Calculating the approximate top speed of a vehicle is straightforward.
$v = \sqrt[3]{\frac{2P}{c \cdot D \cdot A}}$
where
- v = velocity of the vehicle
- P = power of the engine
- c = coefficient of friction
- D = density of the air
- A = the area of the front of the vehicle
Using this equation you can get a rough idea of the top speed of a car if you know its engine power, the body’s coefficient of friction and the area of its front profile.
Is it possible to use this same equation to determine an approximate top speed for subsonic aircraft? No doubt engineers at Boeing have to account for 100 additional variables, but is it good enough to produce a decent approximation for props that fly less than 500mph?
Also does the picture I attached below show the correct way to account for variables $A$ and $c$?
If $c$ represents the friction along the entire surface of the aircraft does this suggest that all things being equal an aircraft with twice the surface area would have twice the coefficient of friction? Or am I looking at $c$ incorrectly?