When was the first test flight of the B-2A stealth strategic bomber? What are its performance characteristics?

B-2A is a stealth strategic bomber developed by Northrop Corporation. It was secretly developed by 1978 according to the requirements of the US Air Force. At the end of 1987, Northrop won a contract worth $2 billion and began to produce B-2A. B-2A adopts flying wing layout, with straight leading edge and sweepback angle of 33. The trailing edge of the double W-shape has eight control surfaces. This unique aerodynamic layout not only has the advantage of large lift coefficient, but also meets the requirements of maneuverability and stealth characteristics. In addition to the flying wing layout, the aircraft also adopts advanced composite materials such as graphite and carbon fiber, honeycomb radar absorbing structure, radar absorbing material coating and sawtooth radar scattering structure, which further reduces the radar reflection cross-sectional area. It is said that the radar reflection cross section of B-2A is equivalent to that of a bird at normal detection distance. In addition, the B-2A has also taken a series of infrared and visible stealth measures, such as putting the tail nozzle on the upper part of the fuselage and using the afterburner turbofan engine. Special substances are added to the fuel to reduce the wake. The main operational task of B-2A is to use its excellent stealth performance to break through the enemy air defense system from high altitude or low altitude and carry out nuclear bombing or conventional bombing on strategic targets. This plane can refuel in the air. The prototype of B-2A 1988 1 1 Factory1October, 1989 made its first test flight. The original purchase of 133 B-2A aircraft by the US Air Force has been reduced to 75. Due to the changes in the international situation and the high procurement cost of B-2A, there has been a debate in the United States about whether B-2A will be put into production. Based on the production batch of 132 aircraft, the stand-alone price of B-2A is $274 million or $530 million.