10-05-2019, 10:31 PM
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Craftsman
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Join Date: Aug 2007
Location: Whitehouse, Ohio
Posts: 264
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Quote:
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Originally Posted by JumpJet
If built per the kit and flown with two E12 motors the Shasha has a stability margin around 1.5 if memory serves me, so I'm not sure where you are getting your stability numbers from. The single stage model has a similar stability margin.
John Boren
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John,
You are correct! What is being discussed is the situation where the forward fin set is aligned (directly in line or on the same plane) with the aft fin set and not rotated 45 degrees with respect to each other as per the Estes instructions. There is new wind tunnel data to suggest that if the fins are aligned above one another the turbulence from the upper set of fins will negate some of the stability imparted by the lower set of fins. A kit built as per the instructions will not have the upper and lower fin sets aligned, they will be rotated along the airframe 45 degrees from each other.
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Bruce S. Levison, NAR #69055
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