Build log: Thermic 20

by Chuck August 14, 2013

Parts cut out for the pod. The LHS was has been closed on Saturday for the last couple of weeks, so I had to buy my balsa at the craft store. They don’t have 1/2-inch thick balsa, so I built up the pod from a piece of 1/4-inch and two pieces of 1/8-inch stock.


Pod parts cut and roughly shaped. Since I’m making a built-up pod anyway, I decided to create a ballast box in the nose by drilling out a hole in the 1/2-inch thick center piece. Later I’ll cut an access hatch. In the end it will be similar to the ballast box in the Thermic 30.


This is the pod after gluing up the layers. I spread glue between the sheets and then clamped it until the glue set up.


Tail boom cut and pinned in place. I cut the tail boom out of 1/4-inch stock. One of the things that I need to work on is making sure that my cuts are right-angle. The cuts that I made are at a slight angle, to there is a fair amount of glue filling one side of the joint between the boom and the pod on the port side. After I’ve attached the wing I’ll need to carefully sand the bottom of the boom when I’m rounding it to make sure that it’s symmetrical. Fortunately, the top is the factory edge, so the wing saddle and stab mount are both square. At this point the all up weight is 19 grams. It should go down considerably once I sand the pod to shape. Fillets applied and a wedge to glue in place to fair the pod into the boom. Once the glue dries it will be ready to sand to shape.



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