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Modern day commercial jets have separate Auxiliary Power Units, or APUs. These are used to supply electrical, hydraulic, and pneumatics while on the ground and, if needed for emergency back-up, in the air. The main engines, once started, are capable of supplying all of these needs in addition to the required thrust for flight. Under some conditions, pneumatics from the main engines may be reduced or shut off during takeoff or emergency conditions to increase available thrust to the engines. Modern commericial jets extract bleed air from the engines to operate the air packs that provide heat to the cabin during its flight. On most engines that I deal with, this bleed air is taken from two locations on the engine compressor: a low-pressure and a high-pressure stage of the engine. The low-pressure stage is about Stage # 7 or up to #10 and the high-pressure air is taken from Stage #14. The high-pressure bleed air is used for most normal demand and the low-pressure is used for peak demand. Engine description: Most commericial jet engines are high-bypass turbojet engines. The first stage is the large fan in front and then there are successives rows of blades that compress the air which increases the air pressure and temperature. After passing through the compressor stages, fuel is injected and the air/fuel mixture is ignited and the explanding gases go through another series of rows or the turbine stages. During take-off, the aircraft will shut off the bleed air so that the engine can produce its maximun thrust. I understand your Question to mean: What percentage of bleed air is extracted from the engines during normal operation? More of the answer to follow.
What else can I help you with?
Type of engine used to power space flights?
rocket engines,compared to jet engines
What energy source was used to power steam engines?
water
Why are radial engines not used anymore?
too much torque and not efficient enough
How much power can a steam engine produce?
The power output of a steam engine can vary widely depending on its design, size, and application. Small steam engines may produce only a few horsepower, while larger, industrial steam engines can generate thousands of horsepower. For example, the steam engines used in locomotives typically produced between 500 to 2,000 horsepower. Ultimately, the specific power output depends on factors such as steam pressure, engine efficiency, and operational conditions.
Distinguish between primary memory and auxiliary memory?
the main memory is the central storage unit of the computer system. it is relatively large and fast memory used 2 store the programs and data during the computer operation.main memory communicates directly with the CPU. main memory includes RAM and ROMs. devices that provide backup storage are known as auxillary memory. auxillary memory are relatively slow in comparision to the main memory. auxillary memory includes flash memory,magntic disks and floppys. main memory is located inside the CPU but auxillary memory is located out the CPU. the main memory is the central storage unit of the computer system. it is relatively large and fast memory used 2 store the programs and data during the computer operation.main memory communicates directly with the CPU. main memory includes RAM and ROMs. devices that provide backup storage are known as auxillary memory. auxillary memory are relatively slow in comparision to the main memory. auxillary memory includes flash memory,magntic disks and floppys. main memory is located inside the CPU but auxillary memory is located out the CPU.
Why is aircraft battery is used in aircraft?
Aircraft batteries are there primarily to provide power should the engines fail in flight and work individually or alongside the auxillary power unit (APU). It provides 28V dc electric to the primary displays (i.e. Altimeter and EHSI).
Type of engine used to power space flights?
rocket engines,compared to jet engines
Steam engines were first used to power?
Machines in factories
What energy source was used to power steam engines?
water
Where did the term horse power come from?
Horse power is a measure of the power output of engines using the pulling capacity of a draft horse as its base unit. It was originally used to compare the power of steam engines compared to horses and was later extended to included petrol and diesel engines.
The fuel used to power most automobile engines comes from?
non renewable
Why is petroleum such a valuable resource to our society?
used to make plastic and power engines
What type of materials are engines made of?
Most engines are made of cast iron, some are aluminum alloys those are pretty much the primary materials used for engines. presently engines are designing with plastic. These engines are used in racing and high end cars.
Power for biplane?
2 wings, to determine which engine was used need to know what biplane
What was steam engines first used to power?
Pumps, to remove water from coal mines.
What was used in the preelectronic period for power supply?
Steam engines, water wheels, etc.
How many stand by engines does a airplane have?
In the Air, the Plane flys on the engines on the wing. If an engine goes out the engine stays out and it flys on the remaining ones. On the ground the Airport may have a few engines available to swap out if something is drastically wrong with the engine. Commericial Passenger aircraft have an Auxillary Power Unit (APU) that is a turbine engine that provides electrical and hydraulic power for emergencies or while a/c is parked on the ground. The Boeing 747 has its APU mounted in the tail--that is the exhaust you see when you look at the hole in the tail. Boeing 727 have an APU mounted in its wheel well; its inlet is on one side the the exhaust is on the other side. Usually on the ground, the aircraft is plugged into ground power carts and air conditioning carts, but the APU can be used.
