In 1926 Bristol began studies to integrate the Burt-McCollum sleeve valve concept into selected new engine designs. The sleeve valve, which moved within the cylinders, functioned as both an intake and exhaust valve. Relative to an engine with conventional intake and exhaust valves, the advantages of the sleeve valve design included a lower parts count, operational smoothness, and improved fuel economy.

In March 1935, Roy Fedden and L.F.G. Butler began the design of the Bristol Hercules, the third Bristol engine model to incorporate sleeve valves. After overcoming difficult development problems, the Hercules was produced in larger quantity than any other Bristol engine. This engine, a Model VI, powered World War II aircraft such as the Short S.29 Stirling III, Avro 683 Lancaster II, Handley Page H.P.61 Halifax III, and Bristol 156 Beaufighter. After the war it powered such commercial aircraft as the Vickers 623 Viking IA, Short S.45 Solent 3, and Bristol 170 Freighter.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date 1935 Country of Origin United Kingdom Type PROPULSION-Reciprocating & Rotary Manufacturer Bristol Aeroplane Company Limited
 Physical Description Type: Reciprocating, sleeve-valve engine, 14 cylinders, 2-row radial, air cooled, supercharged Power rating: 1,182 kW (1,585 hp) at 2,900 rpm Displacement: 38.7 L (2,360 cu in.) Bore and Stroke: 146 mm (5.75 in.) x 165 mm (6.5 in.) Weight (dry): 858 kg (1,890 lb) Dimensions 3-D: 182.9 × 142.2 × 133.3cm (6 ft. × 4 ft. 8 in. × 4 ft. 4 1/2 in.)
Overall: 1890lb. (857.3kg)
Storage (Stand): 7 × 5 ft.
 Materials Ferrous Alloy
Aluminum Alloys
Plastic
Paints
Possible Rubber
Cork
Adhesive
Non-Magnetic White Metal
 Inventory Number A19580003000 Credit Line Gift of the Bucks County Scientific Society of Morrisville, Pennsylvania Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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