Sunday, March 02, 2008

Pieces and Parts

Our club just bought two Blaniks and a bunch of parts from a private party. We knew that one of the ships is in really good shape and the other "needed to be assembled". Well, that was an understatement!

Apparently ship #2 was in the process of being totally refurbished. I don't know whether it was damaged, or just needed an overhaul. But it is in pieces. The wings are intact, the cockpit is partially assembled, and that's all. The fuselage and empennage are all apart. There are both old and new (shaped but not drilled) sheet metal for quite a few parts, so we can tell he bought replacements for the rebuilding process. Much of it is in very good shape - the control surface fabric all looks great. But... this would be quite a project to rebuild the ship. The club has not decided what to do with it all. We may be able to put these wings onto one of our club Blaniks that was recently crashed.

But it was interesting to look at the structure and parts as we were sorting through it and putting it all away. For example, I have never had the opportunity to see the interior of the fuselage aft of the rear seat. Handling some of the aluminum fuselage sheets and bulkheads, I was struck by how thin and flexible they are when not assembled. I had started to get some understanding of this when reading some weeks ago about monocoque ("single shell") construction. (Technically, I think the Blanik is "semi-monocoque".) When assembled into a tubular fuselage shape, the sheet becomes very stiff. When the bulkheads are riveted in and prevented from twisting in the third dimension, they become strong and stiff. Very interesting! And certain large parts such as the stabilizers, flaps, and ailerons are extremely light. When assembled, the Blanik weighs about 650 lbs (as we can tell from pushing it around on the ground) but I've never really had a chance before to see just how light these parts are individually. Not a bad way to spend a cold, unflyable day.

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