Trying to stabilize the Dr Zooch Saturn V

I claimed I would not fly the Saturn V again after its unstable flight in May, but maybe I will, with some modification.

I built it pretty much according to the instructions, the biggest change (and potentially quite significant, I guess) being substitution of epoxy putty for funky glue putty in the engines. And perhaps I used more glue than some in my build? Whatever the reason, it didn’t fly straight.

I flew it on a C6-3. Would a B6 have been better? It would’ve shifted the center of gravity less far to the rear, though not by more than 5 mm or so by my measurement.

How about adding nose weight? The kit comes with a pre-weighted nose, but adding some more might work. I thought at first there was no good way to add weight to the built model. In fact I still think so. But how about a not so good way?

I drilled a hole into the third stage body tube. Squirted about a gram of epoxy in. Dropped in about 10 grams worth of lead BBs. Squirted in another gram of epoxy.

That leaves a hole in the body tube, of course. For now I can just cover it with a piece of white label paper. If it works maybe I can come up with something nicer looking.

If I use a B6 motor, and if I use a Mylar chute with no swivel in place of the thin mil nylon chute with swivel, then it should end up a few grams under the 113 g maximum recommended weight for the B6. The center of gravity I think will be 20 to 30 mm forward of where it was for the May flight. I’ll check those figures once the epoxy cures.

If weather permits and I decide I have the nerve, I’ll try flying it early on July 20, hopefully before any possible press shows up, and if it goes okay and possible press shows up I’ll fly it again. I probably should get the decals on before then.

Edit 16 July 2019 to add: Here it is with decals and dull coat:

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