Brief Description: Drilled upper cowl to firewall hinge
I continued work on the upper cowl today. After convincing myself I had a good fit I marked and drilled the rivets along the firewall hinge. I could not find a spacing requirement in the plans so I used the pattern on the upper skin flange, overkill but I did it anyways. I did not include the shim when I drilled the cowl to the hinge; basically I did that in the next step. I clamped the shim onto the hinge exactly 1/16” from the skin, this is the same distance needed for a paint seam, my idea is I now have something to sand the cowl to which will give me a nice line with no waves.
I match drilled the shim to the hinge from the underside using my angle drill, there were 4 holes I could not reach so after deburr I clecoed on the cowl with the shim and match drilled these holes from the top. Turned out nice! Now I need to tackle the lower cowl.
NOTE. In my effort to have the spinner slightly higher than the cowl I failed to realize how much the cowl being trimmed to the firewall would move the front up some (aft was resting on the skin not hinge which is lower). I now have a nice fit cowl to spinner but if I get any sag then I will need to add washers to the lower engine mounts. My engine has been hung for a year so my hope is I will see little to no sag but time will tell.
Gap between shim and upper skin is paint gap needed
This fit is what I want but will not allow for sag!
