Fluting Question

[pilot28906]

I am fluting the HS ribs and am having some difficulty. I can get the punched holes in the flange lined up to a straight edge however the web does not lie exactly flat. Should the holes be lined up and the web lie flat or are the hole alignment only OK?

Thanks in advance,
John

[mikeasselin]

Hi there:

I just started on the HS and am using a straigh edge on the web to guide the fluting. There was an obvious bow prior to fluting.

I also found that there was quite a bit of squaring required on the ribs. Are you finding the same?

I did not pay too much attention to lining up the holes. When I preassembled prior to dimpling the holes lined up just fine.

Good Luck

[N674P]

Originally Posted by pilot28906

I am fluting the HS ribs and am having some difficulty. I can get the punched holes in the flange lined up to a straight edge however the web does not lie exactly flat. Should the holes be lined up and the web lie flat or are the hole alignment only OK?

Thanks in advance,
John

Yes, the holes should be lined up, the web lie flat and be 90* to the flange. It takes judicious use of the seamers, fluting pliers, and patience. It will probably take a while to get the hang of it (I'm looking forward to that time )
You may want to check out other posts on tips and tricks about HS nose ribs. Have Fun!

[BruceP]

I asked the same question to Van's when I started. The answer was "you're not building the Space Shuttle, don't worry if they don't lay perfectly flat". So I didn't and everything turned out well.

[Rick6a]

Originally Posted by BruceP

I asked the same question to Van's when I started. The answer was "you're not building the Space Shuttle, don't worry if they don't lay perfectly flat". So I didn't and everything turned out well.

What Van is really saying is "Don't overcomplicate it." Fluting ribs took me on average, all of one minute per rib. The end game here is to line up the holes in the rib and skin without "preloading" either part so you just need to flute as required. First, by using a hand seamer on the flange you can eyeball it to a reasonably square condition within a few degrees. By all means, use a squaring tool to verify a 90 degree angle if it doesn't seem quite right. Then comes the easy part.... I just laid a rib down on a smooth surface, noted the location of the bow and fluted key locations on the rib until it flattened itself out. You can do this without actually touching the rib with your hands. A trick I use is to generate a few flutes on the upper surface, then rotate the part around and flute a few locations on the lower surface. This seems to help flatten the rib evenly. The ribs are all different. Some ribs took lots of flutes to straighten, others just a few. After a while, you sort of develop a feel for how much force to apply to the fluting pliers to generate a shallow flute or a deep flute as required. Note how few flutes were really needed to straighten the rib in the bottom right photo. If it takes more than 2 or 3 minutes to flute any one rib, adopting a more efficient technique might save yourself considerable and needless tedium.

[Jamie]

Here are some general things I do when fluting.

• Deburr the flanges before you flute them. This way you can more easily run a scotch-brite wheel down them. It's a little harder to do it with the flutes in there.
• You only need to flute something if it's curved (i.e. wing/emp ribs and fuse bulkheads). If it's a straight bend it doesn't get fluted (ex: the aft flanges of the emp nose ribs).
• The tighter the radius of the turn, the more 'flutes' are required in that area. The shallower the turn, the shallower the 'flutes'.
• If you're careful you can flute and bend the flanges to 90 degrees with the fluting pliers w/ one movement (i.e. squeeze the flute...then rotate inward to get the angle to 90 degrees). I did this for most of my ribs and only used the hand seamer for minor adjustments.

Oh yeah...this is something you can bring inside and do while watching TV with your significant other. :-)

[pilot28906]

Thanks for the information. I have the holes straight, but I think I need to do a little more work in trying to get the web to lie flat.

John

[Mel]

Hey,
If you guys need fluting experience, I have 42 wing ribs (.016) that need de-burring and fluting. Come on over.

[gpiney]

I went through the same thing last summer. I discovered a few things which I posted here:

http://www.vansairforce.com/communit...hlight=fluting


First and formost is to finish the edges and square the flanges to the web. The most important issue is that the prepunched holes are dead straight. Sometimes a rib with the holes dead on will not lie exactly flat. But it will be real close.

[johnp]

agree with the already stated "edge finish and square up before fluting" advice. one thing i found useful after that was to thread some black fishing line through the first and last hole of each rib flange, held in place with spring clamps. then i could easily see if the holes lined up as i fluted.

ymmv,

john