Why do some aircraft have rounded nose while some have pointed nose?

Why do some aircraft have rounded nose while some have pointed nose?

Image from: - wikimedia

Take a look at any modern passenger aircraft. You will see almost all of them have rounded (blunt shaped) nose.

Take a look at some of these aircraft!

Airbus A380

Image from: - wikimedia

Boeing 747

Image from: - wikimedia

All of them are having rounded nose. And all are subsonic aircraft. (Speed less than speed of sound i.e. < 1 Mach)

Now take a look at these aircraft!

Concorde

Image from: - wikimedia

Tupolev TU 144

Image from: - wikimedia

These aircraft are having cone shaped nose. These cone shaped aircraft have a common thing among them. That's both are supersonic passenger aircraft. Supersonic aircraft are those which travel faster than speed of sound (i.e. > 1 Mach)

In a case of subsonic aircraft, most of aircraft have rounded nose. As aircraft travels with subsonic speed it pushes air molecules in front of it. And these air molecules starts moving and again pushes other air molecules infront of it. This creates pressure field in front of aircraft and indicates air molecules that aircraft is coming. So air molecules be ready for impact with aircraft without any production of shock.

But in a case of supersonic aircraft with rounded nose, speed of aircraft is so high that air molecules do not get any indication of coming aircraft. Aircraft suddenly impacts air molecules. This causes production of shock. This shock produces huge amount of drag. To reduce such type of drag, nose of supersonic aircraft are cone shaped. A pointed nose is more aerodynamic in supersonic flow.

This is the reason most of supersonic aircraft have pointed nose.

F22 Raptor

Image from: -wikimedia

F35 Lightning

Image from: - wikimedia

In case of subsonic aircraft with rounded nose, speed is not so high for production of shocks. Instead cone shaped nose at subsonic speed causes increase in skin friction drag.  Hence cone shaped nose is not used in subsonic aircraft. A shape with a round front is more aerodynamic in subsonic flow than a pointed nose.

Thanks for reading!

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