What is a rigid rotor system?
Rigid Rotor System. In a rigid rotor system, the blades, hub, and mast are rigid with respect to each other. There are no vertical or horizontal hinges so the blades cannot flap or drag, but they can be feathered. Flapping and lead/lag forces are absorbed by blade bending.
What are the differences of a semi-rigid and rigid rotor system?
The semirigid rotor design is found on aircraft with two rotor blades. The blades are connected in a manner such that as one blade flaps up, the opposite blade flaps down. The rigid rotor system is a rare design but potentially offers the best properties of both the fully articulated and semirigid rotors.
What is the difference between a fully articulated rotor system and rigid rotor system?
Rigid rotor systems tend to behave like fully articulated systems through aerodynamics, but lack flapping or lead/ lag hinges. Instead, the blades accommodate these motions by bending. They cannot flap or lead/lag, but they can be feathered.
What is a rigid rotor head?
A rigid rotorhead has no flapping or lag hinges but does have pitch change bearings. The flapping and lagging movement is accommodated by flexible sections (commonly elastomeric bearings) at the blade root or blade attachment. When using composite blades, the blades can also flex to provide a flapping motion.
What is main rotor system?
A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) with a control system, that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight.
What helicopters have a rigid rotor system?
The Messerschmitt-B”lkow-Blohm BO-105 (Germany) is an example of a rigid-rotor helicopter. The rotor assembly on a fully articulated rotor system. In the semi-rigid rotor system, the blades are attached rigidly to the hub but the hub itself can tilt in any direction about the top of the mast.
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.
What is the main role of the main rotor mast?
Rotor mast — Also known as the rotor shaft, the mast connects the transmission to the rotor assembly. The mast rotates the upper swash plate and the blades. Transmission — Just as it does in a motor vehicle, a helicopter’s transmission transmits power from the engine to the main and tail rotors.
What does the pitch horn do?
The purpose of the pitch horn is to give the feathering pitch change mechanism (cyclic/swashplate) a place to attach to the blade. By sticking out from the blade, the pitch horn works as a lever, decreasing the force it takes to change the angle of the blade.
What type of rotor system does a R44 have?
The R44 is a single-engined helicopter with a semi-rigid two-bladed main rotor, a two-bladed tail rotor and a skid landing gear. It has an enclosed cabin with two rows of side-by-side seating for a pilot and three passengers.
Why do helicopter blades spin counterclockwise?
Twin rotors turn in opposite directions to counteract the torque effect on the aircraft without relying on an antitorque tail rotor. This lets the aircraft apply the power that would have driven a tail rotor to the main rotors, increasing lifting capacity.
What is a rigid rotor?
The term “rigid rotor” usually refers to a hingeless rotor system with blades flexibly attached to the hub. Irv Culver of Lockheed developed one of the first rigid rotors, which was tested and developed on a series of helicopters in the 1960s and 1970s. In a rigid rotor system, each blade flaps and drags about flexible sections of the root.
What is a helicopter rotor system?
The rotor system is the rotating part of a helicopter which generates lift. The rotor consists of a mast, hub, and rotor blades. The mast is a hollow cylindrical metal shaft which extends upwards from and is driven and sometimes supported by the transmission. At the top of the mast is the attachment point for the rotor blades called the hub.
What are the different types of rotors?
There are three basic classifications: semirigid, rigid, or fully articulated. Some modern rotor systems, such as the bearingless rotor system, use an engineered combination of these types. A semirigid rotor system is usually composed of two blades that are rigidly mounted to the main rotor hub.
What is a semirigid rotor?
A semirigid rotor system is usually composed of two blades that are rigidly mounted to the main rotor hub. The main rotor hub is free to tilt with respect to the main rotor shaft on what is known as a teetering hinge. This allows the blades to flap together as a unit.