The Cirrus and Hermes or Cirrus-Hermes are a series of British aero engines manufactured, under various changes of ownership, from the 1920s until the 1950s. The engines were all air-cooled, four-cylinder inline types, with earlier ones upright and later designs inverted. The first Cirrus design was created for the planned

de Havilland Moth The de Havilland Moths were a series of light aircraft, sports planes, and military trainers designed by Geoffrey de Havilland. In the late 1920s and 1930s, they were the most common civilian aircraft flying in Britain, and during that time ever ...

light aeroplane and, when it appeared in 1925, created the market for private flying. It and its successors were widely used for private and light aircraft from that moment on.

Design and development

ADC

The Cirrus engine originated in

Geoffrey de Havilland Captain Sir Geoffrey de Havilland, (27 July 1882 – 21 May 1965) was an English aviation pioneer and aerospace engineer. The aircraft company he founded produced the Mosquito, which has been considered the most versatile warplane ever built,D ...

's 1924 quest for a powerplant suited to a light two-seat sports biplane which would become the

. No suitable engine existed at the time combining an appropriate level of power with light weight, low cost and high reliability. The

Aircraft Disposal Company The Aircraft Disposal Company (ADC) or Airdisco, was a British firm established in March 1920 to take advantage of the large number of World War I-surplus military aircraft on the market.Gunston 2005, p.7. The company changed name in 1925 to ADC ...

, also known as Airdisco and ADC, were producing the low-cost Airdisco V8 which had been developed by

Frank Halford Major Frank Bernard Halford CBE FRAeS (7 March 1894 – 16 April 1955) was an English aircraft engine designer. He is best known for the series of de Havilland Gipsy engines, widely used by light aircraft in the 1920s and 30s. Career Educat ...

from their large stocks of war surplus

Renault Groupe Renault ( , , , also known as the Renault Group in English; legally Renault S.A.) is a French multinational automobile manufacturer established in 1899. The company produces a range of cars and vans, and in the past has manufactured ...

V8 aero engines. The Renault had been renowned for its reliability. De Havilland realised that half of this engine would make an air-cooled four-cylinder inline engine of just the right size and at low cost. He persuaded Halford to undertake its design and development. The cylinders, pistons, con-rods and gearing were taken from the Renault, with the valve gear based on the Airdisco, and a new five-bearing crankshaft and cast crankcase were designed. Developing in normal flight it became the first Cirrus engine, and the first air-cooled four-cylinder inline aero engine, to go into quantity production. The Cirrus was launched onto the market in the

de Havilland Cirrus Moth The de Havilland DH.60 Moth is a 1920s British two-seat touring and training aircraft that was developed into a series of aircraft by the de Havilland Aircraft Company. Development The DH.60 was developed from the larger DH.51 biplane. ...

, first in a long line of Moths, in 1925. The engine proved to be ideal for private light aircraft and it created a new era of private flying in the UK, in both the Cirrus Moth and other similar aircraft. It was simple enough to be understood and looked after by the private owner, while its reliability made private flying safe for the first time. Moreover it achieved these at an affordable cost. The uprated Cirrus II, with slightly greater displacement, delivered from 1926. Halford ended his association with ADC at the end of the year, but development continued. The Cirrus III was introduced in 1928 with even greater displacement and power of .Gunston 1989

Cirrus Aero Engines

As ADC began to run out of the Renault engines in 1928, Cirrus Aero Engines Limited was formed at

Croydon Croydon is a large town in south London, England, south of Charing Cross. Part of the London Borough of Croydon, a local government district of Greater London. It is one of the largest commercial districts in Greater London, with an extensi ...

to manufacture the Cirrus models from scratch. Although Halford was no longer associated with it (having gone off to develop the next-generation but otherwise similar

de Havilland Gipsy The de Havilland Gipsy is a British air-cooled four-cylinder in-line aircraft engine designed by Frank Halford in 1927 to replace the ADC Cirrus in the de Havilland DH.60 Moth light biplane. Initially developed as an upright 5 litre (300 ...

series), the Cirrus company continued to develop new models, with the uprated Hermes appearing in 1929. It had been developed by ADC to provide more power than even the Cirrus III. Overall slightly shorter but with much the same overall weight, it delivered .

American Cirrus Engines (ACE)

American Cirrus Engines, Inc. was a subsidiary of Allied Motor Industries, Inc. set up at Belleville, N.J. in November 1928, initially to manufacture the Cirrus III under license.Stout 1929 Having developed the American Cirrus III engine at New Jersey, the company moved to Marysville, Michigan, where it set up production. The engine was rated at at 2100 revolutions per minute. The company became known as the A.C.E. Corporation.NASM Staff; ''National Air & Space Museum Technical Reference Files: Propulsion'', Smithsonian National Air and Space Museu

/ref> A new range of inverted engines was branded Hi-Drive and appeared under names such as the Hi-Drive Cirrus III and Hi-Drive Ensign. The Hi-Drive was supplied in direct and geared drive options, and was designed to accept a de Palma supercharger for increased performance. In 1935 A.C.E. was taken over by

Menasco The Menasco Motors Company was an American aircraft engine and component manufacturer. History The company was organized by Albert S. Menasco in 1926 to convert World War I surplus Salmson Z-9 water-cooled nine-cylinder radials into air-coole ...

, who developed the inverted engine as the

Pirate Piracy is an act of robbery or criminal violence by ship or boat-borne attackers upon another ship or a coastal area, typically with the goal of stealing cargo and other valuable goods. Those who conduct acts of piracy are called pirates, v ...

, sold from 1936, and a six-cylinder derivative as the

Buccaneer Buccaneers were a kind of privateers or free sailors particular to the Caribbean Sea during the 17th and 18th centuries. First established on northern Hispaniola as early as 1625, their heyday was from Stuart Restoration, the Restoration in 16 ...

Cirrus-Hermes

The independent Cirrus-Hermes Engineering Company was formed in 1931. The Hermes models I, II, III and IV were produced ranging in power from 105 hp to 140 hp depending on type. While the Hermes II and III were uprights like their predecessors, the Hermes II B introduced a major change with the cylinders being inverted for the first time. The resulting high propeller line allowed the top of the engine to be lowered, which significantly improved the pilot's view in a single-engined type. All subsequent models would be inverted.Gunston 1989 By this time C. S. Napier, son of

Montague Napier Montague Stanley Napier (14 April 1870 – 22 January 1931) was an English automobile and aircraft engine manufacturer. His grandfather, David Napier (1785–1873), had moved to London from Scotland and by 1836 had established an engineering comp ...

, had joined as technical director and engine designer. He began work on two new engines but before they could be finished the company came under new management.

Cirrus Hermes

In 1934 the company was taken over by the

Blackburn Aeroplane & Motor Company Blackburn () is an industrial town and the administrative centre of the Blackburn with Darwen borough in Lancashire, England. The town is north of the West Pennine Moors on the southern edge of the Ribble Valley, east of Preston and north- ...

and moved to Brough in Yorkshire. Napier remained technical director and, while he completed the development and initial sales of the Cirrus Minor and

Cirrus Major The Blackburn Cirrus Major is a British, inline-four aircraft engine that was developed in the late 1930s. Design and development The Blackburn Cirrus Major started life as a continued evolution of the original Cirrus and Hermes series of air ...

, Blackburn kept Cirrus Hermes as a separate company (though without the hyphen in its name). Although completely new designs, they were of broadly similar layout to the previous inverted engines, with the Minor in the 70-80 hp class and the Major giving 125 hp in normal use. Coming to the market almost together in 1935, they rationalised and replaced the previous ranges.

Blackburn

Once the new Cirrus engines were established, in 1937 the company became the Cirrus Engine Division of Blackburn, which itself had been incorporated into

Blackburn Aircraft Limited Blackburn () is an industrial town and the administrative centre of the Blackburn with Darwen borough in Lancashire, England. The town is north of the West Pennine Moors on the southern edge of the Ribble Valley, east of Preston and north- ...

. The

Blackburn Cirrus Midget The Blackburn Cirrus Midget was a British four-cylinder, inverted, inline air-cooled aero engine designed and built in 1937 by the Cirrus Engine Section of Blackburn Aircraft Limited Blackburn () is an industrial town and the administrat ...

was a smaller version developed in 1938 but it failed to enter production. During and after WWII Blackburn produced uprated versions of the Cirrus Minor and Major. In 1948 it introduced the

Blackburn Cirrus Bombardier The Blackburn Cirrus Bombardier was a British four-cylinder inline aircraft engine, developed and built by the Blackburn Aircraft company in the mid-1950s. The engine featured fuel injection. Variants ;Cirrus Bombardier 203 :Military version, ...

with fuel injection and a higher compression ratio, giving increased output.Lumsden 2003, p. 130. When Blackburn Aircraft merged with

General Aircraft Limited General Aircraft Limited was a British aircraft manufacturer from its formation in 1931 to amalgamation with Blackburn Aircraft in 1949 to become Blackburn and General. Its main products were military gliders and light transport aircraft. His ...

(GAL) in 1949, becoming Blackburn & General Aircraft Limited, it continued to market the Minor, Major and Bombardier range until the late 1950s.

Variants

Cirrus-Hermes I in Roe IV triplane replica

; Cirrus I :(1925) ;

Cirrus II The ADC Cirrus is a series of British aero engines manufactured using surplus Renault parts by the Aircraft Disposal Company (ADC) in the 1920s. The engines were air-cooled, four-cylinder inline types. They were widely used for private and li ...

:(1926) ;

Cirrus III The ADC Cirrus is a series of British aero engines manufactured using surplus Renault parts by the Aircraft Disposal Company (ADC) in the 1920s. The engines were air-cooled, four-cylinder inline types. They were widely used for private and li ...

:(1929) Introduced by ADC, also manufactured by Cirrus Aero Engines. ;American Cirrus III :(1929) Improved variant of the Cirrus III, built under license. ;American Cirrus Hi-drive :Inverted, with direct and geared drive options. ;Hermes :(1929). Later as Hermes I. Introduced by Cirrus Aero Engines, also manufactured by Cirrus-Hermes. ;Hermes II :(1930). ;Hermes IIB :(1932). First inverted engine ;Hermes III :(1932). Upright ;Hermes IV and IV A :(1930). Inverted. The Hermes IV A with opposite-handed rotation was introduced around 1934. ; Cirrus Minor :(1935). Later as Cirrus Minor I. Inverted. Introduced by Cirrus Hermes, also manufactured by Blackburn. ; Cirrus Minor 100 hp :(1944). Inverted. ; Cirrus Minor II :(1945). Inverted. ;

:(1935). Later as Cirrus Major I. Inverted. Introduced by Cirrus Hermes, also manufactured by Blackburn. ;

150 hp :Inverted. ;

II :(1945). Inverted. ;

III :(1945) Inverted. ;

:(1938). Prototype. Not manufactured. ;

:(1948). Fuel injection.

Applications

''List from Lumsden'' except where noted. The list includes trial installations where a different engine was principally adopted.

Cirrus

Cirrus I

Avro Avian The Avro Avian was a series of British light aircraft designed and built by Avro in the 1920s and 1930s. While the various versions of the Avian were sound aircraft, they were comprehensively outsold by the de Havilland Moth and its descendants ...

Avro Baby The Avro 534 Baby (originally named the "Popular") was a British single-seat light sporting biplane built shortly after the First World War. Development The Avro Baby was a single-bay biplane of conventional configuration with a wire-braced wo ...

de Havilland DH.60 Moth The de Havilland DH.60 Moth is a 1920s British two-seat touring and training aircraft that was developed into a series of aircraft by the de Havilland Aircraft Company. Development The DH.60 was developed from the larger DH.51 biplane. ...

Short Mussel The Short S.7 Mussel was a single-engined two-seat monoplane built by Short Brothers to test the performance of their duralumin monocoque floats. Two were built. Development Having demonstrated the watertightness and corrosion resistance of du ...

* Westland Widgeon

Cirrus II

* de Havilland DH.71 Tiger Moth * Piaggio P.9 *

* Westland Widgeon * Bloudek XV Lojze

Cirrus III

Blackburn Bluebird The Blackburn L.1 Bluebird was a British single-engine biplane light trainer/tourer with side-by-side seating, built in small numbers by Blackburn Aircraft in the 1920s. Design and development The Bluebird L.1 was initially designed as a co ...

Cierva C.17 The Cierva C.17 was a British experimental autogyro built by Cierva Autogiro Company in England in 1928, in association with Avro (which designated it their Type 612). It was an attempt to build upon the successful Cierva C.8 design using the ...

* de Havilland DH.71 Tiger Moth * Dudley Watt D.W.2 * Koolhoven FK.41 * Klemm L.26 * Klemm L.27 *

Simmonds Spartan The Simmonds Spartan is a 1920s British two-seat biplane trainer/tourer aircraft built by Simmonds Aircraft Limited. History Not happy with the high cost of manufacturing light aircraft, O.E. Simmonds designed and built a wooden two-seat bip ...

Spartan Arrow The Spartan Arrow is a British two-seat biplane aircraft of the early 1930s, built by Spartan Aircraft Limited. History Built as a successor to the company's first design the Simmonds Spartan, the Arrow was a two-seat biplane with a spruce ...

Westland Wessex The Westland Wessex is a British-built turbine-powered development of the Sikorsky H-34 (in US service known as Choctaw). It was developed and produced under licence by Westland Aircraft (later Westland Helicopters). One of the main changes ...

* Westland Widgeon

Cirrus IIIA

* Miles M.2 Hawk

American Cirrus Engines

Cirrus III

* Great Lakes 2T-1A *

Emsco B-4 Cirrus The Emsco B-4 Cirrus was a mid-wing, two-seat trainer built in the US in the late 1920s. Six were built and three variants with more powerful engines flown. Design The two-seat B-4 trainer was a mid-wing monoplane with wings of rectangular p ...

Fairchild 24 The Fairchild Model 24, also called the Fairchild Model 24 Argus and UC-61 Forwarder, is a four-seat, single-engine monoplane light transport aircraft designed by the Fairchild Aviation Corporation in the 1930s. It was adopted by the United Sta ...

Cirrus Hi-Drive

* Fairchild 22 C7A, C7AM and C7AS * Fairchild 24 C8 *

Granville Gee Bee Sportster The Gee Bee Sportster was a family of sports aircraft built in the United States in the early 1930s by the Granville Brothers. They were low-wing strut- and wire-braced monoplanes of conventional, if short-coupled, design, with open cockpits and f ...

Models X and B * Great Lakes 2T-1 and -1E * Skylark Aircraft 3-95

Hermes

Hermes I

* Desoutter I * Koolhoven FK.41 * Koolhoven FK.42 *

Hawker Tomtit The Hawker Tomtit is a British training biplane from the late 1920s. Design and development The Royal Air Force in 1927 required a replacement for their current elementary trainers, the elderly Avro 504Ns. They specified that the power plant sh ...

Hendy 302 __NOTOC__ The Hendy 302 was a British two-seat cabin monoplane designed by Basil B. Henderson and built by Parnall, George Parnall & Company Limited at Yate in 1929. Only one aircraft was built registered ''G-AAVT''. The 302 was a low-wing cant ...

Parnall Elf The Parnall Elf is a British two seat light touring aircraft of the 1920s. Built by Parnall, George Parnall & Co. the Elf was the last aircraft designed by Harold Bolas before he left the company to go to the United States. Design and develop ...

Saro Cutty Sark The Saro A17 Cutty Sark was a British amphibious aircraft from the period between World War I and World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 194 ...

Southern Martlet The Southern Martlet was a single-engined, single-seat biplane sports aircraft. Six were built, including the rather different and unsuccessful Metal Martlet. Design and development The Southern Martlet was the first aircraft designed by tea ...

* Westland Widgeon

Hermes II

* Desoutter I *

* Spartan Three-Seater * Westland Widgeon

Hermes IIB

Arrow Active The Arrow Active is a British aerobatic aircraft built in the 1930s. Design and development The Arrow Active is a single-seat biplane of conventional configuration, with single-bay, staggered wings of unequal span and chord, bordering on being ...

BFW M.23 The BFW M.23, sometimes known as the Messerschmitt M 23, was a 1920s two-seat sporting aircraft designed by Willy Messerschmitt, and produced by ''Bayerische Flugzeugwerke'' (BFW). Examples won several prestigious races in 1929 and 1930. Develo ...

* Klemm L.27 * Koolhoven F.K.44 * Koolhoven F.K.45Wesselink 1982 p.81 * Spartan Three-Seater

Hermes IV

* Avro 643 Cadet *

* Miles M.2 Hawk *

Percival Gull The Percival Gull was a British single-engined monoplane, first flown in 1932. It was successful as a fast company transport, racing aircraft and long-range record breaker. It was developed into the Vega Gull and the Proctor. Design and devel ...

* Roe IV Triplane replica *

Spartan Cruiser The Spartan Cruiser was a 1930s British three- engined transport monoplane for 6 to 10 passengers built by Spartan Aircraft Limited at East Cowes, Isle of Wight. It was a development of the Saro-Percival Mailplane for passenger use. Design an ...

* Spartan Three-Seater

Hermes IVA

Avro Club Cadet The Avro Club Cadet was a 1930s single-engined British biplane trainer aircraft, designed and built by Avro as a development of the earlier Cadet. It was planned for private and club use and, unlike the Cadet, was fitted with folding wings. ...

Blackburn B-2 The Blackburn B-2 was a biplane side-by-side trainer aircraft designed and produced by the British aviation manufacturer Blackburn Aircraft. It was designed as a successor to the Bluebird IV and was derived from it, thus the two aircraft sha ...

Blackburn Segrave The Blackburn B-1 Segrave was a 1930s British twin-engine four-seat touring aircraft built by Blackburn Aircraft. History The aircraft was designed by the racing driver (and world land speed record holder) Sir Henry Segrave as a twin-engin ...

Engines on display

*A preserved ADC Cirrus II is on display at the

Science Museum (London) The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and is one of the city's major tourist attractions, attracting 3.3 million visitors annually in 2019. Like other publicly funded ...

. *A Cirrus Hermes is on display at the

EAA AirVenture Museum The EAA Aviation Museum, formerly the EAA AirVenture Museum (or Air Adventure Museum), is a museum dedicated to the preservation and display of historic and experimental aircraft as well as antiques, classics, and warbirds. The museum is lo ...

Oshkosh, Wisconsin Oshkosh is a city in Winnebago County, Wisconsin, of which it is the county seat. The city had a population of 66,816 in 2020, making it the ninth-largest city in Wisconsin. It is also adjacent to the Town of Oshkosh. History Oshkosh was ...

References

Notes

Bibliography

* The Aviation Ancestry Database of British Aviation Advertisements 1909-1990
Cirrus advertisements
(retrieved 23 April 2020). * Gunston, Bill. ''World Encyclopaedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989. * * * Lumsden, Alec. ''British Piston Engines and their Aircraft''. Marlborough, Wiltshire: Airlife Publishing, 2003. . *R. Cheyne Stout; "The Development of the Cirrus Engine", ''U.S. Air Services'', Volume 14, Number 4, April 1929. pp.53-4. * Taylor, Douglas R. ''Boxkite to Jet: The Remarkable Career of Frank B. Halford''. Rolls-Royce Heritage Trust. 1999. . *

External links

{{DEFAULTSORT:Cirrus aero engines 1920s aircraft piston engines 1930s aircraft piston engines 1940s aircraft piston engines 1950s aircraft piston engines

Cirrus Cirrus may refer to: Science *Cirrus (biology), any of various thin, thread-like structures on the body of an animal *Cirrus (botany), a tendril *Infrared cirrus, in astronomy, filamentary structures seen in infrared light *Cirrus cloud, a type ...

Design and development

ADC

Cirrus Aero Engines

American Cirrus Engines (ACE)

Cirrus-Hermes

Cirrus Hermes

Blackburn

Variants

Applications

Cirrus

Cirrus I

Cirrus II

Cirrus III

Cirrus IIIA

American Cirrus Engines

Cirrus III

Cirrus Hi-Drive

Hermes

Hermes I

Hermes II

Hermes IIB

Hermes IV

Hermes IVA

Engines on display

See also

References

Notes

Bibliography

External links