A wargame conducted by the Mitchell Institute for Aerospace Studies suggested that a stand-in, penetrating force of the future Boeing [BA] F-47 stealth fighter for counter air and the Northrop Grumman [NOC] B-21 Raider stealth bomber for strategic attack were key to blunting a Chinese invasion of Taiwan, according to a report released by the institute on Thursday. Mitchell is advising the Air Force to buy 300 F-47s and at least 150 B-21s. In the wargame set in 2035, two…