Build thread: Blackfish

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neil_w

Hunkered down and slowly going crazy
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Final weight without shock cord and parachute comes out at 3.45 oz, a bit above model at 3.05 oz. Not too bad. CG, however, comes out somewhat further back at 19.5" vs. 17". I'm going to have to start including more fudge factor in my OR models, because there's clearly a lot more weight in the rear than I have planned. I'll need to recheck with shock cord and parachute, but it looks like I might need about 1/2 oz or hanging from the nose to stabilize this.

What I should really do is refrain from installing the eyelet in the nose cone until I do this measurement; easy to add weight *before* the eyelet, harder afterwards. I'll figure something out.

A JLCR would *almost* be enough, but probably not quite, and I can't assume I'll always use it. But in theory it should fit.
 

jqavins

Joseph Avins
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Once the shock cord and parachute are in, try adding a mass object to the model that's the right mass, then shift it around to find where it goes to get the accurate CG. That should give a clue as to where the extra weight is in the build. Just a clue, but maybe worth it.

My guess: it's all those decals. ;)
 

BABAR

Builds Rockets for NASA
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Wow, there’s a REAL blackfish!

 
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