Basics of an Aircraft Exhaust System

Of the various components that contribute to an aircraft's performance and longevity, one of the most overlooked is the aircraft exhaust system. The exhaust system's purpose is to remove the hot and toxic gases created by the engines. This exhaust would otherwise be damaging to the integrity of the plane and the health of the passengers. This blog will discuss the typical exhaust systems found on two common engine types, jet and reciprocating.

Several components make up a gas turbine exhaust system, and they all work in unison to direct the flow of the high-velocity exhaust gas. In most jet engines, the cone, exhaust pipe, and nozzle make the exhaust section. The cone collects the gases from the turbine section and funnels them into a steady flow of gases. By doing this, the overall speed of the gases is decreased while the pressure is increased. The cone is made of two smaller components called the outer shell and inner cone. The outer shell collects exhaust gases and directs them straight to the exhaust nozzle. Simultaneously, the inner cone works to prevent turbulence that the discharged gas may cause. Not every aircraft's exhaust system includes an exhaust pipe, but if it does, it is designed with capabilities that allow for thermal expansion. Unlike other parts of the exhaust system, the nozzle takes the energy from the gas and converts it into propulsive force. Therefore, the shape of the nozzle will depend on the desired velocity that the nozzle will bring the jet to. A converging design is used for subsonic speeds, and for supersonic speeds, a converging-diverging design is chosen.

Reciprocating exhaust systems are more straightforward, but their design will also vary based on the aircraft. The two general categories for these exhaust systems are the short stack and collector system. The short stack design is used on low-powered engines where noise isn't a concern, while the collector exhaust is used on louder supercharged engines. On modern aircraft, collector exhaust systems are much more common. The significant difference between these two systems is that in a collector system, exhaust gases must be collected and sent to the supercharger's compressor.

In any exhaust system, each component is critical and must be properly functioning and free of debris. While exhaust systems typically have a long life span that is free of maintenance issues, it is essential to know about some common problems that may occur. For example, the exhaust pipe may have leaks due to improper alignment with another component. These leaks will look like a black streak on the pipe, and if noticed, one should immediately investigate further. Another severe problem that could occur is a faulty or burnt exhaust valve. Exhaust valves are part of the individual cylinders of the engine and should remain closed during the combustion cycle. These valves are constantly exposed to extreme temperatures, but can usually withstand harsh operating conditions. There will be low engine power in a failure, and one would hear a loud popping noise. Finally, mufflers are generally overlooked or quickly looked over without entirely removing the shroud. If a muffler were to become dislodged during flight, the entire exhaust outlet could become restricted, and power loss could occur.

The importance of exhaust systems cannot be overstated. These systems directly affect the longevity and performance of the overall aircraft. For all of your exhaust system needs, ASAP Supply Chain is your number one source. We are a leading online distributor of exhaust systems and millions of other aircraft components. Additionally, we are the only independent distributor with a No-China sourcing pledge. Instead, all of our inventory is sourced from reliable manufacturers that are on our approved vendor list. Furthermore, we offer rapid shipping and a responsive and knowledgeable team of account managers and sales representatives. Browse our vast inventory, and don't hesitate to contact us with any questions you may have. We look forward to helping source your next aviation project.