Helicopters can hover, land on a rooftop and fly backwards, but they pay for that flexibility in speed. Even the fastest are slower than a small airliner on approach.
The short answer
Most helicopters cruise at about 100 to 160 knots, which is roughly 185 to 300 km/h (115 to 185 mph). Small training helicopters sit at the bottom of that range and large twin-engine and military types at the top.
Typical speeds by type
- Small piston trainers such as the Robinson R22: about 95 knots (175 km/h)
- Four-seat piston helicopters such as the Robinson R44: about 110 knots (205 km/h)
- Light turbine helicopters used for tours, police and news work: about 115 to 130 knots (215 to 240 km/h)
- Medium twins used for offshore and air ambulance flights: about 140 to 165 knots (260 to 305 km/h)
- Military transport such as the Black Hawk or Chinook: about 150 to 160 knots (280 to 300 km/h)
Why helicopters cannot go much faster
The limit is the main rotor. As a helicopter flies forward, the blade sweeping forward meets the air at its rotation speed plus the aircraft's speed, while the blade sweeping back meets it at its rotation speed minus the aircraft's speed.
- The advancing blade: its tip is already moving at roughly 700 km/h just from spinning. Add 300 km/h of forward speed and the tip gets close to the speed of sound, where drag and vibration rise sharply.
- The retreating blade: it meets slower and slower air as forward speed rises, until it can no longer make enough lift and stalls. This is called retreating blade stall.
Between those two effects, a conventional helicopter runs out of room somewhere around 200 knots, and most are designed to cruise well below that.
The speed record
The official record for a conventional helicopter is 400.87 km/h (249.1 mph), set by a modified Westland Lynx in 1986. Experimental compound helicopters, which add propellers or a second rotor to take load off the main rotor, have gone faster: the Eurocopter X3 reached 255 knots (about 472 km/h) in level flight in 2013.
Airspeed vs ground speed
Like any aircraft, a helicopter's quoted speeds are airspeeds. Its speed over the ground goes up with a tailwind and down with a headwind, and at helicopter speeds a 30-knot wind makes a big difference to journey time. Our piece on plane speed explains the same effect for airliners.
Can you measure it with a phone?
Usually yes, and more easily than on a plane. Helicopters fly low and have large windows, so a phone near the glass tends to hold a GPS fix well. What it shows is ground speed. Our GPS speedometer and the how fast am I going page both work in the browser, and you can switch the display to knots to match what the pilot is using. Follow the crew's instructions about phones at all times.
The takeaway
100 to 160 knots covers almost every helicopter you are likely to ride in. The rotor that lets a helicopter hover is the same thing that stops it flying much faster, which is why even record-breaking helicopters top out at around half the speed of an airliner.