Douglas SBD Dauntless
The Douglas SBD Dauntless is a World War II American naval scout plane and dive bomber that was manufactured by Douglas Aircraft from 1940 through 1944. The SBD was the United States Navy's main carrier-based scout/dive bomber from mid-1940 through mid-1944. The SBD was also flown by the United States Marine Corps, both from land air bases and aircraft carriers. The SBD is best remembered as the bomber that delivered the fatal blows to the Japanese carriers at the Battle of Midway in June 1942. The type earned its nickname "Slow But Deadly" during this period. Even though the SBD was ostensibly replaced by the Curtiss SB2C Helldiver in 1944, experience showed the earlier plane performed better, and both models fought side-by-side until the end of the war.
During its combat service, the SBD proved to be an effective naval scout plane and dive bomber. It possessed long range, good handling characteristics, maneuverability, potent bomb load, and great diving characteristics from the perforated dive brakes. A land-based variant of the SBD – omitting the arrestor hook — was purpose-built for the U.S. Army Air Forces, as the A-24 Banshee. However, due to lack of specialized training, the Army's experience wasn't as successful and by the middle months of 1943 the A-24 was considered by pilots to be too vulnerable for service owing to its armament and slow speed, and was relegated to non-combat roles.
Design and development
Design work on the Northrop BT-1 began in 1935. In 1937, the Northrop Corporation was taken over by Douglas, and the active Northrop projects continued under Douglas Aircraft Corporation. The Northrop BT-2 was developed from the BT-1 by modifications ordered in November 1937, and provided the basis of the SBD, which first entered service in mid-1939. Ed Heinemann led a team of designers who considered a development with a Wright Cyclone engine. The plane was developed at the Douglas El Segundo, California, plant, and that facility, along with the company's Oklahoma City plant, built almost all the SBDs produced. One year earlier, both the U.S. Navy and Marine Corps had placed orders for the new dive bomber, designated the SBD-1 and SBD-2. The SBD-1 went to the Marine Corps in late 1940, and the SBD-2 to the Navy in early 1941, replacing the SBU Corsair and Curtiss SBC Helldiver squadrons on US carriers. Distinctive perforated split flaps or "dive-brakes" had been incorporated into the BT-1 to eliminate tail buffeting during diving maneuvers. Unusual for carrier aircraft, folding wings were not chosen for the design, opting instead for structural strength.File:Dauntless bomb drop.jpg|thumb|A U.S. Navy SBD releasing a bomb with extended dive brakes on the trailing edges
The next version was the SBD-3, which began manufacture in early 1941. It had increased armor, self-sealing fuel tanks, and four machine guns. The SBD-4 provided a 12-volt electrical system, and a few were converted into SBD-4P reconnaissance aircraft.
The next version, the SBD-5, was produced mostly in the Douglas plant in Tulsa, Oklahoma. This version was equipped with a engine and an increased ammunition supply. Over 2,400 of these were built. A few of them were shipped to the Royal Navy for evaluation. In addition to American service, the SBD saw combat against the Japanese Army and Navy with No. 25 Squadron of the Royal New Zealand Air Force—but the RNZAF soon replaced them with the larger, faster, heavier and land-based Vought F4U Corsairs.
Some SBDs were also flown by the Free French Air Force against the German Heer and Luftwaffe. SBDs were also sold to Mexico.
The final version, the SBD-6, had more improvements, but its production ended during the summer of 1944.
The U.S. Army Air Forces had its own version of the SBD, called the A-24 Banshee. It lacked the tail hook used for carrier landings, and a pneumatic tire replaced the solid tail wheel. First assigned to the 27th Bombardment Group at Hunter Field, Georgia, A-24s flew in the Louisiana maneuvers of September 1941. There were three versions of the Banshee flown by the army to a very minor degree in the early stages of the war. The USAAF used 948 of the 5,937 Dauntlesses built.
Operational history
U.S. Navy and Marine Corps
U.S. Navy and Marine Corps SBDs saw their first action at Pearl Harbor, when most of the Marine Corps SBDs of Marine Scout Bombing Squadron 232 were destroyed on the ground at Ewa Mooring Mast Field. Most U.S. Navy SBDs flew from their aircraft carriers, which did not operate in close cooperation with the rest of the fleet. Most Navy SBDs at Pearl Harbor, like their Marine Corps counterparts, were destroyed on the ground. On 10 December 1941, SBDs from sank the Japanese submarine I-70. In February–March 1942, SBDs from the carriers,, and, took part in various raids on Japanese installations in the Gilbert Islands, the Marshall Islands, New Guinea, Rabaul, Wake Island, and Marcus Island.The first major use of the SBD in combat was at the Battle of the Coral Sea where SBDs and TBD Devastators sank the Japanese light aircraft carrier and damaged the Japanese fleet carrier. SBDs were also used for anti-torpedo combat air patrols and these scored several victories against Japanese aircraft trying to attack Lexington and Yorktown. Their relatively heavy gun armament with two forward-firing.50 BMG| M2 Browning machine guns and either one or two rear flexible-mount.30-06 Springfield| AN/M2 machine guns was effective against the lightly built Japanese fighters, and many pilots and gunners took aggressive attitudes to the fighters that attacked them. SBD pilot Stanley "Swede" Vejtasa was attacked by three A6M2 Zero fighters; he shot down two of them and cut off the wing of the third in a head-on pass with his wingtip.
The SBD's most important contribution to the American war effort came during the Battle of Midway in early June 1942. Four squadrons of Navy SBD dive bombers attacked and sank or fatally damaged all four Japanese fleet carriers present, disabling three of them in the span of just six minutes and, later in the day,. They also caught two straggling heavy cruisers of the Midway bombardment group of four, heavily damaging them, with eventually sinking.
At the Battle of Midway, Marine Corps SBDs were not as effective. One squadron, VMSB-241, flying from Midway Atoll, was not trained in the techniques of dive-bombing with their new Dauntlesses. Its pilots resorted to the slower but easier glide bombing technique. This led to many of the SBDs being shot down during their glide, although one survivor from these attacks is now on display at the National Naval Aviation Museum and is the last surviving aircraft to have flown in the battle. The carrier-borne squadrons were effective, especially when they were escorted by Grumman F4F Wildcats. The success of dive bombing resulted from one important factor,
SBDs played a major role in the Guadalcanal campaign, operating off both American carriers and from Henderson Field on Guadalcanal. SBDs proved lethal to Japanese shipping that failed to clear New Georgia Sound by daylight. Losses inflicted included the carrier, sunk near the Solomon Islands on 24 August. Three other Japanese carriers were damaged during the six-month campaign. SBDs sank a cruiser and nine transports during the Naval Battle of Guadalcanal.
In the Atlantic Ocean the SBD saw action during Operation Torch, the Allied landings in North Africa in November 1942. The SBDs flew from and two escort carriers. Eleven months later, during Operation Leader, the SBDs saw their European debut when aircraft from Ranger attacked Nazi German shipping around Bodø, Norway.
File:SBD-3 CV-4 Norway 1943 NAN10-1-45.jpg|thumb|A VB-4 SBD near Bodø, Norway, 4 October 1943
By 1944 the U.S. Navy began replacing the SBD with the more powerful SB2C Helldiver. During the Battle of the Philippine Sea in June 1944, a long range twilight strike was made against the retreating Japanese fleet, at the limit of the combat radius of the aircraft. The force had about twenty minutes of daylight over their targets before attempting the long return in the dark. Of the 215 aircraft, only 115 made it back. Twenty were lost to enemy action in the attack, and 80 were lost as one by one they expended their fuel and had to ditch into the sea. In the attack were 26 SBDs, all of which made it back to the carriers.
The Battle of the Philippine Sea was the last major engagement of the carrier-borne SBDs. Marine squadrons continued to fly SBDs until the end of the war. Although the Curtiss Helldiver had a more powerful engine, a higher maximum speed and could carry nearly a thousand pounds more in bomb load, many of the dive bomber pilots preferred the SBD, which was lighter and had better low-speed handling characteristics, critical for carrier landings.
The Dauntless was one of the most important aircraft in the Pacific War, sinking more enemy shipping in the Pacific than any other Allied bomber. Barrett Tillman, in his book on the Dauntless, claims that it has a "plus" score against enemy aircraft, meaning it was credited with more victories over enemy planes than losses from enemy action. This is considered to be a rare event for a nominal "bomber".
A total of 5,936 SBDs were produced during the war. The last SBD rolled off the assembly lines at the Douglas Aircraft plant in El Segundo, California, on 21 July 1944. The Navy placed emphasis on the heavier, faster and longer-ranged SB2C. From Pearl Harbor through April 1944, SBDs had flown 1,189,473 operational hours, with 25 percent of all operational hours flown off aircraft carriers being in SBDs. Its battle record shows that in addition to six Japanese carriers, 14 enemy cruisers had been sunk, along with six destroyers, 15 transports or cargo ships and scores of various lesser craft.