Definitely worth doing, Angier.  The the thermal radiation heat flux off the red hot exhaust pipes delivers a lot of energy to the inside of the cowl which, even painted white, looks "black" to infra red and so absorbs nearly all of it.  Using shiny reflective aluminum  to reflect it back to the engine which can tolerate elevated temperatures is better than the soaking it up with composite cowl and is a good idea.  I did the same using  reflective Zetex fabric (aluminized fiberglass furnace curtain  material) after seeing discoloration of exterior paint on some aircraft.  I think it is a much worse problem on the turbo airplanes because of much greater exhaust surface area radiating heat to everything that is line-of-sight from the hot surfaces.   Very nice job.  Looks good!   Fred Moreno       -------Original Message-------   I had some aluminum tape kicking around so I said to self, "what the heck, lets add to N4ZQ gross weight and move CG forward at the same time." :-) Was this a useless exercise or will there be some benefit as a heat shield? The sole objective was to help preserve the exterior paint surface. Angier Ames N4ZQ <IMG_03341.jpg> IMG_0334   <IMG_03352.jpg> IMG_0335   <IMG_03363.jpg> IMG_0336