September 2018 meeting

The RRS held its monthly meeting for September 2018 this Friday, the 14th, at the Ken Nakaoka Community Center. We were displaced from our usual meeting room, but got the upstairs room F with the window view which was pretty nice. We were well attended, but got a very late start. Meetings begin at 7:30pm. There were several little events at the meeting which did not make the agenda.

Alastair Martin, Bill Behenna and Richard Garcia at the September 2018 meeting of the RRS

[X1]
The RRS was glad to welcome new student member, Bailey Cislowski. We had a short little social event at the end of the meeting which was a nice way to end the week.

Bailey Cislowski and RRS VP, Frank Miuccio

Also, the RRS was glad to re-welcome new members Wilbur Owens and Xavier Marshall. Wilbur had his first rite of passage in the RRS by taking his first standard alpha rocket. He’s looking forward to filling it with micrograin at the next launch event on October 27th. It will be one of many to come!

Xavier Marshall and Wilbur Owens; Wilbur gets his first RRS alpha

[X2]
Xavier invited the RRS to come tour the Experimental Aircraft Association’s local chapter at the Compton Airport. The EAA holds regular events including educational events with local kids.

Experimental Aircraft Association, Spirit of 96

Contact information for the local chapter of the Experimental Aircraft Association in Compton

[X3]
RRS member Alastair Martin is active with the Mars Society which just completed their 21st annual International Mars Society convention at the Pasadena Convention Center. If Alastair can oblige at our next RRS meeting, I have asked him to give the RRS a report on his experiences at the event.

Mars Society – home page

Besides film-making and photography, another one of Alastair’s talents is screen-printing on shirts. I recently had the RRS logo added to this bright-yellow shirt that I bought to better survive the hot Mojave desert climate of the RRS MTA. These bright-yellow “Ultra-Club” cool & dry shirts can be bought on Amazon in a variety of sizes besides the “XL” that I wear.

The RRS logo proudly worn on a fall afternoon

[X4]
I recently purchased a fly-away rail guide from Additive Aerospace. This company specializes in model rocketry parts including this simple clamp-on device that obviates the need for mounting rail buttons on the smaller rockets.

Additive Aerospace – fly-away rail guides

Additive Aerospace was nice enough to customize their standard 38mm design to fit the slightly smaller (1.25″ diameter) RRS standard alpha propellant tube. The fit check was perfect and the next step will be to attempt to launch an alpha from the 80-20 rail launcher we have.

Flyaway rail guide customized for an RRS standard alpha micrograin rocket is a good fit (and held closed by my hand).

Flyaway rail guide has two pairs of rail buttons to hold the rocket on the launch rail.

The flyaway rail guide is spring-loaded to open once the rocket travels up and off the launch rail, then simply falls away as the rocket speeds off

1.5-inch 80-20 aluminum rail extrusion, rail buttons are guided down this path on the rocket’s way up and away

12-foot aluminum 80-20 rail launcher, RRS MTA bunker in the background

[X5]
Osvaldo completed the cylinder piece of the ballistic evaluation motor (BEM) assembly that I designed for testing the burn rate of solid propellant samples. I forgot to bring the graphite nozzle pucks that Richard Garcia made for the assembly. Once the gaskets are fitted and the pressure transducer is checked out, we can begin to prepare 4-inch long samples of propellant into the 3/4-inch PVC tubes for which the BEM was designed to fire. This will be a useful tool in characterizing the AP/HTPB/Aluminum solid propellant batches that will be used in the prototypes of the SuperDosa project. Larry has already made a small batch of the RRS standard recipe solid propellant. Some of these first grains may be used in the propellant burn demonstration at the next RRS MTA launch event.

RRS BEM cylinder sits on top of the bottom plate, top plate in the background

[X6]
Thanks to Osvaldo again for his help with the two-stage alpha rocket that I designed. In this prototype, the payload tube was made longer for the possibility of a parachute recovery system for the upper stage. The 1-1/4″ PVC pipe was machined down to 1.600″ OD to fit inside of the standard alpha’s aluminum payload tube. The steel nozzle design, although simpler to make, may prove to be excessively heavy and throw off the mass balance of the rocket. The graphite nozzle design with its split retaining ring may be the better choice. More work is needed before attempting to fly this prototype design including completing the inter-stage timer circuit for deploying the in-line second stage motor in flight.

Two-stage RRS alpha rocket; second stage with a small AP/HTPB/Aluminum solid grain motor

[X7]
Since August, Osvaldo has made some progress in testing the load cell that will be used in the horizontal thrust stand. The bottle jack he used was tapped with an analog pressure gauge and the compression load into the load cell can be accurately measured. Despite some seal leakage problems with the older bottle jack, the results he and Matteo gathered from his data acquisition unit showed our S-type load cell matches the calibration sheet fairly well.

Load cell compression testing rig using a pressure gauge and a bottle jack

Finally, we got to some of the originally scheduled agenda topics:

[1]
Frank Miuccio gave an overview of the next educational event that had its first event of the series held today at Weigand Elementary school. This is the latest in the series of events we’ve had with the LAPD CSP program. The final event will the launch of the alpha rockets at the RRS MTA on October 27, 2018. Dave Crisalli will be our pyro-op at the event.

Osvaldo, Larry and Frank listen at the September 2018 meeting

[2]
We didn’t have another launch event planned yet for this year, but it’s always possible.

[3]
Richard Garcia gave a brief overview of his successful hot-fire test of his 1000-lbf kerosene-LOX motor on August 18, 2018. His pintle injector with an ablative chamber insert worked very well despite a leaking fitting at the LOX port. Some of the equipment did not work completely as hoped, but the overall test produced a stable thrust profile and clean cut-off. Richard put a lot of work into this first design which helps pave the way to the RRS standard liquid rocket project which will remain a regular topic with the RRS moving forward.

Richard Garcia after presenting his liquid rocket testing results; a proud day

Richard then moved into the details of integrating a liquid motor into a rocket body. Using commonly available parts and a few simply made connecting pieces, a simple but effective liquid rocket design can be made with a modest budget easily affordable to universities and individuals. This is still a work in progress, but the RRS is committed to bringing this project to fruition. We look forward to the next engine build which will likely be in a series of builds that will ultimately lead to the RRS standard liquid rocket design.

Richard’s Solidworks model showing both propellant and pressurant tanks plumbed into the rocket body

[4]
We had a very short discussion about the RRS expanding our roster of pyro-ops. Chris Kobel of ROC presented at our August meeting and gave a lot of practical advise on this subject.

Many of our next member “class” including myself have already written their rocket resumes to describe their experience with rocketry and have begun soliciting licensed pyro-ops for recommendation letters which is not a task to be taken lightly. Beyond the RRS regular and lifetime membership, the Rocketry Organization of California (ROC) was willing to help RRS members learn and earn their recommendation letters by attending and participating at events at ROC. The Friends of Amateur Rocketry (FAR) have also been very helpful to those of us who are aspiring to be new pyro-ops. The rocketry community is a small one and it is good to have the support of like-minded organizations to keep the membership across all societies safe, strong and active.

ROC holds monthly events on the 2nd Saturday of each month. I have been working on organizing a group of RRS members to go out to the next ROC event to get to know our smoke-and-fire sisters and brothers.

Rocketry Organization of California – Roctober event on Oct 13-14, 2018

To all of our membership interested in making this trip to the Lucerne Valley on October 13th, contact the RRS secretary. If we have a good number of people interested, we can make this a worthwhile trip. This trip would be on the Saturday immediately following the RRS meeting on that Friday night (Oct 12th). ROC will be holding an event with school kids, but if the RRS members bring their rocket resumes we may be able to have a conversation with the ROC leadership and get some advice and training. If we get a few members to ride out, I’ll contact ROC to let them know we’re coming. Please let me know by Friday, September 28th.

[IN CLOSING]
Next meeting of the RRS will be October 12th, which is always the 2nd Friday of the month. The quarterly update for the SuperDosa project will be part of the agenda as well as several items we did not cover in our agenda. All RRS members are welcome to make suggestions for discussion topics at future meetings. For those wanting to add topics, please let me know. I will post the preliminary agenda topics at the 1st of the next month on the RRS website Forum page.

As always, please keep your email and contact information up to date with the society. We’re glad to see so many new members and returning members. Even if you can’t make it to Gardena on a regular basis, just send us a line to say “hello” and tell us how you’re doing.

secretary@rrs.org

MTA launch event, 2018-07-21

The Reaction Research Society (RRS) held a launch event at our private Mojave Test Area (MTA) on Saturday, July 21, 2018. As I came into the site in the morning, I snapped a picture our front gate and the rough location which will be the site of our new sign to arrive very soon.

Follow that car. Turn left to go to the RRS.

Jim Gross was our pyro-op for the event. Many of us arrived early so Jim and the rest of the RRS had time to review the projects we wanted to hot-fire and fly if possible that day. Also, it was new members’, Michael Lunny and Bill Behenna’s first trip to the MTA. I think there is no better way to sell our membership on the benefits of the RRS than your first trip to the MTA. It worked for me!

Jim Gross, our pyro-op for the day

We were glad to host another group of students from the Watts area schools with the support of the Los Angeles Police Department’s (LAPD) Community Safety Partnership (CSP). This has become known as the “Rockets in the Projects” program.

LAPD CSP on Facebook

It was a challenge to hold this event in July in the Mojave desert, but the kids and staff seemed to withstand the 100-degree heat quite well with lots of water and bringing ice. We gave our safety briefing to everyone and explained the do’s and don’t’s for the event. RRS member, Matt Tarditti, was there helping with getting people shuttled around to the places necessary including moving our pyro-op, Jim, and his apprentice, (me) Dave Nordling, back and forth between the bunker and the alpha launch rails. Every step adds up in the heat and it’s wise to work as efficiently as you can. The heat ultimately got to me and I had to take a pause into the air conditioning of my truck. Despite my best efforts in hydration, the Mojave summer was still overwhelming. It is a feeling that many RRS members know all too well at some point in their time with the society at the MTA.

Matt was kind of enough to continue to assist Jim to complete the launch series with the alphas. Even, Jim Gross, who has been a resident of the high desert for many years, was having a tough time in the high temperatures and very low winds of that day. We had extremely low winds which made for great rocket launching weather, however with the building clouds above holding in a lot of the heat of the day, it was a real challenge for everyone to fight the stifling heat. The RRS conducts launch and test events at the MTA year-round, but some months are harder than others.

Matt Tarditti and Jim Gross under the hot July sun at the MTA

The LAPD CSP team does a great job in preparing these kids in the weeks ahead before this event. Often, this is many of the kids’ first trip into the Mojave desert. The stark beauty of the landscape hides the subtle dangers of snakes, spiders and the ever-present risk of heat stroke (even at 10:00 AM!). The RRS educational program is both fun and informative and through preparation everyone can make things safe. The kids were quite ready for the final event in the RRS educational program which is seeing their painted and assembled RRS standard alpha rockets take flight.

Michael Lunny, Frank Miuccio and Larry Hoffing stand among the students during the safety briefing at the George Dosa building

Our first goal of the event was to get the students’ rockets in the air so that those less experienced in the desert heat can go on home once the last one was complete. We had seven standard alphas to be launched, all painted by the students as their way to personalize their team’s flight. As always, the RRS reminds our classes that painting the bodies is nice, but since they return to the ground without a parachute, painting the fins in a bright and observable color matters the most when trying to find them on the desert floor. You’ll only have the tail fins sticking out of the ground when you find your rocket.

Seven alphas in the rack from Watts, plus Larry’s customized alpha with the wires sticking out of the payload tube

The kids paid careful attention to the time of flight which gives some data as to how well packed the alphas were. Two stopwatch measurements were made on each of the seven alpha flights. Impact was not heard on the seventh flight, so no data was taken. The results are somewhat consistent between the two readings and ranged between 36 and 39 seconds.

Time of flight measurements on six of the seven alphas flown on 07-21-2018

Ideal time of flight for an RRS standard alpha is thought to be between 35 and 42 seconds. This would indicate that Osvaldo’s rapid micrograin loading system is doing well to properly pack the propellant leading to good results.

Still shot from Michael Lunny’s video of the RRS standard alpha taking off

After the sequential launch of all seven alphas, it was unanimously decided not to let the kids hunt for their rockets downrange. The LAPD CSP team and the Watts kids went home after taking a picture under our arched sign. RRS member, Michael Lunny, shot a great video of one of the alpha launches from the bunker. I hope to get it posted to the RRS YouTube channel. We have a few micrograin rocket flights on YouTube, but we hope to add more content there soon. You’ll notice our name is not fully spelled out due to the old character limit when the account was made.

ReactionResearchSoc

Reaction Research Society on YouTube

After the Rockets in the Projects, this left the rest of the RRS membership to attempt the other projects we had ready for this launch day.

Richard Garcia brought his home-built rocket that is adapted for the sugar-KNO3 motor he tested at the 2018-06-02 event. He made three motors, one as a simple end-burner, the other two were cored. The plan was to fire conduct a static firing or two with his test motors and if all looked good fly the third motor in the rocket from the RRS rail launcher. “Rocket candy” as it is also called in amateur rocketry has been getting more popular at the RRS.

Richard Garcia stands in the assembly area by his golden rocket built for his custom sugar motor

Richard’s end-burner grain, 2018-07-21

Richard’s nozzle for his custom sugar motor

Richard’s two cored grains, sugar-KNO3 motors, 2018-07-21

Richard brought back his vertical static fire stand that bolts to the larger RRS frame. Although his thrust stand is not outfitted with a load cell (yet), it does give him the opportunity to safely secure his test motors and visually compare the results and time the burns.

Richard Garcia’s sugar motor held down to his vertical thrust stand for static fire

Larry Hoffing made a parachute system in his RRS standard alpha. His system was a little different from Osvaldo’s as he required a second firing line to light a delayed fuse for the parachute deployment system he put in. His son, Max, was there to help get things ready for flight as we included Larry and Osvaldo’s alphas into the launch sequence. Larry’s goal was to explore an older method of timing the deployment of his parachute by use of cannon fuse.

Larry’s alpha payload system being made ready for flight, 2018-07-21

Also, Larry had attached a signalling whistle on one of the fins. The ancient Chinese used to mount whistles on their rockets of war to strike fear in the hearts of their enemies as the rockets would scream to their target. It was Larry’s intent to add the element of sound not only for an impressive screeching launch off the rails, but also for better tracking of the rocket’s final descent to the ground. Although having a single whistle mounted to just one fin will impart a spin to the alpha, the flight will still be stable as proven on similar alpha flights. In the recent past, we have had success flying a larger, single keychain camera on the outside of a single fin while maintaining good flight stability despite the nauseating rapid spin seen in the footage from these externally mounted cameras.

Larry’s alpha with a whistle mechanically fastened to a single fin, 2018-07-21

Osvaldo inspects Larry’s alpha rocket in the launch rails with the second firing line connected for the fused payload timer

Unfortunately, Larry’s alpha had a problem at launch with the failure to light the micrograin rocket. Also, with this delay it was apparent that the parachute payload deployed way too early. The goal was to fire at 20 seconds in the flight and the fuse seemed to go at only 2 seconds popping the payload tube while the rocket stayed on the alpha rack. The two systems had to fire at nearly the same time but one system failed entirely and other went off too early.

After exploring all other failure modes with the firing circuit and procedures, it was confirmed that it was a bad electric match with a break in the wire. This was the first time I’ve seen an electric match fail in the three years I’ve been with the RRS, but it has been known to happen. With Larry’s whole payload system requiring repackaging, it was decided for expediency, just to remove Larry’s rocket from the launch rails, remove the nozzle and dump the micrograin propellant for a safe disposal burn on the ground. Larry will be able to re-use his alpha hardware, but it will have to wait for next launch.

Next was Osvaldo’s red colored alpha with his alpha with a parachute system built in it. Osvaldo made some minor improvements to the circuitry and this was to be his second flight. He also had a commercial telemetry package within his payload section.

Osvaldo’s red alpha with the breakwire switch to start the timer and the pull pin to arm the battery before walking away to the bunker to fire

Osvaldo’s alpha parachute system, break-wire secured to launch rail starts the internal timer

The first flight of his original parachute design for the alpha on 2018-06-02 was a complete success. Despite some slight overheating of the parachute from the black powder deployment charge on the initial flight, the rocket still coasted down very gently such that it laid neatly on the ground and a shovel wasn’t necessary for recovery.

The flight of Osvaldo’s second alpha was similarly successful in that the break-wire system and deployment mechanism operated properly, but the parachute itself failed to unfold due to tangling. The rocket’s descent even with the folded parachute was able to be spotted and Osvaldo recovered all pieces of his second flight.

Osvaldo inspects the second iteration of his alpha parachute system, 2018-07-21

Also, as an added bonus, Osvaldo was able to fit a commercial telemetry package to measure the flight acceleration. As the whole package survived in tact, it will be very interesting what the device was able to measure from within the tight confines of alpha payload tube near the nose. I hope he can present his results from the flight at the next meeting.

Osvaldo’s data package survives the flight, a little singed, and despite a folded parachute

There has been a lot of great progress in parachutes for the RRS standard alpha recently. Both Larry and Osvaldo have made great progress. With the persistent efforts of our RRS membership, I think its reasonable to expect that we could offer a standard alpha parachute package for our future events once we demonstrate a series of successful flights, settle on the design and figure the added cost.

Richard Garcia’s project having two successful static firings gave him confidence to try to mount and fly the third sugar motor. After having some initial integration problems and a rail button coming off, he was able to get his golden rocket ready for a launch on the rail launcher.

The rail launcher at the MTA is a great asset to the society. It has been used on several projects with good success, but it is a very heavy and sturdy device that requires two or three people to assemble and make ready. Also, the pin system that connects the rail to the stand fits very snugly and sometimes requires a lot of elbow grease and persuasion (perhaps with a rubber mallet) to get the right alignment of the holes. Despite the high heat, we managed to get things ready for Richard’s flight.

Rail piece with 12-foot, 80-20, 1515 aluminum rail

Launch rail base

Launch rail system ready to receive the rocket

Underslung launch rail system at the RRS MTA, assembled and ready for Richard’s flight, 2018-07-21

80-20 aluminum 1515 sized rail (1.5-inch) used as the guide for the launcher

Richard checks the manual for the telemetry package that he armed for flight.

Richard’s flight was on one hand a little underwhelming as his sugar motor did not produce a great deal of impulse, but it did manage to propel itself up and get clear of the launch rail before neatly turning back to the ground in a low-speed, but very steady and stable flight. Although his rocket only made it 50 feet downrange, it can be seen in the flight video that his rocket was stable throughout the whole low speed which is a testament to Richard’s good construction of a very aerodynamic and well-balanced vehicle.

The sugar motor doesn’t offer much impulse as it burns out shortly after clearing the launch rail

The rocket gently pitches over after burnout heading for the ground not very far downrange (the last good frame I have from my camera-phone)

After a perfect arc at its low apogee, the rocket turned back to the ground and landed almost perfectly on its nose. Despite the rough landing, the nosecone wasn’t damaged and many parts of the vehicle were similarly undamaged.

A very short, but extremely stable flight off the rails for Richard’s golden rocket with a custom sugar motor

Richard safes his payload system as he inspects the recovered rocket.

Richard will be working on increasing the impulse from his motor, but he can be very confident in his vehicle design. With a little rework on some of the parts, I think he should have a very impressive flight at the next launch event.

Osvaldo has put a lot of work into the horizontal thrust stand that I started. To be able to static fire an alpha rocket to measure the impulse, we have to accomplish two more things.

RRS horizontal thrust stand in need of an extension piece to stabilize an alpha for static fire

The first is to get better mechanical support for an RRS standard alpha to prevent sideways motions or “wagging” during firing. The stout, welded frame of the horizontal thrust stand fits just fine to the concrete slab foundation and is very secure, but the 3-foot length of an alpha could create quite a wicked angular load on the load cell. After Osvaldo and I had discussed a few design concepts, Osvaldo brought his design to the MTA. Given the time constraints of the launch events that came before and the stifling heat, we had no time to attempt a fit check of an alpha rocket in the thrust stand. The complete assembly will have to be fit checked at the next event. Osvaldo had also noticed that when the long alpha rocket is put into this short stand, the rocket doesn’t align very well with the beam. Some minor adjustments might be necessary to make sure the thrust vector is properly aligned with the axis through the load cell.

RRS horizontal thrust stand extension piece

The second thing is to try to calibrate the load cell to make sure the S-type load cell is still reasonably within its original factory calibration. Osvaldo brought in a home-built frame with a hydraulic jack and pressure gauge which can reasonably approximate a force by the pressure and piston area relationship. We didn’t have time to try this setup, but this device can be demonstrated at home if Osvaldo has time before the August 10th meeting.

hydraulic jack testing rig for verifying the S-type load cell calibration

hydraulic jack-based force tester with high pressure gauge attached

The horizontal thrust stand was not ready for the 2018-07-21 launch event due to a lack of cabling and a hardy computer to manage the data acquisition. Many of us are reluctant to bring our personal laptops to run the data acquisition in the abrasive sandy dry lake environment at the MTA. Chris Lujan at the July meeting talked about using a simple Arduino Raspberry Pi computer as a low-cost alternative to gathering and processing the data. Hopefully, the RRS will get a simple device for this purpose and have it programmed to take data from the load cell as we conduct our hot-fires from this horizontal thrust stand. There still is a lot of work to do in getting the horizontal thrust stand working. With more hard work, the RRS will have this project working soon, hopefully by the next launch event in the fall. We’ll post updates as this project advances.

One final note on the event is that the RRS will be posting a few things on Instagram once the secretary (me) has time to get things started. The RRS is brand new to Instagram so we hope to expand our presence here to better show everyone what we do. At first, the RRS executive council will have access to post photos at the events we attend for the RRS. We hope this presence on Instagram will generate more excitement and participation at events with the RRS.

Follow RRS on Instagram

The RRS will certainly discuss today’s launch event as a whole at the next meeting on Friday, August 10, 2018. There were a lot of great things we tried at the event, but there were also a lot of logistical things we can do better next time. Also, it would be a good time to review some of the material improvements that we ought to make at the MTA to better handle the projects we expect in the near future.

Please join us on August 10th!

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).