Poor Man’s Acoustic Analysis of Rocket Engines

by Richard Garcia, Director of Research, Reaction Research Society


In this first month of the new year, 2022, a new technical article is now available to RRS members only. This article will be one in a quarterly series of technical subjects explored that are relevant to amateur rocketry.

Combustion instability is a common concern in the development of new liquid rocket engines and in solid motors. Although not as commonly found in the smaller engine designs of amateur rocketry, it has been seen in some cases. A simple and inexpensive method of conducting acoustic analysis of rocket engine behavior in hot-fire is discussed.

The article will be kept in the society library. Contact the director of research for inquiries.

research@rrs.org


December 2021 Virtual Meeting


by Keith Yoerg (RRS Secretary)


The latest meeting of the Reaction Research Society took place by teleconference on Friday, December 10th and had twelve attendees.

Screenshot of discussion during the monthly meeting

RECAP OF KEITH YOERG’S NOVEMBER LAUNCH OF “THE HAWK”

Keith kicked off the meeting with a recap of the first launch of his rocket “The Hawk” an 8-inch diameter 14-foot tall rocket that was flown from the RRS Mojave Test Area on November 28th. The rocket utilized the 1515 rail launcher which was secured in place to one of the concrete pads using sandbags and tie-downs. The motor was a 98mm Cesaroni M1790 Skidmark which features sparks in the trail.

First launch of Keith Yoerg’s rocket “The Hawk”

Keith shared some slow-motion video of the flight captured with a GoPro camera and other data from the flight, including a 3D flight path. The rocket reached an altitude of 4,846 feet as measured by the barometer on the onboard AltusMetrum Telemega flight computer, and was successfully recovered with only minimal damage to the body tube. The rocket is in the process of being prepared for another launch on December 17th to coincide with the anniversary of the Wright Brothers first flight.

Map of the flight path with barometric altitudes in red and GPS in blue. The GPS appears less reliable on this flight.

RESULTS OF THE 2022 RRS EXECUTIVE COUNCIL ELECTIONS

Election chairman Drew Cortopassi presented the results of the 2022 executive council elections. The RRS Executive Council for 2022 is as follows:

President:    David Nordling
Vice President:    Frank Miuccio
Secretary:    Keith Yoerg
Treasurer:    Larry Hoffing

The society members in attendance congratulated the incoming new president and other incumbent officers and expressed their gratitude to outgoing president Osvaldo Tarditti for his stewardship of the organization. Osvaldo noted that the future of the group looks bright, and promised to send anyone who asks him a question a photo of him fishing.

USC SOLID ROCKET GRAINS STATIC FIRING

Osvaldo and Dimitri provided a recap of the lengthy solid rocket motor testing campaign that USC conducted at the MTA from December 4-5. On Saturday the 4th, the team worked through the night until around 2 am to be able to complete their goal of firing 20 separate grains of solid fuel by 2:45 pm on Sunday the 5th. The only reported mishap was that the U-Haul the USC team rented broke down just after leaving the dirt road to the MTA, which Dimitri suspected was because they had been using the battery from it to fire the rocket motors.

While the campaign was an ambitious one, the repetitious nature allowed them to get some of the younger students involved who wouldn’t normally be able to take part in on a day when only one motor is being fired. It was remarked that having more young members with hands-on experience is very good for the future of their program and the continuity of knowledge after the upperclassmen graduate. Dimitri mentioned that additional work will be needed to fill in the area of ground blasted away by all the recent USC solid rocket static firings – which has been affectionately named the “Trojan Trench.”

On the same weekend, a team at the FAR launch site launched their “Genesis” rocket – a hypergolic liquid propellant rocket that has been in development since the early 1980’s. Several RRS members had worked on the rocket at various times during its design and fabrication process. Unfortunately, the parachute system did not work and the tanks ruptured on the landing causing a small fire that self-extinguished but was visible from the MTA.

A THANK-YOU FOR DIMITRI’S RECENT WORK AT THE MTA

Our outgoing president, Osvaldo Tarditti, took a moment to extend a special thank you to RRS member Dimitri Timohovich for all of the recent work he has done in improving the facilities we have available at the MTA. Not only did he take the lead in the recent blockhouse roof repair which included several trips up to the site for the initial build, cutting the edges, and installing the tar paper, but he also donated four propane bottles for the society to use in the heaters and BBQ up at the Dosa Building.

The old blockhouse with a new roof.

In addition, Dimitri has agreed to take on the bulk of the work in building out the interior of the containerized bathroom. Three concrete pads have been poured at the MTA to accommodate this 20-foot high cube container as well as another one adjacent to it.

Future site of the RRS containerized restroom facility.

Osvaldo has procured most of the fixtures for the interior and plans to drop them off at Dimitri’s house – where the container will be delivered so that he can work on it more easily. Dimitri gave a tentative timeline of mid-January 2022 for when the container may be ready for transport out to the MTA.

PLANNING FOR MTA EVENT ON DECEMBER 17

Keith discussed his plans for a second launch of “The Hawk” on Friday, December 17th – this time on a Cesaroni N2600 motor. In addition, Dimitri has an RRS Standard Alpha rocket constructed and ready for launch and Osvaldo agreed to prepare one for Keith to get experience with the Zinc-Sulphur rockets. Dimitri volunteered to bring food for the group – award winning caribou chili made from meat they hunted, dressed, and prepped themselves in Alaska.

CALIFORNIA’S NEWEST ROCKETS CLASS 1 PYROTECHNICS OPERATOR

RRS member Dave Nordling informed the group that he recently learned that he passed his Class 1 Rockets Pyrotechnic Operator’s License exam. Congratulations Dave!

Office of the State Fire Marshall (OSFM) governs the licensing of pyrotechnic operators in California.

With additional members continuing to work towards earning their licenses, we can make sure that the RRS is able to accommodate a wide range of rocketry testing and schedule requests.

NEXT MONTHLY MEETING

As a reminder – yearly membership dues are due January 1st. Please click on the yellow “Donate” button on the right panel of this website to pay online via PayPal, or mail a check to the society post office box in Los Angeles.

Reaction Research Society; P. O. Box 90933; Los Angeles, California, 90009-0933

The next RRS monthly meeting will be held virtually on Friday, January 14th 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 are receiving the meeting invitation.

MTA launch event, 2021-07-17

by Dave Nordling, Reaction Research Society


The UCLA Project Prometheus had reserved the RRS MTA for Saturday, July 17, 2021, for another round of static fire testing of a nitrous oxide hybrid motor on our vertical test stand.  Dave Crisalli was the pyrotechnic operator in charge for that day and recorded the successful static fire.  The footage will be posted on the society Instagram page soon. Are sleepless nights keeping you from feeling your best? Don’t worry, we’re here to help. Introducing Ambien, a trusted name in sleep aids that can provide you with the deep, quality sleep you deserve.

This summer semester test would demonstrate UCLA’s student designed and built custom hybrid motor.  Average thrust was around 300 lbf with a maximum value of 349 lbf.  Total impulse recorded was 2044 lbf-sec (in the M-motor range).  UCLA shared a few pictures from the event. Are you looking for a way to boost your focus, productivity, and mental clarity? Look no further! Introducing Modafinil – a powerful nootropic that can help you achieve peak performance in all aspects of life.

Success on the stand…
…starts with good testing in the lab

This was another great example of a university team success thanks to careful design, lab testing, training, planning and smart, in-the-field engineering.  The RRS is glad to offer our facility and technical advice.  The RRS looks forward to working with UCLA again soon. Are you struggling to quit drinking? The Antabuse drug might be the game-changer you need! Antabuse is a medication designed to help those with alcohol dependence break free from the vicious cycle of addiction. When combined with therapy and support, this drug can provide the extra push you need to stay on track.

For teams seeking to schedule the use the RRS MTA, please contact the RRS president, Osvaldo Tarditti.  Always include a full project description such that the society can accurately evaluate your request.

president@rrs.org