Contrary to common belief, airplanes aren’t designed with stiff and rigid wings; they are designed with flexible wings.
When flying at cruising altitude, airplanes are exposed to significant stress. The wings must be able to withstand the stress. Otherwise, the wings may fail, which will affect the airplane’s ability to generate lift and maintain flight level.
Wing Flexing: What You Should Know
It’s completely normal for an airplane’s wings to flex during flight. The Boeing 787’s wings, for instance, can flex as much as 26 feet, whereas the Airbus A350’s wings can flex as much as 17 feet. Even smaller airplanes are susceptible to wing flexing — but to a lesser extent than the Boeing 787 and the Airbus A360.
At cruising altitude, the wings will flex upward. This is the result of their lift-generating properties. The wings are the primary lift-generating surfaces on an airplane. As air moves over and under an airplane’s wings, the difference in pressure creates lift. Lift literally pulls or lifts airplanes during flight. Because lift is an upwards force, it causes the wings to flex upwards.
Understanding Why Wings Flex
Airplane wings flex for several reasons, one of which is protection from stress-related damage. Rigid wings are more susceptible to damage during flight. They may crack or otherwise fail when exposed to structural stress. Flexible wings, though, are able to bend and flex in response to structural stress, which protects them from such damage.
Flexible wings also improved fuel efficiency. With flexible wings, airplanes can achieve the most aerodynamic shape, thereby reducing drag and improving fuel efficiency.
Factors That Affect Wing Flexing
The size of an airplane will affect how much its wings flex. As previously mentioned, larger airplanes like the 787 and A350 typically have more flexible wings than smaller airplanes.
The material or materials from which an airplane’s wings are made will affect how much they flex. In the past, airplanes were made of rigid materials that offered little or no flexibility. Today, however, airplanes are made of advanced materials like carbon fiber that provide a unique combination of strength and flexibility
The altitude at which airplanes fly will affect how much their wings flex. Flexing is typically greater at low altitudes than high altitudes. The air is denser at low altitudes, resulting in more lift and resistance.
Weather can affect how much an airplane’s wings flex during flight. Turbulence, for example, can cause sudden flexing. It will expose the airplane’s wings to significant resistance — typically for a short period — causing the wings to flex.
