tag:blogger.com,1999:blog-23795730806763805482024-03-04T20:04:15.125-08:00Australian Rocket CompanyMitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.comBlogger22125tag:blogger.com,1999:blog-2379573080676380548.post-79329071667750915262017-10-11T05:09:00.001-07:002017-10-11T05:09:53.411-07:00Optimising with SNOPT<div dir="ltr" style="text-align: left;" trbidi="on">
I am trying to get the SNOPT program installed and working, so I can run rocket trajectory optimisations such as this<br />
<br />
I found that there is a download available for the student snopt from <a href="http://www.netlib.org/" target="_blank">Netlib</a>. This is version 7.5-1.2 from June 2015.<br />
<br />
<br />
$ ./snopt_macos --version<br />
Student SNOPT 7.5-1.2 (Jun 2015) (Darwin 10.8.0 x86_32), driver(20150821), ASL(20160325)<br />
<br />
<br />
Code can also be downloaded from <a href="http://ftp.uni-bayreuth.de/math/netlib/ampl/solvers/" target="_blank">http://ftp.uni-bayreuth.de/math/netlib/ampl/solvers/</a> although this will need compiling, and not sure which versions this is. It appears to be verison 7.3 or later from the release notes.</div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-63607697920214267412016-06-20T16:38:00.001-07:002016-06-20T16:38:33.925-07:00Woodworking Books Library<div dir="ltr" style="text-align: left;" trbidi="on">
<h3 style="text-align: left;">
Physical Books</h3>
Making Antique Furniture Reproductions - Franklin H Gottshall<br />
Shop Drawings of Shaker Furniture - 1,2,3 - Handberg<br />
<br />
<h3 style="text-align: left;">
Kindle Books</h3>
Making Authentic Craftsman Furniture - Gustav Stickley<br />
Making Furniture Masterpieces - Franklin H Gottshall<br />
Making uthentic Shaker Furniture - John G Shea<br />
<br /></div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-54971670386498344132015-09-20T18:48:00.000-07:002015-09-20T19:07:02.277-07:00Survival Library Books<div dir="ltr" style="text-align: left;" trbidi="on">
The aim is to collect a list of all the useful books, particularly the technical ones, or websites which have the information necessary if the Internet and life as we know it stops. There are other sites which have books out of copyright, however so much has changed in the last 100 years that I feel it is necessary to have modern books to keep up to date.<br />
<br />
<br />
<h2 style="text-align: left;">
Workshop Manuals</h2>
<ol style="text-align: left;">
<li>David Gingery Workshop Manuals (7 books)</li>
<li><span class="a-size-large" id="productTitle">507 Mechanical Movements: Mechanisms and Devices</span><span class="a-size-large" id="productTitle"> </span></li>
<li><div class="a-size-large a-spacing-none" id="title">
</div>
<div class="a-size-large a-spacing-none" id="title">
</div>
<div class="a-size-large a-spacing-none" id="title">
</div>
<div class="a-size-large a-spacing-none" id="title">
</div>
<div class="a-size-large a-spacing-none" id="title">
<span class="a-size-large" id="productTitle"></span><span class="a-size-large" id="productTitle">Basic Machines and How They Work (Navy Education)</span><span class="a-size-large" id="productTitle"> </span></div>
<div class="a-size-large a-spacing-none" id="title">
<span class="a-size-large" id="productTitle">1800 Mechanical Movements, Devices and Appliances</span><br />
<div class="a-section a-spacing-none">
<h1 class="a-size-large a-spacing-none" id="title">
<span class="a-size-large" id="productTitle">Mechanisms and Mechanical Devices Sourcebook, 5th Edition</span>
<span class="a-size-medium a-color-secondary a-text-normal">Kindle Edition</span>
</h1>
</div>
<div class="a-section a-spacing-micro bylineHidden feature" id="byline">
by
<span class="author notFaded" data-width="">
<span class="a-declarative" data-a-popover="{"name":"contributor-info-B001H6QPKU","position":"triggerBottom","allowLinkDefault":"true"}" data-action="a-popover">
<a class="a-link-normal contributorNameID" data-asin="B001H6QPKU" href="http://www.amazon.com/Neil-Sclater/e/B001H6QPKU/ref=dp_byline_cont_ebooks_1">Neil Sclater</a></span><span class="contribution"><span class="a-color-secondary"></span>
</span>
</span>
</div>
</div>
<div class="a-size-large a-spacing-none" id="title">
<span class="a-size-large" id="productTitle"> </span><span class="a-size-large" id="productTitle"> </span>
</div>
<div class="a-size-large a-spacing-none" id="title">
<br /></div>
</li>
</ol>
<br /></div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-40435545974312883682013-10-02T20:41:00.002-07:002013-10-02T20:41:54.518-07:00Saddleback Large Thin Briefcase in Tobacco brown<div dir="ltr" style="text-align: left;" trbidi="on">
<h4 style="text-align: left;">
<span style="font-weight: normal;">I recently bought the Saddleback Large Thin Briefcase in the tobacco brown colour, and it arrived yesterday (2nd October 2013). The leather is amazing and it is an all around beautiful bag. The only problem is that it looks too big for my body size. I am 5'9 (178cm) and 150lb (70kg). Although I wanted the larger size to have the best fit for a 15" Macbook Pro I am just not tall/heavy enough for the large size to actually look good on me.</span><br />
<span style="font-weight: normal;"><br /></span>
<span style="font-weight: normal;">I am therefore trying to sell this beautiful bag. Currently it is listed on Gumtree.com.au at <a href="http://www.gumtree.com.au/m-my-ad.html?adId=1028939378" target="_blank">Saddleback Large Thin Briefcase - Tobacco</a></span><br />
<span style="font-weight: normal;"><br /></span>
<span style="font-weight: normal;">The briefcase has never been used, and is still in the original plastic wrapping. I have taken it out to have a look only. </span><span style="font-weight: normal;">Saddleback briefcases are considered to be one of the best made leather briefcases on the market. With a 100 year warranty (even if you weren't the original purchaser) these are made to last. No zippers or snaps which will break, just high quality leather with double stitching and tough pigskin lining. These are the briefcases that will last you a lifetime. The leather is the best quality full grain leather, it looks and smells fantastic. The bags will look even better in a few years time, just have a look at some of the pictures online. Also comes with the free keychain that was included in the box. </span><br />
<span style="font-weight: normal;"><br /></span>
<u>Exterior: </u><br />
<span style="font-weight: normal;">16 ¾” W x 11 ½” H x 4 ½” D </span><br />
<span style="font-weight: normal;">425mm W x 290mm H x 115mm D </span><br />
<span style="font-weight: normal;"><br /></span>
<u>Interior: </u><br />
<span style="font-weight: normal;">15 ¾” W x 11 ¾” H x 4” D </span><br />
<span style="font-weight: normal;">400mm W x 300mm H x 100mm D </span><br />
<span style="font-weight: normal;"><br /></span>
<span style="font-weight: normal;">A Review from <a href="http://www.primermagazine.com/2011/spend/saddleback-leather-thin-briefcase" target="_blank">Primer Magazine</a></span><br />
<br />
<span style="font-weight: normal;">The full product deatils are on the <a href="http://www.saddlebackleather.com/briefcasethin?sc=8&category=301406" target="_blank">Saddleback Leather</a> site.</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9Ksw48iQsc7aHPwBhfdo63fVahsiiZVsQfOwazCqqB8cJ3BBSEYxyyWv2mWjy48ZxkBwAlZpJS2RkC9nt8iDHtSC09f-Sz3UXPOW4T9WuYT24Y8UE1sGyGKwb5iSipjWkp3jwIqJ7qbKr/s1600/Lge_Thin_New_P1.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9Ksw48iQsc7aHPwBhfdo63fVahsiiZVsQfOwazCqqB8cJ3BBSEYxyyWv2mWjy48ZxkBwAlZpJS2RkC9nt8iDHtSC09f-Sz3UXPOW4T9WuYT24Y8UE1sGyGKwb5iSipjWkp3jwIqJ7qbKr/s320/Lge_Thin_New_P1.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Product Picture from Saddleback</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhh4zaLjumlFbUqAFxS91ozTc_OeF-8rFjTH6GdLZBH5odKBhFIXnzR9ocX6v0q2CSJrwRuID5pauTP2hJ1qT-LVHG5Lt7W6meZO8m5k8xz4oIGcG14QFGYoOvIU-VjLYfU-0hfkIIbvWJ2/s1600/Lge_Thin_New_Inside.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhh4zaLjumlFbUqAFxS91ozTc_OeF-8rFjTH6GdLZBH5odKBhFIXnzR9ocX6v0q2CSJrwRuID5pauTP2hJ1qT-LVHG5Lt7W6meZO8m5k8xz4oIGcG14QFGYoOvIU-VjLYfU-0hfkIIbvWJ2/s320/Lge_Thin_New_Inside.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Product Picture of interior from Saddleback</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMg2OCtGb5ROLHBl6TmgNbg7eyWLuKlnwYVcFCx4tLCLPOKMn0NanMy6D2lTG5KFDDHavON936Q95urt0qXyNKZvJolIJw9qobHXNqQgEfWVRYsJGyq5-XP15iLUUqI8CEnuU7PXlgkSS4/s1600/Lge_Thin_Front.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="213" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMg2OCtGb5ROLHBl6TmgNbg7eyWLuKlnwYVcFCx4tLCLPOKMn0NanMy6D2lTG5KFDDHavON936Q95urt0qXyNKZvJolIJw9qobHXNqQgEfWVRYsJGyq5-XP15iLUUqI8CEnuU7PXlgkSS4/s320/Lge_Thin_Front.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Front view</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjbtq6CttQIB647GFqwsnZfrsGhBmhVs7NDk3nZLjWidpVl-5GYJb9flqyQfzlI15JWtU9YEatAvlYSQn0irsNyWkH4ZPR6cFrBbSkfNlvUcOWXYPbeuFl83bcHCHync3MeH9k2XT_gz6E/s1600/Lge_Thin_Back_Side.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="213" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjbtq6CttQIB647GFqwsnZfrsGhBmhVs7NDk3nZLjWidpVl-5GYJb9flqyQfzlI15JWtU9YEatAvlYSQn0irsNyWkH4ZPR6cFrBbSkfNlvUcOWXYPbeuFl83bcHCHync3MeH9k2XT_gz6E/s320/Lge_Thin_Back_Side.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Side and back view</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">Back view</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">Front view with measuring tape for scale</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">Saddleback logo on the front strap</td></tr>
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<br />
<span style="font-weight: normal;">The first two photos are from the Saddleback website. About two days ago (30th Sept 2013) they updated the tobacco colour leather, so what you see on the website now is slightly different, although all the other details such as size are the same. The other pictures are of the actual bag. I will sell it for $450.</span><br />
<span style="font-weight: normal;"><br /></span>
<span style="font-weight: normal;">Can pick it up from me, or arrange to meet me somewhere and I can drop it off after work.</span></h4>
</div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com2tag:blogger.com,1999:blog-2379573080676380548.post-22839540130443158672013-04-18T05:09:00.003-07:002013-04-18T05:09:29.598-07:00GPOPS - Optimisation SoftwareOne of the major things missing from the CADAC4 software is the ability to calculate the optimum trajectory. This comes down to finding the optimal path given the known initial conditions (position and velocity) and the desired final conditions (orbital velocity and height). I have been doing a bit of reading of research papers dealing with this problem, however making the leap from the theory to the actual coding has been difficult. Mainly because I am not good enough at the maths to understand it properly.<br />
<br />
Since it is unlikely that I will ever be able to code this myself, I did some more searching for an existing solution. I found the GPOPS software, which is a Matlab program for solving these sort of optimal control problems. Although there is still a lot to learn, one of the examples is a rocket launch with multiple stages. My aim is to learn this example and then create a clone of it with the DH-1 details. The input details will be determined by running CADAC4 and getting the velocity and position at stage separation. These will then be the inputs for the GPOPS run to determine the optimal path. It will be interesting to see how close the figures are to the book numbers! I will post some diagrams when I have gotten this done.<br />
<br />
<h3>
Running GPOPS </h3>
<ol>
<li>GPOPS can be downloaded from <a href="http://sourceforge.net/projects/gpops/" target="_blank">Sourceforge</a>. I am running it under Matlab R2009b under Ubuntu.</li>
<li>Ensure that you have a large amount of swap space. I have had to increase mine to 16Gb.</li>
<li>Run the 'gpopsSetup' command from the unzipped directory.</li>
<li>Change to the 'examples/launch' directory and run 'launchMain' to start the run.</li>
</ol>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-74301386432992327622013-04-10T01:19:00.001-07:002013-04-10T01:19:40.397-07:00Developement Pathway to the DH-1<div class="MsoNormal">
The two biggest barriers to getting the funding for building the DH-1 are:</div>
<div class="MsoNormal">
<br /></div>
<ol>
<li>The acceptance of simple engineering in the rocket area</li>
<li>Getting over he believability hump</li>
</ol>
<div class="MsoNormal">
<br /></div>
<h3 class="MsoNormal">
Simple Engineering</h3>
<div class="MsoNormal">
The
simple engineering approach is to cut back all the unnecessarily
complex approaches to aerospace engineering and focus on building things
that will work reliably. Accept the compromises where they need to be
made instead getting bogged down trying to develope new technology to
solve all the aspects of a problem. Focusing on the achievability of the
whole mission, not any single piece of technology. An example of this
is the design of the U2 spyplane with its unstable flight
characteristics and unusual landing gear, but over the last 50 years it
has proven to be one of the most effective ways of doing that high
altitude spy missions. Being able to accept the compromises in design to
achieve the mission is a big mental hurdle.</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Instead
of having the design drivers being low weight and maximum efficiency,
have the design drivers as being the simplest approach which will enable
to job to get done. This means that instead of trying to build the
space shuttle, with its incredible complexity, we instead try to build a
DC-3. Overengineering the first vehicle is not something to be avoided
but encouraged! We simply dont know what the working environment will be
for a reusable launch vehicle which operates on a daily or weekly
basis. We therefore need to focus on getting a vehicle which will
survive for a sufficiently long number of launches to prove the concept.
The very first DH-1 will likely have a very small or zero payload. But
it will truly be reusable, and the experience gained will be invaluable.</div>
<div class="MsoNormal">
<br /></div>
<h3 class="MsoNormal">
The Believability Hump</h3>
<div class="MsoNormal">
The
second barrier is the believabily hump. Most people will not be able to
understand how simple and robust the DH-1 concept is until they see it
in operation. Therefore we need to have a way of starting small while
still keeping all the important aspects of the design. One idea which I
have recently found is to first create a smaller reusable sounding
rocket. This would be a single stage vehicle that combines both the
first and second stage ideas. There is a very good article by Yoshifumi</div>
<div class="MsoNormal">
Inatani over at <a href="http://www.spacefuture.com/" target="_blank">www.spacefuture.com</a>
detailing the design of a reusable VTOVL design and the emphasis on
reliable operability. Although it doesnt have the capability to reach
orbital velocity it can still reach an altitude of over 300 km.</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
This
rocket also has a payload of 100kg, which is a lot more than most
sounding rockets, with a much larger payload bay volume as well! Because
it is reusable with quick turnaround times it would greatly reduce the
whole cycle of developing an experiment through to launching. I feel
that if this cycle can be reduced to months instead of years then it
will allow a lot more interesting work to be done. Instead of having a
sounding rocket launch be a once in an education experience, it could be
a once a semester type of experience. Most importantly it would show
that the model of having much simpler yet more robust launch vehicles
being turned around rapidly is a significant advantage.</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
I
would envisage a small single stage reusable sounding rocket such as
this being built for a couple of million dollars. The aim would be to
assemble a small team of engineers to design and build this, operating
on the X plane development model. This would enable the software and
analysis to be done in smaller easier steps and verify the concept
before too much money needs to be spent. This experience would then
enable better engineering and design choices to be made once the full
DH-1 developement occurs.</div>
<div class="MsoNormal">
<br /></div>
<h3 class="MsoNormal">
The Side Note</h3>
<div class="MsoNormal">
There
is some great video footage from onboard the <a href="http://www.youtube.com/watch?v=VNtR5HIL3FM" target="_blank">Armadillo Aerospace Stiga</a>
sounding rocket. An interesting look
at what the world is like from 40km up!</div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Another talk which is interesting is by Kim Ennico (SETI), talking about <a href="http://www.youtube.com/watch?v=cN-odv0Ea5Q" target="_blank">Commercial Suborbital Spaceflight.</a></div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-83327573099666752002013-03-28T04:50:00.000-07:002013-03-28T05:12:00.573-07:00Running CADAC4 for the DH-1This post is the documentation for running the CADAC4 program with the DH1 modules and inputs. All the software has been uploaded to a Google Code project called <a href="https://code.google.com/p/cadac4-dh1/" target="_blank">cadac4-dh1</a>. The initial checkin was the version that I was running from my USB stick under windows, using the gfortran compiler.<br />
<br />
The second checkin was the code that I had under Linux, which can be compiled into an executable using the gfortran compiler.<br />
<br />
To compile the main DH1 program, execute 'gfortran CADX3.FOR UTL3.FOR R3_MODULE.FOR'<br />
<br />
The output will be an 'a.out' executable which should be renamed as 'DH1'. Running this program then reads the input files and calculates the TRAJ.ASC outputs. Refer to the CADAC4 documentation for full details.<br />
<br />
Because I am not certain that compiling the Utility files is working correctly, I have also put the Windows/DOS versions of the utilities (CADIN3.exe etc) into a directory called DOS.<br />
<br />
The output files can be plotted in Matlab. Start by opening Matlab in an X session:<br />
<br />
/usr/local/Matlab/bin/matlab<br />
<br />
First edit the TRAJ.ASC to remove all the headers and column names, t<br />
hen change directory to the DH1 code, and execute the 'PlotGraph.m' script. This will generate a graph similar to the one shown.<br />
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1ZLLx3qiHtjLlNI-NrZdhiOS0t9g7kUB11R824D9x_vAATZdyAq-ng69FgBwGJmWSuJ79sigFoAun-G67dULYcKIhMhMx0NCMtJh2Ra2hv0omp72gGhcKW8laSijd_ciqgH0SSsiyfG6F/s1600/Altitude_Plot.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1ZLLx3qiHtjLlNI-NrZdhiOS0t9g7kUB11R824D9x_vAATZdyAq-ng69FgBwGJmWSuJ79sigFoAun-G67dULYcKIhMhMx0NCMtJh2Ra2hv0omp72gGhcKW8laSijd_ciqgH0SSsiyfG6F/s1600/Altitude_Plot.png" /> </a></div>
<div class="separator" style="clear: both; text-align: left;">
The blue line is the altitude which tops out around 250,000 feet. The green lines and the right hand scale show the weight of the vehicle in kg, which starts off at 98,000kg GLOW.</div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<br />Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-2496809921835393962013-03-21T05:25:00.000-07:002013-03-21T20:13:49.805-07:00PyDome Tutorial<div dir="ltr" style="text-align: left;" trbidi="on">
<h3 class="MsoNormal" style="color: black; text-align: left;">
Running PyDome</h3>
<ol style="text-align: left;">
<li> Install Python. The code was developed under Python 2.7. Packages for
all operating systems (Windows/Mac/Linux) are available from <a href="http://www.python.org/getit/" target="_blank">http://www.python.org/getit/</a> </li>
<li>Create a directory under your users home directory and copy all the PyDome files there. This will be where you run the script from and save the output to.</li>
<li>Update the 'config.py' script to set the dome diameter and the geodesic frequency.</li>
<li>Run the 'geo.py' script from the command line. The default output is to
print the results on the screen, so to save it to a text file just
redirect the output:<br /><br /><span style="font-family: "Courier New",Courier,monospace;">python geo.py > output.txt</span></li>
</ol>
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<br /></div>
</div>
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An
average desktop PC should take around 45 seconds to run for a 6V
sphere, with lower frequency calculations taking even less time.</div>
<div class="MsoNormal" style="color: black;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj36d2txNh_DGm4moXz698NWAjvfXs4Bg8EMLoaA42vdgxgpaD64kWe-LXflit_kujqXUFTf5zK2UgGA36szz3cg3Wj2QJmNeitA-G-AD6bQtQLqjB18rcvCmo77kMOjaR4Dd9B5WmiE3rM/s1600/2V_6m_Dome.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj36d2txNh_DGm4moXz698NWAjvfXs4Bg8EMLoaA42vdgxgpaD64kWe-LXflit_kujqXUFTf5zK2UgGA36szz3cg3Wj2QJmNeitA-G-AD6bQtQLqjB18rcvCmo77kMOjaR4Dd9B5WmiE3rM/s1600/2V_6m_Dome.png" height="197" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">2V Dome results in CAD</td></tr>
</tbody></table>
<br /></div>
<h4 class="MsoNormal" style="color: black; text-align: left;">
Output</h4>
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<br /></div>
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The output consists of the list of points with Cartesian coordinates:</div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"><br /></span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">/*****************************</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">*****************************/</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">* Points </span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;"> *</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">/*****************************</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">*****************************/</span></div>
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<span style="font-family: "Courier New",Courier,monospace;">Pt77 = (-3782.10808464, 129.73646238, 4656.05271517)</span></div>
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<span style="font-family: "Courier New",Courier,monospace;">Pt246 = (5547.56463791, 1201.67534466, 1944.35155109)</span></div>
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<span style="font-family: "Courier New",Courier,monospace;">Pt112 = (4854.10196625, 3526.71151375, 0)</span></div>
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<span style="font-family: "Courier New",Courier,monospace;">Pt402 = (1854.10196625, 4253.25404176, -3804.22606518)</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Pt165 = (-571.430583503, -5647.38560167, -1944.35155109)</span></div>
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<br /></div>
<div class="MsoNormal" style="color: black;">
<br />
As well as the list of edges showing both endpoints and their coordinates:</div>
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<br /></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">/*****************************</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">*****************************/</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">* Edges </span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;"> *</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">/*****************************</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">*****************************/</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"><br /></span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Point Pt77 Edge List:</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">------------------------------</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">----</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Edge187: Pt74 = [ -3000.0, 974.759088699, 5103.90485011] - Pt77 = [ -3782.10808464, 129.73646238, 4656.05271517]</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Edge188: Pt77 = [ -3782.10808464, 129.73646238, 4656.05271517] - Pt76 = [ -3917.72834195, 1272.94710279, 4362.45462008]</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Edge200: Pt77 = [ -3782.10808464, 129.73646238, 4656.05271517] - Pt75 = [ -2736.75911987, -209.918005711, 5335.36165135]</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Edge202: Pt83 = [ -3464.10161514, -1125.55484451, 4767.92683375] - Pt77 = [ -3782.10808464, 129.73646238, 4656.05271517]</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Edge203: Pt79 = [ -4618.03398875, 449.02797658, 3804.22606518] - Pt77 = [ -3782.10808464, 129.73646238, 4656.05271517]</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Edge204: Pt77 = [ -3782.10808464, 129.73646238, 4656.05271517] - Pt84 = [ -4428.16927497, -759.490479512, 3976.74377899]</span></div>
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<br /></div>
<h3 class="MsoNormal" style="color: black; text-align: left;">
Generated code for CAD Programs</h3>
<div class="MsoNormal" style="color: black;">
It
is easy to modify the code to generate output in a format which can be
easily used in a CAD program. I have used CATIA for my examples, as it
can run Visual Basic macros to do tasks. I simply created a macro which
recorded the creation of two points and a line between them for an edge.
Then I added the function ‘Get_CATIA_Desc’ to the Coordinates and Edges
classes to print out the data with the right text. To generate all the
points and edges in a CATIA part I just copy and paste this output into
the VB editor and run the script.</div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
Sample VB code to create a point in CATIA:</div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">Set hybridShapePointCoord369 = hybridShapeFactory1.</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">AddNewPointCoord(1958.</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">86417097, -636.473551394, -5635.40172286)</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">body1.InsertHybridShape hybridShapePointCoord369</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">part1.InWorkObject = hybridShapePointCoord369</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">part1.Update</span></div>
<div class="im" style="color: black;">
<div class="MsoNormal">
<br /></div>
<h3 class="MsoNormal" style="text-align: left;">
Program Structure</h3>
The
advantage of using a language like Python is the Object Oriented (OO)
nature of the language, which enables the code to reflect the structure.
The objects which are modelled are the geodesic sphere (GeoSphere.py),
icosahedron faces (IcoFace.py), edges, (Edge.py), and coordinates/points
(Coordinates.py). The main GeoSphere class keeps track of a list of all
the points and edges.<br />
<div class="MsoNormal">
<br />
<h3>
Algorithm </h3>
Each
face of the icosahedron has known coordinates, as determined from the
equations in <a href="http://www.vb-helper.com/tutorial_platonic_solids.html" target="_blank">Platonic Solids Tutorial</a>. Given these
coordinates we can process each of the 20 faces at a time and use vector
maths to calculate the delta vectors from a starting point A to the
other two corners B and C. The location of each of the
intermediate points can then be determined by scaling the delta vectors
according to the frequency, and then iterating to get each row and
column. </div>
</div>
<div class="MsoNormal" style="color: black;">
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSapzMfFVRHT4wLBDfCOQyOSIOopXTnluqIVzR0JeoY7PTMvmikQU-ROITGhzk11HPYtfjoqJNONdXmbjZmiQJjC4mju9LeuuvJjB5vAsmTaliKZ9BLwjm1Ap5ep_gL6FEkGIBMlW6rdwQ/s1600/Icosahedron_face_dividedV4.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSapzMfFVRHT4wLBDfCOQyOSIOopXTnluqIVzR0JeoY7PTMvmikQU-ROITGhzk11HPYtfjoqJNONdXmbjZmiQJjC4mju9LeuuvJjB5vAsmTaliKZ9BLwjm1Ap5ep_gL6FEkGIBMlW6rdwQ/s1600/Icosahedron_face_dividedV4.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Icosahedron with one face divided for a 4V geodesic sphere</td></tr>
</tbody></table>
<br />
For example a frequency 4 dome would have each face divided into
4 rows and 4 columns. </div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfQoeUbgFoBL8iQ3XkyuRnSCoYSX4llMa8C0p-nkACgs_u1sXUWdIzfSRGYXVibe-USlrB0KO2r5RgoJmvrs2eL0H9Y387UUSthbfX9zSscyjYkPr5r9Py6V7l-bfXqc6mJEYTITBKmDHX/s1600/Ico+Face+Layout.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfQoeUbgFoBL8iQ3XkyuRnSCoYSX4llMa8C0p-nkACgs_u1sXUWdIzfSRGYXVibe-USlrB0KO2r5RgoJmvrs2eL0H9Y387UUSthbfX9zSscyjYkPr5r9Py6V7l-bfXqc6mJEYTITBKmDHX/s1600/Ico+Face+Layout.png" height="320" width="312" /></a></div>
<br />
The scaled delta vectors would then be calculated as: </div>
<div class="MsoNormal" style="color: black;">
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwMtexqvmGe8mqR1iGZBl27Nt06jRjyyKtD8zEXvmUwdXNKAMLqHgXmpGQLRgKwVX7dnaL9164vwqnZMfkH2-DzAtz2xajFootnKv1LgbR_RxFsNJBLJHT82U1Q9EyBMG5kSIfKHsc0-Y7/s1600/Delta_Vec.tiff" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwMtexqvmGe8mqR1iGZBl27Nt06jRjyyKtD8zEXvmUwdXNKAMLqHgXmpGQLRgKwVX7dnaL9164vwqnZMfkH2-DzAtz2xajFootnKv1LgbR_RxFsNJBLJHT82U1Q9EyBMG5kSIfKHsc0-Y7/s1600/Delta_Vec.tiff" /></a></div>
where f is the geodesic frequency.<br />
<br />
With
one counter for the row number and one for the column number, we can
start at point A and use a loop over these counters to determine each
point. </div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"><br /></span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">for i in range(0,self.freq_n+1): -- Row number</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"> for j in range( 1, self.freq_n - i + 1): -- Column number</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"> </span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;"> </span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;"> </span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"> # Calculate the new coordinates based on the offset from the initial point (A)</span></div>
<div class="MsoNormal" style="color: black;">
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifpMJIffGta8En0EF6y5WVZr5EAwM5Nu9PUtBdM_1F30qO4z440YrjGp_JSdDM3cOr1FdwcnXpVtlFyC0Y2963vznhwWapNMkQB0be8eAGCJmFSAhilRlSb37ftw5qcqtAL88JZh4Cm-El/s1600/X_Vectors.tiff" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifpMJIffGta8En0EF6y5WVZr5EAwM5Nu9PUtBdM_1F30qO4z440YrjGp_JSdDM3cOr1FdwcnXpVtlFyC0Y2963vznhwWapNMkQB0be8eAGCJmFSAhilRlSb37ftw5qcqtAL88JZh4Cm-El/s1600/X_Vectors.tiff" /></a></div>
</div>
<div class="MsoNormal" style="color: black;">
<wbr></wbr> <wbr></wbr> </div>
<div class="MsoNormal" style="color: black;">
As
each face is added to the GeoDome class the coordinates from each face
are added to the global list. Once all faces have been added then the
list can be checked for duplicate points, as any points on the line
where two faces meet will be doubled up.</div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
The
final step is to project each point onto the sphere. So far all the
calculations have been in Cartesian coordinates (x,y,z), however the
Coordinates class also keeps the polar coordinates (theta, phi, r). Each
point will then have its polar coordinates radius (‘r’) set to the same
value while keeping the angles theta and phi the same. Setting the
radius will also recalculate the Cartesian coordinates for each point.</div>
<div class="MsoNormal" style="color: black;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_HckqoyMHj7kNQS5ggLRKbvy5Mct3en7asGojTt6CHW5nVD3HNQbbGhZTYt_RJRE_bf0mDQSxN5Yrgt0Q7mmZaB7cGMpCj47IOljHADeF66rlriRAYK9ubdVZhKOIlZjduuv0MiPPuxv9/s1600/Icosa_Dome_Side.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_HckqoyMHj7kNQS5ggLRKbvy5Mct3en7asGojTt6CHW5nVD3HNQbbGhZTYt_RJRE_bf0mDQSxN5Yrgt0Q7mmZaB7cGMpCj47IOljHADeF66rlriRAYK9ubdVZhKOIlZjduuv0MiPPuxv9/s1600/Icosa_Dome_Side.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Icosahedron with sphere for projecting points</td></tr>
</tbody></table>
<br /></div>
<h3 class="MsoNormal" style="color: black; text-align: left;">
Advanced Modifications</h3>
<h3 class="MsoNormal" style="color: black; text-align: left;">
</h3>
<div class="MsoNormal" style="color: black;">
The user parameters are defined in a small section at the beginning of the 'geo.py' script. Currently there are three parameters, the frequency of the geodesic (frequency_n), the radius of the dome (R_mm), and a flag for sphere or dome calculations. The coordinates should be entered in mm as this gives better readability in the final results.<br />
<br />
To
calculate the coordinates of a 6 metre (6000mm) radius dome of frequency 6,
set these variables to the corresponding values as shown:</div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"><br /></span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">R_mm = 6000</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;">frequency_n = 6</span><br />
<span style="font-family: "Courier New",Courier,monospace;">Dome_calc = True </span></div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
There
are potentially lots of different methods of dividing the faces of the
icosahedron. Traditional geodesic domes or spheres divide each flat face
into equal lengths. When the points are projected onto</div>
<div class="MsoNormal" style="color: black;">
the
sphere they then have different lengths. An alternative method is to
divide the arc between the edge vertices into equal angles. In order to
change the calculation method for each face,</div>
<div class="MsoNormal" style="color: black;">
modify
the file GeoSphere.py in the function Add_Face. This section of the
code takes the 3 corner vertices and then calculates all the points
within that face. Just replace the function 'Get_Edges_Equal_Distance'</div>
<div class="MsoNormal" style="color: black;">
with an equivalent function.</div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"> #-----------------------------</span><wbr></wbr><span style="font-family: "Courier New",Courier,monospace;">-----------------------</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"> # Use this function to divide faces by equal distance</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"> #</span></div>
<div class="MsoNormal" style="color: black;">
<span style="font-family: "Courier New",Courier,monospace;"> edge_list = F1.Get_Edges_Equal_Distance()</span></div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<div class="MsoNormal" style="color: black;">
<br /></div>
<h3 class="MsoNormal" style="color: black; text-align: left;">
To Do List</h3>
<h3 class="MsoNormal" style="color: black; text-align: left;">
</h3>
<div class="MsoNormal" style="color: black;">
For each hub point calculate the angle of at which each edge meets at the hub. This would be both the angle between the edges and the angles of the edge from a flat plane.</div>
</div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com2tag:blogger.com,1999:blog-2379573080676380548.post-4498083569765228022013-03-12T05:06:00.002-07:002013-03-18T04:42:50.064-07:00Geodesic Domes using Python<div dir="ltr" style="text-align: left;" trbidi="on">
<span style="background-color: #9fc5e8;"><span></span></span>Over the last few months I have been learning some of the maths
behind geodesic domes. I was specifically interested in being able to
generate the coordinates for all the points in a way which had enough
accuracy to be able to use in a CAD program.<br />
<br />
While I was investigating how the vertex points are generated I found this great site with all the information necessary to calculate the main points of the <a href="http://www.vb-helper.com/tutorial_platonic_solids.html">Icosahedron</a>.
From there the algorithm is fairly simple to explain, if a little
harder to implement! Each of the 20 triangular faces is divided into
smaller triangles according to the frequency of the dome. For example a
5V dome would have each face divided into 5 rows of equally sized
triangles. From there each point is projected outwards onto a sphere to
create the dome arrangement.<br />
<br />
To make this easier and
faster, I have written a small program in Python to do exactly this. At
the moment it takes in the radius of the geodesic sphere and the
frequency, and outputs the coordinates and edges. To make it easier I
also made the printed output of the coordinates and edges as a piece of
text which can be copied into the CATIA VB script tool, and then run as a
VB script to automatically create the points and lines.<br />
<br />
If you just want to print the cartesian coordinates then the printing of this CATIA code can be commented out.<br />
<br />
As an example, here is a picture in CATIA of a frequency 9 dome with a 10 metre diameter.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZumORp3tQm1If8xjWlZT16IgdtgH-2sRkRx6KQBM6noXX6rnsso8xzEvE94UjjeyQ3wc8baEYoe1GfarrzE31hRpm0yBkhcinbftkJ-8eusIPCWDCFU7mdseUXt6ypUysBk5UDnfycOvJ/s1600/9V_10m_Sphere_1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZumORp3tQm1If8xjWlZT16IgdtgH-2sRkRx6KQBM6noXX6rnsso8xzEvE94UjjeyQ3wc8baEYoe1GfarrzE31hRpm0yBkhcinbftkJ-8eusIPCWDCFU7mdseUXt6ypUysBk5UDnfycOvJ/s320/9V_10m_Sphere_1.png" height="178" width="320" /></a></div>
<br />
Here is another one of a smaller frequency 5 sphere with a 4 metre diameter.<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrigd9-S5EYKwlKyk2IaUppC3dxDoLDmFEAig0LuViH54alvhxEoPPbtyzKixn1WDhQkRg3XV6jegl02k2ldtk9ep2oQD8dDTVPfPZSvt8VO64QWEOqnbBvOQBnpsNKzhn5EuYvCgpMOmm/s1600/5V_4m_Sphere.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrigd9-S5EYKwlKyk2IaUppC3dxDoLDmFEAig0LuViH54alvhxEoPPbtyzKixn1WDhQkRg3XV6jegl02k2ldtk9ep2oQD8dDTVPfPZSvt8VO64QWEOqnbBvOQBnpsNKzhn5EuYvCgpMOmm/s320/5V_4m_Sphere.png" height="200" width="320" /></a></div>
<br />
In order to share the code I have created a project on Google Code in a Subversion repository. You can download the code from <a href="http://code.google.com/p/pydome/" target="_blank">PyDom</a> or checkout directly with Subversion using the command:<br />
<span style="background-color: white;"><br /></span>
<span style="background-color: white;"><tt id="checkoutcmd">svn checkout <b><i>http</i></b>://pydome.googlecode.com/svn/trunk/ pydome-read-only</tt></span><br />
<br />
Please let me know any suggestions for improvements!<br />
<br />
The
biggest enhancement to this script in the future will be the ability to
calculate the angles at which the edges meet at each point. This would
be crucial to enable the construction of the hubs to anchor all the
edges.<br />
<br />
Please let me know of any suggestions or fixes, keeping in mind that this is a work in progress!<br />
<br />
Thanks,<br />
<br />
Tim<br />
<br /></div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com5tag:blogger.com,1999:blog-2379573080676380548.post-30585231656372410932012-05-29T05:42:00.001-07:002012-05-29T05:42:24.220-07:00DH-1 Dimensions<div dir="ltr" style="text-align: left;" trbidi="on">
In preparation for making a CFD model in OpenFOAM, I have put together a drawing showing the main dimensions of the combined stage 1 and stage 2 vehicle. This gives me the data points to create a 2D model.<br />
<br />
<a href="https://docs.google.com/open?id=0B_xHz3R-zUNtMDdIVXA1aFRpWEE">DH-1 Dimensions</a></div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-14919677545608708952012-05-23T05:58:00.003-07:002012-05-23T05:58:50.950-07:00CADAC Variable Locations<div dir="ltr" style="text-align: left;" trbidi="on">
In the Fortran code for the CADAC4 software, variables are defined with a specific location. The number range is in the manual, however which variables are stored in which number location is not summarised. To help with this I wrote a Perl script to scan all the Fortran user modules and put together a list of all the names and locations. This helps me to know which spots are free for adding my own code, and means that if I do use a parameter it will have the same location.<br />
<br />
<a href="https://docs.google.com/spreadsheet/pub?key=0AvxHz3R-zUNtdFFRM0FrZzMtbXd1aURuZGN5ckJ2X3c&output=html">CADAC4 Variable Locations</a></div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-33800339218108943272012-05-23T05:54:00.000-07:002012-05-23T05:54:56.536-07:00Updated Rocket Engine Data<div dir="ltr" style="text-align: left;" trbidi="on">
I have been working on updating my summary of <a href="https://docs.google.com/spreadsheet/pub?key=0AvxHz3R-zUNtdDVwbks3anNZZ1pnVUFEZUZDMHdkQXc&output=html">Rocket Engine Data</a>. I have added in the Russian RD-192 engine, as it is about the right size for the main boost engine for the DH-1. I have been trying to find as much data on this as I can, because it runs on the Methane/LOX mixture which is of interest for the first stage.<br />
<br />
I am also working on trying to get the <a href="http://www.openfoam.org/">OpenFOAM</a> CFD software installed to try and get some basic numbers for the drag coefficients. At the moment the CADAC software is using the same coefficients from the basic sounding rocket example. Also the thrust calculation is a bit wrong because it assumes the exit pressure of the rocket will be the atmospheric pressure (Pe = Patm). However this is not the case especially for the sustainer RL-10A-4 engines.</div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-55517999494890066672012-04-26T05:48:00.001-07:002012-04-26T05:48:16.829-07:00Pictures of the DH-1<div dir="ltr" style="text-align: left;" trbidi="on">
Using the dimensions specified in the book, I have put together a quick CAD model of what the DH-1 would look like. This is useful to get a feel for the size of the structure, and by putting a manikin into the scene it also gives an idea of the actual space inside as well. I will be working on this over time to improve it, but for now this is what I anticipate a fully reusable, two stage space launch vehicle to look like!<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9_AZUJDo5iYG0FDW7Jd9DFRrGqV_mcmjR0upWa4j10HP_zmmCtjysOySGFqEb83dhq9EQgBd_WLCA10URhbznyWfpkNzzMtSBFIqwPIgiYALqd-zCeNWdjY5AsKciAMhiILHKBXSOrKsN/s1600/DH1_Front_Quarter.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="188" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9_AZUJDo5iYG0FDW7Jd9DFRrGqV_mcmjR0upWa4j10HP_zmmCtjysOySGFqEb83dhq9EQgBd_WLCA10URhbznyWfpkNzzMtSBFIqwPIgiYALqd-zCeNWdjY5AsKciAMhiILHKBXSOrKsN/s320/DH1_Front_Quarter.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">DH-1 Both stages. The porthole for 1st stage cabin is visible between the two jet engine pods</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIfRkCNhoN6pUK1yd4EbEo3P9RtSMYBu8FIq13lxF6i109BxOEnqvXq7VGasfUGK_-9yDPbaQ55xxDT3s-9Emj8vufn8sSfsgqDwhp_Ov22P7k3qsgIeBtk4N0GY26D7sBUXQMIyTLSPxA/s1600/DH1_Rear_Quarter.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="188" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIfRkCNhoN6pUK1yd4EbEo3P9RtSMYBu8FIq13lxF6i109BxOEnqvXq7VGasfUGK_-9yDPbaQ55xxDT3s-9Emj8vufn8sSfsgqDwhp_Ov22P7k3qsgIeBtk4N0GY26D7sBUXQMIyTLSPxA/s320/DH1_Rear_Quarter.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">View from the rear. The 3 large purple objects are the main boost engines.</td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-YFKbGNi1jbAFfkol8nh9K8eu33iKOHNcJh3KuprPPcMZ3jmoo_YAHfNjOyH-w23vVOu8tlSi1LtnLHbLT7qAvIuyVfPuiM07mQ8gN4O8bs7hn5HWrMTNFjekGjORsyRX06_wGpxDNd95/s1600/DH-1+S2+Cabin.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-YFKbGNi1jbAFfkol8nh9K8eu33iKOHNcJh3KuprPPcMZ3jmoo_YAHfNjOyH-w23vVOu8tlSi1LtnLHbLT7qAvIuyVfPuiM07mQ8gN4O8bs7hn5HWrMTNFjekGjORsyRX06_wGpxDNd95/s320/DH-1+S2+Cabin.JPG" width="221" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A closeup of the 2nd stage cabin area. The curved base of the heat shield, and the cutout for the boost motor are shown. The fuel tank for the second stage would be in this lower part of the structure.</td></tr>
</tbody></table>
<div class="separator" style="clear: both; text-align: center;">
</div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhARwfzLW9qPgNVTk0mKylsyS6S2tPH0A2y8ge75kHlKvi7_TexaFbiCeGxT0IyCvBVQctz8if4-ucaMHZ8Y56G2J-u11OsboxV5Qubr484BWnxUHJea0IH6CXbIOOLZpbTYaJu9R6rh9fx/s1600/DH-1+Side+Profile.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhARwfzLW9qPgNVTk0mKylsyS6S2tPH0A2y8ge75kHlKvi7_TexaFbiCeGxT0IyCvBVQctz8if4-ucaMHZ8Y56G2J-u11OsboxV5Qubr484BWnxUHJea0IH6CXbIOOLZpbTYaJu9R6rh9fx/s320/DH-1+Side+Profile.JPG" width="221" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Side profile of the first and second stages together. The manikin shows where the second stage cabin area would be between the two planes.</td></tr>
</tbody></table>
<br />
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcDlqEtJDO7Uts43gBHSzFvIHllTnQBTDwr2y-TZDTxi1-fKWSnvdHwMSVJCM7C-9GkYztbITWfNR2ClK_Ly4gDjJCe617uHgckpKF6KooNGnNDwktlkiJOERlHaOZ8-A7h8hSSBiey2in/s1600/DH1_Back.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcDlqEtJDO7Uts43gBHSzFvIHllTnQBTDwr2y-TZDTxi1-fKWSnvdHwMSVJCM7C-9GkYztbITWfNR2ClK_Ly4gDjJCe617uHgckpKF6KooNGnNDwktlkiJOERlHaOZ8-A7h8hSSBiey2in/s320/DH1_Back.png" width="203" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgliLsIqN3ciW0cyOIceDucCXCWRIuymGhMVTgNYK9BsyxdQ2R5oGsZh2tOJnxYVnEVyLyU5LW9tugnNGzxG_XUUn12v6v2MMfHzIe5_PjXM8AMOltbMYyZIB5gGEKu06UkOsHH2dEpY-Qq/s1600/DH1_Front.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgliLsIqN3ciW0cyOIceDucCXCWRIuymGhMVTgNYK9BsyxdQ2R5oGsZh2tOJnxYVnEVyLyU5LW9tugnNGzxG_XUUn12v6v2MMfHzIe5_PjXM8AMOltbMYyZIB5gGEKu06UkOsHH2dEpY-Qq/s320/DH1_Front.png" width="199" /></a></div>
<br />
<br />
<br /></div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-15503516635480930962012-04-26T05:19:00.000-07:002012-04-26T05:20:47.276-07:00CADAC4 - Head.ASC<div dir="ltr" style="text-align: left;" trbidi="on">
The two input files for the ROCKET.EXE executable are the HEAD.ASC and the CADIN.ASC. The HEAD file looks something like this:<br />
<br />
<blockquote class="tr_bq">
SCROLL NOECHOIN NOINTMSG NOSTGMSG NORANVAR NOTRAJBIN TRAJASC NOSTATBIN NOSTATASC NOTABOUT NOSWEEP<br />
*<br />
51 REARTH E Radius of the Earth = 6370987 - m<br />
52 CRAD E Conversion factor = 57.29577951 (Deg/Rad)<br />
54 AGRAV E Acceleration due to gravity @ sea level =<br />
58 WEII3 E Earth Angular rotation = 7.2921154E-5 (rad/s)<br />
200 MAIR D =0:Std Atmosphere, =1: Weather Deck<br />
201 TEMPK G Atmospheric temperature - degK<br />
202 PRESS O Atmospheric pressure - Pa<br />
203 RHO O Atmospheric density - kg/m^3<br />
204 VSOUND G Sonic speed - m/sec<br />
* 205 GRAV O Gravity acceleration - m/s^2<br />
206 VMACH O Mach number of rocket - ND<br />
207 PDYNMC G Dynamic Pressure - Pa<br />
1200 MAERO D =|MAERT|MAERV|, MAERT=1:Type, MAERV:Stage #<br />
* 1201 CD O Drag coefficient - ND<br />
* 1202 CL O Lift coefficient - ND<br />
1203 ALPHAX D Angle of attack - deg<br />
* 1206 CA G Axial force coefficient - ND</blockquote>
<br />
The original file is generated from the MKHEAD3.EXE program parsing the MODULE.FOR code and extracting all the parameters. However in order to get some output from the run, some of these parameters need to be marked as outputs. This is done by putting an asterisk ('*') in the second column. If there is no asterisk then this variable is not written to the TRAJ.ASC output file.</div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-47830816996982007252012-04-24T23:37:00.000-07:002012-04-25T00:29:37.251-07:00Finding Customers for Aerospace Startups<div dir="ltr" style="text-align: left;" trbidi="on">
<br />
The hardest part of developing reusable launch vehicles isn't the engineering work. It is because there are no customers for the vehicle when it is designed, built, and tested. This week I was watching the YouTube video <a href="http://www.youtube.com/watch?v=F1CGPdJQ_oo">Why Accountants Don't Run Startups: Steve Blank</a>. Although the lecture was about technology and Internet startups, the most interesting point was about finding the right business model through testing assumptions about customers and then rapidly pivoting in a new direction as new insights came through. By remaining flexible in the early stages of the search, the direction of the company and the product can be adjusted rapidly to find a profitable business model.<br />
<br />
This contrasts with the way in which people have searched for ways to enable low cost access to space. The focus has been completely on the engineering model and technical design. The lack of customers has been assumed to be a problem which will be solved once the brilliance of the chosen approach becomes obvious. However if we take a leaf out of the Steve Blank "Customer Development" model, then we should not start with the engineering but rather with the customers. We need to find what the customers want, and even who they are, before we spend the money doing the engineering.<br />
<br />
This is incredibly difficult because there are no customers out there. The customers for the new type of launch vehicle will be companies and business models which also dont exist yet. There is one new option though: <a href="http://www.planetaryresources.com/">Planetary Resources</a>. The announcement that this new company will be working towards mining asteroids means that there is at least one customer in the medium to long term who will be looking for lots of low cost launches. If they develop as planned then this will particularly be the case once they start looking at launching the robotics necessary to actually do the mining. This will be a significant amount of payload the be launched.<br />
<br />
So now the question is, can we build the DH-1 so that it meets the future requirements that Planetary Resources will have for their payloads? Since their plan is to use robotics and not manned missions, then on first reading it seems like the compromises made in the design of the DH-1 will be acceptable. This is to do with the size and shape and location of the payload bay.<br />
<br />
If we could get some funding to map out further how the DH-1 would work, and at the same time be building links with the Planetary Resources guys to feed the information back then it may be possible to use this new option as the main launch customer for the DH-1.</div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-15444623360742632082012-04-10T05:14:00.001-07:002012-05-23T05:55:48.271-07:00RL-10 Engine Data<div dir="ltr" style="text-align: left;" trbidi="on">
One of the proposed rocket engines used in the DH-1 is the RL-10. To help get some good figures, I have used a summary of data about this engine, along with a few further figures on mass flow rates and the characteristic velocity. These numbers will be used in the simulations to make sure that the thrust and mass flow rates used are correct.<br />
<br />
<a href="https://docs.google.com/spreadsheet/pub?key=0AvxHz3R-zUNtdDVwbks3anNZZ1pnVUFEZUZDMHdkQXc&output=html">Rocket Engine Data</a></div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-72226230799440406592012-04-10T04:38:00.003-07:002012-04-10T04:40:13.546-07:00DH-1 Flight Profile<div dir="ltr" style="text-align: left;" trbidi="on">
This document shows what the flight profile of the DH-1 will be for both the first and second stages. I am slowly filling in the numbers for height, speed, weight, etc as I complete the analysis using CADAC4. Updated versions of this will be posted as I get some good figures.<br />
<br />
<a href="https://docs.google.com/viewer?authuser=0&srcid=0B_xHz3R-zUNtZWJvZ2t2T1drMXM&pid=explorer&a=v&chrome=false&embedded=true%22%20width=%22640%22%20height=%22480%22%3E%3C">DH-1 Flight Profile</a></div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-20150168828953449962012-04-09T06:32:00.000-07:002016-04-10T17:58:06.633-07:00CADAC4 Software<div dir="ltr" style="text-align: left;" trbidi="on">
I have been learning to use the CADAC4 software, which is available for download from the AIAA or as part of the self study CD:<br />
<br />
<h3 class="detail-title">
Fundamentals of Six Degrees of Freedom Aerospace Simulation and Analysis in FORTRAN and C++</h3>
<div class="detail-series top2">
Library of Flight
</div>
2004, CD ROM<br />
<div class="isbn-13">
ISBN: 9781563476907</div>
<div class="isbn-13">
</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXOQsgCzMJW7FBwYiJkdmXNtbIIzffSVjT9qFojVQqLZoNqKiPjOPGMjVD9LixyyR-bkdNIKE1ynVuVfwFHTsbItk3ZoqoTtb-Jp82brmRVlCo47U8Q5bKeIZj6YBqK_5rdZwCPiX811jY/s1600/9781563476907-150.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXOQsgCzMJW7FBwYiJkdmXNtbIIzffSVjT9qFojVQqLZoNqKiPjOPGMjVD9LixyyR-bkdNIKE1ynVuVfwFHTsbItk3ZoqoTtb-Jp82brmRVlCo47U8Q5bKeIZj6YBqK_5rdZwCPiX811jY/s1600/9781563476907-150.jpg" /></a></div>
<div class="isbn-13">
</div>
<div class="isbn-13">
The Fortran version of the software is available from the AIAA. However I found there were a few issues when using the code under Windows and compiling with Gnu Fortran (gfortran). To fix this I had to edit some of the files especially to do with reading and opening files. I will upload the corrected versions of these files here.<br />
<br />
Reference link: http://arc.aiaa.org/doi/book/10.2514/4.102523<br />
</div>
<h3 class="detail-title">
</h3>
</div>
Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-41902153752113189492012-03-26T04:39:00.001-07:002012-03-26T04:39:24.319-07:00DH-1 Detail Data<div dir="ltr" style="text-align: left;" trbidi="on">
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DH-1 Detail Data </h2>
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I have put together some summaries of all the relevant figures for the DH-1 vehicle as per the data in the book. In the version I have the are some inconsistencies with the figures used so this puts it all together to make it clear.<br />
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<a href="https://docs.google.com/spreadsheet/pub?key=0AvxHz3R-zUNtdFVnZmNjenBtVDkyZTVjRDZiam5veUE&output=html">DH-1 Detail Data</a> </div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-41134645970507185322012-03-22T23:40:00.002-07:002012-03-22T23:40:41.516-07:00Why Does Space Inspire UsI have just been reading more about SpaceX and this clip from Elon Musk is very useful.
<a href="http://www.youtube.com/watch?v=_yDZY5_u8FQ&feature=youtube_gdata_player">Why Does Space Inspire Us - Elon Musk</a>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-5430106827992636682012-03-22T04:34:00.001-07:002012-04-09T06:24:52.285-07:00The Rocket Company Book<div dir="ltr" style="text-align: left;" trbidi="on">
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This book was the one which finally confirmed to me that it was actually possible to engineer a space launch vehicle which was low cost and fully reusable. Please read a copy of this book, as it contains all the details of the business plan and the DH-1 reusable launch vehicle. This is the baseline for my analysis, and I hope to fill in more of the engineering details as I go to confirm the viability of this design.</div>
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The details of the book are below:</div>
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<u><span id="btAsinTitle"><span style="font-weight: normal;">The Rocket Company (Library of Flight Series)</span></span></u></div>
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<span id="btAsinTitle"><span style="font-weight: normal;">Author: Patrick J.G Stiennon</span></span></div>
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<span id="btAsinTitle"><span style="font-weight: normal;"></span></span><span class="byLinePipe">ISBN-10:</span><span style="font-weight: bold;"> 1563476967 </span> <span class="byLinePipe"> | ISBN-13:</span><span style="font-weight: bold;"> 978-1563476969</span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAuIAusyOXW0oI5MJWn-31RgnQsRFcEg1d5ckSBo-gMNOvp9HwSrgiPkFwNl8CY01WuyIh2LQCxsnNGZ15AjveijLpjwahNTsi16uBMsWgbtWs2yOWvbzcH5k4em_gpFObwV5UuyStj_9j/s1600/Rocket_Company_Book_Cover.tiff" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAuIAusyOXW0oI5MJWn-31RgnQsRFcEg1d5ckSBo-gMNOvp9HwSrgiPkFwNl8CY01WuyIh2LQCxsnNGZ15AjveijLpjwahNTsi16uBMsWgbtWs2yOWvbzcH5k4em_gpFObwV5UuyStj_9j/s320/Rocket_Company_Book_Cover.tiff" width="211" /></a></div>
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</div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com0tag:blogger.com,1999:blog-2379573080676380548.post-62919662296818096912012-03-22T04:21:00.000-07:002012-03-22T04:21:12.278-07:00Introduction<div dir="ltr" style="text-align: left;" trbidi="on">This blog is the first step in achieving my goals.<br />
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There are three aims for this blog:<br />
<ol style="text-align: left;"><li>Contact other people with a vision to build low cost reusable rockets</li>
<li>Share information about low cost reusable rockets and the business methods behind them </li>
<li>Provide a platform for charting my progress</li>
</ol>I am a 32 year old Aerospace Engineer who works as a software developer. I believe that there is a revolution occurring in the space industry, as the transition from government development to private development occurs. This transition has many exciting opportunities that I want to be part of. <br />
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Therefore I have opened this blog as the first tangible step in this process. Please contact me if you wish to share ideas, thoughts, or information.<br />
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Thanks,<br />
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Tim</div>Mitohttp://www.blogger.com/profile/15544883125032112145noreply@blogger.com1Sydney NSW, Australia-33.873651 151.20688960000007-33.885485 151.19397910000006 -33.861817 151.21980010000007