Which kind of wing typically has a higher critical Mach number?

A sweptback wing typically has a higher critical Mach number due to its aerodynamic design that delays shock wave formation. When an aircraft approaches the speed of sound, shock waves can form on the wings, which can lead to a loss of lift and increase drag, negatively impacting performance.

Sweptback wings are angled backward from the fuselage. This design effectively alters the airflow over the wing, allowing the aircraft to fly faster before reaching the conditions that lead to compressibility effects. The rearward angle of a sweptback wing causes the airflow to be directed over a longer path, which can help to preserve lift at higher speeds. This characteristic makes sweptback wings ideal for high-speed flight, as they naturally mitigate the onset of wave drag compared to straight wings.

In contrast, straight wings have a lower critical Mach number because they reach compressibility effects sooner as their design does not delay shock wave formation effectively. Delta wings, while they do perform well at high speeds, are optimized for specific maneuvers and may not inherently possess a higher critical Mach number than swept wings. Canard wings, being smaller and more control-oriented, also do not match the attributes that contribute to higher critical Mach numbers in their design.