Tank end rib hole - how big?

BSwayze · Post by **BSwayze** » Tue Oct 23, 2007 3:27 am

I'm at that point in my tank construction where I need to break out the fly-cutter for the first time and cut the big holes in the inboard end ribs for the reinforcing ring and the access cover plate.

I've studied the plans and drawing 16A over and over and I can't find anything that indicates how big this cutout should be. Should I just set the flycutter to cut a hole the same size as the inner diameter of the reinforcing ring? Section C-C' and section B-B' on drawing 16A seem to indicate that this cutout hole is a bit smaller in diameter than the inner diameter of the reinforcing ring, but no radius or diameter is given. Am I missing something? Is it that critical?

Any input would be greatly appreciated. Thanks!

Bruce Swayze

RVNewsletter · Post by **RVNewsletter** » Tue Oct 23, 2007 7:41 am

Bottom line to your question. Yes. The inside diameter of the reinforcement ring.

Note on the plans the distance between flat flanged line on the rib and the flat edge of the access panel/reinforcement plate. Align at that point.

You want to be sure to have enough edge distance between the holes that are going to be drilled to hold the plate in place and the holeyou're about to cut.

Post by **bullojm1** » Tue Oct 23, 2007 9:10 am

I think I did mine the diameter of the reinforcement ring in the rib. You want to make sure that when the reinforcement ring is installed, it is flush with the web of the rib.

Here is a pic of my rib with the fly cutter:
http://rvplane.com/showthumb.php?picname=IMG_6608.JPG

And my web long entry for the task:
http://rvplane.com/?categoryid=3&dayid=211

captain_john · Post by **captain_john** » Tue Oct 23, 2007 9:01 pm

I don't own a flycutter. I used my holesaw. It worked perfectly and I can still count to 10!

Holesaws are expensive, but I already have a good set.

I like them better than flycutters.

CJ

smittysrv · Post by **smittysrv** » Tue Oct 23, 2007 9:39 pm

I used my Unibit in my drill press and smoothed everything off with my belt sander.

http://smittysrv.com/more_stuff.asp?ID=412

BSwayze · Post by **BSwayze** » Wed Oct 24, 2007 12:33 pm

[quote="smittysrv"]I used my Unibit in my drill press and smoothed everything off with my belt sander.

How did you get a belt from a belt sander inside the hole?

Post by **Spike** » Wed Oct 24, 2007 1:02 pm

This is a picture from his site. Its not the type of belt sander you might have been thinking of:

Spike

Post by **bullojm1** » Wed Oct 24, 2007 1:45 pm

Looks like a bench sander, similar to the following:

I picked up a used one of these and it has been a great tool to have. Whenever you need to eat some aluminum in a hurry, it does a great job.

BSwayze · Post by **BSwayze** » Fri Oct 26, 2007 8:42 am

Looks like a bench sander, similar to the following:

I picked up a used one of these and it has been a great tool to have. Whenever you need to eat some aluminum in a hurry, it does a great job.

Thanks, Mike! I have a similar Craftsman bench sander, but it has an 8" disk and the belt is 4" wide. By the way, I really enjoyed finding your web site. Great job!

Post by **bullojm1** » Fri Oct 26, 2007 9:16 am

BSwayze wrote: Thanks, Mike! I have a similar Craftsman bench sander, but it has an 8" disk and the belt is 4" wide. By the way, I really enjoyed finding your web site. Great job!

Bruce-

Thanks for the kind words on my site. I am just glad at least one person goes to it! Good luck on your tanks!

BSwayze · Post by **BSwayze** » Wed Dec 12, 2007 4:52 am

Hey Guys...

Great news. The balloon held full for over 3 days, so I can officially declare one tank finished, with NO LEAKS! Yippee! One down, one to go.

Special thanks to Mike B. for emailing me offlist and answering some questions. Thanks, Mike!

I'd post a picture here if I could figure out how.

Bruce

UPDATE: 2-7-2008
Now that I had some help figuring out how to post pics, here's a shot of my tank and the balloon, still full after 3 days!

Post by **Spike** » Wed Dec 12, 2007 8:49 am

Congrats!!!

Post by **bullojm1** » Wed Dec 12, 2007 10:22 am

Bruce-

So far in the build there hasn't been a better feeling then LEAK FREE TANKS! I suppose maybe the first engine start or first flight *might* beat it

I am glad I could help out!

tmbg · Post by **tmbg** » Wed Dec 12, 2007 10:23 am

I'm right behind ya! I have to mix one little batch of proseal to catch the corners of the end ribs up by the baffle and fillet the baffle itself, and then I can pressure test the sucker!

BSwayze · Post by **BSwayze** » Fri Dec 14, 2007 5:08 am

Ian,

I looked at your web site and all your pictures. I couldn't help but notice that you don't seem to have the trailing edge of the wing secured in your wing stand. Did you hang plumb bobs and check for twist? Are you concerned about that before riveting the skins on? Or am I missing something? Just thought I'd mention it and check with you. Good luck on your tank!

Bruce

tmbg · Post by **tmbg** » Fri Dec 14, 2007 10:37 am

from what I've read and talked with other folks about, that's a lot less of an issue with the pre-punched kits than it was with the older kits.... these days you don't need a 'jig' so much as a 'stand'.

BSwayze · Post by **BSwayze** » Mon Dec 17, 2007 7:47 pm

Ian,
That's great! I probably went to a lot more trouble than I needed to then. Let us all know how it turns out. Did you get your tank finished?

jim_geo · Post by **jim_geo** » Mon Dec 17, 2007 8:35 pm

This pre-punched stuff is definetly bench top buildable.

tmbg · Post by **tmbg** » Tue Dec 18, 2007 12:07 pm

my tank is done, but I'm waiting for Dan to come over and safety that flop tube for me so I can replace the inspection cover and mount it on the wing!

allbee · Post by **allbee** » Fri Dec 21, 2007 12:34 pm

bullojm1 wrote:Bruce-

So far in the build there hasn't been a better feeling then LEAK FREE TANKS! I suppose maybe the first engine start or first flight *might* beat it I am glad I could help out!

the tanks are nothing, wait until you do the canopy

RivetBangers.com

Tank end rib hole - how big?

Tank end rib hole - how big?

No leaks!!!

Ian - Check for twist?