[tgrayson]

Originally Posted by mhcasey

So the heavier airplane flies at a higher angle of attack to produce more lift, which can be slipped into the operating engine creating more stability. It seems the higher angle of attack results in two things, though:

I didn't mention higher AOA, and I don't think one is required. As the wing tilts towards the side, the vertical stabilizer starts tilting upwards, replacing the lost lift. Some rough calculations suggest that the lift provided by the vertical stabilizer is actually greater than the lift lost by the wing bank angle, which would require a smaller AOA for the main wing. Very neglible though.

Another question from my flight school's multi engine packet: "With flaps extended a lesser angle of attack is necessary to produce the same amount of lift. Therefore, P-factor is less as well as yaw.

Probably true, although I've seen no data on it. Suspect the effect is smaller than:

Additionally, flaps increase drag aft of the C.G., providing a stabilizing effect."

Note that drag behind the CG isn't the most important thing, but rather having differential drag. If the upwind flap produces more drag than the downwind flap, the aircraft will have a stabilizing moment.

Is this necessarily true?

For every rule you can come up with, you can almost always find exceptions. However, there is abundant data that shows that flaps tend to increase the directional stability of airplanes.

Flaps also increase drag and therefore power required, so to maintain altitude it seems you might actually need to increase the angle of attack

Remember that Vmc has nothing to do with performance, so yes, the power required will go up and it's possible that the aircraft will not be able to maintain altitude at that airspeed. And, yes, increasing the angle of attack may reduce the power required enough to allow the altitude to be maintained, but that means that you've moved closer to a new, lower Vmc.

even if that means the pitch attitude being slightly lower than without flaps.

Lost me there. Don't you mean "higher"?

My understanding was with flaps extended you may take a trade off and actually increase angle of attack in order to decrease the stall speed?

For trailing edge flaps, no, the resulting AOA will always be lower at a given lift coefficient (airspeed) than an unflapped wing. Leading edge flaps, different story.

Once the rudder is at full deflection toward the operating engine with no more than 5 degrees of bank according to FAR 23, Vmca has been achieved?"

That's probably more accurate, although the bank is at the option of the applicant. And to be more accurate, some airplanes are aileron limited, rather than rudder limited, but probably not an issue for the vast majority of light twins.

Note too, for rudder-limited airplanes, you can reduce Vmc to whatever number you want if you're willing to increase your bank angle past 5 degrees. You'll stall in most airplanes, though.