I got to launch my Daedalus yesterday but did an odd corkscrew I haven't seen before.

I have a diagram of what it did, if it makes any sense. The nose always stayed pointed toward an imaginary apogee but the body (aft end) twirled around. I can only guess it was a borderline stability problem. Or maybe the large twin fins acted like ailerons. The bottom of the rocket was always pointed inward like it was gravitationally locked, like the Moon.

Attached Files

Daedalus_Flight_Path.pdf (453.9 KB, 50 views)

That's called "coning" or "pitch-roll coupling." It generally happens with long, thin rockets that are "over-stable." But, in your case, I think the cause is more complicated.

A more-thorough description of the phenomenon is at: http://www.info-central.org/?article=124

-- Roger

Because of the big nacelle/fins I had to put a bunch of weight in the nose. It seems that caused as much trouble as if solved...
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