Originally Posted by
b1lanc
Well, 'E' is close to 'P' on the keyboard
Kind of ironic that that airframe that once had a tendency to shed wings at altitude is strong enough still to fly through these massive hurricanes 50 years later.
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. Boeing had supplied a hydraulic driven rotating unbalanced weights system to drive wings into flutter mode during test flights- what that proved was that the wing was much stiffer than expected such that the usual flutter exitation modes had little or no effect.
The basic fix was to strengthen and redsign the engine mounts. There are several reports/books writtten about the issue and some of the sphincter tightening tests run at over max speed in VERY turbulent weather of the sierra wave and then turning on the unbalanced weight vibrators out on the wing tips .
Of course there has always been the ' argument ' that a more flexible wing might- repeat MIGHT- have avoided the issue initially.
but in any case the fix proved more than satisfactory- but killed the commercial version of the electra ..