A monocopter or gyropter is a rotorcraft that uses a single rotating blade. The concept is similar to the whirling helicopter seeds that fall from some trees. The name gyropter is sometimes applied to monocopters in which the entire aircraft rotates about its center of mass as it flies. The name "monocopter" has also been applied to the personal jet pack constructed by Andreas Petzoldt. [1]
The Gyroptère was designed in 1913–1914 by Alphonse Papin and Didier Rouilly in France, inspired by a maple seed. [2] Papin and Rouilly obtained French patents 440,593 and 440,594 for their invention, and later obtained US patent 1,133,660 in 1915. [3] The Gyroptère was characterized in the contemporary French journal La Nature in 1914 as "un boomerang géant" (a giant boomerang). [4] Following demonstrations of small rocket-powered models, the Army ordered a manned prototype in 1913. [5]
Papin and Rouilly's "Gyroptère" weighed 500 kg (1,100 lb) including the float on which it was mounted. It had a single hollow blade with an area of 12 square metres (130 sq ft), counterweighted by a fan driven by an 80 hp Le Rhone rotary engine spinning at 1,200 rpm, which produced an output of just over 7 cubic metres (250 cu ft) of air per second. The fan also propelled air through the hollow blade, from which it escaped through an L-shaped tube at a speed of 100 m/s (330 ft/s). Directional control was to be achieved by means of a small auxiliary tube through which some of the air was driven and which could be directed in whatever direction the pilot wished. The pilot's position was located at the centre of gravity between the blade and the fan.
Testing was delayed due to the outbreak of World War I and did not take place until 31 March 1915 on Lake Cercey on the Côte-d'Or. Due to the difficulty of balancing the craft, a rotor speed of only 47 rpm was achieved instead of the 60 rpm which had been calculated as necessary for takeoff. In addition, the rotary engine used was not powerful enough; it had originally been planned to use a 100 hp car engine, which proved unobtainable. Unfortunately, the aircraft became unstable and the pilot had to abandon it, after which it sank. [6] [7]
The Sikorsky XV-2, also known by the Sikorsky Aircraft model number S-57, was a planned experimental stoppable rotor aircraft that was developed for a joint research program between the United States Air Force and the United States Army. The design utilized a single-rotor design: a counterweight provided stability to the rotor system, [8] while a tip-jet arrangement powered the rotor, which was to be retracted into the upper fuselage when stopped, with the XV-2 then flying like a conventional aircraft on delta wings. [9] A single jet engine was to be provided for forward flight, and was to be equipped with thrust vectoring for steering in hover and for anti-torque control in lieu of a tail rotor. [10] The program was cancelled before construction of the prototype began.
The Bölkow Bo 103 was an ultralight helicopter designed for reconnaissance and command-control purposes and constructed by Bölkow Entwicklungen KG in 1961 as part of a research order by the German Federal Ministry of Defense. It had a 6.66 m (21.9 ft) diameter monoblade rotor constructed of GRP in a single piece that incorporated its counterweight. A single prototype was built, but work was stopped in 1962 due to lack of interest on the part of the West German armed forces. [11]
The VJ-1X was an ultralight single blade helicopter powered by a rotor-mounted pulsejet. [12] Windspire, Inc. include the plans for sale in their book How to Build a Jet Helicopter. [13]
Monocopters, in which the entire aircraft rotates about its center of mass as it flies, present advantages and challenges as unmanned aerial vehicles (UAVs) to the designer. As highly centripetal machines, they cannot be manned.
The first of these monocopters were constructed by Dr. Charles W. McCutchen and powered by reciprocating model airplane engines [14] in 1952. He flew them at Lake Placid and named them "Charybdis machines". Other early experimenters were William Foshag and Joe Carter.
These types of monocopters caught on in the model airplane world, particularly in Eastern Europe, where free flight record-setting models were constructed by George Horvath of Hungary, Sergei Vorabyev [15] and V. Naidovsky of Russia, and Steffan Purice of Romania. An exception to the lack of US enthusiasm was Francis Boreham's "Buzzcopter" of 1964 [16] and Ken Willard's "Rotoriser" of 1984. [17] In 2002, Ron Jesme made the first successful electric propeller monocopter. [18] Daedalus Research of Logan Utah also manufactured a monocopter kit, "Maple Seed," using a 0.049 model-airplane engine.
Gordon Mandell of the M.I.T. Model Rocket Society designed a model-rocket engine powered monocopter, which he named "turbocopter," and published the design concept in his column "Wayward Wind" in Model Rocketry Magazine in 1969. A later version of this was researched at MIT in 1980. [19] This design prompted Korey Kline, an early member of the Tripoli Rocketry Association, to design his own rocket-powered monocopters which fly on long-burn model rocket engines. They were demonstrated at various rocket launch events in the 1980s to crowds that raved at their performance. [20] A few were manufactured as kits by Ace Rocketry at that time.
Korey Kline published very little about monocopters, rocket or otherwise, and so by the 1990s the monocopter had faded from view. Edward Miller of Pennsylvania began experimenting with them again in the late 1990s, as well as Francis Graham, a Kent State University, Ohio, physics professor. By 1999 both were flying rocket monocopters. Francis Graham wrote a book, Monocopters, [21] with some theory of their flight characteristics, in 1999, sold by Apogee Components of Colorado Springs. Ed Miller went on to build the largest high power rocket monocopters ever flown, [22] [23] with 8 foot large fiberglass-covered wooden wings, and also sells them. Chuck Rudy flew a large monocopter with a hybrid rocket engine, using solid and liquid fuel. [24] Francis Graham continued to promote monocopters and organized a small conference held in Washington, Pennsylvania, in 2001. He also presented a paper on the subject at the 2003 Century-of-Flight conference sponsored by the AIAA in Dayton. [25]
Joseph Peklicz of Martin's Ferry scaled down the monocopter into a kit form using small model rocket engines [26] [27] and sold many to individuals and schools. His kits are still available and widely sold. In 2008, Art Applewhite of Kerrville, Texas, began selling a popular line of rocket-powered monocopter kits as well.
Monocopters that rotate entirely had no practical purpose prior to 2003, but, due in part to Graham's book, that would change. Patent 7,104,862 [28] was awarded in 2006 to Michael A. Dammar of Vera-Tech Aero RPV Corp. of Edina, Minnesota, for a monocopter military reconnaissance device that was remotely controlled and took short exposures. Another remote-controlled monocopter, which could fly indoors on an electric motor, and which uses the Earth's magnetic field as a reference, was developed by Woody Hoburg and James Houghton at MIT in 2007–2008.
The Fairey Rotodyne was a 1950s British compound gyroplane designed and built by Fairey Aviation and intended for commercial and military uses. A development of the earlier Fairey Jet Gyrodyne, which had established a world helicopter speed record, the Rotodyne featured a tip-jet-powered rotor that burned a mixture of fuel and compressed air bled from two wing-mounted Napier Eland turboprops. The rotor was driven for vertical takeoffs, landings and hovering, as well as low-speed translational flight, but autorotated during cruise flight with all engine power applied to two propellers.
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 Piasecki X-49 "SpeedHawk" is an American four-bladed, twin-engined experimental high-speed compound helicopter developed by Piasecki Aircraft. The X-49A is based on the airframe of a Sikorsky YSH-60F Seahawk, but utilizes Piasecki's proprietary vectored thrust ducted propeller (VTDP) design and includes the addition of lifting wings. The concept of the experimental program was to apply the VTDP technology to a production military helicopter to determine any benefit gained through increases in performance or useful load.
On a helicopter, the main rotor or rotor system is the combination of several rotary wings with a control system, that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight. Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which connects through a combination of drive shaft(s) and gearboxes along the tail boom. The blade pitch is typically controlled by the pilot using the helicopter flight controls. Helicopters are one example of rotary-wing aircraft (rotorcraft). The name is derived from the Greek words helix, helik-, meaning spiral; and pteron meaning wing.
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.
A Fenestron is an enclosed helicopter tail rotor that operates like a ducted fan. The term Fenestron is a trademark of multinational helicopter manufacturing consortium Airbus Helicopters. The word itself comes from the Occitan term for a small window, and is ultimately derived from the Latin word fenestra for window.
A gyrodyne is a type of VTOL aircraft with a helicopter rotor-like system that is driven by its engine for takeoff and landing only, and includes one or more conventional propeller or jet engines to provide forward thrust during cruising flight. During forward flight the rotor is unpowered and free-spinning, like an autogyro, and lift is provided by a combination of the rotor and conventional wings. The gyrodyne is one of a number of similar concepts which attempt to combine helicopter-like low-speed performance with conventional fixed-wing high-speeds, including tiltrotors and tiltwings.
A rotorcraft or rotary-wing aircraft is a heavier-than-air aircraft with rotary wings or rotor blades, which generate lift by rotating around a vertical mast. Several rotor blades mounted on a single mast are referred to as a rotor. The International Civil Aviation Organization (ICAO) defines a rotorcraft as "supported in flight by the reactions of the air on one or more rotors".
A convertiplane is defined by the Fédération Aéronautique Internationale as an aircraft which uses rotor power for vertical takeoff and landing (VTOL) and converts to fixed-wing lift in normal flight. In the US it is further classified as a sub-type of powered lift. In popular usage it sometimes includes any aircraft that converts in flight to change its method of obtaining lift.
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.
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of short take-off and landing (STOL) or short take-off and vertical landing (STOVL) aircraft cannot perform without a runway.
The Sikorsky X2 is an experimental high-speed compound helicopter with coaxial rotors, developed by Sikorsky Aircraft, that made its first flight in 2008 and was officially retired in 2011.
The Bölkow Bo 46 was a West German experimental helicopter built to test the Derschmidt rotor system that aimed to allow much higher speeds than traditional helicopter designs. Wind tunnel testing showed promise, but the Bo 46 demonstrated a number of problems and added complexity that led to the concept being abandoned. The Bo 46 was one of a number of new designs exploring high-speed helicopter flight that were built in the early 1960s.
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 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 slowed rotor principle is used in the design of some helicopters. On a conventional helicopter the rotational speed of the rotor is constant; reducing it at lower flight speeds can reduce fuel consumption and enable the aircraft to fly more economically. In the compound helicopter and related aircraft configurations such as the gyrodyne and winged autogyro, reducing the rotational speed of the rotor and offloading part of its lift to a fixed wing reduces drag, enabling the aircraft to fly faster.
The Sikorsky XV-2, also known by the Sikorsky Aircraft model number S-57, was a planned experimental stoppable rotor aircraft, designated as a convertiplane, developed for a joint research program between the United States Air Force and the United States Army. The program was canceled before construction of the prototype began.
The Sikorsky S-97 Raider is a high-speed scout and attack compound helicopter based on the Advancing Blade Concept (ABC) with a coaxial rotor system under development by Sikorsky Aircraft. Sikorsky planned to offer it for the United States Army's Armed Aerial Scout program, along with other possible uses. The S-97 made its maiden flight on 22 May 2015.