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Dimpling ribs under wing walk doubler ???

I have managed to dimple both top and bottom of all the main wing ribs including under the wing walk doubler's. I have searched the forum and it seems that on other models the builder was given the choice to dimple or machine countersink in doubler area. Does anyone know of a reason that the 14's would be different, or why the doubler area should not be dimpled. I tried dimpling 3 pieces of .025 and they seem to rivet together fine. I contacted Vans and was instructed to just press out the dimples and carry on. I am concerned that if I press out the dimples it may weaken the rib flange's around the rivets. Any comments or suggestions would be appreciated.

Thanks
Mike
 
You're not alone

If you read the instructions carefully it does say to dimple just the bottoms first. That's because they are calling for machine countersink on the area of the doublers. But don't feel bad: I did the same thing. Several places here it has been discussed that its ok to un-dimple (or even dimple the other way) once without compromising strength. It sounds like that's what Vans told you too.

I squeezed them out with the hand squeezer. Took 5 minutes.
 
Ditto

I did it too. I also pressed them out with the squeezer and moved on. Not a big deal. How soon I forgot after building the -9A how important it is to read those instructions very carefully.
 
Dimpling

On page 12-02, step 3 it says to dimple the bottom only. But I can not find when it says to dimple the tops, and I have fairly closely read the entire manual. It seems like it would be MUCH easier to dimple everything that needs dimpling all at once. Obviously you need to pay attention and NOT do the ribs for the wing walk, but can I dimple the others at the same time?

Do the plans call for you to use a squeezer and dimple in place later on?

I have a 24" deep "C" frame dimpler I was going to use and just do it all at once, very efficiently?
 
On page 12-02, step 3 it says to dimple the bottom only. But I can not find when it says to dimple the tops, and I have fairly closely read the entire manual. It seems like it would be MUCH easier to dimple everything that needs dimpling all at once. Obviously you need to pay attention and NOT do the ribs for the wing walk, but can I dimple the others at the same time?

Do the plans call for you to use a squeezer and dimple in place later on?

I have a 24" deep "C" frame dimpler I was going to use and just do it all at once, very efficiently?

That's what I did. I even did the wing walk and had to undo them but sounds like you've got that part figured out. I don't know any reason you wouldn't dimple the top of the rest of them.
 
The upper flange on the wing walk ribs aren't dimpled, because the doubler skin laying on top of this area isn't dimpled. The top skin is dimpled and the underlying doubler skin in the wing walk are is machine countersunk to accept the dimples in the top skin - leaving the underlying surface of the doubler surface smooth. If you've machine countersunk the doubler, per plans, you'll have to 'undimple' the upper rib flange as suggested by Vans.
 
Inboard Wing skin dimples vs countersinking

The upper flange on the wing walk ribs aren't dimpled, because the doubler skin laying on top of this area isn't dimpled. The top skin is dimpled and the underlying doubler skin in the wing walk are is machine countersunk to accept the dimples in the top skin - leaving the underlying surface of the doubler surface smooth. If you've machine countersunk the doubler, per plans, you'll have to 'undimple' the upper rib flange as suggested by Vans.

Hi Scott,

Respectfully, please reconsider your advice.
I think you are NOT to dimple the upper flanges of the number 1-2-3-and 4 ribs because the flanges are to stay flat as are the wing walk doublers, and the top skin. I think you are to countersink the top skin that overlies the wing walk doubler and the first four ribs.

Reference:

Page 14-02 step 4, second paragraph not to clearly states "machine countersink all the rivet holes that CORRESPOND to the doubler. The key word being CORRESPOND. That means the holes on the w- 00002 skin that are over the wing walk doubler holes and rib flange holes. It also directs to countersink shallow as prefered to too deep. I believe that is for strength (not to remove too much material during the countersinking for the rivets.

These directions are not very clear to me as we'll as some other sections. I was about to countersink the doublers as well until a friend stopped me.
Please correct me if I am wrong.

Full disclosure. As much as I try and ready everything several times before I drill or dimple anything, I dimpled about half of the outboard wing skin holes on that one row that it spicifically said DO NOT DIMPLE, and had to flatten them out. My Bad.

Rich
 
Last edited:
Hi Scott,

Respectfully, please reconsider your advice.
I think you are NOT to dimple the upper flanges of the number 1-2-3-and 4 ribs because the flanges are to stay flat as are the wing walk doublers, and the top skin. I think you are to countersink the top skin that overlies the wing walk doubler and the first four ribs.

Reference:

Page 14-02 step 4, second paragraph not to clearly states "machine countersink all the rivet holes that CORRESPOND to the doubler. The key word being CORRESPOND. That means the holes on the w- 00002 skin that are over the wing walk doubler holes and rib flange holes. It also directs to countersink shallow as prefered to too deep. I believe that is for strength (not to remove too much material during the countersinking for the rivets.

These directions are not very clear to me as we'll as some other sections. I was about to countersink the doublers as well until a friend stopped me.
Please correct me if I am wrong.

Full disclosure. As much as I try and ready everything several times before I drill or dimple anything, I dimpled about half of the outboard wing skin holes on that one row that it spicifically said DO NOT DIMPLE, and had to flatten them out. My Bad.

Rich

Just completed this step yesterday. Rich, I believe your assessment is exactly correct.

Nick, I'm with you. I'm scratching my head on why vans didn't give the go ahead back in 12-02 to dimple the top of the ribs (except the 4 inboard ribs). Not to big of a deal though I suppose, the pneumatic squeezer just fits but holding it is a little awkward.
 
I guess i missed this on the plans like others. I dimpled the top and bottom of all the ribs when I was on 12-02.

So at this point, I guess I will undimple the 4 inboard ribs.

The main issue is that I also dimpled the top holes of the torque tube support bracket and then I riveted it in place. So now the two top holes in this area can't be undimpled. Correct? Or should take off the torque tube assembly and undimple?

Just undimple all the other holes.

I am just wondering how many other things I am going to miss in the plans.
 
On page 12-02, step 3 it says to dimple the bottom only. But I can not find when it says to dimple the tops, and I have fairly closely read the entire manual. It seems like it would be MUCH easier to dimple everything that needs dimpling all at once. Obviously you need to pay attention and NOT do the ribs for the wing walk, but can I dimple the others at the same time?...

Yes there is a specific instruction in the plans where it says to dimple the top flange. Here it is: Page 14-02 step 7, parag 3: Dimple the top flanges of the wing ribs EXCEPT do not dimple the rib flanges that lie under the W-1 027 A and W-1027B Wing Walk Doublers.

Now, I think that this instruction is misplaced and should've been inserted in page 12-03, step 3. This deserves to be reported to Van's for future plan revisions. It would make all of us avoid sleepless nights.

Please note, I have the advantage of having other guys who went through those discrepancies before me thus avoiding me making mistakes but I hate the idea of being victorious because of someone else mishaps. I hope one day I'll be as helpful to you guys as your are to me.
 
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