Fuel Tank Cover

[Bearhawk Builder]

I find the spacing of the fuel tank cover screws on the drawings, 16 total, but what size screws are used to fasten the cover down? Dakota full wing kit. They sent in the wing package 10 each of -3 nut plates and 6 each U type tinnermans. This suggests 5 -10 screws for the front and rear and 3 PK's for each of the sides, is this correct? I'm also assuming that the top wing fairing will line up with the inboard screws of the tank cover? Any suggestions here are appreciated. Thanks again.

[Bearhawk Builder]

Anyone know what size screws to hold down the tank cover?

[cubpilot2]

10-32 x 5/8” max. truss head phillips, front and rear. (Any longer and the screw may hit the spar caps. ) #10 PK X 1/2”on sides. This was as original.
Usually wing fairings will be just under the tank cover and just butt up to the screws. Have seen some get holes later.

A lot of people are putting nut plates on the rib flanges vs. using the tinnerman clips so everything is with machine screws. Then they don’t work loose so easy.

[mike mcs repair]

10-32 x 5/8” max. truss head phillips, front and rear. (Any longer and the screw may hit the spar caps. )

oh, you learned that max length lesson the hard way too???

[cubpilot2]

oh, you learned that max length lesson the hard way too???

[Steve Pierce]

I thought Piper called out 10/32- 1/2" screws on the leading and trailing edge of the fuel tank cover. That is pretty unnerving to find those wallowed out craters in the top of the spar caps.

[cubpilot2]

I thought Piper called out 10/32- 1/2" screws on the leading and trailing edge of the fuel tank cover. That is pretty unnerving to find those wallowed out craters in the top of the spar caps.

Yep: That's why I said "max". It seams that people will grab whatever is handy and throw in there; not thinking that it would be an issue. 1/2 is best. I just replaced a spar due to a couple of really deep gouges there; and some rib attachment screws that were drilled into the bead section on the spar. (just asking for cracks to start).

[mvivion]

Dakota wing? I’d call Mark at Dakota.

MTV

[Steve Pierce]

Dakota wing? I’d call Mark at Dakota.

MTV

Asked and answered really. The dimensions and size nut plates are in the Dakota Cub drawing. The rest is pure Piper. I would hate to build one of these without examples or pictures around to look at. Here are the tank covers installed with wing root fairings. Seen the fairings over the covers and screws but that is wrong and wears holes in the fairings.


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[jon s. blocker]

Thanks for the info guys, I'm at the stage of getting the wing tank cover set up on my homebuilt wood spar wing. I have a full wrap leading edge from Dakota Cub, but I am having troubles fitting it to the spar. May have to resort to cutting the bottom "lip" off the leading edge and just carry it to the aft edge of the spar and attach it as was done on the original J3 wing. The leading edge sheet metal is actually a little bit too long , (top of spar to bottom of spar, making the D section). Being experimental, at least I have options. Jon

[RaisedByWolves]

Stop by and take my old tank covers with you and drop em off when your done. I’ll leave them out. Working at another airport tomorrow. South end of the runway is wet, land on the north half.


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[Bearhawk Builder]

Asked and answered really. The dimensions and size nut plates are in the Dakota Cub drawing. The rest is pure Piper. I would hate to build one of these without examples or pictures around to look at. Here are the tank covers installed with wing root fairings. Seen the fairings over the covers and screws but that is wrong and wears holes in the fairings.


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Steve, what is this Dakota drawing you speak of? All I have is a 3 page rib install instruction sheet, no drawings. The two small drawings on line don't show much, mostly for rib repair.
The drawings I've been using have been the Northland and Christian's site and this area is not detailed very well.
There may be, likely is, something I'm missing but you all have answered that question well. A LOT of time is spent searching the drawings to see how things are assembled and with what hardware. I wish that was more thoroughly called out in the kit. Mike and Keith have been great at getting questions answered but sometimes it takes some time to get an answer.

Tom, if that's for me I have the hole spacing and size, it was just the fastener size that had me stumped. Thanks anyway.

[Steve Pierce]

Steve, what is this Dakota drawing you speak of? All I have is a 3 page rib install instruction sheet, no drawings. The two small drawings on line don't show much, mostly for rib repair.
The drawings I've been using have been the Northland and Christian's site and this area is not detailed very well.
There may be, likely is, something I'm missing but you all have answered that question well. A LOT of time is spent searching the drawings to see how things are assembled and with what hardware. I wish that was more thoroughly called out in the kit. Mike and Keith have been great at getting questions answered but sometimes it takes some time to get an answer.

There is a drawing for the 24 galoon wing tank installation.. How far along are you? I have some simple dimensions that show where the drag and anti-drag wire holes go that save a lot of time and agrivation and I think I have quite a few pictures of the 24 gallon tank install as well.

[Bearhawk Builder]

I'm ready to install leading edges. False spar and hinges almost done, trammeled and wire tensioned. Tip bow done, flap and ailerons set and lined up, tank staps in. Keith sent me measurements for the drag wire holes and they're perfect. Struggling a little with riveting the flap hinge brackets to the false spar, hard to get in there.

[Steve Pierce]

Use screws and nuts on that one or do it with the skin removed. The drawing I refered to is mainly for modifying an existing wing. Still has some useful information though.


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[stewartb]

I thought about this thread today.... as I had to run a tap in all those holes to clean oit the poly-goo....

[kiwicubber]

Should the tank covers have a gasket or sealant around the edges? Can’t pick up anything mentioned in Univair or the L-21 Erection Manual.

[mike mcs repair]

Should the tank covers have a gasket or sealant around the edges? Can’t pick up anything mentioned in Univair or the L-21 Erection Manual.

No


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[mike mcs repair]

Should the tank covers have a gasket or sealant around the edges? Can’t pick up anything mentioned in Univair or the L-21 Erection Manual.

But there is a gasket like thing at filler neck


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[kiwicubber]

But there is a gasket like thing at filler neck


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Thanks Mike, have the filler neck one. 😀

cheers Bill

[Kodiakmack]

Saw this issue on Steve’s youtube video about common issues. Had a look at my -12 and the fairings run over the tank cover and all of the cover attach hardware are sheet metal screws into the installed nut plates ����*♂️ Is the -12 different in regard to arrangement and hardware?

[Steve Pierce]

Same on all the rag and tube Pipers I have worked on.

[Kodiakmack]

Thanks Steve. I figured as much. Looking at the rear nut plates from below it doesn’t appear they sit on the spar cap and would affect that as with the -18 is that correct? Unfortunately the larger sheet metal screws someone used have opened up the holes. Will keep working the problem but might have to stick with what was in there for now.

[Just call me Al]

Asked and answered really. The dimensions and size nut plates are in the Dakota Cub drawing. The rest is pure Piper. I would hate to build one of these without examples or pictures around to look at. Here are the tank covers installed with wing root fairings. Seen the fairings over the covers and screws but that is wrong and wears holes in the fairings.

Should these nut plates be floating or is that unnecessary? Do the nut plates need to be countersink (or flush) riveted?
Thanks for the info.
Al

[Kodiakmack]

Anybody have a part number for the gasket that’s supposed to go around the filler neck? There’s nothing on mine at all…

[sixmile]

make sure you put that tank cover on correctly. had one come off and wedged between the elevator and stabilizer could barely hold the stick set up for landing the nearest hill just on final and came out. had a passenger and a load of moose had to bend everything back to get out of there

[flybynite]

Anybody have a part number for the gasket that’s supposed to go around the filler neck? There’s nothing on mine at all…

The gasket that is used there is the same size as one that can be found at the big box store in the plumbing department. They are used between the base of a toilet and the water tank.

I'm not certain of the number of the similar aviation counterpart.

[Kodiakmack]

make sure you put that tank cover on correctly. had one come off and wedged between the elevator and stabilizer could barely hold the stick set up for landing the nearest hill just on final and came out. had a passenger and a load of moose had to bend everything back to get out of there

As in the entire tank cover?? Or just the filler neck gasket? Can’t imagine how you lost the whole tank cover. Glad you made it out of that one!

[Kodiakmack]

The gasket that is used there is the same size as one that can be found at the big box store in the plumbing department. They are used between the base of a toilet and the water tank.

I'm not certain of the number of the similar aviation counterpart.

man, I just sat down after coming back from Home Depot. I’ll check it out. Thx!

[sixmile]

whole cover just came out of annual and that was on the list to inspect and fix not repair

[Steve Pierce]

whole cover just came out of annual and that was on the list to inspect and fix not repair

That is a lot of screws to back out. How did the cover come off? Pictures?

[sixmile]

leading edge came loose wind got under that and peeled right off. when I fly through that area I can still see it in the bottom. happened years ago no pics

[Steve Pierce]

Ouch, I bet that made an erie sound.

[sixmile]

it was loud alright didn't know what happened at first looked back at the tail and there's the cover flopping around

[Kodiakmack]

it was loud alright didn't know what happened at first looked back at the tail and there's the cover flopping around

So I’m curious how to install the tank cover in a way that would cause this? Mine is attached via a piano hinge which has many sheet metal screws attaching it to the wing at the leading edge. Then the standard sheet metal screws down the sides and the 10/32’s at the trailing edge side.

[coxcub]

Quick question folks

Does the tank cover sit on the capstrip of ribs #1 and 4 or on the flanges - ie. be 'countersunk'?

The Dakota Cub leading and trailing edge covers are 'countersunk'.

Many thanks

Frank

[Steve Pierce]

Fuel tank cover should fit on the flanges. There ar no screws in that joggled recess area on the leading edges or the false spar to have to countersink.

[coxcub]

Thanks a lot Steve,

I thought that was the case but could not find a drawing which showed it. The old ones were both sitting on the capstrips.

Frank

[Steve Pierce]

You have to take the dimensions from the wing drawing and then take the tank cover measurement and figure it out. Throw some Univair ribs in there that have their mounting holes offset and it is a recipe for disaster.