Helicopter Drive System Mechanics

The video explains how a helicopter drive system transfers power from the engines to the rotors, detailing the stages of gear reduction and direction change. It covers the components of turboshaft engines, including the gas generator and power turbine, and describes the process of power transfer through various gears and couplings. The video also highlights the importance of the freewheeling unit for safety and explains the final gear reduction to achieve the desired rotor speeds. Additionally, it discusses the tail rotor drive system and its role in helicopter operation.

What is the initial speed of rotation at the engine in the helicopter drive system?

• 256 RPM

• 1,400 RPM

• 14,000 RPM

• 12,800 RPM

What is the purpose of the gas generator in a helicopter's turboshaft engine?

• To convert air and jet fuel into energy

• To extract power from hot expanding gas

• To reduce the speed of rotation

• To mechanically connect to the drive system

What is the speed of the power turbine in the model described?

• 256 RPM

• 14,000 RPM

• 12,800 RPM

• 1,400 RPM

What is the function of the flexible couplings at the front of the power turbine shafts?

• To provide a gear reduction

• To allow for minor misalignment of rotating machinery

• To disconnect a failed engine from the drive system

• To change the direction of the drive

What is the gear reduction ratio provided by the freewheeling unit?

• 2.5 to 1

• 1.875 to 1

• 5 to 1

• 2 to 1

What is the purpose of the freewheeling unit's clutch part?

• To provide a gear reduction

• To allow for minor misalignment

• To automatically disconnect a failed engine from the drive system

• To change the direction of the drive

What is the final speed of the main rotor after all gear reductions?

• 256 RPM

• 3,200 RPM

• 14,000 RPM

• 1,280 RPM

What is the purpose of the 5° forward tilt of the rotor mast?

• To change the direction of the drive

• To allow for minor misalignment

• To provide lift from the tail rotor

• To give a level fuselage attitude in forward flight

What is the gear reduction ratio of the planetary gear set?

• 1.875 to 1

• 5 to 1

• 2 to 1

• 2.5 to 1

What is the final speed of the tail rotor drive shaft?

• 1,400 RPM

• 1,280 RPM

• 3,200 RPM

• 256 RPM