RV-7 Lower Wing Inspection Covers TOO thick?

[jackking123]

So nailing up the lower skins really getting a good fit of access / inspection covers. The cover thickness is greater than the joggle depth, so it sits appears proud of skin slightly.
I did not screw then down but seems so?

Question is this normal cover fit for RV-7???

BTW FYI mine is an early RV-7 kit? Did they make a change here? May be Van made the joggle deeper. My first RV build (RV-6) I recall there was a doubler around the wing skin cutout, where the nut plates went. The cover was same thickness as the wing skin, so nice flush fit, nominal gap. With RV-6 joggle you have a little gap all around for bend radius.

 

[PhatRV]

It seems like your RV7 inspection covers are very much the same as my RV8, where the wing kit was delivered in 2018. I don't think there is any thing wrong with it. There is no doubler for my RV8, just a joggle fit as with all the access panels. The exception is with the stall vane access panel and the tail trim cover where doublers are used.

Can you post a picture of the panel fitment?

 

[jackking123]

It seems like your RV7 inspection covers are very much the same as my RV8, where the wing kit was delivered in 2018. I don't think there is any thing wrong with it. There is no doubler for my RV8, just a joggle fit as with all the access panels. The exception is with the stall vane access panel and the tail trim cover where doublers are used.

Can you post a picture of the panel fitment?

Thanks PhatRV. I feel better. I got the screws out, cranked it down. Low and behold it's better (pun intended). flush on spar and almost flush on sides, may be a few thousands proud. Corners sticks out more, say 0.005" (eye ball measurement).

Tad tall in corners, might benefit from tweaking. I am tempted to:
Use sheet metal seamer pliers out and bend the joggled flanged down just a tad.
Cover, roll/crimp edge down (imperceptible tweak)
Remove some metal on back side of cover.
Counter sink the dimple hole in skin to assure cover mating flush

As you said (and I bothered Van's) it is normal. Cheers

 

[PhatRV]

These look like all underwing access panels of the RV8s I saw when I was building. In the last picture, the corner seems to stand proud. Are you using the correct nutplate? and the screws are torqued correctly?

 

[scrollF4]

Show us a picture of the wing hole without the covers in place. I wonder if the joggle is insufficiently joggled, making the panel sit proud.

 

[uk_figs]

These look like all underwing access panels of the RV8s I saw when I was building. In the last picture, the corner seems to stand proud. Are you using the correct nutplate? and the screws are torqued correctly?

Worth checking this as the dimples in the panel sit in the nutplate and could be sitting on the nutplate versus the joggle. These panels come off every condition inspection so will get a fair amount of on/off use.

 

[DanH]

Good grief Charlie Brown. Pick up a micrometer. If the plate is the same thickness as the skin, the issue is fitment.

 

[Karetaker]

Good grief Charlie Brown. Pick up a micrometer. If the plate is the same thickness as the skin, the issue is fitment.

 

[jackking123]

Thanks for the replies.

1) Nut plates per plans.
2) Pic of whole wing not needed (I think)
3) Dimple dies are quality Cleveland polished/chrome, fit of dimples are good
4) Screw torque? Tight and the plates fit nice where screws. I use German torque method, "GUT" method, "Gut Und Tight". Ha ha
5) Cover is flush on the spar and flush with fuel tank and leading edge).

6) Got feeler gauges and fingertips, I est the sides 0.014" proud & corners more.

a) Fixes, for sure chamfer the cover inner edges, side and aft, assure it's not riding the joggle on wing skin.
b) Check "dimple to dimple" fit, make sure dimples not holding cover up. Correction remove some mat'l.
(NOTE Dwg Sht 12 says dimple countersink, this could be fix, I would never counter sink 0.032 skin for a screw alone, but you can touch up dimple with countersink bit to improve fit.)
c) Corners no screw to pull tight. Correction, bend cover corners down (very slightly) to make it fit better
d) Skin Joggle may not be completely formed, manufacture "spring back", handling shipping skin, un-bent joggle. Correction, check & ltweak

RV-7 has total of 6 access covers on lower wing skins. Two inner skin and one outer skin. I have only tried one cover.
I'm about to rivet the bottom skin on; just making sure (QC) ready, not issues to address. The cover fit can be massaged with skin on, so no big deal.

I will report back if any revelation in the fitment issue. If you have things you did to get less than flush access covers flush let me know.

 

[PilotjohnS]

I remembermine being proud too. I rounded the edges of each inspection plate to reduce the “step” and allow the eventual paint to stick better and not have the paint try and cover an abrupt edge. I figure the covers will take a lot of abuse over the life of the plane. Just me. I also stamped them with their location before painting so the paint would fill in the letters a little bit

 

[rvbuilder2002]

I have seen a lot of sub par dimples that were made with quality tools and dimples dies, and the builder thought they were good.

 

[rvbuilder2002]

I remembermine being proud too. I rounded the edges of each inspection plate to reduce the “step” and allow the eventual paint to stick better and not have the paint try and cover an abrupt edge. I figure the covers will take a lot of abuse over the life of the plane. Just me. I also stamped them with their location before painting so the paint would fill in the letters a little bit

This is probably at least part of the problem.
The joggle for the cover is formed on the same CNC punch machine that does the rest of the punch work on the skin
The dimension of the resulting joggle has always been just very slightly smaller than the design dimension of the cover.
A heavy coat of paint on the skin and the cover makes this even worse.
If someone wants a best possible fit, they need to reduce the size of the cover by a small amount on the three sides that interface with the skin joggle.

 

[PhatRV]

I have seen a lot of sub par dimples that were made with quality tools and dimples dies, and the builder thought they were good.

I remember to make a good dimple on the thick sheet metal, I needed at least a couple of whack on the C-Frame dimpler.

 

[jackking123]

I remember to make a good dimple on the thick sheet metal, I needed at least a couple of whack on the C-Frame dimpler.

SUCCESS.... Thanks PhatRV, I did this on my own yesterday, just saw your post. Ha ha.

Dummy (me) for some unknown reason under dimpled the covers. They looked fine to me.
I re-did the cover dimples and now it fits pretty pretty pretty perfect.

Typically for dimples, I use my trusty C-Frame Dimpler (manual squeezer for small stuff, e.g., rib flanges). I built up a wood work surface so dimple die is almost flush with work surface, slight above. I use an "aerospace" hammer (not a rivet gun) to TAP, 3 taps on die set (shaft), 1 or 2 light/medium and a third, firm. Typically, I know it's set by sound. You can hear the sound change when the dimple has fully set on last whack, might take a 4th tap. Don't want to over do it either, but can't be too timid. I under-set the cover dimples. Doha! Once I went over them again... FLUSH BABY... Thanks everyone. Such a simple fix. When doing skins I used a light and you could see the ones that were slightly under and needed another tap under the dimple die.

Lesson: Did not panic, walked away, didn't do anything drastic, solution presented it self... in part due to help from Vans Airforce Forum dot Net members.
A little embarrassed, but hope this might help others in the future.