Engine Cylinder Cooling Fins, Baffle and Deflector Systems

The realm of aerospace and aviation, as I suspect you’ve heard plenty times before, a strictly and heavily regulated one. From who can manufacture or repair what to how long or for many cycles a part can be in use, every aspect is subject to intense scrutiny. So, it should come to no surprise that things like engine cylinder cooling fins and aircraft engine baffle and deflector systems also have rigorous inspection requirements.

Cooling fins are a major part of the engine cooling system because they provide a means of transferring cylinder heat to the air. Their condition can mean the difference between adequate and inadequate cylinder cooling. As a result, during each regular inspection, the fins are inspected and examined for cracks and breaks. Small cracks are not reason for removal as they can be filled or stop-drilled to prevent further cracking. Rough and sharp corners can be filed and smoothed to prevent further cracking. The definition of fin area is important in determining whether or not the cylinder is removed. For example, on some engines, if one fin exceeds 12 inches of damage, or if the total area of broken fins in any one cylinder exceeds 83 square inches, the whole cylinder is removed. Inspectors should always consult the manual for specific details and instructions.

Cylinder baffle and deflector systems force cooling air into close contact with all parts of the cylinder. The baffle blocks the airflow and forces it to circulate between the cylinder and deflectors. The baffles and deflectors are also inspected during regular inspection, but should also be checked whenever the cowling is removed. They should be checked for cracks, dents, or loose studs. If cracks or dents are severe enough, they will need to be removed and repaired or replaced. Smaller cracks and dents can be stop-drilled and straightened respectively.