An intermeshing-rotor helicopter (or synchropter) is a

helicopter A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...

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 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. ...

, which saves power. However, neither rotor lifts directly vertically, which reduces efficiency per each rotor. 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 Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

Anton Flettner Anton Flettner (1 November 1885 – 29 December 1961) was a German Aerospace engineering, aviation engineer and inventor. Born in Hattersheim am Main#Eddersheim, Eddersheim (today a district of Hattersheim am Main), Flettner made important contri ...

for a small

anti-submarine warfare Anti-submarine warfare (ASW, or in the 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 ar ...

helicopter, the Flettner Fl 265 as the pioneering example, and later the Flettner Fl 282 Kolibri. During the

Cold War The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...

the American Kaman Aircraft company produced the HH-43 Huskie, for

USAF The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

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 A gas turbine or gas turbine engine is a type of Internal combustion engine#Continuous combustion, continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas gene ...

-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 a helicopter with intermeshing rotors (synchropter) designed and produced by the American manufacturer Kaman Aircraft. Developed during the 1980s and 1990s, the K-MAX builds on the work of the Ge ...

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) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Dron ...

s with intermeshing rotors have also been flown.

Examples

* Flettner Fl 265 (1939) * Flettner Fl 282 (1941) * Kellett XR-8 (1944) * Kaman K-225 (1947) * Kellett XR-10 (1947) * Praga E-1 (1947) * SNCAC NC.2001 Abeille (1949) * Kaman HH-43 Huskie (1953) * Kaman K-700 (1969) (abandoned) * Clybouw CW-105F (1973) * DeGraw RDX1091 Hummingbird (1984) *

(1991)

References

External links

* {{component-aircraft-stub Rotorcraft Helicopter components

Examples

See also

References

External links