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nose or tail gear is free to swivel as the helicopter is taxied on the ground. 

## POWERPLANT 

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] 

Another engine type is the gas turbine. This engine is used in most medium to heavy lift helicopters due to its 

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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. 

## FLIGHT CONTROLS 

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] 

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