Flight Safety,
With my engineer's hat on I might see a need to clarify a point or two .. but with a pilot's hat on ... I think that you have the idea sufficient for the need ....
The wing lift is distributed along the span rather than acting at the tips. If you like to think of a centroid for the lift (similar to the rule analogy I gave before), rather than a distributed pattern, then the centroid (mean lift position for the half span if you prefer) will be somewhat inboard of quarter span for each wing.
Keep in mind that my description was intended to be a general overview for a pilot's interest ... the engineering detail gets a little more involved but, really, is not necessary for a descriptive overview....
Last edited by john_tullamarine; 3rd Sep 2002 at 14:19.