MTA launch event, 2021-01-09

by the Reaction Research Society


The Reaction Research Society held its first launch event of the new year on Saturday, January 9, 2021.  Dave Nordling was the pyro-op in charge.  We had a couple rockets prepared and some maintenance work we wanted to continue.  Dmitri Timohovich brought his whole family to the event and we enjoyed grilled burgers there at the Mojave Test Area.  The January winds were light and cool that day.  It was a good day for launch.

Bill Inman enjoys a burger in the George Dosa Building
Everyone relaxing for a short lunch before getting to launch.

Wolfram Blume brought his two-stage rocket, the Gas Guzzler.  His ramjet upper stage was rebuilt from last year’s unfortunate breakage when dropped during loading on the launch rail last year.  3D-printed plastic parts can sometimes be very brittle and care must be taken.

The 1515 launch rail was put into position with some help from Bill Inman and a few others.  Bill Inman is still working on his solar tracker for his latest iteration of the Scalded Cat.  He made the trip from Carson City to the Mojave Test Area to help others with operations and we were very thankful.

Wolfram was able to mount his booster stage on the rails and carefully erect the launcher.  The booster uses a commercial solid motor, an Aerotech “K” motor.  

Wolfram cleans the 1515 rail at the RRS MTA in preparation for mounting the booster
Wolfram’s booster sits on the launch rail

The ramjet for this first flight was loaded with water to simulate the weight, but would not be fired.  The primary goal was to demonstrate the staging and recovery systems powered only by the booster.  Wolfram went back to the loading area to complete the preparations of the upper stage. During a system checkout, the parachute deployment charge fired.  After some careful examination, the source of the problem seemed to be related to errant software commands.  Wolfram aborted his launch attempt and returned with his rocket stages for further examination back in Los Angeles.  Although the charges could be reloaded, he could not be certain that an early parachute deployment would occur and wreck his vehicle during flight.

The Gas Guzzler upper stage ramjet

Dmitri Timohovich and Waldo Stakes worked on completing the welding of the new steel plate on the vertical test stand. This plate on the vertical test stand was damaged during a test failure many years back and late last year was finally cut out and the space grinded to fit a replacement plate.  Unfortunately, the stick welding system would require a different type of welder and a more powerful source to drop a reliable weld.  The welding of the plate will be reattempted at the next event.

With the grinding complete, the plate is fitted and ready to be welded in place

The second launch of the day would be Dave Nordling’s nitrous oxide hybrid rocket.  This 38mm H-sized commercial hybrid motor kit from Contrails Rocketry (H-222 model) had a modified igniter and was mounted in a new 4-inch body made by Larry Hoffing. The prior launch attempt had issues with severing the nylon plastic filling line so the ignition energy was increased with small bit of composite solid propellant ignited by an electric match.

Several minor problems occurred during launch preparations. The nitrous bottle and manifold filling system was working well but the electrical control box failed during tests.  After some discussion, the defective switch box was removed and we were able to fire and get a clean launch

Dave Nordling leans against the old blockhouse with the second build of the hybrid rocket waiting for launch
The hybrid sits on the 1010 launch rail

We repacked the motor before launch and adjusted the vent tube to be more visible. The filling of the rocket went quickly and smoothly, only about 20 seconds before the white stream of liquid could be seen. The filling was stopped and with a short five-count and the rocket was fired. The rocket came off the rails quickly and it seemed that the modified igniter worked. The big problem was the parachute recovery switch wasn’t turned on before launch. This simple oversight would mean a rebuild would be necessary.

The simplest error can lead to sad results.

The rocket was recovered on the north end of the MTA site. It only seemed to reach about 300 feet of altitude. Unfortunately the ballistic landing broke both stages and the internal motor mounts and a complete rebuild is necessary. The motor case was parts were in tact and so it was extracted and will be reloaded,

The hybrid motor seems to arc to the north against wind.

Beckie Timohovich recorded the hybrid flight on her phone, The rocket seemed to immediately curve to the north off the rails opposite of the wind. It seems that the nylon fill line might be still holding fast despite the added solid propellant charge. The 3/16-inch nylon plastic line being strong enough to hold back the 900 psi nitrous pressure, it also poses a challenge to cut cleanly from the ignition charge. A static firing of the motor will be done next to get a better look at how well the fill line severs and measure the thrust curve directly..

The remnant of the fill line from within the hybrid after firing. The end looks smoothly extruded.

After recovering the hybrid rocket and putting away the equipment, we flew a water rocket for Dmitri’s young son. Although very simple, these things are very fun.

Max Timohovich holds the water rocket fired several times at the end of the afternoon.

The event was a partial success and there is more work to be done on our facilities including adding a new toilet facility at our site and welding in the plate on the vertical test stand. The next hybrid rocket launch may be a couple months away, but Bill Inman may have his next design of his solar heated steam rocket ready for launch af fhe MTA in a few weeks. He had his first successful flight in the Nevada desert just before Christmas. He is getting ready for a flight from the RRS MTA.

Bill Inman has his first successful flight of his solar-powered steam rocket on 12/22/2020

Wolfram seemed confident that he too might be ready to try his first launch of the Gas Guzzler at about that same time. If the next launch event occurs before the next monthly meeting on February 12, 2021, the announcement will come through the society email list.

The sun sets at the RRS MTA after a good day.

June 2020 Meeting – *Virtual Only*

by Dave Nordling, Reaction Research Society

written by permission from the RRS Secretary


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.

treasurer@rrs.org

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.

RRS members from around the city call into the June 2020 monthly meeting.

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.

The RRS has it’s second monthly meeting by teleconference due to COVID-19 concerns.

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.

New rocket body still in build. Hybrid motor was fitted, but recovery system needs to be installed.

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.

Wolfram Blume’s Gas Guzzler two-stage ramjet prototype sits on display.

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.

A recovered alpha payload tube ready for re-use with another alpha propellant tube.

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.

Bill Inman (right) at the RRS MTA working on his launch rail.

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.

Contact the RRS secretary with questions.

secretary@rrs.org


ADDENDUM

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 Hughes (left) and Waldo Stakes (right) in front of the “Juan Pollo” manned steam rocket at the 2019 RRS symposium in Gardena, California.

https://www.cnn.com/2020/02/22/us/science-channel-mike-hughes-dead/index.html

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.


MTA launch, 2020-03-01

by Dave Nordling, RRS.ORG


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.

View from behind the RRS MTA large test stand, 2020-03-01

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’s booster sits on its stand in the Dosa Building

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.

The Gas GUzzler booster stage on the 1515 rails, loaded and ready
Both stages of the Gas Guzzler sit on the 1515 rails as Wolfram inspects the fit between them

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.

Kieth Yoerg’s rocket, Charlie Horse is made ready for flight from the 1010 rail
Charlie Horse rises on the black plume of a Smoky Sam high-powered motor.

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 stands with his ramjet upper stage and its broken cowl piece. Some rework will be required.

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.

Osvaldo and Larry check the payload packaging of the hybrid rocket one last time
The hybrid motor is installed and ready for today’s launch.

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 RRS nitrous oxide bottle ready to fill our hybrid rocket motor

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.

Kieth Yoerg’s onboard camera takes a test photo of me loading the hybrid motor on the 1010 rail

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.

Note the nylon filling line is still attached as the rocket leaves the rails
Just a little later in the high speed footage the fill line and igniter cable start to come out, but the rocket is already knocked off course.
Both the fill line and cables are free of the rocket while the nitrous still flows over the fuel grain and the motor is lit.

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 first hybrid rocket destroyed in flight. A new rocket build will start soon.
The spent hybrid fuel grain extracted from the Controls H222 motor tube.

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 holds his experimental solid motor, a simple end burner to test his mixture
Larry suspends his motor from an old steel rod from our modular rail system still under repair

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.

Still image from Larry’s motor firing, rapid overpressurization just after ignition

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.

Larry’s motor case ripped at both ends, back to the drawing board

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.

Kieth’s model rocket launcher being brought back to the Dosa Building as high winds prevented further launches that day.
Tiny desert flowers bloom in the spring at the RRS MTA

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.