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Old 06-14-2018, 10:42 PM
DavidQ DavidQ is offline
Craftsman
 
Join Date: Aug 2011
Location: Washougal Washington
Posts: 375
Default Bug-a-Bye

The Bug-a-Bye is a BT40 rocket with a clear payload section. Even though it is listed in their catalog, as of early 1960's, I didn't count on ordering the clear plastic tube. Instead, I went through my collection of old toy parts and stuff, and found that I had a section of clear tube with an OD of 0.83". Well, a BT40 tube is 0.825", so that's good enough to call it a match.

The body tube is some I rolled by hand. I had some heavy-weight kraft paper left behind from some painting I did, since it was a roll to cover the floor. I noticed the ID of BT40 is 0.765", and lo and behold, the OD of BT30 is also 0.765". Which made a BT30 into an instant mandrel for DIY BT40. I rolled a few, and used them on most of the BT40's coming up.

The fin canister on the Bug-a-Bye is supposed to be the SpinFin canister that Estes sold back in the early 60's. Which, again, I didn't have. So I made one. I wrapped more kraft paper around the BT-40 tube, gluing it in a wrap with a thickness of 0.03", or so. I trimmed it to length, glued the fins on with a spin angle, put a centering ring at the bottom as a shoulder, and now it is a removable fin canister.

Although I really like to build with fin alignment guides, I went back to an old school fin alignment guide. It comes on a roll, which back then was probably brown, and is now blue. Trusting that my eyes are good enough, I just held the fins in place with tape while they dried.

The canister comes off so the engine can go into the tube, against the engine block 2 3/4" up into the tube. I figure I'll have to use some tape to hold the fins on during launch.

Sand, prime, and paint. And decals. Voila!
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