Vought SB2U Vindicator

The Vought SB2U Vindicator was a carrier-based dive bomber developed for the United States Navy in the 1930s, the first monoplane in this role. Obsolescent 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of World War II, Vindicators still remained in service at the time of the Battle of Midway, but by 1943, all had been withdrawn to training units.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.

The XSB2U-1 was of conventional low-wing monoplane configuration, with a retractable tailwheel undercarriage and the pilot and tail gunner 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, and 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).

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. Its successful completion of trials led to further orders.

There were 260 examples of all Vindicator variants produced, and a single example is preserved at the National Museum of Naval Aviation at NAS Pensacola.

U.S. Navy


Vindicators served on four carriers, USS Lexington (CV-2), USS Saratoga (CV-3), USS Ranger (CV-4), and USS Wasp (CV-7) between December 1937 and September 1942. Air Group Nine, destined for USS Essex (CV-9), trained in Vindicators aboard the auxiliary carrier USS Charger (CVE-30) but transitioned to the SBD Dauntless before Essex joined the war.

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. Airmen with experience in more modern aircraft spoke disparagingly of SB2Us as "vibrators" or "wind indicators" in their latter combat assignments.

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 FRENCH AIRCRAFT 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, while AB 3's V-156-Fs were briefly engaged against the Italians. 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. The British required several modifications to the Chesapeake, including the additional fuel tank fitted to the SB2U-3, additional armour and heavier forward firing armament, with four rifle calibre machine guns replacing the single forward firing Darne machine gun of the French aircraft. Fourteen Chesapeakes were used to equip a reformed 811 Naval Air Squadron on 14 July 1941. The squadron, whose crews referred to it as the "cheesecake", was intended to use them for anti-submarine patrols and was earmarked for the escort carrier HMS Archer (D78).

By the end of October that year, it had been decided that the Chesapeakes were under-powered for the planned duties and would not be able to lift a sensible warload 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

 * XSB2U-1
 * Single prototype, powered by a 750hp R-1535-78 engine.


 * SB2U-1
 * Initial production version powered by a 825hp R-1535-96 engine, 54 built.


 * SB2U-2
 * Same as SB2U-1 but with minor equipment changed, 58 built.


 * XSB2U-3
 * Single prototype of the extended-range version with twin floats, converted from the SB2U-1.


 * SB2U-3
 * Similar to the SB2U-2 but fitted with a 825hp R-1535-102 engine, crew armour and two 0.5in guns, 57 built


 * V-156F-3
 * Export version for the French Navy, 40 built.


 * V-156B-1
 * Export version similar to the SB2U-3 and powered by a 750hp R-1535-SB4-G engine for the British Royal Navy. Designated Chesapeake Mk.I; 50 built.


 * V-167
 * The V-156 company demonstrator was fitted with a more powerful Pratt & Whitney R-1830 engine and redesignated V-167. It remained an one-off.

Operators



 * French Navy Aeronavale
 * Royal Navy Fleet Air Arm
 * 768 Naval Air Squadron
 * 770 Naval Air Squadron
 * 771 Naval Air Squadron
 * 772 Naval Air Squadron
 * 776 Naval Air Squadron
 * 778 Naval Air Squadron
 * 781 Naval Air Squadron
 * 784 Naval Air Squadron
 * 786 Naval Air Squadron
 * 811 Naval Air Squadron
 * United States Navy
 * United States Marine Corps
 * United States Navy
 * United States Marine Corps
 * United States Marine Corps

Survivors
Only one known survivor exists today:
 * SB2U-2 Vindicator, bureau number 1383, is on display at the National Museum of Naval Aviation at NAS Pensacola.