Weather continues to be wet and gloomy, but incremental progress is being made. The Estes Mercury Redstone is complete, the Centuri Sky Devil clone has a base coat of white, and I'm still sanding/finishing the 3D printed nose and fins for the Redstone missile and the plastic Jupiter. Sunday's humidity may be low enough to finish painting the Sky Devil and put a coat of primer on the Redstone. One can only hope...
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| The first page of the Zeta plans (Click to enlarge). |
With the Mercury Redstone finished, time for another project. I'm still waiting on some parts for the Gemini Titan, so I decided to look through the old Estes Design of the Month plans for a quick build. I kinda have a love/hate relationship with the Design of the Month - some of them, like the Space Twins, I really love, and there are others - like the Blue Lightning - that I can't stand. Anyway, I was poking around these
designs posted on JimZ's site, and ran across
#58, from 1968. It's called the Zeta and has a nice retro look - I particularly liked the ring joining the fins. A quick check of the parts inventory showed that I had everything in my bins, so I gathered the components and set to work.
The Zeta is a fairly straight forward build - with the exception of the ring that fits into the fin slots. You have to be pretty exacting in cutting out the fins for this BT-70 sized ring to fit properly, so I resorted to making them using the Cricut Maker. Even with this, the ring was a bit too small, so I had to slice it and add about a 1/4" wide strip for it to slide into the slots. 1/4" sounds like a lot, but this translates to about a 0.04" (1/25") error in the slot distance from the body tube. Not much at all, and a slight import error in the sizing could easily account for it.
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| Zeta fin ring showing the added 1/4" strip (Click to enlarge) |
The design calls for using a BT-55Z balsa tail cone to act as a transition from the lower BT-55 body to the BT-20 payload section. It's a nice concept, except that the BT-55Z does not smoothly merge into the BT-20 - after all it is a tail cone, and you have to leave some thickness of balsa around the end to support the motor tube and avoid chipping. Works fine on the tail end of a rocket, but that flat space around the BT-20 offended every aerodynamic sense in my aged body. So I made a small cardstock shroud to make things more aerodynamic and aesthetically pleasing. This means the build is not pure Zeta, as it deviates from the design; I guess I will have to call it the Zeta-A.
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Zeta forward section showing the flat space at the end
of the BT-55 9Click to enlarge). | Same thing, with the cardstock shroud added (Click
to enlarge). |
Everything is assembled and ready for finishing - here's the nekkid rocket shot. The ring is not yet glued in place, as I will finish it separately. My biggest issue now is deciding on a paint scheme - the plans show a checkerboard pattern and some horizontal stripes, but there is no way of deducing the colors. This model is not a common build (i.e., no pics to be found on the Internet), so I'm going to have to rely on my own color sense to come up with a decor. Hopefully it won't be ghastly.
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| The Zeta ready for finishing (Click to enlarge). |
