Inherently unstable at any speed....
All the flight control software in creation cannot prevent a certain spin and likely tumbling should one of those two engines hiccup or fail at a critical moment...
There are design engineers who enjoy their artists' sketches and pipe dreams...
--AND--
There are pilots who live with the daily line-flying realities and variables of transport aviation...
Including staying safe in the context of all the reasonable "what-if's"...
--"what's the next unexpected thing"...
and the "one-more-thing" to deal with...
(usually external factors--weather... traffic conflict/delays... etc.)
When engineers and pilots work together...
...the new generation aircraft are that much more safe, fuel-efficient, and cost-effective...
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LOCKHEED was the BEST!...
BOEING is VERY GOOD at this...
McDONNELL-DOUGLAS [RIP]... fair to midline....
--AND--
SCAREBUS.... not so much at all...
JMHO
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Have a nice flight...