A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. This type of aircraft was most widely used before and during World War II; its use fell into decline shortly afterwards.

Technique

Diving nearly vertically at the target, in the same direction the bombs will take, the aircraft will release the bombs very close to the target at high speed. This allows a dive bomber to accurately place bombs on smaller and/or moving targets with relative ease. Additionally, no complicated precision bomb sight is needed for targeting.

Dive bombers were widely used to attack high value targets such as ships and bridges. This tactic also gave the advantage of attacking ships at a weak spot; armour was typically heaviest near the waterline and thin or non-existent on the deck. In addition, dive bombing allowed relatively small aircraft carrying limited bomb loads to inflict disproportionately heavy damage.

On the negative side, optimizing an aircraft for near-vertical dives came at the expense of performance. In addition, a dive bomber was highly vulnerable to ground fire as it dived towards its target. Dive brakes were employed on many designs. These created drag which slowed the aircraft somewhat in order to increase accuracy and to prevent speeds which could damage the structures of the plane. These were almost exclusive to dive bombers, though the air brakes fitted to modern aircraft are often of a similar design.

History

World War I and inter-war period

The first recorded use of dive bombing was an ad-hoc solution by British Royal Flying Corps pilots during World War I. In 1917 and 1918, they practised the technique at the Orford Ness Bombing Range, but the aircraft of the day were generally too frail to be able to withstand the acceleration generated when pulling out of the dive after releasing the bomb load.

The first combat dive bombing attack took place in early 1919 when United States Marine Corps pilot Lt. L. H. Sanderson mounted a carbine barrel in front of the windshield of his Curtiss JN-4 (an unarmed training craft) as an improvised bomb sight that was lined up with the long axis of his plane, loaded a bomb in a canvas bag that was attached to the plane's belly, and launched a single-handed raid in support of a USMC unit that had been trapped by Haitian Cacos rebels. Sanderson's "Jenny" almost disintegrated when he pulled it into a steep climb after releasing his ordnance, but the bomb had hit its target precisely and the raids were repeated. During 1920 Sanderson familiarized aviators of USMC units at the Atlantic coast with the dive bombing technique. Dive bombing was also used during the United States occupation of Nicaragua.

As planes grew in strength and load capability, the technique became more valuable. By the early 1930s, the technique was clearly favoured in tactical doctrine, notably against targets that would otherwise be too small to hit with level bombers. While the United States Army Air Corps concentrated on mass attacks by very large bombers, the Navy ordered the first custom dive bomber aircraft, the Curtiss F8C Hell-Diver biplane (not to be confused with the later SB2C Helldiver).

Generally, dive bombing was a technique preferred by naval air forces. Because navies operated from aircraft carriers or small airfields, they had "smaller numbers of aircraft available for any one attack, and each aircraft was often unable to carry more than a few bombs per plane." They also were frequently required to attack smaller-sized or moving targets, such as ships. The combination of a small bomb load and the need for accuracy made dive bombing techniques a requirement for naval airplanes.

World War II

The only major force not to deploy a dedicated dive bomber were the inventors of the tactic, the British. The Royal Navy attempted to introduce their own on several occasions, but were never able to do so due to various reasons, not the least of which was political interference by the RAF. They only produced hybrid aircraft: the Blackburn Skua, a dive bomber/fighter that was used for a short time and in small numbers, and the Fairey Barracuda, a dive bomber/torpedo bomber.

European theater

In the early 1930s, Ernst Udet visited the U.S. and was able to purchase four F8Cs and ship them to Germany, where they caused a minor revolution. The dive bombing technique would allow a much smaller Luftwaffe to operate effectively in the tactical role. Soon they had sent out contracts for their own dive bomber designs, resulting in the gull-winged Junkers Ju 87 Stuka (a contraction of Sturzkampfflugzeug, literally "dive-combat-air-plane").

When it was introduced in 1936, the Stuka was the most advanced dive bomber in the world. Using it as "aerial artillery" solved a major problem in the concept of Blitzkrieg—how to attack dug-in defensive positions. Normally this would require slow-moving artillery to be used, making the fast moving armoured forces wait for it to catch up.

This was proven to great effect during the invasion of Poland and the Low Countries. In one particular example, the British Expeditionary Force set up strong defensive positions on the west bank of the Oise River just in front of the rapidly advancing German armour. Attacks by Stukas quickly broke the defence, and combat engineers were able to force a crossing long before the artillery arrived. Another important example was the massive aerial attacks in 13 May 1940 against strong French defence positions at Sedan in the Battle of France, which allowed the German forces a fast and (for the Allies) unexpected breakthrough through the French lines, eventually leading to the German advance to the Channel and the cutting off of large parts of the Allied army.

Despite its success in the French campaign, the Stuka soon showed its weaknesses in the Battle of Britain where great numbers of Stukas were lost due to its inappropriate use as a tactical bomber.

The Ju 87 Stuka was the only widely used dedicated tactical dive bomber to be deployed against both naval and land targets, particularly with regard to the latter in the anti-armor role. Stukas also had 7.92mm machine guns or 20mm cannons mounted in the wings, with some modified to have 37mm cannons mounted below the wings for anti-tank work. With the loss of Luftwaffe air superiority however they became vulnerable to the Red Army Air Force fighters, and from 1943 had begun conversion to the more conventional cannon attack tactics.

Pacific theater

Both the Imperial Japanese Navy (IJN) and the U.S. Navy invested considerable effort on dive bombers. Japan started the war with one of the best designs, the Imperial Navy's carrier-borne Aichi D3A (Val). But as the war progressed, the design quickly became outdated, in part due to its fixed main landing gear (a shortcoming shared by their ally's Stuka Ju87). Later, when the IJN was no longer on the offensive, the more advanced Yokosuka D4Y Suisei entered service. By then, Japan's industry was straining under the relentless submarine warfare campaign being waged by the US Navy, which interdicted the raw materials needed by Japanese factories.

The U.S. fielded the Douglas SBD Dauntless, which was similar to the D3A in performance. The Dauntless was replaced with the faster, but more complex Curtiss SB2C Helldiver. As was usual with US war industry during WWII, both airplanes were built in large numbers.

The most famous example of successful naval dive-bombing attacks took place in the decisive Battle of Midway in June 1942 when American Dauntlesses scored fatal hits on three separate first-line Japanese aircraft carriers within a six minute timespan. Within hours the Imperial Japanese Navy had lost several years worth of combat experienced naval airmen, which until the end of the war in 1945 would never be replaced.

For the IJN, their dive bombing moment of success, albeit not as devastating as the American victory at Midway, was during their Indian Ocean Raids in April 1942. During that foray into the Indian Ocean, the Japanese carriers launched strikes against the British navy's battle squadrons stationed near Ceylon and India, and Vals succeeded in sinking the Royal Navy heavy cruisers HMS Cornwall and HMS Dorsetshire, and the aircraft carrier HMS Hermes along with her escort destroyer HMS Vampire.

Decline

After the war, the dive bomber class quickly disappeared. Anti-aircraft warfare had improved as had the speed and effectiveness of fighter aircraft against the vulnerable, slow-flying dive bombers. At the same time the quality of various computing bomb sights allowed for much better accuracy from smaller dive angles, and the sights could be fitted to almost any plane, especially fighter aircraft, much improving the effectiveness of ground-attack aircraft. Although the aircraft could still "dive" on their targets to some degree, they were no longer optimized for steep diving attacks at the expense of other capabilities as the dive bombers of old. As these same aircraft were capable of many other missions as well, they were no longer considered to be dive bombers.

After pioneering efforts in World War II by both the Nazi-era Luftwaffe with the Fritz X, and the USAAF with the Azon controlled-trajectory bombs, today's smart bombs are used for precision bombing. Bombs can be dropped many miles from the target at high altitudes, placing the aircraft at little risk. The bomb then guides itself onto the target through a number of means, which can include laser designation, onboard GPS, radar, infrared, television guidance, and inertial wind-correction. Bomb sights continue to supply several "toss bombing" modes, a sort of reverse dive bombing where an aircraft releases its bomb while steeply pulling up from low level. Shallow, 45° or less dive bombing attacks are still used to deliver gravity bombs when they are employed.

References

Brown, David. Warship Losses of World War Two. Arms and Armour, London, Great Britain, 1990. ISBN 0-85368-802-8.

External links

"Dive Bombing at Target Assures Accuracy" April 1933, ''Popular Mechanics - early article on dive bombing for general public

, April 1942, Popular Science"> "Diving Artillery" , April 1942, Popular Science good article on the basics of dive bombing with illustration and rare photos

Tail Brake on Do-217E Controls Its Diving Speed, November 1942, Popular Science

Category:Bomber aircraft

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