Thanks Ack. Never knew they had any at all the turned inward.
You're both correct about the torque by the way. I'm just tossing out some additional info. Yeh I know I tend to ramble some times, but it keeps me in practice for teaching ground.
General FYI stuff for critical engine (and torque
)....
Book definition of critical engine: engine that will have the most adverse effect on the aircraft if it fails.
In a conventional twin (props both rotate to the right from the pilots view) the left engine is the critical engine because the thrust line is closer to the centerline of the aircraft. This means that the thrust line on the right engine has a longer arm to the centerline (almost a duh thing but that's how simple we're supposed to teach it). If an engine fails, the thrustline, p-factor, and torque on the remaining engine will create a rolling moment. Right engine having a longer arm, creates a larger rolling moment.
On small trainers like the seminole and duchess (180 hp whee) it's so slight and slow that you could go out for coffee, come back, and still recover. Plus they're counterrotating inward.
You step up to the high horsepower planes and if you don't catch and correct it
immediately it's gonna roll you over rather nicely. If you were to lose the right engine, you'll still have all the nasty factors acting on the aircraft, but because the arm on the left engine is closer to centerline, the effect isn't "as" great. Although, I'd be willing to bet in 38 it would still roll you over rather nicely if you didn't catch it.
What I still miss on the 38 is that turning inward or outward would have the same effect on torque. But, outward makes the thrust arm to centerline longer on *both* sides. Just curious as to why they chose outward. Would be interesting to hear the aerodynamic reasoning they had during design. Best speculation (note the speculation) I've heard so far has to do with the way the spiraling slipstream hits the the twin vertical stabs.
