Three wheeled car

A three wheeled car, also known as a tricar or tri-car, is an automobile having either one wheel in the front for steering and two at the rear for power, two in the front for steering and one in the rear for power, or any other combination of layouts.

History

Early car pioneer Karl Benz developed a number of three-wheeled models.cite web |url=http://pages.zoom.co.uk/elvis/history2.html |title=The History of the 3-Wheeled Vehicle |author=Elvis Payne |date=2001 |publisher=pages.zoom.co.uk |accessdate=2008-01-20] One of these, the Benz Patent Motorwagen, [cite web |url=http://star-motoring.com/news/story.asp?file=/2006/7/2/ms_features/14249260&sec=ms_features |title=History in its magnificence |author=Chris Chong |publisher=star-motoring.com |date=July 2 2006 |accessdate=2008-01-20] is widely regarded as the first purpose-built automobile,Fact|date=January 2008 and may be the first petrol car driven on British soil, in 1894. In 1896, John Henry Knight showed a tri-car, recognized as the first British-made motorcar, at The Great Exhibition. A Conti 6 hp Tri-car competed in (but did not complete) a 1907 Peking-to-Paris race sponsored by a French newspaper, "Le Matin". [cite web |url=http://www.pekingparisraid.co.uk/History/index.asp |title=History |publisher=pekingparisraid.co.uk |accessdate=2008-01-20]

trengths and weaknesses

Having one wheel in front and two in the rear for power reduces the cost of the steering mechanism, but greatly increases instability. However, a configuration of two wheels in the front and one wheel at the back has many strong proponents among automotive designers and enthusiasts. Two advantages are its improved aerodynamics, and that it readily enables small lightweight motorcycle powerplants and rear wheels to be used. This approach was used by the BMW Isetta.

For the lowest wind resistance (which increases fuel efficiency), a teardrop shape is desirable. A tear drop is wide and round at the front, tapering to a point at the back. The three wheel configuration allows the two front wheels to create the wide round surface of the vehicle. The single rear wheel allows the vehicle to taper at the back. This approach is used by the Aptera Typ-1.

Having one less wheel also increases fuel efficiency because of decreased rolling resistance.

The disadvantage of a non-tilting three wheel configuration is instability - the car will tip over in a turn before it will slide, unless the centre of mass is much closer to the ground or the wheelbase is much wider than a similar four wheel vehicle. To improve stability some three wheelers are designed as tilting three wheelers so that they lean while cornering like a motorcyclist would do. The tilt may be controlled manually or by computer. Electric three-wheelers often lower the center of gravity by placing the heavy battery pack at the base of the vehicle.

Examples

Registration

In at least some U.S. states, three-wheeled cars are regulated as motorcycles, with similar licensing requirements. In other jurisdictions, such as British Columbia, Canada, a three-wheeled vehicle with an enclosed passenger compartment is considered an automobile.

See also

*Three wheeler
*Tricycle - Motorized tricycles
*Tuk-tuk or Auto rickshaw - Three wheeled vehicles popular in many parts of Asia
*Steam tricycle
*Cushman - The only manufacturer of 3-wheeled autos in the United States, many built for utility/maintenance
*Tri-Magnum - a DIY three-wheeler

References

External links

* [http://www.3wheelers.com/history.html History of the Three Wheeler]
* [http://www.rqriley.com/3-wheel.htm "Three Wheel Cars; Primary Factors that Determine Handling & Rollover Characteristics"]
* [http://www.schultzengineering.us/ptv-rnd/research.htm Link index for three wheeled cars as well as other types]