|SBD Dauntless |
|A U.S. Navy SBD releasing a bomb. Note the extended dive brakes on the trailing edges.|
|National origin||United States|
|First flight||1 May 1940|
|Primary users||United States Navy|
United States Marine Corps
United States Army Air Forces
Free French Air Force
Royal New Zealand Air Force
|Developed from||Northrop BT|
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 ("Scout Bomber Douglas") 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" (from its SBD initials) during this period.
During its combat service, the SBD proved to be an excellent naval scout plane and dive bomber. It possessed long range, good handling characteristics, maneuverability, potent bomb load, great diving characteristics from the perforated dive brakes, good defensive armament, and ruggedness. One 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.
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 1,000 hp (750 kW) 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 latter had increased fuel capacity and different armament). 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.
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 (up from 6-volt) electrical system, and a few were converted into SBD-4P reconnaissance aircraft.
The next (and most produced) version, the SBD-5, was produced mostly in the Douglas plant in Tulsa, Oklahoma. This version was equipped with a 1,200 hp (890 kW) 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,[clarification needed] but its production ended during the summer of 1944.
The U.S. Army Air Force 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 (Light) at Hunter Field, Georgia, A-24s flew in the Louisiana maneuvers of September 1941. There were three versions of the Banshee (A-24, A-24A and A-24B) 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.
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 (VMSB-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 USS Enterprise sank the Japanese submarine I-70. In February–March 1942, SBDs from the carriers USS Lexington, USS Yorktown, and USS Enterprise, 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 (CVL) Shōhō and damaged the Japanese fleet carrier Shōkaku. SBDs were also used for anti-torpedo combat air patrols (CAP) and these scored several victories against Japanese aircraft trying to attack Lexington and Yorktown. Their relatively heavy gun armament with two forward-firing .50 in (12.7 mm) M2 Browning machine guns and either one or two rear flexible-mount .30 in (7.62 mm) 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. [N 1]
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 (Akagi, Kaga, Sōryū) and, later in the day, Hiryū. They also caught two straggling heavy cruisers of the Midway bombardment group of four, heavily damaging them, with Mikuma 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 (having just partially converted from the SB2U Vindicator). 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 fly in the battle. The carrier-borne squadrons were effective, especially when they were escorted by Grumman F4F Wildcats. The success of dive bombing was due to one important circumstance:
Unlike American squadrons that attacked shortly before one at a time, allowing defending Japanese Zero fighters to concentrate on each squadron to shoot them down or drive them away from the carriers, three squadrons totaling 47 SBDs (VS-6, VB-6, and VB-3), one squadron of 12 TBD torpedo aircraft (VT-3), and six F4F fighters (from VF-3) all arrived simultaneously, with two of the SBD squadrons (VS-6 and VB-6) arriving from a different direction from the other squadrons. Without central fighter direction, the approximately 40 Zeros concentrated on the TBDs, with some fighting the F4Fs covering the TBDs, leaving the SBDs unhindered by fighter opposition in their approach and attack (although most of the TBDs were shot down).
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 (the slot) by daylight. Losses inflicted included the carrier Ryūjō, 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.
The SBD's strengths and weaknesses became evident. While the American strength was dive bombing, the Japanese stressed their Nakajima B5N2 "Kate" torpedo bombers, which had caused the bulk of the damage during the Japanese attack on Pearl Harbor.
In the Atlantic Ocean the SBD saw action during Operation Torch, the Allied landings in North Africa in November 1942. The SBDs flew from USS Ranger 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.
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 (or beyond) 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 when 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 due to 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.
The U.S. Army Air Forces sent 52 A-24 Banshees in crates to the Philippines in the fall of 1941 to equip the 27th Bombardment Group, whose personnel were sent separately. However, after the Japanese attack on Pearl Harbor, these bombers were diverted to Australia and the 27th BG fought on the Bataan Peninsula as infantry. While in Australia the aircraft were reassembled for flight to the Philippines but their missing parts, including solenoids, trigger motors and gun mounts delayed their shipment. Plagued with mechanical problems, the A-24s were diverted to the 91st Bombardment Squadron and designated for assignment to Java Island instead.
Referring to themselves as "Blue Rock Clay Pigeons" (after a brand of trap shooting targets), the 91st BS attacked the enemy harbor and airbase at Bali and damaged or sank numerous ships around Java. After the Japanese downed two A-24s and damaged three so badly that they could no longer fly, the 91st received orders to evacuate Java in early March.
The A-24s remaining in Australia were assigned to the 8th Bombardment Squadron of 3d Bombardment Group, to defend New Guinea. On 29 July 1942, seven A-24s attacked a convoy off Buna, but only one survived: the Japanese shot down five of them and damaged the sixth so badly that it did not make it back to base. Regarded by many pilots as too slow, short ranged and poorly armed, the remaining A-24s were relegated to non-combat missions. In the U.S., the A-24s became training aircraft or towed targets for aerial gunnery training. The more powerful A-24B was used later against the Japanese forces in the Gilbert Islands. From December 1943 until March 1944, the 531st Fighter Squadron of the 7th Air Force flew A-24Bs from Makin Island in the Gilbert Islands against Japanese controlled islands in the Marshall Islands. The A-24Bs were then withdrawn from combat.
The A-24B (equivalent to the U.S. Navy SBD-5, with the omission of the arrestor hook) arrived in 1943 with the more powerful 1,200-hp Wright R-1820-60 Cyclone engine, a more powerful engine than either the A-24 or A-24A. As a result, the A-24B could fly slightly faster and higher than the earlier models. The A-24B lacked the small air intake on the top of the engine cowling present on the earlier models and that is an easy way to distinguish the B model. The 407th Bomb Group, assigned to the 11th Air Force, flew A-24Bs against the Japanese held island of Kiska, Alaska, during July and August 1943.
A handful of A-24s survived in the inventory of the USAAF long enough to be taken over by the Air Force (USAF) when that service became independent of the Army in September 1947. The USAF established a new designation system for its aircraft, eliminating the "A-" (for attack) category (through 1962); all of the single-engined "A-" aircraft were given "F-" (for fighter) nomenclature (or were determined to be obsolete and scrapped); thus the few remaining A-24 Banshees became known as F-24 Banshees, soldiering on in a reserve role until 1950 when they were scrapped.
The first production Dauntless sent into action was the "SBD-3", which was produced for the French Naval Aviation. A total of 174 Dauntlesses were ordered by the French Navy, but with the fall of France in the spring of 1940 that production batch was diverted to the U.S. Navy, which ordered 410 more.
The Free French received about 80 SBD-5s and A-24Bs from the United States in 1944. They were used as trainers and close-support aircraft.
Squadron I/17 Picardie used a few A-24Bs for coastal patrol. The most combat-experienced of the Banshee units was GC 1/18 Vendee, which flew A-24Bs in support of Allied forces in southern France and also experienced how deadly German flak was, losing several aircraft in 1944. This squadron flew from North Africa to recently liberated Toulouse to support Allied and French resistance troops. Later, the unit was assigned to support attacks on cities occupied by the Germans on the French Atlantic coast. In April 1945 each SBD-5 averaged three missions a day in the European theater. In 1946 the French Air Force based its A-24Bs in Morocco as trainers.
French Navy Dauntlesses were based in Cognac at the end of 1944. The French Navy Dauntlesses were the last ones to see combat, during the Indochina War, flying from the carrier Arromanches (the former Royal Navy carrier Colossus). In late 1947 during one operation in the Indochina War, Flotille 4F flew 200 missions and dropped 65 tons of bombs. By 1949, the French Navy removed the Dauntless from combat status although the type was still flown as a trainer through 1953.
The Royal New Zealand Air Force received 18 SBD-3s and 23 SBD-4s and No. 25 Squadron RNZAF used them in combat over the South Pacific. Under the original plan, four Squadrons (25, 26, 27 and 28) of the RNZAF were going to be equipped with the Dauntless but only 25 Squadron used them. The RNZAF soon replaced them with F4U Corsairs.
The hyphenated numbers are original U.S. Army Air Forces Serial Numbers (AAF Ser. No.); four or five digit numbers are original U.S. Navy Bureau of Aeronautics (BuAer) Bureau Numbers (BuNo).
Data from McDonnell Douglas aircraft since 1920 : Volume I
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