Sorry Shadow: I meant baffling....

In the N.A. MLD-35 Manual, there is a small Q&A section on baffling. Here it is;

"Q22. How important are cooling and baffling for MLD engines?

A22. Baffling is the technique to channel / direct all intake air over the cylinder head, thus forcing air to flow across the engine rather than bypassing it. This is a very effective cooling method on air cooled engines. Deflecting or baffling of the air to and over the cylinder is highly recommended for proper cooling. The idea is to get all of the cool air that is coming through the air intake opening(s) to hit the middle of the cylinder(s) directly, and then be forced over the cylinder(s), creating turbulent air moving through the cylinder(s) fins. The freely flowing, but directed and turbulent air between the fins provides the maximum cooling for an air cooled engine. Without baffling the air (similar to water property) will take the path of least resistance. Some incoming air will bounce off the cylinder(s) and the rest will escape around the cylinder(s) without coming into contact with the cylinder(s).

To ensure constant flow of cold air around the cylinder, and to reduce the air pressure build-up inside the engine cowl, the hot air exhaust exit must have a much larger cross section area than the cold air intake. As a rule of thumb, allow 4 times the area for exhaust air than intake air, this may be achieved by reducing the intake area (as in a radial type cowl) and expanding the exhaust area. Air entering the smaller cowl opening will expand and cool existing at a lower velocity, further aiding cooling of the engine."

Peace,
Steven Chao,
CERMARK