On Tuesday, October 23, 2012 6:03:13 AM UTC+13, jfitch wrote:
On Monday, October 22, 2012 6:11:38 AM UTC-7, JohnDeRosa wrote:

I was asked last night "Why don't commercial airliners (747, A380,



etc) have 'super wings' like gliders?" I mumbled something semi-



coherent but didn't really know the correct answer.







So, would high aspect ratio and highly efficient glider-like wings



enhance fuel economy for all airplanes? What are the engineering



tradeoffs for wing design between a hulking airliner and a slim/trim



glider?







Sign me "I ain't no AeroE".







Thanks, John



Nearly all powered aircraft cruise at speeds way above stall. That means the lift coefficients in cruise are low, therefore the induced drag (proportional to Cl ^2) is low, therefore aspect ratio is less important.

Not really true of jet airliners. They fly so high that although they're going fast they're at a pretty big angle of attack and not all that far from the stall.