Napier-Halford Dagger Series II, H-24 Engine
date: label: Date
content: Circa 1938
name: label: Manufacturer
content: Napier Aero Engines Ltd.
notes: label: Physical Description
content: Type: Reciprocating, 24 cylinders, Air cooled, Supercharged
label: Physical Description
content: Power rating: 470 kW (630 hp) at 3,500 rpm
label: Physical Description
content: Displacement: 16.8 L (1,027 cu in)
label: Physical Description
content: Bore and Stroke: 96.8 mm (3.8125 in.) x 95.3 mm (3.75 in.)
label: Physical Description
content: Weight: 587 kg (1,295 lb)
label: Summary
content: Frank B. Halford was a talented independent British engine designer of the early and mid-twentieth century who worked for a number of manufacturers including de Havilland, Cirrus and Fiat. In 1928, he contracted with Napier for design of a series of air-cooled engines in a vertical H configuration having twin crankshafts geared together. There were two basic types, the 16-cylinder Rapier and the 24-cylinder Dagger. The Rapier, produced in small numbers, powered the Short Mercury seaplane. By 1935, the Dagger served a large military market, and the British Air Ministry ordered it in quantity. Both the lower powered Dagger I and Dagger II versions powered the Hawker Hart aircraft. The final version, the 712 kW (955 shp) Dagger VIII, powered the Fairey Battle I and Handley Page H.P.52 Hereford I.
label: Summary
content: Late in his career, with access to the work of Frank Whittle, Halford led the de Havilland Engine Co. where he designed turbine engines.
place: label: Country of Origin
content: United Kingdom
setName: label: See more items in
content: National Air and Space Museum Collection
creditLine: label: Credit Line
content: Transferred from the U.S. Navy
dataSource: label: Data Source
content: National Air and Space Museum
identifier: label: Inventory Number
content: A19710930000
objectType: label: Type
content: PROPULSION-Reciprocating & Rotary
objectRights: label: Restrictions & Rights
content: CC0
physicalDescription: label: Materials
content: Steel, Paint, Aluminum, Magnesium, Wood, Stainless Steel, Rubber, Copper
label: Dimensions
content: Height 175.3 cm (69 in.), Width 99.1 cm (39 in.), Depth 223.5 cm (88 in.)