Aileron to Flap trailing edge alignment

[snoopyflys]

I am drilling the flap piano hinges and would like to know the alignment tolerances of the flap and aileron trailing edges. I have the 1/4 in clearance between the aileron and flap. Do the trailing edges need to be perfectly straight/flush over their entire length? Or is the piano hinge clearance call out minimum the measure?

 

[Mel]

Ideally you would want them to align. It is mostly cosmetic. Flap adjustment is controlled by the width of the hinge. You can use a wider hinge if necessary. We used to have to do this quite often on the earlier kits.

Be sure that you still have sufficient edge distance. Remember the flaps carry much more load than any other control surface.

 

[snoopyflys]

Thanks, Mel for clarifying.

 

[rvbuilder2002]

Van's has a wider hinge available if that ends up being what you need.

Like Mel said, rivet hole minimum edge distance should not be compromised to get better alignment.

 

[instructor_bill]

from a post I made last December...

Painless Flap Hinge drilling

1. I took two short pieces of sacraficial hinge stock left over from building the flaps and installed them at either end of the flap with the hinge pin installed.

2. With the aileron installed and neutral, I clamped the root end of the hinge scrap to the flap brace, and propped the tipside end of the flap to the proper height (I'm installing while this is on the wing stand)

3. Once I gapped the flap to aileron with a 1/4 inch drill bit and the trailing edges of the two control surfaces matching, I used a spring clamp to hold the flap in place next to the aileron and then had my wife drill a single hole through the skin/flap brace and hinge scrap while I held the other side of the hinge firmly to the flap brace with some stiff wire.

4. Once I had one hole drilled in the hinge scrap at each end and clecoed to the wing, I ran the entire length of the scrap-- drilling and clecoing all available holes.

5. I marked the location of the hinge scraps in relation to the flap side of the hinge.

6. then I removed the clecoes holding the flap and hinges to the wing, removed the hinge pin and checked the edge clearances... on the fat side!

7. I cut the loops off of the scraps so that the hinge flange and nubs were left-- the resulting piece is flat.

8. I clamped the modified flap hinge scraps to the full-length hinge in their proper locations and transfer drilled the holes into the flap hinge at each end. To reduce confusion and the possibility of error, I pinned the full length hinge back onto the flap before drilling. I used a piece of hardwood to back up the hole I was drilling for stability.

9. I cut the hinge loops off for the two-center installed hinge pins and then clecoed the flap back on and then drilled the entire flap hinge.... drill/cleco, drill/cleco untill all holes clecoed.

The result... painless flap hinge drilling.

I should add.... The plans seem to depict the flap hinge with the recessed portion between loops flush to the edge at the flap skin/flap spar union and that's how I set the hinge. The edge distance is acceptable there too. I believe that if the hinge is set any further back onto the flap, edge distance on the wing is compromised. As it turns out, the flat recessed portion of the hinge is just about flush with the edge of the flap brace/bottom skin union as well.

 

[Charles in SC]

Be careful not to go over 1/4 inch between the flap and aileron or you may wind up with the flap to close to the fuse when the wing is mounted. This can cause headaches , ask me how I know. Mine is maybe 9/32.