Are skins necessary here?

RV-10, section 29-13, step #6. This is where you drill the forward side skins to the longerons. Immediately after match drilling the longerons to the side skins you match drill the pre-drilled holes in the firewall gusset up from the bottom and into the longeron. This is very similar to a previous step which I messed up royally (discussed recently here).

How on earth do you do this? There's no access and you can't even see the pre-drilled holes. The skins are supposed to stay on until page 29-14, step #1 (several steps away). Maybe they're intended to help keep things aligned. I don't know. I'm just not seeing how any of the following steps can be done with these skins cleco'ed in place. What am I missing here? I'm really, really trying to avoid another 8 hour do-over.

I'm thinking drill the longerons to the skins, then clamp real tight to the gusset (as the plans say) and just remove the skins now rather than later. Comments?

Joe,
I am not seeing the issue with access. Which specific step are you referring.

Patrick Kelly did what I think I did - just used a longer bit. you can get it into the gusset hole by feel/with mirror, and bend the bit as it goes to keep the hole fairly straight. I didn't see and drill chuck rubs on the skins below (like in some other places). I also grabbed the air drill with a regular length bit and there seems to be room to drill that way too. To answer your question, though, once it's clamped I don't think loosening up the skin down below to improve access is going to move things. You can outline it with a sharpie and check before commencing to drill.

==dave==

Bill.Peyton said:

Joe,
I am not seeing the issue with access. Which specific step are you referring.

Click to expand...

Starting in the 2nd half of step #6, page 29-13, where you match the longeron to the gusset.

Here's a picture. The right side of the pic is the firewall. The left side is the skin. You can see the longeron resting on the gusset. The holes are pre-drilled in the gusset and you drill into the longeron from below. How can I get a drill in there? How can I even see what I'm doing if I could get a drill in there? Yes, I can get a 90 degree drill and a mirror, but that's how I messed it all up in that previous step I mentioned.

Joe,
I assume you have the 6" and 12" bits, what type of air drill are you using? You should be able to get the drill in there, especially using a long bit and holding it in you hand to allow it to bend

Bill.Peyton said:

Joe,
I assume you have the 6" and 12" bits

Click to expand...

I do. But still, you can't see what you're doing and going by feel is a recipe for disaster (for me, at least) - maybe that's the best way. .... But then there's the next few steps which seem completely impossible with the skins in place.

Joe, all you need are a couple of holes cleco'd, then you can remove the pieces and finish the remaining holes. Use a mirror to see what you are doing. Maybe a helper would make it easier.

skins?

So let me get back to the skins part of the question. Does anyone know of a reason why NOT to remove the skins now (29-13, step#6)? After the longerons are matched to the skins there doesn't appear to be any reason to leave them on (assuming I clamp the longeron to the gusset real good), despite the fact that the plans don't have you remove them until 29-14, step #1. Am I missing something?

I used as Bill mentioned...a very small air drill, a sharp lubricated 12" bit, eyeballed it perpendicular to pieces, manually kept bend in drill bit and drilled away. I used masking tape anywhere a drill chuck may touch. I followed the plans and fortunately only had some scrap brake/fuel tubing in the end. There is a knack to it. Wish I was closer to help you.

Template

I'm not here yet stiLl on section 28. Do you think you could make a template on a scrap then transfer to the longeron?
Just thinking out loud.

Joe, you also might try a strap duplicator and drill from the top

solved

Bill.Peyton said:

Joe, you also might try a strap duplicator and drill from the top

Click to expand...

I thought about this and was about to order them when I realized the thickness is probably too large for the strap duplicators. They're made for skins best I can tell. I don't know for sure though. They might work in this case. It's moot now.

I got it solved and am very happy with the results. Here's what I did. I clamped the longerons to the gusset according to the plans. I match drilled the longerons to the skins according to plans. Then I skipped drilling the gusset and did steps 7 through 10. Then I marked the gussets and longerons where they were clamped together to make sure the don;t move and I removed the skins. After verifying that nothing moved, I simply drilled up from the bottom with a long bit. Trivial at that point.

Thanks for all the suggestions.

Joe, if I remember correctly that's exactly what I did at that point in the build. As a side note: from the fuselage on I just used the instructions as a guide line and checklist. The order of things are not perfect and I often build using a different order than the plans. I read through an entire section first to understand the construction and think through all of the steps. I often rearrange the steps or add notes to be sure to complete something prior to the next step.

Best of luck,