placed in December. As Vultee's factory at Downey was already busy building BT-13 Valiant trainers, the aircraft were to be built at the Stinson factory at Nashville, and under license by Northrop at Hawthorne, California. The first prototype V-72 flew from Vultee's factory at Downey, California, on 30 March 1941. Additional aircraft were ordered for Britain in June 1941 under the Lend-Lease scheme, with those being given the US Army Air Corps designation A-31. After the U.S. entered the war following the attack on Pearl Harbor, a number of V-72 and A-31 aircraft were repossessed for use by the USAAF. As the USAAF became interested in dive bombing, it decided to order production of an improved version of the Vengeance, designated the A-35, for both its own use and for supply to its allies under Lend-Lease. It was fitted with a more powerful Wright Twin Cyclone R-2600-19 engine and improved armament. As US Army test pilots disliked the poor pilot view resulting from the zero-incidence wing, that was "corrected" in the A-35, giving the plane a better attitude in cruise but lessening its accuracy as a dive bomber. When production of the Vengeance was completed in 1944, a total of 1,931 aircraft had been made. The majority were produced at the Vultee plant in Nashville, Tennessee. Indecision about which aircraft type should replace it in production at the Vultee plant led to several "make-work" contracts for Vengeance aircraft to prevent dispersion of the skilled workforce. That resulted in the overproduction of what was considered an obsolete aircraft. Evaluation Operational experience with other dive bomber aircraft of the period, such as the Blackburn Skua, Junkers Ju 87 Stuka, Aichi D3A "Val", Douglas Dauntless, Breda Ba.65 and Curtiss SB2C Helldiver, indicated that the Vengeance would be vulnerable to enemy fighters. To be effective, all those aircraft required an environment of local air superiority and fighter escort. Fighter escort and lack of fighter opposition in the theatres in which it served, combined with its vertical dive capability, meant that the Vengeance suffered only light combat losses. Early experience with the aircraft showed that there were problems with engine cooling. In service, the RAF managed to solve those problems, but Free French aircraft that did not have these problems remedied were grounded, being declared uneconomical and unreliable to operate. The aircraft was described as being stable in flight and in a dive, with heavy