Simviation Forum - Starting up the jets

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Starting up the jets (Read 190 times)

Feb 15^th, 2005 at 8:14pm

jrpilot Offline
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does anyone know how long it takes a pilot to start a jet up..it takes me to start up the Wilco CRJ about 5 minutes (I just started with her again and have to get used to the button)

I have some DVDs of start-ups and the pilots just fly thorugh it I know they just didn't learn to fly yesterday but DAMMM they are fast...calling N1, N2 rotation...etc

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Reply #1 - Feb 15^th, 2005 at 8:22pm

Craig. Offline
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In the end its like starting a car. Once you know how its not difficult. Thats why it takes hundreds of hours of learning to fly to get to the point.

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Reply #2 - Feb 15^th, 2005 at 10:03pm

jknight8907 Offline
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I think it depends on the particular jet. (jet=engine, not jet=the plane)

Basically what happens is the turbine is spun up using either an electric starter or bleed air. After the turbine reaches a certain N1 percentage, fuel is turned on and ignited by the ignitors. After the jet is running, the ignitors are turned off. It's important that the N1 percentage gets high enough before combustion is initated, or else there isn't enough air moving through the turbine and you basically have a Jet A-fueled furnace burning in there; this is known as a 'hot start' and depending on how bad it is, can be very very expensive to fix.

&&It is better to remain silent and be considered a fool, than to open your mouth and remove all doubt.&&&&There were once four people named Everybody, Somebody, Nobody and Anybody. Somebody had to do a job, but Nobody wanted to do it. Nobody could see that Anybody could do it, and Somebody got angry about that because it was Everybody's job. Nobody ended up doing it, and it so happened that Everybody blamed Somebody when Nobody did what Anybody could have done.

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Reply #3 - Feb 16^th, 2005 at 7:04am

Nexus Offline
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Good explanation, but you are confusing the N1 with the N2 (HP compressor)

It's the N2 RPMs that has to be high enough to provide sufficient airflow to support combustion. Usually you'll add fuel at around 20-25% N2 (depending on engine)
If the compressor can't supply enough air and you add fuel, chances are that you'll get an engine hung start...ummm...and that's not funny aswell

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