Davy Crockett (nuclear device)

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
M28/M29 Davy Crockett
DavyCrockettBomb.jpg
A Davy Crockett at the Aberdeen Proving Ground, Maryland, 1961
TypeNuclear recoilless gun
Place of originUnited States
Service history
Used byUS
WarsCold War
Production history
Variants
  • M28
  • M29
Specifications
Mass
  • M28 108.5 pounds (49.2 kg), unloaded[1]
  • M29 316 pounds (143 kg), unloaded[1]
Crew5

Elevation5-800 mils (0.3 - 45 degrees)[1]
Effective firing range
  • M28 1.25 miles (2.01 km)
  • M29 2.5 miles (4.0 km)

The M-28 or M-29 Davy Crockett Weapon System was the tactical nuclear recoilless smoothbore gun for firing the M388 nuclear projectile armed with the W54 nuclear warhead that was deployed by the United States during the Cold War. It was the first and at the time was the utmost important project assigned to the United States Army Weapon Command in Rock Island, IL.[2] It was one of the smallest nuclear weapon systems ever built, with a yield between 10 and 20 tons TNT equivalent (40–80 gigajoules). It is named after American folk hero, soldier, and congressman Davy Crockett.

History[edit]

By the year 1950, there had been rapid developments made in the use of nuclear weapons after the detonation of "Little Boy" and "Fat Man" in 1945.[3] These developments paved the way for nuclear warheads to be created at a smaller size.[4]

By the 1950s, advances in nuclear weapons technology spurred on by the first detonation of the Soviet nuclear bomb in 1949 led to great reductions in the size of nuclear weapon. By 1957, the Atomic Energy Commission (AEC) declared that it had created a small fission warhead that could be deployed for frontline use by infantrymen.[disputed ] AEC made Major General John H. Hinrichs the leader in turning the warhead into a weapon system which began at Picatinny Arsenal in New Jersey in January 1958.[4]

In August 1958, the Army started calling the BGADS as the Davy Crockett, after the American folk hero, who died at the battle of the Alamo in 1836.[5] After 4 years of testing at Forts Greeley and Wainwright in Alaska, and the Yuma Test Station in Arizona, the M28/M29 Davy Crockett entered service in May 1961.[4]

Davy Crockett Sections were assigned to United States Army Europe and Eighth United States Army armor and mechanized and non-mechanized infantry battalions. During alerts to the Inner German border in the Fulda Gap the Davy Crockett's accompanied their battalions. All V Corps (including 3rd Armored Division) combat maneuver battalions had preassigned positions in the Fulda Gap. These were known as GDP (General Defense Plan) positions. The Davy Crockett sections were included in these defensive deployment plans. In addition to the Davy Crocketts (e.g., assigned to the 3rd Armored Division), V Corps had nuclear artillery rounds and atomic demolition munitions, and these were also for use in the Fulda Gap. On the Korean peninsula, units assigned the Davy Crockett weapons primarily planned to use the passes that funneled armor as killing grounds, creating temporarily deadly radioactive zones roadblocked by destroyed tanks and other vehicles.

Production of the Davy Crockett began following the 15 August 1958 (at) Picatinny Arsenal approval of the design. There was approval for funding of 6,247 to be manufactured,[6] but a total of 2,100 were actually made. The weapon was tested between 1962 and 1968 at the Pohakuloa Training Area on Hawaiʻi island, with 714 M101 spotter rounds (not live warheads) that contained depleted uranium.[7][8] The weapon was deployed with US Army forces from 1961 to 1971.

From recent findings in 2005 the Army manufactured 75,000 depleted uranium spotting rounds that were used during the program, but only 30,000 were ever used.[9]

The 55th and 56th Infantry Platoons, attached to the Division Artillery of the US 82nd Airborne Division, were the last units equipped with the M-29 Davy Crockett weapons system. These two units were parachute deployed and, with a ½ ton truck per section (three per platoon), were fully air droppable. The units were deactivated in mid-1968.

The M388 was removed from US Army Europe (in West Germany) in August 1967.[10] The last nuclear equipped warhead was retired in 1971.[11] Contrary to popular belief, the weapons were not retired due to accuracy or safety issues with the system. Brigadier General Alvin Cowan, Assistant Division Commander of 3rd Armored Division commended the technical design of the weapon, stating that the weapon's retirement was due to use control concerns with the weapon as there was "great fear that some sergeant would start a nuclear war", along with the personnel costs associated with the weapon.[12]

The Davy Crockett was never used in actual combat.[4] Since their retirement, Davy Crockett systems are preserved in many museums throughout the United States.[4]

In 2005 the Army announced that it uncovered 600 pounds of depleted uranium from the training sites used for the Davy Crockett's inert rounds to be practice fired. They said that 12,405 acres of land could likely be tainted by these training days.[9]

M388 Nuclear Round[edit]

Annotated photograph of a training-dummy version of the M388 nuclear round[13]

Projectile, Atomic, Supercaliber 279mm XM388 for the Davy Crockett contained a W54 Mod 2 nuclear warhead. It was a very compact pure fission device weighing 50.9 pounds (23.1 kg) and when packaged in the M388 round weighed 76 pounds (34 kg). The weapon had an official yield of 20 tonnes of TNT (84 GJ) and contained 26 pounds (12 kg) of high explosives.[14][15]

Controls on the projectile included a two-position, height-of-burst switch, which could be set to 2 feet (0.61 m) and 40 feet (12 m) airburst; a safety switch with 'safe' and 'arm' positions; and a time setting dial that allowed a time delay between 1 and 50 seconds before the fuze armed. If the time delay was greater than the time-of-flight, the weapon would hit the ground before it armed and not detonate. The time dial also had a 'safe' setting, and so acted as a second safety switch.[16][15]

The complete round weighed 76 pounds (34 kg). It was 31 inches (79 cm) long with a diameter of 11 inches (28 cm) at its widest point; a subcaliber piston at the back of the shell was inserted into the launcher's barrel for firing.[17] The M388 atomic projectile was mounted on the barrel-inserted spigot via bayonet slots. Once the propellant was discharged the spigot became the launching piston for the M388 atomic projectile: this was necessary because the fission round could not be subject to high acceleration and the spigot/piston, acting as a "pusher tube", facilitated this.[18] In flight, four fins on the end deployed to stabilize trajectory and flight.[4]

Practice Rounds[edit]

The M390 practice round was outwardly similar to the nuclear round and was designed to be a ballistic match to it. It contained 16 pounds (7.3 kg) of Composition B high explosive that was detonated by an electrical switch on impact with the ground. The practice round had a significant destructive effect in its own right and was intended to be used in combat in an emergency situation. A further type of dummy training round, the M421, was completely inert and not intended to be fired.[19]

Launcher[edit]

Propellent charge is loaded
Launch piston is inserted
The M-388 nuclear round is attached to the launch piston
Loading a Davy Crockett M29 Launcher[20]

The M388 could be launched from either of two launchers known as the Davy Crockett Weapon System(s): the 120 mm (4.7 in) M28, with a range of about 1.25 mi (2.01 km), or the 155 mm (6.1 in) M29, with a range of 2.5 mi (4.0 km).

The limited firing range was due to the combination of poor aerodynamic of the "watermelon with fins" (some soldiers referred to the warhead as the "atomic watermelon"[4]) type shape and the warhead's inability to withstand being fired like a traditional artillery round.[disputed ] This meant that it had to be fired out of a short range recoilless rifle. [11]

Both weapons fired the same projectile, propelled using a separate cartridge. The smaller M28 used a 5 kg (11 lb) explosive cartridge to launch the warhead. The larger M29 used an 5 kg or a 8.5 kg (19 lb) propellant charge, depending on the desired range.[21] The launcher systems were muzzle loading weapons. As they were intended for a very low rate of fire a breechloading mechanism was unnecessary.[18]

Davy Crockett launchers were either mounted on a tripod launcher transported by an M113 armored personnel carriers, or they were carried by a Jeep (the M38, and later the M-151). The Jeep was equipped with an attached launcher for the M28 or the M29, as required, whereas the Davy Crockett carried by an armored personnel carrier was set up in the field on a tripod away from the carrier. The M113 was equipped to carry up to ten nuclear rounds.[22]

Weapons assigned to infantry units were carried in M113s, those allocated to airborne units were carried on Jeeps.[23]

The M28 launcher was also equipped with a 20mm spotting rifle - a single-shot weapon that fired depleted uranium[7] rounds using a high–low system. These rounds flew a similar trajectory to the nuclear projectiles and produced white smoke when they landed, helping determine range.[24]

The Davy Crockett was fired remotely. A mechanically-operated detonator at the end of 22 m (72 ft) of detonating cord led to the propellant charge.[25] The M388 nuclear projectile was attached to a titanium piston by means of a bayonet mount. When fired, the piston was blown out of the tube by the detonating propellent. The piston was hollow and filled with high-pressure gas from the explosion, this pressure broke shear pins that connected the piston to the nuclear projectile, detaching it after a few meters of flight.[26] The piston would hit the ground several hundred meters in front of the weapon while the projectile continued to the target.[27]

The Davy Crockett's were operated by a five-man crew, the squad consisting of a Commander, Gunner, Assistant Gunner, Loader and Computer.

The commander of the M388 could issue use and have the weapon fired in a matter of minutes. [28]

The weapon was made from lightweight metals—the tripod was aluminum, the barrel was titanium[29]—and it was possible to break the smaller M28 weapon into three loads that could be carried by the crew, with the other two crew carrying two radios and accessories.[30] The weight of the M28 launcher was 185 lbs while the bigger M29, weighed 440 lbs.[4]

Operating the M28 or M29 versions of the weapon with a three-man crew was also possible.[31]

In the 3rd Armored Division in Germany in the 1960s many Davy Crockett Sections (all of which were in the Heavy Mortar Platoons, in Headquarters Companies of Infantry or Armor Maneuver Battalions) received what became a mix of M28 & M29 launchers [e.g., one of each per D/C section]. Eventually, the M28s were replaced by M29s, so that both the armored personnel carriers and the Jeeps carried the M29.

Effects[edit]

The weapon's Mushroom cloud, July 17, 1962
In 2008
The Little Feller I nuclear test site

Both recoilless guns proved to have poor accuracy[4][disputed ] in testing,[11][disputed ] so the shell's greatest effect would have been its extreme radiation hazard. The M388 would produce an almost instantly lethal radiation dosage (in excess of 10,000 rem, 100 Sv) within 500 feet (150 m), and a probably fatal dose (around 600 rem, 6 Sv) within a quarter mile (400 m).[32] The weapon did not have an abort function; if fired, the warhead would explode.[33]

Because the Davy Crockett has such a powerful warhead and has a limited firing range, the weapons blast was also a danger for the crew that manned it along with its target. Due to this the Army created a standard for the crew to follow when firing the M388. They advised the soldiers to hide their bodies at a rear sloped hill and laying in prone position of the ground with their neck and head covered.[4]

The warhead was tested on July 7, 1962 in the Little Feller II weapons effects test shot, and again in an actual firing of the Davy Crockett from a distance of 1.7 miles (2.7 km) in the Little Feller I test shot on July 17. This was the last atmospheric test detonation at the Nevada Test Site.

Information and recorded data from test-firing inert rounds showed the recoilless rifles to be "shockingly inaccurate" and led to the realization that the weapon was "too inaccurate to deliver even low-yield nuclear fires".[11][disputed ]

Spending[edit]

Development of this weapon proved to be costly in all aspects of design, modifications, and labor. Over a 5 year period from 1958-1963, total expenses soared to nearly $20 million USD, which would be $170 million USD today. The initial allotted development costs varied from year to year, starting with $1.1 million in 1958, $9.15 million in 1959, $5 million in 1960, $2.4 million in 1961, $1.5 million in 1962, and $250,000 in 1963.[2] In comparison to Fat Man, which cost nearly $2 billion USD, The Davy Crockett weapon system was relatively cheap.

Proposed German military use[edit]

One of the most fervent supporters of the Davy Crockett was West Germany's defense minister Franz Josef Strauss, in the late 1950s and early 1960s. Strauss promoted the idea of equipping German brigades with the nuclear weapon, to be supplied by the US, arguing that this would allow German troops to become a much more effective factor in NATO's defense of Germany against a potential Soviet invasion. He argued that a single Davy Crockett could replace 40–50 salvos of a whole divisional artillery park – allowing the funds and troops normally needed for this artillery to be invested into further troops, or not having to be spent at all. US NATO commanders strongly opposed Strauss's ideas, as they would have made the use of tactical nuclear weapons almost mandatory in case of war, further reducing the ability of NATO to defend itself without resorting to atomic weapons.[34]

Concerns and potential problems[edit]

Radiation Exposure[edit]

The Davy Crockett Weapon System' use of depleted uranium in the spotting round lead to some concerns about troop exposure to the material, however studies indicated that there was no risk of exposure to the material during use of the weapon.[2]

As a nuclear munition however, an exceptional strong safety program was required. This included providing render-safe procedure documentation to explosive ordnance personnel before deliver of the first warheads.[2]

Accuracy[edit]

It is alleged that test shots tended to be fairly inaccurate causing the warheads to be hundreds of feet off of the target mark.[11] Program documentation for the weapon indicates that the weapon had a circular error probable (CEP) of 50 m (160 ft)[2]. Brigadier General Alvin Cowan, Assistant Division Commander of 3rd Armored Division commended the technical design of the weapon after its retirement while citing other reasons for its retirement.[35]

Other uses of W54 Warhead[edit]

The W54 warhead used by Davy Crockett was initially developed for both it and the AIM-4 Falcon air-to-air missile under the designation of XW-51. However, the development of the warhead was reassigned to Los Alamos Scientific Laboratory in January 1959 and redesignated the XW-54. This produced the Mark 54 mod 0 and Mark 54 Mod 2 warheads for Falcon and Davy Crockett use respectively, which were only distinguishable by the environmental sensing device employed. Later, the Special Atomic Demolition Munition (SADM - sometimes designated the B54) was developed and saw service between 1964 and 1989. SADM was so different from the W54 warhead that consideration was given to renaming the weapon with its own unique mark number. Mod numbers between the Mark 54/W54 and B54/SADM are not shared. A later development of the W54 was the W72 warhead for the AGM-62 Walleye television-guided glide bomb system.[14][17]

Museum examples[edit]

A Davy Crockett casing preserved in the United States Army Ordnance Museum

The following museums have a Davy Crockett casing in their collection:

Notes[edit]

References[edit]

Citations
  1. ^ a b c The Davy Crockett Weapons System (1961), pp.5-7
  2. ^ a b c d e Project Management of the Davy Crockett Weapons System. https://apps.dtic.mil/dtic/tr/fulltext/u2/a470429.pdf: U.S. Army Weapons Command. 1962.CS1 maint: location (link)
  3. ^ "Hiroshima and Nagasaki Bombing Timeline". Atomic Heritage Foundation. Retrieved 2021-04-24.
  4. ^ a b c d e f g h i j Seelinger, Matthew (2016-09-20). "The M28/M29 Davy Crockett Nuclear Weapon System". Army Historical Foundation. Archived from the original on 2017-02-06. Retrieved 2021-04-28.
  5. ^ "TSHA | Crockett, David". www.tshaonline.org. Retrieved 2021-04-24.
  6. ^ Network, Warfare History (2020-04-27). "Small but Deadly: How America's Davy Crockett Rocket Launched Nuclear Bombs". The National Interest. Retrieved 2021-04-24.
  7. ^ a b Miller, Erin (September 1, 2010). "Military says DU at PTA likely harmless: Army reports 'no likely adverse impacts' from spotting rounds". West Hawaii Today. Retrieved September 2, 2010.
  8. ^ "Pohakuloa Training Area Firing Range Baseline Human Health Risk Assessment for Residual Depleted Uranium" (PDF). Cabrera Services Radiological Engineering and Remediation. Hawaii, US: Army. June 2010. Retrieved September 2, 2010.[dead link]
  9. ^ a b Roeder, Tom (2015-10-18). "Hundreds of pounds of depleted uranium likely buried at Fort Carson, Army says". Colorado Springs Gazette. Retrieved 2021-04-24.
  10. ^ History of the Custody and Deployment of Nuclear Weapons(U): July 1945 through September 1977; "Prepared by Office of the Assistant to the Secretary of Defense (Atomic Energy) February 1978", Page B-7.
  11. ^ a b c d e "Back to the Drawing Board: the Davy Crockett 'Tactical' Nuke". Military History Matters. 2020-01-20. Retrieved 2021-04-24.
  12. ^ Proceedings of the Tactical Nuclear Weapons Symposium (PDF) (Report). AEC and DoD. 1969. p. 173.
  13. ^ The Davy Crockett Weapons System (1961), p.37
  14. ^ a b History of the Mk 54 Weapon (Report). Sandia National Labs. February 1968.
  15. ^ a b Safety Rules for Peacetime Operations with the DAVY CROCKETT/MK54 Mod 2 Atomic Weapon System (Report). Headquarters, Department of the Army. 1 November 1961. p. 137-153. MVS-020107-001.
  16. ^ The Davy Crockett Weapons System (1961), pp.42-43
  17. ^ a b "List of All US Nuclear Weapons", USA weapons, Nuclear weapon archive, retrieved October 20, 2006.
  18. ^ a b Engineering Design Handbook Recoilless Rifle Weapons Systems (PDF). Alexandria, VA: US Army Materiel Command. 15 January 1976. pp. 1–32.
  19. ^ The Davy Crockett Weapons System (1961), pp.43-44
  20. ^ The Davy Crockett Weapons System (1961), pp. 133-134
  21. ^ The Davy Crockett Weapons System (1961), p. 50
  22. ^ The Davy Crockett Weapons System (1961), p. 23
  23. ^ The Davy Crockett Weapons System (1961), p. 129
  24. ^ The Davy Crockett Weapons System (1961), p. 44
  25. ^ The Davy Crockett Weapons System (1961), p. 52
  26. ^ The Davy Crockett Weapons System (1961), p. 36
  27. ^ The Davy Crockett Weapons System (1961), p. 48
  28. ^ Network, Warfare History (2020-04-27). "Small but Deadly: How America's Davy Crockett Rocket Launched Nuclear Bombs". The National Interest. Retrieved 2021-04-24.
  29. ^ The Davy Crockett Weapons System (1961), p. 8
  30. ^ The Davy Crockett Weapons System (1961), p. 21
  31. ^ The Davy Crockett Weapons System (1961), p. 112
  32. ^ "Section 5.6, Mechanisms of Damage and Injury", Nuclear Weapons (FAQ), Nuclear weapon archive, retrieved October 20, 2006.
  33. ^ "Davy Crockett: King of the Atomic Frontier". www.damninteresting.com. Retrieved 2015-07-24.
  34. ^ "Bedingt abwehrbereit". Der Spiegel (in German) (41). DE. 1962.
  35. ^ Proceedings of the Tactical Nuclear Weapons Symposium (PDF) (Report). AEC and DoD. 1969. p. 173.
Bibliography

Further reading[edit]

External links[edit]