Homebuilt aircraft can be built out of a variety of materials, the newest and most popular option is composite materials. Composite materials have become popular with homebuilders because they are easy to work with and because they can be formed into any shape. This opens up design possibilities that were not possible with older construction methods.
Composites are two or more materials that are combined so that their advantages complement each other and there weaknesses cancel out. Composites aren’t necessarily high tech, plywood is an example of a low tech composite, however most homebuilt aircraft are built from fibreglass and foam.
The biggest advantage to using composite materials for your homebuilt aircraft is that they can be molded into almost any shape. No other construction materials can be formed into the streamlined shapes that composite materials can. Another advantage of composites is that they are easy to build. They are also incredibly strong and composite materials don’t rot or corrode. However this strength may not be an advantage and this one of the things that makes composites so controversial.
The strength of composite materials may actually be a disadvantage when it comes to the safety of composite aircraft. Composites have no give to them, they maintain their shape until they eventually shatter. This means there is no energy attenuation in the event of a crash. Metal aircraft deform on impact and absorb some of the energy, similar to the way crumple zones on a car protect drivers, this doesn’t happen in composite aircraft. Another issue with composite aircraft is repairability, composite aircraft are not easy to repair in the event of structural damage.
Composite materials are very sensitive to temperature so you will need a climate controlled workshop to build your aircraft. Because of this sensitivity they can’t be left out in the sun for long periods of time and almost always have to be painted white. Another issue with composites is that the materials can be unpleasant to work with. Strong chemicals are used in composite construction, they stink and many builders develop allergies to them. Your workspace must be very well ventilated.
Composite materials offer a number of advantages to the homebuilder, however like any construction material there are also disadvantages. There is no perfect material when it comes to building an airplane, you will have to do your research in order to determine what is the best choice for you.