Intermeshing-rotor helicopter

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Kaman K-Max, Missoula MT / 2010 Yakmx 2b (29167519213).jpg
Kaman K-Max, Missoula MT / 2010
HH-43 Huskie with intermeshing rotors HH-43B Huskie at Cam Ranh Bay.jpg
HH-43 Huskie with intermeshing rotors
Kaman K-MAX is optimized for external cargo load operations. Unmanned, remote control or optionally piloted variant USMC-17567.jpg
Kaman K-MAX is optimized for external cargo load operations. Unmanned, remote control or optionally piloted variant

An intermeshing-rotor helicopter (or synchropter) is a helicopter with a set of two main rotors turning in opposite directions, with each rotor mast mounted with a slight angle to the other, in a transversely symmetrical manner, so that the blades intermesh without colliding. The arrangement allows the helicopter to function without a tail rotor, which saves power. However, neither rotor lifts directly vertically, which reduces efficiency per each rotor.

Contents

Yaw is accomplished through varying torque, which is done by increasing collective pitch on one of the blade sets.

Most intermeshing designs have two blades per mast, although exceptions such as the Kellett XR-10 with three blades per mast do exist.

The arrangement was developed in Germany by Anton Flettner for a small anti-submarine warfare helicopter, the Flettner Fl 265 as the pioneering example, and later the Flettner Fl 282 Kolibri. [1] During the Cold War the American Kaman Aircraft company produced the HH-43 Huskie, for USAF firefighting purposes. One example of the Kaman K-225 experimental synchropter was fitted with a small turboshaft engine in late 1951, becoming the world's first gas turbine-powered helicopter. Intermeshing rotored helicopters have high stability and powerful lifting capability. The latest Kaman K-MAX model is a dedicated sky-crane design used for construction work, and has been modified for trials by the USMC as an optionally-unmanned cargo transporter. Unmanned aerial vehicles with intermeshing rotors have also been flown. [2]

Examples

See also

Related Research Articles

Kaman Corporation is an American aerospace company, with headquarters in Bloomfield, Connecticut. It was founded in 1945 by Charles Kaman. During the first ten years the company operated exclusively as a designer and manufacturer of several helicopters that set world records and achieved many aviation firsts.

<span class="mw-page-title-main">Tandem rotors</span> Helicopter with two horizontal rotor assemblies

A tandem-rotor helicopter is a helicopter with two large horizontal rotor assemblies mounted one in front of the other.

<span class="mw-page-title-main">Anton Flettner</span> German aviation engineer and inventor (1885–1961)

Anton Flettner was a German aviation engineer and inventor. Born in Eddersheim, Flettner made important contributions to airplane, helicopter, vessel, and automobile designs.

<span class="mw-page-title-main">Tail rotor</span>

The tail rotor is a smaller rotor mounted vertically or near-vertically at the tail of a traditional single-rotor helicopter, where it rotates to generate a propeller-like horizontal thrust in the same direction as the main rotor's rotation. The tail rotor's position and distance from the helicopter's center of mass allow it to develop enough thrust leverage to counter the reactional torque exerted on the fuselage by the spinning of the main rotor. Without the tail rotor or other anti-torque mechanisms, the helicopter would be constantly spinning in the opposite direction of the main rotor when flying.

<span class="mw-page-title-main">Kaman HH-43 Huskie</span> Helicopter with intermeshing rotors in use by the US military from the 1950s to the 1970s

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.

<span class="mw-page-title-main">Hughes XH-17</span> Type of aircraft

The Hughes XH-17 "Flying Crane" was the first helicopter project for the helicopter division of Hughes Aircraft Company. The XH-17, which had a two-bladed main rotor system with a diameter of 134 feet, still holds the world record for flying with the largest rotor system. It was capable of flying at a gross weight of more than 50,000 pounds (23,000 kg), but proved too inefficient and cumbersome to be mass-produced beyond the prototype unit.

<span class="mw-page-title-main">Flettner Fl 282</span> Type of aircraft

The Flettner Fl 282 Kolibri ("Hummingbird") is a single-seat intermeshing rotor helicopter, or synchropter, produced by Anton Flettner of Germany. According to Yves Le Bec, the Flettner Fl 282 was the world's first series production helicopter.

<span class="mw-page-title-main">Coaxial-rotor aircraft</span> Helicopter with two sets of rotor blades placed on top of each other

A coaxial-rotor aircraft is an aircraft whose rotorss are mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotating).

<span class="mw-page-title-main">Helicopter rotor</span> Aircraft component

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.

<span class="mw-page-title-main">Rotorcraft</span> Heavier-than-air aircraft which generates lift over rotating wings

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".

<span class="mw-page-title-main">Helicopter</span> Type of rotorcraft in which lift and thrust are supplied by horizontally-spinning rotors

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.

<span class="mw-page-title-main">Kaman K-MAX</span> American medium-lift helicopter

The Kaman K-MAX is a helicopter with intermeshing rotors (synchropter) designed and produced by the American manufacturer Kaman Aircraft.

<span class="mw-page-title-main">Flettner Fl 265</span> Type of aircraft

The Flettner Fl 265 was an experimental helicopter designed by Anton Flettner.

<span class="mw-page-title-main">Kellett XR-8</span> Type of aircraft

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.

<span class="mw-page-title-main">Kellett XR-10</span> Type of aircraft

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.

<span class="mw-page-title-main">Transverse-rotor aircraft</span>

A transverse-rotor aircraft is an aircraft with two large horizontal rotor assemblies mounted side by side.

<span class="mw-page-title-main">Kaman K-225</span> American experimental helicopter

The Kaman K-225 is an American experimental helicopter developed by Kaman Aircraft. One example was modified to become the world's first gas turbine-powered helicopter.

<span class="mw-page-title-main">SNCAC NC.2001 Abeille</span> Type of aircraft

The SNCAC NC.2001 Abeille was a single engine, twin intermeshing rotor helicopter designed and built in France in the late 1940s. Three were completed but only one flew, development ending when SNCAC was closed.

References

  1. Day & McNeil; Lance Day; Ian McNeil (1998). Biographical Dictionary of the History of Technology. Taylor & Francis. p. 261. ISBN   0-415-19399-0.
  2. Mortimer, Gary (13 October 2017). "Swissdrones testing heavy lift helicopter". sUASNews.com. Retrieved 16 October 2017.