Originally Posted by
Bahamasflyer
Just watched the launch of SpaceX and it got me wondering? What altitude does one have to reach in order for mach # to become meaningless? Is it a sudden thing, or gradual?
Max Q is probably the most import factor.
The max q condition is the point when an aerospace vehicle's atmospheric flight reaches maximum dynamic pressure. This is a significant factor in the design of such vehicles because the aerodynamic structural load on them is proportional to dynamic pressure. This may impose limits on the vehicle's flight envelope.