The Weymann W-1 was a French single seat biplane fighter aircraft, built during World War I.
It had a most unusual layout, with an engine buried in the fuselage driving a pusher configuration propeller behind a cruciform tail.
It was an all-metal aircraft; a single bay biplane with constant chord, equal span, unswept and unstaggered wings, braced by parallel interplane struts assisted by flying wires.
The fuselage tapered both in height and width to the tail, where the tailplane and split elevators were mounted on its upper surface.
[1] The W-1 made only two short test flights, the first in the autumn of 1915, which revealed severe and ultimately insurmountable cooling problem with the buried engine.