Wednesday, February 23, 2011

Florida Wires: Man finds WWII era bazooka while tearing down shed
JACKSONVILLE, Fla. -- A man found a World War II era bazooka round while tearing down a shed and alerted the Jacksonville Sheriff's Office.

Bomb squad technicians examined the device Wednesday morning and determined it was not in danger of exploding.

Lt. Andy Morgan says the device, which was discovered in the city's San Marco neighborhood, appears to have been inert for some time.

I must say it never occurred to me that a bazooka could explode, any more than a rifle could explode. Now, rifle bullets or bazooka shells, that's another story.

Either a poorly written article and they meant to say that there was no shell in the bazooka, or the writer and the bomb squad folks don't know the first things about bazookas.

From Wikipedia
Bazooka is the common name for a man-portable recoilless rocket antitank weapon, widely fielded by the US Army. Also referred to as the "Stovepipe", the innovative bazooka was amongst the first-generation of rocket propelled anti-tank weapons used in infantry combat. Featuring a solid rocket motor for propulsion, it allowed for high explosive (HE) and high-explosive anti-tank (HEAT) warheads to be delivered against armored vehicles, machine gun nests, and fortified bunkers at ranges beyond that of a standard thrown grenade or mine. The universally-applied nickname arose from the M9 variant's vague resemblance to the tubular musical instrument of the same name invented and popularized in the 1930s by US comedian Bob Burns. An alternative etymology ascribed the name to the unique sound the weapon made when fired.

During World War II, German armed forces captured several bazookas in early North African encounters and soon reverse engineered their own version, increasing the warhead diameter to 8.8 cm (amongst other minor changes) and widely issuing it as the Raketenpanzerbüchse "Panzerschreck" ("Tank frightener").

Due to the novelty and easy recognition of the name, the term "bazooka" continues to be used informally as a genericized term to refer to any shoulder-launched missile weapon.

The development of the bazooka involved the development of two specific lines of technology: the rocket-powered (recoilless) weapon, and the shaped-charge warhead. It was also designed for easy maneuverability and access.

World War II
The Rocket-Powered Recoilless Weapon was the brainchild of Dr. Robert H. Goddard as a side project (under Army contract) of his work on rocket propulsion. Goddard, during his tenure at Clark University, and while working at Worcester Polytechnic Institute's magnetics lab and Mount Wilson Observatory (for security reasons), designed a tube-fired rocket for military use during World War I. He and his co-worker, Dr. Clarence Hickman, successfully demonstrated his rocket to the U.S. Army Signal Corps at Aberdeen Proving Ground, Maryland, on November 6, 1918, but as the Compiègne Armistice was signed only five days later, further development was discontinued. The delay in the development of the bazooka was as a result of Goddard's serious bout with tuberculosis. Goddard continued to be a part-time consultant to the U.S. Government at Indian Head, Maryland, until 1923, but soon turned his focus to other projects involving rocket propulsion.

The shaped charge
The development of the explosive shaped charge dates back to the work of American physicist Charles Edward Munroe, who did the first practical work on the subject in 1880. This work was augmented in the 1930s by Henry Mohaupt, a Swiss immigrant who worked on shaped-charge explosives design for the US War Department (the predecessor of the Department of Defense).

Mohaupt developed a shaped charge hand grenade for anti-tank use, effective at defeating up to 60 mm (2.4 in) of vehicle armor, thus by far the best such weapon in the world at the time. The grenade was standardized as the M10. However, the M10 grenade weighed 3.5 lb (1.6 kg), was difficult to throw by hand, and too heavy to be launched as a rifle grenade. The only practical way to use the weapon was for an infantryman to place it directly on the tank, an unlikely means of delivery in most combat situations. A smaller, less powerful version of the M10, the M9, was then developed, which could be fired from a rifle. This resulted in the creation of a series of rifle grenade launchers, the M1 (Springfield M1903), M2 (Enfield M1917), and the M7 and M8 (M1 Garand). However, a truly capable anti-tank weapon had yet to be found, and following the lead of other countries at the time, the U.S. Army prepared to evaluate competing designs for a large and powerful anti-tank rifle.

The combination of rocket motor and shaped charge warhead would put paid to Army development of light antitank guns.

Rocket-borne Shaped Charge Weapons Development
In 1942, U.S. Army Colonel Leslie Skinner received the M10 shaped-charge grenade which was capable of stopping German tanks. He tasked Lieutenant Edward Uhl with creating a delivery system for the grenade. Uhl created a small rocket, but needed to protect the firer from the rocket exhaust and aim the weapon. According to Uhl,

"I was walking by this scrap pile, and there was a tube that ... happened to be the same size as the grenade that we were turning into a rocket. I said, That's the answer! Put the tube on a soldier's shoulder with the rocket inside, and away it goes."

Uhl developed the rocket launcher and is known as father of the Bazooka.

Development of the M1 prototype took place in Corcoran Hall at The George Washington University in Washington, D.C. with the help of Clarence Hickman who had worked for Goddard. The M1 consisted of a sheet metal tube with a simple wooden stock, hand grips, and sights (replaced by metal in production models), into which the 60.07 mm-diameter (officially designated "M6, 2.36-inch" to avoid confusion with rounds for the 60 mm mortar) rocket grenades were inserted at the rear with trailing electrical leads. The cast steel warhead contained 1.6 lb of Pentolite high explosive. A two-cell dry battery in the wood shoulder rest provided a charge to ignite the rocket when the trigger was pulled; the wires sticking out the back of the round having been connected to two contacts by the assisting loader.

Although the weapon had some reliability and accuracy problems, Ordnance officials were greatly pleased with the penetrative effect of the new M1, which blew the turret off a tank during field trials.The weapon's M6 rocket warhead was capable of penetrating roughly 4.5 inches (112 mm) of armor plate.As a result, the War Department cancelled all plans for anti-tank rifles and in 1942 adopted the M1 rocket launcher and its M6 rocket as standard. The M1 rocket launcher was the first type to see combat use.

By late 1942, the improved Rocket Launcher, M1A1 was introduced. The forward hand grip was deleted, and the design simplified. The production M1A1 was 54 inches (1.37 m) long and weighed only 12.75 pounds (5.8 kg).

The ammunition for the original M1 launcher was the M6, which was notoriously unreliable. The M6 was improved and designated M6A1, and the new ammunition was issued with the improved M1A1 launcher. After the M6, several alternative warheads were introduced. The 2.36-Inch Smoke Rocket M10 and its improved subvariants (M10A1, M10A2, M10A4) used the rocket motor and fin assembly of the M6A1, but replaced the anti-tank warhead with a white phosphorus (WP) smoke head. WP smoke not only acts as a visible screen, but its burning particles can cause burns on human skin. The M10 was therefore used to mark targets, to blind enemy gunners or vehicle drivers, or to drive troops out of bunkers and dugouts.

The 2.36-Inch Incendiary Rocket T31 was an M10 variant with an incendiary warhead designed to ignite fires in enemy-held structures and unarmored vehicles, or to destroy combustible supplies, ammunition, and materiel.

The original M1A1 rocket launcher was equipped with a simple hinged rear sight and fixed front sights, and used a launch tube without reinforcements. During the war, the M1A1 received a number of running modifications. The battery specification was changed to a larger, standard battery cell size, resulting in complaints of batteries getting stuck in the wood shoulder rest (the compartment was later reamed out to accommodate the larger cells).

This was followed by a new aperture rear sight and a front rectangular "frame" sight positioned at the muzzle. The vertical sides of the frame sight were inscribed with graduations of 100, 200, and 300 yards. On later models, the iron sights were at first replaced by a plastic optical ring sight, which proved unsatisfactory in service, frequently turning opaque after a few days' exposure to sunlight. Later iron sights were hinged to fold against the tube when not in use, and were protected by a cover. The launcher also had an adjustable range scale that provided graduations from 50 to 700 yards (46 to 640 meters) in 50-yard (46 m) increments. An additional strap iron shoulder brace was fitted to the launcher, along with various types of blast deflectors.

The bazooka required special care when used in tropical or arctic climates or in severe dust or sand conditions. Rockets were not to be fired at temperatures below zero F or above 120 F.

Field experience induced changes
In 1943, field reports of rockets sticking and prematurely detonating in M1A1 launch tubes were received by Army Ordnance at Ogden Arsenal and other production facilities. At the U.S. Army's Aberdeen Testing Grounds, various metal collars and wire wrapping were used on the sheet metal launch tube in an effort to reinforce it. However, reports of premature detonation continued until the development of bore slug test gauges to ensure that the rocket did not catch inside the launch tube.

The original M6 and M6A1 rockets used in the M1 and M1A1 launchers had a pointed nose, which was found to cause deflection from the target at low impact angles. In late 1943, another 2.36-in rocket type was adopted, the M6A3, for use with the newly standardized M9 rocket launcher.[6] The M6A3 was 19.4 inches (493 mm) long, and weighed 3.38 lb (1.53 kg). It had a blunted nose to improve target effect at low angles, and a new circular fin assembly to improve flight stability. The M6A3 was capable of penetrating five inches (125 mm) of armor plate.

Battery problems in the early bazookas eventually resulted in replacement of the battery-powered ignition system with a magneto sparker system operated through the trigger. A trigger safety was incorporated into the design that isolated the magneto, preventing misfires that could occur when the trigger was released and the stored charge prematurely fired the rocket.

The final major change was the division of the launch tube into two discrete sections, with bayonet-joint attachments. This was done to make the weapon more convenient to carry, particularly for use by airborne forces. The final two-piece launcher was standardized as the M9A1. However, the long list of incorporated modifications increased the launcher's tube length to 61 inches (1.55 m), with an overall empty weight of 14.3 lb (6.5 kg). From its original conception as a relatively light, handy, and disposable weapon, the final M9A1 launcher had become a heavy, clumsy, and relatively complex piece of equipment.

In October 1944, after receiving reports of inadequate combat effect of the M1A1 and M9 launchers and their M6A1 rockets, and after examining captured examples of the German 8.8 cm RPzB 43 and RPzB 54 Panzerschreck, the U.S. Ordnance Corps began development on a new, more powerful anti-tank rocket launcher, the 3.5-inch M20. However, the weapon's design was not completed until after the war.

In 1945, the U.S. Army's Chemical Warfare Service standardized improved chemical warfare rockets intended for the new M9 and M9A1 launchers, adopting the M26 Gas Rocket, a cyanogen chloride (CK)-filled warhead for the 2.36-in rocket launcher. CK, a deadly blood agent, was capable of breaking down the protective chemical barriers in some gas masks, and was seen as an effective agent against Japanese forces (particularly those hiding in caves or bunkers), whose gas masks lacked the impregnants that would provide protection against the chemical reaction of CK. While stockpiled in U.S. inventory, the CK rocket was never deployed or issued to combat personnel.

Even though in late 1942 the general American public became aware of the bazooka in small articles in the monthly magazines Popular Mechanics and Popular Science it was not until early 1945 that they learned in a very large and detailed article in Popular Science the true secret of the bazooka's warhead. The US War Department had decided that it was only a matter of time before both Germany and Japan were defeated and the secrets of shape charges were already well known by its enemies.

Operational use
World War IISecretly introduced via the Russian front and in November 1942 during Operation Torch, early production versions of the M1 launcher and M6 rocket were hastily supplied to some of the U.S. invasion forces during the landings in North Africa. On the night before the landings, Gen. Dwight D. Eisenhower was shocked to discover from a subordinate that none of his troops had received any instruction in the use of the bazooka.

Initially supplied with the highly unreliable M6 rocket and without training, the M1 did not play a significant armed role in combat in the North African fighting,but did provide a German intelligence coup when some were captured by the Germans in early encounters with inexperienced U.S. troops. A U.S. general visiting the Tunisian front in 1943 after the close of combat operations could not find any soldiers who could report that the weapon had actually stopped an enemy tank. Further issue of the bazooka was suspended in May 1943.

During the Allied invasion of Sicily, small numbers of the M1A1 bazooka (using an improved rocket, the M6A1) were used in combat by U.S. forces. The M1A1 accounted for four medium German tanks and a heavy Tiger I, with the latter being knocked out by a lucky hit through the driver's vision slot.A major disadvantage to the bazooka was the large backblast and smoke trail, which gave away the position of the shooter. Moreover, the bazooka fire team often had to expose their bodies in order to obtain a clear field of fire against an armored target. Casualties among bazooka team members were extremely high during the war, and assignment to such duty in the face of German counterfire was typically regarded by other platoon members as not only highly dangerous, but nearly suicidal.

When the existence of the bazooka was revealed to the American public official press releases for the first two years stated that it "packed the wallop of a 155mm cannon". Something that was obviously war time disinformation, but it was widely accepted by the American public

In late 1942, numbers of early-production American M1 bazookas were captured by German troops from Russian forces who had been given quantities of the bazooka under Lend-Lease as well as during the Operation Torch invasions in the North African Campaign.

The Germans promptly developed their own version of the weapon, increasing the diameter of the warhead from 60 mm to 88 mm (2.4 to 3.5 in). In German service, the bazooka was popularly known as the Panzerschreck. The German weapon, with its larger, more powerful warhead, had significantly greater armor penetration; ironically, calls for a larger-diameter warhead had also been raised by some ordnance officers during U.S. trials of the M1, but were rejected. After participating in an armor penetration test involving a German Panther tank using both the RPzB 54 Panzerschreck and the U.S. M9 bazooka, Corporal Donald E. Lewis of the U.S. Army informed his superiors that the Panzerschreck was "far superior to the American bazooka" ...

“ I was so favorably impressed [by the Panzerschreck] I was ready to take after the Krauts with their own weapon.”

In France, a Major Charlie Carpenter mounted a battery of three bazookas under each wing of his L-5 Sentinel aircraft to attack German tanks and claimed to have destroyed fourteen.

Despite the introduction of the M9 bazooka with its more powerful rocket—the M6A3—in late 1943, reports of the weapon's effectiveness against enemy armor decreased alarmingly in the latter stages of World War II, as new German tanks with thicker and better-designed cast armor plate and armor skirts/spaced armor were introduced. This development forced bazooka operators to target less well-protected areas of the vehicle, such as the tracks, drive sprockets, bogey wheels, or rear engine compartment. In a letter dated May 20, 1944, Gen. George S. Patton stated to a colleague that "the purpose of the bazooka is not to hunt tanks offensively, but to be used as a last resort in keeping tanks from overrunning infantry. To insure this, the range should be held to around 30 yards."

In the Pacific campaign, as in North Africa, the original bazookas sent to combat often had reliability issues. The battery-operated firing circuit was easily damaged during rough handling, and the rocket motors often failed because of high temperatures and exposure to moisture, salt air, or humidity. With the introduction of the M1A1 and its more reliable rocket ammunition, the bazooka was effective against some fixed Japanese infantry emplacements such as small concrete bunkers and pill boxes. Against coconut and sand emplacements, the weapon was not always effective, as these softer structures proved too resilient, often absorbing the warhead's impact sufficiently to prevent detonation of the explosive charge. Later in the Pacific war, most infantry and marine units often used the M2 flamethrower to overcome such obstacles.

In the few instances in the Pacific where the bazooka was used against tanks and armored vehicles, the rocket's warhead easily penetrated the thin armor plate used by the Japanese and destroyed the vehicle.[27] Overall, the M1A1, M9, and M9A1 rocket launchers were viewed as useful and effective weapons during World War II, though they had been primarily employed against enemy emplacements and fixed fortifications, not as anti-tank weapons.[20] General Dwight Eisenhower later described it as one of the four "Tools of Victory" which won World War II for the Allies (together with the atom bomb, Jeep and the C-47 Skytrain transport aircraft).

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