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Wing walk doublers

FlyBoy8

FlyBoy8

Active Member
The instructions say the doublers should overhang the rear spar by about an inch but if they are cut to 26" long as described they don't overhang at all.
I'm confused again.

I just looked at the plans again. Its difficult to see the doublers in the drawing but it does show that they don't really overhang the rear spar at all and also reiterates the length of the doubler as 26"
 
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Mine are the same. I cut them to length and they don’t over hang. I took the opinion that I have built them to the drawings.
 
Overhangs on -6

The plans for the RV-6, which has essentially the same wing as the -8, shows the doubler overhanging the spar (dwg 21). If you think about it, the overhang is going to add strength to the surface for the extra inch or so and there doesn't appear to be any advantage to trimming it flush with the spar, other than some minimal weight saving.

Note R7: 27 3/4 was 26.

There's lots of discrepancies between drawings, drawings and instructions. Sometimes you have to look at what it's trying to achieve and make your best decision.:eek:
 

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The -7 plans do not have the doubler overhang the rear spar. The doubler connects to the top flange of the rear spar, but not the front spar on the -7.
 

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Good answers fellow RV'ers. I admit i'm a bit partial to the overhang adding strength route. I think i will cut them to 27", do the match drilling, and shoot vans an email for their opinion. I can always trim it down to 26" if needed.

I'll post the response from Vans when i get it.
Mike
 
I can’t see a problem with letting them overhang to gain a bit of strength in that area, unless they interfere with the flap.
I cut mine to the dimensions called out in the plans and it didn’t overhang, nor do the plans show it overhanging. I wasn’t about to order in a load more aluminium to redo them.
The only thing I would point out is that if someone steps on them in that spot, no amount of overhang will stop the damage as there’s no support underneath the wing skin in that area. Any part of the wing skin aft of the rear spar needs to be part of the “no step” area to stop damage to the skin and flap below it.
 
Here is response from Vans support...

Either way works. I left mine long and a passenger stepped aft of the spar and bent the doubler down, but the skin didn’t appear bent. The doubler really messed up the flap, so I recommend cutting the doubler off at the aft edge of the spar.
 
Trying to remember 30 years ago. I seem to remember that I initially built with the overhang and had interference with the flap leading edge. This caused me to go back and trim off the overhang. Not too easy after completion of the wing.
 
If you choose to leave your wing walk doublers a little long, do yourself a favor and consider if/how they will interfere with the nutplates on the inboard side to which the wing root fairing will attach. In my case I found had to fabricate a little spacer to allow the nutplate to lay down flat... an easier solution would be to trim the inboard corner of the doubler before assembly.

20210731_nutplate.jpg
 
Many moons from now when you install the Wing Walk anti-slip material on the top of your wings, it should be installed with the trailing edge just before the rear spar. Instruct your passengers to only step on the black stuff (they won't... but it's worth a try, to preserve the skin from getting kinked behind the spar).
A slight overhang of the doubler is to help prevent the kink.
 
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