What is the purpose of main rotor transmission?
What is the purpose of main rotor transmission?
The primary purpose of the main rotor transmission is to reduce engine output RPM to optimum rotor RPM. Suppose the engine speed of a specific helicopter is 2,700 RPM. Achieving a rotor speed of 450 RPM would require a 6 to 1 reduction. A 9 to 1 reduction would mean the rotor would turn at 300 RPM.
Do helicopters have a gearbox?
The main purpose of a helicopter main gearbox or transmission is to reduce output rpm of the engine to most suitable level for driving the main rotors and tail rotors of a helicopter. For example, a helicopter having an engine output rpm of 6000 but operates a rotor at 300 rpm.
What does the main rotor do on a helicopter?
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 are the 3 major components of the main rotor system?
Main Rotor System 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.
Can a helicopter fly without a 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 do helicopters have two tachometers?
Most helicopters use a dual-needle tachometer to show both engine and rotor RPM or a percentage of engine and rotor RPM. The rotor RPM needle normally is used mostly during clutch engagement to monitor rotor acceleration and in autorotation to maintain RPM within prescribed limits.
What is 90 degree gearbox in helicopter?
The tail rotor gearbox also know as the 90 degree gearbox is located at the top of the vertical fin. The purpose of the gearbox is to provide 90 degree change in direction of drive and a 2.6:1 speed (RPM) reduction between input and output drive shaft which mounts and drives the tail rotor.
What is helicopter transmission?
The transmission system transfers power from the engine to the main rotor, tail rotor, and other accessories during normal flight conditions. The main components of the transmission system are the main rotor transmission, tail rotor drive system, clutch, and freewheeling unit.
Why do helicopters have two main rotors?
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.
What are the types of a main rotor system?
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.
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 helicopter blades fall off?
A helicopter with no rotor blades. They fell off. And by “fell off,” I mean they went flying, including into a nearby truck, where, fortunately, nobody was sitting. If it’d happened a few seconds later, the result would have been tragic.