- Joined
- Sep 6, 2007
- Messages
- 3,297
- Reaction score
- 2,288
Professor Qiqi Wang is part of a team that has shown that a bi-plane – essentially two, stacked wings - could bring huge improvements over the traditional delta-wing seen on Concorde. The idea was first proposed by German engineer Adolf Busemann, an influential aerospace designer who among other things first proposed the use of ceramic tiles to protect the Space Shuttle on reentry. According to theory, the Busemann bi-plane, when travelling at supersonic speeds, should produce less drag meaning it should use less fuel. Plus, the triangular wings can be “tuned” so that sonic boom is almost entirely eliminated.
“When we have two wings, if we place them in a carefully designed manner, the shockwaves from the two wings can cancel each other” says Prof. Wang.
However, the design has a major limitation for a plane – it lacks lift. The two wings create a narrow channel that limits the amount of air that can flow between them. When the plane accelerates through the sound barrier it becomes “choked” with air, causing an incredible amount of drag - much larger than a traditional Concorde-like design. This effectively means that a supersonic bi-plane works beautifully on paper, it could never reach supersonic speeds in the first place. Not only that, but the sonic-boom cancellation only works at a specific speed. If you are not at that exact speed, you don’t get the desired effect.
Shape shifters
To address these problems Wang turned to computer modeling to come up with an optimum wing shape for different speeds. The researchers then crunched through the 700 different shapes to produce an optimal configuration that would work at all speeds. Amongst the design tweaks they came up with were a smoothed inner surface for each wing to help air flow. The overall result is a wing that could fly at supersonic speeds, with half the drag of Concorde; something that could significantly cut fuel use.
Whilst it sounds like Wang and his team have cracked the problem, there is still a long way to go. So far, Wang has only shown the bi-wing concept working in two dimensions. Scaling this up to a three-dimensional prototype is more of a challenge. And expanding wing design to plane design, and getting everything to work together will be harder still.
“We are experts in designing components, and we are experts in designing something for a specific condition” says Duraisamy, who was not involved in the MIT work. In a supersonic aircraft though, nothing is constant. The conditions at take-off and landing are very different to the conditions at cruising speed. The plane encounters a whole range of possibilities, from different temperatures to different air densities.
“When we have two wings, if we place them in a carefully designed manner, the shockwaves from the two wings can cancel each other” says Prof. Wang.
However, the design has a major limitation for a plane – it lacks lift. The two wings create a narrow channel that limits the amount of air that can flow between them. When the plane accelerates through the sound barrier it becomes “choked” with air, causing an incredible amount of drag - much larger than a traditional Concorde-like design. This effectively means that a supersonic bi-plane works beautifully on paper, it could never reach supersonic speeds in the first place. Not only that, but the sonic-boom cancellation only works at a specific speed. If you are not at that exact speed, you don’t get the desired effect.
Shape shifters
To address these problems Wang turned to computer modeling to come up with an optimum wing shape for different speeds. The researchers then crunched through the 700 different shapes to produce an optimal configuration that would work at all speeds. Amongst the design tweaks they came up with were a smoothed inner surface for each wing to help air flow. The overall result is a wing that could fly at supersonic speeds, with half the drag of Concorde; something that could significantly cut fuel use.
Whilst it sounds like Wang and his team have cracked the problem, there is still a long way to go. So far, Wang has only shown the bi-wing concept working in two dimensions. Scaling this up to a three-dimensional prototype is more of a challenge. And expanding wing design to plane design, and getting everything to work together will be harder still.
“We are experts in designing components, and we are experts in designing something for a specific condition” says Duraisamy, who was not involved in the MIT work. In a supersonic aircraft though, nothing is constant. The conditions at take-off and landing are very different to the conditions at cruising speed. The plane encounters a whole range of possibilities, from different temperatures to different air densities.
