For today’s #askextremeross, I’m taking the question from @impaktech : What is the science between the skinny long wings and the ability to fly at high altitude.
This picture shows a pretty good silhouette of the wing taken from the back seat of a 2-seater above 60,000 feet (sun is directly behind the wing). Many people say the U-2 is like a big glider, and they’re not wrong. It’s just one with a really powerful engine. The key characteristic that makes gliders and U-2s so good at staying in the air is aspect ratio. The aspect ratio is the ratio between a wing’s span and it’s mean chord (layperson speak: ratio of length vs width). A long skinny wing has a high aspect ratio (gliders and U-2s). A short fat wing has a low aspect ratio (think fighter jet). High aspect essentially means more wing surface meeting the air to provide lift. It has great lift qualities but sacrifices speed and maneuverability. Those qualities are necessary to deflect the few air molecules up there to provide lift. But everything in aviation (just like most engineering) is about trade-offs. What do you need it to do and what are you willing to give up to make it happen. The U-2 just needs to fly as high as possible for as long as possible. We can’t go fast but we can get high and stay there a long time. I’ll have a more thorough blog about the U-2 aerodynamics at a future date.