FredT From United Kingdom, joined exactly 14 years ago today! , 2185 posts, RR: 25
Reply 1, posted (13 years 10 months 2 weeks 5 days 13 hours ago) and read 7807 times:
Lots of things. We can start making a list, see how many things we can think of? I'll start with
1) Unbalanced rotors
2) Bent shafts
3) Bearings with defects
I assume you mean jet engines/gas generator related vibrations? If you add turboprops, engine accessories and so on, there's a sh*tload of other potential sources. If you throw recips into the mix.... well, they're vibrating rather severely to begin with but you can still detect lots of things about to go wrong by monitoring vibrations in the right part of the spectrum.
I thought I was doing good trying to avoid those airport hotels... and look at me now.
ThirtyEcho From United States of America, joined Dec 2001, 1728 posts, RR: 1
Reply 3, posted (13 years 10 months 2 weeks 4 days 22 hours ago) and read 7749 times:
Vibration in a turbine engine is caused by loose or bent things; bad vibration is caused by big loose or bent things. Vibration in a piston engine is caused by normal operation; lack of vibration in a piston engine is usually caused by fuel starvation.