Flamsteed Astronomy Society
Eddie has a keen interest in maritime history as well as the development of astronomy, and it always delights him to come across something which has links with both of these - something which unites the two main aspects of the National Maritime Museum. Earlier this year, while he was visiting Newcastle upon Tyne, he stumbled across just such a link in the Discovery Museum there - the first steam turbine ship ‘Turbinia’.
Charles Algernon Parsons was born in London in June 1854. He seems to have been a natural engineer, and studied mathematics and mechanics at Cambridge. Graduating in 1877 with a first class honours degree he joined the firm of W.G. Armstrong & Co., engineers and shipbuilders on the Tyne. He was responsible for several inventions including a steam turbine engine for driving an electrical dynamo. The success of this engine convinced him that the theoretical advantages of the steam turbine (i.e., higher thermal efficiency and reliability) could be captured in practice, and he set up a company C.A. Parsons & Co., to exploit these engines and apply them to ship propulsion.
Charles Parsons & Turbinia
— by Eddie Yeadon, November 2, 2004
Parsons designed Turbinia largely by himself, although he had not been trained as a naval architect. He decided on a very long, narrow boat which he first called the Experimental Launch, later Turbinia, launched in 1894.
In the first trials with a single turbine, the boat only achieved 20 knots despite the high power known to be delivered. Parsons traced this to cavitation* in the propeller which was turning at much higher speeds than conventional ships.
After further development he installed three turbines, high, medium and low pressure in series, each directly driving a separate propeller shaft. To avoid cavitation he fitted very small diameter propellers and mounted three of these propellers axially on each shaft. Because the intermediate turbine shaft is central in the hull, the rudder has to be offset to one side. Interestingly, the rudder is displaced to port, not starboard as would have been more in the nautical tradition.
With an eye to publicity, Parsons arranged to demonstrate his boat at Queen Victoria’s Diamond Jubilee Fleet Review in Spithead in 1897. There, Turbinia demonstrated a speed (34.5 knots) and manoeuvrability which completely outstripped all the naval guard and patrol vessels on duty.
The navy, which had been keeping an eye on the development of steam turbines, responded rapidly and the first two torpedo-boat destroyers powered by steam turbine, Viper and Cobra, were launched only two years later, in 1899. By 1906, turbines were being adopted for the revolutionary new all-big-gun battleship HMS Dreadnought.
So - interesting maritime history, but what has all this to do with astronomy?
Well, Charles Parsons was the son of Third Earl of Rosse, and the family home was at Birr Castle, near Parsonstown in Ireland. The Earl was a wealthy and enthusiastic amateur astronomer and he built the largest telescope in the world - a reflector with a 6 foot diameter mirror. The last slide is how it looks today, after restoration.
Turns out there is another ‘Parsons’ link between astronomy and the engineering company.
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*cavitation — a propeller rotating too quickly just boils the water behind it creating bubbles or ‘cavities’. The energy of the engine is wasted rather than driving the vessel forward.
Thomas Grubb FRS, an engineer at the Bank of Ireland, had established a first-class reputation for telescope manufacture and founded the Charlemont Bridge Works in Dublin. Among many fine telescopes Thomas Grubb built the Great Melbourne Reflector in 1862 (destroyed in the Mt Stromlo fire). Thomas retired in 1868 and the business passed to his son Howard (later Sir Howard) Grubb who moved to Rathmines. Howard Grubb established the leading optical and telescope manufacturing enterprise in the British Empire. His work included the 27-inch Vienna refractor, 1880 (for 5 years the largest in the world) and the Greenwich Great Equatorial 28-inch refractor, 1894.
In 1918 the Dublin Works was moved to St Albans, Herts. and in 1925 on Sir Howard’s retirement, the business was acquired by Sir Charles Parsons FRS. Parsons built a new works at Walkergate, Newcastle, for the business Sir Howard Grubb, Parsons, & Company — “Grubb-Parsons”. Well, well. Eddie Yeadon