Hayne Constant, CB, CBE., MA., FRAeS., FRS,[1] (26 September 1904 – 12 January 1968) was an English mechanical and aeronautical engineer who developed jet engines during World War II.
Constant stayed at Cambridge for a post graduate year in 1927/28 and then joined the Royal Aircraft Establishment at Farnborough.
In 1936 Henry Tizard persuaded Constant to return to the RAE from Imperial College to help with the development of A.
A series of engines to Griffith's design were built under Constant's direction at the RAE.
Hayne was director of the National Gas Turbine Establishment from 1948 to 1960, and was awarded the Gold Medal of the Royal Aeronautical Society in 1963 for his outstanding contribution to gas turbine development.