Ceratonia siliqua harubh. "Ceratonia siliqua", the scientific name of the carob tree, derives from the Greek "kerátiοn" κεράτιον 'fruit of the carob (from "keras" κέρας 'horn'), and Latin "siliqua" 'pod, carob'. The unit "carat", used for weighing precious metal and stones, also comes from κεράτιον, as alluding to an ancient practice of weighing gold and gemstones against the seeds of the carob tree by people in the Middle East. The system was eventually standardized, and one carat was fixed at 0.2 grams. In late Roman times, the pure gold coin known as the "solidus" weighed 24 carat seeds (about 4.5 grams). As
AMS-Flight Carat feather the propeller blades. The Carat's propeller is opened by the centrifugal force on the turning blades, working against a folding force provided by a gas damping spring mechanism. This folding mechanism has the advantage of simplicity, but it means that the engine can not be windmill-started if the battery is flat. Because of the forward pointing blades when the engine is off, the Carat cannot be towed aloft like traditional sailplanes. The first flight was made on 16 December 1997 and the first production model displayed at Aero '99 at Friedrichshafen in April 1999 as the Technoflug TFK-2 Carat.