Originally Posted by Pugilistic Animus
...the biggest problem is pitching it in a reasonable way so those without the appropriate math and physics background could also understand....
I agree.
Sometimes you have a simple analogy at hand to explain things, like a stone and a rowboat in water to explain the sonic bang. Sometimes you just do need the basic math and physics.
Originally Posted by kenparry
Take an untwisted rectangular wing planform, so the span-wise lift distribution is definitely not elliptical."
No, but nor is it linear across the span - downwash affects the distribution, and the lift is biased towards the inboard sections. Don't try to get too deep into this: if you want to do it fully you will end up with pages of highly complex equations, and probably wish you had not started.
I know what you're saying... I was just trying to visualise a situation where inboard flaps could actually decrease
induced drag. Not total drag, obviously.
Originally Posted by Mark1234
However, the induced component of drag would seem slightly irrelevant, as it's rather impossible to separate from total (induced + parasite) in practical terms.
You're right in general terms, I would say, but I think you are missing the point...
Induced drag, i.e., drag due to lift, may be difficult to separate from total drag at first sight, but it can generally be computed quite accurately and the computations usually match real-world measurements very closely. So it's a valuable tool to separate the drag due to lift from the rest.
CJ