PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Tech Log (https://www.pprune.org/tech-log-15/)
-   -   jet engine siezure (https://www.pprune.org/tech-log/257676-jet-engine-siezure.html)

punkalouver 27th December 2006 19:59

jet engine siezure
 
If this were to happen, especially an LP compressor, will it create more drag than a windmilling engine. Any further precautions?

super 27 27th December 2006 20:40

in my opinion it will create less drag :hmm: than a windmilling engine

Milt 27th December 2006 21:42

In my opinion it will cause more drag than a windmilling engine!!

issi noho 27th December 2006 22:20

Why did it seize and is there any other damage, do I care about the drag if I can control any Yaw it is causing?

In my opinion more drag.

Old Smokey 28th December 2006 03:50

A siezed jet engine will cause LESS drag than a windmilling one, for all the same reasons as for the windmilling/stationary propeller.

For a siezed engine, there is only the form or profile drag of the engine. For a windmilling fan, it is extracting energy from the airstream to drive the compressor and other engine accessories. That will cause more drag.

If you can get your hands on the Performance Manual for your aircraft (the one used by Performance Engineers) there are two sets of Drag coefficients provided for a failed engine, one for windmilling, and one for stationary. In all cases the Cd for the stationary engine is less than for the windmilling engine. Performance is predicated upon the engine windmilling, i.e. the worst case.

Regards, and Happy New Year,

Old Smokey

GroundedDragon 28th December 2006 06:30

I was flying on a 747 that was ferrying an engine and got to discuss this with the pilot. He said that they don't let them windmill because of the drag, and because of moving parts not being at the proper operating temperatures (clearances, etc).

Pictures:
http://www.!!!!!!!!!!!!!!/open.file/783444/M/

http://www.!!!!!!!!!!!!!!/open.file/763404/M/

http://www.!!!!!!!!!!!!!!/open.file/0289429/M/


All times are GMT. The time now is 05:35.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.