The
Monosoupape (
French for
single-valve), was a
rotary engine design first introduced in 1913 by
Gnome Engine Company (renamed
Gnome et Rhône in 1915). It used a clever arrangement of internal
transfer ports and a single pushrod-operated exhaust valve to replace a large number of moving parts found on more conventional rotary engines, and made the
Monosoupape engines some of the most reliable of the era. British aircraft designer
Thomas Sopwith described the
Monosoupape as "one of the greatest single advances in aviation".