Has Anyone Designed a Four-Spool Engine?

[avinod4all]

Actually, we have three spool, two spool engine and single spool engines, how about the four spool engine? did anyone came across the design of four spool engine? I think adding an extra spool leads to increase in engine weight and becomes more complex in its mechanism.

 

[physixlover]

'No' I have never come across a 4 spool engine, and yes it would be more complicated and causes lots of maintenance problems for a four spool engine, I would better suggest to discuss about a three spool or two spool engine in this thread.
Major advantage of triple spool design is it's ability to minimize engine surges thus they are the most efficient engine flying.