12.10.2010, 10:21
That is a very difficult question to answer in general. It depends strongly on the shape of the object, the propelling force, air temperature+pressure, if you go uphill/downhill etc. For a sphere, you have a friction coefficient of 0.47 while for seemingly similar shapes it's different:
http://en.wikipedia.org/wiki/Drag_coefficient
The force and, hence, the maximum speed can then be calculated using the drag equation,
http://en.wikipedia.org/wiki/Drag_equation
This, however, is only true if you have the case of laminar airflow where drag grows with the square of the speed. If it becomes turbulent (as in the case of a wing ripped off), the force increases drastically, proportional to higher orders of the speed and, therefore, the maximum airspeed is lowered.
So, you see, while it's quite easy to predict the maximum speed of a sphere in laminar airflow, it becomes very difficult if you look at, e.g., a human being or even a "well-behaved" plane shape.
http://en.wikipedia.org/wiki/Drag_coefficient
The force and, hence, the maximum speed can then be calculated using the drag equation,
http://en.wikipedia.org/wiki/Drag_equation
This, however, is only true if you have the case of laminar airflow where drag grows with the square of the speed. If it becomes turbulent (as in the case of a wing ripped off), the force increases drastically, proportional to higher orders of the speed and, therefore, the maximum airspeed is lowered.
So, you see, while it's quite easy to predict the maximum speed of a sphere in laminar airflow, it becomes very difficult if you look at, e.g., a human being or even a "well-behaved" plane shape.