Some helicopters incorporate a stability augmentation system (SAS) to help stabilize the helicopter in flight and in a hover. The original purpose and design allowed decreased pilot work load and lessened fatigue. It allowed pilots to place an aircraft at a set attitude to accomplish other tasks or simply stabilize the aircraft for long cross-country … Read more
Most helicopters, other than smaller piston-powered helicopters, incorporate the use of hydraulic actuators to overcome high control forces. A typical hydraulic system consists of actuators, also called servos, on each flight control, a pump which is usually driven by the main rotor transmission and a reservoir to store the hydraulic fluid. Some helicopters have accumulators … Read more
The electrical systems, in most helicopters, reflect the increased use of sophisticated avionics and other electrical accessories. [Figure] More and more operations in today’s flight environment are dependent on the aircraft’s electrical system; however, all helicopters can be safely flown without any electrical power in the event of an electrical malfunction or emergency. Helicopters have … Read more
The fuel system in a helicopter is made up of two groups of components: the fuel supply system and the engine fuel control system. Fuel Supply System The supply system consists of a fuel tank or tanks, fuel quantity gauges, a shut-off valve, fuel filter, a fuel line to the engine, and possibly a primer … Read more
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 … Read more
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. The freewheeling unit or autorotative clutch allows the main rotor transmission to drive the … Read more
Reciprocating Engines Reciprocating engines, also called piston engines, are generally used in smaller helicopters. Most training helicopters use reciprocating engines because they are relatively simple and inexpensive to operate. Turbine Engines Turbine engines are more powerful and are used in a wide variety of helicopters. They produce a tremendous amount of power for their size … Read more
Title 14 of the Code of Federal Regulations (14 CFR) part 91 requires pilot compliance with the operating limitations specified in approved rotorcraft flight manuals, markings, and placards. Originally, flight manuals were often characterized by a lack of essential information and followed whatever format and content the manufacturer deemed appropriate. This changed with the acceptance … Read more
Antitorque System Helicopters with a single, main rotor system require a separate antitorque system. This is most often accomplished through a variable pitch, antitorque rotor or tail rotor. [Figure 1] Figure 1. Antitorque rotor produces thrust to oppose torque Pilots vary the thrust of the antitorque system to maintain directional control whenever the main rotor … Read more
Swash Plate Assembly The purpose of the swash plate is to convert stationary control inputs from the pilot into rotating inputs which can be connected to the rotor blades or control surfaces. It consists of two main parts: stationary swash plate and rotating swash plate. [Figure 1] The stationary swash plate is mounted around the … Read more