I don't remember who tipped me off to this, and I couldn't find it on a forum search, so I started a thread about it for everyone else.
Someone told me that they had worn thru or almost thru their cowl because the aluminum engine baffling was rubbing on the cowl top. I just put it on my checklist for the next time I had the cowl off. This week I did, and sure enough on both the left and right sides, I have spots on the cowl top that are wearing in pretty harshly. If I had to guess I'd say I'm worn in maybe .030 or so.
The locations are, if I measure from the front outer corners of the cowl by the air inlet, about 9 or 9.5" in from the front corners of the cowl. The groves run maybe 1.5-2" long and then skip about 4" further back and then there is another spot that hits. With the baffle seals installed, it's tough to get a file on without wrecking the baffle seal, but I did manage to file it down in those areas slightly.
I put some gorilla tape over the spots and flew it for a couple quick flights, and yesterday I pulled the top cowl to check it again and it's still hitting a little. It's pretty good now in most locations with just one really heavy hitting area. I would suggest maybe when you do your baffles, you look at those areas and maybe about 8.5" to 15" back from the front corners of the cowl, I'd lower the baffle sides about 1/8". That should help eliminate the issue. You could go even further lower perhaps.
Someone told me that they had worn thru or almost thru their cowl because the aluminum engine baffling was rubbing on the cowl top. I just put it on my checklist for the next time I had the cowl off. This week I did, and sure enough on both the left and right sides, I have spots on the cowl top that are wearing in pretty harshly. If I had to guess I'd say I'm worn in maybe .030 or so.
The locations are, if I measure from the front outer corners of the cowl by the air inlet, about 9 or 9.5" in from the front corners of the cowl. The groves run maybe 1.5-2" long and then skip about 4" further back and then there is another spot that hits. With the baffle seals installed, it's tough to get a file on without wrecking the baffle seal, but I did manage to file it down in those areas slightly.
I put some gorilla tape over the spots and flew it for a couple quick flights, and yesterday I pulled the top cowl to check it again and it's still hitting a little. It's pretty good now in most locations with just one really heavy hitting area. I would suggest maybe when you do your baffles, you look at those areas and maybe about 8.5" to 15" back from the front corners of the cowl, I'd lower the baffle sides about 1/8". That should help eliminate the issue. You could go even further lower perhaps.