Frequent question: What starts a jet engine?

The compressed air passes through a small turbine on the outside of the engine, causing it to spin. Attached to the turbine is a shaft which is joined by gears to the main engine shaft, and that begins spinning as well. “The blades connected to the engine shaft then start rotating faster and faster,” explains Brand.

How does a jet engine start up?

This starting process normally uses an electric motor to spin the main turbine shaft. … The electric motor spins the main shaft until there is enough air blowing through the compressor and the combustion chamber to light the engine. Fuel starts flowing and an igniter similar to a spark plug ignites the fuel.

How does a gas turbine engine start?

Gas turbine aircraft engines such as turbojets, turboshafts and turbofans often use air/pneumatic starting, with the use of bleed air from built-in auxiliary power units (APUs) or external air compressors now seen as a common starting method. Often only one engine needs be started using the APU (or remote compressor).

What RPM does a jet engine run at?

For example, large jet engines operate around 10,000–25,000 rpm, while micro turbines spin as fast as 500,000 rpm.

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Do airplanes have keys?

Small planes (like the little Cessna in How Airplanes Work) have locks on the doors and ignition keys inside to start the engine. … Commercial jets, on the other hand, have no locks on the doors and no ignition key of any sort. You can hop in, flip a couple of switches and start one up!

What spins the turbine in a jet engine?

In a reaction engine, expanding gases push hard against the front of the engine. The turbojet sucks in air and compresses or squeezes it. The gases flow through the turbine and make it spin. These gases bounce back and shoot out of the rear of the exhaust, pushing the plane forward.

When is the starter on a turbine engine shut off?

Once the turbine section is powered by gases from the burner section, the starter is disengaged, and the igniters are turned off. Combustion continues until the engine is shut down by turning off the fuel supply.

How does an aircraft piston engine start?

Magnetos generate electricity when they rotate. So, to start the engine, the pilot must engage a battery-powered starter that rotates the crankshaft. After the magnetos begin rotating, they supply the spark to each cylinder to ignite the air/fuel mixture and the starter system is disengaged.

What is the richest airline?

By company revenue

Rank Airline Assets
(US$ billions)
1 Delta Air Lines 61.8
2 American Airlines Group 60.6
3 Lufthansa Group 44.4

How fast does a 747 engine spin?

In flight, the fan blades spin at around 3,000 RPM. Any higher and the fan tips start to run supersonically, making a huge amount of noise in the form of a piercing drone. In contrast, the low pressure shaft spins at 12,000 RPM and the high-pressure shaft at around 20,000 RPM.

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How hot do jet engines get?

Today’s commercial jet engines can reach temperatures as high as 1,700 degrees Celsius (that’s 3,092 degrees Fahrenheit) because of the highly effective thermal barrier coatings that line the inside of the chamber.

Can you over rev a jet engine?

No “rev limiter” as you are used to with a modern car. Basically it is limited by load (the prop) and the maximum amount of fuel and air it can flow.