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When direct control of the rotor head was perfected, the jump takeoff gyroplane was developed. Under the proper conditions, these gyroplanes have the ability to lift off vertically and transition to forward flight. Later developments have included retaining the direct con- trol rotor head and utilizing a wing to unload the rotor, which results in increased forward speed. 

## COMPONENTS 

Although gyroplanes are designed in a variety of config- urations, for the most part the basic components are the same. The minimum components required for a func- tional gyroplane are an airframe, a powerplant, a rotor system, tail surfaces, and landing gear. [Figure 15-2] An optional component is the wing, which is incorporated into some designs for specific performance objectives. 

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## AIRFRAME 

The airframe provides the structure to which all other components are attached. Airframes may be welded tube, sheet metal, composite, or simply tubes bolted together. A combination of construction methods may also be employed. The airframes with the greatest strength-to-weight ratios are a carbon fiber material or 

Direct Control—The capacity for the pilot to maneuver the aircraft by tilting the rotor disc and, on some gyroplanes, affect changes in pitch to the rotor blades. These equate to cyclic and collective con- trol, which were not available in earlier autogyros. 

Unload—To reduce the compo- nent of weight supported by the rotor system. 

the welded tube structure, which has been in use for a number of years. 

## POWERPLANT 

The powerplant provides the thrust necessary for forward flight, and is independent of the rotor system while in flight. While on the ground, the engine may be used as a source of power to prerotate the rotor system. Over the many years of gyroplane development, a wide variety of engine types have been adapted to the gyro- plane. Automotive, marine, ATV, and certificated aircraft engines have all been used in various gyroplane designs. Certificated gyroplanes are required to use FAA certificated engines. The cost of a new certificated aircraft engine is greater than the cost of nearly any other new engine. This added cost is the primary reason other types of engines are selected for use in amateur built gyroplanes. 

## ROTOR SYSTEM 

The rotor system provides lift and control for the gyro- plane. The fully articulated and semi-rigid teetering rotor systems are the most common. These are explained in-depth in Chapter 5—Main Rotor System. The teeter blade with hub tilt control is most common in homebuilt gyroplanes. This system may also employ a collective control to change the pitch of the rotor blades. With sufficient blade inertia and collective pitch change, jump takeoffs can be accomplished. 

## TAIL SURFACES 

The tail surfaces provide stability and control in the pitch and yaw axes. These tail surfaces are similar to an air- plane empennage and may be comprised of a fin and rudder, stabilizer and elevator. An aft mounted duct enclosing the propeller and rudder has also been used. Many gyroplanes do not incorporate a horizontal tail surface. 

On some gyroplanes, especially those with an enclosed cockpit, the yaw stability is marginal due to the large fuselage side area located ahead of the center of grav- ity. The additional vertical tail surface necessary to compensate for this instability is difficult to achieve as the confines of the rotor tilt and high landing pitch atti- tude limits the available area. Some gyroplane designs incorporate multiple vertical stabilizers and rudders to add additional yaw stability. 

Prerotate—Spinning a gyroplane rotor to sufficient r.p.m. prior to flight. 

