How does a tandem rotor helicopter work?
Tandem rotor (or dual rotor)
A tandem rotor helicopter has two main rotor systems and no tail rotor. Usually the rear rotor is mounted at a higher position than the front rotor, and the two are designed to avoid the blades colliding, should they flex into the other rotor’s pathway.
What type of rotor is found on aircraft with dual rotor blades?
Tandem rotor (sometimes referred to as dual rotor) helicopters have two large horizontal rotor assemblies; a twin rotor system, instead of one main assembly, and a smaller tail rotor.
What are the 3 types of helicopter tail rotor?
There are three basic classifications: rigid, semirigid, and fully articulated, although some modern rotor systems use a combination of these classifications. A rotor is a finely tuned rotating mass, and different subtle adjustments reduce vibrations at different airspeeds.
How does a tandem rotor helicopter compensate for torque effect?
In tandem rotor and coaxial helicopter designs, the rotors turn in opposite directions to neutralize or eliminate torque effects. In tip-jet helicopters, power originates at the blade tip and equal and opposite reaction is against the air; there is no torque between the rotor and the fuselage.
How are the aerodynamic forces of the rotor controlled?
Explanation: The aerodynamic forces of the rotor is controlled using the pitch motion which helps in altering the angle of attack of the rotor blade. The change of blade pitch angle is known as feathering motion.
How does a tandem helicopter yaw?
Tandem rotor designs achieve yaw by applying opposite left and right cyclic to each rotor, effectively pulling both ends of the helicopter in opposite directions.
What is a tandem-rotor helicopter called?
The twin-engine, tandem-rotor CH-47 Chinook helicopter is one of the world’s most iconic and recognizable military aircraft.
Can helicopters fly without tail rotor?
Without the tail rotor or other anti-torque mechanisms (e.g. NOTAR), the helicopter would be constantly spinning in the opposite direction of the main rotor when flying.
Why is a tail rotor not required on a tandem rotor helicopter?
A tandem rotor helicopter has two main rotors; one at the front of the fuselage and one at the back (Figure 2b). This type of configuration does not need a tail rotor because the main rotors are counter rotating.
How do helicopters stay balanced?
A helicopter remains stationary by balancing the external forces. There are no horizontal forces, as the helicopter is not moving left or right, so there is no drag or horizontal thrust. The blades generate a vertical lift, and when this is exactly balanced with the force of gravity, the helicopter remains stationary.
What are the four forces acting on a helicopter?
There are four forces acting on a helicopter in flight. They are lift, weight, thrust, and drag. See figure 2-1. Lift is the upward force created by the effect of airflow as it passes around an airfoil.
How do Chinook blades not hit each other?
The two rotors are linked by a transmission that ensures the rotors are synchronized and do not hit each other, even during an engine failure. Tandem rotor designs achieve yaw by applying opposite left and right cyclic to each rotor, effectively pulling both ends of the helicopter in opposite directions.
Why do Russian military helicopters have two rotors?
Having two coaxial sets of rotors provides symmetry of forces around the central axis for lifting the vehicle and laterally when flying in any direction. Because of the mechanical complexity, many helicopter designs use alternate configurations to avoid problems that arise when only one main rotor is used.
Can a Chinook fly on one rotor?
Tandem-rotor helicopters, such as the Boeing CH-46 Sea Knight and CH-47 Chinook, are helicopters with rotors distant by more than 10 m. It seems unlikely a single rotor could sustain the force moment created by the failure of the other rotor.
Can a helicopter survive tail rotor failure?
It is perfectly possible to recover from a tail rotor failure. There are some flight regimes that might lead to a crash with all but the best pilot and some luck. A tail rotor failure in cruise should be survivable, especially if you can find something hard to land on.
Can a helicopter land without a tail 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.
Where should the center of gravity be on a helicopter?
There is no fixed rule for its location, and it may be located forward of the nose of the aircraft. For helicopters, it may be located at the rotor mast, the nose of the helicopter, or even at a point in space ahead of the helicopter.
Why do helicopters stay in one spot?
There are no horizontal forces, as the helicopter is not moving left or right, so there is no drag or horizontal thrust. The blades generate a vertical lift, and when this is exactly balanced with the force of gravity, the helicopter remains stationary. This is due to Newton’s Second Law.
What are the 4 forces of aerodynamics?
These same four forces help an airplane fly. The four forces are lift, thrust, drag, and weight. As a Frisbee flies through the air, lift holds it up. You gave the Frisbee thrust with your arm.
What forces must equal for a helicopter to hover?
The sum of the lift and thrust forces must equal the sum of the weight and drag forces in order for the helicopter to hover. During vertical flight in a no-wind condition, the lift and thrust forces both act vertically upward. Weight and drag both act vertically downward.
Do Chinook blades spin the same direction?
The size is not the only thing that sets the Chinook apart. The aft rotor blades, unlike forward blades, have a clockwise spin while all other blades rotate counter-clockwise. “There’s no other blade like it,” notes Roy Hollins, the director of Components Production at CCAD.
Is the KA 52 better than the Apache?
So you can give an armament edge to the Ka-52, and it is slightly faster at 186 mph instead of 173. But the Apache can fly 1,180 miles in straight and level flight against a mere 683 for the Ka-52. And it can fly higher, reaching 21,000 feet while the Ka-52 runs out of air at just over 18,000 feet.
Why does the KA 50 have 2 rotors?
Two is Better than One
Rather than a main blade rotor and a tail rotor assembly, the KA-50 forgoes the tail rotor for another main rotor. These two main rotors spin in opposite directions and give the KA-50 a very high degree of maneuverability and performance when compared to typical tail-rotor helicopters.
Why do Russian helicopters have 2 rotors?
Can you start a helicopter in free fall?
RE: Starting Helicopter In Free Fall
It wouldn’t. There would be no reason for it. In rotary wing flight, autorotation would never happen if the rotor wasn’t already at operating RPM at the moment of engine failure.