chepburn

chepburn

Well Known Member
Hi all,
I am in the process of drilling my fuselage longerons, and I have been looking at the roll bar - F816A L/R 1 canopy rail and the F887 L/R 1 longeron connection.

I know I have to bend the roll bar to 'fit' the gap, but, putting an AN bolt throught the inside edge of the roll bar into the F816 L/R 1 canopy rail will result in a pretty small hole edge distance for the AN bolts going through the upper longeron. It looks to me like the F816 skin has to move outboard about 3/16 of an inch to get those holes into the center of the longeron....

Now the kicker, the prepunched holes in the 816 is putting the holes too close to the edge of the longeron in my opinion. How did everyone else solve this problem? (This is the 'new' fuslage kit BTW) If I move the rails closer to the outside edge, the predilled holes on the 804C center bulkheads way out of line (1/8 inch) Do I just push realllllllly hard, or what?

Thanks for the help........

Chris
 
Cockpit Rails

Chris,
See this thread for a discussion of the cockpit rail-to-longeron fit issue:

http://www.vansairforce.com/community/showthread.php?t=30441&highlight=cockpit+rails

My seat support looked too narrow, but I discovered that the side skins were pulled away at the top as described in this thread. Some things that helped:

1. Cleco the cockpit rail spacers on the cockpit rails and backdrill all holes to 1/8." This will let you see how things are really lining up when viewed from the top.

2. Cleco the cockpit rails in place per the plans. If the rail edge won't come flush with the side skins at the spar bulkheads you may need to take off the side skins and adjust the flanges at the top to get a good fit. This should help the fit on the roll bar.

3. Use the ratchet strap technique to pull the side skins tight at the seat support. Use some 2x4 blocks at the bottom so the ratchet strap doesn't kink your bottom skins. Cockpit rails should now be flush with the side skins. Drill and cleco per the plans. Look through the holes you backdrilled in the rails and the bolt holes should be lined up. Now you can backdrill them from underneath.

Hope this helps,
Mike
 
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Thanks for the info,
That thread appears to be a discussion on the front seat back support, which also looks like its going to be a challenge.
My issue is with the front roll bar, and it looks like I am going to have to apply some clamping pressure to the 804C center bulkhead to squeeze the 804C in a bit....I am just kind of surprised that this might amount to over 0.125 inches of travel...
I am worried that if I adjust the flange on th 816 rail, the two holes for the front roll bar will no longer be lined up in the vertical.
 
Same Issue...

It's really the same issue...the cockpit rails must line up with the longeron (overlapping the side skins) from where the rollbar attaches above the F804 bulkheads all the way aft.

My plans call for using a ratchet strap to clamp the skin against the gear towers, so Van's knows about this technique.

Bottom line is that the upper edge of the side skins must be tight against all the bulkhead flanges-the curve at the upper fuselage along the cockpit makes this a challenge so some clamping pressure is required.

When I referenced the spar bulkheads I should have said F804 to be clear (but didn't have plans in front of me).

Mike
 
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