Contents
Where is APU located in aircraft?
tail cone
The APU is a small jet engine which is normally located in the tail cone of the aircraft but, in some cases, is located in an engine nacelle or in the wheel well.
Why do some planes have an engine in the tail?
First, the airplane had to be low to the ground. This way, baggage could be loaded without baggage loading equipment. Positioning the engines on the tail also made a jet easier to control in the event of an engine failure, as the thrust line of both engines was then closer to the centerline of the airplane.
Where is the APU located on a 737?
tail section
For Boeing B737 and B747 aircraft, the APU is located inside a compartment in the tail section of the aircraft and is completely enclosed by a sound-reduction fire-proof titanium shroud.
Where is the APU located on an aircraft?
APU – The little turbine engine. All large commercial aircraft have an auxiliary power unit onboard, usually located in the tail of the aircraft (although some regional jets vents to the side). This is a small turbine engine, essentially the same design and operation as the main aircraft engines but on a smaller scale.
What happens when an APU is removed from an engine?
Pressure then builds up to further spin the engine and, once it reaches its idle power speed, the supply from the APU is removed. The other engines are then started, using either the APU or high-pressure air from the already started engine. This is known as ‘cross bleed’ and is also a technique used for re-starting a failed engine.
What is the main function of an APU?
The other main function of the APU is to start the main engines. As with ground power, this could also be achieved using a ground-based supply. Just as the APU is started using battery power to turn the blades, the blades of the main engines must be turning before they can be started.
How is air supplied to the APU turbine?
Air supplied from the APU to the engines is at very high pressure, so traveling the distance to the engines has minimal effect. If you look carefully at the aircraft tail, you can also see an inlet valve for air for the APU turbine (this will be closed during flight).