PERFECTING THE GLIDER. This wikipedia entry describes the years of work which were dedicated to manned flight by the Wright brothers. Those years were devoted to work on the control of a glider, both by improving glider design and by learning piloting skills.
Their chief rival in the United States was Samuel Langley, the Secretary of the Smithsonian Institute, who had received a $50,000 grant from the United States Army for use in developing a series of attempts at manned flight. Langley was one of the experimenters described by wikipedia “who built powerful engines, attached them to airframes equipped with unproven control devices, and expected to take to the air with no previous flying experience”. In contrast, the Wright brothers did not add an engine to their gliders until 1903, and then it was an engine built in six weeks by their shop mechanic, Charlie Taylor.
Their patent application in early 1903 was based on their 1902 glider, which did not involve the use of an engine. The wikipedia entry says: “The patent’s importance lies in its claim of a new and useful method of controlling a flying machine, powered or not.”