Engine Mount Bracket - Tight Fit

[TimSPEED]

Hi everyone.

so I have just made the jump from wing building to fuselage building - yay me - and of course you start with the firewall. All good, except when I go to trial fit the lower engine mount welded steel brackets, they clash with the aluminium stiffener - see photos below.





If I measure gap in stiffener it's only maybe 20 thou more than the stackup of parts, but the issue is the weld fillet in the corner, it runs higher than the gap. Obvious fix is to trim that lower edge of the stiffener so that it sits above the fillet. Maybe take 40 thou off.

Thoughts anyone?

(ADDED NOTES TO IMAGES)

 

[N804RV]

I'm not sure I understand what you're asking. But I do remember having to radius the edges of the weldments to get them to nest inside the flanges of the stiffeners. It didn't take that much as I recall. Getting all the riveting done in that area did increase my stress level for a day or so. I took a lot of time getting everything to fit just right and experimenting with different bucking bars to get on some of those shop heads.

 

[TimSPEED]

Thanks for reply. I added some notes to help, but this is how I think the side stiffener should be trimmed ...

 

[N804RV]

I seem to recall I did relieve that edge just slightly. A couple of passes on the 3M deburring wheel on my bench grinder was all it took, if I remember correctly.