Source: 2017 Q2 Beartracks, Mark Richardson
Well, in keeping with a lot of tasks on my scratchbuilt Bearhawk, I had been dreading the whole process of cutting the fuel tank filler neck holes in my wing skins. I was really worried that I would mess something up and cut the holes in the wrong spot (like that NEVER happens, right?) and wind up trashing some expensive sheets of aluminum. Well, turns out it was really easy and I did both holes in my left wing (I have an Aux tank) in a little over an hour and they both turned out perfect. I figured since I bored you in the last issue with some building tips, I might as well do it again since this actually worked out.

I was a little leery about using some of the methods I had read about, including the one about smearing some kind of liquid/putty/whatever on the rim of the filler neck and then pressing that against the inside of the skin. I didn’t think that would be very accurate.

This is what I did (your mileage may vary, batteries not included, objects in mirror are closer than they appear…)

1. I took a square of paper and drew a 2″ circle on it.

2. With spray contact cement, I attached the paper perfectly centered on the filler neck. I then put duct tape on paper facing up (towards the inside of the wing skin) along the side closest to the edge of the tank.

3. I then positioned the tank where it needed to be (vertically and horizontally) and then used a long wooden coffee stir stick to reach through a lightening hole and press the tape to the skin.

4. The tank was then removed. The duct tape easy overcame the stickiness of the contact cement, so the square paper template was now stuck EXACTLY where I needed to drill the hole. I drilled a #40 hole through the center so I could mark the hole on the top side of the skin.

5. Using a #40 drill, I worked my way around the hole and then used a Dremel tool and file bit to remove the waste in the center.

6. I used a spiral bit in an air die grinder to round out the hole and make it 2 1/4″ in diameter (1/8″ all the way around the hole). Why not go straight to 2 1/4″ at first? In case I buggered something up; you can’t put material back in :-)



That’s it. Quite easy actually. And nobody is more surprised than me …..