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Early career with J. and H. McLaren in Leeds, where he patented a steam locomotive valve gear, jointly with Horace Sanderson and Henry St John Sanderson.
c.1900 Established the electrical engineering firm of Franklin and Isaacson in Great Wilson Street. Successful in supplying petrol engine-driven generating sets to cinemas and country houses.
1910 He employed Albert Edward Charlton, 22, who had been with Isaacson's previous firm, and together they produced their first radial (as opposed to rotary) engine, ordered by Claude Grahame-White. It quickly became apparent that it would be too heavy, so Isaacson designed a Mk 2 version of 40 HP, with 7 cylinders - see Isaacson. A novel feature was the use of gearing to give a propellor speed of half the crankshaft speed. After testing and modification, including a change from cast iron to steel cylinders, the engine was fitted to the Blackburn No. 2 monoplane.
The next engine gave 50 HP at 1600 rpm engine speed.
Another engine, giving a maximum output of 67.9 HP at 1080 rpm was designed to fit in the same mounting as the Gnome rotary engine. It weighed 196 lbs. It could be completely dismantled or reassembled in 22 minutes. An example was used in the 1912 Flanders biplane.
Isaacson is assumed to have died in a mental hospital in the latter part of WW1.
The above information is from 'Yorkshire's Early Flying Days' by Ronald Nelson Redman
1912 Granted a US patent (US 1027252 A) for the mounting of aerial propellors.
From a correspondent.
Rupert John Isaacson was born in the Calbourne district of the Isle of Wight sometime during 1880-81. His parents were Henry Isaacson, born c1858-59, and Isabel Isaacson, born c1855-56. She was born in Chile. There have been persistent stories that Rupert was the illegitimate son of a Russian of noble birth, but the truth would appear to be more prosaic.
He died on 29 April 1918 (at 9.25am) at Scalebor Park Hospital, Burley in Wharfedale, near Ilkley, West Yorkshire, leaving £125 to his mother, who had since remarried.
Isaacson was a prolific inventor with at least 29 patents to his credit, which dated between 1905 and 1919, some of which were jointly held with other individuals. Totals of six patents were granted both in the years 1909 and 1911, and most related to various aspects of internal combustion engines, including aero engines. Manufacture of the latter was undertaken by Manning, Wardle and Co of Leeds, the locomotive builders, and three patents related to steam locomotives, including a new valve gear. The latter received only a limited number of applications, mainly to 0-4-0 and 0-6-0 tank engines built by MW. However, of these the most notable was an unusual one-off 2-6-0 tank engine built by MW in 1909 for the Knott End Railway in Lancashire. This locomotive, together with biographical details concerning Isaacson, and the only known photograph of him, are contained in an article which I (Philip Atkins) wrote, entitled 'Blackpool, Britain's Most Obscure Locomotive?', which was published in Back Track, for January 1996, pp. 40-42.