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2:26 pm
June 8, 2010
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sampo
| | Espoo, Finland | |
| Member | posts 9 | |
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Post edited 2:48 pm – June 8, 2010 by sampo
Hi,
I happened to find this thread while googling for OpenRocket, and was intrigued by the project and the global collaboration.
I'm a rocketry enthusiast and programmer by heart. In my early days I coded a lot in C and a bit of assembly, but recently I've mainly switched to Java. I've studied physics and for my Master's thesis I developed the OpenRocket simulation software and its computational methods. The thesis itself is also available on the site under "Documentation".
I believe OpenRocket could be extended to realistically simulate 100K+ flights required in the first CSTART projects with relatively small effort. Later the framework might even be a suitable base for orbital simulations (though this would of course require a lot more coding and a custom GUI). More info on the development is in the thread linked above.
I'm also active in the (small) rocketry community in Finland. We recently launched a hybrid rocket that contained an active roll reduction system. An Arduino-based board measured the rocket's roll rate from the Earth's magnetic field and adjusted two fins to cancel out the roll. While others worked out the electronics, I developed the software for the controller in C. (Unfortunately in the last minute we taped an extra camera to the base of one fin, and that probably caused enough moment that after a few seconds the rocket started rolling even though the control fins were at a maximum cant against it.)
I've also got friends at Tampere University of Technology who have similar experience. They've participated for example in an ESA student program where their home-developed inertial measurement unit Itikka flew to 88K onboard a Rexus 5 rocket.
Cheers, Sampo
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9:04 pm
June 8, 2010
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J. Simmons
| | Dayton, OH, USA | |
| Member | posts 46 | |
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Wow, small internet. I just came across OpenRocket last week while doing some research for my dissertation and for Mach 30's Openeering Wiki. I have some other projects to work wrap up right now, but I am very excited to take a closer look at OpenRocket as soon as I get done with them. And the Arduino + Hybrid rocket project sounds like a lot of fun. Is there a web site or video for the project? I would love to learn more about it.
Can't wait to hear more from Finland,
-J. Simmons – Founder Mach 30 and Friend of CSTART
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Founder Mach 30, Inc. and Friend of CSTART
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9:17 pm
June 8, 2010
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Luke Maurits
| | Adelaide, Australia | |
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Hi Sampo,
Great to hear from you! As it turns out, we already have an active member in Finland, rpulkrabek (he's American but living and working in Finland), and as luck would have it, he is the CSTART member by far the most involved in our rocketry project, OHKLA, which sounds like the project that you would most be able to help out with if you are interested. This combined with your contacts in the small rocketry community in Finland make it seem possible that we might have the beginnings of a little physical hub for that project, which would be great! I will make sure rpulkrabek knows about this post.
Like J., I would be keen to see any websites associated with your Arduino rocket project. I also appreciate the Itikka link, since I am quite interested in inertial navigation.
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Main CLLARE workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java.
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11:37 pm
June 8, 2010
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rpulkrabek
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Moi,
As Luke mentioned, I am also living in Finland. I live in Hämeenlinna, to be more precise. This gives a great opportunity to collaborate on OHKLA, if you're willing. My degree is in the field of Mechanical Engineering. I have never actually made a large rocket before, so, I am relying on others with design decisions. I do, however, understand how to implement these decisions. For example, I can utilize FEA optimization techniques to determine the best nozzle geometry, but before we can finalize the nozzle, we need to know the rocket height and diameter, and before we know that, we need to know how much fuel and oxidizer is needed.
I am extremely excited to work on this. I would love to see OHKLA fly! I think we have the right members in CSTART to accomplish this. If you are willing, you will be a huge push to make this happen.
- Ryan
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12:16 am
June 9, 2010
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Luke Maurits
| | Adelaide, Australia | |
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rpulkrabek said:
we need to know the rocket height and diameter, and before we know that, we need to know how much fuel and oxidizer is needed.
Just to avoid giving the wrong idea about how much we know how to do: what we really need to know is what fuel and oxidiser to use. Once we know this, getting dimensions is quite easy. USOFS (or, just as well, OR) can help us estimate the required total delta-v to break the Karman line (IIRC this ended up being around 1500 m/s?). From this, getting fuel and oxidiser masses is a simple matter of knowing the Isp and optimal ratio, which are all easy to find. The knowing densities can give us dimensions, although the radius:length ratio would be a free parameter which we could probably use advice on.
With regards to oxidiser, I think there is fairly broad agreement in favour of N2O. As for fuel, we have been interested in paraffin in the past, although I for one am starting to reconsider this after reading up on the problems involved in (i) casting paraffin grains and (ii) having soft paraffin "slump" during high acceleration.
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Main CLLARE workgroups: Mission Planning, Navigation and Guidance. I do maths, physics, C, Python and Java.
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1:37 am
June 9, 2010
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sampo
| | Espoo, Finland | |
| Member | posts 9 | |
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Hi,
The reason we are currently concentrating on hybrids is Finnish legislation. It's a quite long and expensive process to get a solid rocket motor approved for sale in Finland compared to the market size, and we currently have only German-made A-D motors legally sold in Finland. Hybrids side-step this problem. Since they have the propellant and oxidizer separately, they do not contain pyrotechnical materials and are not subject to those laws.
We've flown two versions of "Haisunäätä" (Skunk) hybrid rocket, first a smaller one and the larger one with the roll reduction system. Both are built and customized from HyperLOC kits and fly with HyperTek engines. We're having our next launch at the beginning of July, though due to a quite high probability of landing in lakes we're only launching the smaller rocket. We also want to experiment with shear pins in the small scale before using them on the larger rocket (we've had problems with premature nose cone separation in both rockets).
Documentation is unfortunately something we'd really need to improve. There's a site in Finnish with some photos and info (http://haisunaata.avaruuteen.fi/), but it still doesn't contain much about the latest launch. A video from onboard the latest launch is at http://eddie.dy.fi/~sampo/pahk…..u_adhd.avi – during the first few seconds of flight you can see the rocket oscillating from side to side which is due to the roll control, after that it starts rolling.
We've also planned on setting up a stand for static tests and force measurement of hybrids, and testing some custom-made hybrid motors, mainly for fun. We've considered testing stuff like a birch-log motor (very Finnish) or a motor made from Gouda. From a more serious side I'm interested in testing the effect of the N2O temperature on the thrust curve, since this has been an issue during our winter launches.
The team (about 8 people) is working within the Finnish Astronautical Society, which has a 50 year old history of designing rockets and motors, but has been quite dormant for decades in this area. We're trying to revitalize that area now.
Ryan, we're having a lecture next Wednesday (the 16th) on building solid rocket motors given by an Iraqi-Syrian rocketry enthusiast who has recently moved to Finland. If you're interested and can come to Espoo you're really welcome. I can send more info if necessary.
Cheers, Sampo
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11:16 pm
June 9, 2010
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rpulkrabek
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Post edited 11:19 pm – June 9, 2010 by rpulkrabek
sampo said:
Ryan, we're having a lecture next Wednesday (the 16th) on building solid rocket motors given by an Iraqi-Syrian rocketry enthusiast who has recently moved to Finland. If you're interested and can come to Espoo you're really welcome. I can send more info if necessary.
Cheers, Sampo
I would really like to come. Unfortunately, I will be travelling to U.S. for work on the 14th and return on the 24th. I hope I can participate in future events, though.
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