockets 2nd Class pyrotechnic operator and RRS member, Jim Gross,

MOBILE TRAILER CLEANUP

Mike Gottlieb was a lifetime member of the RRS who passed away over 2 years ago. Years prior, he had acquired a surplus mobile trailer from the former Rockwell International company which was left to reside at the RRS MTA. By permission from his surviving family, this single-axle, climate controlled trailer has been donated to the society. The trailer was opened by the RRS president and the interior inspected by our members present at our March 2021 launch event.

The Rockwell mobile trailer at the RRS MTA
The interior needs a little work but otherwise has a lot of promise.
A spacious interior which could be used as an office space.

For now, the space will be used for light storage until more space can be acquired elsewhere. We used the time to reorganize the contents of our storage trailer. We hope to renovate this new mobile trailer soon and restore its climate control systems which will be convenient in the summer months.

PUBLIC ADDRESS SYSTEM AT THE MTA

During the cleaning and reorganization of our storage space, we pulled out the public address equipment we had. The 12 VDC battery powered system including loud speaker and microphones worked well in a test from the old blockhouse. The society has talked about having a more distributed system around the main areas of the site. This will require some further equipment purchases, but for now we have a core system to start from. The goal is to make coordination of our events easier to do when we have large groups of people at the MTA again. Further still, we’d like to coordinate launch timing better with our neighboring amateur rocketry group (FAR) to our south.

Keith Yoerg holds up the speaker after a successful test at the old blockhouse

NEW RESTROOM FACILITY

As discussed at the March 2021 monthly meeting, the society is going forward with building a new restroom facility with flushing toilets. This will be a big convenience to our visitors and members alike. The executive council has received bids and plans for the restroom and is working with suppliers to find the best solution given our budget. We are grateful to our generous benefactor and the many people who supported this project with their time and skills. More progress should be made soon as we would like to deploy this facility before the hot summer months arrive this year.

General placement of the proposed new restroom facility at the MTA subject to change and only for illustration..

FIRST FLIGHT OF THE SOLAR CAT FROM THE MTA

Bill Inman and new member Jonathan Wells returned to the MTA for another attempt to launch the solar powered steam rocket, the Solar Cat. He has been making many adjustments and had his first launch near his home in Carson City. Today would be his first launch of his Solar Cat from the MTA.

Bill Inman and his team set up his parabolic solar heating system for today’s sunny day at the MTA

Bill was able to work out minor problems on his trailer mounted systems last month and was fully ready to use his solar heating and tracking system for the hours necessary to reach launching temperatures of the stored water load in his steam rocket.

Bill has had some minor problems with the release system which led to a unintended release of the rocket. No one was injured but it did cost him several useful hours for insolation (heating). His second attempt was only a partial heat load but sufficient to conduct the first (technically second) flight at the MTA. Keith Yoerg managed to capture the short flight in the late afternoon. It’s a bit comical to watch given how short the flight was, but it is a significant milestone in getting this non-traditional form of liquid propulsion to work. We look forward to the advancements, Bill will make for future flights from the MTA.

The Solar Cat gets a clean release from the launcher and clears the rails on 3/20/2021.
The Solar Cat reaches its apogee while still in the frame of the video recording.
The wind pushes the rocket back to the launcher for an ungraceful return then clonking to the ground.

REBUILD AND SYSTEMS CHECK OF THE GAS GUZZLER

Wolfram Blume had made several improvements since his last flight attempt of his two-stage ramjet-solid motor rocket. He was able to correct software issues but also made physical feature changes to his booster. Wind speeds were excessive for much of the day, so he used his time at the MTA for fit checks while on the 1515 rail launcher.

Osvaldo Tarditti and Bill Janczewski observe Wolfram Blume’s operations with his ramjet upper stage in our loading area. No gasoline will be used in the maiden flight which will test the booster and staging systems. The unique design will need some flight testing before committing to a full flight with a fueled upper stage,
Wolfram Blume walks to the launch pad where his Gas Guzzler rocket rests on the pad.

Wolfram was able to conduct his tests making use of the 1515 rail launcher. He left in the afternoon after completing his tests and will return for our next launch event planned for April 10. 2021.

WIRELESS FIRE CONTROL AT THE MTA

Wireless fire control is a remote means of conducting launch without stringing long wire connections. This has been a controversial subject at the RRS with some of our members actively supporting using these systems and others being skeptical about their safety.

Richard Dierking mentioned the Wilson F/X wireless firing system which has been used at the Rocketry Organization of California (ROC) and at the Friends of Amateur Rocketry (FAR) site. Fellow RRS member, Dmitri Timohovich, has used Cobra Firing Systems for pyrotechnic events in the movie business with success. He brought one of these systems to demonstrate at the MTA with test bulbs. The 64-bit encryption in this system vastly reduces the possibility of stray signals causing an unintended firing.

Two 18-channel fire control boxes with the remote in the middle.

A decision was made at the March 2021 meeting to proceed with care by testing one of these wireless fire control systems with only low-power simple model rockets. We also thought meeting with a sales representative or technical advisor from a wireless fire control system manufacturer to explain the safety of these systems to the society would be an excellent idea. Some of our members have had a negative experience with these systems with unintentionally firing. Older wireless fire control systems have had safety issues. Safety in operations with pyrotechnics of any kind is of paramount importance.

wilsonfx.com

cobrafiringsystems.com

The RRS plans to educate themselves further about wireless firing system technology before making any further policy decisions. It is agreed that every pyro-op in charge at the event has the final say about what systems are and are not allowed at the event. The best course of action for any project leader is to discuss all aspects of their test or launch with the pyro-op in charge well in advance of the event at the MTA.

STATIC FIRING OF THE HYBRID MOTOR

The last two firings of the Contrails H222 38mm 16-inch hybrid motor left some questions about how reliable the ignition of the motor is. From both prior flights, it was evident that quick severance of the nylon plastic fill line at the launch command was not happening. Altitude was very low from such a powerful motor according to the curve. Since the last flight damaged the rocket body beyond repair, the next firing was intended to watch the startup sequence in careful detail under static conditions.

The motor survived in tact from the last short flight, The nozzle, spent grain and floating injector were shoved forward from the impact, but all parts were able to be removed, cleaned and reassembled for another firing with the last of my three fuel grains from the kit.

.The Contrails H222 motor reloaded for the third time.

The static test firing was done on the vertical test stand using a simple wooden fixture and 1/2-inch fasteners. The fixture was built quickly and unfortunately not perfectly. We had to fire the motor upside-down which is not representative of how the engine flies.

The vertical test stand holds the hybrid motor ready for firing with the fill line above and clear vent line below.
The 3/16” nylon fill line c0nnects to the floating injector push to connect fitting below the fuel grain and graphite nozzle held down by the snap-ring. The electric match is wrapped along side of and held against the fill line.
Acrylic 1/8” vent line from the top bulkhead push to connect fitting

The igniter used in the 3-20-2021 test used an electric match as was done in the second test. The kit comes with an electric resistor. In the first test, this was insufficient to get ignition and sever the fill line. Second firing used an electric match and a fragment of composite propellant. This achieved ignition but the fill line wasn’t fully severed. The third attempt used a similar load with a bit more composite propellant. The idea was to produce an ignition flame hot and fast enough to soften and sever the pressurized nylon fill line, With the escaping oxidizer liquid, the combustion should be enhanced and help sever the line. In practice, this doesn’t seem to occur quickly enough,

In the hybrid firing that day, the igniter fired and some chuffing from the nozzle was seen but the combustion was not sustained and the oxidizer supply emptied. The motor will be disassembled and inspected to see if all the composite propellant was consumed or if the nitrous oxide dispersed the pack before the full burn could finish.

A thin piece of composite propellant pressed against the electric match head pressed against the nylon fill line.
Floating injector loaded with the igniter and fill line strung through the fuel grain and nozzle.
The hybrid firing box with ruggedized 100-foot cable

The new hybrid rocket firing box with built-in solenoid valve and fire control.

MORE WATER ROCKETS

Dmitri upgraded his water rocket launch system to fire multiple rockets. He had a remote firing box which made it very easy to set up. The winds were too strong for any high altitude flights, but the modest water rockets were plenty of fun.

Water rockets lift off from the new blockhouse.

MODEL ROCKETS

The Yoerg Challenge started as a simple request to those attending our meeting on March 12, 2021 before the launch event: build as many model rockets from as many people as possible and launch them from the multi-wire launcher array that Keith built last month. Dmitri and I both answered the challenge for the event, Although many of our members have built many model rockets since they were kids, some of have not. For those experienced and inexperienced, the Yoerg Challenge was issued. More rockets at each successive event inspires others to build more rockets and more ambitious rocket builds. The RRS is for all forms of reaction propulsion even with a simple model kit.

The Estes Generoc E2X loaded with a C6-7 motor. An inexpensive and simple answer to the Yoerg Challenge,
Dmitri Timohovich built the Firestreak SST for the Yoerg Challenge
A few model rockets fly up and away at our arch.

At the end of the day, Keith and Dmitri launched their model rockets using small “A” sized motors to keep their altitudes low and avoid being carried far downrange with the high winds. I decided not to fly my first model as I left early that day. We hope others will build and bring theirs at our next event.

IN CONCLUSION

Next launch event will be April 10, 2021, with USC and member projects.

March 2021 Virtual Meeting

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by Keith Yoerg (RRS Secretary)

The latest meeting of the Reaction Research Society took place this past Friday, March 12th and had 20 attendees (who came & went at different times) – including a guest presenter. Society president Osvaldo began discussion by informing the group that USC has requested a launch of their 6″ booster rocket in April, before leaving the meeting to go on a Home Depot supply run.

Screenshot of discussion during the monthly meeting

GUEST PRESENTATION – GEORGIA TECH YELLOW JACKET SPACE PROGRAM

Sam Kim from the Georgia Tech Yellow Jacket Space Program made a presentation on their mission to be the first collegiate team to send a liquid rocket to Karman Line. The team conducted the first hot fire of an 800 pound-force LOX-kerosene engine in November 2019 (pictured below). This engine will support a sub-scale rocket which will be used to prove and test methods on this student-designed, -machined, and -assembled project.

November 2019 static fire of the Georgia Tech YJ-1S rocket

The team has planned a launch for the sub-scale rocket in October to an apogee of 5,000 ft. An 11-second burn static fire of this engine is expected in April. The team conducts testing out of the DeKalb-Peachtree Airport, and plans to make launches from the Spaceport Camden in southeast Georgia.

BILL CLAYBAUGH’S 6″ ROCKET

Bill Claybaugh presented a number of hardware pieces related to a 6″ rocket which he hopes to launch this year. The rocket will fly on a 6″-diameter, 60″-long motor producing 1,350 lbf of thrust with an 8.3-second burn time. This design is optimized to be used as the second stage in a rocket boosted by a 9″-diameter motor, but the impending flight is only the 6″ second stage. Bill mentioned that he has a test flight planed for the 9″ first stage some time within the next year. The combined 2-stage rocket will have to fly out of a national range because of the expected altitude of 120 statute miles.

Bill showing off the avionics package on his rocket

The hardware that Bill C. presented from his rocket included the tapered fins, bulkhead assemblies, and a section of the 40″ avionics payload which will be mostly contained within the nosecone. In addition, Bill provided insight on the FAA paperwork that he is currently completing for the flight of the 6″ rocket. The FAA form 7711-2 he has been working on is the same one used for airshows, and requires a supplemental that covers both class 2 & 3 amateur rockets. The final hurdle is the “splash pattern” Monte Carlo analysis of over 1,000 launches with varying launch angles, wind, and other launch parameters to determine the probability of landing in a populated area. He expects the launch will be deemed safe, and plans to submit the paperwork soon.

PLANS FOR THE UPCOMING MTA EVENT – SAT. MAR 20

Several members stated their intentions to join the launch & work event at the MTA site next Saturday, March 20th. Work on welding the new plate on the vertical test stand, clearing brush in the launch/firing areas, and other site maintenance may take place if time and equipment availability allow. There has also been discussion of taking an inventory of the working order of some Society equipment (such as the PA system) stored at the site.

Bill Inman plans to once again bring out his solar-powered steam rocket, Solar Cat, which uses mirrors to heat water with sunlight. Bill has been a fixture at MTA events the past several months, perfecting the design and procedures so that he won’t be caught unable to launch because of a minor oversight like untested equipment or cables that are too short. Although all of his equipment is flight-ready, MTA launches are always at the mercy of the Mojave desert weather. Wind, rain, and sunlight permitting – we hope to see the Solar Cat take to the skies next weekend!

Early stages of Dimitri’s water bottle rocket module, which is now assembled & ready for testing

Wolfram Blume is vaccinated (an impediment to his attendance at last month’s event) and ready for another launch attempt of the booster stage on his rocket, Gas Guzzler. In the final version the upper stage will include a gas-powered ramjet, but this flight will be flown with water instead. The goal of this test is to measure drag & acceleration, particularly during separation of the booster stage, which will help inform the final design parameters. We’re excited to see this launch, and expect it will be a fun one to watch!

Keith Yoerg will bring his model rockets and multi-pad wire rail launcher to test out deployment boxes and high-power solid rockets to test LoRa GPS trackers as a cheap rocket tracker. Dimitri is finishing work on a his hybrid & water rocket launch controllers (pictured above), both of which should be ready for testing on Saturday as well. It was once again agreed that a grill-out should take place, which is quickly becoming an MTA event tradition.

WIRELESS LAUNCH CONTROLLERS

The last topic stimulated a great discussion on the use of wireless launch controllers, with many members providing thoughts and opinions. Richard Dierking presented the commercially available Wilson F/X wireless control box, which consists of the firing box shown in the photo below and 2 wireless modules which run on 12V gel cell batteries. This entire system cost him around $900, and larger versions of this system have been used by the Rocketry Organization of California (ROC) and Friends of Amateur Rocketry (FAR) for launches of high-power solid rockets.

Richard Dierking showing a Wilson F/X wireless control box

Dimitri expressed his comfort and trust in the Cobra wireless firing system, which he has used many times as the Pyro Op for million-dollar shots in movies and television. The Cobra system uses 64-bit encryption (it was suggested that the Wilson F/X system uses 32-bit) and the only issues Dimitri reported was when attempting to fire directly near an ultra high-speed camera. Richard stated that he would look into getting someone from the Wilson F/X company to attend a future RRS meeting to describe that system in further detail.

Most members expressed cautious optimism about the potential of using wireless launch controllers at RRS events, though it was re-iterated that the Pyro Op in charge has the final say in what firing systems may be used at any event. The consensus best path forward was progressing slowly by starting with LED lights & low energy firings like model rockets. The aim is to build experience with and knowledge of these systems to determine if they can be safely used for more energetic firings. Richard & Dimitri plan to bring the Cobra and Wilson F/X systems up to the MTA event next weekend, where (with the permission of the Pyro Op in charge) they will be tested safely on a small scale.

NEXT MONTHLY MEETING

The next RRS monthly meeting will be held virtually on Friday, April 9th at 7:30 pm pacific time. Current members will receive an invite via e-mail the week of the meeting. Non-members can request an invitation by sending an email to:

secretary@rrs.org

The Executive Council has committed to an additional monthly meeting moving forward to address administrative matters. Members who would like to discuss an admin topic in detail can request attendance at a Council meeting by sending an email to the Secretary at the address above.