large horsepower output. The engine drives the main transmission, which then transfers power directly to the main rotor system, as well as the tail rotor. nose or tail gear is free to swivel as the helicopter is taxied on the ground. A typical small helicopter has a reciprocating engine, which is mounted on the airframe. The engine can be mounted horizontally or vertically with the transmis- sion supplying the power to the vertical main rotor shaft. [Figure 1-6] When you begin flying a helicopter, you will use four basic flight controls. They are the cyclic pitch control; the collective pitch control; the throttle, which is usually a twist grip control located on the end of the collective lever; and the antitorque pedals. The col- lective and cyclic controls the pitch of the main rotor blades. The function of these controls will be explained in detail in Chapter 4—Flight Controls. [Figure 1-7] Another engine type is the gas turbine. This engine is used in most medium to heavy lift helicopters due to its Figure 1-7. Location of flight controls. Figure 1-5. While in a hover, Coanda Effect supplies approxi- mately two-thirds of the lift necessary to maintain directional control. The rest is created by directing the thrust from the controllable rotating nozzle. Figure 1-6. Typically, the engine drives the main rotor through a transmission and belt drive or centrifugal clutch system. The antitorque rotor is driven from the transmission. Main RotorGLYPH<.notdef> Wake RotatingGLYPH<.notdef> Nozzle Downwash AirGLYPH<.notdef> Jet Lift Air Intake MainGLYPH<.notdef> Rotor MainGLYPH<.notdef> Transmission AntitorqueGLYPH<.notdef> Rotor Engine Cyclic Throttle Collective AntitorqueGLYPH<.notdef> Pedals 1-3 FLIGHT CONTROLS POWERPLANT