Helicopter blades act in the same way as the wings of an airplane. They generate lift with the air flowing faster on the top of the airfoil then on the bottom. When you reach a certain speed, depending on blade specifications and limits, the air flowing over the blades become equal on the top and bottom of the airfoil. This is what is known as blade stall. The blades no longer generate lift. The same effect in fixed wing aircraft is known as a speed stall. This concept also takes place when a helicopter flies too high. As the air thins with altitude eventually there is not enough air for the blade to "bite". Thus blade stall again.
Most helicopters fly at about 170 knots, but some are faster.
Their maximum speed is listed as 315 km/h.
Retreating blade stall.
The BMW E46 has a maximum speed of 155 mph when electronic limitations are placed on it and 192 mph when there are no limits. These are the European specifications.
A CH-47's max allowable airspeed will vary with gross weight, altitude and air density, but the limitations chapter in the operator's manual specifies 170 knots (196 mph) as absolute maximum airspeed.
The BMW Type 501 1957 has a maximum speed of 155 miles per hour. If there are any electronic limitations placed on the car, the maximum speed is more like 192 miles per hour.
Not all army helicopters have the same weight. The Sikorsky UH-60 Blackhawk helicopter weighs 13,648 pounds when empty. This helicopter has a maximum speed of 173 miles per hour.
The fastest car is faster than the fastest police helicopter. However, cars are generally limited to roads and traversible ground, whereas a helicopter can fly a straight line from point A to point B. There are several instances of criminals with fast cars who have managed to lose police helicopters in pursuit. However, they pale into insignificance against the criminals in fast cars who don't. The physics of any rotary wing propulsion device restricts it's forward speed to around 250 mph. The fastest helicopter in the world currently is the Westland Lynx with a maximum forward speed of 249.10 mph.
limitations of speed of the rotors (wings) where the density of the air demands a faster movement to create lift.
The "advancing blade" of a helicopter refers to the side of the rotor which moves forward in relation to the fuselage. As each rotor blade makes a full circle around the center, on one side of the swing, it moves forward, and on the opposite side it is moving towards the rear of the helicopter. When the helicopter is moving forward in air, the rotor blades on the advancing side are moving at a higher airspeed than the rotor blades elsewhere. Rotor speed + aircrafts forward airspeed. This results in slightly more lift on that side. Conversely the exact opposite is happening on the other side where you get Rotor speed - aircraft forward airspeed. This creates a tendency for helicopters to want to roll at high airspeed. This is one of the many odd tendencies of rotor aircraft that pilots are constantly adjusting to balance out.
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At 2pm EDT Earl's forward speed was 15mph, while his maximum sustained winds were 125 mph.