The Starter - Turbine Engines: A Closer Look

Electric starter installation in the front accessory section of the GE J47 turbojet engine

Category:

Autos & Vehicles

Tags:

• J47
• J-47
• jet
• engine
• GE
• electric
• starter
• motor
• generator
• S&S
• FSJ
• joljbc

[michaelcrowe1]

Re: my other comment. I see from the Auxilary drives video that the starter also serves the purpose of becoming an electrical generator once the engine is running

[AgentJayZ]

@michaelcrowe1 This engine is of a very old design, and it is about the upper limit in size that an on-board electric starter is used for. This starter does become an electrical generator once the engine is running.

[13thChip]

why is that the Airplane's Batt not used for starting the Engine to idle speed? One of your videos showed an yellow external starter but was powering the engine to idle speed using high flow Air. Do engines have both options or just one? And what decides if it should be started by Air or DC? Having said that I know that one engine can power up the other using the same AIR technique. So an engine has both the options ? What type of starters are used in Passenger flights?

[AgentJayZ]

@13thChip All the engines in all the large modern transports are started with air turbine starters using air supplied by ground power units for the first engine. Then yes, many of these aircraft can then use bleed air from the compressor of a running engine to start the others.

[princejaa]

@michaelcrowe1 As far as i know. the starter only puts out a great amount of current to turn the engine. once engine is in motion the Generator takes over. the starter has to disengage. if not you might overspeed the engine with such great torque.

on smaller aircraft, the Magnetos take over. hope that helps.

[princejaa]

@13thChip Batts dont have enough power to start the engines. so they use GPUs (Ground Power Units) to run the Engines. and on large Aircrafts the GPU is used to run the Aircraft APU (Auxiliary Power Unit)

Batts are only used on smaller aircrafts. hope i helped..

[krbruner]

On the Auxiliary Drives clip for this same engine, you said that the starter was a starter/generator and provides power for the aircraft, but in this clip, you said that it is only to run for 45 seconds to start the engine. I also noticed the speed listed as 3k/8k. Is there a automatic clutch/gearbox or something that allows it to switch from low rpm/high torque to start(which requires the low duty cycle), then low torque/high rpm to generate?

[michaelcrowe1]

how does the starter disengage once the engine is running? it didn't look like the starter had one of those electromagnetic "push-out" pinion things that engage on the ring gear of a light aircraft engine

[AgentJayZ]

@13thChip Sometimes you can airstart a turbine engine in flight.

[13thChip]

@AgentJayZ : Perfect answer. Guess both engines never stopped during flight and if they do stop, can the engines still be powered ON? The wind is enough for the rotors?

[marcosaba360]

hey monster guy agent ! another monster video !