I’ve been having some GPS problems that I suspect might be related to the box getting hot. The first step was to install a vent in the boot cowl up above the stack, but that didn’t seem to help. After considering options like fans and extra exterior vents like Cessna did for a while, the best option seemed to be tapping off of the air that is already coming into the cabin. The easiest way I could think to do this was a tee fitting with 2-inch flanges on the through ends and and 3/4-inch flanges on the short end. Somebody may make these, but I couldn’t find them. Thankfully, my friend Alan is a good welder of seemingly anything weldable. I brought him a 2″ diameter tube and a 3/4″ diameter tube:
And he fixed it right up.
After his welding I trimmed all of the flanges to about 1″ long, cleaned up the edges, and drilled the hole in the side of the 2″ diameter tube. I figured drilling this hole after the fact would help with the thermodynamics during welding, and make it so that we didn’t have to try and hit a predetermined spot with accuracy. I started with a 3/8″ diameter hole, which could be enlarged for more flow.
Then I removed the old scat hose that connected eyeball the the NACA scoop, and replaced it with the new tee in the middle.
A foot-long piece of 3/4 scat connects the tee to the avionics, with support from wire ties.