Should airplanes look like birds? Engineers envision more fuel-efficient design

The modern airplane design works well, but from a fuel efficiency standpoint, could planes be designed more aerodynamically -- to lower drag and increase lift? Geoffrey Spedding, an engineer at the University of Southern California, and Joachim Huyssen at Northwest University in South Africa, felt they could in theory, but they lacked experimental evidence. Now they have it.

Spedding and Huyssen have made a simple modular aircraft in three configurations: a flying wing alone, then wings plus body, and then wings plus body and a tail. It turns out that they had independently re-designed a bird shape, but without specific reference to anything bird-like. They will present their experimental data with these three designs, today at the American Physical Society Division of Fluid Dynamics meeting in Long Beach, CA.

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The modern airplane design works well, but from a fuel efficiency standpoint, could planes be designed more aerodynamically -- to lower drag and increase lift? Credit: RJ Huyssen/NU,RSA

The flying wings alone provide an ideal (but impractical) baseline, since it's hard to carry people or cargo in such a shape. The presence of a body, unfortunately, immediately lowers the lift and increases the drag. The addition of just the right kind of tail, however, can restore the lift, and reduce the drag, occasionally to nearly wing-only levels.

A few years ago a glider with the modest tail design was successfully test flown, but larger and commercial test prototypes have not yet been tried. Spedding recognizes that the design of real planes is necessarily a compromise of many engineering, economic and psychological constraints. Nevertheless, he believes much can be done to make planes more energy efficient in the future.

"The most important point is that we may be wasting large amounts of fossil fuel by flying in fundamentally sub-optimal aircraft designs," says Spedding. "At the very least, we can show that there exists an alternative design that is aerodynamically superior. One may argue that there is now an imperative to further explore this (and perhaps other) designs that could make a significant difference to our global energy consumption patterns."

More information: The presentation, "Should planes look like birds?" is on Sunday, November 21, 2010. Abstract: http://meetings.ap … Event/132371

Provided by American Institute of Physics