Vought SB2U Vindicator

The Vought SB2U Vindicator is an American carrier-based dive bomber developed for the United States Navy in the 1930s, the first monoplane in this role. Obsolete at the outbreak of World War II, Vindicators still remained in service at the time of the Battle of Midway, but by 1943, all had been withdrawn to training units. It was known as the Chesapeake in Royal Navy service. 
==Design and development==
In 1934, the United States Navy issued a requirement for a new Scout Bomber for carrier use, and received proposals from six manufacturers. The specification was issued in two parts, one for a monoplane, and one for a biplane. Vought submitted designs in both categories, which would become the XSB2U-1 and XSB3U-1 respectively. The biplane was considered alongside the monoplane design as a "hedge" against the U.S. Navy's reluctance to pursue the modern configuration.[1] 
The XSB2U-1 was of conventional low-wing monoplane configuration with a retractable conventional tailwheel landing gear, the pilot and tail gunner being seated in tandem under a long greenhouse-style canopy. The fuselage was of steel tube construction, covered with aluminum panels from the nose to the rear cockpit with a fabric-covered rear fuselage, while the folding cantilever wing was of all-metal construction. A Pratt & Whitney R-1535 Twin-Wasp Junior radial engine drove a two-blade constant-speed propeller, which was intended to act as a dive brake during a dive bombing attack. A single 1,000 lb (450 kg) bomb could be carried on a swinging trapeze to allow it to clear the propeller in a steep dive, while further bombs could be carried under the wings to give a maximum bombload of 1,500 lb (680 kg).[2][3] 
The SB2U was evaluated against the Brewster XSBA-1, Curtiss XSBC-3, Great Lakes XB2G-1, Grumman XSBF-1 and Northrop XBT-1. All but the Great Lakes and Grumman submissions were ordered into production. Designated XSB2U-1, one prototype was ordered on 15 October 1934 and was delivered on 15 April 1936. Accepted for operational evaluation on 2 July 1936, the prototype XSB2U-1, BuNo 9725, crashed on 20 August 1936.[4] Its successful completion of trials led to further orders.[1] 
The SB2U is prominently featured in the 1941 film Dive Bomber. 
There were 260 examples of all Vindicator variants produced, and a single example is preserved at the National Naval Aviation Museum at NAS Pensacola, Florida. 
==Operational history==
===U.S. Navy===
Vindicators served on the carriers Lexington, Saratoga, Ranger, and Wasp from December 1937-September 1942. Air Group Nine, destined for Essex, trained in Vindicators aboard the escort carrier Charger, but they transitioned to the Douglas SBD Dauntless before Essex joined the war.[1] 
During the attack on Pearl Harbor, seven Vindicators from the U.S. squadron VMSB-231 were destroyed at Ewa Field. 
===U.S. Marine Corps===
VMSB-131 and VMSB-241 were the only two USMC squadrons that fielded the Marine-specific SB2U-3 between March 1941 and September 1943. VMSB-241's Vindicators saw combat at the Battle of Midway in June 1942.[5] Airmen with experience in more modern aircraft spoke disparagingly of SB2Us as "vibrators" or "wind indicators" in their later combat assignments.[6][7] Captain Richard E. Fleming piloted a SB2U-3 Vindicator in an attack on the Japanese cruiser Mikuma on 5 June 1942, for which he was posthumously awarded the Medal of Honor.
===French Navy===
Based on the SB2U-2, the V-156-F incorporated specific French equipment. Briefly after the deliveries started in July 1939, V-156-F crews were trained for carrier operations aboard the French carrier Béarn, but when the war broke out the old carrier was declared too slow for operational service. As a result, V-156-F-equipped units escadrilles AB 1 and AB 3 were based ashore when the Battle of France started. AB 1 sustained heavy losses while attacking bridges and German ground targets in Northern France, as well as providing air cover for the Evacuation of Dunkirk. AB 3's V-156-Fs were briefly engaged against the Italians, during which time they were credited with possibly sinking one submarine off Albenga. By the time of the Armistice, there were only a handful of remaining Voughts in French hands, and the type was phased out of service.
===Royal Navy===
France had placed an order for a further 50 V-156-Fs in March 1940, with delivery planned from March 1941. Following the defeat of France, this order was taken over by the British government for use by the Royal Navy's Fleet Air Arm, who named the aircraft the Chesapeake.[9] The British required several modifications to the Chesapeake, including the additional fuel tank fitted to the SB2U-3,[9] additional armor and heavier forward firing armament, with four rifle caliber machine guns replacing the single forward-firing Darne machine gun of the French aircraft.[10] Fourteen Chesapeakes were used to equip a reformed 811 Naval Air Squadron on 14 July 1941 at RNAS Lee-on-Solent.[11] The squadron, whose crews referred to it as the "cheesecake", intended to use them for anti-submarine patrols, and they were earmarked for the escort carrier HMS Archer. 
By the end of October that year, it had been decided that the Chesapeakes were underpowered for the planned duties and would not be able to lift a sensible payload from the small escort carriers. Accordingly, they were withdrawn from 811 Squadron in November 1941 for use as training aircraft and the unit was re-equipped with the biplane Fairey Swordfish. 
==Variants==
==Operators==
The Vought SB2U Vindicator was an early monoplane dive bomber used by the Allies during the early months of World War 2.
==Description==
The Vindicator was a decent aircraft when it was accepted in 1936 as the U.S. Navy's first monoplane scout bomber. It was the product of a call for comparative trials between a modern biplane and modern monoplane design. The monoplane design proved much superior and was put into production in October 1936. Deliveries began in December 1937.
A small number were ordered by the French as the V-156F, and 24 had been delivered by May 1940. Half of these were wiped out on the first day of the German invasion. The remaining French aircraft were used in battle against the invading Germans, and were briefly used against Italy as well. Those aircraft not yet delivered to the French were taken over by the British, who ordered an additional 50 as the Chesapeake Mark I.
The Vindicator was clearly obsolete by the start of the Pacific War. A few –3s saw action with the Marines at Midway, suffering relatively light casualties but failing to get any hits. Its crews sardonically referred to it as the "Wind Indicator." Pacific War Encyclopedia
==Specification==
* Crew: 2
* Dimensions: 41'11" (12.78m) by 33'11.75" (10.36m) by 14'3" (4.34m)
* Wing area: 305 square feet (28.3 square meters)
* Weight: 5634-9763 lbs (2556-4428 kg)
* Maximum speed: 243 mph (391 km/h) at 9500 feet (2900 meters), 232 mph (373 km/h) at sea level
* Cruise speed: 152 mph (245 km/h)
* Landing speed: 71 mph (114 km/h)
* Climb rate: 18 feet per second (5.5 meters per second)
* Service ceiling: 23,600 feet (7200 meters)
* Power plant: One 750 hp (559 kW) Pratt & Whitney R-1535-02 Twin Wasp Junior 14-cylinder two-row radial driving a two bladed propeller.
* Armament: One 0.50 fixed wing machine gun, One 0.50 flexible rear cockpit machine gun
* External stores: 1000 lbs (454 kg) of bombs
* Range: 1120 miles (1800 km) with bomb load, 2450 miles (3940 km) as ferry
* Fuel: 538 gallons (2037 liters)
* Production: Vought-Sikorsky Division of United Aircraft, East Hartford, CT, comprising 54 –1s, 58 –2s and 57 –3s.
==References==
Category:Between the wars
Category:American
Category:Piston engined
Category:Single engine
Category:World War 2
Category:Monoplane
Category:Carrier based
Category:Dive Bomber