February 3, 2021
I really spent a lot of time scratching my head while trying to figure out how to get those elevator stiffeners fabricated and laid out. So I thought that I would write a little note on how I did it.
The first step is to layout the locations on the elevator skin. I started by clecoing the spar to the elevator skin and drawing a line along the trailing edge of the spar. Next mark the position of the stiffeners with the dimensions from the drawing along this line. Now use a plastic triangle and draw the stiffener lines perpendicular to the spar at each mark.
Next we need to figure out how long they need to be. I took a piece of 3/16" rod and put it inside the trailing edge bend of the elevator and used that as a reference to measure from since the plans call for a 3/16" distance from the trailing edge. Now fabricate the stiffeners according to the plans with these lengths. Don't forget the 1/8" clearance from the spar.
Next we need to place that hole that is 3/4" from the trailing edge. It looked to me like that measurement was being taken at a right angle to the trailing edge of the elevator, which is NOT perpindicular to the stiffeners so I just used a scale on the inside of the trailing edge bend and tried to hold it as square to the trailing edge as I could until I had the 3/4" mark instersecting the line for that stiffener and marked it. Then I layed that stiffener along that line and transposed the measurement to the stiffener. I did this to each stiffener and it was probably overkill but I nailed that dimension. Now the question is whether or not that dimension is critical. Oh well that is how I did it.
To lay out the holes in the stiffeners I did it the hard way. I just marked the hole at each end and measured the distance between them and then found out how many rivets I needed to keep about a 1.3" spacing. The plans call for 1.5" but one extra rivet won't hurt. I just divided with my calculator and marked it out with my scale. It was tedious and if you have a rivet fan I would suggest you use it here. I haven't decided to buy one of those fancy things yet. Since the rest of this kit is supposed to be pre-punched I don't think I'll have that much of a need for one. If I was still building a -6 I would have bought it at this point.
I drilled about a 1/16" pilot hole for each rivet in the stiffeners on the drill press.
The stiffeners are supposed to overlap each other by 1/8" I got this overlap when I drew centerlines for the stiffener holes onto the skin. Just adjust one line 1/16 of an inch to port and the other 1/16 to starboard. Then put the skin on a good flat surface (I used a hollow core door and it seemed to work really well), put the correct stiffener on the correct line and drill from the trailing edge forward putting a cleco in every hole right through the door to hold it down.
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