July 12th 2013 Meeting Report

The July 12th meeting was quite an active one with about 13 in attendance and some interesting things to be shared. To accommodate Polaris this October the Launch may either be moved up to September or postponed to November. We’ve not officially set the date.

 

Larry Hoffing and his son did a great demonstration of polyurethane casting a nosecone. They had a mold of the nosecone and they poured in the polyurethanemix which was onepart resin and one part hardener by volume. They poured in some of the mix and rotated the mold as it hardened to make a layer of urethane around the walls of the mold. They did a few layers like this. The mold can be left like this to be hollow or as they did it can be filled the rest of the way to make a solid nosecone. The finished product can be sanded and it can be drilled out to make it hollow as well. The process is less precise than machining but significantly reduces tooling costs.It was discussed that the mold was originally from George Dosa for the Alpha rocket, and that Frank has some of the original forms from George Dosa for making the molds for casting nosecones.
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At the last meeting a few copies of the RRS beta plans went out. (I’ll eventually have a PDF of the plans on the new web site) With an impressive turnaround time Keven Tice came back this month with a finished rocket. He did an excellent job with the rocket and it looked great. He made some modifications to the design. He increased the diameter of the payload section, and he made a fin can instead of using straps. He also changed the fin shape from a parallelogram to a symmetric trapezoid.It total he spent around 40hrs building his beta. Since he changed the OD of the payload section he will have to make an adapter for the launcher. We look forward to seeing it fly at the next firing.

 

The 3D printed rocket competition has finished and I had to opportunity to share the end results and talk a little about the engine that we submitted. The winners will be announced around the end of July. If you want to know more you can see everything from us and the other competing teams at the contests site. http://www.openspaceuniversity.org/#!designs2/cun6

 
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Frank brought an RRS patch from the late 80’s and an RRS hat. He also brought and gave out some extra copies of an old RRS newsletter. (Volume 58, number 1, march 2001)  He also mentioned to me that from his stint as the secretary of the PRS (there equivalent of the RRS president) he has a copy of all the PRS newsletters that he wants to bring to the next meeting of the RRS so I can scan them for the RRS library.

 

I think the best treat of the meeting was something Frank brought to share. Frank showed a very interesting sort film featuring the RRS. Around the late 50’s early 60’s a college student from UCLA for a school film project create a short film originally recorded on 16mm film called “Whity” I won’t describe the whole thing here but it takes place at the MTA and Whity is a young boys pet mouse who’s is set to be launched in the nose cone of a large rocket when the boy has second thoughts about his pet’s safety.The film was well directed and well shot with believable and relatable characters and compelling story telling with a clear climax and resolution. The film felt like a little slice of history especially with every one dressed normally for the time. One of the characters also reminded me just a bit of Biff from “Back to the Future”

 

We were informed by John who was active in the society around that time about the concept for the rocket used in the film. It originated from the fact that typicalzinc-sulfur rockets seen at the RRS would have very high accelerations and would fly so fast that they would be very difficult to photograph and impossible to follow the rocket through its flight on film. To make a rocket more conducive to filming they made a very heavy rocket to slow its flight down so it could be filmed more easily. The rocket made use of a galvanized flue pipe for an outer skin and generous amount of wood on the inside.The crash as filmed was real and the parachute deployment was a special effects.

 

Frank has this film on DVD and I hope we can get it up on the new version on the web site. Since we don’t have contact with the original creator we may have to post it for members only. However most artists love to have their work seen, and I’m confident that if we got ahold of him they would be fine with making it publicly available.
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I also wanted to share these pictures I found of Microcosm’s Scorpius S-RM launch vehicle with 20,000lb of thrust being static tested at the MTA.

 

Microcosms Scorpius S-RM 20kengine sprite-pod The SR-XM Vehicle during final cold flow and hot fire test site.

 

-Richard Garcia

June 14th 2013 Meeting Report

Osvaldo returned to the MTA and found his rocket. (Along with a few other pieces of unidentified rockets) It looked like the parachute tangled on deployment possibly due to the shock cords being too short. His apogee detector broke and the main body tube was bent.

 

Osvaldo also brought the drawings to the RRS Beta and I’ll be scanning them soon, so now we can look forward to having those. Additionally he also brought the accompanying text to the RRS composite motor class, and I will also be scanning that to add to our RRS library.

 

The meeting was attended by an older one of our members John Mariano. He has been active in the past and he is currently working with the Endeavor exhibit at the California Science Center. He has noticed that over the past few years an interest in spaceflight and rocketry that he has not seen since the space race era. He is in an advantageous position to promote the RRS and he is interested in doing so and we discussed some of the possibilities.

 

John also brought a very interesting RRS artifact. It was a Copy of a small news article accompanied by an illustration. In 1948 the RRS proposed to build a 4 stage hydrogen oxygen rocket capable of delivering 100lb to orbit. This obviously never came to be, but I admire the ambition. I haven’t checked their numbers for their vehicle, but I have been working on designing a nano-satellite launcher for the 3D printed rocket engine contest and I do think a small launch vehicle delivering a payload on the order of 5 to 10 kg is doable at the extreme end of the amateur scale. (It would probably be something comparable to Copenhagen Suborbital’s second manned configuration, but with more stages.) He also mentioned some other interesting historical items from the RRS. There was an article about the RRS in a 1960’s edition of an encyclopedia. [Rocket Encyclopedia Illustrated – Herrick] There was also a RRS TV spot that John was in that aired on a local news station in the 1960’s. If you have anything like this from the RRS in your position, let’s get it convert it to a digital format so we can put it up on the website. Send me an email if you’re interested or need any help. (I had someone working at the Gardena recreational center make a copy of it for me but it was too large for him to get on one page so after I scan and edit it back into one image I’ll post it.)

 

We discussed an idea I had recently about trying to use an aqueous solution of potassium nitrate as a liquid oxidizer. I wasn’t sure how we could test if it would burn with a liquid fuel. If we just mixed some with ethanol and took a blow torch to it how we would know whether the ethanol was burning with the potassium nitrate solution or just atmospheric oxygen? Well someone clued me in on the fact that if the potassium nitrate was combusting there should be noticeable color change in the flame. I thought it was a good idea and I gave it a try the other day and I got positive results. I took a video and posted it to the RRS YouTube channel. I’ll be moving forward with a potassium nitrate solution/ethanol test stand engine design to see if this kind of propellant combination is a viable amateur alternative to liquid oxygen, nitrous oxide, Nitric acid and hydrogen peroxide. I plan to write an article about this and hopefully we’ll have a newsletter to put it in by then.

 

I’ve been working on the web site which Eric has set up in its own section of the server the site is currently on. It’s now under development and will not replace the main page until it’s more finished. Here is the address: https://rrs.org/ Any feedback positive or negative is welcome and appreciated.

 

We’re still on for an October 5th firing.

 

The next meeting will be July 12th at the Gardena Recreational Center, 1670 West 162nd Street Gardena, CA

 

3D printed metal rocket engine contest Update

I’d like to share how the 3D printed metal rocket engine contest is going:

The deadline was moved back to June 30th. The objective is to design an open source 3D printed (in metal) regenerativly cooled rocket engine for use on a nanosatellite launch vehicle (1-10kg payload). 3D printing in metal is an available technology and it has been demonstrated with regenerativly cooled rocket engines before. I’m submitting the design on a second stage LOX/Propane engine with around 800 lb of thrust. (It will be a sea level version for testing.)

I don’t mean to disparage the competition but as far as designing goes our team is pretty much stomping on them. I can say that because before you even look at any calculations for the engine just from a basic configuration standpoint all the other teams are non-starters in their current form. Although some show potential and I commend their effort. For example to make an engine like this you are going to need injectors, regenerative cooling channels, and film cooling, but we are the only team with all three. Only about 4 teams even have injectors designed at all, and only one other team looks like it could work. One team has what is supposed to be a pintle, but from the looks of it they’ve never seen one before. One team has oxidizer inlets but no fuel inlets. Only 2 other teams even have regenerative cooling channels, and we are the only team so far that has film cooling. We’re also the only team so far to mention how we will deal with some of the practical aspects of even just a static test, like LOX valves, flow metering and how to get a hold of cryogenic propellants. I’m no Wernher von Braun but these guys have a lot of catching up to do.
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However this advantage does not assure us we will win for two reasons. First, the design is oddly only worth 40% of the overall evaluation the other parts are 40% collaboration and 20% business plan. So we even if our competition has lousy rockets engines they could win simply by blathering to one another more and writing a convincing business plan. The second reason, which incidentally makes the first more troubling, is that while the judges have technical backgrounds they have no rocketry background that I am aware of, so I don’t know if they would know a good rocket engine if they saw one. One judge is known for having built an IEC fusor in high school. Another is an artist, a biologist, and a “space researcher” whatever that means. The third is the guy who designed the Segway (not the later CEO of the Segway company who fell to his death when he rode off a cliff on a Segway.) Although he has some legitimate engineering background (I mean other than the Segway) he is also the co-inventor of a pneumatic swat team cannon. That’s not a cannon used by swat team members to shoot at things, it’s a cannon that shoots swat team members out of it and onto roof tops, over walls, and to any other hard to reach place that you would like to have a swat team. I don’t know if he will recognize ‘realistic’ and ‘practical’ when he sees it. Maybe I should have gone with a rocket catapult to orbit instead.

This makes our job more difficult and winning uncertain. This means that in our design notes we also need to explain and justify a lot more than if we had judges that we knew were familiar with what it takes to make a liquid propellant rocket engine. We can’t simply state how much propellant we plan use for film cooling. We also need to let them know that if you don’t use film cooling at all you can expect a destructive engine failure. That way they are less likely to overlook our competitor’s flaws.
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I’m confident about our design, and I’m sure our business plan will be good as well, but I could use some help on the collaboration part. Just some back and forth comments on the collaboration site they want us to use should go a long way. Even if you know nothing about rockets the conversation would be beneficial and it would be appreciated.

The prize for winning is 5,000 dollars plus they will print the winning engine for free. For our current configuration at the vendor they intend to use that’s about another $5000 worth of 3D printing. If we win we plan to spend the money on things we would need for a static tests of the engine like a load cell, some tanks, helium, LOX ect. I think that if we won we might be able to have it ready for static testing at the October launch. If there is money left over we’ll put it towards a launch vehicle. (I intend to develop a scalable process that we could use to make pressure vessels from scratch.)

Win or lose, I want to turn some of the worked we’ve done on this into some RRS News articles, should we reboot the RRS News. I’ve done some programming for this that there may be some interest in sharing. I’m working on a program that sizes a launch vehicle based on payload, and another one that will give the basic chamber and nozzle configuration and do a basic thermal analysis. I also hope to work on a program that will analyze the rockets ascent trajectory. If you then take those 3 programs and put it all into an optimization scheme, like the evolutionary optimization program I wrote in college for turbopump design, you would have a launch vehicle design optimizer that can be used to help find the smallest and lowest cost launch vehicle configuration that could reasonably be pulled off. Neat huh!
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-Richard Garcia