by Sonerai13 » Wed Nov 04, 2015 10:19 am
Recently we were made aware of a builder who flew his airplane without the cowling installed. I thought it would be appropriate to post a reminder to the group that this is NOT a good idea. The cowling forms the top of the cooling plenum. This forms the high pressure area above the engine that forces air down through the cooling fins on the cylinders and heads. Air is a fluid, and like all fluids, it seeks the path of least resistance. If the cowling is not in place there is no plenum formed and nothing to force the air down through the cooling fins. Thus, the air will simply flow around the engine and not through the fins and you have no control over what, if any, cooling is taking place. Your CHT may or may not show a problem, but there's no way to know if there are hot spots in other areas of the cylinders or heads. The only way to make sure you are getting complete airflow through the cooling fins is to fly with the cowl in place.
Joe Norris
Sonex N208GD (S/N 450)
Sonerai II N13NN (S/N 1206)
Fortes Fortuna Adiuvat