Harry Ricardo

Harry Ricardo
Born Henry Ralph Ricardo
(1885-01-26)26 January 1885
London, England
Died 18 May 1974(1974-05-18) (aged 89)
Nationality British
Education Rugby School
Trinity College, Cambridge
Spouse(s) Beatrice Bertha Hale
Children 3 daughters
Parent(s) Halsey Ralph Ricardo
Catherine Jane Ricardo

Engineering career


Institution of Mechanical Engineers

Royal Aircraft Establishment

Mk V tank engine

Citroen Rosalie diesel engine

Turbulent Head gasoline combustion system

Comet diesel combustion system

Rolls-Royce Crecy
Rolls-Royce Merlin
Significant advance

Diesel and Spark Ignition combustion systems

Aero engines
Awards KBE
Fellow of the Royal Society[1]

Sir Henry Ralph "Harry" Ricardo (26 January 1885 – 18 May 1974) was one of the foremost engine designers and researchers in the early years of the development of the internal combustion engine.

Among his many other works, he improved the engines that were used in the first tanks, oversaw the research into the physics of internal combustion that led to the use of octane ratings, was instrumental in development of the sleeve valve engine design, and invented the Diesel "Comet" Swirl chamber that made high-speed diesel engines economically feasible.

Early life

Blue plaque, 13 Bedford Square, London

Harry Ricardo was born at 13 Bedford Square, London in 1885, the eldest of three children, and only son of Halsey Ricardo, the architect, and his wife Catherine Jane, daughter of Sir Alexander Meadows Rendel, a civil engineer. Ricardo was descended from a brother of the famous political economist David Ricardo, a Sephardi Jew of Portuguese origin (hence the last name). He was one of the first people in England to see an automobile when his grandfather purchased one in 1898. He was from a relatively wealthy family and educated at Rugby School. In October 1903 he joined Trinity College, Cambridge as a civil engineering student. Ricardo had been using tools and building engines since the age of ten.[2]


In 1911 Ricardo married Beatrice Bertha Hale, an art student at the Slade School of Art, in London. Her father, Charles Bowdich Hale, was the Ricardos' family doctor. They had three daughters, and lived most of their married life at Lancing and Edburton in West Sussex.[2]

Car engines

In 1904, at the end of his first year at Cambridge, he decided to enter the University Automobile Club's event, which was a competition to design a machine that could travel the furthest on 1 imp qt (1.14 l) of petrol. His engine had a single cylinder, and was the heaviest entered, but his motorcycle design won the competition, having covered a distance of 40 miles (64 km). He was then persuaded to join the Professor of Mechanism and Applied Mechanics, Bertram Hopkinson, working on research into engine performance. He graduated with a degree in 1906 and spent another year researching at Cambridge.[2]

Ricardo is said by Percy Kidner, then Co-managing director of Vauxhall, to have had a hand in the design of the Vauxhall engine designed by Laurence Pomeroy for the RAC 2,000 miles (3,200 km) trial of 1908.[3]

Before graduation, Ricardo had designed a two-stroke motorcycle engine to study the effect of mixture strength upon the combustion process. When he graduated, the small firm of Messrs Lloyd and Plaister expressed interest in making the engine. Ricardo produced designs for two sizes, and the smaller one sold about 50 engines until 1914, when the war halted production.[4]

In 1909 he designed a two-stroke 3.3-litre engine, for his cousin Ralph Ricardo, who had established a small car manufacturing company, "Two Stroke Engine Company", at Shoreham-by-Sea. The engine was to be used in the Dolphin car.[5] The cars were well made, but it became apparent that they cost more to make than the selling price. The company fared better making two-stroke engines for fishing boats. In 1911 the firm collapsed and Ralph departed for India. Ricardo continued to design engines for small electric lighting sets; these were produced by two companies until 1914.[4]

Tank engines

In 1915 Ricardo set up a new company, "Engine Patents Ltd.", which developed the engine that would eventually be used in the first successful tank design, the British Mark V. The Daimler sleeve-valve engine used in the Mark I created copious amounts of smoke, which easily gave away its position. Ricardo was asked to look at the problem of reducing smoky exhaust gases and decided that a new engine was needed. Existing companies were able to undertake construction of such an engine but not the design, so Ricardo designed it himself. As well as having reduced smoke emissions, the new engine was much more powerful than the existing ones. The new six-cylinder engine produced 150 hp (110 kW), compared with 105 hp (78 kW), and later modifications produced 225 hp (168 kW) and 260 hp (190 kW) By April 1917 one hundred engines were being produced a week. A total of over 8,000 of his tank engines were put into military service, making it the first British-designed engine to be produced in large numbers. The Mark IX tank, as well as the British version of the Mark VIII, also used a Ricardo engine. In addition to being fitted to tanks, several hundred of the 150 hp (110 kW) engines were used in France for providing power and light to base workshops, hospitals, camps, etc.[6]

Aircraft engines

In 1917 his old mentor, Bertram Hopkinson, who was now Technical Director at the Air Ministry, invited him to join the new engine research facility at the Department of Military Aeronautics, later to become the RAE. In 1918 Hopkinson was killed while flying a Bristol Fighter, and Ricardo took over his position. From that point on the department produced a string of experimental engines and research reports that constantly drove the British, and world, engine industry.[7]

One of his first major research projects was on the problems of irregular combustion, known as knocking or pinking. To study the problem he built a unique variable-compression test engine. This led to the development of an octane rating system for fuels, and considerable investment into octane improving additives and refining systems. The dramatic reduction in fuel use as a result of higher-octane fuel was directly responsible for allowing Alcock and Brown to fly the Atlantic in their Vickers Vimy bombers adapted with his modifications.[8]

Advances in engine design

Side valve engine with Ricardo's turbulent head

In 1919 Ricardo was studying the phenomena affecting the combustion within the petrol engine and the diesel engine. He realised that turbulence within the combustion chamber increased flame speed, and that he could achieve this by offsetting the cylinder head. He also realised that making the chamber as compact as possible would reduce the distance that the flame had to travel and would reduce the likelihood of detonation. He later developed the induction swirl chamber, which was an attempt to achieve orderly air motion in a diesel engine, the swirl being initiated by inclined ports and accentuated by forcing the air into a small cylindrical volume. Finally he developed the compression swirl chamber for diesel engines. This design embodied intense swirl with a reasonable rate of pressure rise and good fuel consumption.[9]

The compression swirl chamber design was called a "Comet" design (patented in 1931) and was subsequently licensed to a large number of companies for use in trucks, buses, tractors and cranes, as well as private cars and taxis. A Comet combustion chamber was used in the first Associated Equipment Company (AEC) diesel buses operated in 1931 by London General Omnibus Co, later part of the London Passenger Transport Board/London Transport. A later development of it featured in the world's first volume production diesel passenger car, the 1934 Citroën Rosalie. This meant that Britain led the world in the field of high-speed diesels for road transport at that time. This advantage was lost to the United Kingdom as a result of the heavy tax imposed on diesel fuel in the budget of 1938.[9]

Ricardo designed the 1921 T.T. Vauxhall engine which was described by Cecil Clutton in Motor Sport as a tour de force[10] in the 1922 RAC T. T. O Payne in the Ricardo Vauxhall came 3rd, Jean Chassagne on a 1921 Grand Prix Sunbeam winning outright.[11] The engine was later developed by Mays and Villiers, who fitted a supercharger, and was still a winner fifteen years later.[12]

In 1922 and 1923 Ricardo published a two-volume work "The Internal Combustion Engine".[13]

In 1927 he formed Ricardo Consulting Engineers (now known as Ricardo plc) in Shoreham-by-Sea, which has become one of the foremost automotive consulting firms worldwide and is publicly listed on the London Stock Exchange.

Although Ricardo did not invent the sleeve valve, in 1927, he produced a seminal research paper that outlined the advantages of the sleeve valve, and suggested that poppet valve engines would not be able to offer power outputs much beyond 1500 hp (1,100 kW). A number of sleeve valve aircraft engines were developed following this paper, notably by Napier, Bristol and Rolls-Royce. Bristol produced the Perseus, Hercules, Taurus and the Centaurus, Napier produced the Napier Sabre, and Rolls-Royce produced the Eagle and Crecy, all using sleeve valves.[14]

In 1929 Ricardo was elected Fellow of the Royal Society.[1]

World War II

Ricardo's work on the sleeve valve affected the development of British aircraft engines in the thirties and during the war. He even enhanced the famous Rolls-Royce Merlin engine in the Mosquito by giving it an oxygen enrichment system to improve its performance.[15]

Ricardo's work exerted influence all around the world. While his work guaranteed England a supply of fuels of ever-increasing power during the 1930s, it also helped Germany to develop synthetic high-octane aviation fuel, for example for the Focke-Wulf Fw 190 which inflicted heavy losses among the RAF's Supermarine Spitfires in 1942. Likewise, Ricardo's research on the detonation-inhibiting qualities of water injection was exploited by German engineers (MW 50) to provide their aero-engines with a particularly powerful special emergency power rating.

During 1941–1945 Ricardo was a member of the War Cabinet engineering advisory committee.

Ricardo also assisted in the design of the combustion chambers and fuel control system of Sir Frank Whittle's jet engine.[15]

Post war period

In 1944 Ricardo was elected president of the Institution of Mechanical Engineers. In 1945 he and his wife moved from Shoreham-by-Sea to Graffham, also in West Sussex. In 1948 Ricardo was knighted in recognition for his work in the field of internal combustion engineering.

In 1964 Ricardo retired from active work in Ricardo Consulting Engineers but kept in touch with various engineers within the company.

In 1974, at the age of 89, Ricardo suffered a pelvic injury in a fall. He died six weeks later, on 18 May.[2][16]

Blue plaque on 13 Bedford Square, London

On 16 June 2005 a blue plaque was placed outside the house where he was born in Bedford Square, London. On 1 July 2010, the Institution of Mechanical Engineers bestowed an Engineering Heritage Award on Sir Harry Ricardo in recognition of his life and work as one of the foremost engineers of the twentieth century. The first internal combustion engine which Harry Ricardo designed and built as a schoolboy currently displays this Engineering Heritage plaque in the Ricardo plc company exhibition area. [17]

Ricardo Consulting Engineers (now Ricardo plc)

Main article: Ricardo plc

During the 1960s a second round of development of the Comet system was started, the company now armed with considerably more powerful test apparatus. The refined design was immediately used in many diverse applications, including cars, taxis, buses, trucks, industrial engines, earth-moving equipment, cranes and marine [18] before eventually being superseded by more efficient direct injection systems which are now used in the majority of diesel engines.

In 1978 the US Department of Energy hired Ricardo Consulting to research the Stirling engine as a car engine. A series of engines, eventually forty-five in total, were built to test this system and showed very low emissions, but the efficiency was compromised by the need to operate under transient conditions—the design was best running at a single speed, making it less fesible as a car engine.

In 1986, the Voyager was the first aircraft to fly around the world non-stop and without refuelling. Ricardo Consulting redesigned the otherwise "stock" Teledyne Continental engine to incorporate a highly efficient combustion system and water cooling, thereby dramatically reducing drag and improving fuel economy.

Ricardo worked on spark-ignition engines throughout his career, including pioneering work on direct injection gasoline engines for aircraft engines in the 1930s, but his best-known work was in the development of high-speed diesel engines, in particular for cars. He was responsible for designing the combustion-chamber for the first diesel car engines produced in quantity for the Citroën Rosalie in the mid-thirties. Later, various versions of Ricardo's Comet pre-combustion chamber were deployed in almost all car diesel engines over six decades, up to the mid 1990s, and the Comet remains one of Ricardo's best-known personal achievements in automobile engineering.

Today several stratified charge engines are in use in the automobile market. Stratified charge is a technology that has come of age relatively recently, as a result of advances in manufacturing and electronics, but it was a feature of the first engine that Harry Ricardo built, while still in his teens, in the early years of the 20th century.


See also


  1. 1 2 Hawthorne, W. (1976). "Harry Ralph Ricardo 26 January 1885 -- 18 May 1974". Biographical Memoirs of Fellows of the Royal Society. 22: 358–326. doi:10.1098/rsbm.1976.0016.
  2. 1 2 3 4 Hawthorne, W. (2004). "Ricardo, Sir Harry Ralph (1885–1974)". The Oxford Dictionary of National Biography. doi:10.1093/ref:odnb/31599.
  3. T.R. Nicholson, Sprint – Speed Hillclimbs and Speed Trials in Britain: 1899–1925, David & Charles, 1969, Page 106.
  4. 1 2 Full Text
  5. Motor Sport, October 1968, Page 911.
  6. The Ricardo Exhibition
  7. Harry Ricardo
  8. http://www.oldengine.org/members/diesel/Misc/Ricardo.htm
  9. 1 2 The Ricardo Exhibition
  10. Motor Sport, April 1942, Page 77. See also: Motor Sport, April 1969, Page 350; Motor Sport, July 1969, Page 747.
  11. Kelly, Robert (1966). T. T. Pioneers. The Manx Experience. P.166
  12. S.E. Cummings won the Brighton Speed Trials in the Vauxhall-Villiers in 1936.
  13. The internal-combustion engine by Harry Ralph Ricardo, Blackie and Son Limited.
  14. The Ricardo Exhibition
  15. 1 2 Blue Plaque for Mechanical Engineer Sir Harry Ricardo: Blue Plaques News: Blue Plaques: Research & Conservation: English Heritage
  16. The Guardian, 21 May 1974, Obituary.
  17. Morrison, David (April 2011). Harry Ricardo - A Passion for Efficiency. The Newcomen Society. pp. 153–176. ISBN 978-0-904685-15-2.
  18. Reynolds, John (2008). Engines & Enterprise (Second ed.). Haynes Publishing. ISBN 978 1 84425 516 0.

External links

Wikimedia Commons has media related to Harry Ricardo.
Professional and academic associations
Preceded by
Frederick Charles Lea
President of the Institution of Mechanical Engineers
Succeeded by
Andrew Robertson
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