F-623 Baggage Rib

[macrafic]

The instructions indicate to flute the F-623 ribs (baggage floor ribs) to fit the skin (I think this is the F-776 skin). I've done a lot of fluting up to this point and understand the concept (I've built the wings and empennage), but don't see how fluting could help in this situation. The rib lies with its web against the skin and its flanges up (at 90 degrees to the skin). I don't understand how fluting could help do anything in this position. I know I'm missing something here. Can anyone spot it?

 

[bullojm1]

I didn't flute mine either.

 

[Jamie]

The bend on the bottom flanges of those ribs is not a straight bend...there is a slight curve. In other words, when you have all of this stuff clecoed together you'll see that the bottom skin has a slight curve. The fluting process is simply to align the rib with the holes in the skin. If you just cleco those on, you'll see that the holes don't line up so well. That's the purpose of fluting. I believe the top flanges on that rib are a straight bend, so there is no need to flute the top flanges, only the bottom. Since the curvature of the bottom skin is very slight, very little fluting (if any) is required.

 

[IowaRV9Dreamer]

fluting the baggage rib

Just did this last night (after figuring out to cut both ends off the rib).... If found that if you put a straightedge across the rib web/flange intersection, one of my 2 ribs was somewhat bowed. By very slightly fluting the outer rear flange, it straightened up. It was very minor.

Good Luck,