Correct answer is... 805 km/h. It is equal to 435 kn or 500 mph. It is higher value then max speed of other aircrafts of a similar size. Average is about 230 km/h (124 kn or 143 mph).
The maximum speed most frequently is a term for so-called never exceed speed. Above this speed, the Messerschmitt Me 328 can suffer considerable damage. There are also three other types of speed that can be called "maximum speed": Vno (normal operation speed) is the maximum allowable speed of normal operation, Vb (design speed for maximum gust intensity) is the maximum speed in rough air, and Va (design maneuvering speed) is the maximum speed at which the rudders can be maximally deflected.
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