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Propeller Governor
In aeronautics, a variable-pitch propeller is a type of propeller (airscrew) with blades that can be rotated around their long axis to change the blade pitch. A controllable-pitch propeller is one where the pitch is controlled manually by the pilot. Alternatively, a constant-speed propeller is one where the pilot sets the desired engine speed (RPM), and the blade pitch is controlled automatically without the pilot's intervention so that the rotational speed remains constant. The device which controls the propeller pitch and thus speed is called a propeller governor or constant speed unit. Reversible propellers are those where the pitch can be set to negative values. This creates reverse thrust for braking or going backwards without the need to change the direction of shaft revolution. Some aircraft have ground-adjustable propellers, however these are not considered variable-pitch. These are typically found only on light aircraft and microlights. Purpose When an aircraft is st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hercules
Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the Greek hero's iconography and myths for their literature and art under the name ''Hercules''. In later Western art and literature and in popular culture, ''Hercules'' is more commonly used than ''Heracles'' as the name of the hero. Hercules is a multifaceted figure with contradictory characteristics, which enabled later artists and writers to pick and choose how to represent him. This article provides an introduction to representations of Hercules in the later tradition. Mythology Birth and early life In Roman mythology, although Hercules was seen as the champion of the weak and a great protector, his personal problems started at birth. Juno sent two witches to prevent the birth, but they were tricked by one of Alcmene's servants and sent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
