A new take on carving: the Dynamically Augmenting Wheel System
By David Greig
March 13, 2009
March 13, 2009 The notion of “carving” to improve a vehicle's handling whilst negotiating a corner is not new but this concept design from Charles Pyott known as the Dynamically Augmenting Wheel System, or simply DAWS, takes the idea in a new direction by changing the shape of the actual wheel to achieve its objectives.
The principal of carving in the motor industry can be explained simply as placing the wheels and/or the center of gravity of the vehicle in such a position as to counteract the centrifugal (outward) force generated from the turn, thus improving the '.
An example of the effectiveness of being able to change the vehicle's center of gravity to counteract the outward forces generated whilst in a sharp turn, comes from a comparison of a car versus the motorcycle. A relatively flat car tire offers plenty of traction due to the large surface area in contact with the road surface. However when the conventional car turns sharply it can’t alter its center of gravity to counteract the outward force and it tends to loose traction and slide. A motorcycle however, with its rounded tires, allows for leaning into the corner and more effectively counteracting the outward force.
We have seen many three and four wheel vehicles in recent years that use the principals of carving to improve handling during cornering. These include Hybrid carving 3 wheeler which allows the body to tilt whilst cornering, Piaggos carving three-wheel bike which features two independently suspended tilting front wheels and the Mercedes F400 carving system which includes active wheel camber control and even a four wheeled carving recumbent bike.
And now along comes the DAWS, which takes a radically different approach to achieve its end by altering the shape of the wheel.
Designer Charles Pyott’s set out to create a wheel system that would facilitate a shift in center of gravity without a loss of traction. His DAWS concept achieves this by having the wheel featuring eight independent segments that are guided in a lateral direction on a liner bearing at the hub - sort of like taking to the wheel with a pizza slicer. The idea is to enable the whole vehicle to shift and maintain traction without decreasing tire footprint area in contact with the road. In summary
Having a vehicle that can carve or tilt into a corner makes good sense. However the prospect of all the moving parts within the DAWS system and the resulting load on the wheel during cornering, may prove to create some real challenges in the engineering prototype phase. We wish them well!