On Mon, 13 Feb 2017 09:36:34 -0800, Jim wrote:

Yes. I understand that. If the glider is not to accelerate downward
the total "lifting force" equals the current gross weight (and drag
vector too I guess) of the glider. My silly curiosity has been about
exactly the point you make. Everything else being equal ( I know, never
happens), does a wing that supports 10 lbs per square foot of wing area
require the same TOTAL"lifting force" as a wing that supports 5 lbs per
square foot of wing area - but has twice the wing area? IF this is the
case it would suggest that the glider with half the wing loading but
twice the wing area could be sustained by a smaller "lifting force".

Depends how you define 'lifting force'.

If you define it as the total lift generated by the wing, then it will
not vary with the wing area because it will always match the weight of
the glider.

If, OTOH , you define it as the lift generated by a square foot or square
meter of wing, then doubling the wing area will halve the 'lifting forge'
per unit of wing area because, again because the total lift generated by
the wing will match the glider's weight.

What does change as the wing area is varies are a number of factors that
contribute to the wing's total lift and drag, such as skin friction
(varies with wing area) and tip vortex drag (varies inversely with wing
span for a fixed wing area).

For a descriptive treatment, i.e. minimal numbers or equations, of this
and other topics I suggest you read:

Stick and Rudder - Wolfgang Langwiesche

or visit the av8n website, http://www.av8n.com/

Both are written to give a private pilot a better understanding of how
and aircraft flies and both are equally applicable to gliding.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |