Max Q

src: www.notebookcheck.net

In aerospace techniques, maximum dynamic pressure , often referred to as the maximum Q or max Q , is the point at which aerodynamic pressure on the vehicle in the flight of the atmosphere is maximized. This is an important factor in the structural design and mission of rockets, missiles, and other aerospace vehicles traveling through the atmosphere; flight envelopes may be limited to reduce the total structural load on vehicles near max Q.

Tekanan dinamis, q , didefinisikan secara matematis sebagai

${\ displaystyle q = {\ tfrac {1} {2}} \, \ rho \, v ^ {2},}  ÂÂ$

where ? is the local air density, and v is the speed of the vehicle; dynamic pressure can be considered as the density of the kinetic energy of air to the vehicle. For rocket launch from the ground into space, dynamic pressure

• zero at launch, when air density ? high but vehicle speed v = 0
• zero outside the atmosphere, where speed is v high, but the air density ? = 0
• is always not negative, considering the number involved

Therefore, (with Rolle's theorem) there will always be a point where maximum dynamic pressure. The point where that happens is max. Q.

In other words, before reaching max Q, dynamic pressure changes due to increased speed is greater than that because of the decrease in air density so that the dynamic pressure (opposing kinetic energy) acting on the plane keeps increasing. After passing max Q, the opposite is true. The dynamic pressure acting against the plane decreases as the air density decreases, eventually reaching 0 when the air density becomes zero.

Video Max Q

Examples of rocket launch

During normal Space Shuttle launches, for example, Q max occurs at an altitude of about 11 km (35,000 feet). Three Shuttle Main Machines are revived around 60-70% of rated thrust (depending on payload) when dynamic pressure approaches Q max; combined with the propellant perforation design of a solid rocket booster, which reduces the thrust at max Q to a third after 50 seconds of burning, the total pressure on the vehicle remains at a safe level.

During a typical Apollo mission, max Q occurs between 13 and 14 km in height (43,000-46,000 ft); the same value occurs for SpaceX Falcon 9.

The max Q point is a major milestone during the rocket launch, as this is the point at which the fuselage is subjected to maximum mechanical stress.

Maps Max Q

See also

• Prandtl-Glauert singularity
• The ideal gas law

src: www.laptopmag.com

References

Source of the article : Wikipedia