Dive bomber
This article's lead section may be too short to adequately summarize the key points. (November 2016) |
A dive bomber is a
After World War II, the rise of precision-guided munitions and improved anti-aircraft defences—both fixed gunnery positions and fighter interception—led to a fundamental change in dive bombing. New weapons, such as rockets, allowed for better accuracy from smaller dive angles and from greater distances. They could be fitted to almost any aircraft, including fighters, improving their effectiveness without the inherent vulnerabilities of dive bombers, which needed air superiority to operate effectively.
Method
A dive bomber dives at a steep angle, normally between 45 and 60 degrees or even up to a near vertical dive of 80 degrees with the Junkers Ju 87, and thus requires an abrupt pull-up after dropping its bombs. This puts great strains on both the pilot and aircraft. It demands an aircraft of strong construction, with some means to slow its dive. This limited the class to light bomber designs with ordnance loads in the range of 1,000 lb (450 kg) although there were larger examples. The most famous examples are the Junkers Ju 87 Stuka, which was widely used during the opening stages of World War II, the Aichi D3A "Val" dive bomber, which sank more Allied warships during the war than any other Axis aircraft,[2][3][4] and the Douglas SBD Dauntless, which sank more Japanese shipping than any other allied aircraft type.[5] The SBD Dauntless helped win the Battle of Midway, was instrumental in the victory at the Battle of the Coral Sea, and fought in every US battle involving carrier aircraft.[6][7]
An alternative technique, glide-bombing, allowed the use of heavier aircraft, which faced far greater difficulties in recovering from near-vertical approaches, though it required greater use of sophisticated bombsights and aiming techniques, by a specialised member of aircrews, namely a
Dive bombing was most widely used before and during World War II; its use declined during the war, when its vulnerability to enemy fighters became apparent. In the post-war era, this role was replaced with a combination of improved and automated
Accuracy
When released from an aircraft, a bomb carries with it the aircraft's trajectory. In the case of a bomber flying horizontally, the bomb will initially only be travelling forward. This forward motion is opposed by the
The distance that the bomb moves forward while it falls is known as its range. If the range for a given set of conditions is calculated, simple trigonometry can be used to find the angle between the aircraft and the target. By setting the bombsight to this "range angle", the aircraft can time the drop of its bombs at the instant when the target is lined up in the sight. This was only effective for "area bombing", however, since the path of the bomb is only roughly estimated. Large formations could drop bombs on an area hoping to hit a specific target, but there was no guarantee of success, and huge areas around the target would also be hit. The advantage to this approach, however, was that it is easy to build such an aircraft and fly it at high altitude, keeping it out of range of ground-based defences.
The horizontal bomber was thus ill-suited for tactical bombing, particularly in close support. Attempts at using high-altitude bombing in near-proximity to troops often ended in tragedy, with bombs both hitting their targets and friendly troops indiscriminately. In attacking shipping, the problems of inaccuracy were amplified by the fact that the target could be moving, and could change its direction between the time that the bombs were released and the time that they arrived. Successful strikes on marine vessels by horizontal bombers were extremely rare. An example of this problem can be seen in the attempts to attack the Japanese carriers using B-17s at altitude in the Battle of Midway, with no hits scored. The German battleship Tirpitz was subjected to countless attacks, many while in dock and immobile, but was not sunk until the British brought in enormous 12,000 lb (5,400 kg) Tallboy bombs to ensure that even a near miss would be effective.
An aircraft diving vertically minimises its horizontal velocity component. When the bomb is dropped, the force of gravity simply increases its speed along its nearly vertical trajectory. The bomb travels a virtually straight line between release and impact, eliminating the need for complex calculations. The aircraft simply aims at the target and releases its bombs. The primary source of error is the effect of wind on the bomb's flight path after release. As bombs are streamlined and heavy, wind has only a slight effect on them and the bomb is likely to fall within its lethal radius of the target.
Bomb sighting becomes trivial, requiring only a straight line of sight to the target. This was simplified as the aircraft was pointed directly at the target, making sighting over the nose much easier. Differences in the path of different bombs due to differing ballistics can be corrected by selecting a standardised bombing altitude and then adjusting the dive angle slightly for each case. As the bomber dives, the aim could be continually adjusted. In contrast, when a horizontal bomber veers offline while approaching the bomb release point, turning to the angle that would correct this also changes the speed of the aircraft over the ground (when there is a wind) and thereby changes the range as well.
In the 1930s and early 1940s, dive bombing was the best method for attacking high-value compact targets, like
The
A dive bomber was vulnerable to low-level ground fire as it dived towards its target, since it was often headed in a straight line directly towards the defenders. At higher levels, this was less of a problem, as larger AA (anti-aircraft) shells were fused to explode at specific altitudes, which is impossible to determine while the plane is diving. In addition, most higher-altitude gunners and gunnery systems were designed to calculate the lateral movement of a target; while diving, the target appears almost stationary. Also, many AA mounts lacked the ability to fire directly up, so dive bombers were almost never exposed to fire from directly ahead.
Origins
It is difficult to establish how dive bombing originated. During World War I, the Royal Flying Corps (RFC) found its biplane two-seat bombers insufficiently accurate in operations on the Western Front. Commanders urged pilots to dive from their cruising altitude to under 500 ft (150 m) to have a better chance of hitting small targets, such as gun emplacements and trenches.[11] As this exposed the aircraft and crew to destructive ground fire in their unprotected open cockpits, few followed this order. Some recorded altitude at the top and bottom of their dive in log books and in squadron records, but not the steepness of the dive. It was certainly not near-vertical, as these early aircraft could not withstand the stresses of a sustained vertical dive.[12]
The Royal Naval Air Service was bombing the Zeppelin sheds in Germany and in occupied Belgium and found it worthwhile to dive onto these sheds to ensure a hit, despite the increased casualties from ground fire. Again, the angle of dive in these attacks was not recorded.[11]
Beginning on 18 June 1918, the
Heavy casualties resulting from air-to-ground attack on trenches set the minds of senior officers in the newly formed RAF against dive bombing. So not until 1934 did the Air Ministry issue specifications for both land-based and aircraft carrier-based dive bombers. The RAF cancelled its requirement and relegated the Hawker Henley dive bomber to other roles, while the Fleet Air Arm's Blackburn Skua was expected to do double duty: as a fighter when out of reach of land-based fighter support, and as a dive bomber. It had dive brakes that doubled as flaps for carrier landings.[14] The Hawker Henley had a top speed only 50 mph (80 km/h) slower than the Hawker Hurricane fighter from which it was derived. The American and Japanese navies and the Luftwaffe chose vertical dive bombers whose low speed had dire consequences when they encountered modern fighters.[12]
World War I
The Royal Naval Air Service developed dive bombing as a tactic against Zeppelin hangars and formed and trained a squadron at Manchester for this task. On 8 October 1914, a Sopwith Tabloid with two 50 lb (23 kg) bombs attacked a hangar at Düsseldorf after a dive to 600 ft (180 m). On 14 November 1914, four Avro 504s attacked the Zeppelin factory at Friedrichshafen on Lake Constance, diving from 1,200 ft (370 m) to 500 ft (150 m) to ensure hits. As Zeppelins were tethered close to stores of hydrogen, results were often spectacular.[11]
The first use of dive bombing by the RFC, which had been urging its pilots to drop bombs at heights below 500 ft (150 m) in order to hit within 150 ft (46 m) of the target since February 1915, was later that year. On 27 November 1915, Lieutenant
The Royal Flying Corps developed
Second Lieutenant
Interwar era
The Royal Flying Corps was initially impressed with the potential of the dive bomber, but was aware of its suicidal nature. It ran a series of tests at the Armament Experimental station at
Colonel, later general,
Opposite conclusions were drawn by the RAF and USAS, from two very different tests regarding the usefulness of dive bombers, with the RAF concluding that the cost in pilots was too high to justify the results and the USAS considering it as a potent anti-ship weapon. Both naval staffs opposed the view taken by the respective airmen.[21]
In 1919,
As aircraft grew more powerful, dive bombing became a favoured tactic, particularly against small targets such as ships.
The
Navies increasingly operated carriers, which had a limited number of aircraft available for attack, each with only a small bomb load. Targets were often likely to be small or fast-moving and the need for accuracy made dive bombers essential.[21]
Dive bombing would allow a low-cost Luftwaffe to operate effectively in the tactical role. Against small targets, a single-engine dive bomber could achieve four times the accuracy at one tenth of the cost of a four-engine heavy bomber, such as the projected Ural bomber,[25] and it could reach the battlefield well ahead of field artillery. Soon the Luftwaffe issued a contract for its own dive bomber design, resulting in the Junkers K 47, which, following extensive trials, would in turn result in the Junkers Ju 87 Stuka (a contraction of Sturzkampfflugzeug, literally 'diving combat airplane').[24]
Several early Junkers Ju 87 dive bombers, which first flew on 13 September 1935, were shipped secretly from Germany to Spain to assist General
Some 23
As the Royal Navy again took control of the
The British Air Ministry issued Specification 4/34 in 1934 for a ground attack aircraft with dive bombing capability. The Hawker Henley was a two-seat version of the Battle of Britain-winning Hawker Hurricane. It was fast, at almost 300 mph (480 km/h) at sea level and 450 mph (720 km/h) in a dive, but development was delayed when Hurricane development took priority. Just 200 were built and it was relegated to target towing.[33] The RAF ordered the US-built Vultee A-31 Vengeance in 1943, but it, too, was similarly relegated to target towing after a brief operation period in secondary theatres.[citation needed]
The Curtiss SBC Helldiver was a biplane dive bomber that had been taken aboard the USS Yorktown (CV-5) in 1934, but it was slow, at 234 mph (377 km/h). Fifty ex-US Navy examples were flown to Halifax, Nova Scotia, by Curtiss pilots and embarked on the French aircraft carrier Béarn in a belated attempt to help France, which surrendered while they were mid-Atlantic. Five airframes left behind in Halifax later reached the RAF, which quickly relegated them to the status of ground instructional airframes for the training of mechanics.[34]
The Japanese introduced the Aichi D3A Val monoplane as a successor to the biplane Aichi D1A in 1940, with trials aboard the carriers Kaga and Akagi. It was to prove a potent weapon against surface ships.[28]
Only the
The RAF had chosen the single-engined
European theatre
On 10 April 1940, 16 British Royal Navy
The
On 12/13 May 1940, Stukas flew 300 sorties against strong French defensive positions at the Battle of Sedan. This enabled German forces to make a fast and unexpected breakthrough of the French lines, eventually leading to the German advance to the Channel and the cutting off of much of the Allied army.[26]
The skies over Sedan also showed the Stuka's weakness when met with fighter opposition; six French
The Stuka had
The most successful dive-bomber pilot, Hans-Ulrich Rudel, made 2,530 sorties. He contributed to the sinking of the Soviet battleship Marat at Kronstadt on 23 September 1941 using 1,000 kg (2,200 lb) bombs. Later, flying a tank-buster Stuka with 20mm cannon, he claimed over 100 Soviet tanks destroyed, mostly at the Battle of Kursk in July 1943. The Ju 87G Kanonenvogel, equipped with two 37mm BK 3,7 anti-tank guns, as suggested by Rudel, proved to be a lethal weapon in skilled hands. In the Soviet counter-offensive, Operation Kutuzov (July to August 1943), which concluded Kursk, the Luftwaffe claimed 35 tanks destroyed in a single day.[38] Rudel co-wrote a post-war book about his experiences and consulted with the US Air Force.[39]
When Italy joined the war (10 June 1940) on the Axis side, the Regia Aeronautica shipped Breda Ba.65s to North Africa for use against the British but they also proved vulnerable. By February 1941 British fighters had shot down most of the Italian planes.[40] In Morocco on 11 November 1942, American Curtiss P-40 Warhawks shot down 15 Ju 87Ds in one encounter.[41]
The
The Royal Navy's Fairey Swordfish and Fairey Albacore torpedo-dive bombers and Blackburn Skua fighter-bombers were replaced by Fairey Barracuda torpedo-dive bombers, which made repeated diving attacks on the German battleship Tirpitz which lay protected by torpedo nets in a Norwegian fjord during 1944. On 3 April 1944, in Operation Tungsten, 42 aircraft flying from the carriers HMS Victorious and HMS Furious scored 14 hits with 500 lb (230 kg) and 1,600 lb (730 kg) bombs and put the battleship out of action for over two months.[44]
The Soviet Union Armed Forces deployed the Arkhangelsky Ar-2 from 1940 to 1944 and the Petlyakov Pe-2 from 1941 to 1954.
Pacific theatre
The
Both the
The main American dive bomber, the
On 5 April 1942, the heavy cruisers
At the
Later on 4 June, Yorktown and Enterprise dive bombers inflicted fatal damage on the fourth Japanese carrier
The United States Army Air Forces took a version of the Dauntless with a different tailwheel tire and no arrester hook as the
The Japanese
Henceforward attacks were mostly confined to kamikaze.[52] The Japanese were now on the defensive. Japan's industrial output dropped from a peak in 1942, while that of the US increased by a quarter in two years from 1942 to 1944. Japanese wartime production of bombers of all types was just 16% of the US output.
Decline
When the RAF were attempting to stop the
On 23 May 1943, a Fairey Swordfish destroyed U-752 in the Atlantic, and five days later, a Lockheed Hudson of RAF Coastal Command sank U-755 in the Mediterranean, using specialised rockets fitted with iron spikes which were fired at a shallow angle into the sea. Once under water, they curved upwards and punctured the pressure hull below the waterline, disabling or sinking the submarine.[55]
By late 1944, the RAF was able to hit stationary targets with greater accuracy from greater heights inflicting far more damage with less risk. On 12 November 1944, two 5-long-ton (5.1 t)
Pilots in the Pacific later developed a technique of skip bombing which required flying at low level and dropping a spherically nosed conventional bomb onto the sea, at a shallow angle, which then bounced back into the air.
Although new aircraft could still dive towards their targets, they were no longer optimised for steep diving attacks. Through the pioneering efforts by the Luftwaffe's
Jet engines allowed higher speeds which made "toss bombing" possible, a reverse dive bombing method where an aircraft snaps up from low altitude as a bomb is released, throwing it upwards like a shot put.
See also
References
- ^ Tillman, Barrett (February 2017). "The Plane That Won the War". U.S. Naval Institute. Naval History Magazine. Retrieved 26 October 2022.
- ^ Angelucci and Matricasrdi p. 142
- ^ Casey p. 87
- ^ Worth p. 170
- ^ "Douglas SBD Dauntless – The National WWII Museum – New Orleans". The National WWII Museum – New Orleans.
- ISBN 978-0-9897906-0-4.
- ISBN 978-1-59691-607-4.
- ISBN 978-0-9897906-0-4.
- ^ ISBN 0-719-544-254
- ISBN 978-0-9897906-0-4.
- ^ ISBN 0-8117-3454-4
- ^ a b c d e Boyne, Walter J. "The last of the dive bombers". Air Force magazine, December 2010, Arlingtom VA.
- ^ ISBN 978-1-86126-217-2
- ^ ISBN 0-7106-0002-X
- ISBN 978-0-7538-2605-8
- ^ ISBN 0-7006-0541-X.
- ^ The London Gazette 22 June 1918
- ISBN 1-852-602-236
- ^ Mitchell, William. Memoirs of World War I: From Start to Finish of Our Greatest War. New York: Random House, 1960
- ^ Davis, Burke. The Billy Mitchell Affair. New York: Random House, 1967.
- ^ ISBN 0-85368-802-8.
- ISBN 3-87943-844-7
- ^ Wray R. Johnson, "Airpower and Restraint in Small Wars", Aerospace Power Journal (Fall 2001 ed.), archived from the original on 30 December 2016, retrieved 18 October 2011
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- ^ ISBN 1-85532-636-1.
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- ^ ISBN 0-7607-0592-5
- ^ Smith 1982, p. 64.
- ^ Brown, 1975, p.155
- ^ Smith 1982, p. 66.
- ^ Smith 1982, pp. 66–67.
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- ISBN 0-370-10029-8.
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- ISBN 1-874023-68-9
- ^
Gunston, William: Classic World War II aircraft cutaways. Osprey, London, 1995 ISBN 1-85532-526-8
- ISBN 0-7026-0025-3.
- ISBN 0-370-00050-1.
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- ^ a b Brown 1975, p.66
- ISBN 978-1-901225-05-1
- ISBN 0-14-006814-7
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- ^ ISBN 978-0-7137-1601-6
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- ISBN 978-1-84603-973-7.
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- ^ Parsch, Andreas. US Air launched 5-inch rockets 2006.
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Bibliography
- Angelucci, Enzo and Paolo Matricardi. World Aircraft: World War II. Volume II (Sampson Low Guides). Maidenhead, UK: Sampson Low, 1978. ISBN 0-562-00096-8.
- Brown, David. Warship Losses of World War II. Arms and Armour, London, Great Britain, 1990. ISBN 0-85368-802-8.
- Brown, David. Carrier Fighters. MacDonald and Janes, London, Great Britain, 1975. ISBN 0-356-08095-1.
- Casey, Louis. Naval Aircraft. Secaucus, New Jersey: Chartwell Books Inc. 1977. ISBN 0-7026-0025-3.
- Parshall, Jonathan; Tully, Anthony (2005). Shattered Sword: The Untold Story of the Battle of Midway. Dulles, Virginia: Potomac Books. ISBN 1-57488-923-0. Uses recently translated Japanese sources.
- Smith, Peter C. Dive Bomber!. Annapolis, Maryland: Naval Institute Press, 1982. ISBN 978-0-87021-930-6.
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External links
- "Dive Bombing at Target Assures Accuracy" April 1933, Popular Mechanics – early article on dive bombing
- "Diving Artillery" , April 1942, Popular Science illustrated article on the basics of dive bombing
- Tail Brake on Do-217E Controls Its Diving Speed, November 1942, Popular Science
- battle Dive bombers compared Flight article of 1940
- "How to Dive Bomb in World War 2 Aircraft – 1943" on YouTube