Step 13.6 Oil cooler

Air cooled engines, like the one in my airplane, are actually cooled by more than just air blowing past the cylinder's cooling fins.  Internally, some of the heat is carried away by the engine oil.  This cooling is improved by the addition of  a radiator for the oil.  In this posting, I will illustrate the installation of my oil cooler.

The engine in my plane is a little larger that the standard engine for this aircraft and so I elected to go with a larger oil cooling radiator.  The trouble is that the larger radiator will not fit in the standard location which is hanging off of the baffles behind the rear left cylinder.  To overcome this problem, I will be relocating the cooler to the left side fire wall.

Whenever you veer off of the plans to make some sort of  modification to the stock aircraft you are skating on ever thinner ice as you go.  But this mod doesn't have any structural ramifications so I think I'm pretty safe here.

First up:  make some brackets to mount the cooler to the firewall.

The cooler's air source will be the higher pressure air above the engine on the left side and will be connected to the cooler by a flexible 4" hose.  An intake plenum is required to adapt the hose to the cooler and that will be constructed of fiberglass.  A male mold is fashioned using modeling clay and a roll of tape that is just the right size for the hose (after I peeled off about 5 ft of tape).

The mold is covered with about 4 - 6 layers of  9oz glass fabric and West Systems epoxy.

The plenum is then readied for painting 

And the brackets are installed.

And then the painted plenum is mated to the cooler and bracket.

Finally, with the addition of the hose, the cooler is complete.