The Manly–Balzer was the first purpose-designed aircraft engine, built in 1901 for the Langley Aerodrome project. The engine was originally ordered from Stephen Balzer (1864–1940) in New York, but his five-cylinder radial engine design failed to live up to its claims. Langley's chief assistant, Charles Manly, then reworked the engine to produce a design that held the record for power-to-weight ratio for any engine for many years. Manly later worked for Glenn Curtiss, and was one of the team-members who designed the mass-produced Curtiss OX-5. Background The problem with powering the Aerodrome had been known as early as 1898 when work on the person-carrying versions first started. At the time the gasoline engine was a fairly new invention, and no engine in the world had the needed performance. After a short search they decided to contract the development to one of the few engine builders in the area, New York's Stephen M. Balzer. Balzer was a Hungarian immigrant who had a mechanical bent and started designing various devices while working in the watch repair department in Tiffany's. He followed this with a night course in engineering, and struck out on his own to develop what would become New York's first car in 1894, a small four-wheel carriage powered by a three-cylinder rotary engine of his design. Balzer was convinced he could build an engine to Langley's requirements by scaling up his existing design into a larger five-cylinder one. Langley gave him a contract in December 1898, and work started on the new design. Engine development The engine was completed fairly quickly, but proved to be underpowered, delivering compared to the Langley wanted. As would be rediscovered by many engineers after him, Balzer found that scaling up his existing design simply didn't work. Manly worked with him to try to improve the design, but by 1899 it was clear that it wasn't going to work any time soon. Balzer never gave up on the engine, and continued to work on it for years, eventually going bankrupt. Every engineer Manly met on a trip to Europe in 1900 told him the rotary design was hopeless. Manly eventually became convinced as well and started work on adapting one of the existing Balzer engines into a non-rotating radial engine. The main concern was cooling, which he solved by welding a jacket to each cylinder and filling it with water. The results were promising, and