A more fuel-efficient airplane design

The Wright brothers only made progress in powered flight when they stopped trying to mimic birds and started their design work from a clean sheet of paper. Now, the opposite approach may be the means through which designers realize more fuel-efficient planes.

A tailless concept. Credit: RJ Huyssen/NU,RSA

So say researchers Geoffrey Spedding, an engineer at the University of Southern California, and Joachim Huyssen at Northwest University in South Africa. Speaking at the American Physical Society Division of Fluid Dynamics meeting in Long Beach, the two say the dominant aircraft configuration, often known as tube-and-wings, could have established itself because it is simply good enough and has become entrenched in practice. By contrast, tailless designs have been tried throughout aviation's history but have rarely succeeded in displacing the tube-and-wing.

The two propose a new configuration may be aerodynamically superior to the status quo and thus more fuel efficient. They describe wind tunnel tests in which the cases wing-alone, wing/body, wing/body/tail were compared for the spanwise downwash distribution in their wake. Based on these measurements, they suggest a different configuration where the primary function of the tail is circulation control over the wing and body. This configuration bears more than a passing resemblance to certain birds.

The gull-wing concept. Credit: RJ Huyssen/NU,RSA

The tail in a conventional airplane controls pitch, i.e. whether the nose points up or down. In contrast, researchers use the wings in the new design to control pitch. To control pitch stability, they also gave the wings a slight crook for what they call a gull wing configuration. They say this feature eliminates the need for a conventional tail and, in turn, the need for the elongated tube body of a conventional aircraft.

An abstract for the paper can be found here: http://meetings.aps.org/Meeting/DFD10/Event/132371