Siddeley-Deasy

[6] During the First World War, Siddeley-Deasy grew to have 5,000 workers producing ambulances and aircraft engines, which included the Puma, a water-cooled straight-6 and the Tiger.

After the war, conditions for manufacturers were difficult, and in 1919 Siddeley suggested[9] a merger with Sir W G Armstrong Whitworth & Co Limited Motor Car Department.

Armstrong-Whitworth had been a supplier of Siddeley-Deasy engine castings and they had themselves made aircraft, chiefly designed by Frederick Koolhoven who left the company in 1917 and then by F. M Murphy.

[10] Armstrong Siddeley produced radial aircraft engines throughout its life, together with turbojets after the war.

This last company went on to produce Siskin fighters in large numbers, together with all the later Armstrong Whitworth designs.

[11] The two key members of the Siddeley Deasy design team stayed with the renamed company for many years.