i think this must be more stable largely because the two engines are closer together (effectively one "side boom" is moved to the centre).
couldn't you do even better with a push-me pull-me configuration? then power would always be aligned correctly, whatever failed. perhaps that is less efficient, since the pusher is in the wake of the puller? it wouldn't look so fugly...
I'm pretty sure there's more to it than just that. For example, the difference in power output between the two engines wouldn't be necessary if the enhanced stability were due only to reduced distance between engines.
For example, the Blohm and Voss BV141, an experimental German aircraft, used an asymmetric single engine design wherein the weight asymmetry was balanced by the prop torque, which tends to cause yaw and generally needs to be trimmed out on non-counter-rotating twins and single engine airplanes. [0]
With regard to push-pull config: the Cessna Skymaster was designed this way. There are about 3000 of them flying around, including about 500 in military service, according to Wikipedia [1].
Another amazing aircraft design that never caught on and had some of the enhanced stability properties inherent in closer engine placement was the Beechcraft Starship [2]. For my money, it's the most beautiful business aircraft ever built, and it's got some seriously amazing aerodynamic features. For example, since it uses a canard design, it's very hard to stall: the canards will stall before the wings, which drops the nose, decreasing AoA and increasing lift.
There's an amazing image of a Starship chasing a SpaceShipOne during a test flight on the Wikipedia page.
One of the Starships was based at our local airport for a few years. Very impressive looking aircraft. As I recall, it was a strange sounding beast; much noisier than you'd expect. Haven't seen it around in quite some time, though.
See also the Piaggio Avanti. http://www.piaggioaero.com/ One use to land at the airport near me (I have not seen it in a while). It also had a very distinctive sound (and was quite noisy).
I first found out about the Piaggio Avanti when I downloaded X-Plane 9 for the iPhone. The whole body creates lift and as a result it handles very differently from other small aircraft.
couldn't you do even better with a push-me pull-me configuration? then power would always be aligned correctly, whatever failed. perhaps that is less efficient, since the pusher is in the wake of the puller? it wouldn't look so fugly...