Aft battery ground lug

[JDA_BTR]

I've got the fuse together but didn’t prep a ground lug hole for an aft battery in the left longeron which is nicely primed. I can remove primer but I’m wondering about trying to drill a big hole so close to the skin.

I saw a pic of a bar riveted to the longeron with the bolt hole in the bar. This seems structurally better.

Any thoughts on how many AD4 rivets would carry the start current adequately? Was thinking four or 5 on a short 1/8 bar having a ground bolt tab would get the job done without stripping primer with easier drilling to maintain edge distance on the longeron. Squeezing the rivets would make a good electrical connection in the holes. I wouldn’t prime the short bar.

Suggestions?

[Norman CYYJ]

I highly recommend that you clean the primer off of the aluminum.

[JDA_BTR]

Thanks. But I also don’t want to drill a big hole in the longeron.

[PaulvS]

I think Norman means to clean the paint off that part of the longeron where the un-primed bar is riveted on. That is what I would do and not rely on just the rivets to carry all those amps.

[JDA_BTR]

I agree. I’m still curious about the rivets and the current. And what the connecting bar might look like. I thought I saw a picture somewhere but can’t find it at the moment.

[Mikeyb]

https://vansairforce.net/community/a...8&d=1677667727

Courtesy of RYOUNG

[JDA_BTR]

Yes that’s it. How long do you think it is? 3 inches?

[JDA_BTR]

Was also thinking a nutplate to retain the bolt would be helpful.

[RYOUNG]

I patterned the ground lug from others I had seen surfing the web. It’s made from 1/8 inch aluminum and is 3 3/4 inch long and 5/8 inch wide with 7/8 inch wide bolt attachment lug. I used five AD4 rivets spaced approximately 3/4 inch to attach to the longeron. For corrosion protection, I dipped it in alodine. Hope this helps.

[JDA_BTR]

Excellent info thanks!