Repairing the (scratch) B3S2 (part 1)

So, what was supposed to be the first of lots of flights for the B3S2 Saturday ended up being its last — in that form. As mentioned, the motor cato damaged the motor pod, the bulkhead, and the nose weight container. I decided to work on the latter first.

I’d just bought two Baby Bertha kits, so I could’ve rebuilt the nose the same way, but I wasn’t entirely happy with even the pre-cato nose. The weight container’s capacity wasn’t quite what I’d expected it to be, and it was hard to get the BBs in without spillage. Post-cato, well, I had worries about the viability of the container cap. I’m not even sure it wasn’t the ignition of the motor, rather than the cato, that overstressed the threads and broke them. Probably not, but I was nervous about it. Also the centering ring turned out not to be as securely glued as it should have been.

After some thinking it occurred to me a lot of the difficulty with that design had to do with the fact the nose cone was, well, a cone — okay, an elllipsoid. But why should I care about drag? I’m trying to downgrade the performance of this thing as it is. A cylindrical, flat-faced nose should be just fine.

So I took a neck cut off a soda bottle, and after sanding the cut edge I found it was an excellent match to a yellow Estes 24 mm engine spacer tube. I epoxied it on:

Then I glued a piece of BT-50 over that, and put a bead of epoxy across the joint.IMG_8814A bulkhead went in the other end.5060 centering rings: I cut some strips of 1/8″ basswood and glued them between the rings for added strength. Then I glued the whole assembly into a piece of BT-60. A yellow piece. Leftover from a Patriot kit.

In the other end a coupler.2016-05-24 19.38.16

And that’s the nose.

As for the bulkhead, I thought about just gluing another one over it; problem is, I’d lined the body tube with stiffening tubes, with the bulkhead sandwiched between two of them, and I’d have to make or modify a bulkhead to fit inside the stiffeners. Instead I decided to just stop up the small hole with some glue and leave it at that. It’s ugly but it’s way down inside and I promise not to look at it if you don’t.

 

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