chafing on cowl

GeorgeC

GeorgeC

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GeorgeC
How does one address "hot spots" like these where vibrations are causing the sheet metal to wear?
cowl.jpg
 
For areas such as where baffling rubs on the aluminum cowl, the Reflectix tape at HD appears to be identical to the similar tape from Spruce.

This set has been on for several years and is now in need of replacement

IMG_7829.jpeg
 
Granger had clear tape identical to C-152 application similar to OP.
 
I used the anti-chafe tape and pliobond. Clean up the metal, cut the tape to length, add the pliobond and then the tape, press it down and clean up the excess. If you have hinges, screws, holes, etc, then it’s a bit of a challenge to get a hole in the tape for those to fit, so take your time on that part. I ended up cutting the tape smaller and going around the holes. I bought a hole punch and it wouldn’t put a hole in the tape to try to accommodate a screw hole from cowling to fuselage. But it was one of the easier projects I did.
 
Correct the shape(s). Address the problem, not the symptom.
 
Unrelated, but curious, what are those cowling door/hatches called? I know the Grumman's, and certain models of Bonanza have them. They are way more handy than a small oil door.
 
The OP's airplane very likely had the fabric anti-chafe tape when it left the factory. The stuff gets worn and oil-soaked and the adhesive lets go, so owners or mechanics pull it all off without realizing why it was there in the first place, and the metal gets chafing and the damage can get bad enough that major metalwork is necessary.

That O-200 also needs new Lord mounts (or their equivalent). Look at the sag in the mount:

1751307868409.png

At that point the steel tube on the bolt is hammering on the inside of the engine mount lug. Not good. In fact, the mounting bolt's tube on the mount itself appears to be well off-axis with the engine's lug. The bolt is tilted downward.

Is that hose nipple on the baffle blocked off, or is much cooling air differential pressure escaping through it?

What airframe is that?
 
Dan Thomas said:
That O-200 also needs new Lord mounts (or their equivalent).
Click to expand...
Yeesh. Thanks. I'd ASSumed those mounts were changed at teardown, 5 years ago...
Dan Thomas said:
Is that hose nipple on the baffle blocked off, or is much cooling air differential pressure escaping through it?
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It is now blocked off; see
www.pilotsofamerica.com/community/threads/carbed-cht-spread-over-time.140307/post-3327651
A couple of rounds of baffle improvements later, #2 still runs a bit warmer than the rest, but it's much better than it was. A little more baffling still needs to be replaced. Maybe this fall; working on the ramp in summer is for the birds.
Dan Thomas said:
What airframe is that?
Click to expand...
C140A.
 
Yup you got to be brave to post your stuff on POA.
I have learned a lot posting pictures of what I was working on thanks to friends like Dan, Bell2206, magman and many others. Thanks
 
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So, does the anti-chafe tape go on the door side, the airplane side, or both?
 
kep5niner said:
Airplane side, after copious amounts of prep to ensure good adhesion.
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I have seen it on the door, too. Either way works. But the prep, as you say, is critical. No decent prep and the stuff will peel off and you'll be doing it again, with new strip and new cement and proper cleaning.

Oil leaks that are sending oil onto the firewall or door should get fixed. Oil soaking into the chafe strip will break the cement's grip on it.
 
GeorgeC said:
Yeesh. Thanks. I'd ASSumed those mounts were changed at teardown, 5 years ago...



C140A.
Click to expand...
Assuming that's a C-90 in your C140A, that sag could easily have occurred over the ensuing 5 years. They get replaced fairly often in my experience - not a terribly hard job.
 
The door had a built-in alignment guide:
tape.jpg
 
I've lined the inside of my cowling where the soft baffles make contact with aluminum foil duct tape. See photo in post #4.
 
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