What advantage does a sweptback wing have compared to a straight wing?

A sweptback wing is designed to enhance the aerodynamic properties of an aircraft, particularly at high speeds. The primary advantage of a sweptback wing compared to a straight wing is its ability to achieve a higher critical Mach number.

The critical Mach number is the speed at which airflow over any part of the wing reaches the speed of sound. As a wing becomes swept, the effective angle at which the airflow meets the wing reduces, resulting in a lower likelihood of shock waves forming at subsonic speeds. This design advantage enables sweptback wings to maintain stable flight at higher speeds before encountering transonic effects, such as drag increases and loss of control.

This aerodynamic efficiency at elevated speeds is particularly beneficial for jet aircraft, which often operate close to or beyond the speed regimes where straight wings would face limitations. The sweptback wing structure allows for smoother airflow, thereby delaying the onset of compressibility effects, leading to improved performance in high-speed flight.