Installing the F-717 longerons to the Engine Brackets - 9 hours

Installing the F-717 longerons has been weighing heavy on my mind for some time now. Reading other build sites has noted that the edge distance at this location can be quite tight, and sometimes non existent if you follow the drawings.

Being mindful of this, I used a small piece of scrap aluminum angle to start measuring things out. Using an edge distance of 1.5 times the bolt diameter gave me a minimum edge distance of 0.28125" and marking the line on the angle at 0.500" (as per the drawings) leaves a scenario where theoretically it will work, but there is just no room for error, and for a guy doing this by hand in a garage. Its not great.




So taking the advice from other build logs, I moved the center-line of the bolts 1/16" inboard. The dimension is then 7/16" (0.4375") rather than the specified 0.500". This will allow me to have a larger margin of safety on the edge distance of about 0.373". Of course I called Van's before tech support closed, just to double check if they had concerns with my logic and the advice for me was build on.


Now its time to do the actual drilling. I started by marking out the lines and using a punch to set the center point of each hole.

Next step I drilled all of the holes to #40 so I can get a good look at the center lines drawn out on the mounting brackets below.

I then started drilling each hole to #40 and inserting a cleco. Then I started working my way up in drill sizes. #30, #25 #21 and finally ended with a 3/16" reamer for the AN3 bolt. Im really pleased with how it turned out. 



By the end of the evening, I had just enough gas left to finally complete the cutouts for the F-717 longerons. I hesitated to do these right at the beginning as I did fear I would mess up the longeron drilling. And who wants to keep cutting down multiple angles...not me.