Cowl vibration / chaffing particles or exhaust soot?

[George]

Flew through some rain showers for the first time  the other day. Tying the plane down I noticed the cowling was streaking with some sort of substance as you can see in the pics below. Anyone experienced this before?  Exhaust soot? Cowling vibration / chaffing between where the fiberglass cowling and aluminum meet?

Thanks

Hank

[skykrawler]

This is basically metal dust washing out of the fasteners.  Also, the cowl will chaff the aluminum edge to which it is fastened.  Usually there is anti friction tape to guard against that - but is can be difficult to eliminate all of it.   Easier to clean off before it dries completely.    Rain is hard on paint, too.

[FLYFST]

Has Corrosion-X been applied to the airplane?  If so, it may be the rain have pushed out some of the Corrosion-X film from inside the cowling.

[OR75]

How clean is the engine under the cowling? lots of oil leaking ? It gets washed at annual (like it is supposed to)?

[ArtVandelay]

I’ve seen this, although not to that degree.


Tom

[George]

No corrosion X and I removed the cowling 35 hours ago...clean cowling and not a lot of leaking oil. I have only owned the aircraft since late December. Headed to maintenance this weekend for tire change and new tailpipe. I will show pics to maintenance and ask about friction tape.

 

[carusoam]

+1 for fine metal dust that gets oxidized and loves to show up later... aluminum on aluminum rubbing is a dust factory...

For a finer more annoying example... look up smoking rivets.

+1 for CorrosionX being able to adsorb the same fine dust and bring it to the surface.... CX makes the rivets appear like smoking rivets... smoking rivets are more of a real problem... they are in the initial stages of becoming loose rivets...

The fine dust is pretty close to the molecular scale...

PP thoughts only, not a mechanic...

Finding a way to eliminate the rubbing is a good idea... chafe tape?

Best regards,

-a-

[BillC]

George,

Listen to GEE-BEE. I had the exact problem. It is caused by aluminum rubbing together producing the black dust. The silicone seal will fix your problem.

Edited February 17, 2019 by BillC

[jetdriven]

McMaster Carr UHMW anti chafe tape will fix the issue. 

[jaylw314]

I had the same rubbing problem, I used the Teflon tape from aircraft spruce:

https://www.aircraftspruce.com/catalog/cspages/chafetape05-11196.php

Fixed the problem on the upper cowl on the seam with the firewall.  I haven't applied it to the lower cowl seam because I keep forgetting, and the problem is less noticeable there anyway.

[OR75]

On 2/17/2019 at 12:13 PM, GEE-BEE said:

I have silicone seal

.032 thickness 

1” wide and 1-1/2 wide

This will act as a bumper and remove chafing

Advise your required length 

i will include clear cement 

 

GB

Not sure what your solution looks like . Silicon seal in the cowl overlap ?

[amillet]

On 2/17/2019 at 12:13 PM, GEE-BEE said:

I have silicone seal

.032 thickness 

1” wide and 1-1/2 wide

This will act as a bumper and remove chafing

Advise your required length 

i will include clear cement 

 

GB

Photos, website, prices, how to order?

[jetdriven]

use the high bond stuff on bare metal, such as the boot cowl. Use the other stuff for gear doors, upper flap skin, tail gap closeout panel, etc.

 

[bradp]

Guy is this what you’re talking about?