 Complete the following phrase:  Concern over the USAAFs inability to escort B-29s all the way to mainland Japan resulted in the highly classified Seahorse project NAA-133, an effort to navalize the P-51. On 15 November 1944, naval aviator and later test pilot Lieutet Bob Elder, in a P-51D-5-NA 44-14017, started flight tests from the deck of the carrier . This Mustang had been fitted with an arrestor hook, which was attached to a reinforced bulkhead behind the tail wheel opening; the hook was housed in a streamlined position under the rudder fairing and could be released from the cockpit. The tests showed that the Mustang could be flown off the carrier deck without the aid of a catapult, using a flap setting of 20 down and 5 of up elevator. Landings were found to be easy, and, by allowing the tail wheel to contact the deck before the main gear, the aircraft could be stopped in a minimum distance. The project was canceled after 