Most "normal" people would probably be surprised that modern airliners have pretty good glide performance. I have a table in some textbook that quotes values of around 17:1 to 19:1 for various models that were current in the 1980s when I was in school. This is about what the Schweizer 2-22 I learned in could do. These glide ratios are typically at about 200kts or a little more, so they sure do penetrate! And in fact, they do tend to have long, high-aspect ratio wings with winglets (more and more of them). But, given the huge range of speeds they need to fly, the requirement to store lots of fuel, handle very heavy wingloading, etc, there are a range of compromises required. Sweep angle for high mach numbers, accomodating tons of lift augmenting devices (slats, fowler flaps), fuel tanks, etc. are all things that glider manufacturers don't have to worry about.

On Monday, October 22, 2012 9:11:38 AM UTC-4, 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