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Every Mechanism

Home How a Helicopter Works

Lift, power and control

How a helicopter works

It climbs straight up, hovers and flies any way it likes. Here is everything that makes it happen.

Try the controls
A red and white rescue helicopter hovering low over larch and pine trees at golden hour, its rotor a blur, a granite cliff behind.
A light rescue helicopter, modelled on the Airbus H125, hovering by the cliffs.
390rpm
main rotor, held steady
786km/h
blade tips, in a hover
15.4: 1
main gearbox
2,250kg
maximum weight

Video

How a Helicopter Works - Engine, Rotor and Controls Explained

Watch on YouTube

3D model · see-through · 360°

Start it, fly it, take it apart

Start the engine, then fly with the three controls below. Drag to turn, scroll to zoom, click any part.

Try itPress Start engine, then raise the collective.
Loading the 3D model…
fwdbackLR
Cyclic
Spin

Meet the parts

Seventeen parts under the skin

The helicopter with its skin and cabin taken away. Tap a part or pick a name.

The helicopter with its skin and cabin removed, standing on its skids: the three long blades and the rotor head on top, the swashplate and servos, the main gearbox on its slanted bars, the engine behind it, the long tail drive shaft to the tail rotor, the orange fuel tank below, and the pilot’s controls in front.

Hover or tap the picture. Red rings mark every part.

Parts diagram

From the fuel tank to the rotor

Seen from the left, the skin see-through and the engine and gearboxes cut open. The numbers follow the power.

The helicopter from its left side with see-through skin: the fuel tank under the cabin, the engine behind the gearbox cut open to show its compressor, combustion chamber and turbines, the freewheel and the main gearbox with its bevel and planet gears, the mast, swashplate, servos and rotor head, the long tail drive shaft, the tail gearbox and tail rotor, and the cyclic and collective in the cockpit. Twenty numbered parts.
    How it works, step by step

    The video’s 44 steps

    Eight chapters, from lift to landing. Show me in 3D sets the model up for each one.

        Lifting off from the pad.
        Step 1 of 44

        Up, hover, any way

          Try it yourself

          Four things to try

          Demo 1 · blade pitch and lift

          Make enough lift

          More pitch, more lift, until the blade stalls. Match the weight to hover.

          –lift
          –weight
          –vertical speed
          –the air on the blade

          Demo 2 · the cyclic and phase lag

          Tilt the rotor

          Drag the stick. Each blade gets most pitch a quarter turn before it rises highest.

          –stick
          –most pitch
          –blade rises highest
          –the disc tilts

          Demo 3 · torque and the tail rotor

          Stop the spin

          The rotor twists the body the other way. Balance it with the pedals.

          –rotor torque
          –tail rotor push
          –push × 6.1 m lever
          –the nose

          Demo 4 · if the engine stops

          Land without power

          Cut the engine, lower the collective at once, flare near the ground, then cushion the landing.

          –rotor
          –height
          –descent
          –airspeed

          More to know

          Kinds, history and safety

          Six ways to beat the torque

          This oneMain and tail rotorA small side rotor stops the spin.
          Heavy liftersTandemTwo big rotors, front and back, turning opposite ways.
          CompactCoaxialTwo rotors on one mast, turning opposite ways.
          Quieter, safer tailFenestronA many-bladed fan inside the tail fin.
          No tail rotorNOTARAir blown out of the tail boom.
          DronesMulticopterFixed propellers; it steers by changing their speeds.

          From a sketch to Everest

          1. Leonardo da Vinci sketches an “aerial screw”.
          2. Paul Cornu’s twin-rotor machine lifts him off for a few seconds.
          3. The Focke-Wulf Fw 61, the first practical helicopter, flies.
          4. Sikorsky’s VS-300: one main rotor and a tail rotor.
          5. The Alouette II flies, powered by a turboshaft engine.
          6. First flight of the Écureuil, this helicopter’s family.
          7. One of the family lands on the summit of Everest.

          Around a helicopter

          • Approach from the front, where the pilot can see you, and only when signalled.
          • Keep clear of the tail rotor. Spinning, it is almost invisible.
          • Crouch and hold on to hats and bags under the rotor.
          • On a slope, come from below: the blades pass lower uphill.

          Things worth knowing

          Tips at 786 km/hAt 390 rpm, in a hover.
          Steady rotor speedThe pilot changes the pitch, not the speed.
          It hangs from the gearboxFour slanted bars carry the whole body.
          Two turbines, no linkOnly the hot gas turns the free turbine.
          A magnet in the oilIt catches metal chips and warns the pilot.
          Engine out, still safePilots practise autorotation landings.
          Quick check

          Four questions