Howdy!

In article ,
RST Engineering wrote:
No, the Lockheed Electra (turboprop, Allison engines) started falling out of
the skies shortly after their introduction. I believe the first one was
over Wink, TX and there were a couple more shortly thereafter. All sorts of
goofy reasons were tossed around, all the way from wrong rivet sizes to the
biffy leaking effluent onto the spar. The root cause was a peculiar
vibration of the engines called "whirl mode". THe fix was neither trivial
nor inexpensive. We had four of them at PSA and those damned things just
would NOT quit on you. They were also the easiest to work on transport
class aircraft I ever encountered.

....where the engine wobbles in a conical sort of motion. IIRC, the
turboprops had enough horsepower to get into that sort of vibration where
the classic round engines didn't. New turf with extra wrinkles, as it were.

yours,
Michael


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Michael and MJ Houghton | Herveus d'Ormonde and Megan O'Donnelly
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