These skins were a pretty big job. I guess I'd say the size of the ouboard skins and the sheer number of holes is what makes it time consuming. I could manage moving around the big outboard skins myself, but going slow and thinking things out was a requirement.
First thing is edge debur all the skins, doublers and J-channel. Then put the wing walk doublers on. These add strength right next to the wing root to make an area of the wings you can walk on to get on/off the plane.
Be careful to orient the doublers correctly. I saw a guy online who had interference between the J-channel and the wing walk doubler because the doubler was flipped the wrong way top-to-bottom.
On one of the wings I ended up grinding a tiny amount from the ribs where it was interfering with the J-channel also.
The instructions give you an optional step "for aesthetics" to sand down the joint between the inboard and outboard skins into a taper. I gave it a shot with some 80 grit and an electric sander.
I put the edge of the skin on the edge of a 2x4 and sanded in full even strokes. I tried to put more pressure on the end of the skin so it would taper. I don't think I ended up taking off much, maybe 25% of the total thickness, but that was ok with me. If you really wanted to make that seam even, you'd probably need even more coarse sandpaper.
Commence assembly then match drilling. Oil that air drill up, its going to get some use!
Priming these big suckers is actually not that much work compared to the ribs. Just big flat surfaces. Scratch 'em up, shoot 'em green.
I always wait to dimple until after the skins are primed. The akzo epoxy is bulletproof so it sticks even during dimpling. Also, preparing the skins for priming with scotchbrite pads is much harder when there are dimples in the skin. It tears up the pads really fast.
It was difficult to get these monster skins dimpled myself, but between moving the tables around and some physical gymnastics, I made it happen.
Last you rivet. There are like 2000 of these suckers to shoot, and it took Dad and I about 14 hours over three days.
You do these in a different order than usual. Start in the middle of the skins, and rivet outwards. The double row that joins the inboard and outboard skins is last.
I did get a new tool to help us back rivet these skins. I know my buddy Mike J used a straight extended back rivet set to get his done. I presume he just nudged the bottom of the rib over to get a straight shot at the shop end of the top-side rivets. I tried out the double-offset set from Cleavland. It was pricy, like $50, but I think it worked really good and allowed me back-rivet quite a few more than would be doable with a straight set.
The thing you MUST do with this bar though is crank the air pressure. On my 3X gun I had it at 60 lbs to get the job done. I would hold the end near the rivet with one hand to keep it from spinning while running the trigger with the other hand.
Done. What a marathon!
Unfortunately I found out in the course of this chapter that a small number of folks I thought were close to me consider my project a joke. So be it I guess, to each his own. Doesn't phase me though, I know that this plane is going to be awesome and its going to haul my kids and me to some awesome adventures and memories. Maybe I even like people betting against me, its motivating as hell. So onto the leading edges I go!
First thing is edge debur all the skins, doublers and J-channel. Then put the wing walk doublers on. These add strength right next to the wing root to make an area of the wings you can walk on to get on/off the plane.
Be careful to orient the doublers correctly. I saw a guy online who had interference between the J-channel and the wing walk doubler because the doubler was flipped the wrong way top-to-bottom.
On one of the wings I ended up grinding a tiny amount from the ribs where it was interfering with the J-channel also.
The instructions give you an optional step "for aesthetics" to sand down the joint between the inboard and outboard skins into a taper. I gave it a shot with some 80 grit and an electric sander.
I put the edge of the skin on the edge of a 2x4 and sanded in full even strokes. I tried to put more pressure on the end of the skin so it would taper. I don't think I ended up taking off much, maybe 25% of the total thickness, but that was ok with me. If you really wanted to make that seam even, you'd probably need even more coarse sandpaper.
Commence assembly then match drilling. Oil that air drill up, its going to get some use!
Priming these big suckers is actually not that much work compared to the ribs. Just big flat surfaces. Scratch 'em up, shoot 'em green.
I always wait to dimple until after the skins are primed. The akzo epoxy is bulletproof so it sticks even during dimpling. Also, preparing the skins for priming with scotchbrite pads is much harder when there are dimples in the skin. It tears up the pads really fast.
It was difficult to get these monster skins dimpled myself, but between moving the tables around and some physical gymnastics, I made it happen.
Last you rivet. There are like 2000 of these suckers to shoot, and it took Dad and I about 14 hours over three days.
You do these in a different order than usual. Start in the middle of the skins, and rivet outwards. The double row that joins the inboard and outboard skins is last.
I did get a new tool to help us back rivet these skins. I know my buddy Mike J used a straight extended back rivet set to get his done. I presume he just nudged the bottom of the rib over to get a straight shot at the shop end of the top-side rivets. I tried out the double-offset set from Cleavland. It was pricy, like $50, but I think it worked really good and allowed me back-rivet quite a few more than would be doable with a straight set.
The thing you MUST do with this bar though is crank the air pressure. On my 3X gun I had it at 60 lbs to get the job done. I would hold the end near the rivet with one hand to keep it from spinning while running the trigger with the other hand.
Done. What a marathon!
Unfortunately I found out in the course of this chapter that a small number of folks I thought were close to me consider my project a joke. So be it I guess, to each his own. Doesn't phase me though, I know that this plane is going to be awesome and its going to haul my kids and me to some awesome adventures and memories. Maybe I even like people betting against me, its motivating as hell. So onto the leading edges I go!
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