Building the Squirrel Works Callisto (part 3)

The next item may be a bit of a surprise. I glued together the provided 18mm single motor mount.. Actually I omitted the thrust ring, and I only tacked the centering rings on with a couple spots of CA. What for? For this, to start with:2015-02-26 22.25.28

Having the single motor mount in place (dry fit) meant I could use the Estes fin positioning device. You’ll notice I used doubled lines for the fin markings again. Worth it.

After that I could do this:

Fillets and launch lug on the rotisserie.

I was surprised at the fit of the transition into the BT-55 tube, or rather, the lack thereof: it required a fair amount of sanding just to get it to the point where I could push it in, more still to make a good secure but ejectable fit. The BT-20 end and the nose cone shoulder, on the other hand, were just fine. I glued the transition into the tube, which, afterward, I began to think might’ve been better saved for later — well, no matter.IMG_3589

Finally, with the single motor mount still in place, I loaded up a parachute, stuck the nose weight and eye screw between it and the transition, and put a C6 in the motor tube for a rough center of gravity check. It came to about 3 7/8″ from the rear of the airframe, a quarter inch or so behind where my sim puts it. Then I pulled out the single motor mount and stuck in the 3×13 mount, with three A10s in place. Just for completeness, I slipped a #4 nut and washer on, to stand in for the #2 hardware I’ll get later.IMG_3591 IMG_3592

The CG moved back just slightly, maybe an eighth of an inch. Of course I’ll check again after I finish assembly and painting. My guess is I’ll want to add just a little more nose weight, but we’ll see. I can always throw something into the payload section if need be. For now I went ahead and epoxied the provided washer to the transition, screwed in the eye screw with some glue in the hole, and epoxied the cluster mount in.


IMG_3593To keep epoxy from clogging the guide straw I stuck a toothpick into its front end. After installing the motor mount, I was able to poke it out using another toothpick.

Nearly there! For certain values of there.




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