# R4

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> Source: https://en.wikipedia.org/wiki/R4
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> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

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

## Military

### Aircraft

- [Caudron R.4](/source/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](/source/Curtiss_Model_R) utility aircraft, first flown in 1915
- [Sikorsky R-4](/source/Sikorsky_R-4), American helicopter, first flown in 1942

### Ships

- [HMCS *Cayuga* (R04)](/source/HMCS_Cayuga_(R04)), Royal Canadian Navy destroyer
- [USS *R-4* (SS-81)](/source/USS_R-4_(SS-81)), U.S. Navy submarine

### Weapons

- [R4 assault rifle](/source/R4_assault_rifle), produced by South African manufacturer Vektor
- [Remington R4](/source/Remington_R4) carbine, assault rifle used by the [Philippine Marine Corps](/source/Philippine_Marine_Corps)
- [Bisnovat R-4](/source/Bisnovat_R-4), Soviet missile

### Other military

- [Plan R 4](/source/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](/source/List_of_R-phrases) "Forms very sensitive explosive metallic compounds"
- [R4 nuclear reactor](/source/R4_nuclear_reactor), the fourth nuclear reactor built in Sweden
- [Exotic R4](/source/Exotic_R4), in mathematics, a differentiable manifold

## Transportation

### Cars

- R4, abbreviation for [rear-engine, four-wheel drive layout](/source/Rear-engine,_four-wheel_drive_layout)
- [R4](/source/Group_R#R4), a sub-class of Group R rally cars
- [Jaguar R4](/source/Jaguar_R4), Jaguar Racing's car for the 2003 Formula One season
- McRae R4, a rally car designed in part by [Colin McRae](/source/Colin_McRae#Colin_McRae_R4)
- Renault R4, alternative name for the [Renault 4](/source/Renault_4)
- [Suzuki GSX-R/4](/source/Suzuki_GSX-R/4), a concept car made by Suzuki in 2001

### Roads

- R4 ring road in [Ghent](/source/Ghent), Belgium
- [R4 expressway (Czech Republic)](/source/R4_expressway_(Czech_Republic))
- [R4 expressway (Slovakia)](/source/R4_expressway_(Slovakia))
- [R-4 motorway (Spain)](/source/R-4_motorway_(Spain))
- [R4 road (Zimbabwe)](/source/R4_road_(Zimbabwe)), a road connecting Harare and Nyamapanda
- [Radial Road 4](/source/Radial_Road_4) or R-4, an arterial road of Manila, Philippines

### Other transportation

- [R4 (Canberra)](/source/R4_(Canberra)), a bus route in Canberra, Australia
- [R4 (New York City Subway car)](/source/R4_(New_York_City_Subway_car))
- [R4 (RER Vaud)](/source/R4_(RER_Vaud)), an S-Bahn line in the canton of Vaud
- [R4 (Rodalies de Catalunya)](/source/R4_(Rodalies_de_Catalunya)), a commuter rail line in Barcelona, Catalonia, Spain
- [R4 41st Avenue RapidBus](/source/R4_41st_Avenue_RapidBus), an express bus service in Vancouver, BC, Canada

## Video games

- [R4: Ridge Racer Type 4](/source/R4:_Ridge_Racer_Type_4), a racing game for Sony PlayStation, developed by Namco
- [Rush Rush Rally Racing](/source/Rush_Rush_Rally_Racing), a racing game for Sega Dreamcast, developed by Senile Team
- [R4 cartridge](/source/R4_cartridge), a Nintendo DS flash cartridge

## Other uses

- [BBC Radio 4](/source/BBC_Radio_4) the premier BBC speech radio station
- R4, a building in the [Norwegian Government quarter](/source/Regjeringskvartalet) (*Norw. Regjeringskvartalet*)
- Region 4, the [DVD region code](/source/DVD_region_code) for most of Mexico, Central America, South America, Australia, New Zealand, Oceania

## See also

- [4R (disambiguation)](/source/4R_(disambiguation))

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Adapted from the Wikipedia article [R4](https://en.wikipedia.org/wiki/R4) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/R4?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.