Wikipedysta:Leafnode/Brudnopis
Z Wikipedii, wolnej encyclopedia
In aerospace engineering, max Q is the point of maximum dynamic pressure, the point at which aerodynamic stress on a spacecraft in atmospheric flight is maximized.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Apollo_11_launch.jpg/640px-Apollo_11_launch.jpg)
Considering the definition of dynamic pressure: , we have that such quantity:
- is zero at lift-off, when the vehicle's speed
- is zero outside the atmosphere, where the air density
- is always positive (or zero, as above) given the quantities involved
Therefore there will be necessarily a point where the dynamic pressure is maximum: that point is precisely max Q.
In other words, below the max Q point, the effect of the spacecraft acceleration overcomes the decrease in density. Above the max Q point, the opposite is true.
During a normal Space Shuttle launch, for example, max Q is at an altitude of around 11 km (35,000 ft).[1] During a typical Apollo mission, max Q occurred approximately between 13 km and 14 km of altitude (43,000 ft - 46,000 ft).[2][3]