Tag Archives: solid motor

MTA launch, 2019-04-06

Posted on by

Dave Nordling, Secretary, RRS.ORG

The Reaction Research Society (RRS) had another launch event at the Mojave Test Area (MTA). We had a nice cool day for the launch with a little wind. The winter seasonal rains left the land green which was a lovely change to the usual desert brown.

The RRS sign welcomes our guests to the MTA. The winter seasonal rains had turned the land green.
Desert flora in bloom downrange of the RRS MTA

We were pleased to be joined by California State Fire Marshal, Ramiro Rodriguez, who came out to see our amateur rocketry group in action. David Crisalli was our pyro-op for the event and I was glad to apprentice under him once again for this event.

RRS events coordinator, Larry Hoffing; RRS member and pyro-op, Dave Crisalli, California State Fire Marshal, Ramiro Rodriguez; and RRS secretary, Dave Nordling

Also joining us was the students at University of Southern California’s Rocket Propulsion Laboratory (USC RPL). The students had prepared a 6-inch solid motor for static fire test. They were demonstrating an improved carbon-phenolic nozzle design. They arrived the night before and made preparations all morning.

The name of USC’s 6-inch solid motor was “Poise”

USC still had a few more steps to go in their preparations before our other guests from Compton Elementary arrived. LAPD CSP and the RRS were glad to bring another class of young minds to see firsthand a rocket in flight. After all had arrived and settled, we held our safety briefing with our pyro-op, Dave Crisalli.

Students, LAPD officers, USC and the RRS gather in front of the George Dosa building for the safety briefing.
Ramiro relates practical advise on safety to the students of USC RPL.
Everyone safe in the observation bunker. We’re ready to launch.

We had six of our standard alphas made by the kids at Compton Elementary. This launch event is the final day in the educational sessions we do with local schools thanks to our partnership with the LAPD CSP.

5 of the 6 alphas sit in the rack; Osvaldo’s alpha with a parachute sits to the left.

We loaded each of the rockets in the numerical order they were labelled. Each team had their own color scheme to help make them unique. Reds and blues stand out well against the desert browns and green of the brush.

A very well timed shot of an RRS alpha just clearing the box rails.
A not-so well timed shot just a split-second too slow on the shutter.

After the last alpha from Compton Elementary, we launched Osvaldo’s alpha with a parachute recovery system packed in the payload tube. The parachute deployment system has a simple timer circuit that starts when a pin is pulled as the rocket speeds away off the rails. The red flagged plug in the photo is the safety pin to prevent accidental activation of the payload.

Osvaldo’s customized alpha rocket with a parachute recovery system (left in the photo).

Unfortunately, the parachute system didn’t deploy after launch. It’s possible that the timer deployed the parachute too early which the forward pressure against the payload tube may have held the system in place. The other possibility is the timer didn’t start at all. Either way, the recovery of Osvaldo’s rocket had to be done like all the others… with a shovel.

After the last of the alphas fired, LAPD CSP packed up Compton Elementary for the long ride home. The RRS is grateful for the chance to show young people the excitement of rocketry in the Mojave desert.

Dave Crisalli talks wtih USC as they made their solid motor ready for static fire. USC had several cameras ready to record the 11 second firing.
Dave oversees the careful installation of the igniter system into the core of the solid motor.

The USC RPL team was ready after waiting through our fusillade of micrograin alphas. With final preparations made and instrumentation checking out, the installation of the igniter package on the end of a long sacrificial stick was inserted to the proper depth. Standing back and bringing everyone to safety, USC began their countdown.

Still capture from video taken from the RRS MTA blockhouse. The motor ran full duration.
Post hot-fire inspection showed the carbon-phenolic nozzle still in tact.

USC had predicted a peak thrust of 800 lbf and a burn duration of 11 seconds. Actual burn time matched predictions, but thrust levels may have been short of expectations. USC was crunching the data as the RRS moved on to recovery of the alphas from down-range.

We were fortunate to find three of the alphas from the launch event. They were found north-west of the launch site which was unexpected. Another alpha from last year’s event was also found.

One of the three alphas we recovered later in the afternoon.

Osvaldo’s ratcheting extractor tool came in handy once again to avoid the back-breaking work of shoveling out an alpha once it’s found.

Securing the chain links in a circle near the nozzle throat gives the steel cable something to grasp as the ratchet progressively pulls the rocket from the ground in the same direction it entered.
Osvaldo’s alpha with a parachute was one of the alphas we recovered. Sadly, the parachute system did not deploy and the alpha returned ballistically with the parachute still packed inside.

The next RRS meeting will be Friday, April 12th, at the Ken Nakaoka Community Center in Gardena. This will be our last meeting before the 2019 RRS symposium on Saturday, April 27th. We’ll have more information posted here on RRS.ORG very soon.

June 2018 meeting

Posted on by

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 valtrex 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 http://pted.org/Propecia.php 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 (https://openoralhealth.org/ativan-lorazepam-without-a-prescription/) 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).

MTA launch event, 2018-06-07

Posted on by

The RRS held another smaller launch event at our private testing facility (MTA) in the Mojave desert on Thursday, June 7, 2018. This was a special event for the RRS members from the former Chaminade High School Rocketry group led by Jack Oswald. They have been working hard on their solid motor design. After a successful test series on a single 6-inch Bates grain, they moved up to a vehicle sized test with multiple six-inch grain modules installed. Dave Crisalli and Osvaldo Tarditti were available to assist in the loading and installation process making ready for testing. The vehicle static fire test was oriented nozzle up with a load cell at the bottom of the frame secured to the vertical test stand at the RRS MTA.

The static fire testing was for a 10,000 lbf-sec flight motor. The motor was expected to perform at 1500 psi, produce over 2+ tons (>4000 lbf) of peak thrust, and burn its 43 lbs of composite BATES grains in approximately 3 seconds.

Osvaldo had video of the firing where we got the still photos below. Osvaldo will bring the video footage to the meeting tomorrow on Friday, 6/8/2018, where everyone can see what may have happened.

Vertical static fire of a solid rocket motor at the RRS MTA, 06-07-2018

The solid motor started okay. The nozzle plume looked good for the first few moments.

Jack’s motor starts off just fine. A nice nozzle plume is evident.

Unfortunately, shortly after start, about 2 seconds into the burn, the pressure climbed substantially to 2300 psi causing a nozzle failure and subsequent burnout.

It looked like something disturbed the flow in the frame just before the huge fireball and the disintegration of the nozzle

After the nozzle failure, the solid motor spews chunks of fiery propellant until it fully burned out.

In the coming months, Jack’s team will make another motor reducing the Kn factor and significantly reinforcing the nozzle design to carry through with their plans of launching a boosted dart to an altitude of 150,000 feet sometime this year. This is still an impressive accomplishment and with some perseverance, success will come. More details to come as things proceed.

—

During the June 7th event, Osvaldo took some time to search down-range for rockets with his extractor tool. As luck would have it, he found one of the RRS standard beta rockets launched by UCLA in 2017. It was found about 3000 feet downrange which isn’t terribly far away. The winds must have been very favorable to allow the beta to plant itself much closer to the launch site. From the photo, you can see that this RRS beta had a fin-can type of fixture at the tail which is easier to manufacture.

Beta planted 3000 feet downrange from the launch rails, straight west more or less

The convenience of pulling the rocket straight from the ground with the manual winch is tremendous, but the method often shears off the payload tube in the hole. Shoveling does have the advantage of removing most if not all of the parts if one is inclined to spend the hours necessary to dig four feet below the surface. The payload tube from the beta unfortunately was not extracted with the propellant tube. Osvaldo will bring the beta to show everyone at the meeting tomorrow.

Osvaldo lifts the beta rocket from out of the desert floor

We’ll have our monthly meeting (every 2nd Friday of the month) on June 8th at 7:30PM sharp. Please stop in!