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Board » General Discussion » IMSYC 2011

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Posted by
Rod


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2011-06-16 01:11:46 - Re: IMSYC 2011
,My own confusion came from the use of two different measurement systems used in the same table without any indication of what units were actually used. If the quantities had been labelled properly, some 400 people would, perhaps, have noticed, before the end of the race, that there were some inconsistencies in the "uprising" information. WhyNot noticed it first, AFTER finishing.
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
WhyNot


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2011-02-03 18:39:54
2011-06-16 06:29:05 - Re: IMSYC 2011
I'm WhyNot Rod. For some reason, my name comes up and not "WhyNot":)
Posted by
Rod


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2011-06-16 14:30:35 - Re: IMSYC 2011
Ah! It was good that you noticed. I certainly didn't, until you stated that there was a problem.
It just illustrates how we all accept printed material as correct, and rarely check on these obvious things.
I hope that this doesn't impact too seriously on the student-designer, but I think this problem should be pointed out. As an ex-educator, I know how important these things are in education.
Are you also Arrabiata? I liked your Desk-Top.

--- Last Edited by Rod at 2011-06-16 14:33:20 ---
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
WhyNot


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2011-06-16 14:48:39 - Re: IMSYC 2011
Nope, Arrabbiata is my Sunwind RC. That name was already taken when I joined SOL
Posted by
76Trombones


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2009-08-03 18:04:56
2011-06-16 14:57:51 - Re: IMSYC 2011
You can (if you want) change your forum display name under "edit profile" over in the login box to the left.

There aren't any inconsistencies with the polars - the text data is the same format for all the boats and the images show the same thing. Uprising was always going to be a fast boat - the designer identified where gains could be made and took advantage of that. Even if you change the 4m/s curve she's still wins, although by a smaller margin. That's immaterial though; everyone knew up front that what you see is what we get.

The glitch(es) in the polar(s) were introduced when the instructors ran the data provided by the student teams. You pay your money and you take your chances. The "design" of uprising is/was perfectly valid.

The single-number handicaps I presented at the start of the race took into account *all* aspects of the IMSYC polars in the expected wind at that time. Like any system, the accuracy of the handicapping varies with weather. A system arrived early and gave a downwind boost to a few boats. Such is life. If someone has archived the race weather I'll be happy to run the numbers with our true wind. Unfortunately I wasn't around for most of this race.

76T
Posted by
Rod


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2011-06-16 16:54:08 - Re: IMSYC 2011
Do you know what program was used to develop the design into the set of polars? My interest is in trying to do the same things for my design of Footy RC boats. I used Prolines 7 to design the hull. but I don't know how to determine the polars & performance.
At a one foot length, I can design, build, and sail my own racing yacht---I somehow doubt if they would yet give me the opportunity to do the same for the America's Cup----!!
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
76Trombones


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2011-06-16 17:14:50 - Re: IMSYC 2011
Jakob has posted the lecture notes, homework assignments and necessary code for the "Sailing for Performance" course.

The main focus of the course was learning the physics of sailing and developing the VPP rather than the final design. Enough info is presented to duplicate the students' efforts and write your own VPP (in Matlab, but open-source Octave/Freemat should work, or any other language with some changes to the framework). The basic code is extensible - for small boats you'd want to (at least) change the aero/hydro data to reflect scale effects.

Sailing for Performance

There is also a VPP online at polardesigner.org with some familiar names attached ;-). Scale will limit it's use for models, but it's fun to play with, and no code required.

There are some free spreadsheet-based VPPs out there too: "pcsail" comes to mind.

---------------
edited to shorten URL to fit in column

--- Last Edited by RainbowChaser at 2011-06-16 21:45:23 ---
Posted by
Rod


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2011-06-16 17:25:04 - Re: IMSYC 2011
Thanks. I will try----but may get swamped!!!
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
A2


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2009-10-26 00:39:42
2011-06-16 18:08:55 - Re: IMSYC 2011
Now that IMSYC 2011 has concluded can we revive your (76T's) 8 Metre Rule challenge using the aforementioned polardesigner.org ?

I have improved my boat & will race against all comers even if that means it is just 76T in a match race.

Once the "Cup" has been Won it will have more value for future competitions.

8^)

None so blind
Posted by
Arthur


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2008-12-23 14:43:47
2011-06-16 21:27:53 - Re: IMSYC 2011
Still waiting for a polar designer for more than 1 hull ;)
If you're still in control, you're not going fast enough.

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