Hargraves made a major contribution to the study of aerodynamics (the
study of the effect that a solid body has on air, when travelling through
it), when his experiments were influential in the development of the cambered
aerofoil (a structure with curved surfaces which gives lift when in
flight). The tailplane, wing and fin are examples of aerofoiles.
Hargraves used Horatio. F. Phillips findings in 1880 to help him increase
the efficiency of his box kite. Phillips created the double-surfaced aerofoil.
This type of aerofoil was capable of producing a lower pressure above
the wing surface than below. The difference in pressures would certainly
allow the wing to rise faster.
Hargraves gave up all experiments a year later after he repeatedly failed
to create powered flight. The image below shows the Single-celled,
reflex-curved aerofoil kite, designed by Hargraves.
The Royal Aeronautical Society has lent it to the Science museum.