Kit Airplanes - Let Your Dreams Take Flight With Your Own Home Built Airplane.
Also known as homebuilt airplanes or kit airplanes, kit planes are constructed by persons for whom this is not a professional activity. These aircraft may be constructed from "scratch," from plans, or from assembly kits. There are a number of companies out there who specialize in homebuilt airplane kits. Some of the larger companies are Vans Aircraft, Lancair, Glasair Aviation, Murphy Aircraft Mfg, Mustang Aeronautics, Zenith Aircraft Company and Sonex Aircraft
In edition to the regular kit airplanes, there are also Light Sport Airplanes (LSA) that are available to be built. LSA's can be a whole lot less costly than a normal kit plane.
In the United States, Australia and New Zealand, kit airplanes may be licensed Experimental Aircraft under FAA or similar local regulations. Provided that the owner has done at least 51% of the construction work themselves. Recent amendments to the FAA regulations has changed this. The owner now has to fabricate, from scratch, a certain percentage of the airplane. My understanding is when you receive your kit plane package you will have all the necessary parts plus a sheet of sheet metal, for example, which you will have to use to fabricate the panel, for example.
The first aircraft to be offered for sale as plans, rather than a completed airframe, was the Baby Ace in the late 1920s.
Kit airplanes gained in popularity in the US during the 1950s with the formation of the Experimental Aircraft Association. During this time period there was also a large demand for light aircraft created by ex-military pilots who flew during World War II.
"Homebuilt airplanes 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. 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 kit airplanes 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." (Wikipedia)
A combination of cost and litigation, which has discouraged general aviation manufacturers from introducing new designs, has led to kit airplanes outselling factory types by five to one. In 2003, the number of kit airplanes put together in the USA exceeded the number produced by any single certified manufacturer. If you wish to build a brand new kit plane, and you only want an airplane with the bare bones, then you can achieve that for approximately $30,000 USD. Compare that to a brand new Cessna 172 at a starting price of approx $200,000USD and you can see why more and more people are building their own kit planes. There are many reasons people may want to build, many advantages, and many things to consider. Check out this excellent discussion on
the benefits of your own homebuilt aircraft project.
The history of experimental aviation can be traced to the invention of the airplane. Even if the Wright brothers, Clément Ader, and their successors had commercial objectives in mind, the first airplane invented. were constructed by passionate enthusiasts whose main goal was to fly with the birds.
Airplane technology took a huge leap forward with the start of the First World War and the subsequent demand for airplanes to do aerial recconnaisance and aerial sighting for the artillery. After World War 1, manufacturers needed to find new markets for their products, and introduced airplanes designed for tourism. However, these planes were affordable only by the very rich and the elite of society.
"Many U.S. aircraft designed and registered in the 1920s onward were considered "experimental" by the (then) CAA, the same registration under which modern kit airplanes are issued Special Airworthiness Certificates. Many of these were prototypes, but designs such as Bernard Pietenpol's first 1923 design were some of the first homebuilt aircraft. In 1928, Henri Mignet published plans for his HM-8, as did Pietenpol for his Air Camper. Pietenpol later constructed a factory, and in 1933 began creating and selling partially-constructed aircraft kits." (Wikipedia)
In 1946 the Ultralight Aircraft Association started up. In 1952 they became known as the Popular Flying Association in the United Kingdom, followed in 1953 by the Experimental Aircraft Association in the United States and the Sport Aircraft Association in Australia.
Technology and Innovation
Until the late 1950s, builders had mainly kept to wood-and-cloth and steel tube-and-cloth design. Without the regulatory restrictions faced by production aircraft manufacturers, homebuilders introduced innovative designs and construction techniques. Burt Rutan introduced the canard design to the homebuilding world and pioneered the use of composite construction. Metal construction in kit planes was taken to a new level by Richard VanGrunsven in his RV series. As the sophistication of the kit planes improved, components such as autopilots and more advanced navigation instruments became common. Today it is common to see home built aircraft with full glass cockpits complete with an autopilot system that is coupled to a GPS navigation system. This is the same technology that the major airlines use, albeit on a smaller scale.
Litigation during the 1970s and 1980s caused stagnation in the small aircraft market, forcing the surviving companies to retain older, proven designs. In recent years, the less restrictive regulations for kit airplanes allowed a number of manufacturers to develop new and innovative designs; many can outperform certified production aircraft in their class. Vans RV7, for example, will cruise at 210mph or 182kts with a 180HP engine)
An example of a high-end kit plane design is the Lancair, which has developed a number of high-performance kits. The most powerful is the Lancair Propjet, a four-place kit with cabin pressurization and a turboprop engine, cruising at 24,000 feet and 370 knots. Although aircraft such as this are considered "home-built" for legal reasons, they are typically built in the factory with the assistance of the buyer. This allows the company which sells the kit to avoid the long and expensive process of certification, because they remain owner-built according to the regulations. These regulations, under the FAA, have just changed recently. The builder will now have to actually fabricate a certain percentage of his airplane from scratch.
Kit airplanes can be constructed out of any material that is light and strong enough for flight. Several common construction methods are detailed below.
Wood and Cloth
This is the oldest construction, as seen in the Wright Flyer, and therefore the best known. For this reason, homebuilt airplanes associations will have more specialists for this type of craft than other kinds.
The most commonly-used woods are Sitka spruce and Douglas fir, which offer excellent strength-to-weight ratios. Wooden structural members are joined with adhesive, usually epoxy. Unlike the wood construction techniques used in other applications, virtually all wooden joints in aircraft are simple butt joints, with plywood gussets. Joints are designed to be stronger than the members.
After the structure has been completed, the aircraft is covered in fabric (usually aircraft-grade polyester).
The advantage of this type of construction is that it does not require complex tools and equipment, but commonplace items such as saw, planer, file, sandpaper, and clamps.
During World War 2 the Mosquito attack plane was constructed in this manner. It was one of the most successful airplanes of the war.
Amateur-built wood/cloth designs include:
"A recent trend is toward wood-composite aircraft. The basic load carrying material is still wood, but it is combined with foam (for instance to increase buckling resistance of load carrying plywood skins) and other synthetic materials like glass- and carbon fibre (to locally increase the modulus of load carrying structures like spar caps, etc). An example of a wood-composite design is the Ibis experimental aircraft project, designed by Roger Junqua, and the KR series of homebuilts designed by Ken Rand." (Wikipedia)
Kit airplanes built from metal use similar techniques to those kit airplanes built in a factory. They can be more challenging to build, requiring metal-cutting, metal-shaping, and riveting. A component assembly kit has the material needed to build part of the aircraft, such as the fuselage. Such kits are also available for the other types of aircraft construction. The technique to build a metal airplane has become easier over the years. Vans Aircraft, for example, ship their kits with holes pre-drilled so that gigs are, usually, not required during construction.
There are three main types of metal construction. They are sheet aluminum, tube aluminum, and welded steel tube. The tube structures are covered in fabric in the same style as wooden aircraft are.
Examples of metal-based amateur aircraft include:
"Composite material structures are made of cloth with a high tensile strength (usually fiberglass or carbon fiber, or occasionally Kevlar) combined with a structural plastic (usually epoxy, although vinylester is used in some aircraft). The fabric is saturated with the structural plastic in a liquid form; when the plastic cures and hardens, the part will hold its shape while possessing the strength characteristics of the fabric." (Wikipedia)
The two main types of kit airplanes built from composites are molded composite ( where major structures like wing skins and fuselage halves are prepared and cured in molds), and moldless composite (where shapes are carved out of foam and then covered with fiberglass or carbon fiber).
The advantages of constructing composite kit airplanes include smooth surfaces, which cuts down on drag, the ability to do compound curves, and the ability to place fiberglass or carbon fiber in optimal positions, orientations, and quantities. The downsides of composite airplane construction include the need to work with chemical products as well as low strength in directions perpendicular to fiber.
Examples of amateur craft made of composite materials include:
For information on airplane propellers for your kit airplane, please visit my Airplane Propellers page
Vans Aircraft - Kit Plane Manufactureurs Extraordinaire!!
Murphy Aircraft Mfg - Canadian Makers of Home Built Bush Planes.
Glasair Aviation - Makers Of Composite Airplane Kits
Mustang II Aeronautics - Home of the Midget Mustang and Mustang II
Sonex Aircraft - Makers of Sonex, Waiex, and Xenos Light Sport Airplanes
Zenith Aircraft Company - Kit Airplanes for Sport Pilots
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