flap brace cs or dimple?

[Nihon_Ni]

Thanks Carl. Yes, the flap brace and bottom skins are both dimpled. My bottom skins are riveted to the wing ribs and both spars, but they aren't riveted to the Flap Brace yet.

There's a note on DWG 14B to "Dimple FL-802PP [Flap Skin] and machine countersink FL-803PP [Flap Spar]" but if there's a similar note about the Flap Brace, I missed it. The instruction to "Drill, deburr, dimple where required, and rivet the W-721 flap brace (DWG 14A) to the rear spar" were pretty clear, so I did exactly that when I got to that step.

Any idea how Van's expects builders to mount the flap when they follow the plans for this step? Your solution is a good idea that I hadn't thought of. I was considering just dimpling the hinge and riveting it together.

You're really making progress on your build! I'll have to stop in and see it next time I'm on the field.

Rob

[Carl Froehlich]

Dimpling the hinge is not an option. Still recommend a call to Van’s before proceeding.

Come by the Dogwood Aircraft production site whenever you want.

Carl

[Carl Froehlich]

Another option that might be easier and does not require taking the hinge off the flap:
- Mount the flap to the wing as discussed above.
- Use the now drilled hinge as a template to drill the holes in the 1/2” wide .032” aluminum strip.
- Machine countersink the holes in the hinge to accept the dimples in the flap brace.
- Use the non-dimpled and non-countersunk aluminum strip as a backing to the hinge rivets.

Here even though you countersink the hinge, you are adding a backing strip to the hinge to hold the rivet. So the hinge ends up sandwiched between the flap brace and your added aluminum strip. As you did not change the height of the hinge relative to the wing, you need not change the hinge attachment on the flap.

Carl

[rvbuilder2002]

My recommendation is similar to Carl's but less steps.

Fit the flaps and match drill the holes in the hinge.

Remove the fwd hinge half from the flaps.
Cut some .032 thick strips (preferable on a metal shear so that they are straight and flat) the same length and width as the flange on the hinge.
Match drill the doubler strip using the hinge.
Machine countersink the hinge
Rivet together with the hinge sandwiched between flap brace and the doubler strip.

[Z-EDD]

Originally Posted by Nihon_Ni

Did I miss a secret message somewhere to disregard the plans for this step and countersink instead, or did I misread the instruction?

You didn't miss anything, but this is a first indication of how sparse and even miss-leading the instructions can be from now on!

In your position with the bottom skin riveted on I would go ahead and just plan on countersinking the hinge and using a backing strip as suggested earlier in this thread. You don't really need the partially set rivet trick, if the lower flange of the brace was correctly adjusted then the skin dimples should nest into the brace dimples and will be held sufficiently in alignment. I have just today updated the photo links in my build thread on this, see here:http://www.vansairforce.com/communit...=109734&page=7

Having your brace dimpled will make it slightly more difficult to clamp the hinge but it should still be doable.

[Nihon_Ni]

Thanks for all the advice and input. I ended up countersinking the flap hinge and adding a backing strip. I'm happy with the results.

Rob