Tuesday, August 14, 2018

FlatCat Boost/Glider Build, Part 8 - The Pop-Pod

This post covers the assembly of the FlatCat's 'Removable Propulsion System Housing', a.k.a, the Pop-Pod.
The heart of this sub-assembly is a 6 inch length of BT-20 or similar tubing.
Before any cutting and gluing begins, this is a good time to break out the CWF and fill the spiral seams.

The next procedure is to attach the motor block and retention system. 

A standard externally mounted regular motor hook can be used as shown in the plans, but I prefer to go with my internal hook system, which consists of an 18mm motor block ring and a length of .020 diameter music wire.  As illustrated below, a hook is formed to fit over the block after which the assembly is glued into place in the model's body tube. Note the slot cut in the outer edge of the ring to accommodate the thickness of the wire.




Once the assembly is dry, an expended motor casing can be inserted into the body tube and the wire bent over the end and clipped.  Here is a pic of the completed assembly.


Now it's time to make the pylon.
Another 4 inch piece is cut from the 1/4 x 1/2 balsa stock, and the ends cut to a 45 degree angle as shown in the plan diagram.


Now for a little bit of shape-sanding work. The first procedure is to round-over the leading and trailing edges.


Next, a piece of sandpaper is wrapped around an expended motor casing, and a concave curve is sanded into the long edge of the pylon.  This provides a much better contact surface for gluing to the body tube.


Which, , of course, is the very next step of the build.


Killing two birds with one stone (has anybody ever really accomplished that feat?).

The Piece-X is double glue-joint attached to the pylon at the position, and orientation (!) specified in the plans.  At the same time, some glue fillets are applied to the pylon.  The whole assembly is set aside to dry.


Over the course of the next couple of days, the pod pylon will get the usual application of CWF to fill the grain.  Gotta keep things pretty, you know.

Finally, the launch lug is attached.  This is a 1-1/2 length of 1/8" lug, with seams filled.  Yep, I do that even with boost gliders. 
When I became a BAR a couple of years ago, I promised my significant other that I would not clutter up the house with 'junky' looking rockets like I did back in the old fleet days, so every project I build now gets cleanly crafted and finished.


The pop- pod assembly is ready for primer and paint!

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