Chapter 23: Engine Cooling Baffles
Step 7: Engine Cooling Baffles
(Updated 4/3/2012)
A More Effective, Updraft Cooling Concept
The Problem:
It’s my opinion that the Cozy IV cowl ingests a lot of air that doesn’t do real work. Air swirls and stagnates in the upper firewall and in the wing roots. Its volume and pressure contribute nothing to flowing air through the cylinder fins. Worse yet, a surprising amount of air leaks out through the gaps between wing roots and the center spar, and through gaps where the cowls are attached to wing roots.
A New Concept:
For a cooling system to work effectively and efficiently, ALL cooling air must be doing real work. ALL cooling air needs to go through the cylinder fins and oil cooler. My concept is to fabricate an enclosed plenum under the engine. With this configuration, all cooling air is contained to the space and volume under the engine. The air cannot migrate into the wing roots or along the firewall. The air cannot leak out through the gaps between the wing roots and the strakes and the cowls. To make this plenum, the forward baffles will be extended downward along the accessory case to seal off the entire front of the engine. The cylinder baffles will be extended downward to the lower cowl cheeks. A sump baffle will be installed under the engine. A diffuser will be installed in the lower cowl. It will join the sump baffle. The aft baffles will be built per plans more or less. I'm also going to relocate the oil cooler into this high pressure plenum and duct the exit air through the aft baffles.
Why Do I Want To Do This?
I've found over the years that most Cozy IV flyers complain about cooling problems. They spend the first year or so trying to improve their updraft cooling. I am running a larger engine. More horsepower, more heat. I want my cooling to work first flight and every flight. I've had this concept in my head for over 8 years now. It's time to build it and see if it works.