At subsonic speeds, blunt noses - both fuselage and airfoil - are good for two reasons:
- the need to maintain attached flow at varying angles of attack.
- it has less surface area for the volume, reducing skin friction.
TOP: 0 AoA/Cruise | BOTTOM: extreme AoA, 20-30degrees, takeoff/landing
If the airflow had to flow over a ridge/point in scenario 2, instead of the smooth curve, flow separation would be more likely.
But things don't seem to add up.
Firstly, it's not like most airplanes - particularly airliners - fly at AoA beyond 20-30 degrees. At least not without high-lift devices. Am I correct? But on the rounded nose, there are surfaces smoothly curving all the way from 90 degrees! This seems to me like a useless increase in cruise drag.
Secondly, why push a blunt face ahead of you just to increase the volume a little, whem you can use a curve terminating at a point/ridge, as will be demonstrated below? If the surface area to volume ratio becomes so important, we can just sacrifice the fineness ratio and still have less drag, as the new nose creates less drag, right?
Would limiting the curvature to the max AoA limit for the aircraft, then terminating at a point, as in the image below, not keep the flow attached throughout the expected AoA range, while producing less drag? At the maximum AoA, the flow over the top of the shape encounters no "ridge" or "point", as it is parallel to the half-angle at the nose.
TOP: less drag is created at cruise | BOTTOM: Flow remains attached at extreme AoA conditions.
What am I missing about the sharp nose? How and how much does it hurt performance? Why, after all this seemingly shown in the question, is it - aside from the radar - that big planes have round noses?
In short: I am claiming that an elliptical nose tipped with a triangle or cone of 20-30 degrees half-angle should be better than a pure ellipse for subsonic aircraft. Why am I wrong?