  a semi-automatic transmission (sat) (also known as a clutchless manual transmission, automated manual transmission, flappy-paddle gearbox, or paddle-shift gearbox) is an automobile transmission that does not change gears automatically, but rather facilitates manual gear changes by dispensing with the need to press a clutch pedal at the same time as changing gears. it uses electronic sensors, pneumatics, processors and actuators to execute gear shifts on input from the driver or by a computer. this removes the need for a clutch pedal which the driver otherwise needs to depress before making a gear change, since the clutch itself is actuated by electronic equipment which can synchronise the timing and torque required to make quick, smooth gear shifts. the system was designed by automobile manufacturers to provide a better driving experience through fast overtaking maneuvers on highways. ==early semi-automatic transmissions==  in the 1930s, automakers began to market cars with some sort of device that would reduce the amount of clutching and de-clutching and shifting required in stop and go driving. most typically, a fluid coupling or a centrifugal clutch replaced the standard manual clutch to allow for stop and go driving without using the clutch pedal every time the car was brought to a stop. more sophisticated systems allowed for shifting while driving without using the clutch, and some systems did away with the clutch pedal altogether. semi-automatic transmissions were phased out as technology advanced and automatic controls were developed to take care of changing gear ratios. smaller, lower powered cars used semi-automatic transmissions with a dry clutch because the mechanical connection offered a more efficient powertrain compared to a fluid coupling. another early semi-automatic transmission was the sinclair s.s.s. (synchro-self-shifting) powerflow gearbox. which was applied to huwood-hudswell diesel mines locomotives. it was also applied to some road vehicles. it is covered by us patent 2505842. ==comparison to other automated transmissions== modern "semi-automatic trans
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