Nozzles are used in conjunction with almost all reaction engines. Vehicles using nozzles include jet aircraft, rockets and personal watercraft. While most nozzles take the shape of a cone or bell, some unorthodox designs have been created such as the aerospike. Some nozzles are intangible, such as the electromagnetic field nozzle of a vectored ion thruster.Continuous track is sometimes used instead of wheels to power land vehicles. Continuous track has the advantages of a larger contact area, easy repairs on small damage, and high maneuverability. Examples of vehicles using continuous track are tanks, snowmobiles and excavators. Two continuous tracks used together allow for steering. The largest vehicle in the world, the Bagger 288, is propelled by continuous tracks. Propellers (as well as screws, fans and rotors) are used to move through a fluid. Propellers have been used as toys since ancient times, however it was Leonardo da Vinci who devised what was one of the earliest propeller driven vehicles, the "aerial-screw". In 1661, Toogood & Hays adopted the screw for use as a ship propeller. Since then, the propeller has been tested on many terrestrial vehicles, including the Schienenzeppelin train and numerous cars. In modern times, propellers are most prevalent on watercraft and aircraft, as well as some amphibious vehicles such as hovercraft and ground-effect vehicles.
Systems employing elastic materials suffer from hysteresis, and metal springs are too dense to be useful in many cases.Flywheels store energy in a spinning mass. Because a light and fast rotor is energetically favorable, flywheels can pose a significant safety hazard. Moreover, flywheels leak energy fairly quickly and affect a vehicles steering through the gyroscopic effect. They have been used experimentally in gyrobuses. Wind energy is used by sailboats and land yachts as the primary source of energy. It is very cheap and fairly easy to use, the main issues being dependence on weather and upwind performance. Balloons also rely on the wind to move horizontally. Aircraft flying in the jet stream may get a boost from high altitude winds. Compressed gas is currently an experimental method of storing energy. In this case, compressed gas is simply stored in a tank and released when necessary. Like elastics, they have hysteresis losses when gas heats up during compression. Gravitational potential energy is a form of energy used in gliders, skis, bobsleds and numerous other vehicles that go down hill. Regenerative braking is an example of capturing kinetic energy where the brakes of a vehicle are augmented with a generator or other means of extracting energy. Motors and engines
When needed, the energy is taken from the source and consumed by one or more motors or engines. Sometimes there is an intermediate medium, such as the batteries of a diesel submarine.Most motor vehicles have internal combustion engines. They are fairly cheap, easy to maintain, reliable, safe and small.