AN-M74

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AN-M74


General Information
Designation: AN-M74
Type: Aerial bomb
Country of origin: United States
Manufacturer: Chemical Warfare Service, Ordnance Department, DuPont
Development: Chemical Warfare Service
Commissioning: 1945
Technical specifications
Combat weight: 3.86 kg
Length: 0.45 m
Diameter: 71 mm
Detonator: Impact fuse , time fuse
Filling :

1.22 kg PT-1 pyrogel & 0.17 kg phosphorus

Lists on the subject

The AN-M74 was an American incendiary bomb that was produced and used during World War II .

development

Development of the AN-M74 bomb began at the Edgewood Arsenal in 1943 . Based on an order from the US government, an improved version of the AN-M69 - napalm - cluster bomb was to be developed. The new bomb should have the same bomb shell but be filled with a larger amount of incendiary material and have a greater penetrating power. The engineers at Chemical Warfare Service (CWS) and DuPont took the bomb cover from the AN-M69, modified the ignition mechanism and replaced the package with the fabric straps on the rear of the bomb. Instead, they built in a tail fin that could be extended with a telescopic tube . The bomb was filled with the newly developed gel fuel PT-1 Pyrogel from DuPont. After various attempts at the test site Dugway Proving Ground in Utah in early May were the first 1,945 batches AN-M74 bombs to the XXI st Bomber Command delivered.

technology

Bombs

The bomb had an elongated fuselage shape with a hexagonal cross-section and no stabilizing wings. The bomb body was made of steel and had a gray base color. A purple stripe marked the AN-M74 as an incendiary bomb. The bomb was 0.45 m long, 71 mm in diameter and weighed 3.86 kg. The highly sensitive M142 delay detonator was located in the fuselage head . Immediately behind the fuse was a load of gunpowder . A container with 0.17 kg of white phosphorus was attached above . The remainder of the bomb body was filled with 1.22 kg of PT-1 Pyrogel. This was a mixture of gasoline , butyl methacrylate, magnesium powder , kerosene and petroleum residues, asphalt , activated carbon and sodium nitrate . In the rear of the fuselage there was a tail fin that could be pulled out via a telescopic tube , which stabilized the bomb in free fall. The bombs were packed in litter boxes and cluster bombs for dropping . The M31 (E48) cluster bomb was used most often . This was loaded with 38 AN-M74 bombs and weighed 255 kg. After the cluster bomb was dropped, it followed a ballistic curve . At a selectable height (usually 1,524 m or 5,000  feet ) the snap rings and thereby the bomb sheeting were blown away. The AN-M74 bombs were now distributed over the target area using the watering can principle . The bomb cover of the AN-M74 was constructed in such a way that the bomb could penetrate roof tiles and concrete slabs up to a thickness of 102 mm. The M142 detonator was activated on impact. This detonated with a short delay, igniting the gunpowder and phosphorus. As a result of the pressure now created in the bomb body, the ignited, gel-like fuel was thrown out of the rear of the fuselage together with the phosphorus. The pressure was sufficient to spray the burning pyrogel 2.5–5 m. The fire mix had a burn time of 4-6 minutes at a fire temperature of 1,200-1,600 ° C. The sticky , burning gel was practically impossible to extinguish with water. Compared to the conventional napalm developed at the same time at Harvard University , the PT-1 pyrogel adhered better to surfaces. It also had a longer burning time and a significantly higher fire temperature. The following versions of the AN-M74 bomb emerged:

  • AN-M74: With M142 igniter
  • AN-M74A1: With M197 igniter
  • AN-M74 (E5): Filled with 1.91 kg mustard . Total weight 3.99 kg

Cluster bombs

The AN-M74 were assembled as a bundle in litter boxes and cluster bombs . These were circular or hexagonal in cross section. This allowed them to be put together as a bundle with different equipment and weights. Well-known cluster bombs and containers for the AN-M74 were:

  • M18: (E28) with E6R2 adapter with 38 × AN-M74, weight 159 kg
  • M31 (E48): with M35 adapter with 38 × AN-M74, weight 238 kg
  • M35: with M30 adapter with 57 × AN-M74A1, weight 313 kg

commitment

The primary operational platform was the B-29 Superfortress bomber . This could be equipped with 38 M31 cluster bombs. Thus, a single bomber of this type could deploy 1,444 AN-M74 bombs. The first recorded use of AN-M74 bombs occurred on June 7, 1945 during the air raid on Osaka . During this area bombing , more than 185 tons of AN-M74 bombs were dropped on the city, along with other incendiary bombs. In this attack, almost 6 km 2 of the urban area were burned down. One of the most destructive air strikes with AN-M74 bombs took place on the night of July 28-29, 1945 on the Japanese city of Aomori . That night, 65 B-29 bombers dropped 79,116 AN-M74 bombs on the city. The large fires that followed burned the city down to 88%.

After World War II, the AN-M74 bomb was used during the Korean War . Again it was recommended that the population centers of North Korea be bombed with small incendiary bombs. The cities of Pyongyang , Hoeryong, Hŭngnam , Hamhŭng , Chongsong, Chinbo, Kusu-dong and Sinŭiju were bombed several times with cluster incendiary bombs of the type AN-M74, AN-M69, AN-M50 and AN-M54. These operations also resulted in enormous civilian casualties. In some cases, entire cities were burned to the ground by the large fires that were ignited. During the Korean War, the stocks of the AN-M74 bombs were used up, so that from then on other types of incendiary bombs were used.

See also

Web links

Commons : American WW2 incendiary bombs  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Uxoinfo, MOTIS, BOMB, INCENDIARY, M74 (data sheet), (PDF, 82.8 kB) ( Memento from February 23, 2015 in the Internet Archive )
  2. ↑ How we fight japan with fire. Popular Science May 1945, 100-109, accessed February 20, 2015
  3. ^ Kleber, BE and Birdsell, D .: Chemical Warfare Service Chemicals in Combat. Center of Military History, United States Army. Accessed February 20, 2015
  4. ^ A b National Defense Research Committee (NDRC): Summary Technical Report of Division 11, Volume 3: Fire Warfare, Incendiaries and Flame Throwers , Washington DC 1946.
  5. ^ Department of the Army Technical Manual: Technical Manual TM 3-400 Chemical Bombs & Clusters , Departments of the Army and the Air Force, May 1957.
  6. ^ A b c Joint Target Group: Study of Incendiary Bombings for Employment by the United States Army Air Forces , NARA-M1655, Washington DC October 1944, pages 14-23.
  7. ↑ a b United States Strategic Bombing Survey: Effects of Incendiary Bomb Attacks on Japan, A Report on eight Cities. United States Strategic Bombing Survey, 1947. pp. 137-138
  8. ^ Department of the Army Technical Manual: Technical Manual TO 11-1-28 / TM 9-1325-200 Bombs & Bomb Components , Departments of the Army, the Navy and the Air Force, April 1966.
  9. ^ War Department: Technical Manual TM 9-1904 Ammunition Inspection Guide , March 1944.
  10. ^ Twentieth Air Force Association. Accessed February 20, 2015.
  11. ^ The 6th Bomb Group - B-29 Performance , accessed February 20, 2015
  12. ^ Jörg Friedrich: Yalu. On the banks of the third world war . Propylaen Verlag, Munich 10/2007, ISBN 978-3-549-07338-4
  13. ^ Cumings, Bruce: Napalm on North Korea . In: Le Monde diplomatique . No. 7536 , December 10, 2004, p. 5-7 ( monde-diplomatique.de ).
  14. ↑ Crane Conrad: American Airpower Strategy in Korea 1950–1953 , University Press of Kansas 2000.