Intermeshing rotors on a

helicopter 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 ...

are a set of two 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. This configuration is sometimes referred to as a synchropter. Yaw is accomplished through varying torque, which is done by increasing

collective pitch A helicopter pilot manipulates the helicopter flight controls to achieve and maintain controlled aerodynamic flight. Changes to the aircraft flight control system transmit mechanically to the rotor, producing aerodynamic effects on the rotor bla ...

on one of the blade sets. Most intermeshing designs have two blades per mast, although exceptions such as the

Kellett XR-10 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 transpo ...

with three blades per mast do exist. The arrangement was developed in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

by Anton Flettner for a small

anti-submarine warfare Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are t ...

helicopter, the

Flettner Fl 265 The Flettner Fl 265 was an experimental helicopter designed by Anton Flettner. Design and development This helicopter, developed in 1938 with the support of Nazi Germany's ''Kriegsmarine'', made it possible, for the first time, to transition from ...

as the pioneering example, and later the

Flettner Fl 282 Kolibri 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 heli ...

. During the

Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...

the American

Kaman Aircraft 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 h ...

company produced the HH-43 Huskie, for USAF firefighting purposes. One example of the

Kaman K-225 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. Design and development The K-125 was Charles Kaman's first helicopter, whi ...

experimental synchropter was fitted with a small

turboshaft engine A turboshaft engine is a form of gas turbine that is optimized to produce shaftpower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the exhaust ...

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 The Kaman K-MAX (company designation K-1200) is an American helicopter with intermeshing rotors (synchropter) by Kaman Aircraft. It is optimized for external cargo load operations, and is able to lift a payload of over , which is more than the ...

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 vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...

s with intermeshing rotors have also been flown.

List of intermeshing rotor helicopters

(1939) * Flettner Fl 282 (1941) *

Kellett XR-8 The Kellett XR-8 (later redesignated XH-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 demons ...

(1944) *

(1947) *

Praga E-1 Praga is a district of Warsaw, Poland. It is on the east bank of the river Vistula. First mentioned in 1432, until 1791 it formed a separate town with its own city charter. History The historical Praga was a small settlement located at ...

(1947) *

SNCAC NC.2001 Abeille The SNCAC NC.2001 Abeille ( en, Bee) 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. Design and developmen ...

(1949) *

Kaman HH-43 Huskie The Kaman HH-43 Huskie is a helicopter with intermeshing rotors used by the United States Air Force, the United States Navy and the United States Marine Corps from the 1950s until the 1970s. It was primarily used for aircraft firefighting and re ...

(1953) *

Kaman K-700 Kaman may refer to: * Kaman (surname) * Kamein (Kaman), an ethnic group in Burma * Kaman Aircraft, an American aerospace company and helicopter manufacturer * Kaman Music Corporation, a company of several musical instrument manufacturers * Kaman Ro ...

(1969) (abandoned) * Clybouw CW-105F (1973) * DeGraw RDX1091 Hummingbird (1984) *

(1991)

References

External links

* Rotorcraft Helicopter components {{Component-aircraft-stub

List of intermeshing rotor helicopters

See also

References

External links