Robert D. Napier (1821 – May 1885) was a Scottish

engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the l ...

, and the youngest son of

David Napier (marine engineer) David Napier (10 November 1790– 23 November 1869) was a Scottish marine engineer. Napier began in his father's works at Camlachie and built the boiler for Henry Bell's ''Comet'' in 1812. Subsequently, he took over the foundry and establis ...

. Educated in Liverpool and London, Robert D. Napier worked, with brothers John D. and Francis ("Frank") for his father's shipbuilding firm. At the age of 30, he moved to Australia, where he oversaw dredging operations in Sydney Harbour. While there, he invented the "Differential Self-Acting Friction Brake" and the "Napier Windlass". In 1856 he brought out to

Port Adelaide, South Australia Port Adelaide is a port-side region of Adelaide, approximately northwest of the Adelaide CBD. It is also the namesake of the City of Port Adelaide Enfield council, a suburb, a federal and state electoral division and is the main port for the c ...

in sections, a paddle-steamer ''Moolgewanke'' for trading on the

River Murray The Murray River (in South Australia: River Murray) (Ngarrindjeri: ''Millewa'', Yorta Yorta: ''Tongala'') is a river in Southeastern Australia. It is Australia's longest river at extent. Its tributaries include five of the next six longest r ...

. He and partner Capt. William Webb operated her for a few years from Goolwa before selling her, with barge ''Unknown'', to George Bain Johnston. He was also involved with Capt. William McCoy in operating the paddle steamer ''Leichardt''. He returned to Scotland about 1865–1866 and established a new business "Napier Brothers" with his brother John. Napier also experimented and wrote on a number of important scientific topics. He is best known for his 1866 work "On the Velocity of Steam and other Gases, and the True Principles of the Discharge of Fluids". This work was one of the earliest discussions of the diverging nozzle, later known as the

de Laval nozzle A de Laval nozzle (or convergent-divergent nozzle, CD nozzle or con-di nozzle) is a tube which is pinched in the middle, making a carefully balanced, asymmetric hourglass shape. It is used to accelerate a compressible fluid to supersonic speeds ...

. It presented the well-known "Napier formula" for steam loss through an orifice. He also wrote a number of papers on the flow of water through nozzles.Obituary in ''

Engineering Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...

'', Vol. 39, 22 May 1885 He never married, and he died in Glasgow in May, 1885.

References

1821 births 1885 deaths Engineers from Glasgow British marine engineers Scottish company founders 19th-century Scottish businesspeople 20th-century Scottish businesspeople {{UK-engineer-stub