Why Cowl Flaps?
Although the last couple of decades have seen attempts at liquid cooling for general aviation (GA) engines, most light-plane powerplants still depend on external airflow for cooling. Cowl flaps increase cooling air flow through the engine compartment and around cylinder cooling fins. They also add air flow through the oil cooler, which is basically a radiator required to keep the inside of the engine more cool. If you’re flying a turbocharged engine with an intercooler, cowl flaps may also help offset the heat of turbo boost, increasing available engine power. How Cowl Flaps Work An opening or door at the rear of the engine cowling, cowl flaps deflect the slipstream enough to create a low pressure area in the bottom of the engine compartment. Some designs may have cowl flaps on the sides of the cowling as well. Reduction in air pressure itself helps cool the engine; but more importantly, the low pressure that cowl flaps create pulls air through the engine compartment for increased cyli
