FH.XI.A.K3
KnowledgeHigh and low inertia of rotor systems, as applicable.
From the FAA library
- Chapter 11: Helicopter Emergencies and Hazards › System Malfunctions › Antitorque System Failure
System Malfunctions By following the manufacturer’s recommendations regarding operating limits and procedures and periodic maintenance and inspections, many system and equipment failures can be eliminated. Certain malfunctions or failures can be traced to some error on the part ... pilot; therefore, appropriate flying techniques and use of threat and error management may help to prevent an emergency Antitorque System Failure Antitorque failure usually falls into one of two categories. One is failure of the power drive portion…
- Chapter 1: Introduction to the Helicopter › Rotor System › Tandem Rotor
Tandem Rotor Tandem rotor (sometimes referred to as dual rotor) helicopters have two large horizontal rotor assemblies, instead of one main assembly and a smaller tail rotor. [Figure 1-6] Single rotor helicopters need a tail rotor to neutralize ... twisting momentum produced by the single large rotor. Tandem rotor helicopters, however, use counter-rotating rotors, each canceling out the other’s torque. Counter-rotating rotor blades will not collide with and destroy each other if they flex into…
- Chapter 4: Helicopter Components, Sections, and Systems › Main Rotor System › Tandem Rotor
metal-to-metal contact of older bearings and the need for lubrication is eliminated in this design. Tandem Rotor Tandem rotor (sometimes referred to as dual rotor) helicopters have two large horizontal rotor assemblies; a twin rotor system, instead ... main assembly, and a smaller tail rotor. [Figure 4-10] Single rotor helicopters need an anti-torque system to neutralize the twisting momentum produced by the single large rotor. Tandem rotor helicopters, however, use counter-rotating rotors, with each canceling…
- Chapter 2: Aerodynamics of Flight › Hovering Flight › Translating Tendency (Drift)
Translating Tendency (Drift) During hovering flight, a single main rotor helicopter tends to move in the direction of tail rotor thrust. This lateral (or sideward) movement is called translating tendency. [Figure 2-27] To counteract this tendency, one or more ... following features may be used. All examples are for a counterclockwise rotating main rotor disk. Figure 2-27. A tail rotor is designed to produce thrust in a direction opposite torque. The thrust produced by the tail rotor is sufficient…
- Chapter 4: Helicopter Components, Sections, and Systems › Transmission System › Dual Tachometers
Main Rotor Transmission The primary purpose of the main rotor transmission is to reduce engine output rpm to optimum rotor rpm. This reduction is different for the various helicopters. As an example, suppose the engine rpm of a specific helicopter ... rotor speed of 450 rpm would require a 6:1 reduction. A 9:1 reduction would mean the rotor would turn at 300 rpm. Dual Tachometers Most helicopters use a dual-needle tachometer or a vertical scale instrument to show…
- Chapter 11: Helicopter Emergencies and Hazards › Low Rotor RPM and Rotor Stall
Other causes of a power-on low rotor rpm condition include the pilot rolling the throttle the wrong way in helicopters not equipped with a governor or a governor failure in helicopters so equipped. As the rpm decreases, the amount ... more difficult than it would otherwise be. With less power from the engine and less lift from the decaying rotor rpm, the helicopter will start to settle. If the pilot raises the collective to stop the settling, the situation will…