Any tips for cutting big holes in wing skins?

[Spaceman]

What's up guys, I'm getting close to closing up my first wing but I have a couple of slightly intimidating things to do first, namely cutting the hole on the underside of the forward skin for the pitot tube, and cutting a big hole in the leading edge for a Duckworks landing light.

The pitot tube installation calls for a 4" round hole, to match a 5" diameter inspection plate which the pitot tube mounts through (I think this is a new method for the B model...). The landing light just takes a big rectangle.

Anyone have any tips or tricks on cutting these big holes nicely? Would it be easier to cut the landing light hole with the forward skin installed or not? I'm not sure if the tension the skin is under when installed would affect anything. Any particular tools recommended? I kinda figured just drill a big unibit hole and cut the rest with snips...

Maybe I'm over thinking it but I have a lot of dollars and hours invested in this leading edge already so I don't want to mess it up!

[Corby202]

I cut the leading edge holes for the landing lights after the wings were complete using a hand held Nibbler. Took a while but you cant really mess up taking such a small amount of metal out at a time. A file to finish off.

[NWade]

What's up guys, I'm getting close to closing up my first wing but I have a couple of slightly intimidating things to do first, namely cutting the hole on the underside of the forward skin for the pitot tube, and cutting a big hole in the leading edge for a Duckworks landing light.

A unibit and then a set of snips, a nibbler, and/or a dremel is the way I'd go (and is essentially how I did it). You can use small files and scotchbrite pads to hand-finish the edges of the holes and make them really good-looking and precise. Note that the dremel is the fastest way to cut between some unibit holes, but also the easiest way to mess up the skin! :-P

I'd really recommend doing this with the wing skins cleco'ed in-place, so that they're in their final shape and you don't have to worry about any flex or curvature of the parts changing the shape of the hole once you attach/rivet it.

Measure thrice, mark twice, cut once, and then sneak up on the final dimensions with hand tools. You've got this thing!

--Noel
P.S. Here are some photos of my Duckworks Landing light hole:
https://photos.google.com/share/AF1QipP ... VnRmJsWHpR

https://photos.google.com/share/AF1QipP ... VnRmJsWHpR

https://photos.google.com/share/AF1QipP ... VnRmJsWHpR

[edclee]

What's up guys, I'm getting close to closing up my first wing but I have a couple of slightly intimidating things to do first, namely cutting the hole on the underside of the forward skin for the pitot tube, and cutting a big hole in the leading edge for a Duckworks landing light.

A unibit and then a set of snips, a nibbler, and/or a dremel is the way I'd go (and is essentially how I did it). You can use small files and scotchbrite pads to hand-finish the edges of the holes and make them really good-looking and precise. Note that the dremel is the fastest way to cut between some unibit holes, but also the easiest way to mess up the skin! :-P

I'd really recommend doing this with the wing skins cleco'ed in-place, so that they're in their final shape and you don't have to worry about any flex or curvature of the parts changing the shape of the hole once you attach/rivet it.

Measure thrice, mark twice, cut once, and then sneak up on the final dimensions with hand tools. You've got this thing!

--Noel
P.S. Here are some photos of my Duckworks Landing light hole:
https://photos.google.com/share/AF1QipP ... VnRmJsWHpR

https://photos.google.com/share/AF1QipP ... VnRmJsWHpR

https://photos.google.com/share/AF1QipP ... VnRmJsWHpR

The best way is to make a template and tape it in place. Maybe with polycarbonate then heat it and bend it over the leading edge, then cut the hole with a small router you can buy cheap from harbor freight with a carbide end mill. Set the depth so the smooth shank of the end mill rides on the inner surface of the template and follow it around. The is the best way to cut round holes or odd shapes in the skin. Also great for cutting slots for trim tab rods etc.
Ed
Sonex 1212



Sent from my iPhone using Tapatalk

[Bryan Cotton]

viewtopic.php?f=39&t=578&start=600

Looks like I drilled holes in the corners, hand nibbled around the radius, and I remember using the 4" grinder with a metal cutting wheel to do the straight sections.

[Spaceman]

Nice! Thanks for the tips guys. I just snagged a hand nibbler on amazon prime for like $13... not bad. More tools for the basement.

I think what I'll do is finalize everything in the aft part of the wing and just rivet the upper and lower skins on. Then I'll put the wing back flat on the table and do this stuff on the forward part. Right now I have the wing sitting on stands, leading edge down, which is great for getting at both sides but obviously I can't work on the forward skin at all like that.



Once I make these cutouts I think all I have left is running the wires and pitot/static lines, then riveting the forward skin, then this thing will be done!

[Sonex1243]

I cut the hole for my pitot tube with the leading edge skin cleco'd in place. Used the biggest unibit I had and nibbled / filed the hole. I ran all the pitot lines, installed the duckworks light and wiring as well before riveting shut. I didn't actually open up the leading edge for the light until well after both wings were built. The duckworks template was spot on, I drilled a line of small holes along each corner and used a die grinder with cutoff wheel for the straight lines and cleaned it all up with files / scotch brite.

[Bryan Cotton]

You could save the pitot hole and make a nifty tail mounted pitot a la Kip.

Not that I am being subversive here or anything.

[Spaceman]

I saw that and it's pretty cool! However I plan on putting an LRI in the same spot on the other wing, so for the sake of symmetry I'll just stick to the plan!