I’ve started building the R13, an oddroc I conceived of almost a year ago. I’ve been referring to it here as RX, but forget that. I decided last year to build a smaller, less odd prototype, the Rxiiiab; I built it, flew it, painted it, declared victory, and this year I build the real thing.
This will be a finless, tail cone stabilized rocket. Like the Rxiiiab it’ll be rear ejection, with the laundry — a chute this time — packed inside the cone. If that’s not odd enough, it’ll… but no, just wait, you’ll see.
Yeah, I’m using ST tubing, not my usual Estes-type BT. There’s a reason. ST-115 is close to the right diameter. BT-50 is too skinny and BT-55 too fat. “Right” for what? Spoilers!
I expect this thing to be heavy enough to need a D motor, but I don’t think there’ll be enough room inside the cone to pack the chute around a 24 mm motor mount. So I’m going with 18 mm and expecting to fly it on Aerotech composite D motors.
Next I cut a piece of ST-115 about half an inch long and removed a slice to make something that’ll slide into the ST-115. Didn’t bother closing up the gap, not needed. And in fact the slice I took out was a bit too wide, so I don’t really want the gap fully closed. What I would have liked to do with that piece would have been to glue a ST-115 bulkhead to it, but as far as I can tell there’s no such thing on the market. And I didn’t feel like trying to cut one myself, so I took the lazy way out: I glued a -7 to -115 centering ring on, and then glued a BT-50 bulkhead on top of that.I glued Kevlar cord to one side and coated the other with epoxy. Which is taking its own sweet time hardening in the cold basement. So I’m calling it a night.