Cockpit Rail Alignment

[johntwilcox]

Instructions state I’m to align 816, Cockpit Rail so that it’s flush against the upper longeron.

As you can see in the pictures, it’s about a 1/16th from the edge at the spar junction point, and no ability to move or adjust at this point.

As it moves to the ends, both forward and back, it tapers nicely to align right on the edge.


Is this as expected?

Do I squeeze / clamp where I can to minimize the gap, or eliminate the gap, and don’t worry about the 1/16th at the 804 bulkhead junction?

Jw

 

[Mikeyb]

Mine fit pretty nice. I don’t remember how difficult it was to get it that way. As I recall there is a distance across the longerons that you have to match

 

[g zero]

I think I remember using some 2x4 and some all thread rod as a giant clamp to squeeze the fuselage together…. I got mine to hang over just a hair to file them flush after riveting.

 

[Carl Froehlich]

I’d guess you did not quite get the longeron bends correct. But, some gentle persuasion with clamps as such before drilling should get you close enough.

Side note for builders. These longeron bends have been and issue for a long time. On my first RV-8A build I found a mistake in the plans (a math error since corrected) on the bend angle. Here the cockpit rail can be a template during trial fit ups as guide. For me (on the 8A and 8) several trips between the fuselage and vice (with hammer) were required. The longerons should drop into place without any force.

Carl

 

[PhatRV]

Instructions state I’m to align 816, Cockpit Rail so that it’s flush against the upper longeron.

As you can see in the pictures, it’s about a 1/16th from the edge at the spar junction point, and no ability to move or adjust at this point.

As it moves to the ends, both forward and back, it tapers nicely to align right on the edge.


Is this as expected?

Do I squeeze / clamp where I can to minimize the gap, or eliminate the gap, and don’t worry about the 1/16th at the 804 bulkhead junction?

Jw

I remembered that I had to temporarily attach the two roll bars before fitting the side rails. This ensures the fuselage width is aligned correctly before you start fitting and drilling the side rails. I only have this picture from my build. This was showing the complete assembly. I don't have the detail pictures of the side rails. There were some minor gaps but I did the best to close the gap and used the C-Clamps to secure the rails before drilling.

 

[Jonnyb]

I have just done this bit.

You need to clamp them up so they are flush, otherwise you will lose edge distance on the upper longeron.

Two other things to note:

1, don't worry too much about edge distance on the small tabs at the intersection with the center section bulk heads and the upper longeron. The key is edge distance in the longeron.

2, don’t worry about edge distance on the F-856-1 spacer. It’s just a spacer and the screws used to hold the roll bar in place mean edge distance is out the window. Just do your best.