In article , "Darkwing Duck \(The Duck, The
Myth, The Legend\)" writes:

Anyone know what those fins/blades are all about?

It was another one of those projects that looked good on paper, but in the end,
was more cost and trouble than it was worth. There wasn't enough of an
increase in efficiency to make the effort worthwhile, while at the same time
there were noise and vibration issues that would have been expensive to
resolve.

I do remember watching it land at LGB while I was at school there. It made a
rather distinctive sound.

I know that at least one of those engines is in the Smithsonian now.

John