R4, R04, R.4, R-4, or R/4 may refer to:

Military

Aircraft

* Caudron R.4, World War I French reconnaissance aircraft, first flown in 1915 * Curtiss R-4, air ambulance version of the American

Curtiss Model R __NOTOC__ The Curtiss Model R was a utility aircraft produced for the United States Army and Navy during World War I. It was a conventional, two-bay biplane with slightly staggered wings of unequal span. The aircraft was provided with two open co ...

utility aircraft, first flown in 1915 *

Sikorsky R-4 The Sikorsky R-4 is a two-seat helicopter that was designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by ...

, American helicopter, first flown in 1942

Ships

* , Royal Canadian Navy destroyer * , U.S. Navy submarine

Weapons

R4 assault rifle The Vektor R4 is a 5.56×45mm assault rifle designed in 1979 based on the IMI Galil rifle. It entered service as the standard service rifle of the South African Defence Force (SADF) in 1980. The R4 replaced the R1, a variant of the 7.62×51mm ...

, produced by South African manufacturer Vektor * R4 carbine, assault rifle used by the

Philippine Marine Corps The Philippine Marine Corps (PMC) ( fil, Hukbong Kawal Pandagat ng Pilipinas) is the marine corps of the Philippines, a naval infantry force under the command of the Philippine Navy. The PMC conducts amphibious, expeditionary, and special ope ...

Bisnovat R-4 The Bisnovat (later Molniya) R-4 ( NATO reporting name AA-5 'Ash') was an early Soviet long-range air-to-air missile. It was used primarily as the sole weapon of the Tupolev Tu-128 interceptor, matching its RP-S ''Smerch'' ('Tornado') radar. Hi ...

, Soviet missile

Other military

Plan R 4 Plan R 4 was an unrealised British plan to invade Norway and Sweden in April 1940, during the Second World War. As a result of competing plans for Norway and a German invasion of Norway the same month, it was not carried out as designed. Simil ...

, the World War II British plan for an invasion of the neutral state of Norway in April 1940

Science

* R4, designation of risk phrase "Forms very sensitive explosive metallic compounds" *

R4 nuclear reactor History R4 nuclear reactor was a nuclear reactor built at Marviken, Vikbolandet and the fourth nuclear reactor built in Sweden. It was heavy water moderated and intended for the dual role of 130MWe of power generation as well as plutonium ...

, the fourth nuclear reactor built in Sweden * Exotic R⁴, in mathematics, a differentiable manifold

Transportation

Cars

* R4, abbreviation for

rear-engine, four-wheel drive layout In automotive design, an R4, or Rear-engine, Four-wheel-drive layout places the internal combustion engine at the rear of the vehicle, and drives all four roadwheels. This layout is typically chosen to improve the traction or the handling of e ...

* R4, a sub-class of Group R rally cars *

Jaguar R4 The Jaguar R4 is a Formula One car with which Jaguar Racing competed in the 2003 Formula One season. It was driven by Mark Webber, Antônio Pizzonia and Justin Wilson. After three years in Formula One, and amid a turbulent atmosphere that had ...

, Jaguar Racing's car for the 2003 Formula One season * McRae R4, a rally car designed in part by

Colin McRae Colin Steele McRae, (5 August 1968 – 15 September 2007) was a Scottish rally driver. He was the 1991 and 1992 British Rally Champion, and in 1995 became the first British driver and the youngest person to win the World Rally Championship ...

* Renault R4, alternative name for the

Renault 4 The Renault 4, also known as the 4L (pronounced "Quatrelle" in French), is a small economy car produced by the French automaker Renault between 1961 and 1994. Although the Renault 4 was marketed as a short station wagon, its minimal rear overhang ...

Suzuki GSX-R/4 The Suzuki GSX-R/4 is a concept car made by Suzuki is a Japanese multinational corporation headquartered in Minami-ku, Hamamatsu, Japan. Suzuki manufactures automobiles, motorcycles, all-terrain vehicles (ATVs), outboard marine engines, ...

, a concept car made by Suzuki in 2001

Roads

* R4 ring road in

Ghent Ghent ( nl, Gent ; french: Gand ; traditional English: Gaunt) is a city and a municipality in the Flemish Region of Belgium. It is the capital and largest city of the East Flanders province, and the third largest in the country, exceeded in ...

, Belgium * R4 expressway (Czech Republic) *

R4 expressway (Slovakia) R4 is an expressway ( sk, rýchlostná cesta) in the north–south direction in eastern Slovakia. It goes from border with Poland and ending at border with Hungary. It goes through or around Svidník, Prešov and Košice. The section between Pre� ...

R-4 motorway (Spain) The Autopista Radial R-4 is a Spanish radial motorway originating from Madrid and passing through Valdemoro, connecting to the N-400, Autovía A-40 and Autopista AP-36. The road is managed by Spanish Operator Cintra Cintra, S.A. (Concesione ...

Radial Road 4 Radial Road 4 (R-4), informally known as the R-4 Road, is a network of roads and bridges that all together form the fourth arterial road of Metro Manila in the Philippines. Spanning some , it connects the cities and municipalities of Makati, Manila ...

or R-4, an arterial road of Manila, Philippines

Other transportation

R4 (Canberra) Route R4 is a main cross-city bus route in Canberra, Australia operated by ACTION between Belconnen, City, Woden Town Centre and Tuggeranong.

, a bus route in Canberra, Australia *

R4 (New York City Subway car) The R4 was a New York City Subway car model built from 1932 to 1933 by the American Car and Foundry Company in Berwick, Pennsylvania. These rapid transit, subway cars were purchased for the Independent Subway System, IND Division. A total of 500 ...

R4 (Rodalies de Catalunya) The R4 is a line of Rodalies de Catalunya's Rodalies de Catalunya#Barcelona commuter rail service, Barcelona commuter rail service, operated by Renfe Operadora. It runs northwards from the northern limits of the province of Tarragona to Barcelona ...

, a commuter rail line in Barcelona, Catalonia, Spain *

R4 41st Avenue RapidBus The R4 41st Ave (designated the 91 B-Line during planning stages) is an express bus route with bus rapid transit elements in Metro Vancouver, British Columbia, Canada. Part of TransLink's RapidBus network, it replaced the 43 Express that trave ...

, an express bus service in Vancouver, BC, Canada

Video games

* R4: Ridge Racer Type 4, a racing game for Sony PlayStation, developed by Namco *

Rush Rush Rally Racing ''Rush Rush Rally Racing'', also known as ''R4'', is an independently developed, commercially released video game developed by Dutch studio Senile Team and published by RedSpotGames.

, a racing game for Sega Dreamcast, developed by Senile Team *

R4 cartridge The R4 (also known as Revolution for DS) is a flash cartridge for the Nintendo DS handheld system. It allows ROMs and homebrew to be booted on the Nintendo DS handheld system from a microSD card. This allows the user to run homebrew applicatio ...

, a Nintendo DS flash cartridge

Other uses

BBC Radio 4 BBC Radio 4 is a British national radio station owned and operated by the BBC that replaced the BBC Home Service in 1967. It broadcasts a wide variety of spoken-word programmes, including news, drama, comedy, science and history from the BBC' ...

the premier BBC speech radio station * R4, a building in the Norwegian Government quarter (''Norw. Regjeringskvartalet'') * Region 4, the

DVD region code DVD region codes are a digital rights management technique introduced in 1997. It is designed to allow rights holders to control the international distribution of a DVD release, including its content, release date, and price, all according to ...

for most of Mexico, Central America, South America, Australia, New Zealand, Oceania