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Old 01-18-2009, 01:40 AM
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Tau Zero Tau Zero is offline
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Join Date: Mar 2005
Location: Twin Falls, Idaho, USA
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Thumbs up Centuri Groove Tube -- RockSim 7

Quote:
Originally Posted by Mark II
Hey, Jay! What do you say?

OK, here's my first dilemma. I whipped up a RockSim 8 clone of the Centuri Groove Tube #KA-11. Everything is done per the plans found at JimZ's site, and it is built with parts from Semroc. The result matches up pretty well with the rocket's vital statistics shown in the 1972 Centuri catalog at Ninfinger.

The recommended engines are A8-3, B4-4 and C6-5. [SNIP]

The rocket is unstable using all recommended engines.

What am I missing?
Here's how the aforementioned Bruce S. Levison did it in RockSim 7 (see attached file originally downloaded from The Rocketry Forum [TRF]). He did it to contrast how inaccurate RockSim 8 was with its tube fin calculations.

Of course, now that I look at it, I realize *I* may have been misinterpreting the way Bruce models tube fins. On the other hand, I think I have *ring* fins down okay, since Bruce was kind enough to look over an early version of my Tau Zero design and tweak it so it actually worked.


Cheers,
Attached Thumbnails
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Name:  Centuri_Groove_Tube_RS7_BL_01.jpg
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Name:  Centuri_Groove_Tube_RS7_BL_02.jpg
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Size:  139.9 KB  
Attached Files
File Type: rkt Centuri_Groove_Tube_RS7_Bruce_Levison.rkt (76.7 KB, 138 views)
File Type: rkt Centuri_Groove_Tube_RS8_Bruce_Levison.rkt (47.1 KB, 127 views)
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Jay Goemmer
"Centuri Guy"/"Tau Zero"
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Semroc SAM #0029
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03 Sept 2014
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