What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Flap pushrod holes

O

OLDSAM

Well Known Member
The F-776 bottom skin, and the F-623 corner ribs have a small pilot hole that is to be enlarged for the flap pushrod holes. This is noted on the skin detail on drawing 28, but no size is given to which the holes should be enlarged. I expect the size and shape of the hole to be adjusted later when installing the flaps due to the non-linear travel of the pushrod, but does anyone have any experience as to how big they should made initially?

Thanks for the help y'all.
 
Start with .75 diameter, just enough to clear the bearing at the flap end. Eyeball the center with the flap raised 'cause the fuse pilot hole may be a tad off. The hole in the fuse side need be no bigger than what clears the bearing. The bottom skin gets a much bigger hole, more of a slot, extending forward of the bearing center because the pushrod moves forward as the flap is raised. The slot must be shaped to accommodate the pushrod as the actuator moves through its arc.

John Siebold
 
I'm just now building the cabin floor, so am not yet in a position to examine the fit and position of the flaps relative to the fuse, just need to get an idea of how much to drill out the pilot hole prior to riveting the bottom skin to the ribs and bulkheads, in order to have something to work with later when the fuse sections are assembled. Is 3/4" still a good size for that? That will take it about to the edge of the bottom skin.
 
RV7ator hit the nail on the head. I was a bit worried about this part, but it was quite easy. I first drilled it to 1/2" or so, then ground it open using a dremel until I had a nice, smooth opening that allowed the rod end bearing and rod to arc through their motion.

I left the flap hinged in place and rotated it up periodically to test the fit. Other side went twice as fast as the first.
 
I don't remember drilling it at all.

Per Johns post above, mine was similar:

When the flaps were on I put the flap bearing on the flap and eyeballed the place to start grinding a clearance hole for the bearing by using a dremel and the coarse sanding cylinder. No hole needed if you start cutting at the corner of the fuselage. If you are built correctly, you don't need to clear the whole bearing body in the sideskin hole, only the standoff stem. Once I had that fit well, I installed the pushrods and moved the flap up and down to see where the hole in the bottom skin needed to grow. Grind, check, grind, check, etc.

If you are patient, you can finish with a minimalist hole.

Direct link to pics of mine
 
Last edited:
Was blind, but now I see.

OK, I see it now. I didn't realize that the hole, or more accurately the cutout, went around the bottom corner of the fuse, thought it was only in and out of the bottom. As they say, a picture is worth a lot of words, especially when you get old and feeble minded. Thanks all of you for the responses.
 
Just finished my opening

You can check out my build log if you are interested. My openings are ear shaped on the bottom, triangular on the side. I used the method mentioned above; connect pushrod, check clearance, remove, use Dremel to enlarge and repeat.

http://www.mykitlog.com/sdahrens
 
You must log in or register to reply here.
Back
Top