Supersonic jets and their life expectancy suffered after the grounding of Concorde.
(Credit: Tohoku University/MIT)
Although this type of transport reached various destinations in record time, economic factors resulted in the permanent grounding of such craft. Limited seats, expensive tickets and extremely high fuel consumption all contributed to a type of transport that was simply not financially or commercially viable.
Since Concordes were taken from the sky in 2003, researchers have attempted to develop a more sustainable model for supersonic travel — quieter, cheaper and more efficient alternatives to previous supersonic jet models. The Massachusetts Institute of Technology (MIT) may have discovered such an alternative.
According to Qiqi Wang, an assistant professor of aeronautics and astronautics at MIT, a redesigned flight model may be the answer to increasing efficiency and lowering fuel consumption to the point that a future carrier could be an efficient and commercial means of travel.
The idea is simple: instead of one wing per side, why not use two?
Wang and his colleagues Rui Hu, a post-doctorate in the Department of Aeronautics and Astronautics, and Antony Jameson, a professor of engineering at Stanford University, have showcased their design through a computer model of the modified biplane.
By decreasing drag through the modified design of a dual-winged plane, there would be a significant reduction in fuel requirements. Not only this, but the plane would produce far less of a sonic boom — resulting in a quieter transport.
The MIT team are not the first to consider such a design. In the 1950s, a German engineer called Adolf Busemann saw the potential in this kind of biplane design. By studying the way that air becomes compressed once an aircraft approaches the speed of sound, resulting in an increase in pressure that causes a sonic boom, the engineer calculated that certain kinds of configuration could remove these shock waves.
"The sonic boom is really the shock waves created by the supersonic aeroplanes, propagated to the ground," Wang said. "It's like hearing gunfire. It's so annoying that supersonic jets were not allowed to fly over land."
The new designs produced by the researchers give these original ideas credence — which although cancelled out shock waves by positioning jets with wings positioned above each other rather than remaining on separate sides, unfortunately lacked the required lift.
A very narrow channel resulted from the wing positioning in the original designs, leaving only a limited amount of available airflow — causing increased drag at the high speeds required to reach a supersonic level.
However, with Wang's design based on a computational model, optimal wing shapes could be calculated to remove this issue. Over a dozen different speeds and 700 wing configurations were analysed to achieve the "optimal" shape for each wing — something that Busemann had no access to.
By smoothing the inner surfaces of each wing to create wider airflow channels, and by bumping out the top edge of each "higher" wing, not only could the lift issue be solved, but theoretically the craft could achieve supersonic speeds — with a substantial drop in the drag levels that supersonic jets had to endure.
Wang says that this kind of design could also result in fuel consumption reductions of over 50 per cent for high-speed aircraft in the future. In addition, the possibility of lowering the capacity of fuel storage required could also invoke a chain reaction in reducing drag — by limiting the size requirements of a carrier.
The results will be published in the Journal of Aircraft. The team plan to further their work by developing a 3D model in the future, in order to address other issues that can affect a craft's flight functionality.
"Now people are having more ideas on how to improve [Busemann's] design," Wang concluded. "This may lead to a dramatic improvement, and there may be a boom in the field in the coming years."