Aircraft Engine Baffling : In Detail

Aircraft engine baffling is important in ensuring the engine is properly cooled. Engine baffles and cowls are designed to provide an air-tight seal between the top and bottom of the engine. This seal ensures that cooling air is accurately directed through the engine, oil cooler, and engine compartment preventing the engine from overheating.

In modern piston engine aircraft, the engine is tightly sealed by baffling. Air flows into the cowling through openings in the nose cowl. A system of rigid aluminum baffles and flexible seals creates a chamber of high pressure above the cylinders and a second chamber of low pressure below the cylinders and behind the engine. These chambers seal the gap on top of the engine to pressurize the ai r. Furthermore, the baffles and seals help to direct air over the cylinders from the high pressure area to the low-pressure chamber. This creates an airflow that travels from top to bottom and eventually exits the airplane via additional openings in the cowl. Inter-cylinder baffles direct cooling air into the cylinder cooling fins.

Flexible seals close the gaps between the baffles and cowling. Just as a leak in the radiator can cause a car engine to overheat, a leak in the engine baffle can cause an aircraft engine to overheat. If the seals become loose or brittle, they will be compromised, resulting in air leaking past the seal and insufficient cooling. When this happens, one or more cylinders may be operating at a much higher temperature than the others. The best way to verify that all cylinders are operating at safe and similar temperatures is a multi-channel cylinder head temperature gauge. For continuous operation, the cylinder head temperatures should be kept at least below 400 degrees Fahrenheit, but preferably below 380.

In addition to engine overheating, high cylinder head temperatures can cause faster wear-down of expensive engine components (especially exhaust valves and valve guides), cracks in the cylinder head, and oxidation of engine oil and cylinder bores. When inspecting and refitting baffles and baffle seals, there are six things you should look for:

• 1. Ensure all baffles are correctly fastened to the engine.

• 2. Make sure no baffles are missing, paying close attention to small baffles that need to be fitted around oil coolers, engine mounts, inter-cylinder baffles, etc.

• 3. Ensure that the baffle rubbers have not become worn or torn.

• 4. Make sure that when the cowls are fitted with baffle rubbers there is a good seal. Dust tracks on the inside of the cowl are an indicator of a leak.

• 5. Check that the cooling air pressure during flight is not causing the baffle rudders to fold back, dislodging them from their correct position.

Baffles and baffle seals are not visible unless the cowling has become displaced. Older seals are thin and black, while newer silicone rubber seals are a shade of red or orange. Keeping your engine baffles and baffle seals in good condition is an important task any aircraft owner or servicer should keep in mind. Regular inspection and maintenance will save time and money, as well as ensure that an engine reaches its intended service life.

At AFR Enterprises, we can help you find all types of aircraft baffling system parts and deliver them with short lead times and competitive prices. Additionally, our inventory of more than two billion parts comprises airspeed and fuel management parts and much more. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@afrenterprises.com or call us at +1-714-705-4780. Our team of dedicated account managers is standing by and will reach out to you in 15 minutes or less.