Napier & Son

From Academic Kids

Napier & Son were a British engine manufacturer and one the most important aircraft engine manufacturers in the early to mid 20th Century. Their post-World War I Lion was the most powerful engine in the world for some time in the 1920s and into the 1930s, and their Sabre design of the early 1940s holds the title for the most powerful piston aircraft engine produced to this day, delivering 3,500 horsepower (2,600 kW) in its later versions.


David Napier and son James founded the company in 1848, and made a wide variety of products including steam-powered printing presses and a centrifuge for sugar manufacturing. After his father's death in 1873, James Napier specialised in beautifully-crafted precision machinery for making coins.

His son Montague Napier inherited the business in 1895 and switched to making motor cars, high-performance luxury cars in particular. Napiers made the first ever six cylinder car, many winning races, and expanded into marine engines as well. Their 1905 boat Napier II set the world marine speed record over a mile at almost 30 knots (56 km/h).

Early in World War I, Napier were contracted to build engines from other companies designs: initially a Royal Aircraft Factory model and then Sunbeams. Both proved to be rather unreliable, and in 1916 Napier decided to design their own instead, an effort that led to the superb W-block 12-cylinder Lion. The Lion was a best-seller for the company, and they eventually abandoned all other products.

In the 1930s the introduction of much larger and more powerful engines from other companies suddenly ended sales of the Lion. Napier quickly started work on newer designs, leading to the 16 cylinder Rapier and the 24 cylinder Dagger, both air-cooled H-block designs. Neither proved very reliable, due to poor cooling of the rearmost cylinders, and even the Dagger's 1,000 hp (750 kW) was already smaller than contemporary designs when it shipped.

Starting from scratch, the Napiers decided to use the new sleeve valve design in a much larger H-block 24-cylinder engine, soon to be known as the Sabre. The engine was very advanced and proved to be difficult to adapt to assembly line efforts, so while the engine was ready for production in 1940, it wasn't until 1944 what production versions were considered reliable. At that point efforts were made to improve it, leading eventually to the Sabre VII delivering 3,500 hp (2,600 kW), making it the most powerful engine in the world, from an engine much smaller than its competition.

Napier also worked on diesel aircraft engines. In the 1930s they licensed the Junkers Jumo 204 for production in England, which they called the Culverin. They also planned on producing a smaller version of the same basic design as the Cutlass, but work on both was cancelled at the outbreak of World War II.

Napier developed a marine engine from the Lion aero engine, the petrol-driven Sea Lion, which could deliver 500 hp and were used in the "Whaleback" Air Sea Rescue Launches.

During the war (1944) Napier were asked by the Royal Navy to supply a diesel engine for use in their patrol boats, but the Culverin's 720 hp (537 kW) was not nearly enough for their needs. Napier then designed the Deltic, essentially three Culverins arranged in a large triangle (deltoid). Considered one of the most complex engine designs of its day, the Deltic was nevertheless very reliable, and was taken into service after the war as a locomotive powerplant (in British Rail's Class 55) in addition to the torpedo boats, minesweepers and other small naval vessels for which it was designed.

Last of the great Napier engines was the Nomad, a "turbo-compound" design that combined a diesel engine with a turbine to recover energy otherwise lost in the exhaust. The advantage to this "odd" design was fuel economy, it had the best specific fuel consumption of any aircraft engine built, even to this day. However even better fuel economy could be had by flying a normal jet engine at much higher altitudes, while existing designs filled the "low end" of the market fairly well. The Nomad was largely ignored by the market, and eventually cancelled.

Along with every other engine company in the post-war era, Napier turned to jet engine designs. Deciding to attack the only market not yet wrapped up by the larger vendors, Napier started the design of a number of turboprop designs which saw some use, notably in helicopters. Their first design, the Napier Naiad and Double Naiad were intended for various Royal Navy Fleet Air Arm designs, but saw no use in the end. Smaller models, the 3,000hp-class Napier Eland and 1,500hp-class Napier Gazelle did somewhat better, notably the Gazelle which powered several models of the popular Westland Wessex helicopter.

Today Napier is no longer in the engine business, with the ending of the Deltic sales in the 1960s they had no new modern designs to offer. They continue on today as a primary supplier of turbochargers, which can be found on many engines.

Lists of Aircraft | Aircraft manufacturers | Aircraft engines | Aircraft engine manufacturers

Airports | Airlines | Air forces | Aircraft weapons | Missiles | Timeline of aviation

External links


Academic Kids Menu

  • Art and Cultures
    • Art (
    • Architecture (
    • Cultures (
    • Music (
    • Musical Instruments (
  • Biographies (
  • Clipart (
  • Geography (
    • Countries of the World (
    • Maps (
    • Flags (
    • Continents (
  • History (
    • Ancient Civilizations (
    • Industrial Revolution (
    • Middle Ages (
    • Prehistory (
    • Renaissance (
    • Timelines (
    • United States (
    • Wars (
    • World History (
  • Human Body (
  • Mathematics (
  • Reference (
  • Science (
    • Animals (
    • Aviation (
    • Dinosaurs (
    • Earth (
    • Inventions (
    • Physical Science (
    • Plants (
    • Scientists (
  • Social Studies (
    • Anthropology (
    • Economics (
    • Government (
    • Religion (
    • Holidays (
  • Space and Astronomy
    • Solar System (
    • Planets (
  • Sports (
  • Timelines (
  • Weather (
  • US States (


  • Home Page (
  • Contact Us (

  • Clip Art (
Personal tools