Homebuilt Aircraft - Overview

Overview

In the United States, Brazil, Australia and New Zealand, homebuilt aircraft may be licensed Experimental under FAA or similar local regulations. With some limitations, the builder(s) of the aircraft must have done it for their own education and recreation rather than for profit. In the US, the primary builder can also apply for a repairman's certificate for that airframe. The repairman's certificate allows the holder to perform and sign off on most of the maintenance, repairs, and inspections themselves.

Alberto Santos-Dumont was the first to offer for free construction plans, publishing drawings of its Demoiselle in the June 1910 edition of Popular Mechanics. The first aircraft to be offered for sale as plans, rather than a completed airframe, was the Baby Ace in the late 1920s.

Homebuilt aircraft gained in popularity in the US in 1924 with the start of the National Air Races, held in Dayton, Ohio. These races required aircraft with useful loads of 150 lb (68 kg) and engines of 80 cubic inches or less and as a consequence of the class limitations most were amateur-built. The years after Charles Lindbergh's transatlantic flight brought a peak of interest between 1929 and 1933. During this period many aircraft designers, builders and pilots were self taught and the high accident rate brought public condemnation and increasing regulation to amateur-building. The resulting federal standards on design, engineering, stress analysis, use of aircraft-quality hardware and testing of aircraft brought an end to amateur building except in some specialized areas, such as racing. In 1946 Goodyear restarted the National Air Races, including a class for aircraft powered by 200 cubic inch and smaller engines. The midget racer class spread nationally in the US and this led to calls for acceptable standards to allow recreational use of amateur-built aircraft. By the mid-1950s both the US and Canada once again allowed amateur-built aircraft to specified standards and limitations.

Homebuilt aircraft are generally small, one to four-seat sportsplanes which employ simple methods of construction. Fabric-covered wood or metal frames and plywood are common in the aircraft structure, but increasingly, fiberglass and other composites as well as full aluminum construction techniques are being used, first pioneered by Hugo Junkers as far back as the late World War I era. Engines are most often the same as, or similar to, the engines used in certified aircraft (such as Lycoming, Continental, Rotax, and Jabiru). A minority of homebuilts use converted automobile engines, with Volkswagen air-cooled flat-4s, Subaru-based liquid-cooled engines, Mazda Wankel and Chevrolet Corvair six-cylinder engines being common. The use of automotive engines helps to reduce costs, but many builders prefer dedicated aircraft engines, which are perceived to have better performance and reliability. Other engines that have been used include chainsaw and motorcycle engines.

A combination of cost and litigation, especially in the mid-1980s era, which has discouraged general aviation manufacturers from introducing new designs, has led to homebuilts outselling factory types by five to one. In 2003, the number of homebuilts produced in the USA exceeded the number produced by any single certified manufacturer.