ADC Cirrus
The ADC Cirrus and Cirrus-Hermes are British aero engines of the mid-1920s. Sometimes known as the Blackburn Cirrus,[1] examples remain airworthy today.
Design and development
ADC Cirrus engines were originally built by ADC Aircraft until Cirrus Aero Engines Limited was formed in 1927. The company became Cirrus-Hermes in 1931 when it was bought by the Cirrus-Hermes Engineering Company and later became the Cirrus Engine Section of Blackburn & General Aircraft Limited in 1934, and operated as a separate division until production ended in the post-World War II era.[2]
Cirrus's first product was the 90 hp (67 kW) Cirrus I, which passed its 50 hour type rating in 1925. It was the first air-cooled inline engine, a design by Frank Halford that proved extremely popular for light aircraft. The basic layout (using one cylinder bank of an ADC Airdisco V-8 engine)[3] was quickly copied by a number of other manufacturers. Later versions named the Cirrus II, and Cirrus III were produced each with slightly greater displacement, and power (Cirrus II - 85 hp, Cirrus III - 90 hp).
The next model line, Cirrus-Hermes I, II, and IV were produced ranging in power from 105 hp to 140 hp depending on type. The later Cirrus engines were designed to run inverted.[4]
Variants
A comparison of Cirrus Hermes I (left) and Cirrus III (right)
- Cirrus I
- (1925)
- Cirrus II
- (1926)
- Cirrus III
- (1929)
- Cirrus IIIA
- (1933)
- Cirrus-Hermes I
- (1929)
- Cirrus-Hermes II
- (1930)
- Cirrus-Hermes IIB (inverted)
- (1931)
- Cirrus-Hermes IV
- (1930)
- Cirrus-Hermes IVA
- (1929) Inverted engine
Cirrus-Hermes I engine in Roe IV replica, Shuttleworth collection
Applications
List from Lumsden.[5][6]
Cirrus
Cirrus-Hermes
Engines on display
A Cirrus Hermes
Specifications (Cirrus I)
Data from Lumsden.[2]
General characteristics
- Type: Inline, air-cooled, upright 4-cylinder piston engine
- Bore: 4.13 in (105 mm)
- Stroke: 5.12 in (130 mm)
- Displacement: 274.36 cu in (4.5 L)
- Length: 45.8 in (116.3 cm)
- Width: 18.26 in (46.4 cm)
- Height: 34.3 in (87.1 cm)
- Dry weight: lb ( kg)
Components
- Valvetrain: 1 inlet and 1 exhaust valve per cylinder
- Fuel system: 1 Claudel carburettor
- Fuel type: 70 octane
- Cooling system: air
Performance
See also
- Related development
- Comparable engines
- Related lists
References
Notes
- ↑ This name applies only to the revised range of Cirrus engines produced after 1934 by Blackburn, e.g. the Blackburn Cirrus Major.
- ↑ 2.0 2.1 Lumsden 2003, p. 130.
- ↑ Gunston 1989, p. 40.
- ↑ Lumsden 2003, p.132.
- ↑ Lumsden 2003, pp. 130-132.
- ↑ Cirrus engines may not be the main powerplant for these aircraft types (test installations are included).
- ↑ Wesselink 1982 p.80
- ↑ Wesselink 1982 p.81
Bibliography
- Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
- Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.
- Wesselink, Theo; Postma, Thijs (1982). De Nederlandse vliegtuigen. Haarlem: Romem. ISBN 90 228 3792 0.
External links
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