Single Aircraft Engine Performing Multiple Functions: APU
Read Ahead: Bringing a Third Engine on Board – the Secret Star of Flight!
No, this isn't about a spy mission or a magic trick. We're talking about an APU – the Auxiliary Power Unit that most two-engine jet airliners hide as the plane's unsung hero! You might be thinking, "Wait a minute, the third engine in a two-engine plane? Where?" You're on the right track!
Meet the APUs – The Engines You Don't See
When you see a commercial airliner jet past, you'll notice the two primary engines boosting the aircraft into the sky. But out of sight, tucked away in the tail section, there's a third engine known as the APU (auxiliary power unit) – a small but mighty engine that plays a crucial role in getting the plane off and cruising smoothly!
APU's Multiple Superpowers
The APU is primarily used to provide electrical power and compressed air, both on the ground and occasionally in flight. It does not, however, offer thrust like the main engines, and that's by intentional design!
During ground operations, the APU's electrical power is essential for starting the main engines, lighting up the cabin, powering the avionics, and running all the onboard systems. It also helps in providing air conditioning to keep the passengers comfortable and ensuring the crew can prepare for takeoff in style!
Facing a real struggle to take off? Most commercial airliners would prefer not to, thanks to their loyal APUs!
Want to know the details behind this magical engine? Let's dive deeper!
How APUs Work Their Magic
Normally, a gas turbine engine powers the APU, whispering away in the tail section of an aircraft. This functioning is quite similar to a conventional jet engine, drawing in air, compressing it, combining it with fuel, and igniting the mixture to produce exhaust gas.
However, instead of propelling the plane forward, the exhaust gas is channeled to another turbine at the back of the APU. This turbine powers the front one, leading to faster spinning speed – drawing in even more air! This cycle of air intake, compression, fueling, ignition, and exhaust continues, delivering efficient power to run the essential services.
APUs – The Unsung Heroes of Aviation
Bleed Air
The APU produces an air known as bleed air, which is invaluable in engine starting and cooling the cabin air during flight.
Electricity
APU also makes electricity using its driveshaft to turn a generator, powering all the aircraft's electrical systems, including cabin lighting, avionics, and flight control computers.
Backup and Engine Redundancy
APUs are designed to serve as backup power in case of emergencies, ensuring continuous operation of vital systems such as the aircraft's electrical power and temperature control.
APUs may seem small, but these powerhouses help set commercial jet airliners apart – increasing their safety, reliability, and efficiency!
Wrapping Up
APUs: Small but mighty, the hidden engine that powers commercial aviation. Giving flight crews the flexibility to prepare for takeoff, manage cabin temperature, and ensure critical systems run reliably, APUs are a vital player in the aviation game. Travel the skies with confidence, knowing your trusted APU has your back!
So next time you board a flight, don't forget to give a little nod to the mighty APU, the plane's very own secret weapon!
References:
- Airbus (2022) A320 Family. [Online] Available at: https://www.airbus.com/products/commercial-aircraft/a320family.html
- FAA (2022) Auxiliary Power Unit (APU). [Online] Available at: https://www.faa.gov/aircraft/air_cert/guide_air/6_aircraft/media/Auxiliary%20Power%20Unit%20APU%20Guide.pdf
- NASA (2016) APUs. [Online] Available at: https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/What-is-an-Auxiliary-Power-Unit-APU-58.html
- National Aviation Hall of Fame (2022) Auxiliary Power Unit. [Online] Available at: https://www.nationalaviation.org/exhibits-and-collections/glossary/auxiliary-power-unit-apu/
Gadgets like APUs (auxiliary power units) showcase the marvelous impact of technology in modern aviation. They offer vital services such as delivering electrical power, compressed air, and even providing backup power in times of emergencies, transforming commercial jet airliners into more reliable and efficient machines. While it's easy to overlook these technology marvels hidden within planes, appreciating their role can elevate the flying experience, making it as sophisticated and impressive as the gadgets we use daily.
