Tuesday, December 27, 2011

Tail Surfaces - Summer 1964

 Dennis: We started building the tail surfaces with the rudder bow. Strips of spruce were sawed 1/8" wide to laminate into the curved trailing edge.  The shape was drawn on the table and covered with waxed paper.  Nails were driven into the table about every 2" - 3" to bend the strips around.  The hardest part was that you need to quickly get glue on both sides of all the pieces so you can clamp it all together to dry.  We did this by spreading glue on one side of each strip with it laying on the table. Then make a stack of strips adding glue to the second side of the strip on top of the stack.  When the stack is all glued put a clamp on one end and then lay the stack on it's side as you bend it to shape.  It's a bit messy and easiest done with 2 people.  At least today we have latex gloves to wear doing such messy jobs.
 The ribs and spar are made from pieces of 1/8" plywood with spruce sticks glued and nailed to them.  All of the sticks were cut with the planer blade on the Shop Smith.  It was 2 years before Bill got his nifty machine back.  The Shop Smith is a worthy investment if you're building an airplane, you can even cut a lot of metal with one.  They are also available used for good prices.  We had to leave closed up pieces like the box spars for the tail open until an inspector had checked to make sure they were properly varnished.  Then we could add the second side of plywood.  They were pretty good about showing up.  I think the feds had an office at Bishop airport.
 The elevators were built the same as the rudders. Carving the laminated trailing edge to a streamlined shape is easier with a disk or belt sander starting with a very coarse grit like 24 or 36. Be sure to use a dust mask.
On the inboard end of the elevators there is some structure where the elevator attaches to the control bell crank.
The structure of the Horizontal Stabilizers is built like the fin on the fuselage, a box beam main spar and a diagonal spar made of a piece of 1/8" plywood and 2 sticks glued to it in a sort-of "C" section.
The finished woodwork for one side.
The stabilizers are attached to the fuselage with some "C" shaped fittings at the root and brace wires.  The wooden block in front of the front spar is for a pin to hold the wing when it is folded.

The hinges are just folded pieces of steel forming an open "C" shape with the back of the "C" bolted to the spar.  The pivot bolt goes through the top and bottom of the "C".  Alignment of these pins is important to the surfaces moving freely.  With all I've learned about matched hole construction and bending metal since we did this, it would be easy to get them aligned.  We had them so the surfaces moved and the plane flies just fine.

Some care was needed to get the 2 side so the hinges were all on a line with all the rigging installed.  Pete gives some simple methods for this.


We Nico-pressed all the cable ends, generally with 2 Nico-press sleeves.
Once everything was done structurally the leading edge aluminum was nailed on.  More time with pliers and a tack hammer.  That's one of the tack hammers we made in 7th grade metal shop class.  I still use mine.
Ready to Cover.

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