Vultee A-31 Vengeance

In 1940, Vultee Aircraft started the design of a single-engined dive-bomber, the Vultee Model 72 (V-72) to meet the requirements of the French ''Armée de l'Air''. The V-72 was built with private funds and was intended for sale to foreign markets. The V-72 was a low-wing, single-engine monoplane with a closed cockpit and a crew of two. An air-cooled radial Wright Twin Cyclone engine rated at powered the V-72. It was armed with fixed forward-firing and flexible-mounted machine guns in the rear cockpit. The aircraft carried up to of bombs in an interior bomb bay and on external wing racks. The Vengeance was uniquely designed to dive vertically without lift from the wing pulling the aircraft off target. To this end, the wing had a 0° angle of incidence the better to align the nose of the aircraft with the target during the dive. This resulted in the aircraft cruising in a nose-up attitude, giving a poor forward view for the pilot, particularly during landing. It had an unusual, W-shaped wing planform. This resulted from an error in calculating its centre of gravity. Moving the wing back by "sweeping" the centre section was a simpler fix than re-designing the wing root. This gives the impression of an inverted gull wing when seen from an angle, when in fact the wing has a more conventional dihedral on the outer wing panels. France placed an order for 300 V-72s, with deliveries intended to start in October 1940. The Battle of France in June 1940 stopped these plans, but at the same time the British Purchasing Commission, impressed by the performance of the German Junkers Ju 87, "Stuka" was shopping for a dive bomber for the Royal Air Force, and as it was the only aircraft available, placed an order for 200 V-72s (named Vengeance by Vultee) on 3 July 1940, with orders for a further 100 being 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 licence 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 given the US Army Air Corps name A-31. After the US 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, 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-bombers, 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 fighter attack. To be effective, all those aircraft required an environment of local air superiority and fighter escort. Escorts 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. The RAF managed to solve the 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 elevator and rudder control , the aileron control was considered light. Forward visibility was considered poor due to the large radial engine. There were a number of fatal accidents with the Vengeance due to improper dive procedures, as well as a center of gravity problem when the aircraft was flown with the rear cockpit canopy open and without a rear gunner. The type was considered rugged, reliable, stable and generally well-behaved. Commonwealth forces operated the type from May 1942 to July 1944. Burma tended to have low importance for Allied air planners and forces in that theatre got left overs. Aircraft such as the Wellington and Hurricane spent their last days in Burma. The Vengeance saw considerable action attacking Japanese supply, communications and troop concentrations. Its service in that theatre has been described as "...very effective". Peter Smith, author of Jungle Dive Bombers at War, wrote that, "Their pilots had difficulty in getting them off the ground with a full load. At Newton Field they were using the full length of the runway before becoming airborne. Kittyhawk aircraft could carry the same bomb load and in addition carry out ground-strafing". In contrast, many crew spoke well of the Vengeance, ==Operational history==