Aero-Efficient Shapes: Investigating Why

[Srinand]

This is an my topic for my essay. I'd like it if people can post up some theories to this topic. I am investigating why is it that commercial planes have a round nose whereas most fighter planes have sharp noses (Like the beaks of birds) and why F1 cars cars have a conical nose cone instead of a sharp one as they are required to go fast and also, why is it that submarines (designed aerodynamically for smooth and efficient and fast movement under the sea) always have round noses (since water is just a denser medium than air). Can you guys please post up any theories you think? It can be really complicated, no probs.

 

[3trQN]

I think it is mostly due to the velocities that they fly at. Fighter planes fly at supersonic speeds where the air compresses and a pointy nose becomes more efficient. Like a ship cutting through the water.

Concorde had a pointy one.

 

[Astronuc]

Commercial aircraft fly sub-sonic, while some military aircraft do go supersonic. Look at subsonic military craft and they probably have round noses.

Submarines travel a lot slower (~ 60 km/hr) than aircraft (~800-900 km/h).

Even the space shuttle has a round nose.

It's a tradeoff between drag and cross-sectional area. The curved surfaces are optimized for the cruise velocity (and laminar flow - minimal turbulence) to minimize momentum and energy transfer to the fluid.