Napier & Son - World War I and Interbellum

World War I and Interbellum

Early in the First World War, Napier was contracted to build engines from other companies' designs: initially a V12 Royal Aircraft Factory model and then Sunbeam Arabs. Both proved to be rather unreliable, and in 1916 Napier decided to design their own instead, an effort that led to the superb W-block 12-cylinder Lion. The Lion was a best-seller for the company, and they eventually dropped all the other aero-engines. The Lion went on to be used in to set the Land Speed Record in Malcolm Campbell's Napier-Campbell Blue Bird and Campbell-Napier-Railton Blue Bird and Henry Segrave's Golden Arrow.

Vehicle production continued and 2,000 trucks and ambulances were supplied to the War Office. Montague Napier's health declined and in 1917 he moved to Cannes, France, but continued to take an active involvement in the company until his death in 1931.

During the First World War the company was contracted to build 600 aircraft at the Acton factory (50 Royal Aircraft Factory R.E.7, 400 Royal Aircraft Factory R.E.8 and 150 Sopwith Snipes).

In 1919 civilian car production recommenced with a 6-litre six-cylinder car, the T75. These were very expensive, costing about the same as a Rolls-Royce Silver Ghost and in the early 1920s sales declined. The last cars were made in 1924. An attempt was made to buy the bankrupt Bentley company in 1931 but Napier was outbid at the last minute by Rolls-Royce. The last vehicle project was a three-wheeled tractor-trailer goods vehicle, but rather than produce this themselves they sold it to Scammell, who made several thousand.

In the 1930s the introduction of much larger and more powerful aero-engines from other companies suddenly ended sales of the Lion. Napier quickly started work on newer designs, building on experience gained on the X style 16-cylinder, 1,000 hp (746 kW) Cub, used in the Blackburn Cubaroo single-engined bomber of the 1920s, and the resulting later 16-cylinder Rapier and 24-cylinder Dagger were both air-cooled H-block designs. Neither the Rapier nor the Dagger proved very reliable, due to poor cooling of the rearmost cylinders, and even the Dagger's 1,000 hp (750 kW) was less than its competitors' offerings when shipped.