TB Torpedo Bomber
T Torpedo and bombing
Launching torpedoes by relatively undetectable submarines is not without its disadvantages. Submarines are slow as compared to torpedo dispensing aircraft. If a submarine is to engage a target about 100 nautical miles from its position, it might take many hours to navigate the distance underwater. Thus, to ensure stealthy operation, a submarine's slow and careful progress will operationally limit it, especially if the operation is taking place through a hostile monitored region. Once a torpedo is launched, the submarine's location is likely to be revealed. Evasive maneuvering during the submarine's withdrawal to safer waters location may be needed to ensure survivability. This can take hours during which time the submarine is vulnerable to counter attack from surface, subsurface, and airborne platforms. Thus, airborne platforms may be more desirable to deliver torpedoes from safe and undetected standoff positions. Some aircraft can take less than an hour to deploy torpedoes and return to base without detection. However, if such aircraft are detected, they too are vulnerable to destruction.
Discussion of the use of aerial torpedoes began several years before the start of the Great War. For the duties of bomb and torpedo aircraft the flying boat type of machine seemed ill-suited; the conditions are such as would indicate the two-float type as necessary. The latter admitted of the bomb-magazine or torpedo-cradle being arranged centrally beneath the fuselage, from which position, by suitable release mechanism, the missile or torpedo can be readily let fall. The aeroplane for the duty in question would need to be somewhat larger and of greater carrying capacity than the prevailing standard; the contemporary 21-in. torpedo, for example, weighed approximately 1 ton, and would require a machine of about 4 tons gross lifting power. The older model, the 18-in. weapon, weighed about 1,200 pounds, and would require a machine with a gross lifting-power of 2 tons, the latter being not very much in excess of the largest machines in service.
In patent No. 1,032,394 of July 16, 1912, Bradley A. Fiske (1854-1942), U.S. Navy, presented a method and apparatus for delivering submarine torpedoes from aircraft in which the torpedo was first transported through the air to a point of desired proximity to a target by means of an aircraft and then the torpedo was trained in the desired direction, after which the propelling mechanism of the torpedo is started, and then the torpedo was released to fall by gravity to the water. In the apparatus, a strap was employed for retaining the torpedo below the aircraft and a manually controlled lever releases a latch for said strap, the said lever also actuating transmitting mechanism to operate the starting device for the propelling mechanism of the torpedo.
The British Naval Air Service was the first to test torpedoes from airplanes in World War I. In 1911, the Royal Navy graduated it's first aeroplane pilots, Lieutenants Longmore (from Australia), Gregory and Samson. Later Lieutenant Arthur Longmore, as a pilot in the Royal Naval Air Service, flew an aircraft to the world's first water landing using pontoon shaped airbags. On July 28, 1914 [some sources erroneously report 1915], the first aerial torpedo was launched from a Royal Navy three-bay Short Folder seaplane by Lt. Arthur M. Longmore [Longmore retired as an Air Chief Marshal during WWII].
By November 1914 some experiments were reported as having been made in Germany, indicating a direction in which aircraft may become an actual source of danger to even the most formidable battleship or cruiser. It was said that a Zeppelin had been fitted with means of discharging a White-head torpedo with complete success.
The first use of the torpedo-plane in combat is unclear. Bradley A. Fiske, in his diary entry for 20 February 1916, records that he "... Rec'd letter yesterday from Comdr. J. P. Morton, comdg U. S. S. Scorpion at Constantinople saying that a British officer, belonging to the British fleet in the Agean Sea had flown over the land into the Sea of Marmora in a large hydroaeroplane carrying a Whitehead torpedo, launched the torpedo at a Turkish transport and sunk it. This is my invention, patented July 16, 1912. Hurrah ! I have invented a new method of warfare, and it is successful."
Others claim that the torpedo-plane was first used successfully in combat by the Germans. The British steamer Gena of 2784 tons was sunk 01 May 1917, by a torpedo discharged from a German seaplane off Suffolk, England. The details of this startling event - which introduced a new method of naval attack - were given in the affidavit signed at Newcastle by the American seaman, Oscar C. Findley to the American Consul. The affidavit reads: "While I was aboard the British steamer Gena in the Channel on May 1, two German seaplanes, 300 feet aloft, passed near by. Without any warning whatever, one dropped a torpedo to the water and the missile sped along the surface and struck the Gena. We sank in thirty-fire minutes. A Norwegian steamer which approached us was similarly attacked. We fired while sinking and brought down one seaplane. The other fled. Two Germans on the destroyed plane were picked up by the same trawler that rescued survivors from our ship."
U.S. Navy Admiral Bradley Fiske wrote [The Torpedoplane. By Rear-Admiral Bradley. A Fiske, U.S.N. Flying, March 1917. 1630 words. Illustrated.] that "The torpedoplane, which will become an important factor in naval warfare in the near future, is a scheme whereby a regular Whitehead torpedo can be launched as effectively from an airplane as it can from a torpedo boat or destroyer. The destroyer goes toward the enemy at a speed of about 30 knots and launches a torpedo from its deck. The torpedo goes ahead under its own power, and, if aimed correctly, strikes its target under the water-line, disables and sinks it. With the torpedoplane the aviator approaches his target from a height of several thousand feet, and when several miles away volplanes close to the water, and when a few feet above the water and pointing toward his target releases the torpedo. The torpedo falls into the water exactly the same as if dropped from a destroyer. An Italian aviator tried it out two or three years ago and hit the target nine times out of ten at 3000 yards. A year ago a British naval lieutenant sank four Turkish vessels in the sea of Marmora, using 14-inch Whitehead torpedoes weighing 731 pounds each."
The reference to Lieut. Boyle of the British Navy sinking four Turkish vessels in the sea of Marmorais in error. The following statement was issued by the British Admiralty 21 May 1917 "The following decorations have been awarded to officers and men of the submarine E-14, which, operating in the Dardanelles and the Sea of Marmora, sank Turkish gunboats and a transport. Victoria Cross to Lieutenant Commander Edward Boyle." There are vague contemporaneous reports that a British aviator torpedoed four Turkish vessels in July 1916, but these must confabulate the Boyle account. For some years a torpedo 14 ft. long and 14 in. in diameter was considered large enough, though it had a very limited effective range and some questioned the effectiveness of the small warhead. The point of mentioning the Boyle incident may have been that even such small torpedos could be effective, and could be carried by aircraft. The 18-inch torpedo coming into general use was a far more effective weapon than the 14-inch torpedo. The 18-inch torpedo had a greater range, and would probably sink any battleship it might strike, instead of merely disabling her for a time.
Soon thereafter Fiske wrote [Defending America with Torpedoplanes. By Rear- Admiral B. A. Fiske, U. S. Navy. Popular Science Monthly, May, 1917] "The torpedoplane may prove to be revolutionary in naval tactics, as was the advent of the armored ship. The torpedoplane is a combination of the use of the torpedo and airplane. It is possible to launch a torpedo from an airplane, and the torpedo will then propel itself in the direction of its target. The airplane carrying the torpedo will offer a poor target for a gun mounted on a rolling platform on account of the motion and the difficulty of ranging."
The US Navy first experimented with aerial torpedoes in late 1917, when a 400-pound dummy torpedo was dropped from a seaplane and ricocheted back into the air, almost hitting the plane. Since the aircraft of the day could lift only about 600 pounds of bombs or other ordnance, and the normal shipboard or submarine torpedo weighed 1,500 pounds or more, the torpedo bomber was not yet a reality.
U.S. Navy Admiral Bradley Fiske received another patent for an air dropped torpedo in 1921 [patent 1,379,972 issued May 31, 1921. Admiral Fiske's invention consisted of a mobile torpedo similar to the torpedoes projected under water by submarines, supported on an airplane frame directly below the aviator's seat and so arranged that by pulling a single lever it is freed and its propelling engine started. The torpedo-plane is launched either from land or from the deck of a ship, rises some 6000 feet and stays at that elevation until its target is sighted, whereupon it rapidly descends at a precipitous angle. If the objective was a weak vessel the plane may approach to within 1500 yards before firing; but if armed vessels are attacked this distance was increased. The torpedo's nose at the moment of release is pointed directly at the target. The release occurs when the plane is about 20 feet above water. The torpedo automatically takes a certain depth and a speed of about 35 miles per hour.
Following the Great War, the development of reliable aircraft engines and refinements in torpedo designs produced the first operational torpedo bombers. American development of aircraft carriers was concurrent with those in Europe, and as they developed, so did a new breed of aircraft -- the torpedo bomber. The US Navy's first torpedo aircraft was the twin-engine converted Martin TM-1, modified Army bomber. The MT [Martin Torpedo] was the United States Navy version with an MB-1 fuselage and MB-2 wings. Eight were built, and later designated the TM-1. Others included the single-engine Douglas DT and the twin-engine T2D float planes. By the late 1920s and early 1930s, the US Navy was equipped with Martin T3M and T4M biplane torpedo bombers capable of operation on floats from the water, or fitted with wheels, from the decks of aircraft carriers. The Great Lakes Company also produced a variant of Martin's T4M design for the Navy.
There were only two design competitions for torpedo bombers during the thirties. One in 1934 produced the Douglas TBD-1 and one in 1939, the Grumman XTBF-1. In the 1930s, Douglas Aircraft Company introduced the first TBD Devastator which became the Navy's leading torpedo bomber. The Navy obtained 130 TBDs and production was completed in 1939. In early November 1939, the U.S. Navy approached a number of aircraft manufacturers to design and build a replacement torpedo bomber for the aging Douglas TBD-1 Devastator and Grumman Aircraft Company received the contract. The TBF, being four years younger and fitted with a more powerful engine, had much better performance. It also carried an additional gun, armor for the pilot and crew, and self-sealing fuel tanks.
Because maritime operations in World War II did not typically involve the risk of encountering enemy high performance fighters (except directly along an enemy coastline or -- for the Germans -- after the emergence of the Anglo-American escort carrier) that deep-penetration missions into an enemy's heartland did, single or multiengine aircraft of modest performance could often make contributions all out of proportion to their true abilities. The Savoia-Marchetti S.M.79-II Sparviero ("Sparrow") torpedo bomber, an Italian trimotor that enjoyed surprising success against Allied shipping in the Mediterranean, exemplified this. Armed with two torpedoes, it was largely responsible for the 63 Royal Navy ships lost to Italian air attack in the Mediterranean; indeed, in the words of one British aeronautical historian, "the exploits of Italy's torpedo-bombing squadrons equipped with this type, the Aerosiluranti, were almost legendary." The German Junkers Ju 87 Stuka dive bomber and the Heinkel He 111 torpedo bomber, and the British Bristol Beaufort and Vickers Wellington constitute other examples of less-than-fully successful airplanes that nevertheless exerted significant influence within the maritime arena, particularly against merchant convoys.
The Grumman Avenger, or Torpedo Bomber F (TBF), with F being the Navy's designated letter for the Grumman factory, was replaced by General Motors Avenger TBM, with M being the Navy's designated letter for the General Motors factory. General Motors converted automobile plants into airplane manufacturing facilities during World War II, and agreed to produce combat airplanes quickly and in quantity. On January 21, 1942, Eastern Aircraft was born, comprised of General Motors plants in Linden, Trenton and Bloomfield (all in new Jersey), Baltimore (Maryland) and Tarrytown (New York). Plants were emptied of their automobile equipment and converted into airplane manufacturing. As the war went on, streamlined manufacturing and sub-contracting increased the output of planes.
Lack of experience in launching the aircraft torpedo led to a preference for the aerial bomb, with which most pilots were familiar. This preference was intensified by the low-altitude, slow-speed tactics required for torpedo launch. The problems with such tactics were seen at the Battle of Midway in June 1942. In this battle, torpedo launching runs were made from over the horizon at an altitude of 50 feet and a speed of 110 knots by inadequately protected planes against very strong enemy fighter and anti-aircraft cover, resulting in heavy losses. Thirty-seven out of 41 planes were lost without scoring a single torpedo hit.
By the end of the war, the Avenger had become one of the three most numerous carrier aircraft of all time. The total production of 9,839 Avengers was exceeded only by 12,570 Corsairs (a naval attack fighter) and 12,275 Hellcats (another fighter used for anti-submarine work, to provide air cover for invasion forces, and to provide close air support for ground troops).
Torpedo Attacks and Hits for
U.S. Carrier-Based Aircraft
(7 Dec 1941 to 31 May 1945)
|Class of Targets||Number of Attacks*||Number of Hits||Percentage of Hits|
|Battleships and carriers||322||162||50|
*An "attack," is defined as one plane attacking one ship with a torpedo.
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