Pilcher's plans were lost for many years, and his name was also long forgotten except by a few enthusiasts. When the centenary of the
Wright brothers' flight approached, a new effort was made to find the lost work, and some correspondence was found in a private American collection. From this it was possible to discern the general direction of his plans and the basis of his design. Based on Lilienthal's work, Pilcher understood how to produce lift using winglike structures, but at this time a full mathematical description was years away, so many elements were still missing. In particular, Pilcher was stuck trying to design a wing that could lift the weight of an engine, the aircraft itself and the occupant – each increase in wing area increased the weight so much that yet more lift was required, requiring a larger wing – a seemingly vicious circle. Pilcher's breakthrough, thanks to correspondence with another pioneer,
Octave Chanute, was to stack smaller, lighter wings one atop the other in an arrangement we know today as the biplane or triplane. This allowed the wings to generate much more lift without a corresponding increase in weight. In 2003, a research effort carried out at the School of Aeronautics at
Cranfield University, commissioned by the
BBC2 television series
Horizon, has shown that Pilcher's design was more or less workable, and had he been able to develop his engine, it is possible he would have succeeded in being the first to fly a heavier-than-air powered aircraft with some degree of control.{{cite web|url=https://www.bbc.co.uk/science/horizon/2003/percypilchertrans.shtml Cranfield built a full-sized working replica of Pilcher's aircraft, but, based on
wind tunnel tests with a scale model, they made several alterations to Pilcher's original designs, which they speculated Pilcher would have made, including filling in cut-away sections of the wings to increase the wing area, and therefore lift, and adding a swinging seat to aid control of the aircraft through shifting body weight; a refinement developed by Octave Chanute, which they believed Pilcher would have been aware of. They also added the Wright brothers' innovation of wing-warping as a safety backup for roll control. Pilcher's original design did not include aerodynamic controls such as
ailerons or
elevators. After a very short initial test flight piloted by the aircraft designer Bill Brookes, the craft achieved a sustained flight of 1 minute and 25 seconds, compared to 59 seconds for the Wright Brothers' best flight at
Kitty Hawk in
North Carolina. This was achieved under dead calm conditions as an additional safety measure; the Wrights in 1903 flew in a 20 mph+ wind to achieve sufficient airspeed. A monument to Percy Pilcher is located at Upper Austin Lodge to the south of
Eynsford, Kent. He regularly flew his
Hawk glider from this location. ==See also==