The Sikorsky CH-37 Mojave is an American large heavy-lift helicopter of the 1950s.
The Sikorsky S-76 is a medium-size commercial utility helicopter designed and produced by the American helicopter manufacturer Sikorsky Aircraft. It is the company's first helicopter specifically developed for the civilian market.
The Bell 427 is a twin-engine, multirole, light utility helicopter designed and manufactured by Bell Helicopter and Samsung Aerospace Industries. It has been replaced in production by the larger Bell 429.
The Sikorsky S-67 Blackhawk was a private-venture, prototype attack helicopter built in 1970 with Sikorsky Aircraft research and development (R&D) funds. A tandem, two-seat aircraft designed around the dynamic drive and rotor systems of the Sikorsky S-61, it was designed to serve as an attack helicopter or to transport up to eight troops into combat.
The Lockheed AH-56 Cheyenne is an attack helicopter developed by Lockheed for the United States Army. It rose from the Army's Advanced Aerial Fire Support System (AAFSS) program to field the service's first dedicated attack helicopter. Lockheed designed the Cheyenne using a four-blade rigid-rotor system and configured the aircraft as a compound helicopter with low-mounted wings and a tail-mounted thrusting propeller driven by a General Electric T64 turboshaft engine. The Cheyenne was to have a high-speed dash capability to provide armed escort for the Army's transport helicopters, such as the Bell UH-1 Iroquois.
The Bell 533 was a research helicopter built by Bell Helicopter under contract with the United States Army during the 1960s, to explore the limits and conditions experienced by helicopter rotors at high airspeeds. The helicopter was a YH-40—a preproduction version of the UH-1 Iroquois—modified and tested in several helicopter and compound helicopter configurations. The Bell 533 was referred to as the High Performance Helicopter (HPH) by the Army, and reached a top speed of 274.6 knots in 1969, before being retired.
The Sikorsky S-72 was an experimental compound helicopter developed by helicopter manufacturer Sikorsky Aircraft.
The Sikorsky S-69 is an American experimental co-axial compound helicopter developed by Sikorsky Aircraft as the demonstrator of the Advancing Blade Concept (ABC) under United States Army and NASA funding.
The Bell Model 309 KingCobra was an experimental attack helicopter developed by Bell Helicopter, based on the Bell AH-1 Cobra.
The Bell R-12 was an American 1940s military utility helicopter built by the Bell Helicopter company.
The Pratt & Whitney JT12, is a small turbojet engine. The Pratt & Whitney T73 is a related turboshaft engine.
The McDonnell XV-1 is an experimental Convertiplane developed by McDonnell Aircraft for a joint research program between the United States Air Force and the United States Army to explore technologies to develop an aircraft that could take off and land like a helicopter but fly at faster airspeeds, similar to a conventional airplane. The XV-1 would reach a speed of 200 mph, faster than any previous rotorcraft, but the program was terminated due to the tip-jet noise and complexity of the technology which gave only a modest gain in performance.
The Firestone XR-9, also known by the company designation Model 45, was a 1940s American experimental helicopter built by the Firestone Aircraft Company for the United States Army Air Forces. Only two were built.
The Sikorsky XH-39, developed by Sikorsky Aircraft in 1954, was the U.S. Army's first turbine-powered helicopter. It was fast and innovative, but ultimately rejected by the United States Army in favor of the Bell UH-1 Iroquois.
The Piasecki H-16 Transporter was a tandem-rotor transport or rescue helicopter designed by Frank Piasecki and built by Piasecki Helicopter. The prototypes were evaluated by the United States Air Force and Army, but the crash of the second test aircraft led to cancelling the project.
The Lockheed CL-475 is a two-seat, single-engine light helicopter developed by Lockheed to explore rigid rotor technology. The CL-475 has a three-bladed main rotor and a two-bladed tail rotor. Only one was built.
The Bell XH-15 was an American two-seat utility helicopter designed and built by Bell Helicopter, to meet a requirement for a liaison and utility helicopter for the United States Army and United States Air Force.
The Filper ResearchModels Beta 200 and Beta 400 were small tandem, rigid rotor, helicopters intended for the personal helicopter market. Filper Research, located in San Ramon, California, was in existence from 1965 to 1968. The Beta 200 was a two place helicopter and the Beta 400 was a four place helicopter. One Beta 200 prototype and one Beta 400 prototype were manufactured and flown. Several pre-production airframes, which never flew, were also manufactured. Development testing was done in the experimental category. Development was not completed and Filper did not apply for an FAA Type Certificate for either type. There were several other variations on the basic Beta design which were contemplated but these were never developed beyond the conceptual stage. There was a fatal crash of the Beta 400 prototype in November 1967 and the company ceased operations in April 1968.
The Bell 360 Invictus was a proposed helicopter design intended to meet the United States Army requirement for a Future Attack Reconnaissance Aircraft (FARA). It is based on technology from the Bell 525 Relentless.
The Sikorsky Raider X is a compound helicopter concept with two coaxial rotors and a single pusher propeller, designed by the Sikorsky Aircraft division of Lockheed Martin for the United States Army Future Attack Reconnaissance Aircraft (FARA) program. The Raider X concept was announced in October 2019. In March 2020, the Army selected the Raider X and the Bell 360 Invictus from a field of five design concept candidates. The Raider X and 360 Invictus concepts were to be built as flying prototypes for a competition scheduled for 2023. The FARA program was cancelled in 2024.
