Experimenting, two years after the appearance of the 'kite-carriage,' on the helicopter principle, W. H. Phillips constructed a model machine which weighed two pounds; this was fitted with revolving fans, driven by the combustion of charcoal, nitre, and gypsum, producing steam which, discharging into the air, caused the fans to revolve. The inventor stated that 'all being arranged, the steam was up in a few seconds, when the whole apparatus spun around like any top, and mounted into the air faster than a bird; to what height it ascended I had no means of ascertaining; the distance travelled was across two fields, where, after a long search, I found the machine minus the wings, which had been torn off in contact with the ground.' This could hardly be described as successful flight, but it was an advance in the construction of machines on the helicopter principle, and it was the first steam-driven model of the type which actually flew. The invention, however, was not followed up.

After Phillips, we come to the great figures of the middle nineteenth century, W. S. Henson and John Stringfellow. Cayley had shown, in 1809, how success might be attained by developing the idea of the plane surface so driven as to take advantage of the resistance offered by the air, and Henson, who as early as 1840 was experimenting with model gliders and light steam engines, evolved and patented an idea for something very nearly resembling the monoplane of the early twentieth century. His patent, No. 9478, of the year 1842 explains the principle of the machine as follows:--