Home > VansAirForceForums

- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

Old 11-20-2012, 02:47 PM
tyvaf01 tyvaf01 is offline
Join Date: May 2012
Posts: 19
Question flap brace cs or dimple?

does the flap brace receive dimpled or cs holes where it matches the hinge?
I think it is not allowed cs or dimple the hinge as I have recently seen
at one builders log blog!the instructions not really mention it.
Christian Muigg
BX-2 CHERRY flying
RV-8 #83266 empenage and wings finished,fuselage in progress.
aircraft engineer EASA B1/C
Reply With Quote
Old 11-20-2012, 05:46 PM
smiller smiller is offline
Join Date: Feb 2008
Location: Hillsboro, Oregon
Posts: 102
Default Countersunk

It would appear that it should be countersunk, which I discovered after dimpling. :-( I'm building a -7A and the manual is definitely lacking in this area! But see for example I will probably do as written there and flatten out my dimples and countersink.
Shannon Miller, CFI/CFII
RV-7A Fuselage
Reply With Quote
Old 11-21-2012, 02:53 AM
kiwipete kiwipete is offline
Join Date: Oct 2007
Location: Birmingham United Kingdom
Posts: 367
Default One of each

I found the same on my -7 when I built the first wing I dimpled so just counter sunk the hinge to allow. On the second wing I changed and counter sunk the brace. Really it makes no difference. I wouldn't however flatten and then countersink.
Countersinking the hinge is just a little more tricky.


RV7 G-PBEC Flying
RV10 Finishing
Reply With Quote
Old 11-21-2012, 09:11 AM
briand's Avatar
briand briand is offline
Join Date: Mar 2006
Location: Grand Rapids MI
Posts: 741

The skin gets dimpled, the brace gets c-sunk and the hinge half gets neither.

Think about it, why would you want to have to make the .040 brace dimples fit in a c-sunk hinge when if you c-sink the brace all it has to fit is the thinner skin dimples. Plus the c-sunk part gets sandwiched between two non-cs'd parts.
Reply With Quote
Old 01-05-2013, 12:42 PM
grayforge's Avatar
grayforge grayforge is offline
Join Date: Dec 2011
Location: Kirkland, WA
Posts: 879

Old thread, but some more info:

Vans recommends that after this not uncommon slip up (dimpling the flap brace), you can flatten the dimples (once), then countersink them. This is what I did. It was a hassle to do this, but I wanted it to be right. My wife had to help pry the brace away from the skin to give me access for countersinking since the brace was already riveted to the wing spar.

Another option Vans says is acceptable is to countersink the hinge and back it up with a strip of .025 sheet.
Speed Is Life

VAF Donation made: 3/31/2017, My RV-7A Build Log
Reply With Quote
Old 10-26-2017, 09:43 PM
Nihon_Ni's Avatar
Nihon_Ni Nihon_Ni is offline
Join Date: Jun 2011
Location: Fredericksburg, VA
Posts: 271
Default I followed the plans be apparently still did it wrong

Reviving this old thread yet again.

I'm at the point where I'm ready to attach the flaps to the wing, but I can't find any instructions on how to accomplish this (other than the choice of hinge pin methods). As I started digging around here on VAF for info, I discovered many builders countersunk their Flap Brace rather than dimpled it. I dimpled mine per this statement on p 7-9 of the plans:

Drill, deburr, dimple where required, and rivet the W-721 flap brace (DWG 14A) to the rear spar.

The forward side is riveted to the rear spar with standard rivets, and the only other holes in the brace are the aft ones that attach to the bottom skin, sandwiched between it and the hinge for the flap. If these holes aren't the ones that should be "dimpled where required," then what holes is this instruction discussing?

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

Also, I can't find any instructions on how to mount the flaps as far as alignment. DWG 9A shows a 1/4" gap between the aileron and flap, but that's all I can find. I presume they should be even with the trailing edge of the aileron, but I can't find that written anywhere. The section titled "Attaching Flaps to the Wing" only discuss two options of securing the hinge pin. I've spent all evening scouring the plans and drawings for clues, but I can't find anything else. Can someone point me in the right direction?

Rob K
RV-8 under construction as of Sep 30, 2012
Tail kit completed on Feb 8, 2012 (180 hrs)
Wing kit mostly completed, fuselage under construction as of March 6, 2014 (750 hrs)
Paid up for 2018

Last edited by Nihon_Ni : 10-26-2017 at 09:53 PM.
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -6. The time now is 11:27 AM.

The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.