IN NATURE of Sept. 8, p. 349, Mr. A. S. E. Ackermann asks this question. For many years it has been the practice in this Department to dip the fingers into molten lead when lecturing on the ...

NASA's F/A-18 (left) and X-31 are among the airplanes used to gather data for thrust-vectoring ... Pete “Maverick” Mitchell gets the upper hand on his instructors by slowing down, pulling ...