Clink, Clink, Clink
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Joined: Oct 2000
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From: NC USA
Clink, Clink, Clink
Just yesterday I was out and about working. My travels took me to the Greensboro airport. I noted 7 L-1011's of various apparent heritages. On my way out I drove past 4 which were parked at one corner of the airfield. The four, with IAG markings looked to be in pretty good shape, although one was missing a few cowlings and engine covers. Now for the question- close up on one of the A/C the 1 and 3 engines were windmilling. At least one was making a consisting clinking sound, fairly loud and inconsistent. Can, over time, engines be damaged this way? Thanks in advance.
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The clinking noise is caused by the turbines.Under normal operating conditions The attachments between the turbine blades and shaft are very hot and is spinning very fast so an expansion gap is left. This causes the individual blades to be "loose" when cold and turning very slowly. Thus the clinking noise is when each bade reaches the top of the circle it drops down towards the shaft, and at the bottom of the circle it drops away from the shaft.
In general it wont do any harm to the engine over short periods of time. However stored aircraft would more normally have covers fitted, both to stop windmilling and prevent animal infestation, sand or dirt.
Hope that helps.
In general it wont do any harm to the engine over short periods of time. However stored aircraft would more normally have covers fitted, both to stop windmilling and prevent animal infestation, sand or dirt.
Hope that helps.
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Joined: Nov 1999
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From: EGGW
That sound is the fan blade part span shrouds (clappers) contacting each other as the fan rotates. the shrouds are there to control the spanwise airflow as the engine turns and also to damp out vibrations. They also limit the amount of movement of the blade in the hub.
part span shrouds
part span shrouds
