Stephan's Sonex #1627 Builder's Log

I decided to finish up the elevators this weekend. I updrilled all of the holes to final size and also cleaned up the overlap on the elevator root assembly. I had cut the elevator skins according to the size and angles required, but the control horn assembly that was provided by Sonex caused the skins to overlap by almost 5-7mm, with the overlap being more pronounced near the tips. I filed down the excess so that the elevator skins were flush with the edge of the root assembly ribs. 

All that remains now is to debur, polish and prime the ribs and to rivet the bottom portion of the elevator. The top portion will have to remain cleco-ed until the MD-RA inspection is complete.

I worked on installing the left hinge on the horizontal stabilizer today. I again used the elevator as a guide and added the end-stop to ensure everything is flush with the edge of the stabilizer.

I did not have a piece of hinge left that spanned the entire required length so I made it out of two pieces instead. I had previously confirmed with Kerry at Sonex that this was acceptable, and he indicated that as long as the hinge pin spanned the entire length, it wasn't a problem.

I positioned the elevator with the hinge pieces in place and drilled and cleco-ed everything together. 

I worked on installing the right hinge on the horizontal stabilizer assembly today. I wanted to use the elevators as a guide to determine the correct position of the hinge, but the elevators were still all cleco-ed and these clecos interfered with the installation, so I removed them and used #4 stainless steel screws to temporarily fasten the hinge half on the elevator. I did this for both the left and right elevators. I marked up the other hinge half using a ruler and installed the hinge onto the elevator using the hinge pin. I then added an end-stop using a piece of channel stock to allow me to ensure that the elevator is installed flush with the edge of the horizontal stabilizer. I then positioned the elevtor in place and lined up the hinge to the correct position and drilled and cleco-ed everything in place. 

There is about 1-2mm of play laterally with every hinge, and when I installed the right elevator, I had it pushed all the way to left. This means that the elevator can actually move 1-2mm to the right and scrape the end-stop, so I moved the hinge down 1-2mm to avoid this. I wanted to make sure that when the fiberglass tip is in place, the required minimum gap is maintained even if the elevator slides latterally a little.

I noticed this problem after drilling the first hole, causing it to be off a little. However, once up-drilled, the issue is no longer there. Hence the 1/8" (copper) cleco in the corner of the first picture below.

I cleco-ed the entire horizontal stabilizer assembly together and marked the centre line on each of the ribs as well as the the forward spar. Throughout the process, I used a heavy piece of metal from my bending brake to hold down the ribs and assembly while drilling and cleco-ing everything in place. I routinely checked to make sure that the ribs were perpendicular with the table surface using a straight edge. I proceeded to lay the skins over the stablizer assembly and lined up the pre-drilled holes in the skins with the centre line on the ribs and forward spar assembly. With the exception of the the longest rib, all the holes lined up reasonably well with the skin. 

The longest rib did not line up correctly. It turns out that the attachment bracket position was a few millimeters off and this caused the angle of the rib to not match up. I left this issue for now and proceeded to drill and cleco the skins in place. I did this for the left and right side before turning the whole assembly over and drilling and cleco-ing the other side. 

I up-drilled everything with the exception of the tips and the edge where the hinge will be positioned.