Fitting the F-684 gussets...

Thermos · Post by **Thermos** » Sat Mar 24, 2012 1:06 pm

Hi all,

I'm braining out how to fit the F-684 gussets to the lower firewall weldments and aux longerons. I fabbed the first one according to plan, double-checked my measurements and cuts, and am finding out that the cutouts and bend lines aren't lining up the way they drawings indicate. Here's a pic...

I know, I know...those of you who've already done this are laughing and thinking "he expected them to fit!"

So...it seems like the lower (or upper in this pic) bend line and cutout should have been a lot further down on the gusset...as bent and cut per plans, there's no way it will fit without adding another bend in the circled area, and I'll probably have edge distance issues as well - so I'm going to order another part from Vans and go off-plans as necessary on the bend lines and cutout.

Thoughts? Did anyone else have problems in this area? What did you do to make these parts fit?

Thanks,

Dave

Lorin Dueck · Post by **Lorin Dueck** » Sat Mar 24, 2012 3:12 pm

Dave -

That gusset gets a notch cut in it (and the corner cut off).
See drawing 23 (for a 9 / 9A).

Good luck! Lorin

cjensen · Post by **cjensen** » Sun Mar 25, 2012 7:48 am

Looks like you already have the notch cut...but they do get bent a little to fit. You can see the light reflection in this pick on how they bend to fit.

They fit nicely after that.

Thermos · Post by **Thermos** » Mon Mar 26, 2012 9:46 am

Thanks guys. Chad, the pics help a lot!

I bent up a test piece last night after looking at the pics and also discussing the problem with Captain John. He ended up putting a joggle on the gusset's lower edge to get it over the weldment, and I think I'm going to do the same thing. Just one bend won't do it on that part of the gusset.

The plans also indicate that the lower edge of the gusset is supposed to be even with the lower edge of the aux longeron...I don't think that's going to work with the relief cutout as shown on the plans. Chad, it looks like you might have moved the gusset up (or down in the pic) to get the cutout to work?

Dave

Lorin Dueck · Post by **Lorin Dueck** » Mon Mar 26, 2012 5:01 pm

Dave -

Sorry - I should have looked at your pics closer before I replied.
I see you have the notches cut out.

Also, it's probably obvious - but don't forget to install the nut plates before you rivet the gussets in place.

Lorin

cjensen · Post by **cjensen** » Wed Mar 28, 2012 8:50 pm

Thermos wrote:Chad, it looks like you might have moved the gusset up (or down in the pic) to get the cutout to work?

Dave

Sure did Dave...doesn't matter the precise location, just make it fit, but make sure you have appropriate overlap of the gusset edges and longerons for strength.