Lower cowl attach do-over

Yep, I’m back at it. I didn’t do a lot – in fact the stuff I’ll write about here happened over the course of a couple days – but it’s something, right?

I’ve been thinking about this change for a while now. Going by the plans, the cowl attaches to the firewall using piano hinges. The lower cowl has four separate hinge pairs – one pair along the vertical sides, and another on the lower horizontal joint, on either side of the cooling ramp/exhaust exit. It seems that lots of builders have issues with those lower hinges cracking over time – sometimes over a pretty short period of time.

One common fix is to replace the cheap rolled hinges with pricier extruded material, which should hold up better. But after talking to some other builders, it sounds like an even better option is to get rid of the hinges in that spot, and just use screws for the cowl attach. Doing it this way means the hinges are replaced by a couple beefy alclad plates – and the .063” scrap I have lying around is perfect for this.

An additional benefit of this choice is that de-cowling with the engine hot should be less unpleasant. The pins for those hinges are removed on the inboard side – that is, where the exhaust is. It doesn’t take much imagination to envision some really fun burns out of that operation.

So anyway, that’s what I’ve been doing. I cut the new .063” mount plates to size, cleaned up the edges a bit, and match drilled them to the firewall joint. Now that they’re clecoed on, the lower cowl can go back in place, and I can get back to work sanding that cut edge.

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