January 20, 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.
This web site and the infomation contained within it are for entertainment purposes only. The opinions expressed on construction techniques are my opinions only and should not be confused with proper construction techniques. There is undoubtedly more than one way to build an airplane and some methods that I use may or may not work in any given circumstance. If there is any question please call the kit manufacturer. I love to help but I am not responsible for the misuse of any information contained on this web site.