Clerget-Blin Rotary Engine Documentation

A curated digital reference collection covering the Clerget-Blin rotary aviation engines, with particular emphasis on the 9B and 9BF, early 110 HP Clerget material, illustrated parts information and associated Sopwith airframe rigging notes. It is intended for aviation historians, restorers, museum teams, engineers and researchers studying the technology and operation of First World War rotary engines.

This is a structured archival collection built from the supplied historical scans. The collection may be expanded when additional verified Clerget-Blin records are identified, while the documents listed below define the present working scope.

Historical and design note

The Société Clerget-Blin et Cie of Levallois-Perret, France, developed its rotary engine range from Pierre Clerget’s earlier stationary, automotive and water-cooled aviation-engine experiments. The first rotary designs appeared in 1913, with major military variants entering service during the First World War. Clerget engines were also produced under licence in the United Kingdom, including by Gwynnes Ltd. and Ruston, Proctor & Co. Production is generally placed in the period 1913–1920, when the company entered liquidation.

Primary wartime applications associated with the range include the Sopwith Camel F.1, Sopwith Triplane, Sopwith 1½ Strutter, Avro 504 variants and Nieuport 12/17bis. After the war, surplus engines and airframes continued in limited civil, training, recreational and early rotorcraft contexts. Surviving engines today are principally associated with museums, restorations and carefully controlled heritage flying.

Technical reference: Clerget 9B and 9BF

• Type: air-cooled rotary engine, with the crankcase and cylinders rotating around a stationary crankshaft.
• Configuration: nine-cylinder, single-row radial arrangement.
• Clerget 9B: approximately 130 HP, 120 mm bore and 160 mm stroke, about 16.29 litres displacement.
• Clerget 9BF: approximately 150 HP, with the longer 172 mm stroke and about 17.5 litres displacement.
• Compression ratio: 4.56:1 in the supplied technical overview.
• Fuel and lubrication: early aviation petrol with total-loss lubrication using castor oil.
• Engineering features: independent intake and exhaust valves, separate pushrods, a segment-gear cam assembly and a brass obturator ring below the piston crown to accommodate thermal expansion.

The supplied 1917 9B/9BF cover page states a speed of 1,250 RPM and a weight of 181 kg (400 lb) including the oil pump, air pump and two magnetos. Historical sources may use different weight bases, so figures should be read against their individual source documents.

Documents in the present collection

1. Clerget Patent Aero Engines 9B—130 Horse / 9BF—150 Horse, 1917, technical reference.
2. Illustrated List of Parts with Code-Words for Clerget 9B & 9BF Patent Aero Engines, illustrated parts list.
3. Royal Air Force Technical Notes (Series I), 110 H.P. Clerget, technical note; date not stated on the supplied cover.
4. Moteurs Clerget-Blin—Levallois-Perret, French reference volume; the supplied cover does not establish a complete edition record.
5. Sopwith Biplane F.1 130 H.P. Clerget Rigging Notes, Part # BSSOPWITHBIPLANE RNC, circa 1917–1918, service/airframe setup manual.
6. Sopwith 1½ Strutter 110 H.P. Clerget Rigging Notes, Part # BSSOPWITH11/2 RIGG C, circa 1916–1917, service/airframe setup manual.

Format and delivery

Digital PDF access is delivered electronically after purchase. Files are supplied as compressed RAR/ZIP archives where applicable. On Windows, use WinRAR or 7-Zip; on Mac, use The Unarchiver or a comparable extractor. After extraction, the documents open as standard PDFs for searching, reading and printing.

Regulatory and archival notice

This collection contains historical engine, parts and airframe setup material. It is supplied for historical reference, research, simulation, museum and restoration study, and is not current approved airworthiness data, a maintenance release, a repair instruction or an alternative to current data from the applicable authority or Type Certificate holder. The original Clerget-Blin manufacturing company is no longer operating, and no current Type Certificate holder is identified in the supplied records.

Legal Notice: This digital compilation, structure, indexing and presentation are © Sicuro Publishing. Underlying historical documents remain subject to their own copyright, provenance and distribution status. No endorsement by Clerget-Blin, the RAF, Sopwith, any aircraft manufacturer or any museum is implied.

Export Notice: Buyers are responsible for complying with applicable export-control, import and destination-country rules. Historical age alone does not determine reproduction or distribution rights.