The Kamov Ka-26 is a Soviet light utility helicopter with co-axial rotors.
The Kamov Ka-15 was a Soviet two-seat utility helicopter with coaxial rotors, which first flew on 14 April 1952 at the hands of test pilot D. K. Yefremov. It was the world's first mass-produced coaxial helicopter. State acceptance trials were completed in 1955, and the helicopter entered production the following year at aircraft factory No. 99 in Ulan-Ude. It was a precursor to the Ka-18 and was fitted with the M-14 engine. It was primarily used for bush patrol, agricultural purposes and fishery control.
The PZL Kania is a follow-up design to the Mil Mi-2 helicopter, developed in Poland by PZL-Świdnik.
The Ling-Temco-Vought (LTV) XC-142 was a tri-service tiltwing experimental aircraft designed to investigate the operational suitability of vertical/short takeoff and landing (V/STOL) transports. An XC-142A first flew conventionally on 29 September 1964, and on 11 January 1965, it completed its first transitional flight by taking off vertically, changing to forward flight and finally landing vertically. Its service sponsors pulled out of the program one by one, and it eventually ended due to a lack of interest after demonstrating its capabilities successfully.
The Agusta A.104 Helicar was an Italian prototype light commercial helicopter first flown in December 1960.
The Agusta AB.102 was an Italian helicopter produced in small numbers in the early 1960s. The aircraft was based on the mechanical components of a Bell 48 that Agusta incorporated into an all-new, streamlined fuselage. The first flight was on 3 February 1959 and the prototype was exhibited at that year's Paris Air Show in faux military colours. Only two production examples were built, operated by Elivie in a regular air service between Turin and Milan from 1961. However, the advent of turbine-powered helicopters in the 1960s soon rendered the AB.102 obsolete.
The Bölkow Bo 103 was an ultralight experimental helicopter flown in West Germany in 1961. It was designed for reconnaissance and command-control purposes and constructed by Bölkow Entwicklungen KG as part of a research order by the German Federal Ministry of Defense.
The Doman LZ-5 was a utility helicopter developed in the United States in the early 1950s by Doman Helicopters Inc. of Danbury, Connecticut. Despite the procurement of international manufacturing agreements, no series production of the aircraft ever occurred, and only three prototypes were built. Two of these were purchased by the United States Army as the YH-31, but eventually becoming VH-31.
The Kamov Ka-126 is a Soviet light utility helicopter with co-axial rotors. Evolved from Ka-26 with engine pods removed from stub wings, fitted with one TVO-100 turboshaft engine positioned on top of fuselage, modified rotor blades, new fuel system.
The Kamov Ka-118 is a projected light multirole helicopter with the NOTAR configuration based on the McDonnell Douglas design.
The DF Helicopters DF334 is a two-seat, single-engine light utility helicopter in development by Dragon Fly Helicopters in Northern Italy. The DF 334 is a development of the Dragon Fly 333, developed by archaeologists and filmmakers Angelo and Alfredo Castiglioni in the 1980s. The DF334 has a larger, full composite cabin, a Rotax 914 4-stroke turbocharged engine, a governor fuel control, and an advanced Electronic Flight Instrument System. The helicopter is intended for both amateur and professional pilots.
The Kawasaki KH-4 was a light utility helicopter produced in Japan in the 1960s as a development of the Bell 47 that Kawasaki had been building under licence since 1952. The most visible difference between the KH-4 and its forerunner was its new and enlarged cabin. This was fully enclosed and provided seating for three passengers side-by-side on a bench seat behind the pilot's seat. The helicopter was provided with a new control system, revised instrumentation, and larger fuel tank.
The Kellett XR-8 was a helicopter built in the United States during World War II. It was a two-seat machine intended to demonstrate the feasibility of a twin-rotor system, and while it accomplished this, it also demonstrated a number of problems that prevented further development of this particular design.
The Kellett XR-10 was a military transport helicopter developed in the United States in the 1940s that only flew in prototype form. It was designed in response to a USAAF Technical Instruction issued for the development of a helicopter to transport passengers, cargo, or wounded personnel within an enclosed fuselage. Kellett's proposal followed the general layout that the company was developing in the XR-8, with twin intermeshing rotors, and was accepted by the Air Force on 16 October over proposals by Sikorsky, Bell, and Platt-LePage.
The Super Rotor AC.4 Andorinha ("Swallow") was a sport autogyro first produced in Brazil in the 1960s. The prototype was built by Altair Coelho and flown in 1960 as the AC.1, a typically minimalist autogyro design consisting of an open framework supporting the pilot's seat, rotor mast, engine mounting and tail fin. Power was supplied by a converted Volkswagen engine driving a pusher propeller. Francisco Mattis purchased the prototype and manufacturing rights and founded Super Rotor of São Paulo to produce the aircraft. Refinements for serial production as the AC.4 included an extra reinforcing strut for the rotor mast and a larger tail fin.
The Nord 1750 Norelfe was a 1950s French three-seat helicopter built by Nord Aviation and designed by Jean Cantinieau.
The Airmaster H2-B1 is a British two-seat ultralight helicopter built by Airmaster Helicopters of Camberley, Surrey.
The PZL SM-4 Łątka was a prototype three-seat helicopter of the 1960s, developed by WSK PZL-Świdnik in Poland. Of largely conventional design and construction, a single prototype was built, but was not flown as a result of engine problems.
The Matra-Cantinieau MC-101 was an early 1950s French experimental two seat helicopter of conventional tail rotor configuration but with its engine mounted close to the main rotor, above the seating.
The Hoppi-Copter was a functional backpack helicopter developed by Hoppi-Copters Inc. founded by Horace T. Pentecost in the 1940s. The original Hoppi-Copter consisted of two contra-rotating rotors on a pole attached to a motorized backpack. Although it was capable of flight, it was extremely hard to control.
