"Gerry Caron" wrote in message
om...
I think your confusion comes from the idea that the heavier plane has to
fly
faster at the same AOA to generate lift equal to weight. At that higher
speed, the total drag will be higher.

The drag would be higher even for equal airspeeds. As you already stated,
induced drag is proportional to angle of attack and *lift*. At higher
weights, lift is necessarily higher as well, increasing induced drag.

Now, you may consider that a secondary effect rather than a "direct effect"
(though I don't). But you ought to at least mention it. Your post seems to
be saying that weight does not in and of itself increase drag, but weight
does do exactly that.

The minimum drag point is the point of least thrust required. But that's
not best L/D.

Why not? Lift is constant for a given weight, so the best ratio of lift to
drag will occur where drag is at its minimum. Seems to me that the minimum
drag point IS exactly the same as the best L/D point.

Pete