"NaturallyAspirated" (NaturallyAspirated)
08/06/2013 at 16:53 • Filed to: Twin Tuesday
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"NaturallyAspirated" (NaturallyAspirated)
08/06/2013 at 16:53 • Filed to: Twin Tuesday | 1
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So here you go, Oppo.
The Cessna 336 and 337 "Skymaster" aircraft were, as far as I'm aware, unique in general aviation for their twin engine, centerline thrust model which resulted in neither engine being a critical engine.
("Critical engine" refers to an engine on a twin that, when operating by itself, can generate more yaw force than the rudder is capable of counteracting. Many twins have a red arc in the airspeed gauge showing the speed at which there is no longer enough air flowing over the rudder to keep the plane pointed straight. Helpful diagram on !!!error: Indecipherable SUB-paragraph formatting!!! .)
BoxerFanatic, troublesome iconoclast.
> NaturallyAspirated
08/06/2013 at 17:22 |
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It would be interesting to see a dis-associated powertrain version of that.
An on-board engine, be it a piston engine, rotary, or a small turboshaft, that is hooked up to a generator.
Whether the powerplant powers one prop, and the other is electrically driven, or both props are electrically driven, and prop speed is entirely divorced from engine speed...
That might make for interesting variable-pitch and variable-speed prop performance, while keeping the engine at optimal operating efficiency. But probably a ton of extra weight in power systems for high-current energy transfer and electric motor speed control.
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BoxerFanatic, troublesome iconoclast.
> NaturallyAspirated
08/06/2013 at 17:31 |
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There are others, called push-pull twins...
Adam A500, for instance.
And another... based on one of my favorite small aircraft.
The Rutan Defiant:
Based on an enlarged VariEZ/LongEZ premise, with both pusher and tractor props. (the smaller ones have only pushers)
As Ramblin Rover mentioned earlier, there was the WWII Luftwaffe's Do 335 Dornier Arrow, but that is admittedly not 'general aviation', as you mentioned.
It has some stabilization effects, and packaging benefits, but there is some argument about the power efficiency of trying to accelerate the same airmass twice, rather than presenting the two props with two separate air masses, even if that creates yaw moments if unbalanced.