Tag Archives: MTA

November 2021 Virtual Meeting

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by Keith Yoerg (RRS Secretary)

The latest meeting of the Reaction Research Society took place Friday, November 11th and had 14 attendees. After a brief discussion on updates to this website (which are currently underway), we got the meeting started.

Screenshot of discussion during the monthly meeting

NOMINATIONS FOR 2022 RRS EXECUTIVE COUNCIL ELECTIONS

Official proceedings began with the nomination of Drew Cortopassi as the election chairman for this year. The following candidates were nominated to the ballot for the listed offices (write-in candidates are allowed).

President:    David Nordling (new)
Vice President:    Frank Miuccio (incumbent)
Secretary:    Keith Yoerg (incumbent)
Treasurer:    Larry Hoffing (incumbent)

Administrative and lifetime members should have received a ballot via email. If you believe you should have received a ballot but did not, please contact the RRS treasurer (treasurer@rrs.org). Ballots must be submitted by Thursday, December 9, 2021. Election results will be announced at the December monthly meeting on Friday the 10th.

BLOCKHOUSE ROOF REPAIR RECAP

With the election business handled, Osvaldo proceeded to extend a hardy thank-you to the RRS members who assisted in replacing the aging blockhouse roof earlier in the month: Dimitri, Bill, Jon, and Keith. A few photos and a time-lapse video of the process were shown, and an extra thank-you was extended to Dimitri for his efforts over several weekends to both finish the roof and haul the materials to and from the MTA. A more detailed write-up of the process from Dimitri is available on this blog here.

DISCUSSION OF UPCOMING MTA EVENTS

Several groups appeared ready to take advantage of the cooler desert weather during the upcoming month. Most of these events have already taken place at the time of the writing of this report, but were still in the planning stages during the meeting. Reports will be available on this site for each event if they are not already.

The planned events included: on November 20th, UCLA conducting a static firing of an ethanol-LOX liquid rocket in support of attempting to earn the FAR-Mars prize for an altitude of 30,000 ft; on November 28th, Keith Yoerg launching his 8″ diameter, 13′ tall rocket “The Hawk” on a 98mm solid rocket motor; and on December 4th, USC conducting further tests on their 8″ solid rocket motor. Wolfram Blume also expressed interest in attending to continue work on his rocket the “Gas Guzzler.”

YOUTH ROCKETRY CLASSES

Frank updated the membership on the youth rocketry classes. The launch date for the class in Boyle Heights was rescheduled to January 22nd because of concern the students and group may not have had the logistics prepared for the field trip.

Classes with the “Strive” group (which had been discussed in more detail during previous meetings & their write-ups) have been scheduled to run from February 2nd – March 2nd at 4pm on Wednesdays. The launch for this class will take place on March 5th, with March 12th reserved as a contingency day. The plan is to use lessons learned from the Boyle Heights class to help inform how this class will be run, which will also use Baby Berth Estes model rocket kits so that each student will be able to take a rocket home after the launch. Frank is also working with the LAPD “Community Safety Program” (CSP) to schedule a class with that group for the summer of 2022.

Osvaldo showing off the e-match igniters sized for use in model rocket motors

Talking about the classes kicked off a discussion of the support the society has prepared for the launch day during these classes. Osvaldo showed an example of the igniters which we plan to use – something far more reliable than the nichrome wire igniters included with Estes rocket kits. Larry and Dimitri shared what they had learned about the Cobra Wireless Firing System which we intend to use to launch the rockets. Dave Nordling also updated the attendees on the status of the PVC launch pad systems he has been working on.

MISCELLANEOUS DISCUSSION

More RRS members keep catching the bug and deciding to build model rockets! Chris Lujan showed of a model rocket kit that he built with his son and they plan to launch during the next youth launch up at the MTA.

Chris showing off the rocket he built with his son

Keith Yoerg then did an impromptu presentation on the build process that he used for his rocket “The Hawk” by showing a series of photos that he took along the way. This project has been in process since early 2021, and it is very exciting to see it nearly complete!

Photo showing the epoxy injection process for the internal fin fillets on “The Hawk”

Fred Radford then shared about his 8″ rocket – one very similar to “The Hawk” – including some very clever tools for sanding and the build process. This rocket is expected to use s C02 cartridge system for the parachute deployment. Fred is building this and other rockets out of a Maker Nexus makerspace in the Bay Area of California, where he operates his nonprofit “Space Makerspace” to teach kids how to build rockets.

Photo of several of the rockets built in Fred’s classes

NEXT MONTHLY MEETING

The next RRS monthly meeting will be held virtually on Friday, December 10th at 7:30 pm pacific time. Current members will receive an invite via e-mail the week of the meeting. Non-members (or members who have not received recent invites) can request an invitation by sending an email to:

secretary@rrs.org

Please check your spam folders and add secretary@rrs.org to your email whitelist to make sure you receive the invitation.

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

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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.

MTA Launch Event, 2021-09-26

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by Keith Yoerg, Reaction Research Society Secretary

The RRS Mojave Test Area (MTA) hosted a launch event and work party on Sunday, September 26th. The USC Rocket Propulsion Lab (USCRPL) had arrived a few days earlier to prepare for a static firing of their 8″ diameter solid rocket motor named “Earthshaker II” which took place on the 26th. Several RRS members also answered the “Yoerg Challenge” to launch model rockets, and Dimitri was out with his water rockets. On the work side of things the Dosa building was re-organized, a security camera was installed, and a discussion began on how best to replace the aging roof on the blockhouse.

USCRPL 8″ SOLID ROCKET STATIC TEST

USCRPL had their setup ready for a static test of their 8″ solid rocket motor in the late afternoon, which was secured below the vertical test stand. Unfortunately, shortly after coming up to full power the motor exploded. All personnel were at a safe distance in the bunker and no one was injured. RRS President and Pyrotechnic Operator in charge Osvaldo approached the site once it was safe and extinguished the resulting flames.

Still shot from a video of the USCRPL motor explosion
Pyrotechnic Operator Osvaldo bringing a fire extinguisher to the lingering fires

All requests to use the RRS MTA must be made to the RRS president and reviewed by the executive council.  For any questions about this test series or any future test series, please contact the RRS president.

president@rrs.org

YOERG CHALLENGE MODEL ROCKET LAUNCHES

Many RRS members had model rockets on hand to answer the “Yoerg Challenge” and launch at the MTA site. Dimitri and his son Max launched a “Helios” and “Dazzler” on C6-3 motors. Keith launched a “Baby Bertha” on a B6-4 and a “Big Bertha” on a B6-2. Dave Nordling launched a “Baby Bertha” on an A motor. Bill Inman & Jon Wells also launched model rocket kits, and John Krell launched a model kit on a G motor. (I will endeavor to do a better job of recording the rockets & motors that everyone uses at these launches for more specific reports in the future).

Keith Yoerg, Bill Inman (on the launch box), Waldo Stakes and Diana Castillo wait as the countdown progresses.

We did not have the new wireless Cobra firing system at the MTA site during this event, so we used the 4-pad controller that Dimitri built earlier this year. The controller split its time between this low-power launch pad and the water rockets which Dimitri had set up on the underground blockhouse.

Several of the model rockets ready to launch on the PVC launch pad built by Keith Yoerg

I will also mention that prior to these launches, we enjoyed a nice potluck BBQ of brats, (homegrown) potato salad, chips, beans, and corn. Several members contributed food which was expertly prepared by Becky. We’ve been doing this more often and seem to keep getting better at it every time!

WORK PARTY TASKS

In addition to the more exciting “fiery” aspects of the day, RRS members also completed a lot of routine maintenance at the MTA site. We completed several general organization tasks in the Dosa Building and the storage containers, and a security camera was installed on the Dosa Building. There was also a lengthy and robust conversation about methods to replace the aging blockhouse roof, which has been high on the the society’s list of desired site improvements for several years.

Keith Yoerg and Jon Wells discuss options for repairing the old blockhouse roof.
Security camera installed on the Dosa Building