The X-24 is one of the few configurations of X-type engines known to have been produced. The design consists of four banks of six cylinders with a common crankshaft. This is lighter than other multi-bank designs, which require multiple crankshafts. Few of the X-24 engines developed saw service, and their production lifetimes were very limited. Postwar developments of the

turbojet The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...

and

turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which ac ...

engines obviated the need for large piston aircraft engines of this type. In the United Kingdom,

Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...

produced the

Vulture A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture (including Condors). Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and ...

X-24 based on the Peregrine (which was itself a highly developed

Kestrel The term kestrel (from french: crécerelle, derivative from , i.e. ratchet) is the common name given to several species of predatory birds from the falcon genus ''Falco''. Kestrels are most easily distinguished by their typical hunting behaviour ...

). The Peregrine proved troublesome, and the Vulture inherited many of the Peregrine's problems, as well as some of its own, and proved unsuccessful. The company also developed the smaller

Exe Exe or EXE may refer to: * .exe, a file extension * exe., abbreviation for executive Places * River Exe, in England * Exe Estuary, in England * Exe Island, in Exeter, England Transportation and vehicles * Exe (locomotive), a British locomotive ...

of for use in naval aircraft. Development work on all these engines ended in 1941 as Rolls-Royce concentrated on the Griffon and

Merlin Merlin ( cy, Myrddin, kw, Marzhin, br, Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a mage, with several other main roles. His usual depiction, based on an amalgamation of historic and le ...

. In

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

, the development of the Isotta Fraschini Zeta R.C. 24/60 of was curtailed due to the Italian armistice. Meanwhile, in Germany, the substantially larger

Daimler-Benz DB 604 The Daimler-Benz DB 604 was an experimental German 24-cylinder aircraft engine, which did not progress beyond the initial engine testing phase and was ultimately abandoned in 1942. Design and development The DB 604 was unique among the DB 600 ...

, intended for use in the

Bomber B Bomber B was a German military aircraft design competition organised just before the start of World War II to develop a second-generation high-speed bomber for the ''Luftwaffe''. The new designs would be a direct successor to the ''Schnellbombe ...

program, was cancelled on instructions from the RLM in 1942. In the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

the large ( or wide) Dobrotvorskiy MB-100 was developed in 1942 and mounted on a

Yermolayev Yer-2 The Yermolayev Yer-2 (russian: Ермолаев Ер-2) was a long-range Soviet medium bomber used during World War II. It was developed from the Bartini Stal-7 prototype airliner before the war. It was used to bomb Berlin from airbases in Eston ...

bomber. The construction was based on duplication of

Klimov VK-105 The Klimov M-105 was a V12 liquid-cooled piston aircraft engine used by Soviet aircraft during World War II.Gunston 1989, p. 90 Development The M-105, designed in 1940, drew heavily on Klimov's experience with the Hispano-Suiza 12Y (license-bui ...

V-12 engines, but the MB-100 wasn't reliable and consumed almost of fuel per hour, weighed and developed (nominal) in 1942 and (nominal/take-off) by 1945.

References

{{Piston engine configurations Piston engine configurations