Why Can't Airplanes Just Flap Their Wings Like Birds?

In theory, it is possible to build an airplane with flapping wings, but the mechanical systems required for this would be complicated and very heavy. The resulting aircraft would be inefficient and slow. This concept was even attempted in the early days of aviation but never succeeded due to significant technical challenges.

The Evolution of Aviation

For the past 100 years, flapping wings were replaced with propellers and turbine blades. These innovations, often referred to as "flappers," have revolutionized aviation. However, if you haven’t kept up with the developments in this field, it might seem that airplanes should still flap their wings like birds. In reality, there are fundamental reasons why modern aircraft don’t use flapping wings.

Modern Airplane Flaps and Their Functions

Most modern airplanes do have flaps, although pilots typically refer to them as "using their flaps" or "extending and retracting their flaps." These flaps, which can be moved from zero to forty degrees, serve various purposes:

Boosting Lift on Take-Off: Partial flaps up to about 20 degrees provide more lift for take-off.

Increasing Drag for Slower Landings: Partial flaps above 20 degrees and full-down flaps increase drag, leading to slower landing speeds and a faster descent.

Emergency Descent: Pilots can also use a technique called "slipping" for a faster descent to a landing.

The Inefficiency of Flapping Wings in Airplanes

It is important to understand why airplanes do not flap their wings. Birds flap their wings because they need to generate thrust to move forward. In contrast, airplanes use jet engines to generate thrust. Flapping wings in a plane would be highly inefficient. It would require a significant amount of energy to move the wings, potentially even more than the engines can provide. Furthermore, flapping wings would increase the complexity and weight of the aircraft, leading to inefficiencies in both performance and fuel consumption.

Design Choices in Aviation

Modern commercial jets are designed with a balance of glide and maneuverability, inspired more by the gliding characteristics of hawks and other birds. During takeoff and climbing, hawks do flap their wings, but they primarily use their wingspan to glide on the air currents. Airplanes, on the other hand, have fixed wings and rely on jet engines for thrust, just as a hawk has gliding wings and a hawk-like body for lift and maneuverability.

In conclusion, while the idea of airplanes flapping their wings might seem intriguing, it is not practical or efficient. Instead, modern aviation has adopted a hybrid design that combines the best aspects of both bird flight and jet engines to create the marvels of contemporary commercial aircraft.