Joggles on the ribs

[way_up_north]

looking at the plans there are joggles at the top and bottom of the centre rib at the front....but none I see on any of the other ribs that have spars worked into them...so it's only joggles at the front of main rib top/bottom...no joggle at the back of the main rib for the rear spar?....etc...

[marcusofcotton]

The joggle at the front end of the center ribs is to accommodate the main spar flange thickness and has been considered optional.

[fairchild]

Would you make that joggle after the rib was finished or during the forming process..... ? and how would you do it since the bend line is about where the joggle is ?
Would I hand cut a depression in my form block at the front corner ?

Seems like a pair of forming blocks mounted in a big pair of vice grips might work ? Since the offset would be pressed through the bend radius--and that
zone is all ready work hardened--- what would the shape of the first 1+1/4 of the bend line look like with a radius AND an offset ? Doesn't seem like you
could do a jog without causing a too-tight bend radius there somewhere.....

Has anyone done it to show us what it looks like ? and share a picture ?

[marcusofcotton]

I believe some have incorporated it into the form block and others have improvised tools. Probably the most common tool is a simple slotted piece of steel that is used to bend it in. I don't have any pictures but I'm sure some searching will prove fruitful.

[way_up_north]

Try giving this a watch...thou I think I’m just going to adjust the height of the form block

after watching this you’ll be the joggle king

https://youtu.be/xdFYm5OHKGc

[fairchild]

That tool looks sweet for flat joggles but maybe not for a curved or compound curved material. Since the joggle is only .032 you couldn't build it like that.
Might be able to take some 1/4 or 5/16 steel blocks and weld them together on one end (maybe with some stiffeners) and adjust the center offset to .032- or .040 .
The 2 plates might have to be bent to follow the curves of the material. or maybe even just ground. I will be trying that in the next couple of weeks-- so if I get something
that works easy I will post a pic of it.

Tim

[Weldingiron]

Since the joggles are considered optional and only .032 at most, what are the potential downsides of not forming them? Would it be a slight cosmetic issue or actually impact the flight characteristics?

[Chris In Milwaukee]

Purely cosmetic, and barely noticeable.