RRS attended the 1st annual FAR Liquid Rocket Symposium

by Dave Nordling, President, RRS.ORG


Representatives of the Reaction Research Society were invited to attend the 1st annual Friends of Amateur Rocketry (FAR) liquid propellant rocket symposium at the EAA Chapter 1 headquarters at the Flabob Airport in Riverside, California, on January 28, 2023. Dimitri Timohovich and I came to observe and participate in the all-day event including a range of topics related to safe design and operations with liquid rockets. There were hardware demonstrations giving attendees a direct appreciation for the importance of safety and careful planning with their system designs.

The intended audience was university rocket teams looking for best practices and expert advice. Mark Holthaus (president of FAR), Mark Ventura (RRS member and owner of Ventura Energy Systems) and Derek Honkawa (FAR member and private business owner) all gave excellent presentations covering igniters, propellant handling, part cleaning, and pressure system safety with a generous amount of examples of successful and unsuccessful projects at FAR.

FAR will soon make their presentation files available on their website for download. The RRS was glad to be there for this first of its kind event.

The RRS similarly has experts that have supported liquid rocket projects for decades at the Mojave Test Area. Contact the RRS president for requests and scheduling.

Also, the RRS will be holding our 80th anniversary symposium on April 15th at a venue location to be announced soon. This will be our first symposium since the pandemic and we look forward to having many speakers from industry, government, academia and the hobbyist community on topics related to liquid propellant rockets and many other subjects of interest to our public audience.

Sunrise at the Flabob Airport in Riverside, California.
For early cold mornings, coffee helps.
Pressurized water flow testing rig on display.
A full day of presentations on topics related to liquid rockets.

January 2023 meeting

by Joel Cool-Panama, Secretary, RRS.ORG


The Reaction Research Society held its monthly meeting at the front office of the Compton/Woodley Airport, 7:30 PM PST. on Friday, January 13, 2023.

Agenda topics of the meeting were:

  1. Welding helmets (Mohammed)
  2. Gas Guzzler progress (Wolfram)
  3. 1/14/2023 launch event
  4. * ROC high-power launches, terms of granting membership
  5. * American Artist – LACMA
  6. Work event 1/22-1/25/23
  7. launch event on 1/28/2023?
  8. 2023 symposium on April 8 (Frank)
  9. FAR liquid rocket symposium 1/28/23 at Flabob Airport (Dave)
  10. Restroom progress (Dimitri)
  11. Compton Comet work at MTA (Jamie)
  12. Launch rail designs (Jackson)
  13. Visit to Ventura Energy LLC, 1/12/23
  14. micrograin resources, alpha (Jim Gross)

Past Events

Another update which we were pleased to announce is that the President of the society has been formally admitted to the CALFIRE subcommittee on Fireworks, under which rocketry is governed, and which will be rewriting the existing regulations.

The Compton Comet project also had its first low pressure test earlier this month. There were many leaks, but the team is now nearing the point that they will need to carry on their testing at the Mojave Test Area (MTA).

A new member to the society, Abdullah Daya, also asked if there was any certificate available for those members who attended the society welding class in Vista. It was decided that the society would ask the instructors at a later time.

Current Events

The society is pleased to announce that member, Wolfram Blume, is currently seeking his pyro-op license. He currently only plans to obtain a Class 3 Rockets license, but the society currently seeks to expand its license holder count which will ease the planning of future MTA events requiring the presence of the same.

There was also a fairly lengthy discussion regarding society owned tools. Society member Mohammed Daya researched welding helmets on behalf of the society, giving a recommendation for a particular brand out of a few. There was also a recommendation for individuals to use prescription lenses, and helmets with small viewports should be used to prevent ones vision from wandering.

There was also discussion of a new requirement that individuals using society equipment sign waivers to reduce our liability, similar to the waiver required for MTA use.

Unfortunately, due to the recent weather in California, the launch event on January 14th for a project by American Artist has been cancelled. Dave still wishes to meet with him at another time, and hopefully schedule another date for his project at the MTA.

Another unfortunate situation has occurred, in that the FAA has reduced ROC’s height waiver by a substantial amount (7,000 feet). This will make the larger high-power launches impossible from their Lucerne Valley location. However, it was suggested that the society could reach out to ROC, and offer them use of the RRS MTA for their launch events. Keith Yoerg said he’d reach out to start a conversation.

In regards to the RRS MTA site improvements, the creation of more launch rails therefore was discussed. Materials for the construction of the same have been bought, and their design was briefly debated, with radio towers being mentioned as a frequent base. It was also mentioned that CAD software would be useful in our construction of any of the larger rail designs. A 60-foot launch rail for liquid-fuelled rockets is a top priority at the society this year.

An update on USPS protocols has been announced, that all mail addressed to a PO box must now also give the street address of the Post Office it is located at. Any such mail without an address will be returned to sender, so mail to the society should have the address written as such.

Reaction Research Society

8821 Aviation Blvd.

P.O. Box 90933

Los Angeles, CA, 90009-0933

An unexpected but minor blow to the society’s fundraising was delivered recently when Amazon announced that the AmazonSmile program will be discontinued in February this year. The money earned by the society therefrom was not a vast sum, but per our treasurer, Larry Hoffing, the loss of this small revenue stream means that pizza parties will be cancelled indefinitely. The society has yet to hold one of these events but the loss will still be felt.

Future Events

Starting on Sunday the 22nd, we are planning to have a multi-day work event at the MTA. This will do work on lighting and other electrical work on the site. Handicap rails and an access ramp also need to be installed soon. Dimitri will be present, and other volunteers are encouraged to participate as well.

On January 28th, there is another planned launch event for those wanting training in micrograin loading amoxil and launching. Jim Gross will be the pyro-op in charge.

Also on the same day, FAR will be holding a liquid rocket symposium at the Flabob Airport in Riverside. The RRS has been invited, but due to the limited gathering size only a couple individuals from the society will attend.

This April, Bill Claybaugh is planning to launch from the MTA. Likewise, the RRS symposium is planned to take place some time in April. Frank is currently in contact with the Gardena Community Center to see if we can hold the event there again this year on our 80th anniversary.

In regards to the symposium, there is currently no set budget, but it has been suggested that some of the society’s generous benefactors might be contacted to help cover costs.

Jim is currently in possession of zinc that might be used for sulfur micrograin. Some, contained in pales, are known to be good, but some received by mail are of unknown condition. It’s expected that the latter will be tested order phentermine soon so as to determine its use.

Next meeting will be February 10th. Contact the secretary for details.


MTA Launch Event, 2021-10-16, First Update

by Bill Claybaugh, RRS.ORG


In a remarkable demonstration of persistence and luck, RRS President Osvaldo Tarditti was able to find the spent booster rocket. A few photos were captured of the recovered rocket.

Bill Claybaugh’s recovered spent booster casing brought back to the Mojave Test Area (MTA)
Closeup on the bulkhead shoved into the aluminum case of the booster from the impact.
The fins look great and the nozzle was recovered.

Based on the impact location, it was possible to reconstruct a possible flight trajectory by assuming the motor performed as designed and further assuming the front of the vehicle was a flat plate and that the mass did not include the mass of the payload.  We know from video, telemetry, and recovery of the payload that the payload separated from the booster about one second into the flight.

The recovery location on the map shows a northeast trajectory as confirmed by launch footage.

This analysis suggests a burnout velocity of about 1550 feet/second with a peak altitude of about 21,200 feet given the known range of about 14,300 feet. This analysis gives a flight time of about 74.5 seconds and an impact velocity of about 820 feet/second.

Given the observation that the vehicle stopped in about 2 inches (based on the depth of the depression in the hardpan) before falling on its side; we can estimate the impact deceleration.  Given an average velocity during impact of about 410 feet/second because the final velocity is zero and it took only 0.167 feet to come to rest, it follows that the impact occurred over 0.000407 seconds.  This, in turn, indicates an average deceleration of about 31,250 g’s.

The reason for the vehicle turning to the Northeast starting at about 0.20 seconds into the flight remains unclear. There is no evidence either in video or in images of the recovered hardware of any hot gas leak nor of any transient thrust vector anomaly.  The wind was less than 5 miles per hour and from the Northwest; if it had caused a turn, we would expect it to be toward the Northwest, not the Northeast as observed.  The only plausible theory at this time is that part of the belly-band became embedded between the nose of a fin and the rocket body causing the turn via differential drag and then fell away from the vehicle, causing the resumption of normal flight.  Once the recovered hardware is available for inspection, we will test each fin nose to see if a gap exists that might have caught the 0.020-inch thick belly-band.

The recovered payload segment was examined after it was found just north of the launch site.

It also remains unclear as to why the payload separated about 1 second after launch.  The recovered payload showed that both initiators had fired (by design, if one fires the other is ignited; thus, only one signal is required to fire both) but did not show any evidence of having been “swaged” or otherwise subject to being forced off the rocket by aerodynamic or other forces. Neither does the matching front end of the rocket show any evidence for the payload having been forced off. We thus conclude that one of the flight computers ordered the firing of the initiators.

The bellybands being fit checked in the launch rail.
Recovered bellybands have evidence of tearing from what is likely fin impact.

However, the main flight computer stopped working just after 0.80 seconds into the flight for an unknown reason after recovery it was still connected to its battery, which showed the expected 3.87 volts. Further, the limited data recovered from that computer shows that it did not initiate separation of the payload: the firing circuit shows continuity throughout the period that the computer was operating and separately records that no signal was sent by that computer.

Still image of the rocket just after launch making the unexpected hard turn.

This points to the backup flight computer.  That hardware is currently at the manufacture for repair, after which we hope to extract continuity data with regard to its firing status.  Hopefully, once that and other data is available from the backup computer we will be able to establish when it ordered the separation of the payload, and why.

Recovered payload with the main and backup computer.

A second update to this firing report is expected. The booster has been packaged up for a more detailed inspection.