The Cowl Shield is self-adhesive aluminium foil. The manual specifies the area of the cowl which should be covered, and it is slightly different for the EXP119 installation, as detailed in OP62-12.
Having said that, since we are installing the Vetterman Exhaust, I extended the foil rearwards to offer protection for the heat muffs.
The manual is scant on advice about how to tackle this job, advising to start on the outside, work inwards and the “the shield will conform to the shape of the cowl.”
Hmmm … you rapidly have to accept the fact that a flat sheet does not fit onto a complex curved surface without wrinkles!
Well, I did anyway. Others may have a magic method, but I couldn’t discover the trick.
I decided to do the job in sections … the exhaust pipe scallops, central area, then the two sides.
I used a stiff plastic squeegee as advised, and this helped to gradually work the foil onto the surface.
I attempted to “herd” the wrinkles into one spot, and then cut and overlap.
By doing this I was able to minimise the cut overlaps to about three per scallop.
The central area and the sides were easier.
It was very cold in the workshop, and I reckoned the self adhesive foil would behave better in a warmer environment, so I moved operations into the house : )
Eventually it was done!
Then I sealed all the edges with epoxy resin …
… including the joins and cut overlaps.
I marked the overlaps for sealing as they occured with a sharpie, since once pressed down they are hard to spot.
Finally I masked off the foil, since I wanted to paint the rest of the cowling white, as well as the upper cowling.
White will hopefully reduce heat absorption, and also make leaks etc easier to spot.
Just one job left on the upper cowling … to install the foam insert as per Page 47-30.
I may have to change the shape from the Vans template slightly due to the MT Prop Governor profile being slightly different to the Hartzell version.
I’m trying to find some suitable “closed cell” foam. The manual hints that suitable foam can be found in some avionics equipment packaging … but not in any of our boxes!
Lower cowling finally finished : )