M8 (missile)
The M8 , official name Rocket, HE, 4.5-inch, M8 (in German about rocket, high explosive, 4.5-inch, M8 ), was a military missile developed by the United States Army during the Second World War . The rocket was stabilized by a folding tail and had an electric ignition. Originally designed as air-to-air missile planned, it was as air-to-ground and surface-to-surface missile used. By the end of the war in 1945, over 2.5 million rockets were produced, after which the M8 was replaced by an improved successor. Despite its brief service, the M8 was an important step for the American military in gaining knowledge from development, production and use.
development
During the First World War , the American scientist and rocket pioneer Robert Goddard carried out experiments in the Aberdeen Proving Ground on how rocket technology could be used militarily. His assistant at the time, Clarence Hickman , had the idea of using missiles as aircraft armament. These rockets were to be launched from tubes that were attached under the wings . With the end of the First World War, the US Army stopped further missile development.
In the 1930s, US Army officer Leslie Skinner continued the experiments of Goddard and Hickman. The United States Army Ordnance Department gave him little support and was transferred to Hawaii in 1938 . With the outbreak of World War II , the USA noticed the technical lag in rocket technology compared to the United Kingdom , the Soviet Union and the German Reich . The then established National Defense Research Committee (NDRC) took over the coordination of research for military purposes. Hickman, now in charge of a section of the NDRC, made sure that Skinner was transferred to the Indian Head Powder Factory in November 1940 to continue the research work on the missiles for the US Army. In addition to the M8, Skinner developed the anti-tank missile Bazooka .
The intention of the NDRC was initially to develop an air-to-air missile with a proximity fuse. The missile should be used in particular in the fight against enemy bombers . With the proximity fuse, the missile would not have to hit the aircraft directly, because a flyby would trigger the detonation. Splinters and detonation waves should then hit the aircraft. Skinner built as the main developer, with the help of other people from the Army Ordnance Department, the NDRC and the US Navy , a prototype that was launched on May 29, 1941 for the first time from the ground. The missile hull formed a decommissioned 4.5-inch fire extinguisher , which also determined the later diameter of the M8. The initially rigid guide surfaces were replaced by retractable ones so that the rocket could be launched from a tube. The rocket was initially known under the test designation T12. In December 1941, the prototype achieved stable flight characteristics.
The research facility at Wright Field took on the design of an airborne missile launcher. The first take-off in the air took place on July 6, 1942; the rocket launcher was mounted under a wing of a Curtiss P-40 . Other plans were to develop a reloadable rocket launcher for the bomb bay of a Douglas A-20 . Since the M8 could theoretically also be fired in directions other than the aircraft's flight direction thanks to the launch tube, experiments with rocket launchers firing upwards and backwards followed.
At the time, the Ordnance Department and NDRC were very optimistic about the progress of the M8 development, so commitments were made about the availability of the missiles for Operation Torch, which was scheduled for November 1942 . The initial requirement of 15,000 missiles has been increased to 600,000. But then the project stalled; In addition to many technical problems, the supply of the new propellant powder became a bottleneck. In order to be able to provide more resources for development and later for construction, the Ordnance Department decided to expand the operational profile to a surface-to-surface missile for the ground forces . The different types of application should be made possible by different detonators : proximity detonators for the air-to-air missile or impact detonators for the surface-to-surface missile. Since the war situation later turned in favor of the Allies and enemy aircraft no longer posed a major threat, the variant with a proximity fuse was never used. However, the concept was incorporated into a long-term development of future air combat weapons. Instead of the proximity fuse , the United States Army Air Forces also equipped the M8 with an impact fuse so that it could be used as an air-to-surface missile.
The mass production finally began only in February 1943; However, accompanying tests showed some weaknesses in the construction and execution. Production was stopped in June 1943 in order to improve the M8. Old supply contracts were terminated, new ones were concluded with Revere Copper and Brass from Rome (New York) . Personnel and organizational restructuring were also carried out. While Skinner was transferred to Europe, Gervais Trichel took over the missile development department newly established within the Army Ordnance Department, with significantly increased staff and budget.
The missile went through several development cycles. The improvements in the M8A1 were a reinforced engine body and the suitability for use at higher ambient temperatures . The M8A2 had a smaller warhead and reinforced casing and the M8A3 improved control surfaces. Only the final model T22 worked satisfactorily over a wide temperature range.
technology
The missile body consisted of two main parts, the warhead and the missile engine. The warhead consisted of a metallic casing, the head detonator with booster charge and an explosive tube that protruded far into the rocket engine. To protect the explosives from the heat of the ignited propellant charge, the outside of the explosive tube was insulated with clay . The warhead and the tube were filled with TNT explosives , or an inert substance in the M9 exercise variant. The explosive tube protruding into the engine ensured that its components were used to generate additional fragments during the explosion. The warhead casing was threadedly connected to the motor casing.
A new fuse , the M4, had to be designed for the rocket , as the fuse of an artillery projectile could not be used. In the case of artillery projectiles, the arming of the detonator ( front pipe safety device ) is based on the principle of twist and longitudinal acceleration; on the other hand, only the longitudinal acceleration could be used in the case of the stabilized M8. Focusing takes place in two steps; First, when the rocket was launched, the detonator had to experience forward acceleration, and then this acceleration had to end after the engine burned out. The propellant rods were burned about 26 meters after take-off. The intention was to avoid accidental ignition before take-off and during the short acceleration phase. However, the detonator was armed at a relatively low acceleration of 100 g , which is comparably little compared to an artillery projectile (approx. 20,000 g) or mortar shell (approx. 4,000 g). As soon as the fuse pin of the detonator was pulled, no major vibrations were allowed to take place when loading the launch tube. The percussion fuse could be set for immediate or delayed (0.1 s) ignition. If ignited immediately, the explosion occurred on the surface; The shock wave and splinter spread over a large area. With delayed ignition, the missile penetrated the target or a deep explosion crater was formed.
The metal casing of the motor was cylindrical and shaped into a nozzle at the rear end . It contained the propellant charge and the ignition device. The folded-in guide surfaces were mounted on the outside of the nozzle. When the missile left the launch tube, the six baffles flipped open and stabilized the missile's flight. A predetermined breaking point in the motor casing ensured that the warhead and motor were separated if the pressure inside the motor casing was too high. The warhead was ejected forward and thus had a significantly reduced range of only about 100 to 1000 meters. This could happen if the nozzle was clogged or, on early models, if the ambient temperature was too high.
The early versions of the M8 only worked safely with the factory-delivered propellant charge in certain air temperature ranges, for example up to 32 ° C in the first version. When using it beyond these ambient temperature ranges, the propellant charge had to be reduced by a few rods on site.
The propellant charge consisted of 30 ballistite charge bars . Three rods each were threaded onto a holding wire ; There was enough play between the wire and the rod so that they could burn off on the outside as well as on the inside. A total of ten retaining wires were stretched in a ring within the casing. Two pouches filled with black powder were attached on each side. These bags were designed to ensure that the top section of the propellant charge was also safely lit.
The ignition device consisted of black powder and an electrically triggered detonator . The detonator was electrically connected to contact rings on the outside of the igniter. In the later version T22, a connector was also mounted on a cable. The igniter was fixed in the nozzle with cement ; after igniting the propellant charge, it was ejected from the nozzle by the spreading gases.
The rocket was loaded into the launch tube from behind. A holding device on the launch tube held them at the lower edge. Two contact brackets of the launch tube were folded down onto the contact rings of the ignition device and thus established the electrical connection between the rocket and the starter.
Use and further development
Air-to-surface missile
The test starter T30 was developed for aircraft, which was then standardized as M10, M14 and M15. The three starters only differed in the material of the starting tube. The first deployment of the Army Air Forces took place around the turn of the year 1943/1944 against Japanese targets in Burma , as the first use of an American air-to-surface missile. However, the M8 showed only a weak effect against fortified or armored targets.
In use, the great air resistance of the launch tubes was a disadvantage. The High Velocity Aircraft Rocket (HVAR), which has meanwhile been developed by the Navy, demonstrated with a two-point suspension that the launch option was entirely without a launch tube. As the plane moved, the passing air stabilized the missile. Dissatisfied with the slow elimination of the poor reliability of the early M8 missiles and because of the better accuracy of the HVAR, the Air Forces switched to Navy development from the summer of 1944. Since the Army Air Forces had large quantities of the M8 in stock and the HVAR was initially not available in the necessary quantities, upgrade kits were provided to convert the missiles to the new launch method. This included eyelets around the missile body and larger guide surfaces, which improved accuracy as an additional advantage. A cable with a plug was attached to the lighter because the electrical connection was no longer made via the launch tube.
Since the HVAR was now plagued by delivery problems for the fast-burning propellant powder, the Ordnance Department had the idea of developing a new missile that combined the technology of the M8 and some of the properties of the HVAR. With the same diameter, the Super 4.5 was significantly longer, had fixed guide surfaces and a larger warhead. It was developed in December 1944, but was no longer used in combat operations.
Surface-to-surface missile
The explosive power and range of the M8, originally designed as an air-to-air missile, allowed the United States Army to use it as a surface-to-surface missile. It could not replace guns , but complement it in some areas. The range and, above all, the accuracy were lower, but the lack of recoil made it possible to use light multiple rocket launchers mobile and to fire many rockets within a short time.
Mainly, the M8 missile was used in multiple rocket launchers as a means of barrage . In this application, the missile was considered effective, since the accuracy played a subordinate role.
The T27 "Xylophone" was an 8-fold bowler who usually on the loading area of a 2.5-ton trucks as GMC or Studebaker US6 was installed. The first operational test of the T27 launcher took place in the summer of 1944 off Brest during the Battle of Brittany ; then the launcher was used on a large scale in Europe. The 18th Field Artillery Battalion was completely converted to the T27 launchers. It turned out to be disadvantageous that the large amount of smoke generated during take-off and the exhaust flames could easily be noticed by the enemy and thus revealed the position of the fire . The " shoot-and-scoot " tactic was introduced as a countermeasure . This provided for a quick change of fire position after shooting in order to avoid the enemy counterfire .
The T34 Calliope was a 60x launcher that was installed on an M4 Sherman . These were used on a small scale by the Third United States Army in Europe.
Despite the multiple use of the two multiple rocket launchers, the Army's attitude remained ambivalent; they were considered a temporary solution. None of the launchers was standardized, they remained in the test status.
The M12 single launcher was developed for use in the Pacific War . The intention was to be able to fight fortified positions in direct fire , such as strongly fortified bunkers in the impassable jungle . The M12 launcher consisted of a simple frame with a launch tube for single use. In terms of weight, it could be carried by one person on his back. This enabled the launcher to be used in areas that were not accessible to gunfire. The launcher was used in the Battle of Okinawa towards the end of the war .
T27
T34
M12
To improve the poor accuracy, the M16 missile was developed as a successor . The most important difference was the flight stabilization by means of twist. The M16 was introduced shortly before the end of the war; only one use in Germany is known.
During the Second World War, the Soviet Union with the Katyusha , Great Britain with the land mattress and the German Reich with the Nebelwerfer used comparable surface-to-surface missiles from multiple launchers.
Technical specifications
- Type: surface-to-surface and air-to-surface missile
- Units built: 2,537,000
- Length: 81.2 cm
- Diameter: 11.4 cm (4.5 inches)
- Weight: 17.2 kg
- of which explosives: 2 kg
- of which propellant charge: 2.1 kg
- Range: 3800 m
- Speed: 264 m / s; 950 km / h
Others
The M8 is not to be confused with the 4.5-inch Beach Barrage Rocket , a similar rocket used by the US Navy that also dates back to World War II. The multiple rocket launchers used were T44 and T45.
literature
- OS 9-69: Rockets and Launchers, All Types , Ordnance School, Aberdeen Proving Ground, February 1944 [4]
- Technical Manual TM 9-395 4.5 ″ Aircraft Rocket Materiel , United States Department of War , September 1944 [5]
- Technical Manual TM 9-394, 4.5-inch Rocket Materiel for Ground Use , United States Department of War , February 1945 [6]
- US rocket ordinance, development and use in world war II. , Washington, 1946, Joint Board on Scientific Information Policy [7]
- The Army almanac; a book of facts concerning the Army of the United States. , Washington, 1950, Armed Forces Information School, p. 128 [8]
- Constance McLaughlin Green , Harry C. Thomson, Peter C. Roots: The Ordnance Department: Planning Munitions for War , Washington, 1955, Office of the Chief of Military History, Department of the Army, [9]
- Frederick Ira Ordway, Ronald C. Wakeford: International missile and spacecraft guide , New York, 1960, McGraw-Hill Verlag, p. 116 [10]
- Mazzara, Andrew F .: Marine Corps Artillery Rockets: Back Through The Future , May 1987, Marine Corps Command and Staff College [11]
- Chris Bishop (Ed.): The Encyclopedia of Weapons of World War II , 2002, Sterling Publishing, ISBN 9781586637620 , [12]
- A. Bowdoin Van Riper: Rockets and Missiles: The Life Story of a Technology , Verlag Johns Hopkins University , 2007, ISBN 9780801887925 [13]
Web links
- US Ground / Air Launched Rockets at alternatewars.com [14]
- 4.5 inch Rocket in the National Air and Space Museum : [15]
- Air-Launched 4.5-Inch Rockets at designation-systems.net [16]
Individual evidence
- ↑ US rocket ordnance , 1946, pp. 23-24.
- ↑ Mark J. Reardon : Bazooka in: A History of Innovation: US Army Adaptation in War and Peace: US Army Adaptation in War and Peace , Center of Military History (US Army), 2010, ISBN 978-0-16-086722- 4 [1]
- ↑ US rocket ordnance , 1946, pp. 1-2, 23.
- ↑ West Point Association of Graduates on Leslie Skinner, based on the article Pioneers in Rocketry II by Leo A. Codd in ORDNANCE magazine, January – February 1959 ( online )
- ↑ Mark J. Reardon: Bazooka in: A History of Innovation: US Army Adaptation in War and Peace: US Army Adaptation in War and Peace , Center of Military History (US Army), 2010, ISBN 978-0-16-086722- 4 [2]
- ↑ US rocket ordnance , pp. 23-24.
- ↑ US rocket ordnance , 1946, pp. 23-24.
- ^ Green et al.: The Ordnance Department , 1955, p. 444.
- ↑ US rocket ordnance , 1946, pp. 23-24.
- ^ Bishop: The Encyclopedia of Weapons of World War II , 2002, p. 175.
- ^ Green et al.: The Ordnance Department , 1955, p. 444.
- ↑ US rocket ordnance , 1946, pp. 23-24.
- ^ Green et al: The Ordnance Department , 1955, pp. 444-445.
- ^ Green et al.: The Ordnance Department , 1955, pp. 435-437, 449.
- ^ Green et al.: The Ordnance Department , 1955, pp. 444-446.
- ↑ OS 9-69 , 1944, p. 75.
- ↑ Col. Leslie Skinner, Inventor of Bazooka in Evening Independent, November 4, 1978 ( Online )
- ↑ Green et al: The Ordnance Department , 1955, pp. 448-449.
- ↑ TM 9-394 1945, pp 110-111.
- ↑ US rocket ordnance , 1946, p. 24.
- ↑ OS 9-69 , 1944, pp. 53, 64.
- ↑ OS 9-69 , 1944, p. 70.
- ↑ OS 9-69 , 1944, p. 70.
- ↑ TM 9-394 , 1945, p. 103.
- ↑ OS 9-69 , 1944, p. 64.
- ↑ OS 9-69 , 1944, p. 53.
- ↑ OS 9-69 , 1944, pp. 63-64.
- ↑ TM 9-394 , 1945 S. 112th
- ↑ TM 9-394 , 1945, p. 103.
- ↑ TM 9-394 , 1945, p. 103.
- ↑ TM 9-394 , 1945, pp. 107, 110-111.
- ↑ OS 9-69 , 1944, p. 70.
- ↑ TM 9-394 , 1945 S. 107th
- ↑ OS 9-69 , 1944, p. 68.
- ↑ TM 9-394 , 1945, p. 45.
- ↑ OS 9-69 , 1944, p. 52.
- ↑ TM 9-395 p. 1.
- ↑ US rocket ordnance , 1946, p. 24.
- ^ Ordway, Wakeford: International missile and spacecraft guide , 1960, p. 116.
- ^ Green et al.: The Ordnance Department , 1955, pp. 446-448.
- ^ The Army almanac , 1950, p. 128.
- ^ Green et al: The Ordnance Department , 1955, p. 450.
- ^ Ordway, Wakeford: International missile and spacecraft guide , 1960, p. 116.
- ↑ US rocket ordnance , 1946, p. 45.
- ^ Van Riper: Rockets and Missiles , 2007, p. 44.
- ↑ Mazzara: Marine Corps Artillery Rockets , 1987, chapter 4.
- ↑ Steven J Zaloga: US Field Artillery of World War II , Osprey Publishing , 2011, ISBN 9781780962054 , p. 32 [3]
- ↑ Mazzara: Marine Corps Artillery Rockets , 1987, chapter 4.
- ^ Bishop: The Encyclopedia of Weapons of World War II , 2002, p. 175.
- ↑ Mazzara: Marine Corps Artillery Rockets , 1987, chapter 4.
- ^ Van Riper: Rockets and Missiles , 2007, p. 44.
- ↑ US rocket ordnance , 1946, p. 47.
- ^ Bishop: The Encyclopedia of Weapons of World War II , 2002, p. 177.
- ^ Bishop: The Encyclopedia of Weapons of World War II, 2002, p. 175.
- ^ Bishop: The Encyclopedia of Weapons of World War II , 2002, p. 175.
- ↑ OS 9-69, 1944, p. 75.
- ↑ TM 9-394 , 1945, pp. 15-16, 113-114.
