June 2018 meeting

The RRS held its monthly meeting for June 2018 on Friday the 8th at the Ken Nakaoka Community Center in Gardena. We were well-attended but got a late start on the agenda items. Wilbur Owens came back to see us again and has decided to become a member. Mohammed Daya who has joined the RRS also was able to stop by before the meeting started just to say “hello”. We were also glad to have Sam Austin back in town. Sam is a student at MIT interning at SpaceX this summer. He also paid us a visit both at the MTA on June 2nd and at the meeting tonight to discuss the liquid motor he built. There was lots to talk about at this June meeting between our outreach events and the hot fire testing.

RRS discussing things before the June 2018 meeting starts

A lot to talk about at the June 2018 meeting

[1] The RRS event at the Two-Bit STEAM Circus in Hawthorne was quite a success. The RRS was a bit short-handed, but we have great volunteers that stayed busy the whole time. The air rocket launcher was one of the big hits at the Circus event and we have been invited back for the next event in September. Frank made some improvements to the paper rocket template that is cut, folded and secured with tape to make the narrow tubes with attaching fins that comprise a paper rocket for the pneumatic launchers we have. The build process can be challenging for some, but it always is satisfying to see the finished product fly. The RRS is glad to have these events and we will surely do more.

Here’s some photos that Osvaldo took at the event.

RRS at the Two-Bit Circus STEAM Carnival in Hawthorne, CA. Frank works with kids to make the paper rockets for the RRS air launcher.

The air launcher is made ready to fire a paper rocket.

On a side note to this topic, USC is having a CRASH STEAM Carnival in 2019. We were invited to attend this year’s carnival, but the RRS is shorthanded and couldn’t support. We hope to expand our society to be able to come out for more events across the great city of Los Angeles. We’ll have more information on this event later.

[2] UCLA held their launch event at the MTA on June 2nd. The event was two-fold, it was the final project for the UCLA rocket propulsion class taught by Dr. Spearrin. It was also an opportunity for the UCLA Rocket Project team to static fire their hybrid motor. The event was a success for the class with the winds being nearly calm for most of the day. The small hobby rockets with F-sized motors reached good heights without being carried too far by the winds. Each had an altimeter and a hard-boiled egg as a payload that had to be safely recovered. Most were successful, but others not so much. A full write-up was done on an earlier RRS posting.

RRS MTA launch event – 2018/06/02

As a further note, UCLA was using a Jolly Logic Altimeter 3 model in their hobby rockets. These devices used by UCLA have proven to be very reliable and easy to use. The RRS will acquire some of these to fly in the payload tube of an alpha rocket to see what heights we reach in this micrograin mainstay rocket of our society.

Jolly Logic Altimeter 3 – manufacturer’s site

After UCLA’s static firings of their hybrid motor, the RRS flew an alpha rocket with a parachute system. This is a first in a long time. Osvaldo’s design had a safety switch to engage the battery only when the rocket is loaded to prevent it from getting depleted in waiting for launch. The parachute system also had a pull pin to start the timer circuit when the rocket lifted out of the rails. Osvaldo did bring another prototype of the alpha parachute system to discuss its features at the meeting, but we didn’t have enough time.

Osvaldo’s parachute deployment circuit that fits in a standard alpha rocket

After the June 7 launch event at the MTA, Osvaldo managed to find an RRS standard beta launched by UCLA last year. Although the payload segment sheared off in the extraction process, the nozzle is the precious part that can be cleaned up and reused.

RRS standard beta recovered from the RRS MTA; payload segment was not recovered

Osvaldo was also kind enough to make the adapter piece necessary for testing the RRS standard alpha second-stage solid motor I designed in the horizontal thrust stand at the next event. With this simple doubled-ended adapter that goes in place of the nose cone, the second stage motors once finished can fit into the load cell adapter and the RRS can get thrust measurements. Chris Lujan is working on a sucrose-KN solid grain and Larry Hoffing is working on an AP/HTPB/Aluminum motor grain. I have done the preliminary calculations for both and pressures should be appropriate for the 1.75″ aluminum payload tube. More discussion on this topic in future posts.

RRS alpha second-stage load cell adapter piece for the horizontal thrust stand. It goes in place of the nose cone.

[3] The next RRS build event with the LAPD CSP officers will be with another group of kids in the Jordan Downs housing projects of Watts. We’ll get started next week, 6/15/18, and run six educational sessions on Friday’s and Saturday’s until the launch event at the end of the program at RRS MTA. This will take place on July 21, 2018. This had to be re-scheduled due to the extreme heat predicted for the original date of July 7th.

The students will paint and assemble a set of RRS standard alpha rockets. More alpha rockets means more fun for our guests and also more opportunities for our RRS members to try payloads. It’s my hope we can demonstrate another one of Osvaldo’s parachute systems and fly an altimeter chip if we can secure one in time.

Richard Garcia said that he already has an Eggtimer Quark chip which has an altimeter. I had the chance to meet Cris Erving of Eggtimer Rocketry at the last Rocketry Organization of California (ROC) launch event in Lucerne Valley on June 9, 2018. I hope we can get an altimeter payload ready to fly in a standard alpha payload tube by the July 7th launch.

Eggtimer Rocketry

Rocketry Organization of California

[4] The new RRS membership card design has been finished. Many thanks to Bill Janczewski for pulling this together. We have had a few requests for membership cards from members and the RRS has agreed to produce these only on demand.

Jim Gross will be the first recipient of this new style of RRS membership card. This year’s design has the 75th anniversary watermark on it.

The new 75th anniversary RRS membership card

There was some general discussion about the payment of dues. Even as we are growing in membership in our society, the RRS has not been collecting dues on a regular basis. We’re content to primarily use the honor system and gentle reminders to our membership to pay their annual dues of $40 per year or student memberships at $20 per year. It is this small revenue that helps the RRS stay on top of our bills. Student memberships are good as many university projects can require multiple tests at the RRS MTA which is covered with signing the RRS indemnification form and paying membership dues to the RRS.

All membership applications must be sent to the RRS president and approved by the RRS executive council.
president@rrs.org

Payment of RRS dues ($40) and the added cost of a membership card ($5) can be done by check and through the Paypal donation button we have on the RRS.ORG website. It’s important to make a note on Paypal that you’re paying your Membership Dues. The extra price of $5 for membership cards is pretty small and compensate for the cost of low-volume production as most members may not opt to get one. To those desiring a membership card, please contact the RRS secretary.

secretary@rrs.org

For all of our regular membership, I had proposed that the RRS return to using membership cards which were used in the past in the society. Membership cards were issued to all members upon payment and re-payment of their annual dues. This provides a physical mechanism to verify that each member is in good standing with dues paid. The membership cards would have their name and an expiration date that says when annual dues must be paid again.

Although some felt the idea had merit, others felt that we should continue to have the council take the initiative to track payments and remind members to pay their dues as we have been doing. Since members join at different times in the year, this can get complicated but we will rely on members to stay on top of this.

It was a good discussion that also raised issues about what constitutes “active status” in RRS membership and our broader membership policies including corresponding membership for those who live outside of the Los Angeles area but want to remain a part of the RRS in some capacity. It was agreed to revisit this broader topic in the July 2018 meeting as some of our newer members may not be familiar with the past and current membership policies at the RRS.

[5] Sam Austin gave his presentation the Hercules Rocket Engine project at MIT. His liquid rocket propellants are LOX and kerosene. Sam was kind enough to bring his liquid motor that he is finishing. It’s a 500 lbf, 600 psi LOX-kerosene engine with an unlike impinging injector. His stainless steel chamber with a graphite nozzle insert ought to hold up to short burn durations. Everyone was able to inspect the injector, chamber and nozzle parts that Sam made at the MIT machine shop. The delicate work to get a clean injector pattern was impressive. He’ll be water flow testing the injector soon to verify that everything looks right.

The RRS recommended Specialized Coatings, a ceramic coating vendor in Huntington Beach, that we have used with success in the past on alpha and beta nozzles.

Specialized Coatings – Huntington Beach, CA

Sam Austin’s liquid motor nozzle with graphite throat

Sam Austin’s injector assembly for his liquid rocket

Sam is still working on the propellant feed system. He already has a pair of liquid carbon dioxide vessels that are of the right size. After safely removing the original valves and getting the rest of his control plumbing, he will hopefully have what he needs to conduct testing at the RRS MTA or at FAR next month in July 2018.

There were a few questions about different features of Sam’s liquid motor, but overall it looks like it should work. Sam is getting prepared to finish the propellant supply system for a static fire of this rocket motor. With luck, he should be able to get into hot-fire at the RRS MTA or FAR site next month and hopefully before he returns to MIT in the fall. We are glad that Sam has decided to join the RRS as a student member.

The RRS membership had a few suggestions for improvement and a few recommendation for low cost regulators, ball valves and relief valves that have been used in other amateur and professional projects.

[+1] We managed to talk about one bonus topic by showing the video from the vertical static fire of the vehicle-sized solid motor by Jack Oswald and his team at the RRS on Thursday, June 7th. The video clearly shows a nozzle failure after two seconds from start, but it seemed that there may have been grain fracture leading to a partial blockage of the nozzle and then the resulting pressure surge shattered the nozzle. We may upload the video to our YouTube channel once we ask Jack and his team. Hopefully, Osvaldo can extract a few still photos from his footage. I think some of those stills will show an impressive start followed by a change in the flow pattern and abrupt failure with ejecting fireballs of propellant that followed. The RRS works safely and are glad to have our own remote testing site like the MTA to do these larger projects.

Sam’s presentation was very engaging, but we ran out of time before the Community Center closed at 9:00PM. We did not address all of our main agenda items or some of those added at the last minute. We will roll these topics to the July 2018 meeting.

* Osvaldo’s alpha parachute system and the video of its launch on 6/2/2018 at the MTA
* Getting a sign at our first metal gate as you reach the MTA
* Saturday morning seminars for members and how to get those started
+ Richard’s progress with the RRS standard liquid rocket
+ Discussion about the 2019 symposium

+ We did agree to discuss the topic of RRS membership policy and what constitutes being an active member.
+ Also, on the meeting agenda for July 2018 is the quarterly update on the SuperDosa project. I hope to have something ready to present by July 13th.

If there is anything I have missed or misstated, please let me know:
secretary@rrs.org

Again, we will have another launch event at the MTA on July 21th with the LAPD CSP program and member projects to be discussed later.

The next monthly meeting will be July 13th at the same place and time (7:30PM).

May 2018 meeting

The RRS held our monthly meeting on May 11, 2018 at the Ken Nakaoka Community Center. We were well attended, but got a late start. After the reading of the treasury report, we started with the discussion of the agenda items. We were happy to be visited by Wilbur and Mel Owens and Harry Reid of the Compton area. They heard of our work with schools and have interest in rocketry projects. We hope to form some kind of partnership to help support like-minded Los Angeles area groups.

RRS president, Osvaldo Tarditti starts the May 2018 meeting

May 2018 meeting of the RRS gets underway

First on the agenda was discussing the results of the 75th anniversary symposium. We had a lot of great feedback and built a lot of good relationships with industry, universities, schools and private groups at the all-day event. We also discussed some of the lessons learned from the symposium and what worked well and what could have been done better. The RRS is very grateful to the many people who supported the RRS in making this event possible. The discussion then turned to discuss if the RRS will hold a 2019 symposium around the same time next year. After some initial discussion, the vote was postponed to next month’s meeting.

Discussion of the 2018 RRS symposium

Second on the agenda was the upcoming launch event at the MTA on June 2nd with UCLA. UCLA will launch 10 of their commercial rocket motors as the final part of the quarterly class that Dr. Spearrin has with his students. The RRS is glad to host the event and we also plan on launching at least two of our standard alpha rockets at the event.

Alpha rocket iso view

Also, the RRS horizontal thrust stand is nearly complete as Osvaldo and I confirmed the fit of the final load cell parts to the frame. Osvaldo brought the frame and I brought the load cell to the meeting. Everything looks ready to go for final fit up on the concrete pad at the MTA at the June 2nd launch event. Having the ability to make actual thrust curve measurements on the RRS standard alpha rockets will be very valuable to better understand the performance of this classic rocket. Much of what is known of the flight characteristics is based on old knowledge which could be somewhat theoretical. Getting new data will be a step in the right direction to reducing uncertainty.

RRS horizontal thrust stand sits on a dolly at the May 2018 meeting

payload tube adapter, S-type load cell and thrust stand adapter; fit check is complete

After some discussion of scheduling other possible launch events at the RRS MTA with Cal Poly Pomona and USC, we moved on to the next agenda item.

The third topic on the agenda was about the next educational event that the RRS will support with our partners in the LAPD CSP program. This summer program will be with Operation Progress in Watts. The first session will kick off on June 15th and the final launch event is planned for July 7, 2018.

Operation Progress – Los Angeles

The fourth topic on the agenda was regarding the RRS pyrotechnic operators manual that I am compiling for the society. The RRS uses licensed pyro-ops at our events and we are on a mission to expand our roster to better support the growing activities at the MTA. Osvaldo, Richard and I have begun the process of getting endorsement letters from our fellow pyro-ops and when our applications to the state of California’s Fire Marshall office are complete and received, we will take and pass the exam to become licensed. Having a society manual to capture this knowledge is not only useful to train new pyro-ops but it is beneficial for all of our society to have simple access to this important information.

RRS pyro-op manual and training guide

The fifth topic on the agenda was a discussion of RRS payloads. I have been pushing our society membership to think about and design payloads for the many RRS standard alpha rockets we launch. Although the payload tubes are very small (1.60″ inner diameter), there are many opportunities for flying ever-shrinking sensors in these payload volumes.

Larry brought a few commercially available sensor packages that he hopes to fly in beta rockets. Some of these devices are simple and powerful which have been used in high-powered model rocketry with a lot of success. Payloads such as these will certainly work well in RRS rockets as well. Beta rockets tend to be expensive, so it would be nice to have those that fit inside the alpha payload tubes (1.600″ OD or about 1-1/8″ square).

most payloads are too big for the alpha payload tubes; force-fitting doesn’t help

Example of pre-fabricated instrumentation package; clean, simple, but often too big

I have designed an in-line second stage for an RRS standard alpha. Osvaldo was kind enough to machine the interstage and second stage pieces that I described in last month’s meeting post. The second stage would have a solid motor poured into a PVC casing that fits within the standard alpha aluminum payload tube. The pieces fit very well together which is very encouraging. I took the interstage part home with me to integrate the umbilical port and wiring and work up the delay timer for the upper stage igniter.

RRS standard alpha interstage and second stage motor casing

The final topic on the agenda was an idea that Osvaldo had for more educational program at the RRS. The RRS has gotten to know many fine speakers in areas of professional and amateur rocketry. In the past, we have invited speakers at our meetings, but we often don’t have an appropriate amount of time to listen and discuss these topics at length. The idea put forth is that the RRS would hold Saturday morning presentations to our interested membership. The idea was well received and approved by the society. A list of speakers is being built and Osvaldo will try to schedule the first presentation in what we hope will become a long series. More details will be coming in future announcements.

One last topic wedged in as we were finishing was that the RRS will be attending the Two-Bit Circus event in Hawthorne, California, next Saturday, May 19, 2018. The Two-Bit Circus is a high-tech STEAM-based amusement park that started in downtown Los Angeles and is growing to include more areas of the city. The RRS is glad to be a part of it. The link to the event is below.

Two Bit Circus – Hawthorne 19-MAY-2018

The RRS will have a booth at the Two-Bit Circus and will be bringing our air launcher for small paper rockets. Frank built a new air launcher that’s a little cheaper, but just as powerful and fun to try. The RRS will have it available for demonstration near the basketball courts at the event.

Frank’s T-shaped air launcher

The RRS meeting concluded late at 9:25pm. We are grateful to the Ken Nakaoka Community Center for letting us stay beyond the 9pm closing time of the center. The RRS must try to begin our meetings on time so we can finish on time.

If there is anything I have missed or misstated, please let me know.
secretary@rrs.org

The next monthly meeting of the RRS will be June 8, 2018. Please join us.