|Coastal Defense Ship||Destroyer|
|Heavy Cruiser||Training Cruiser|
|Aviation Cruiser||Fast Battleship|
|Standard Aircraft Carrier|
|Submarine||Aircraft Carrying Submarine|
|Submarine Tender||Fleet Oiler|
- Quest B132 reward.
|Improvement Cost: 200 80 120 390||★||S||M||T||W||T||F||S||Helper Ship|
|Consumes: 1x Zuiun||0||8/9||7/7||H||✗||✗||✗||✗||H||H||Hyuuga Kai Ni|
|Consumes: 1x Saiun||6||9/10||7/9|
|Consumes: 2x Type 95 Depth Charge|
1x New Model Aerial Armament Material
Produces: 1x S-51J Kai
|Ise Kai Ni||+2||+1|
|Hyuuga Kai Ni||+1||+3||+2|
Serious consideration for a rotor craft was put forth by the United States as early as 1939 as soon as the technology became available and because of Germany's successful developments in helicopters. Sikorsky and Vought jointly developed the VS-300 (also known as S-46) in September 1939. It was the first successful helicopter by the US to fly and also the first amphibious helicopter when equipped with its water floats. The VS-316 (also known as R-4) was the result of further modification of the VS-300, which was formally adopted by the US Army-Air Force, Navy and Coast Guard as the first American helicopter. By 1943, the new VS-327 was tested and flown for the first time with the intention for more serious military application. The heli's performance satisfied the US military but was still in its primitive stages to be used in serious combat. From then, many variants came out of the VS-327 as the base like the R-5 designed for search and rescue operations, which later changed into the H-5 (also known as S-48). This variant in particular was further modified to create the S-51, which had a greater carrying capacity, rotor diameter and better landing gear which was also the first commercial use helicopter.
It's true fame came after the war during the Korean War where it was used as a rescue craft, light transport, recon and utility in a very vertical and mountainous region, perfect for a helicopter. It was sold to several countries like Canada, Argentina, Australia, South Africa and the UK, who made their own extensive modifications under license as the WS-51. The British version was exported to few countries like Mexico, Norway, Congo, Belgium and Japan as civilian aircraft. This means the S-51J was militarized within the lore of the game as a fictional designation. Production ended in 1951 and was retired in 1957, paving the way for future helicopter technology.
- The VS-300 managed to beat the Fw 61 in an endurance flight by 1 hour 30 minutes.
- The Iowa-class battleships, Des Moines-class cruisers, seaplane tenders and ice breakers had their floatplanes replaced in favor of the Navy's HO3S-1, naval version of the H-5.
- It was known as the Dragonfly in the UK.
- The US Post Office jointly provided an air mail service with the USAAF to Los Angeles, California in 1946 with the H-5. Operations ended in 1971 after 2 fatal accidents.
- The S-51 also participated in Operation Highjump, becoming the first helicopter to fly in the Antarctic.
- The "R" in R-5 stood for rotor.
- AirWar article about history of Sikorsky R-5 (Russian language)
- Sikorsky H-5 (Wikipedia)
- R-5 (aircraft) (Japanese Wikipedia)
- S-51 in action
- H-5 instruction manual