Fwd Fuse Gusset Fit

[skelrad]

My F-695 Fwd Fuse Gusset doesn't seem to fit all that well. On the left side, my longeron twist looks to be really close to what it's supposed to be (sits snugly into the angle of the upper engine mount bracket), but because of how the top firewall stiffener fits against the longeron, the gusset doesn't nest against the stiffener where the stiffener and longeron meet. Am I good to bend the gusset to match, or do I need to address something else so I don't back myself into a corner with another part down the road?

The left side isn't horrible, but on the right side, it looks like my longeron is under twisted a bit (maybe between 1/32-1/16" gap between it and the engine mount bracket - although with a little pressure that gap closes up pretty well), causing the gusset to have a bigger gap. I'm trying to figure out how I deal with that given everything that is riveted together at this point.

[idubrov]

I slightly bent the gusset to fit the key points (where the rivets are) as good as I could.

I think, I also had a small gap between the longeron and the engine mount -- it all went away once I riveted everything. I haven't fitted nor riveted the top skin, however, so I might still get into trouble in the future.

Also, among all the edge distances to watch for (edge of the longeron, the inner / outer edges of the engine mount tabs), one non-obvious was the spacing for the shop head of the 4th aft rivet (4th counting from the aft).

On my first try, I located all 14 longitudinal rivets equispaced and that 4th rivet hole got located exactly at the edge of the engine mount "tab" under the longeron -- wouldn't be possible to buck the rivet.

(I'm building RV-7, but I think the fuselage is very similar to RV-9.)

[nohoflyer]

You want the gusset to be even with the edge of the longeron and firewall. Bend as needed. Make sure you drill the holes along the longeron side iaw the plans. The rivets need to have edge distance on all three layers on the longeron side.

Along the firewall side is where I used a few of my cherry-maxes due to bucking bar accessibility.

I just finished this section awhile ago and there are no future gotchas.

[GeoffP]

I just checked my photos from when I riveted these parts on about a year ago. The fit was just fine, across both the main longerons and the firewall angle, but it looks like I just increased the bend in F-695 a little towards the firewall end.

[Girraf]

Mine didn't fit very well. I had to increase the bend angles to get it to sit nicely. Thinking back, I spent a fair amount of time on these between laying out the rivet patterns, figuring out that the fwd edge of the doesn't wind up parallel to the firewall when its also parallel to the longeron, and adjusting the bend angles.

Karetaker aero on youtube had a nice detailed discussion about this specific task.

[nohoflyer]

Btw my right side did not sit well either. Big gap between the longeron the weldement. I added a fat shim.