A pulsejet engine is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically. The best known example is the Argus As 109-014 used to propel Nazi Germany's V-1 flying bomb.
The Hiller YH-32 Hornet was an American ultralight helicopter built by Hiller Aircraft in the early 1950s. It was a small and unique design because it was powered by two Hiller 8RJ2B ramjet engines mounted on the rotor blade tips which weigh 13 lb (5.9 kg) each and deliver an equivalent of 45 hp (34 kW) for a total of 90 hp (67 kW). Versions of the HJ-1 Hornet were built for the United States Army and the United States Navy in the early 1950s.
The Kaman HH-43 Huskie is a helicopter developed and produced by the American rotorcraft manufacturer Kaman Aircraft. It is perhaps most distinctive for its use of twin intermeshing rotors, having been largely designed by the German aeronautical engineer Anton Flettner.
A tip jet is a jet nozzle at the tip of some helicopter rotor blades, used to spin the rotor, much like a Catherine wheel firework. Tip jets replace the normal shaft drive and have the advantage of placing no torque on the airframe, thus not requiring the presence of a tail rotor. Some simple monocopters are composed of nothing but a single blade with a tip rocket.
The Sikorsky S-69 is an American experimental compound helicopter developed by Sikorsky Aircraft as the demonstrator of the co-axial Advancing Blade Concept (ABC) with United States Army and NASA funding.
The Bell R-12 was an American 1940s military utility helicopter built by the Bell Helicopter company. The design did not go into full production, but over a dozen prototypes were used for various tests and projects.
The Bell Model 201 was created using a modified Model 47G and was the first Bell helicopter to use a turbine engine.
The NHI H-3 Kolibrie was a small helicopter developed in the Netherlands in the 1950s by Nederlandse Helikopter Industrie. It first flew in May 1956.
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 Sud-Ouest SO.1221 Djinn is a French two-seat light helicopter designed and manufactured by aircraft manufacturer Sud-Ouest (SNCASO), which was later merged into Sud Aviation. It was the first production French helicopter, as well as being one of the first practical European helicopters to be produced. The Djinn was also the first rotorcraft to harness tip-jet propulsion to enter production, and the first production turbine powered helicopter.
The Gyrodyne RON Rotorcycle was a tiny, single-seat helicopter designed under contract for the United States Navy. in the mid-1950s. It later was redesigned for a U.S. Marine Corps requirement for a small personal helicopter that would fulfill an array of roles, including observation, liaison, small unit tactical maneuvers, and which could be dropped to downed airmen behind enemy lines to facilitate their escape.
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 Sikorsky S-52 is a utility helicopter developed by Sikorsky Aircraft in the late 1940s. It was used by the U.S. Navy, Marine Corps, and Coast Guard. The S-52 was the first US helicopter with all-metal rotor blades. Initially a two-seater, it was developed into the four-seat S-52-2 and S-52-3. It was designated HO5S-1 by the U.S. Navy and Marine Corps, HO5S-1G by the Coast Guard, and YH-18A by the U.S. Army, and was used extensively by civil operators after being retired by the military.
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 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 Doblhoff/WNF 342 was an early experimental tip jet helicopter designed and produced by Wiener-Neustädter Flugzeugwerke. It was the first helicopter to take off and land using tip jets to drive the rotor.
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 McDonnell XH-20 Little Henry was a 1940s American experimental lightweight helicopter designed and built by McDonnell Aircraft.
The Dornier Do 32E was a simple, collapsible one-man helicopter, designed for military use in Germany in the 1960s. Despite initial hopes of large orders and some proposed civilian roles, only three flew.
The McDonnell 120 Flying Crane, also V-1 Jeep, was a lightweight utility flying crane helicopter designed and built by the McDonnell Aircraft Corporation during the 1950s. The open frame fuselage supported the three gas-producers and main rotor mast, with a small single-seat cockpit in the nose, which was originally open, but later enclosed.
