What was the energy source used by the Wright Brothers' airplane

The Wright Brothers' airplanes were originally powered by wind. In 1903, the Wright brothers built the first manned aircraft, the Voyager 1. The airplane had a wingspan of 13.2 meters, with elevators in front and rudders at the back. Two sets of two-bladed propellers were driven by chains. The landing gear is skid-mounted, with a four-cylinder engine, weighing 70kg, with a power of 8.8kW, now on display is this famous airplane in aviation history. The airplane developed by the Wright Brothers was only composed of spruce and iron parts, and the control of the airplane needed to be controlled by its own balance, so its performance in terms of power was not particularly outstanding. The Wright brothers were famous American inventors. Their older brother is Wilbright (April 16, 1867 - May 12, 1912), younger brother is Orville Wright (August 19, 1871 - January 30, 1948).