Quick answer: Helicopters achieve flight through their spinning blades, or rotors, which generate lift to move the aircraft upward. The blades are designed with a curved upper surface and flatter lower surface, causing air to flow faster over the top and reducing air pressure above the blades. This pressure difference, combined with the blades' slight angle of attack on the rotor shaft, creates lift. A helicopter with more blades can generate more lift.
If you’ve ever thought about just how heavy a helicopter is, you might have wondered how it can lift itself into the air with such ease. Without a doubt, many processes go into producing this phenomenon. So how do helicopters fly? Here are some of the basic principles that are at play in this gravity-defying machine.
Key Takeaways
- Helicopters use rotor blades spinning around a vertical axis to generate lift, allowing them to hover, move laterally, and fly in multiple directions, unlike fixed-wing aircraft.
- The tail rotor and tail rotor blades stabilize the aircraft by counteracting the torque produced by the main rotor, a solution that early helicopters lacked.
- The main rotor supplies both lift and thrust. It works alongside the advancing blade and retreating blade to balance forces and support steady directional flight.
- Blades simultaneously manage air pressure changes to maintain lift, with consistent engine power playing a crucial role in safe helicopter work.
- Cyclic and collective controls allow the pilot to fly the helicopter forward, hover, or move horizontally, using both hand and the pilot’s leg inputs.
- Military helicopters and civilian models share the same function of generating sufficient lift and adjusting motion mid-flight, with wings that create lift through constant airflow manipulation.
- When a helicopter begins to rise, more lift can be created by adjusting blade pitch. Mastery of pilot controls becomes essential in managing both altitude and directional stability.
Thrust and Lift
To move upward into the air, the helicopter must create lift, an upward force that counteracts the downward force of gravity. One principle that helps accomplish this is the difference in the air pressure above and below the rotating rotor blades of the primary rotor system on top of the helicopter. Manufacturers shape each rotor blade so that it cuts through the air as it spins. The movement results in less air pressure above, and more air pressure beneath the rotor, which helps to lift the aircraft upward.
In simpler terms, the rotor forces air below it, pushing the helicopter in the opposite direction with an upward thrust force. Professionals refer to the component of this thrust, which is in direct opposition to gravity, as lift. It is mainly this component which is at work in helicopter flight and airplane flight. However, the overall thrust of the propeller is not necessarily completely vertical to the ground. Often, it will tilt slightly in different directions to move the helicopter forward, backward, or sideways while it continues to hold itself up in the air.
Stabilization
Have you noticed that helicopters always seem to have at least two propellers located on their bodies? There is a good reason for this—Newton’s Third Law of Motion. The law states that “for every action, there is an equal and opposite reaction.” The helicopter experiences this when the force or action of the counterclockwise spinning primary rotor causes its fuselage, or main body, to spin in the clockwise direction. Without the proper reaction force, the main body would continually spin, making helicopter flying nearly impossible to control.
The purpose of the secondary rotor (or tail rotor) of a helicopter is to provide an antitorque force to counteract the torque, or turning force, created by the main rotor shaft by creating a thrust force in the opposite direction. With this, the pilot can safely maneuver the helicopter without perpetually spinning when they leave the ground.
A hovering helicopter achieves stability through its spinning blades and tail boom, ensuring balance. The rotary wing aircraft shape makes air flow seamlessly through the rotor blades. Be aware of conditions like retreating blade stall, which can affect the aircraft's performance.
These mechanisms can feel quite complex. However, with the right commercial helicopter flight school, you’ll be able to learn and apply concepts like this and many more as you learn how to pilot safely and knowledgeably. If you’re considering becoming a helicopter pilot, contact Hillsboro Heli Academy today. We can help you begin the path to a flight career and answer any questions you may have about the field.
FAQs
How does a helicopter fly, and how is it different from an airplane?
A helicopter flies by using rotor blades to generate vertical lift, unlike airplanes that rely on fixed wing aircraft. This allows rotary wing aircraft to take off and land vertically, hover, and fly in any direction, including flying forward or sideways.
What creates lift in a helicopter?
Helicopters generate lift through rotating wings called blades. As these blades move, their shape makes air flow faster over the top than underneath, reducing air pressure above and allowing them to create lift through the angle of attack and lift vector.
What keeps a helicopter stable while in the air?
The tail rotor counters the equal and opposite reaction of the main rotor, preventing the helicopter from spinning uncontrollably. This setup allows the pilot controls to adjust yaw and maintain balance using systems like the tail boom and left foot pedal.
How do helicopter controls work?
Collective and cyclic controls work together to guide the helicopter’s movement. The cyclic control changes direction, while the collective control changes lift. The swash plate assembly transfers these adjustments to the helicopter’s rotor blades to manage altitude and helicopter's direction.
Why do rotor blades spin in opposite directions?
Some main rotor blades rotate in one direction, while others move in the opposite direction to balance forces. This helps produce lift and avoid issues like retreating blade stall, which affects directional flight and stability in helicopter aerodynamics.
What’s involved in becoming a helicopter pilot?
A helicopter pilot trains to learn helicopter flight dynamics, including controlling spinning blades, managing rotor speed, and understanding lift generation. It’s very different from a fixed wing pilot’s experience due to the unique behavior of helicopter's motion and aerial screw dynamics.