Does AirPlane Wings Must be Curved to fly?

Question

What about the F-117 Nighthawk that never looks curvey.

Answer 1

In order to create lift, the upper surface of a wing must be longer than the lower surface. That's why wings are curved. The bottom is flat and the top is curved. The F-117 doesn't have a "curve", but the upper surface is shaped with flat plates so that the upper surface is longer than the lower surface. It's not as aeordynamic and efficient as a nice, smooth curve, but I'll take not being seen over efficiency any day in a war.

Answer 2

Ah, some of your answers leave a bit of question. By curved, I assume you mean the cross sectional shape of the wing. The principal of aerodynamic lift requires that the surface create a pressure difference between the upper and lower surfaces. At the same time, we would like to minimize drag. Drag has a strong dependence on the amount of turbulence generated.

Now, lets look at three possible wings, and perhaps that will answer your question. First, take a nice elongated teardrop shape for your wing. You have minimized drag with this shape, so you can fly efficiently. But, you must push this shape through the air with a positive 'angle of attack' in order for lift to be generated. To not have that angle, you make the shape flatter on the bottom.

Next, lets look at a flat plate. It will go through air without much resistance, but will generate no lift until you give it a positive angle of attack. It will then produce lift, but the amount of turbulence generated greatly increases drag. Not very efficient.

Now look at a wing like you have asked about. The surfaces are flat, but the cross section is much like a normal wing, just with the curved profiles replaced with straight lines. It will generate more drag than a normal wing, but the shape has been optimized to reduce that. To overcome it simply requires more power. For military applications, efficiency is not always the prime objective.

So the answer to your question, is no. You could get a brick to fly theoretically, with the right angle and enough power.

Answer 3

Flight occurs when lift exceeds drag and gravity. A curved wing provides natural lift by creating low pressure above the wing, sucking the plane upwards.
A flat wing can work, but the thrust must be constant and the wing functions not for lift production, but simply for guidance.
The F-117 is a modified lifting body ... the whole airframe provides some lift, and thewings provide very little. It also has very powerful engines that provide pleny of thrust.
It is also so unstable that it cannot fly without its "fly-by-wire" systems.
Cheers.

Answer 4

All the wing does on an aircraft is create down force or a downward flow of air sufficient to support the weight of the craft. The curved wing is the most efficient way to do this. In other words, the curved wing requires less thrust to give it the forward motion necessary to produce this down force. Military aircraft, particularly fighter types have excess power to overcome the many inefficiencies that may be built in to make the unit more maneuverable or more invisible or whatever.