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Old 10-10-2013, 10:11 PM
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Rich Holmes Rich Holmes is offline
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Default Estes Tornado stability?

I'm making a Tornado by kitbashing a Hi-Flyer , intending to launch it Saturday. I downloaded a RockSim file for the Tornado and I see it puts the CG right about where I find it to be on mine. (Huzzah!) But with the recommended motors (B4-2, B6-2, C5-3, C6-3) the stability ranges from 0.728 to 0.931 cal. So, well, yes, with the B motors it's almost 1 cal, and I have doubts about whether I'd ever want to put a C into this thing. Still, those numbers seem kind of low to me.

Has anyone out there had the same concerns, and tried to increase stability with some nose weight? 3 grams is enough to take it to the 1.3 to 1.6 cal range. But the nose section is only about 9 grams in the first place. I worry about whether adding 33% more weight, all in the nose, will ruin the maple seed recovery.

At this moment my inclination is to leave it alone, but I'd like to hear if anyone else has looked into this.
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Last edited by Rich Holmes : 06-10-2014 at 07:35 PM.
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Old 10-10-2013, 11:26 PM
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BEC BEC is offline
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That's an interesting little model - I've never heard of that one before.

I'd try calm days and vertical boosts (from a nice clean launch rod) before adding weight. Finding both pieces after a B-motivated flight might well be enough challenge that you won't need to try a C6-3.

C5-3s, of course, are long out of production and certainly not needed for such a small light rocket. Despite the implied lower thrust they actually are punchier - the perfect Fat Boy motor. But this little Tornado is no Fat Boy.
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  #3  
Old 10-11-2013, 05:10 PM
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The Estes Tornado/Twister (not the Classic Series kit) will fly just fine on ½A6-2s and A8-5s. You really don't want to use any larger motors if you want to get it back. With short rockets (less than 10:1 length to diameter), you can go below one caliber and it will still be stable. Conversely, with really long rockets (20:1 or more), you may need more than a one caliber margin. Remember, CP will shift forward with increasing angle of attack.
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Old 10-11-2013, 05:52 PM
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Rich Holmes Rich Holmes is offline
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Hmm, wonder why Estes didn't recommend any A motors. I see on rocketreviews.com most of the flights listed are on 1/2A or A. A couple successes on Bs (and one lost in the woods), and one on a C that disappeared. I'll probably start with an A.

I knew about getting away with fewer calibers for short rockets but didn't know it extended to 10:1. Will keep that in mind. Thanks!
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Old 10-12-2013, 01:10 PM
PaulK PaulK is offline
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I've always used 1/2A6-2, or A8-x on the Tornado. It would be tough to see the maple seed recovery on a B !
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Old 10-12-2013, 02:18 PM
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Posting from the launch... Put it up on an A8-3, good flight , had trouble finding the bottom in the grass. Not going to try a B today...
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