Saturday, August 28, 2010

Downscale A-20 Demon Build Part 2


The fins on the Demon don't overhang the rear of the main body by much.

I made a 13mm engine mount with the engine hook overhanging the rear of the mount by 1/4".

When dry fitting the mount, the model wouldn't stand upright on the fin tips with the engine hook in the way.
So a second mount was built without the engine hook, I'll just have to friction fit the engine. Those 5/20 centering rings were cut from a empty casing left over from a Semroc kit.

After the centering rings were glued in place, I realized I didn't include the Kevlar shock cord!
I'm old school and tend to fall back on the old thinking sometimes.
I decided to drill a hole in the centering ring to allow the Kevlar to be tied on.
An awl was used to get the hole started. The hole diameter was widened with a small twist drill.

I went to my stash of scrap Kevlar and didn't have anything under 150 lb. strength.

The 150 lb. Kevlar is 4 strand so I undid the wrap and used two of the strands. Simple twisting opened it up to separate the cords, re-twisting got me the two strand piece I wanted.



No knot was tied where it looped around the mount, it's simply wound under itself three times and tightened down. With a white glue fillet over the top, this Kevlar isn't going anywhere.

TRIVIA: Kevlar (insert Dupont Trademark here) was first developed as a tough replacement for the steel belts in car tires.

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