llavalle

llavalle

Well Known Member
I'm working on my rear wing spar.

I just completed the match drilling, C/S and priming of the 4 doubler plates.

For the 2 that had to be drilled from behind, namely W907D and W907, I've got a question :

The spar flanges are dimpled, I get that (I already dimpled the inboard end as specified by the instructions). My question is : is it dimpled all the way?

If it is, I sure need to dimple the upper flange of both doubler plates... Am I correct in assuming this? The only other option would be : dimple all but where are the doubler plates. On these holes, machine c/s since there is a doubler plate...

Which one?

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Thanks!
 
The instructions have you "ream out" all of the rear spar dimples with a deburring bit after you dimple them, to allow the skins to sit more flush. For those doubler plates, I didn't dimple the spar until the skeleton was already riveted together & match-drilled with the skins, so I tried it two ways:
1. Dimple both pieces together, then "ream" them with the deburring bit like all the rest.
2. Countersink the holes with a microstop cage to an appropriate depth (test with a scrap piece the same thickness as the wing skin).

I was happier with the countersunk holes, and there is enough thickness to accommodate the countersink, with the doubler plates. Depending on the shape of your squeezer yoke, you may find that it's difficult to get a dimple die into the doubler/spar stack, since that flange is bent past 90°, as well.

Either dimpling or countersinking those holes at this point will mean they won't be match-drilled with the skins in place, which may or may not be a problem.

Good luck!
 
jwyatt said:
1. Dimple both pieces together, then "ream" them with the deburring bit like all the rest.
2. Countersink the holes with a microstop cage to an appropriate depth (test with a scrap piece the same thickness as the wing skin).
Click to expand...

Alright, so I'd better drill and dimple them right away, before assembly. I might not be match drilled with the top skin but I feel it will hold better with a dimple in both pieces.

I will only dimple a couple of holes :
1)On the top flange, where W907D sits
2)On the top flange, where W907E sits
3)On the top flange, where W907B prevent access, as indicated in the instruction manual.

But before doing all this, I'll contact Vans for an opinion.

Thanks
 
They said to dimple both piece together(after riveting) and ream the holes for a better fit.

The only place we should dimple before riveting in on the inboard end because afterward, it will be impossible.

FlyingArcher said:
Bonjour Philippe

Did you get an answer from Van's about this choice? I'm at the same point asking myself the same questions:confused:
Click to expand...
 
W-921 and W-924

Hi Philippe,

While I was at looking at the plans to mask not-to-be-riveted holes in the rear spar assembly, I noticed some rivets called out on W-907-D and W-907-E for which I had no hole drilled yet. They are the ones that will be used to attach the aileron and flap gap fairings.
Looking at the manual about fairings installation, they mention that some holes should be match drilled from the spar to the fairings.
Well, in my case, it seems to be the opposite, so I decided to match drill the holes from the the fairings to the W-907-D&E and the rear spar, as well as dimple the 3 most inboard flap fairing holes.

Did anybody do the same? :confused:
 
FlyingArcher said:
Well, in my case, it seems to be the opposite, so I decided to match drill the holes from the the fairings to the W-907-D&E and the rear spar, as well as dimple the 3 most inboard flap fairing holes.

Did anybody do the same? :confused:
Click to expand...

Yep, I saw those. When I read the manual, I think it said that the spar should be match-drilled using the pattern in the fairings... as far as I can remember.

For now, I left those un-drilled : I'll just drill them later, using the fairing as a guide.

I'll re-read this part in the instructions tonight.
 
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