Jagdtiger
The Jagdtiger ("Hunting Tiger"; officially designated Panzerjäger Tiger Ausf. B) is a German casemate-type heavy tank destroyer ("Jagdpanzer") of World War II. It was built upon the slightly lengthened chassis of a Tiger II. Its ordnance inventory designation was Sd.Kfz. 186. The 71-tonne "Jagdtiger" was the heaviest armored fighting vehicle (AFV) used operationally by any participant nation of WWII and is the heaviest combat vehicle of any type to achieve series production during the conflict. The vehicle was armed with a 128 mm Pak 44 L/55 main gun which was capable of outranging and defeating any  tank or AFV fielded by the Allied forces. It saw brief service in small numbers from late 1944 up until the end of the war on both the Western and Eastern Front. Although 150 were ordered, only around eighty were produced. Due to an excessive weight and a significantly underpowered drivetrain system, the "Jagdtiger" was continuously plagued with various mobility and mechanical problems. At present, three "Jagdtigers" survive in different museums around the world. Development. With the success of the StuG III, Marder I, Marder II, and Marder III , the military leadership of Nazi Germany decided to use the chassis  of existing armored fighting vehicles as the basis for self-propelled guns (serving as assault guns and tank destroyers). German tank destroyers of World War II used fixed casemates instead of fully rotatable turrets to significantly reduce the cost, weight, and materials necessary for mounting large-caliber guns. In early 1942, a request was made by the Army General Staff to mount a 128 mm gun on a self-propelled armored chassis. Firing tests of the 128 mm gun showed it to have a high percentage of hits; smaller caliber guns, such as the ubiquitous 88 mm and the slightly  larger 105 mm, were also tested. By early 1943, a decision was made to install a 128 mm gun on either a Panther or Tiger I chassis as a heavy assault gun. The Panther chassis was considered unsuitable after a wooden mockup of the design was constructed. On 20 October 1943, another wooden mockup was constructed on a Tiger II heavy tank chassis, and presented to Hitler in East Prussia. Two prototypes were produced: One was a version fitted with the eight-roadwheel Porsche suspension system (serial number 305001) and another version was equipped with the Henschel nine-overlapping roadwheel  suspension system (serial number 305002), as used on the main-production Tiger IIs constructed by Henschel. They were completed in February 1944. It was originally designated as " VI" but was later renamed as the and received the Sd.Kfz. 186 designation as its inventory ordnance number. Design. The was a logical extension of the creation of designs from tank designs, such as the or the from the Panzer IV and Panther tanks respectively, with a fully armored and enclosed casemate-style fighting compartment. The used a boxy superstructure, with its sides integral with the hull sides, on top of a  lengthened Tiger II chassis. Unlike the , the 's casemate design did not extend its glacis plate upwards in one piece to the full height of the casemate's "roof" – it used a separate forward plate to form its casemate structure atop the hull roof, and mount its anti-tank gun. The resulting vehicle featured very heavy armor. It had armor on the front of the casemate and on the glacis plate. The main gun mount had a limited traverse of only 10 degrees; the entire vehicle had to be turned to aim outside that narrow field of fire. The suffered  from a variety of mechanical and technical problems due to its immense weight and under-powered engine. The vehicle had frequent breakdowns; ultimately more were lost to mechanical problems or lack of fuel than to enemy action. Production. One hundred and fifty were initially ordered but only between 70 and 85 were produced at the Nibelungenwerk at St. Valentin, from July 1944 to May 1945. Eleven of them, serial numbers 305001 and 305003 to 305012, were produced with the Porsche suspension (with eight road wheels per side); all the rest used the Henschel suspension with nine road wheels per side . Important parts such as the tub, superstructure and drive wheels were supplied by the . Details and production locations were known to the Allies through the resistance group around the later executed priest Heinrich Maier. Prisoners from the St. Valentin concentration camp were used to build the tank. Production figures vary depending on source and other factors such as if prototypes are included and if those made after VE day are included: approximately 48 from July 1944 to the end of December 1944; 36 from January to April 1945, serial numbers from 305001 to 305088. After serial number 305011 (September 1944 ), no Zimmerit anti-magnetic paste was factory applied. Combat history. Only two heavy anti-tank battalions (), numbered the 512th and 653rd, were equipped with , with the first vehicles reaching the units in September 1944. About 20% were lost in combat, with most destroyed by their own crews when abandoned, chiefly due to various mechanical breakdowns or the chronic lack of fuel in the final stages of the war. The gun used two-part ammunition, which meant that the main projectile and the cased propellant-charge were loaded into the gun-breech separately. Two loaders were tasked with this work, one  for each type. Tiger I tank ace Otto Carius commanded the second of three companies of in  512. His postwar memoir "Tigers in the Mud" provides a rare combat history of the 10 put under his command. He states that the were not utilized to their full potential due to several factors, among them that Allied air supremacy made it difficult to maneuver and the massive heavy gun needed to be re-calibrated from jarring after travelling off-road for even short distances. The vehicle was slow, having been equipped with the same engine as the already-underpowered Tiger I  and Tiger II, and the vehicle's transmissions and differentials broke down easily because the whole 72-tonne vehicle needed to rotate for the gun's traverse. The enormous 128 mm main-gun had to be locked down during the vehicle's maneuvers, otherwise its mounting-brackets would have worn out too much for accurate firing afterwards. As such, a crew-member had to exit the vehicle in combat and unlock the gun from its frontally mounted gun travel-lock before firing. Carius recorded that, in combat, a 128 mm projectile went through the walls of a house and destroyed  an American tank behind it. Insufficient training of vehicle crews and their poor morale during the last stage of the war were the biggest problems for crewmen under Carius's command. At the Ruhr Pocket, two commanders failed to attack an American armored column about away in broad daylight for fear of attracting an Allied air attack, even though the were well-camouflaged. Both vehicles broke down while hurriedly withdrawing through fear of the supposed air attack that did not materialize and one was then subsequently destroyed by its crew. To prevent such a disaster, at Siegen, Carius himself dug  in his command vehicle on high ground. An approaching American armored column avoided his prepared ambush because nearby German civilians warned them of it. Later, one of his vehicles fell into a bomb crater at night and was disabled while another was lost to a attack by friendly militia troops who had never seen a before and possibly misidentified it as an Allied armored vehicle. The first lost in combat was during the failed Operation Nordwind offensive in France in 1945. Although it was the most heavily armored vehicle to serve in World War II, this particular was lost not  to combat with other armored vehicles or aircraft but by American infantry using a bazooka, which at the time was considered an underpowered and ineffective weapon to counter such a massive vehicle. Near Unna, one climbed a hill to attack five American tanks 600 meters away, leading to two withdrawing and the other three opening fire. The took several hits but none of the American projectiles could penetrate the thick frontal armor of the vehicle's casemate. However, the inexperienced German commander then lost his nerve and turned around instead of backing down, thus exposing the thinner side armor, which  was eventually penetrated and all six crew members were lost. Carius wrote that it was useless when the crews were not trained or experienced enough to have the thick frontal armor facing the enemy at all times, if possible, in combat. When unable to escape the Ruhr Pocket, Carius ordered the guns of the remaining destroyed to prevent intact vehicles falling into Allied hands and then surrendered to American forces. The ten of the 2nd Company of  512 destroyed one American tank for one lost to combat, one lost to friendly fire, and eight others lost to mechanical breakdown or  destruction by their own crews to prevent capture by enemy forces. On 17 January 1945, two used by the XIV Corps engaged a bunker-line in support of assaulting infantry near Auenheim. On 18 January, they attacked four secure bunkers at a range of 1,000 meters. The armored cupola of one bunker burned out after two shots. A Sherman attacking in a counter-thrust fight was set afire by explosive shells. The total combat saw the usage by the two vehicles of 46 explosive shells and 10 anti-tank shells, with no losses to the . In April 1945,  512 saw  a great deal of action, especially on 9 April, where the 1st Company engaged an Allied column of Sherman tanks and trucks from hull-down positions and destroyed 11 tanks and over 30 unarmored or lightly armored targets, with some of the enemy tanks having been knocked out from a distance of more than 4,000 m. The combat unit only lost one in this incident, after Allied Republic P-47 Thunderbolt fighter-bombers appeared. During the next couple of days, the 1st Company destroyed a further five Sherman tanks before having to surrender to US troops at Iserlohn. Meanwhile, the 2nd  Company still fought on but with little results gained. On 15 April 1945, the unit surrendered at Schillerplatz in Iserlohn. Survivors. Three survive in museums around the world, one each in the US, the UK and Russia: Variants. Aside from the 11 early vehicles with a Porsche suspension, the only variant developed was the Sd.Kfz.185.