In 1807 Sir George Cayley realised that a powerful but light 'prime-mover' was going to be essential for powered flight. He attempted to build an internal combustion engine fuelled with grains of gunpowder, but unfortunately it did not work for more than a few strokes.
The French naval officer Felix Du Temple used a steam engine with an advanced 'flash' steam boiler to power his monoplane for a short hop in 1874, probably the first successful powered flight.
Unable to purchase a petrol engine that was light enough, the Wright Brothers made their own four cylinder engine that produced 12 hp. It was built in six weeks by Charles Taylor, the skilled mechanic who ran their bicycle shop, and designed it with them. To save weight they used an aluminium casting for the engine block, an innovation at that time.