Originally Posted by
CONSO
Actually the problem was weak engine mounts which allowed the turbo props to go into a ' whirl mode" due to gyroscopic action which reached the natural frequency of the whole wing structure- not really flutter as usually defined.
I read through the LEAP report - seems that "damaged powerplant installation" was a key - some discussion of repeated 'hard landings' damaging the mounts and the supporting braces was a suspicion but didn't address the design flaws in the first place. Makes me curious if as the new turbo-prop entry into the market, 'hard landings' were part getting used to type. I'm sure there were some stiff hits when jets hit the market due to spool up time.
Always wondered how the other props rode - only experience was a number of DC-6 trips between LaGuardia and Cleveland but I kind of remember the wings as being rather stiff - little bending and we did hit some really awful turbulence going through fronts and storms over the PA mountains. Watching the wings flex a couple years later on my first DC-8 and 707 flights, thought sure they were going to fall off so I'm guessing my prior prop flights at a young age set some internal expectation that wings shouldn't flex.