Mod 3

HELICOPTER

• uilt a two-engine coaxial helicopter that lifted a pilot untethered.
• built a tethered observation helicopter that achieved an altitude of 50 m with payload.
• uses rotating wings to provide lift, propulsion, and control.
• built a helicopter with four wing-like blades. Power was delivered to a propeller on each blade from an engine in the fuselage. Control was by aerodynamic surfaces on the blades and by a tail on the aircraft.

ROTOR BLADES

• rotate about the vertical axis, describing a disk in a horizontal or nearly horizontal plane.
• worked on sketches of a machine for vertical flight utilizing a screw-type propeller.
• uses autorotation as the normal working state of the rotor.
• developed an autogiro incorporating cyclic pitch control by means of a "spider" control mechanism to replace the direct tilt of the rotor hub.

vertical; horizontal

• Blade pitch change that is usually accomplished by movement about a hinge or bearing.
• developed a synchropter design, with two rotors in a side-by-side configuration but highly intermeshed (hub separation 0.6 m). The FL-282 had two-bladed articulated rotors (rotors 12 m in diameter, gross weight 1000 kg, 14:0 hp SiemensHalske engine).
• Rotor blades rotate about the _______ axis, describing a disk in a _______ or nearly _______ plane.
• Has three or more blades attached to the hub without hinges and the hub is attached to the rotor shaft by a universal joint arrangement.

zero

• Gyroplane No. 1 had four rotors with four biplane blades each (rotors 8 m in diameter, gross weight 580 kg, 45 hp Antoinette engine). It made a tethered flight with a passenger at an altitude of about 1 meter for about 1 minute.
• Efficient vertical flight means a __________.
• In _______, Cierva founded the Cierva Autogiro Company in England, which was his base thereafter. In the next decade about 500 of his autogiros were produced, many by licensees of the Cierva Company
• A helicopter with its rotary wings can generate aerodynamic forces even when the velocity of the vehicle itself is _______.

Translational Velocity

• received the first american certificate of airworthiness for helicopters.
• developed the Yak-24, a helicopter with two fourbladed rotors in tandem configuration. A number of dynamic problems were encountered in the development of this helicopter, but it eventually (1955) went into production.
• uses two contra-rotating rotors of equal size and loading, so that the torques of the rotors are equal and opposing.
• Rate of change of linear position.

low power loading

• demonstrated a spring-powered model to the Russian academy of sciences.
• Efficient vertical flight means a __________.
• built a small steam-driven model; he also invented the word "helicopter".
• constructed a 10-kg steam-powered model.

Power Loading (lbs/hp)

• ratio of rotor power required to rotor thrust.
• built helicopters with a side-byside configuration, in 1938
• The _______ is generally regarded as Cierva 's first successful autogiro (1926).
• developed a series of single rotor helicopters under the direction of Yuriev. The TsAGI I-EA (1931) had a four-bladed main rotor (rotor 11 m in diameter, gross weight 1100 kg, 120 hp engine) with cyclic and collective control, and two small contrarotating antitorque rotors.

Power Required

• installed power and fuel consumption of the aircraft are proportional to the _________.
• consists of two or more identical, equally spaced blades attached to a central hub.
• developed an autogiro incorporating cyclic pitch control by means of a "spider" control mechanism to replace the direct tilt of the rotor hub.
• built a helicopter with two side-by-side rotors, using a two-cylinder engine; he introduced the flapping hinge for the helicopter rotor.

low power loading

• generally considered the first practical, truly operational
• For a rotary wing, low disk loading is the key to a ______.
• The fact that the rotor is a __________ increases the first cost and maintenance cost.
• Frank N. Piasecki (Piasecki Helicopter Corporation in the United States,

disk loading

• built the VS- 300, a helicopter with a single three-bladed main rotor and a small antitorque tail rotor (rotor 9 min diameter, gross weight S20 kg, 100 hp Franklin engine). Lateral and longitudinal control was by main rotor cyclic, and directional control was by means of the tail rotor. The tail rotor was driven by a shaft from the main rotor. The pilot's controls were like the present standard (cyclic stick, pedals, and a collective stick with a twist grip throttle). Considerable experimentation was required to develop a configuration with suitable control characteristics. The first configuration had three auxiliary rotors (one vertical and two horizontal) on the tail for control and stability.
• High disk loading is appropriate for rotors operating at _________ and at a _______ equal to only a fraction of the gross weight.
• In 1942, the___________, a derivative of the VS-300, was constructed (three-bladed rotor 11.6 meters in diameter, gross weight 1100 kg, 185 hp Warner engine). This helicopter model went into production and several hundred were built during World War II.
• ratio of rotor thrust to rotor disk area