Kind of a sad engine. The US Navy needed 4.5 mWe electrical generation packages, and Rolls bid on the contract to supply pumped up 501s to meet the requirement. Didn't quite make the mark though. You can only stretch the 501/T56 so far, by relying solely on expansion ratio to make power. To give credit, Rolls did put in newly designed turbine nozzles, and blading, but to pull 4.5 mWe at Marine ISO conditions, burning the junk that lies in the ship's fuel bunkers, just cannot last long, and they don't. At rated output, the first stage turbine nozzles fall right on the Type-II corrosion attack target temp, and at cruise, fall right on the Type-I corrosion attack temp. A double whammy, that deteriorates the hot sections in short order.
Otherwise, kind of a neat engine. If run at 501KB5 output levels, would likely be super units.
Robin.
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