An extract on #thegreatoutdoors
All "fly-by-wire" flight control systems eliminate the complexity, the fragility, and the weight of the mechanical circuit of the hydromechanical or electromechanical flight control systemseach being replaced with electronic circuits. The control mechanisms in the cockpit now operate signal transducers, which in turn generate the appropriate electronic commands. These are next processed by an electronic controllereither an analog one, or (more modernly) a digital one. Aircraft and spacecraft autopilots are now part of the electronic controller.
The hydraulic circuits are similar except that mechanical servo valves are replaced with electrically controlled servo valves, operated by the electronic controller. This is the simplest and earliest configuration of an analog fly-by-wire flight control system. In this configuration, the flight control systems must simulate "feel". The electronic controller controls electrical feel devices that provide the appropriate "feel" forces on the manual controls. This was used in Concorde, the first production fly-by-wire airliner.
In more sophisticated versions, analog computers replaced the electronic controller. The canceled 1950s Canadian supersonic interceptor, the Avro Canada CF-105 Arrow, employed this type of system. Analog computers also allowed some customization of flight control characteristics, including relaxed stability. This was exploited by the early versions of F-16, giving it impressive maneuverability.
The Etruscans initially formed in 200 BC the small settlement of Fiesole (Faesulae in Latin), which was destroyed by Lucius Cornelius Sulla in 80 BC in reprisal for supporting the populares faction in Rome. The present city of Florence was established by Julius Caesar in 59 BC as a settlement for his veteran soldiers and was named originally Fluentia, owing to the fact that it was built between two rivers, which was later changed to Florentia ("flowering"). It was built in the style of an army camp with the main streets, the cardo and the decumanus, intersecting at the present Piazza della Repubblica. Situated along the Via Cassia, the main route between Rome and the north, and within the fertile valley of the Arno, the settlement quickly became an important commercial centre.
In centuries to come, the city experienced turbulent periods of Ostrogothic rule, during which the city was often troubled by warfare between the Ostrogoths and the Byzantines, which may have caused the population to fall to as few as 1,000 people. Peace returned under Lombard rule in the 6th century. Florence was conquered by Charlemagne in 774 and became part of the Duchy of Tuscany, with Lucca as capital. The population began to grow again and commerce prospered. In 854, Florence and Fiesole were united in one county.