WARM UP BEFORE TAKE OFF
I was at a presentation given by a rep from CFM some years ago who said that in an ideal world they would like to see their engines run for 10 minutes prior to setting take off thrust. He maintained that this would be of great benefit to the engines longevity.
SOP on the Boeing flightline is 5 minutes after a 'cold' start before advancing to high power. Doesn't matter what engine type.
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The warm up prior to take off power on 146/RJs with ALF502/507 is three minutes.
If the engine has been shut down for less that 30 mins then no warm-up required.
Not really Boeing related but if those temperamental engines can be okay after three min I'm sure the CFM's on the Boeings are good...hahaha
If the engine has been shut down for less that 30 mins then no warm-up required.
Not really Boeing related but if those temperamental engines can be okay after three min I'm sure the CFM's on the Boeings are good...hahaha
No need to judge good or bad about engines and warm ups.
As the efficiency of the engine designs improved over 50 years, the clearances over the blade tips needed to get tighter. Unfortunately differences in thermal expansions between parts works to defeat the exactness of this clearance either too little and it rubs causing permanent wear. While too much and the efficiency and/or stability goes to hell.
Be kind to your engine and follow the instructions that came with it
As the efficiency of the engine designs improved over 50 years, the clearances over the blade tips needed to get tighter. Unfortunately differences in thermal expansions between parts works to defeat the exactness of this clearance either too little and it rubs causing permanent wear. While too much and the efficiency and/or stability goes to hell.
Be kind to your engine and follow the instructions that came with it
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The "bowed rotor" phenomenon is discussed on the last half of this thread.
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146 has no engines, only 5 APUs. Would have had 7, if there was the room.
The old joke are still the best; Ha ha: it must be the way ya tell 'em. Hee hee!
The old joke are still the best; Ha ha: it must be the way ya tell 'em. Hee hee!
There is hurting the engine, and there is HURTING the engine. On the Boeing flight line, the engines are brand new and the focus is minimizing any deterioration before we hand over to the customer. 5 minutes is pretty good for that. Making sure the engine doesn't surge or do something similarly unpleasant is different and is more engine dependent.
