Napier Lion

Last updated

Lion
CASM - Napier Lion II - 030906.jpg
Napier Lion II at Canada Aviation Museum
Type Piston aero-engine
Manufacturer D. Napier & Son
First run1917
Major applications Handley Page Hyderabad
Vickers Vernon

The Napier Lion is a 12-cylinder, petrol-fueled 'broad arrow' W12 configuration aircraft engine built by D. Napier & Son from 1917 until the 1930s. A number of advanced features made it the most powerful engine of its day and kept it in production long after other contemporary designs had been superseded. It is particularly well known for its use in a number of racing designs, for aircraft, boats and cars.

Contents

Design and development

Early in the First World War, Napier were contracted to build aero engines to designs from other companies, initially a Royal Aircraft Factory model and then Sunbeams. Both engines proved to be unreliable and in 1916 Napier decided to design an engine with high power, light weight and low frontal area. Napier's engineers laid out the engine with its 12 cylinders in what they called a "broad arrow"—three banks of four cylinders sharing a common crankshaft. The configuration is also known as a W engine. [1] The engine was also advanced in form, the heads using four valves per cylinder with twin overhead camshafts on each bank of cylinders and a single block being milled from aluminium instead of the common separate-cylinder steel construction used on almost all other designs.

Cutaway view showing the double overhead camshaft arrangement Napier Lion cambox.jpg
Cutaway view showing the double overhead camshaft arrangement

Under Arthur Rowledge, the design of the engine, renamed Lion, was completed in 1917; hand-built prototypes ran later that year. It was fitted to an Airco DH.9 in early 1918, and many cooling problems were observed during testing. The milled block was difficult to build with the required accuracy and the design reverted to separate aluminium cylinders. Both problems were solved by the middle of the year and the engine entered production in June 1918. The first Lion I versions delivered 450 horsepower (340 kW) from their 24 litres. The power output made the Lion the most powerful Allied aircraft engine, which had previously been the Liberty L-12, producing 400 horsepower (300 kW).

As the most powerful engine available (particularly after a turbocharger became an option in 1922), the Lion went on to commercial success. Through the years between the wars the Lion was ubiquitous and Napier manufactured little else. They stopped making cars in 1925 and little thought was given to replacing their world-famous product. Between the wars the Lion engine powered over 160 different aircraft types.

The Napier Lion installed in the Napier-Railton car Napier-Railton Engine Bay.jpg
The Napier Lion installed in the Napier-Railton car

In highly tuned racing versions, the engine could reach 1,300 hp (970 kW) and it was used to break many world height, air speed and distance records in aircraft and boats, delivering 1,375 hp (1,025 kW) in a highly tuned Lion for a water speed record of 100 mph (160 km/h) in 1933. In land speed records, Lion engines powered many of Sir Malcolm Campbell's record breakers including a record of over 250 mph (400 km/h) in 1932 and John Cobb's 394 mph (634 km/h) Railton Mobil Special in 1947—a record that came well after the Lion had passed its prime and stood until the 1960s. The record had been held by British drivers for 32 years. Lions powered successful entrants in the most prestigious event in air racing, the Schneider Trophy, in 1922 and 1927 but were dropped by Supermarine in favour of a new engine, the Rolls-Royce R, which had been designed for racing.

During the 1930s a new generation of much larger and more powerful engines appeared and the Lion became uncompetitive. By the time the Bristol Hercules and the Rolls-Royce Merlin arrived in the late 1930s, the Lion was obsolete. The Sea Lion, a marine version of the Lion, was used to power high speed RAF Rescue Launches. The Lion aero engine was also adapted to power propeller-driven motor sleighs, which were used for high-speed transport and SAR duties on sea ice by the Finnish Air Force and Navy.

Turning away from the broad arrow layout, Napier designed new engines using the more compact H engine layout. The 16-cylinder Napier Rapier produced 400 hp (300 kW) and the 24-cylinder Napier Dagger delivered just under 1,000 hp (750 kW). The engines were smaller than contemporary designs from other companies and Napier started afresh with a new sleeve valve design, which evolved into the Napier Sabre.

Variants

Lion models [2] [3]
ModelDateWorks No.PowerNotesNotable uses
I1918450 bhp (340 kW) at 1,950 rpmgeared, also related IA and 1AY
II1919E64480 bhp (360 kW) at 2,200 rpm
IIIgeared high compression Vickers Vernon Mk.III
IVexperimental geared Gloster Gorcock
V470 bhp (350 kW) at 2,000 rpm
500 bhp (370 kW) at 2,250 rpm
VA had increased CR to 5.8Mainstay engine of the RAF in the late 1920s, replaced by Lion XI
VSE79Turbocharged, intercooled
VIS1927Turbocharged Gloster Guan
VII1925700 bhp (520 kW) (racing) Gloster III (Schneider Trophy entrant)
Supermarine S.4
VIIA1927E86900 bhp (670 kW) (racing) Golden Arrow
Blue Bird (1927)
Miss England I
Supermarine S.5
Gloster IV
VIIB1927875 bhp (652 kW) (racing)geared Supermarine S.5
Gloster IV
VIID1929E911,350 bhp (1,010 kW) at 3,600 rpm (racing)Supercharged, about 6–8 built Blue Bird (1931)
Fred H Stewart's Enterprise
Betty Carstairs' Estelle V powerboat
Miss Britain III
Gloster VI (Schneider Trophy entrant)
Railton Special (John Cobb's land speed record car)
VIII1927direct drive Gloster Gorcock
XIA1928580 bhp (430 kW) at 2,585 rpm, 6:1 CRRAF production model Napier-Railton
LionessE71Inverted layout, for better visibility. At least some were built turbocharged, for racing.
Sea Lion1933500 and 600 bhp (370 and 450 kW)Marine version of Lion XI British Power Boat Company Type Two 63 ft HSL

Applications

Aircraft

Napier Lion at Brooklands Motor Museum Napier Lion W12 @ Brooklands Museum.JPG
Napier Lion at Brooklands Motor Museum

Other applications

Engines on display

Napier Lion on display at Imperial War Museum Duxford Napier Lion duxford.JPG
Napier Lion on display at Imperial War Museum Duxford

Preserved Napier Lion engines are on static display at

Specifications (Lion II)

Data from Lumsden [7]

General characteristics

Components

Performance

See also

Comparable engines

Related lists

Related Research Articles

<span class="mw-page-title-main">Bristol Jupiter</span> British nine-cylinder radial engine family

The Bristol Jupiter is a British nine-cylinder single-row piston radial engine that was built by the Bristol Aeroplane Company. Originally designed late in World War I and known as the Cosmos Jupiter, a lengthy series of upgrades and developments turned it into one of the finest engines of its era.

<span class="mw-page-title-main">Bristol Pegasus</span> Radial aero engine

The Bristol Pegasus is a British nine-cylinder, single-row, air-cooled radial aero engine. Designed by Roy Fedden of the Bristol Aeroplane Company, it was used to power both civil and military aircraft of the 1930s and 1940s. Developed from the earlier Mercury and Jupiter engines, later variants could produce 1,000 horsepower from its capacity of 1,750 cubic inches by use of a geared supercharger.

<span class="mw-page-title-main">Bristol Perseus</span> 1930s British piston aircraft engine

The Bristol Perseus was a British nine-cylinder, single-row, air-cooled radial aircraft engine produced by the Bristol Engine Company starting in 1932. It was the first production sleeve valve aero engine.

<span class="mw-page-title-main">Napier Sabre</span> 1930s British aircraft piston engine

The Napier Sabre is a British H-24-cylinder, liquid-cooled, sleeve valve, piston aero engine, designed by Major Frank Halford and built by D. Napier & Son during World War II. The engine evolved to become one of the most powerful inline piston aircraft engines in the world, developing from 2,200 hp (1,600 kW) in its earlier versions to 3,500 hp (2,600 kW) in late-model prototypes.

<span class="mw-page-title-main">Bristol Hercules</span> Radial aircraft engine by Bristol Engine Company

The Bristol Hercules is a 14-cylinder two-row radial aircraft engine designed by Sir Roy Fedden and produced by the Bristol Engine Company starting in 1939. It was the most numerous of their single sleeve valve designs, powering many aircraft in the mid-World War II timeframe.

<span class="mw-page-title-main">D. Napier & Son</span> British engineering company

D. Napier & Son Limited was a British engineering company best known for its luxury motor cars in the Edwardian era and for its aero engines throughout the early to mid-20th century.

de Havilland Gipsy Major 1930s British piston aircraft engine

The de Havilland Gipsy Major or Gipsy IIIA is a four-cylinder, air-cooled, inverted inline engine used in a variety of light aircraft produced in the 1930s, including the famous Tiger Moth biplane. Many Gipsy Major engines still power vintage aircraft types.

<span class="mw-page-title-main">Rolls-Royce Vulture</span> 1930s British piston aircraft engine

The Rolls-Royce Vulture was a British aero engine developed shortly before World War II that was designed and built by Rolls-Royce Limited. The Vulture used the unusual "X-24" configuration, whereby four cylinder blocks derived from the Rolls-Royce Peregrine were joined by a common crankshaft supported by a single crankcase. The engine was originally designed to produce around 1,750 horsepower (1,300 kW) but problems with the Vulture design meant that the engines were derated to around 1,450 to 1,550 hp in service by limiting the maximum rpm.

<span class="mw-page-title-main">Rolls-Royce Griffon</span> 1930s British piston aircraft engine

The Rolls-Royce Griffon is a British 37-litre capacity, 60-degree V-12, liquid-cooled aero engine designed and built by Rolls-Royce Limited. In keeping with company convention, the Griffon was named after a bird of prey, in this case the griffon vulture.

<span class="mw-page-title-main">Rolls-Royce Kestrel</span> Aircraft engine from Rolls-Royce

The Rolls-Royce Kestrel is a 21.25 litre V-12 aircraft engine from Rolls-Royce. It was their first cast-block engine, and used as the pattern for most of their future piston-engine designs. Used during the interwar period, it was fitted to a number of British fighters and bombers of the era, including the Hawker Fury and Hawker Hart family, and the Handley Page Heyford. The Kestrel engine was also sold to international air force customers; in this role it was used to power prototypes of the German Messerschmitt Bf 109 and the Junkers Ju 87 "Stuka" dive-bomber, as the Junkers Jumo 210 engines were not ready to be fitted. Several examples of the Kestrel engine remain airworthy today.

<span class="mw-page-title-main">Rolls-Royce Eagle</span> 12-cylinder vee liquid cooled aircraft engine

The Rolls-Royce Eagle was the first aircraft engine to be developed by Rolls-Royce Limited. Introduced in 1915 to meet British military requirements during World War I, it was used to power the Handley Page Type O bombers and a number of other military aircraft.

<span class="mw-page-title-main">Rolls-Royce Falcon</span>

The Rolls-Royce Falcon is an aero engine developed in 1915. It was a smaller version of the Rolls-Royce Eagle, a liquid-cooled V-12 of 867 cu in capacity. Fitted to many British World War I-era aircraft, production ceased in 1927. The Falcon was designed by R.W. Harvey-Bailey.

<span class="mw-page-title-main">Rolls-Royce Goshawk</span> 1930s British piston aircraft engine

The Rolls-Royce Goshawk was a development of the Rolls-Royce Kestrel that used evaporative or steam cooling. In line with Rolls-Royce convention of naming piston engines after birds of prey, it was named after the goshawk.

<span class="mw-page-title-main">Armstrong Siddeley Jaguar</span> 1920s British piston aircraft engine

The Armstrong Siddeley Jaguar is an aircraft engine developed by Armstrong Siddeley. The Jaguar was a petrol-fuelled air-cooled 14-cylinder two-row radial engine design. The Jaguar III was first used in 1923, followed in 1925 by the Jaguar IV and in 1927 by the Jaguar VI. In 1925 the Jaguar became the first production aero engine incorporating a geared supercharger.

<span class="mw-page-title-main">Armstrong Siddeley Mongoose</span> 1920s British piston aircraft engine

The Armstrong Siddeley Mongoose is a British five-cylinder radial aero engine produced by Armstrong Siddeley. Developed in the mid-1920s it was used in the Hawker Tomtit trainer and Parnall Peto seaplane amongst others. With a displacement of 540 cubic inches (9 litres) the Mongoose had a maximum power output of 155 horsepower (115 kilowatts).

<span class="mw-page-title-main">Bristol Lucifer</span> 1910s British piston aircraft engine

The Bristol Lucifer was a British three-cylinder, air-cooled, radial engine for aircraft. Built in the UK in the 1920s by the Bristol Aeroplane Company, it produced 100 horsepower (75 kW).

<span class="mw-page-title-main">Avro 571 Buffalo</span>

The Avro 571 Buffalo was a prototype British carrier-based torpedo bomber biplane, designed and built by Avro in the 1920s. It was not selected for service, the Blackburn Ripon being ordered instead.

<span class="mw-page-title-main">Napier Dagger</span> 1930s British aircraft piston engine

The Napier Dagger was a 24-cylinder H-pattern (or H-Block) air-cooled engine designed by Frank Halford and built by Napier before World War II. It was a development of the earlier Napier Rapier.

<span class="mw-page-title-main">Blackburne Thrush</span> 1920s British aircraft piston engine

The Blackburne Thrush was a 1,500 cc three-cylinder radial aero-engine for light aircraft produced by Burney and Blackburne Limited. Burney and Blackburne were based at Bookham, Surrey, England and was a former motorcycle manufacturer.

<span class="mw-page-title-main">Parnall Possum</span> Type of aircraft

The Parnall Possum was an experimental triplane with a single, central engine driving wing-mounted propellers via shafts and gears. Two of these British aircraft were built in the mid-1920s.

References

Notes

  1. Domonoske, Arthur Boquer; Finch, Volney Cecil (1936). Aircraft Engines: Theory, Analysis, Design and Operation (Engineering textbook). J. Wiley & Sons. p. 7. The W, or broad arrow engine, has three rows of cylinders of which the central row is vertical with the other two rows forming equal angles with the vertical.
  2. Vessey 1997
  3. "Napier Aero-Engines". Flight . 73 (2579): 893. 27 June 1958.
  4. Ransom and Fairclough, S and R (1987). "English Electric Aircraft and their Predecessors". Their Fighting Machines. Putnam. Retrieved 7 January 2017.
  5. 2nd MTB Flotilla.pdf [ permanent dead link ]
  6. "Miss Britain III – National Maritime Museum". Collections.rmg.co.uk. Retrieved 6 March 2013.
  7. Lumsden 2003, p.166.

Bibliography

  • Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN   1-85310-294-6.
  • Vessey, Alan. Napier Powered. Stroud: Tempus (Images of England series), 1997. ISBN   0-7524-0766-X.