CLERGET PATENT
AERO ENGINES
Instructions
and List of Parts
9B & 9BF
GWYNNES LTD, Hammersmith & Chiswick, London, 1917
A rare original 1917 edition of the Clerget manufacturer's instruction and parts manual for the Clerget 9B 130 hp and 9BF 150 hp rotary aero engines. The 9B engine was introduced in 1915 and revised models such as the 9BF were developed later in 1915. During WW1 the Clerget 9B was fitted to many successful RFC and RAF aircraft, including the Sopwith Camel, Sopwith Triplane and Avro 504. The manual includes a general description of the engines, directions for stripping and re-assembling, adjustment instructions, and details about mounting the engines. There is also a comprehensive illustrated list of parts and specialist tools, and a section of blank notes pages for any amendments that would have been added. The manual is illustrated with detailed line drawings and diagrams of the engines, components, and tools.
The book has ink stamps of '19 Training Depot Station, Equipment office, Royal Air Force' and 'X Aircraft Depot, Royal Air Force' dated 1918 on the front endpapers and in the text. Both of these units were established in Egypt during WW1. No.19 TDS, which carried out pilot training, was located at El Rimal, and later became known as RAF El Amirya. "X" Aircraft Depot was at Alexandria and assembled aircraft that had been shipped out from Britain, as well as repairing aircraft from units in Egypt and Palestine.
Clerget-Blin & Cie: was founded in 1913 when Pierre Clerget (1875-1943) joined forces with the industrialist Eugene Blin. From their premises at 37 Rue Cavé, Levallois-Perret, on the banks of the Seine about 4 miles from the centre of Paris, they produced a succesful range of aero engines. Clerget-Blin were best known for the air-cooled rotary engines which were built and licensed during WWI, and which powered some of the RFC’s most famous aircraft, including the Sopwith Pup, Sopwith Camel and Avro 504K. Gwynnes Ltd held the British manufacturing rights for Clerget designs during the first world war. Clerget designed air-cooled rotaries with seven, nine, and eleven cylinders. Their cylinders, machined with integral cooling fins from solid steel billets, were gripped between the two steel crankcase halves. The crankcase nose piece carried the propeller hub.
Clerget 9B: was a nine cylinder 130 hp rotary engine designed by Pierre Clerget. During WW1 it was produced in France and also under licence in Britain by Gwynnes of Hammersmith, Gordon Watney (Weybridge), Ruston Proctor of Lincoln, and Humber-Bentley (Coventry). What distinguished the Clerget rotary engine from rival engines made by Gnome and Le Rhone was that the Clerget had normal intake and exhaust valves, unlike the Gnome, and the connecting rod arrangement was much simpler than the Le Rhone. A source of failure among the Clerget engines were the special-purpose piston rings, or obturator rings. These rings were often made from brass and only had a lifespan of a few hours. The Clerget engines were considered reliable but they cost more per unit to produce than their rivals. Unlike other contemporary rotaries in which the ignition system was either switched on or off to provide a rudimentary form of engine speed control, the Clerget featured a throttle. The 9B was considered to be one of the best WW1 aero engines, and was used extensively by aircraft manufacturers such as Sopwith, Avro and Vickers, powering iconic aircraft including the Sopwith Camel, Vickers Gunbus, and Avro 504. The 9BF was introduced in 1915 and was a more powerful 150 hp, nine-cylinder long stroke version of the Clerget 9B. It was the most numerous British production engine with 2,350 units being built.
Condition:
In good condition. The boards are in good condition, with general signs of wear and use and some marks. The binding and hinges are secure. The text and illustrations are in good condition, with some marks and some pencil annotation by the original RAF owner. The book has ink stamps on the front endpapers and in the text of '19 Training Depot Station, Equipment office, Royal Air Force' and 'X Aircraft Depot, Royal Air Force'.
Published: 1917
Blue boards with gilt titling
Illustrated with line drawings and diagrams
Dimensions: 155mm x 230mm
Pages: 43 (plus blank notes pages)
