The Reaction Research Society met on September 11, 2020, by teleconference. Several members called in from out of state. After calling the meeting to order and the reading of the treasurer’s report, we began to discuss events to come and those in planning.
MTA WORK EVENT 10/3/2020
The next event at the Mojave Test Area will be on Saturday, October 3rd. This will be a work event to repair our large adjustable rail launcher, remove tumbleweeds and brush from around our site, fix the two cut strands of barbed wire at our front gate, clean off corrosion from several areas and also potentially replace the bent panel on the vertical thrust stand. Osvaldo is leading the work event and all members are encouraged to come out. In addition to bringing sunscreeen, proper desert attire and footwear, bringing work gloves will be very useful.
As with all events at the MTA, social distancing and facemasks are required by all attendees at this event. Newcomers must request permission to attend and sign our indemnification waiver in advance of their arrival. See our website for these forms and submit them to the RRS president.
At this same event, we may also have a few launches if members are ready to do so. Dave Nordling was appointed to be the pyro-op in charge for this day. Wolfram Blume had planned to attempt his first flight of the two-stage Gas Guzzler to verify the staging and recovery systems. The nitrous-oxide hybrid motor is also ready for another launch attempt at this event.
Bill Inman also plans to join us at the MTA to conduct some tests of his solar concentrator to be used with his next generation steam rocket still in build.
NEW RESTROOM FACILITY AT THE MTA
Last year, the executive council set priorities for improvements at the Mojave Test Area. At the top of the list was building a new restroom facility which would offer our guests greater comfort than the current facility.
Larry Hoffing and Dave Nordling have begun to approach potential contractors willing and able to build a modest facility at our site. No formal proposals have yet been received yet but the society expects to have more to share in the coming month. With the hot summer months receding and the cooler temperatures of autumn approaching it is a perfect time to begin this project.
Given our modest budget, we are asking for donations to help the society make this much asked for and much needed improvement. Donations to the RRS are tax deductible as we are a registered 501(c)3 educational non-profit group in California. Our Paypal link is one our website and if there are any questions please contact the RRS president or any member of the executive council.
2021 RRS SYMPOSIUM
It was recommended that we try to set a firm date for the 2021 RRS Symposium with the Ken Nakaoka Community Center on a Saturday in late March. Although it is not certain if the symposium can be held, preparation for the symposium can take many months. Frank was going to see if a tenative date could be established only for planning purposes. If COVID-19 restrictions in Los Angeles were lifted to allow our symposium, we would have little time for advanced planning. There’s liitle to lose in scheduling the event and postponing if it becomes necessary.
Contact the RRS secretary with questions. Next meeting will be held virtually on October 9, 2020, 7:30pm. Contact the RRS secretary for details.
Our June meeting was held by teleconference on June 12th starting at 7:30pm as planned. Some people did not seem to get the email link with the information to call-in. As always, members are responsible for keeping their contact information current including their emails. Please contact the RRS treasurer with your updated contact information so that all active members can be on distribution.
We had over a dozen people calling in which is a fairly good turn-out under these quarantine circumstances. Some of our members actually appreciated being able to call-in rather than travel all the way to Gardena.
Chris Lujan, our treasurer, was able to set this meeting up for us. Based on the success of the last two meetings, the RRS will make teleconferences a regular part of our meetings even when we return to in-person meetings. It allows more of us to connect around our local area. Many of us miss the face to face interaction which we hope will return some day soon.
Dave Nordling and Larry Hoffing gave an update on the next flight of the hybrid rocket. A new rocket body is being made and a better means of ignition will be attempted that should more reliably sever the nitrous fill line.
Wolfram is still working on subsystem tests of his Gas Guzzler ramjet. He has rebuilt damaged parts and is conducting burner tests to verify important aspects of his design. He may not return to testing at the MTA until October 2020 when the weather is likely to be cooler.
John Krell has built a pair of custom avionics chips that can record altitude and accelerations at rapid data rates (1 kHz). They are small enough to fit in a standard alpha payload tube. Integration activities are underway. Frank has many of the recovered alphas in storage which often have their payload tubes intact for re-use after some clean up.
Keith Yoerg recently retired his latest rocket after 10 flights and achieving certification with it. He may start a new build but that remains open.
Next MTA launch date was tentatively set for July 25th. We hope to fly some alphas including one with a longer propellant tube (4-feet) in order to compare the results from John’s avionics.
Bill Inman has decided to rejoin the RRS after being away for many years. He was the builder of the Scalded Cat steam rocket and is working on a new design iteration to fly soon at the RRS MTA. A reprinting of his March 2001 article on the Scalded Cat will soon post to our website for those wanted to see this work in detail.
The next monthly meeting of the RRS will be July 10th. We are presuming this to be another teleconference only unless LA County lifts the quarantine restrictions and the Ken Nakaoka Community Center re-opens.
Waldo Stakes will be holding a memorial service for Mad Mike Hughes at 12 noon, July 18, 2020, at the 247 Cafe in Lucerne Valley, CA. Mad Mike was killed in the last flight of his steam-powered manned rocket flight outside of Amboy, CA, on February 22, 2020.
Mad Mike wasn’t a member of the RRS but he was one of our exhibitors at the 2019 Symposium last year. He had his rocket, the Juan Pollo, on display and many people had the chance to meet him. He will be missed by his family and friends including some of our membership.
The RRS held a launch event on Sunday, March 1st, 2020, at the Mojave Test Area. It was a brisk morning with steady winds that occasionally slowed enough for a safe launch.
This launch event was originally for a university static fire and a few member projects. The university had to reschedule but we had sufficient interest from our own projects so we held the event.
The weather was a concern with passing storms and rain predicted earlier in the week. But as often happens, the weather shifted for the better on launch day with winds staying low enough to launch most of our projects.
Wolfram has been working for a few years on his Gas Guzzler ramjet rocket. He is just now entering the first system flight tests to demonstrate the staging and recovery systems. He filled his ramjet with water in place of the gasoline to have a representative weight.
Wolfram was able to load his booster on to the 1515 rails with good alignment. His upper stage had some alignment problems due to using a different prototype for this initial flight. After some examinations on the pad, he pulled his rocket stages back to the Dosa building for internal adjustments to assure a clean fit between the booster and upper stage.
The next launch was Keith Yoerg’s high powered rocket, Charlie Horse. He used an I-350 Smoky Sam motor and had a dual-deployment system with a GPS tracker built in. The flight was smooth off the rails but the trajectory data seemed to show a steady wind pushing west to east. He reached an apogee of around 4000 feet. Recovery wasn’t a problem as his rocket landed just a hundred yards east of the RRS MTA.
Wolfram returned his rocket to the pad but accidentally dropped the second stage breaking a piece of the ramjet plastic cowl on the concrete below. With this significant disruption of the aerodynamic surface, he was forced to abort the flight and rework this part. He was also going to check some of the other parts in his assembly for this long-awaited first flight. It’s important to not rush a project and wait until all is ready for a successful flight.
The next flight was to be the hybrid rocket that Larry, Osvaldo and I have been working. The Contrails H222 motor was safely loaded from last month and after some improvements to the vehicle body for better parachute recovery functions, we felt we were ready.
The winds were still favorable so we proceeded with clearing the area and making our electrical connections back to the old blockhouse. With just a handful of people and the lightweight vehicle, the old blockhouse was sufficient for our operations that day.
The nitrous bottle was refilled from the prior week and the manifold was plumbed to the vehicle tank. With the opening of the nitrous bottle, remote operations could begin. The time of tanking the small 38mm H-motor tank was not precisely known, but was not expected to take very long given basic calculations of the available flow rate. As expected, the tank volume primed within 15-20 seconds. We waited a full minute as we were initially unsure of whether the full volume was filled with liquid. After spotting a jet of liquid escaping from the vehicle body vent, we were assured that the hybrid motor was ready to be ignited.
Osvaldo conducted the firing operation after a short five-count. The resistor and Pyrodex charge ignited after a slight delay for the resistor to heat up sufficiently. The motor seemed to reach full thrust quickly and leave the rail as expected from the thrust curves from this commercial motor.
The vehicle was spotted tumbling after leaving the rails leading us to believe the rocket was not properly balanced. More detailed calculations would have been beneficial, but from initial estimates and the heavier recovery system in the extended rocket body, it was believed the rocket would be stable enough.
Examination of Osvaldo’s high speed camera footage from the hybrid flight revealed the reason for the vehicle tumbling. Some of the frames show that the nitrous fill line remained attached to the rocket during launch and even after clearing the rails. The fill line did snap loose in the flight at some point, but it was supposed to completely sever at ignition. This imparted a significant torque to the vehicle leading to a tumbling and short trajectory back to ground.
Worse, in my rush to get the hybrid loaded on the rails and made ready for filling operations, I forgot to arm the recovery system. This is a classic mistake and one that I could have easily avoided.
At least, the other issues with the flight limited the distance the rocket travelled. The rocket was recovered just north of the 1010 launch rail still within the bounds of the MTA. The rocket landed on its nose breaking it and significant body tube damage was sustained. After disassembling the hybrid motor from the body, we opted to scrap the rocket body and rebuild a new one for the next flight. The fill and fire operations were successful and the equipment we built worked fine.
The Contrails H222 motor parts survived well. We were able to easily remove the motor assembly and disassembled the parts for inspection. The graphite nozzle showed very little ablation and will be reused. None of the parts had heat damage. The fuel grain didn’t exhibit much ablation as compared to the other unburned grains we had. The burn duration in flight seemed to be similar to what is shown on the thrust curve, but this should be reviewed against the flight footage.
More review of the flight footage will be necessary to better understand how the hybrid motor operated. We are considering changing the ignition method to use an electric match and maybe a shape charge that would better ignite the hybrid motor.
We are considering building a static testing rig for the hybrid motor to verify some changes we intend to try with the ignition. There will be more on this subject in later reports.
Larry Hoffing had built a custom composite solid rocket motor using a spent casing from a commercial solid motor. This simple end-burner grain also had a custom-made nozzle. Larry had suspended his experimental motor a length of metal piping threaded on our large adjustable box rails that is still undergoing refurbishment.
Unfortunately, Larry’s motor design was not successful and rapidly overpressurized scattering both end caps and propellant grain fragments across the desert floor. No fires resulted from this static firing failure and no serious damage was done to nearby structures used for this demonstration.
The last launch attempt was Keith Yoerg’s smaller model rockets using the tiny B and C motors. The winds became stronger as the day progressed and by that time sustained wind levels were too high for any launch particularly for such a small vehicle. These rockets would be saved for a later event and Keith began examining his Charlie Horse rocket and its camera footage.
It was a good day for the RRS to have a launch event exclusively for our member projects. We plan to hold more of these events for both universities and our membership very soon.