Butler and Edwards
Great Britain, 1867. J. W. Butler and E. Edwards, patent an aeroplane probably based on some recollection of their school-boy days, when they threw paper arrows in class. The stability of these Iittle projectiles is quite good fore-and-aft, because the supporting surfaces increase in area while the intensity of the pressures diminish toward the rear, but the power required is great, and there is probably no aviating merit in this form.
Butler and Edwards' Delta planform jet of 1867
The form here shown (fig. 1) is the simplest, the top planes being set at a slight diedral angle, in order to procure lateral stability.
Butler and Edwards' dual Delta planform jet of 1867
Butler and Edwards also proposed to combine the planform in a variety of ways, superposing the sustaining planes, or (fig. 2), placing two machines side by side, or both, and bracing between by diagonal ties.
The motive power was to be placed in a car, forward of the centre of figure, and capable of being moved forward and back, so as to shift the center of gravity to correspond with the center of pressure at varying angles of flight.
The power was to consist in jets of steam issuing against the air in the rear; but, suspecting that this would be enormously wasteful, the patentees reserved the right of using screw propellers, driven either by the reaction of jets of steam issuing from curved arms (Hero's aeolipile) or by an ordinary steam-engine, in which case the steam was to be exhausted and condensed back into water, in cells formed by doubling the surfaces of the planes and thus providing hollow spaces.
adapted from Octave Chanute's Progress in Aerial Navigation