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I looked up glide ratios of passenger jets in the past and was surprised at the variability of answers. The 12-16:1 range comes up most frequently, but also some references as low as 3-4:1 (especially when flown "heavy") and also as high as 28:1 for an MD-80 on one website. Wow, really, 28:1?!


As with anything the lift to drag ratio is a variable for any aircraft, which depends on the Altitude, glide speed, payload etc.

The LD ratio is proportional to the square root of the wing aspect ratio divided by the zero lift drag coefficient. So just by looking at an aircraft such as the Boeing dreamliner or DH Comet 4, they will have an excellent LD ratio because of high aspect ratio wing. Aspect ratio is equal to the square of the wing span divided by the wing planform area. So aircraft with long narrow wings will have the greatest LD or glide ratio.

Concorde for example will have a glide ratio of between 4 and 7 depending on its speed and altitude due to the supersonic capable small aspect wing ratio and large overall wing area making it the fastest jet aircraft in the world including all in service types including all civilian or military types.