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John Penn (1805-1878)
5th President of the Institution of Mechanical Engineers (2nd term)
Penn was born at Greenwich, England in 1805. His father was established here as an engineer and millwright, working mainly in corn and flour mills. Penn entered his father’s works at an early age. His father died in 1843, and sole possession of the works passed to Penn. For some years previously he had had sole management of the works.
One of the earliest engines which he produced was the grasshopper engine. A 6 horse power grasshopper engine was the first steam engine to power the machinery at the works.
The 40 horse power beam engines fitted in the steamers ‘Ipswich’ and ‘Suffolk’ were probably the first marine engines to be designed and built by Penn. These engines, with some modifications, were fitted to the four passenger boats plying on the Thames between London and Greenwich.
Penn next turned his attention to improving the oscillating engine. In 1844 he replaced the engines of the Admiralty yacht, ‘Black Eagle’, with oscillating engines of double the power, without increasing either the weight or space occupied.
Another major innovation in marine engineering was Penn’s introduction of trunk engines for driving screw propellers in vessels of war. Here space was at a premium, and the engines had to be placed in as safe a position as possible. He kept the engines low in the vessel, and drove the screw directly. The first ships fitted with this engine design were the ‘Arrogant’ and the ‘Encounter’, and by the time of Penn’s death in 1878, 230 ships had been fitted with such engines.
Penn was also responsible for introducing wood bearings for screw-propeller shafts, presenting two papers on the subject to the Institution in 1856 and 1858. He was also associated with the application of superheated steam in marine engines, presenting a paper on this subject in 1859.
John Penn became a Member of the Institution in 1848. He served as President in 1858-1859, and again in 1867-1868.
In 1872, he handed over management of the works to his two eldest sons, retiring altogether in 1875. He died in 1878.