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

Military

Aircraft

Caudron R.4 The Caudron R.4 (officially Caudron 40 A.3) was a French World War I twin-engine biplane reconnaissance/artillery cooperation aircraft and the progenitor of a series of successful aircraft that filled a variety of roles with the French Aéronauti ...

, World War I French reconnaissance aircraft, first flown in 1915 * Curtiss R-4, air ambulance version of the American Curtiss Model R utility aircraft, first flown in 1915 * Sikorsky R-4, American helicopter, first flown in 1942

Ships

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

Weapons

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

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. H ...

, Soviet missile

Other military

* Plan R 4, the World War II British plan for an invasion of the neutral state of Norway in April 1940

Science

* R4, designation of

risk phrase {{short description, System of hazard codes and phrases for labeling dangerous chemicals and compounds Risk and Safety Statements, also known as R/S statements, R/S numbers, R/S phrases, and R/S sentences, is a system of hazard codes and phrases for ...

"Forms very sensitive explosive metallic compounds" * R4 nuclear reactor, 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, Jaguar Racing's car for the 2003 Formula One season * McRae R4, a rally car designed in part by Colin McRae * Renault R4, alternative name for the Renault 4 * Suzuki GSX-R/4, a concept car made by Suzuki in 2001

Roads

* R4 ring road in Ghent, Belgium *

R4 expressway (Czech Republic) D4 motorway ( cs, Dálnice D4), formerly Expressway R4 ( cs, Rychlostní silnice R4) is a highway in the Czech Republic, southwest from Prague. Sections of the motorway: Unfinished sections Images File: R4 near Voznice (1).jpg , Highwa ...

* R4 expressway (Slovakia) *

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

Other transportation

* R4 (Canberra), a bus route in Canberra, Australia * R4 (New York City Subway car) * R4 (Rodalies de Catalunya), a commuter rail line in Barcelona, Catalonia, Spain * R4 41st Avenue RapidBus, 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, a racing game for Sega Dreamcast, developed by Senile Team * R4 cartridge, a Nintendo DS flash cartridge

Other uses

* BBC Radio 4 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