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Helicopter Glossary(Limited)

This is not an all inclusive glossary. Want to see another glossary term? Please email us.


Enstrom trade show booth at Heli-Expo 2014.Advancing blade: A rotor blade that is moving in the same direction as the aircraft is called the advancing blade and the blade moving in the opposite direction is called the retreating blade. —Wikipedia

Aerodyne: A heavier-than-air aircraft (as an airplane, helicopter, or glider) —Webster

AAH: Advanced Attack Helicopter

AH: Attack Helicopter

Antitorque Rotorblade (or 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. 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 (e.i. a MD Helicopters' NOTAR, No Tail Rotor tail assembly), the helicopter would be constantly spinning in the opposite direction of the main rotor when flying. —Wikipedia

Antitorque Pedal: The pedal used to control the pitch of the tail rotor or air diffuser in a NOTAR® system. —Rotorcraft Flying Handbook, U.S. Department of Transportation. 2000, p. G-1

ARH: Attack & Reconnaissance Helicopter

Articulated: A rotor hub which provides coning/flapping and lead/lag drag hinges, as well as rotary bearings for pitch change. —Modern Fighting Helicopters, by Bill Gunston & Mike Spick, 1998, page 204.

Autorotate: Autorotation is a state of flight in which the main rotor system of a helicopter or other rotary-wing aircraft turns by the action of air moving up through the rotor, as with a gyrocopter, rather than engine power driving the rotor. The most common use of autorotation in helicopters is to safely land the aircraft in the event of an engine failure or tail-rotor failure. It is a common emergency procedure taught to helicopter pilots as part of their training. —Wikipedia

CH: Cargo Helicopter

Coaxial Rotor (or Contra-rotating co-axial rotor): A rotor system utilizing two rotors turning in opposite directions on the same centerline. This system is used to eliminate the need for a tail rotor. —Rotorcraft Flying Handbook, U.S. Department of Transportation. 2000, p. G-2

Collective Pitch Control: The control for changing the pitch of all the rotor blades in the main rotor system equally and simultaneously and, consequently, the amount of lift or thrust being generated. —Rotorcraft Flying Handbook, U.S. Department of Transportation. 2000, p. G-2

Cyclic Pitch Control: The control for changing the pitch of each rotor blade individually as it rotates through one cycle to govern the tilt of the rotor disc and, consequently, the direction and velocity of horizontal movement. —Rotorcraft Flying Handbook, U.S. Department of Transportation. 2000, p. G-2

Fully articulated rotor system: Fully articulated rotor systems use a combination of flapping and a horizontal motion that moves the retreating blades forward slightly and moves them back again on the advancing side, thus creating more relative airflow and lift on the retreating side at the expense of the advancing side. —Wikipedia

Fully rigid rotor system: A fully rigid rotor system is where the blades are rigidly fixed to the rotor hub but made of a flexible material that allows some degree of flap. —Wikipedia. The Lockheed AH-56 Cheyenne military attack prototype helicopter featured rigid main rotor blade.

Enstrom 480B on display at Heli-Expo 2014.Ground Effect: Effect of having a solid flat surface close beneath a hovering helicopter. —Modern Fighting Helicopters, by Bill Gunston & Mike Spick, 1998, page 204.

Gyroplane: “...An aircraft that gets lift from a freely turning rotary wing (rotor blades), and which derives its thrust from an engine-driven propeller.” —From the Groen Brothers website which is now offline. (Also known as: autogyros, gyros, gyrocopters, and gyroplane. One final note, gyroplanes have no tail rotor.)

HH: Search and Rescue Helicopter

HLH: Heavy Lift Helicopter

Helicopter: A rotorcraft deriving the whole or a substantial part of its lift from one or more power-driven rotors. —John Fay, The Helicopter: History, piloting and how it flies. 1989, p. 1

Helicopter, Origin of the word:
“4th September 1863, Viscount Gustave de Ponton d'On 2Amecourt used the word in a monograph entitled “La Conquete de l'air par l'helice. Expose d'un nouveau systeme d'av iation,” published in Paris. In this 40-page document he put together the Greek words helico and pteron, meaning “spiral” and “wing,”to make the word helicoptere. (Thanks Chris Jones)” —Helis website.

Helicopter, Slang Terms for: Hovering in a helicopter is the ability of the pilot to have the helicopter during flight, to stay in the same position in the air without moving forwards or backwards. Hovering in a helicopter can take low and high altitudes in the air. There are birds and insects that can hover by moving their wings quickly.

Hovering: Air-crane, angel (military: a soldier waiting to be rescued by an angel), air horse, air pony, airship, astronaut (CB Radio slang for police helicopter [Citizens Band Radio]), bear-in-the-air (CB Radio slang for police helicopter), bird, blender, Budgie (From a children's book and animated TV series in the United Kingdom), chopper, copter, eagle, eggbeater, eye in the sky (CB Radio slang for police helicopter), fly in the sky (CB Radio slang for police helicopter), flying smokey (police helicopter, certain police departments wear Smokey the Bear hats), ghetto bird (police helicopter flying over ghettos or poor neighborhoods), heli, helo, hilo, hummingbird, log bird (military: logistical resupply helicopter), rotorcopter, rotorcraft, rotory-wing, machine, sky bear (CB Radio slang for police helicopter), slick (Vietnam war: troop carrying helicopter), sky-hook, sky-crane, spy in the sky (CB Radio slang for police helicopter), whirlybird, x-ray unit. (Some of these slang terms are rather uncommon.)

Intermeshing Rotors: Counter-rotating main rotors (and no tail rotor) which allows all engine power to go directly to the main rotors for the highest lifting efficiency of any rotor configuration.

Enstrom TH180 trainer helicopter unveiled for the first time at Heli-Expo 2014.Ko Hung (320 AD): “Ko Hung describes the Chinese flying top.” ~John Fay, The Helicopter, History, Piloting and How it Flies, David and Charles, 1976, page 126.

Landing gear: Helicopters can have several types of landing gear. A common type is fixed skid landing gear as seen to the right on the orange Enstrom helicopter. A helicopter can also have fixed wheeled landing gear as well as retractable wheeled landing gear. Most wheeled landing gear is tricycle type landing gear. However, some helicopters, like the Chinook military helicopter has fixed quadricycle wheeled landing gear.

Leonardo da Vinci: Considered the father of the modern helicopter. Da Vinci was an architect, musician, anatomist, inventor, engineer, sculptor, geometer, painter, and a homosexual. He was considered the archetype of the "Renaissance man" and as a universal genius. He is also considered one of the greatest painters who ever lived. —Some excerpts quoted from Wikipedia

LOH: Light Observation Helicopter

NOTAR®: No Tail Rotor. "NO" "TA"il "R"otor. See MD Helicopters website for a complete explanation of MD Helicopters' incredible Notar® anti-torque system. This is helicopter safety and low noise at its finest.

OEM: Original Equipment Manufacturer. A manufacturer that sells a complete product to its end user. The internal parts used in the final product might be purchased from other manufacturers or internal parts might be manufactured on-site, usually a combination of both. For example: A Camaro might have Firestone tires, windows by PPG, radios by Sony, metal by US Steel but the final product is known as a General Motors Chevrolet Camaro. General Motors is the Original Equipment Manufacturer (OEM).

Optimum Speed Rotor (OSR): A rotor system designed so it's rotor speed is able to vary across a wide range and by doing so is able to find the most efficient flight condition. —Paraphrased from Defence Helicopter (magazine), Vol. 24, No. 5, October/November 2005, page 9, 1st paragraph, David S. Harvey, Editorial Director, North America.

Piston Engine: An internal combustion engine with working cylinders in which the process of combustion takes place within the cylinder or cylinders. —paraphrased from a Webster's Unabridged Dictionary of the English Language, 1989.

Retreating blade: A rotor blade that is moving in the same direction as the aircraft is called the advancing blade and the blade moving in the opposite direction is called the retreating blade. —Wikipedia

Enstrom 280FX helicopter at Heli-Expo 2013.Rotor: A system of rotating aerofoils. —John Fay, The Helicopter: History, piloting and how it flies. 1989, p. 1

Rotorblade: The rotor blades of a helicopter are long, narrow airfoils with a high aspect ratio, a shape that minimizes drag from tip vortices. Rotor blades are made out of various materials, including aluminum, composite structure, and steel or titanium, with abrasion shields along the leading edge. Rotorcraft blades are traditionally passive; however, some helicopters include active components on their blades. Tips of some helicopter blades can be specially designed to reduce turbulence and noise and to provide more efficient flying. —Wikipedia

Rotorcraft: An aerodyne which throughout all or part of its flight derives the whole or part of its lift from a rotor or rotors rotating in a substantially horizontal plane. —John Fay, The Helicopter: History, piloting and how it flies. 1989, p. 1

Rotorhead (or rotor hub): The rotorhead or rotor hub is the part of the rotorblade assembly that joins the blades to the shaft, cyclic and collective mechanisms. The rotorhead is where the lift force from the rotor blades act and allows the helicopter to fly. The rotorhead is connected to the main drive shaft via the jesus bolt and houses several other components such as the swash plate, flight control linkages and fly-bars. The rotor hub is also where the centre of gravity acts on the helicopter. —Wikipedia

Rotary-wing aircraft: A broad category of any aircraft with a moving wing, including helicopters and autogyros. This is to distinguish from fixed-wing aircraft. A third type, tilt-wing (or tilt-rotor) aircraft, are a mix of the two, as the lift surfaces in vertical flight are rotary, but stationary in forward flight. —Wikipedia

SH: Anti-Submarine Helicopter

Semi-rigid rotor system: Semi-rigid rotor systems have a horizontal hinge at the base of the blades that allow flap as they rotate. By necessity they always have an even number of blades, as each opposing pair is mechanically connected to prevent vibration. —Wikipedia

Swashplate: A disc either fixed or rotating on the main rotor drive shaft, which is tilted in various directions by the pilot's control inputs. Rods from the swashplate control the pitch angles of the blades. —Modern Fighting Helicopters, by Bill Gunston & Mike Spick, 1998, page 205.

Tail Rotor: A rotor turning in a plane perpendicular to that of the main rotor and parallel to the longitudinal axis of the fuselage. It is used to control the torque of the main rotor and to provide movement about the yaw axis of the helicopter. —Rotorcraft Flying Handbook, U.S. Department of Transportation. 2000, p. G-4

Tandem rotor system: The two main rotors are located at the front and rear extremity of a long fuselage. —Wikipedia

Enstrom 480B helicopter on display at Heli-Expo 2013.Tiltrotor: An aircraft that combines the vertical lift capability of a helicopter with the speed of a turboprop aeroplane. As the name implies, it uses tiltable (rotating) propellers, or proprotors, for lift and propulsion. For vertical flight the proprotors are angled to direct their thrust downwards, providing lift. In this mode of operation the craft is essentially identical to a helicopter. As the craft gains speed, the proprotors are slowly tilted forward, eventually becoming perpendicular to the ground. In this mode the wing provides the lift, and the wing's greater efficiency helps the tiltrotor achieve its high speed. In this mode, the craft is essentially a turboprop aircraft. —Wikipedia

Tip Path: The path in space traced out by the tips of the rotor blades. —Modern Fighting Helicopters, by Bill Gunston & Mike Spick, 1998, page 205.

Turbine Engine:An internal combustion engine in which expanding gases from the combustion chamber drive the blades of a turbine. —Webster

UH: Utility Helicopter

Variable Thrust Ducted Propeller (VTDP): A "ringtail" ducted propeller which replaces the typical tail rotor of a helicopter which results in increased speed, range, payload and reduces fuel consumption of the converted compound helicopter. The modification also includes added fixed wings. This would turn a Black Hawk helicopter into a SpeedHawk. This add-on component is being developed by Piasecki Aircraft Corp. —Paraphrased from Defence Helicopter (magazine), Vol. 25, No.1, February/March 2006, pages 33-36, by David S. Harvey, Editorial Director, North America.

VTOL: Vertical Take-Off and Landing

VSTOVL: Very Short Take-Off and Vertical Landing

VS-300: The world's first practical single main rotor helicopter built by Igor Ivanovitch Sikorsky. It first flew September 14, 1939.

About the pictures on this web page:

Helicopter Links took these pictures at Heli-Expo 2013 and Heli-Expo 2014. These pictures may not be copied or reproduced in any form such as print or electronic or any other future form of transmission without our permission. These pictures are copyrighted by Helicopter Links.

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