SBD Dauntless

1. Lead

The SBD Dauntless was the dive bomber that won the Battle of Midway, and one of the most important aircraft of the Pacific War. Designed by the Douglas Aircraft Company and nicknamed “Slow But Deadly” by its crews, the SBD was a slow, ungainly-looking aircraft that could do one thing supremely well: dive almost vertically onto a target, release a 1,000-pound bomb with great accuracy, and pull out of the dive to fight its way home. On 4 June 1942, at Midway, SBDs from the American carriers Enterprise, Yorktown and Hornet sank all four Japanese fleet carriers — Akagi, Kaga, Soryu and Hiryu — in a few hours, and changed the course of the Pacific War. About 5,936 SBDs were built, and they served from the first months of the war to the last, in the Coral Sea, at Midway, at Guadalcanal and in the Philippines. The SBD was slow, it was vulnerable to fighters, and it was replaced by the faster SB2C Helldiver in 1944, but no other dive bomber of the war sank as many ships, and no other aircraft did as much to win a single battle.

2. Key Facts

Type	Carrier-based dive bomber (and scout)
Origin	United States
Designer	Douglas Aircraft Company (Ed Heinemann)
Manufacturer	Douglas Aircraft Company, El Segundo, California
First flight	1 May 1940 (SBD-1; developed from the Northrop BT-1)
Introduced	1940
Produced	1940–1944; 5,936 built
Crew	2 (pilot and rear gunner / radio operator)
Length	10.1 m (SBD-5)
Wingspan	12.7 m
Height	4.1 m
Empty weight	About 2,905 kg (SBD-5)
Maximum take-off weight	About 4,850 kg (SBD-5)
Engine	Wright R-1820-60 Cyclone radial, 1,200 hp (SBD-5)
Maximum speed	About 410 km/h
Range	About 1,795 km
Service ceiling	About 7,800 m
Armament	2 × 12.7 mm (.50 cal) machine guns forward; 1–2 × 7.62 mm (.30 cal) machine guns in the rear cockpit
Bomb load	1 × 1,000 lb (450 kg) bomb under the fuselage, plus 2 × 100 lb bombs under the wings
Nickname	“Slow But Deadly”

3. Background and Development

The Dive-Bomber Idea

The SBD was born of the United States Navy’s belief, in the 1930s, that the dive bomber was the most accurate way to attack a ship. A level bomber, dropping its bombs from high altitude, had little chance of hitting a moving ship, but a dive bomber, diving steeply onto its target and releasing its bomb at low altitude, could hit a ship with a high degree of accuracy. The Navy’s first dive bombers were the biplanes of the 1930s, but by the end of the decade it wanted a modern, all-metal monoplane, and the Douglas Aircraft Company, under its chief designer Ed Heinemann, answered with a development of the Northrop BT-1, a dive bomber that had entered service in 1938. The new aircraft, which was designated SBD — “Scout Bomber, Douglas” — first flew on 1 May 1940, and it entered service with the Navy and the Marine Corps later that year. The SBD was the first American dive bomber to be designed from the start as a monoplane, and it was the aircraft that the Navy would take into the Pacific War.

From the BT-1 to the SBD

The SBD was developed from the Northrop BT-1, which had been designed by Ed Heinemann at Northrop and which had entered service in 1938. The BT-1 was a good aircraft, but it had a serious problem: it was difficult to recover from a dive, because its controls became heavy and because its airframe was not strong enough for the stresses of a steep dive. Heinemann, who had moved to Douglas when Douglas bought Northrop’s El Segundo plant, redesigned the aircraft as the SBD, with a stronger airframe, with perforated dive brakes on the wings — flaps with holes in them, which slowed the dive without making the aircraft unstable — and with a more powerful engine. The SBD-1, the first production version, was delivered to the Marine Corps in 1940, and the SBD-2, SBD-3 and SBD-5 followed, each with a more powerful engine, more fuel and heavier armament. The SBD-5, which was the most-produced version, accounted for 2,965 aircraft, more than half of all SBDs built.

The Scout-Bomber

The “S” in SBD stood for “Scout”, and the SBD was designed to be both a scout and a bomber. In the Navy’s doctrine, the SBDs of a carrier’s air group would fly ahead of the carrier, search for the enemy fleet, and then attack it, and the aircraft’s long range — about 1,795 km — made it well suited to the scouting role. The SBD’s rear cockpit, with its gunner and its radio, was designed for the scouting role as much as for defence: the gunner could observe the sea, report the enemy’s position by radio, and defend the aircraft with his machine guns. The SBD’s dual role was a strength and a weakness: it made the aircraft versatile, but it also meant that the SBD was slower and heavier than a pure dive bomber would have been, and its crews called it “Slow But Deadly” — slow, but deadly when it dived on its target. The nickname was affectionate, and it was accurate: the SBD was slow, but its bombs rarely missed.

4. Design

The Dive Brakes and the Dive

The SBD’s most important design feature was its dive brakes: perforated flaps on the trailing edge of the wings, which the pilot extended before diving, and which slowed the aircraft’s dive to a speed at which the pilot could aim accurately and at which the airframe would not be overstressed. The dive brakes were the key to the SBD’s accuracy: without them, the aircraft would have dived too fast, the pilot would have had too little time to aim, and the pull-out from the dive would have imposed stresses that the airframe could not withstand. The SBD’s dive was a carefully choreographed manoeuvre: the pilot approached the target at about 4,500 metres, rolled into a dive of 70 degrees or more, extended the dive brakes, aimed through his telescopic sight, released his bomb at about 600 metres, and pulled out of the dive at about 5 g — five times the force of gravity — to climb away from the target. The manoeuvre required skill and nerve, and the SBD’s pilots were among the most skilled in the Navy.

The Airframe and the Engine

The SBD was a low-wing monoplane of all-metal construction, with a Wright R-1820 Cyclone radial engine of 1,000 horsepower in the early versions and 1,200 horsepower in the SBD-5. Its wing was a two-spar structure, its fuselage was a semi-monocoque structure, and its landing gear was fixed — a feature that made the aircraft slower than it might have been, but that also made it simpler, stronger and easier to maintain on a carrier. The SBD’s fixed landing gear, with its large, spatted wheels, gave the aircraft its distinctive, ungainly appearance, and it was one reason for the aircraft’s slowness. The SBD’s armament was modest: two .50-calibre machine guns in the nose, firing forward, and one or two .30-calibre machine guns in the rear cockpit, fired by the gunner. The aircraft’s bomb load was a single 1,000-pound bomb under the fuselage, carried on a swinging crutch that swung the bomb clear of the propeller during the dive, plus two 100-pound bombs under the wings.

Toughness and the Rear Gunner

The SBD was known for its toughness, and for the skill of its rear gunners. The aircraft could absorb a great deal of battle damage — from anti-aircraft fire, from fighters and from the stresses of the dive — and still bring its crew home, and many SBDs returned to their carriers with holes in their wings, with damaged engines and with wounded crewmen. The rear gunner, who sat in the rear cockpit with a pair of .30-calibre machine guns, was the aircraft’s only defence against fighters attacking from behind, and the gunners shot down many Japanese fighters, above all the Zero, which was faster than the SBD but which was lightly built and vulnerable to the gunner’s fire. The SBD’s toughness and its gunners’ skill are the reasons why the aircraft’s losses, although heavy, were lower than those of the torpedo bombers that flew with it, and why the SBD’s crews trusted their aircraft with their lives.

5. Variants

The Main Production Versions

Variant	Years	Key features	Production
SBD-1	1940	First production version; Marine Corps; 1,000 hp engine	57
SBD-2	1940–1941	Navy version; more fuel; armour	87
SBD-3	1941–1942	Self-sealing fuel tanks; armour; 1,000 hp; Midway version	584
SBD-4	1942	Improved electrical system; 24-volt system	780
SBD-5	1942–1944	Most-produced version; 1,200 hp engine; more ammunition	2,965
SBD-6	1944	1,350 hp engine; improved fuel system	451
A-24 Banshee	1940–1943	Army Air Forces version of the SBD; used in the Philippines and New Guinea	About 1,000 (A-24, A-24A, A-24B)

The SBD was produced in a series of versions, each of which was an improvement on the one before. The SBD-1 and SBD-2 were the first production versions, and they were used in the early fighting in the Pacific. The SBD-3, which was the version that fought at Midway, had self-sealing fuel tanks and armour, which the earlier versions lacked, and it was the first SBD that could survive the battle damage of a dive-bombing attack. The SBD-4 had an improved electrical system, and the SBD-5, which was the most-produced version, had a more powerful 1,200-horsepower engine and more ammunition for its machine guns. The SBD-6, the final version, had a 1,350-horsepower engine, but it was produced in small numbers, because the Navy had already decided to replace the SBD with the SB2C Helldiver. The Army Air Forces’ version, the A-24 Banshee, was almost identical to the SBD, but it was used by the Army, not the Navy, and it fought in the Philippines and in New Guinea.

The A-24 Banshee / A-24 Banshee

The A-24 Banshee was the Army Air Forces’ version of the SBD, and it is often forgotten, because the SBD’s fame belongs to the Navy and the Marine Corps. The A-24 was almost identical to the SBD-3, except that it had no arrester hook and no folding wings, because it was not designed to operate from a carrier, and it was used by the Army in the Philippines, where the A-24s of the 27th Bombardment Group were destroyed on the ground in the Japanese attack of December 1941, and in New Guinea, where the A-24s of the Fifth Air Force bombed Japanese positions. The A-24’s service was less successful than the SBD’s, because the Army did not have the Navy’s dive-bombing doctrine and because the A-24 was used for level bombing, for which it was not designed. The A-24 was withdrawn from service in 1943, and the Army’s dive-bombing role was taken over by the A-36 Apache, a version of the P-51 Mustang. The A-24’s story is a reminder that an aircraft’s success depends as much on its doctrine as on its design.

6. Operational History

The Coral Sea, May 1942

The SBD’s first great battle was the Battle of the Coral Sea, in May 1942, the first naval battle in history in which the opposing fleets never saw each other and in which all the fighting was done by aircraft. On 7 May 1942, SBDs from the American carriers Lexington and Yorktown sank the Japanese light carrier Shoho, and on 8 May they attacked the Japanese fleet carriers Shokaku and Zuikaku, damaging Shokaku and forcing both carriers to withdraw. The Coral Sea was a tactical victory for Japan — the Americans lost the carrier Lexington — but it was a strategic victory for the United States, because the Japanese invasion of Port Moresby was stopped and because Shokaku and Zuikaku were too damaged to take part in the Battle of Midway a month later. The SBD’s part in the Coral Sea was the first demonstration of its power as a dive bomber, and it set the stage for Midway.

Midway, 4 June 1942

The Battle of Midway, on 4 June 1942, was the most decisive naval battle of the Pacific War, and it was the SBD’s finest hour. In a single morning, the SBDs of the Enterprise, Yorktown and Hornet sank three Japanese fleet carriers, and in the afternoon they sank the fourth, and the Japanese Navy lost the core of its carrier force. The two sections below describe the morning attack, in which the SBDs arrived at the moment when the Japanese carriers were most vulnerable, and the reasons why Midway mattered — why the loss of four carriers and of their trained aircrews broke Japanese naval air power for the rest of the war.

The morning of 4 June 1942 began badly for the Americans: their torpedo bombers were destroyed, their fighters were scattered, and the Japanese carriers seemed invulnerable. But the torpedo bombers’ sacrifice had drawn the Japanese fighters down to sea level, and when the SBDs arrived, the Japanese carriers were unprotected, their decks crowded with aircraft being fuelled and armed. The SBDs’ attack, which lasted only a few minutes, decided the battle and the war.

The Morning Attack

The Battle of Midway, on 4 June 1942, was the SBD’s finest hour, and one of the most decisive battles in naval history. The Japanese fleet, under Admiral Isoroku Yamamoto, had four fleet carriers — Akagi, Kaga, Soryu and Hiryu — and the American fleet, under Admirals Chester Nimitz, Frank Jack Fletcher and Raymond Spruance, had three — Enterprise, Hornet and Yorktown. In the morning of 4 June, the Japanese carriers launched their aircraft against Midway Island, and the American carriers launched their aircraft against the Japanese fleet. The American torpedo bombers, the TBD Devastators, attacked first, and they were almost wiped out by the Japanese fighters, but their sacrifice drew the Japanese fighters down to sea level, and when the SBDs arrived, at about 10:20, the Japanese carriers were unprotected. The SBDs of Enterprise and Yorktown dived on the Akagi, the Kaga and the Soryu, and within a few minutes all three carriers were burning. The Hiryu, which had not been attacked, launched her aircraft against the Yorktown, which was badly damaged, but in the afternoon the SBDs of Enterprise and Hornet found the Hiryu and sank her as well. By the end of the day, all four Japanese carriers were sunk, and the Japanese Navy had lost the core of its carrier force.

Why Midway Mattered

Midway was the turning point of the Pacific War, and the SBD was the aircraft that won it. The Japanese Navy never recovered from the loss of its four carriers and of the trained aircrews who died with them, and the United States, which could build new carriers and train new pilots, took the initiative in the Pacific and never gave it up. The SBD’s part in the victory was decisive: the dive bombers sank the carriers, and they did so in a few minutes, with a precision that no other weapon could have achieved. The battle also showed the importance of the dive bomber: the torpedo bombers, which had attacked first, had been destroyed, but the dive bombers, which had arrived at the right moment, had won the battle. The SBD’s crews, above all the pilots of Bombing Squadron 6 (VB-6) and Scouting Squadron 6 (VS-6) from the Enterprise, and of Bombing Squadron 3 (VB-3) from the Yorktown, became heroes, and their leader, Lieutenant Commander Wade McClusky, who had found the Japanese fleet by following a Japanese destroyer, is remembered as one of the great naval aviators of the war.

Guadalcanal and the Later War

After Midway, the SBD served at Guadalcanal, where the Marine Corps’ SBDs, flying from Henderson Field, attacked Japanese shipping in the Slot and supported the Marines on the island. The SBD’s service at Guadalcanal was long and hard: the aircraft flew daily missions against Japanese ships and positions, and they suffered heavy losses to Japanese fighters and to anti-aircraft fire, but they sank many Japanese ships and they helped to win the campaign. The SBD also served in the later battles of the Pacific — in the Philippines, at Leyte Gulf and on Okinawa — but by 1944 it was being replaced by the SB2C Helldiver, which was faster and could carry a heavier bomb load. The SBD’s last combat missions were flown in 1944, and the aircraft was withdrawn from front-line service in 1945, although it remained in service as a trainer and as a target tug for several more years. The SBD’s service had lasted from 1940 to 1945, and it had fought in every major battle of the Pacific War.

7. Performance and Specifications

Specifications

Specification	SBD-5
Engine	Wright R-1820-60 Cyclone, 1,200 hp
Maximum speed	About 410 km/h
Cruising speed	About 300 km/h
Range	About 1,795 km
Service ceiling	About 7,800 m
Rate of climb	About 8 m/s (estimated)
Empty weight	About 2,905 kg
Maximum take-off weight	About 4,850 kg
Armament	2 × 12.7 mm forward; 1–2 × 7.62 mm rear
Bomb load	1 × 1,000 lb (450 kg) + 2 × 100 lb
Crew	2
Number built	5,936 (all versions)

The table shows the SBD-5, the most-produced version, and its performance was modest by the standards of the fighters of the period: its maximum speed of about 410 km/h was slower than that of the Japanese Zero (about 540 km/h) and of the American Wildcat (about 510 km/h), and its range of about 1,795 km was its greatest strength, because it allowed the SBD to search for the enemy fleet and to attack it from a great distance. The SBD’s bomb load of a single 1,000-pound bomb was small, but it was enough to sink a carrier if it hit the flight deck, where the aircraft were fuelled and armed, and the SBD’s accuracy — the product of its dive brakes, its telescopic sight and its pilots’ skill — meant that its bombs rarely missed. The SBD’s performance was not impressive on paper, but in combat it was deadly, and its record of ships sunk is unmatched by any other dive bomber of the war.

Comparison with Other Dive Bombers

Compared with the other dive bombers of the war, the SBD was slower but more accurate and more reliable. The Japanese Aichi D3A “Val”, which was the standard Japanese dive bomber, was faster (about 430 km/h) and could carry a similar bomb load, but it was lightly built and vulnerable to fire, and it was withdrawn from service earlier. The German Junkers Ju 87 Stuka, which was the most famous dive bomber of the war, was slower (about 390 km/h) and could carry a heavier bomb load, but it was vulnerable to fighters and it was withdrawn from the Eastern Front in 1943. The American SB2C Helldiver, which replaced the SBD, was faster (about 470 km/h) and could carry a heavier bomb load, but it was difficult to fly and unpopular with its crews, and it never achieved the SBD’s record. The SBD’s balance of accuracy, reliability and toughness made it the most successful dive bomber of the war, in the judgement of many historians, and its victory at Midway is the proof.

8. Operators

The United States Navy and Marine Corps

The SBD was used principally by the United States Navy and the United States Marine Corps, and it served with the carrier air groups of the Enterprise, Yorktown, Hornet, Lexington, Saratoga and Wasp, and with the Marine squadrons at Midway, at Guadalcanal and in the Philippines. The Navy’s SBDs were the aircraft that won Midway, and the Marine Corps’ SBDs were the aircraft that held Guadalcanal, and the two services’ SBDs are remembered together as the dive bombers of the Pacific War. The SBD also served with the United States Army Air Forces, as the A-24 Banshee, but the Army’s version was less successful, and it was withdrawn from service in 1943. The SBD remained in Navy and Marine Corps service until 1945, when it was replaced by the SB2C Helldiver, and it is the Navy and Marine Corps SBD that is best remembered today. The SBD’s service with the Navy and the Marine Corps is one reason why it is so well known: the aircraft was flown by the men who won Midway and who held Guadalcanal, and its story is told in the museums and in the histories of both services.

Other Users

The SBD was supplied to America’s allies in small numbers, and it was used by the Royal Navy’s Fleet Air Arm, which received a small number of SBDs and used them for trials, and by the Free French, who received a small number and used them in the Pacific. The SBD was also used by New Zealand, which received a small number of SBDs and used them in the Pacific, and by Mexico, which received a small number and used them for patrol duties. The SBD’s foreign service was small, because the aircraft was needed by the American Navy and Marine Corps, and because the SB2C Helldiver was already in production by the time the Allies asked for dive bombers. The SBD’s story is therefore an American story, and it is told in America as the story of the aircraft that won Midway. The SBD’s foreign service was small, but it showed that the aircraft was valued by every navy that flew it, and the Royal Navy’s trials of the SBD influenced the design of the British dive bombers that followed it.

9. Legacy and Influence

The Aircraft That Won Midway

The SBD’s legacy is Midway, and Midway is one of the most decisive battles in history. The SBD’s sinking of four Japanese carriers in a single day changed the course of the Pacific War, and it is the reason why the SBD is remembered as one of the great aircraft of the war. The SBD’s victory at Midway is studied by naval officers around the world, and it is the classic example of the power of the dive bomber and of the importance of timing, of courage and of luck in naval warfare. The SBD’s pilots, above all Wade McClusky, Richard Best and Norman Kleiss, are remembered as heroes, and their names are known to every student of the Pacific War. The SBD’s legacy is therefore not only a technical legacy but a human one: the legacy of the men who flew a slow, vulnerable aircraft into the teeth of the Japanese defences and who sank the carriers that had attacked Pearl Harbor.

The End of the Dive Bomber

The SBD’s retirement in 1945 marked the end of the dive bomber as a distinct type of aircraft. The dive bomber had been the most accurate way to attack a ship in the 1930s and early 1940s, but by the end of the war it was being replaced by the fighter-bomber, which could dive-bomb and also fight as a fighter, and by the guided missile, which could hit a ship from a great distance without diving at all. The SBD’s successor, the SB2C Helldiver, was the last American dive bomber, and it was withdrawn from service in the 1950s. The dive bomber’s story is therefore the story of a weapon that was supreme for a short time — from the mid-1930s to the mid-1940s — and that was then overtaken by technology. The SBD is the dive bomber that is best remembered, because it won the most important battle that a dive bomber ever won, and its name is synonymous with the dive bomber itself.

10. Surviving Examples

Museums

Only a small number of SBDs survive today, because most were scrapped after the war, but the survivors include some of the most famous aircraft in American museums. The best-known is the SBD-3 at the National Naval Aviation Museum in Pensacola, Florida, which is displayed as one of the aircraft that fought at Midway, and the SBD-5 at the Smithsonian National Air and Space Museum in Washington, D.C. Other SBDs are held at the Imperial War Museum at Duxford in Britain, at the Pacific Aviation Museum in Honolulu, Hawaii, and at the museums of New Zealand and Australia. The SBD’s survival rate is low for an aircraft of which almost 6,000 were built, because the aircraft was worn out by the war and because it was replaced by the Helldiver, but the survivors are among the most treasured aircraft in the museums that hold them, because of their association with Midway.

Flying Warbirds

A small number of SBDs still fly, and they are among the rarest warbirds at airshows. The Commemorative Air Force operates an SBD-5, which flies at airshows in the United States, and other SBDs are flown by private owners and by museums. The flying SBDs are often displayed alongside the F6F Hellcat and the F4U Corsair, the fighters that fought with them in the Pacific, and they are a reminder of the dive bomber’s part in the war. The SBD’s rarity makes it a prized exhibit: for many visitors, the sight of an SBD in the air, with its fixed landing gear and its perforated dive brakes, is a glimpse of a type of aircraft that no longer exists, and of a battle — Midway — that changed the world. For most people, the easiest way to see an SBD is at the National Naval Aviation Museum in Pensacola or the Smithsonian in Washington, D.C.

Frequently Asked Questions

What is the SBD Dauntless?
The SBD Dauntless was an American carrier-based dive bomber of the Second World War, designed by Douglas Aircraft and nicknamed “Slow But Deadly”. About 5,936 were built.

What did the SBD do at Midway?
On 4 June 1942, SBDs from the carriers Enterprise, Yorktown and Hornet sank all four Japanese fleet carriers — Akagi, Kaga, Soryu and Hiryu — in a few hours, winning the Battle of Midway and changing the course of the Pacific War.

Why was the SBD called “Slow But Deadly”?
Because it was slow — its top speed was only about 410 km/h — but its dive-bombing was deadly accurate, and it sank more ships than any other dive bomber of the war.

How many SBDs were built?
5,936 SBDs were built between 1940 and 1944. The most-produced version was the SBD-5, with 2,965 built.

What replaced the SBD?
The Curtiss SB2C Helldiver, which was faster and could carry a heavier bomb load, but which was difficult to fly and never achieved the SBD’s record.

Where can I see an SBD today?
At the National Naval Aviation Museum in Pensacola, Florida, and the Smithsonian National Air and Space Museum in Washington, D.C., among other museums. A small number still fly at airshows.

Sources

1. Wikipedia, “Douglas SBD Dauntless” — production of 5,936, specifications, Midway.
2. National Naval Aviation Museum, “SBD Dauntless” — the SBD-3 on display at Pensacola and the Battle of Midway.
3. Smithsonian National Air and Space Museum, “Douglas SBD-6 Dauntless” — specifications and surviving aircraft.
4. Barrett Tillman, The Dauntless Dive Bomber of World War II (Naval Institute Press, 1976) — development, Midway and operational history.
5. Jonathan Parshall and Anthony Tully, Shattered Sword: The Untold Story of the Battle of Midway (Potomac Books, 2005) — Midway and the sinking of the four carriers.
6. U.S. Naval History and Heritage Command, “Battle of Midway” — the battle and the SBD’s part in it.