WARM UP BEFORE TAKE OFF

Joined: Apr 1999
Posts: 447
Likes: 1
From: wherever I lay my hat
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.

Joined: Jun 2014
Posts: 102
Likes: 0
From: Canada
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
Joined: Mar 2002
Posts: 4,569
Likes: 1
From: Florida
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

Joined: Feb 2005
Posts: 4,581
Likes: 0
From: flyover country USA
The "bowed rotor" phenomenon is discussed on the last half of this thread.



Joined: Jul 2013
Aviation Qualifications: Non-Aircrew
Posts: 5,682
Likes: 3,347
From: Everett, WA
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.




