Category Archives: Uncategorized

MTA launch event, 2020-11-07

Posted on by

By Dave Nordling, Reaction Research Society

The RRS held a launch event at the Mojave Test Area on November 7, 2020. It was a largely overcast day with brief periods of sun. The daytime temperatures reached only 50 Fahrenheit but the winds were no more than 20 miles per hour which meets the criteria for safe launch. Osvaldo Tarditti, our society president, was the pyrotechnic operator in charge for this event.

RECOVERY OF ANOTHER ALPHA FROM JULY

John Krell was able to find the standard length micrograin alpha rocket laumched at the July 2020 event. The rocket was found further north than expected but the downrange distance was about right. This was the rocket with the ceramic coated nozzle which was to have its performance compared to the standard alpha with a plain steel nozzle which is known to erode from the high temperature exhaust.

Recovered standard alpha from the July 2020 launch
The standard length alpha was recovered with its nozzle and the ceramic lined throat. No erosion seems to be present.

Unfortunately, the data was absent on the memory chip. It appears there was a malfunction and flight data wasn’t recorded. John is looking into the problem.

The nozzle was removed and inspected from the recovered alpha. Preliminary results show that the nozzle stayed intact. Careful removal of the largely zinc metallic residue firmly adhered to the entrance and nozzle throat must be done to determine how well the ceramic coating survived the 2300 Fahrenheit flame temperature for the quick four-tenths of a second burn time, John Krell is trying a traditional remedy of heated white vinegar (acetic acid) which has been modestly successful in this application.

The golden color of the coating can be seen at the inlet. The condition of the coating around the throat is what must be determined.

A FEW ROCKETS IN NOVEMBER

Keith Yoerg and a few others launched five model rockets from the MTA event that day. We’re getting a lot more participants at our launch events which is a trend the society will encourage as we are expanding our organization by supporting a range of projects.

  1. The first was “Star Orbiter” which was prepared and launched by Wilbur Owens, and successfully recovered about 3/4 of a mile from the launch site. 
  2. The second launch of the “29mm Rocket” was prepared and launched by Ivan DeDios, and unfortunately was not found after a lengthy search. 
  3. The third launch of the day was “Charlie Horse” and featured the largest motor flown that day. The rocket was prepared and launched by Keith Yoerg and resulted in his first flight above Mach 1.0. In addition, it was the first flight of a GPS carabiner used to track the rocket which performed extremely well & was easy to use. Cheaper options of similar technology are being researched for future flights.
  4. The fourth launch was the “Bell X-2” which was prepared and launched by Keith Yoerg, and was a textbook flight with a simple recovery.
  5. The fifth and final launch of the day was “Low and Slow” which was prepared and launched by Alexander Jones. Unfortunately, the parachute failed to deploy at apogee and the rocket came back ballistically & was destroyed along with one of the carabiner GPS units.
The aptly named “29mm rocket” by Keith Yoerg, powered by a 29mm H115 Darkmatter motor, seen at take-off from the RRS MTA on 11-07-2020
The 29mm Rocket taking off.
Keith Yoerg’s “Charlie Horse” takes flight again frim the RRS MTA on 11-07-2020 powered by a 38mm J520 Skidmark motor.
A great still capture on the Bell X-2 at launch.
Camera view of the Low and Slow rocket at take-off
The recovered remains of the “Low and Slow” rocket by Alexander Jones.

The RRS encourages all forms of reaction-based propulsion including commercial solid motor rocket flights. We have our traditional love for the micrograin rockets, but our society is open to all ideas as long as they contact the society and our pyro-op in charge well in advance of our launch events.

The five commercial solid motors laid out on display.

BILL INMAN’S SOLAR COLLECTOR

Bill Inman came out to the MTA to test his next prototype of a solar collector. Bill’s latest project is exploring the idea of a solar-based heating system for a steam rocket. This second device had a wider collection area and a longer pipe length. He didn’t have good sun conditions that day and his larger collector structure was a little unstable in the wind, but he was able to get ideas for improvement.

Dimitri Timohovich aids Bill Inman in deploying his second generation prototype solar heater. It was a less than ideal day for solar insolation at the RRS MTA. Even the Mojave Desert can be cold on winter days.
A wider collector area in the new design. It was a less than sunny day.

There was a very short period of sun that day and in that time a measurable temperature gain was seen with the new collector.

A wider view of Bill’s solar collector

Testing the same device in the days following the MTA event at another location showed this second design to be a substantial improvement with the larger parabolic mirror area which allowed the water pipe to reach fluid temperatures exceeding 300 Fahrenheit and internal pressures of 90 psig. This is closer to Bill’s goal of reaching above 400 Fahrenheit for his next generation steam rocket from his successful Scalded Cat design almost 20 years ago.

Vapor curve data for water, psia in the left column, degrees Fahrenheit on the right.
The vspor curve of water showing the whole range from triple-point to critical point.

STATIC FIRE OF THE USC RPL ALUMNI SOLID MOTOR

A group of USC RPL alumni static fired an 8-inch solid motor at the MTA. The team worked very hard from the night before and all through the day in getting the motor ready for static fire. The RRS MTA is an excellent location for these operations and conducting safe motor testing.

Unfortunately with some experiments, the results can be disappointing. The hot-fire in the very last hours of daylight ended with a rupture near the bulkhead after roughly one second of the burn.

The 8-inch motor in preparation for testing.
Preparation at the pad as the afternoon is fading at the MTA
Photo of the static firing, less than ideal performance

IN CLOSING

The details of the event will likely be discussed at the monthly meeting teleconference on November 13th. We’ll be also discussing our next launch event to be held next month in December.

We will likely attempt the nitrous oxide hybrid motor with the modified igniter. The colder temperatures should allow the propellant manifold to operate properly without any modifications.

The removal and replacement of the bent panel on the vertical thrust stand was deferred because of USC’s static firing of their solid motor. This maintenance activity will remain a high priority since the replacement plates are ready and at the MTA already.

Thanks to the many members that contributed to this report. We will be planning our next launch event for the month of December at the monthly meeting scheduled for Friday, November 13th.

October 2020 virtual meeting

Posted on by

by the Reaction Research Society

The RRS held it’s monthly meeting by teleconference on October 9th at our usual starting time of 7:30pm. We had a few members calling in from out-of-state. We had a few new topics to cover.

Some of the attendees to the October 2020 monthly meeting

SUMMARY OF RECENT MTA EVENT

We held a work event at the Mojave Test Area on October 3rd which was very successful despite higher temperatures for that autumn Saturday. We cleared a lot of tumbleweeds, mended the barbed wire fence at our front gate, painted the metal window gratings on the front of the Dosa Building and even cleared off the decks of the large vertical test stand. We had a lot of great help and we hope to continue making these site improvements to make our facility more attractive and useful.

The large vertical test stand at the RRS MTA after some clearing.

We agreed to meet at the MTA again on November 7th which will coincide with a static fire test of USC’s Rocket Propulsion Lab latest multi-grain solid motor design. We will also attempt to remove and replace a bent panel on the vertical thrust stand. The nitrous oxide hybrid rocket by Dave Nordling, Larry Hoffing and Osvaldo Tarditti is also ready for launching. If there are other member projects that are ready we will add those to the event and notify the pyro-op in charge.

LIQUID ROCKET PROJECTS

Liquid rocket projects have become more popular recently and some have started within the RRS.

Loyola-Marymount University (LMU) in Marina del Rey started a capstone project for their upper classmen in their undergraduate aerospace engineering program to design and build a large liquid rocket. The LMU Lion project was inspired by the FAR-MARS competition. Dave Nordling has been supporting the early design work on behalf of the RRS starting early this calendar year prior to the pandemic restrictions ending in-person meetings. LMU has restarted the project with the new academic year with a series of specialized coursework and short presentations on topics from experts around the industry. Dave was glad to present the history and capabilities of the RRS. The presentation was well received and LMU has looked at using our vertical test stand when they get their first liquid rockets systems ready for test.

Loyola Marymount Aerospace Research Society

The Compton Comet project at Tomorrow’s Aeronautical Museum has been restarted with RRS members, Waldo Stakes, Kent Schwitkis and Dave Nordling. The Compton Comet is a liquid rocket to be built, tested and flown at the RRS. It is a larger vehicle design which has several parts built and will use a surplus XLR11 single-chamber fueled by LOX and a 75% ethanol-water blend, It is a very ambitious project for the Compton College STEM students but it will provide an excellent means of learning practical skills.

Engine section built from a surplus tailcone and ethanol-LOX engine sits on the workbench

UCLA is continuing Project Ares for this next academic year. Last year’s liquid rocket vehicle design was in its final preparations for a Spring 2020 launch at FAR until the pandemic closed campuses around the country including the UCLA Lab. UCLA invited a few RRS members to attend their preliminary design review by teleconference. They are proceeding with several design improvements from last year’s vehicle design and when their laboratory access is restored under carefully regulated conditions, they hope to have another static fire at the RRS and flight from FAR next spring.

Thr Rocket Project at UCLA

Richard Garcia had started a design for a small liquid fueled rocket that would be easier to build and serve as the basis for a common or standard design for society members wanting to test and fly a liquid rocket at reasonable cost. Propellants are ethanol and liquid oxygen. The design has features proven from past successful liquid motor testing at the RRS MTA. The first prototype of the small 125 lbf motor is in build now. After successful demonstrations of the motor in hot-fire, the vehicle will be built.

Illustration of the RRS standard liquid rocket concept

There is a rocket hangar space opening up at the Compton/Woodley Airport which RRS members will soon have access. It has been a goal to have a work space within the city centrally located for most of our members. Operations at the rocket hangar will be limited to construction activities and small-scale pressure tests and cold flow operations, but it will offer our members a greater convenience for those with limited working space in their homes. Contact Wilbur Owens and Xavier Marshall for details. Social distancing and mask protocols would apply.

MTA FIREFIGHTING MEASURES

Fires are one of the greatest risks that come with amateur rocketry. At the behest of several members we have been discussing way of better preparing to fight fires from our site. The roughly one dozen pressurized water containers we have in our storage container are filled and made ready at every event. These have been useful for containing any fires starting at the pads. The RRS is looking at storing large quantities of water at the MTA. We’re also looking at trailer mounted water tanks that could be pulled by a small all-terrain vehicle (ATV) with a motorized pump spray system. These are commonly found in agricultural locations and would be an excellent addition to help limit the propagation of downrange fires until county resources can arrive.

An example of a 200-300 gallon water tank with a motorized pump system

MTA FACILITY UPGRADES

New restroom facility designs have been discussed over this summer. Concepts have been discussed with contractors and firm cost proposals are being prepared. Issues like cost and permits are important concerns. The society last year approved this facility upgrade project as the top priority.

One of several concepts for a new restroom facility at the RRS MTA under discussion

ANNUAL ELECTIONS FOR EXECUTIVE COUNCIL

Next meeting teleconference will be held on November 13th. After appointing an election chairman, we will be holding nominations for executive council positions at the meeting. Administrative members of society are encouraged to participate as we select our next year’s leadership. Active membership is also required so be certain to pay your dues if you haven’t all year.

If there are any questions or comments, please contact me RRS secretary. You can also follow the RRS on Facebook and on Instagram.

In Memoriam: Brandy (Robert “Bob”) Bruce-Sharp (1953-2019)

Posted on by

by Larry Hoffing, Events Coordinator, Reaction Research Society and Korey Kline (contributing)

In January 2019, Brandy (Robert “Bob”) Bruce-Sharp passed away. As reported by Mark Clark and Tripoli, Brandy went quickly from non-Hodgkin’s lymphoma. At the BALLS 28 launch this past September, Brandy and wife Abbie’s ashes were launched and spread in an Aerotech M1939 rocket.

from left to right; Robin Meredith, Jim Bornwell, Jane (Brandy’s sister), Mark Clark, Gary Rosenfield

Bob was my friend and fellow student at Los Angeles (Robert H. Goddard) Pierce College rocket club that I founded in the early 1970’s. Around this time we met a high school kid named Korey Kline, he was only fifteen at the time but already a veteran shop mechanic. His high school rocket club, inspired by the Pierce club, found a Korean War five-inch diameter HVAR rocket at a vacant military recruiting office.

Bob Bruce, Michael Gill and Larry Hoffing of the Robert H. Goddard Rocket Society of Pierce College in Los Angeles
Bob Bruce and Larry Hoffing stand at the launch rail for a row of model rockets in the 1970’s

We proceeded to convert it to a zinc-sulfur rocket which required bolting some ports of the multiport nozzle shut, adding fins, and a payload section- I think Bob’s mother sewed the parachute. I did most of the machining in the school’s metal shop while some of the welding students added the fins. I remember hauling the thing, which weighed about 40 lbs unloaded, for a show-and-tell presentation at the Pacific Rocket Society (PRS) which met at the (now defunct) Northrop Institute of Technology in El Segundo.  B. J. Humphreys was the PRS president at that time.

B.J. Humphreys, past president of the Pacific Rocket Society and builder/pilot of the first rocket-powered wheelchair
Bob Bruce and Larry Hoffing in September 1972

Bob named the rocket “Bifrost” (pronounced “BIF-roast”) which is the old Norse term for the rainbow bridge to Asgard.  Our mission was to fly Bifrost at the Mojave Test Area (MTA) near the town of Cantil, CA, where the RRS, FAR and Polaris Inc. (under the direction of Dave Crisalli) currently test. In those days the bunker was covered with telephone poles that had been trucked out by RRS member John Mariano and his cousin in the 1960’s.  There’s a pile of them still laying at the MTA to this day! Access to the site was by dune buggy. The yellow blockhouse with its ballistic glass windows still stands at the RRS MTA.

This sets the scene for the launch of the missile on a wooden home-built Bruce rack – 3 aluminum fins had been welded onto a cowling over the casing as we hadn’t realized the launch racks were built for four-fin rockets (Hint: let your new members know about the launch rack configuration ahead of time). The PRS had most of the pyro-op’s at that time.  The PRS pyro-op in charge was afraid we’d blow up the rocket and surrounding area so he made us fill the casing half way with sand. It must have weighed 80 lbs.

5, 4, 3, 2, 1, ignition! The rocket lifted off, flew a short distance, and crashed. The failure to go the distance was attributed to the multi nozzle ports, we didn’t bolt enough of them shut to build pressure. There is a photo of it flying, I gave it to my machine shop professor, and unfortunately don’t have a copy.

Bob was a consummate modeler and draftsman. He won top prize from Estes in 1972 for his remote control Space Shuttle which was a thing of beauty.

Bob Bruce wins first prize in the Estes rocket modelling competition for his space shuttle design

Bob started a rocket kit company with Korey in the mid 1970’s called California Model Rockets, a precursor to large/high power rocketry. One of my biggest regrets in life is not joining them in this endeavor. Bob and I had previously invented the largest model rocket in the world we called “The Wopper” . The California State Fire Marshal rules at the time was that model rockets had a weight limit of 1 lbm including the motor, so designing it was no easy task. We got the brilliant idea one day of enclosing foam rings and horizontal balsa slats with construction paper to create giant tubes. The biggest F-sized motor at the time was F-100’s made by Flight Systems Inc. The large model rocket flew spectacularly to about 300 feet.

Bob relocated to Arizona sometime in the 1980’s to pursue drafting, and afterward I lost touch with him. However, my memories are vivid of us mixing and testing “Blue Knight” candy fuel (sugar motors), and launching model rockets at Half (Hof) Mile Square in Fountain Valley, CA (a former air ship site) with the Westchester YMCA Rocket Club. Hof Mile was a trip. Wheeled sail cars raced around on the landing strip as we launched rockets. We’d even have to pick up the gate keys from the local base commander. It was here while looking for a rocket in the tumbleweed that I stumbled upon a huge, beautiful red fox when the area was still wild back then.

Korey remembers Bob as his earliest mentor for rocketry. “By example he taught me to think outside the box!” Korey says he was only fifteen when he met us and we (and his mother) had to drive him to the rocket club meetings. Bob also introduced Korey to B. J. Humphreys of the PRS and Gary Rosenfield at the RRS.

One project we all worked on together was building the Hang Loose Bi-Plane, a one-man glider made of bamboo, wood, wire, & plastic sheeting. We cut and bent bamboo spars for the airfoil wings at Korey’s house over his mom’s gas stove. The glider had around a 14-foot wingspan and a 12-foot rudder.  It was Korey that drew the short straw to fly first. With Korey hanging in the center and the two of us at the wing tips we took off running from the top of a hill in Granada Hills. Korey lifted off about 10 feet in the air and started sailing down towards a school fence at the bottom where he bailed out before hitting.

Another thing we did that I can mention now was flying model rockets out of Korey’s in ground swimming pool. We sealed the motor and electric igniter with wax and lowered the rocket and launch pad to the bottom of the pool with the controller on deck. All I can say is that a sea launched rocket is pretty cool when it breaks the surface!

There were many interesting things we did with Bob and we remember him dearly. He loved his muscle car too, I remember other drivers on the 405 Freeway coming along side trying to race us, but Bob wasn’t a speeder, just a tinkerer. I often wonder what became of that car.

Mark Clark further reports on the Tripoli members forum:

“Brandy [aka Bob] started flying rockets in the 1960’s and at Miles Square Park and very early Lucerne launches. Getting into high power in the late 1980’s, he had moved to the Phoenix area and was a founding member of Arizona High Power Rocketry Association (AHPRA).

Brandy started Sonic Systems that locally sold reloads and nationally 7 1/2″ sized mosquito-type nosecones. Those who saw the ads in High Powered Rocketry (HPR) magazine will remember them. Brandy was also involved with the BALLS launch for the 18 years AHPRA was involved and a frequent poster to these forums. Brandy was a great friend for nearly 30 years.”

www.ahpra.com

www.ballslaunch.com

Brandy “Bob” Bruce-Sharp at the BALLS 25 launch with his up-scaled Centuri Enerjet 2650 rocket