Design and construction of a wing-sail land vehicle

Abstract

A land yacht is a three or four wheeled vehicle which makes use of a sail or a rigid wing to convert the energy of the wind in driving force. A land yacht can carry one or two persons and is usually driven on sand or tarmac. Land yachts employing sails are very popular whereas those using rigid wings are still in the prototype phase, being continuously experimented and improved in an effort to match the performance obtained by the sail driven vehicles. Rigid wing land yachts have major drawbacks when compared to sail driven ones which probably account for their unpopularity. Being more complex to construct, they are more expensive. Moreover, being rigid, the wing is prone to serious damage should the land yacht topple. A fully blown sail indicates that the sail-wind direction relationship is optimal in the case of a sail driven land yacht. However to set the wing at the optimum angle of attack, requires sophisticated equipment that few sportsmen would be willing to buy. Also if a sail equipped land yacht is caught by a crosswing which threatens to topple it, all the driver has to do is lower the sail. This is obviously impossible with rigid wings. Transportation of the land yacht also presents problems as a very large area sail can be easily folded and packed away whereas a rigid wing has to be transported full size in one piece. The above are but few of the cons being encountered by rigid wing land yachts. However the satisfaction obtained from having designed and constructed such a vehicle more than outweights these problems. Certain parameters in the design of this vehicle had to be intelligently guessed after theory was consulted and after discussing the matter with our tutor. This had to be done since, any aerodynamic data available did not exactly apply to the type and shape of aerofoil used. The first chapter of the project deals with the relevant theory and some definitions of the literature usually used in conjunction with aerofoils. The construction procedure and the machining processes used to produce the various parts of the vehicle are explained in detail in chapter three. Finally, chapter four contains a detailed description of the heat treatment and the copper plating processes carried out on the rear wheel shafts.