10-03-2011, 08:45 PM
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Flying since 1977
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Join Date: Oct 2010
Location: Middle TN
Posts: 452
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Quote:
Originally Posted by bernomatic
I looked at it, but could not find the factor which made the difference. My design is a minimum diameter, which to me would suggest that without the weight of the engine mount et al., I should have a better stability margin.
I am not unfamiliar with some of RockSim's quirks, http://www.apogeerockets.com/educat...wsletter253.pdf , and I think it is a great aid to designing and building model rockets. As I mentioned previously though, some think that if it's not stable in RockSim, it won't work and you shouldn't fly it. In other words, flight tests be ****ed, let's see the calcs!
While I don't adhere to this philosophy and was designing rockets long before there was a computer program to "do the calcs.", there are some in today's (younger) society who follow technology blindly and don't understand the age old concepts of trial and error and professional judgement.
Anyway, enough of my rambling, I was just wondering if there was anyone who may have come across this problem before and could offer a fix or go around.
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If I had the space, I would construct an analog computer, a wind tunnel, for these types of designs. The old V-2 will not work very well with the Barrowman equations (both simplified (i.e. Centuri's TIR -33) and the calculus-based original equations of 1966. I know the aerospace industry still uses wind tunnels to test models of new aerospace vehicles.
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'Til next time,
Mike Toelle
NAR 31692 L1
SAM 0373
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