What makes a plane blunt?

Answer 1

If the plane is a wood plane and one is looking at the blade, the continuous shaving of the material being planed will eventually remove the tiniest bits of metal (or ceramic, if one has a plane blade that exotic - though they lack practicality). The removal of bits of the blade in the plane will leave a less-than-sharp edge, and it becomes less effective in removing material. It is said to be dull or blunt. Just about any cutting edge, whether on a kitchen knive or a machine tool, suffers the same fate. Even diamond (as a cutting material) dulls eventually. For an airplane, the plane will be blunt if it is less than aerodynamic. We (almost) always try for "smoother" and "cleaner" shapes and lines on airplanes for the obvious reason of reducing drag. (And it's plain why we do that.) Sometimes, though, we end up with a "blunt" design. The space shuttle would be a great example. It's got a big, fat nose, and it's been compared to a flying brick. It could be said to be very blunt when compared to, say, the X-15, the F-104 Starfighter, or even the F-117 Nighthawk.