08/15/2008. Remarks by Ray Watkins: "Lawrence Bell wanted to overcome the compromise between vertical flight capability and horizontal speed, and initiated research into 'convertiplanes'. The US Army held a design competition for 'convertiplanes' in 1950 and contracts were awarded to three companies: McDonnell (for the XV-1), Sikorsky (for the XV-2) and Bell for the XV-3.

The maiden flight of the first trial vehicle (54-157) occurred on 23 August 1955. The second pictured aircraft (54-148) was completed in April 1955, with two-blade rotors (instead of three-blade on 54-157) and a large ventral fin under the tail."