Saturday, October 15, 2011

Wing Details

 I haven't gotten anything done in months, but I did learn more about the wing construction. In June, on the way to the National Waco Club fly-in, I stopped in Zanesville, Ohio. Rich Wilbur purchased one of the WACO NINE projects owned by Tony and John Morozowsky. I had offered to help load the plane in Rich's trailer so I could meet him there to take pictures of whatever I could. Rich had plenty of help with him to load the trailer so I got a couple of hours to look at the wings.

The picture at the right shows something I did not pick up in the drawings. The wing walk seems a little narrow.  To fix this they widened the braces and extended the plywood for the walk about 3/4" past the rib.  It's not much but it has to help.

 The trailing edge on the wings is done with a hard wire like in WWI.  The drawings show nothing about how it was attached at the tip or the wing walk.  They use a strip of copper at the end of each rib.  The wire is soldered to the strip and it is nailed to the rib.  They did the same at the last rib and then ran the wire in a groove in the tip bow for about 4 inches.  The end of the wire then goes through a hole in the bow and gets bent back along the inside of the bow to lock it.  It's simple and it looks like it works fine.
 At the wing walk they used a piece of the steel aileron trailing edge material to solder the wire to and then soldered it to cooper strips for nailing it to the ribs.
Because the spars on the NINE are routed to reduce weight it was not clear how the ribs were attached. On the TEN the spars are solid spruce and the ribs are glued and nailed to the spars with 8 nails.  Two nails go through each cap strip into the top and bottom of the spar.  Two nails each then go through the vertical members of the ribs next to the spar.  The only area for those nails is in the routed area of the spar on the NINE.  Nothing is shown on the drawings about any of this.  From the wings it was obvious.  They used the same attachment as on the TEN with the addition of a piece of cap strip glued and nailed in place on the web of the spar.  The joy of looking at factory woodwork has been finding so many little details which we don't have to reinvent.

Thanks to John, Tony, & Rich!

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