Question: Which engineer born on May 16, 1899 helped develop the first truly successful V/STOL design of aircraft?
Sentence (from "Harrier Jump Jet"): Originally developed by UK manufacturer Hawker Siddeley in the 1960s, the Harrier emerged as the only truly successful V/STOL design of the many attempted during that era, despite being a subsonic aircraft, unlike most of its competitors.
Relevant evidence: Yes