Until the mid-1920s, wood propellers turned the power of the aircraft engine into thrust to propel aircraft forward. They featured a permanently set blade angle, called fixed-pitch, and were made from layers of wood. They were cheap, easy to manufacture, and light, and were the dominant propeller type for high performance aircraft until the mid-1920s. After that, small general aviation aircraft relied upon them for thrust. The Vin Fiz, T-2, Douglas World Cruiser Chicago, and the Piper Cub feature wood propellers.