In September of 1939, German arms giant Krupp developed a new armored vehicle for the German Army Weapons Agency as a purpose-built, tracked, Self-Propelled Howitzer (SPH) platform with traversing turret. The tank was unique in being something of a "clean-sheet" SPH design, developed specifically for the artillery support role unlike other designs of the period which were generally hasty conversions and involved guns set within fixed superstructures.
Following testing of two vehicles, the design was accepted by the German Army under the designation of SfKfz 165/1 in January of 1940, these carrying the leFH 18/1 howitzer on the Panzer IV tank chassis. Power was from a single Maybach HL66 engine of 188 horsepower. While 200 were eventually ordered only ten achieved prototype stage as it was found that fairly good results could be obtained from modifying the surplus stock of outgoing Panzer II light tanks instead. Those SdKfz 165/1 tanks that did see the light of day are known to have been fielded in the East Front against the Soviets.
Work on a dedicated SPH continued into 1942 which, by now, allowed use of the new Hummel gun carrier chassis for the project. The traversing turret concept was carried over but a unique feature was built into it to fulfill an Army requirement - the turret (gun and all) could be dismounted from the hull and set as a fixed gun emplacement. The entire process was developed to be manual - no powered equipment needed, a hydraulic dismounting framework was fitted for this purpose. The main gun remained the leFH 18 light field howitzer and the turret design forced the Hummel's original center-engine placement to be shifted to the rear of the hull.
The reworked vehicle included a new glacis plate design. The crew numbered five and power was from a Maybach HL90 12-cylinder engine of 360 horsepower. Road speeds reached 45 kmh and range was out to 300 kilometers. The suspension was leaf-sprung. 87 total rounds were carried aboard for the 105mm gun.
The German Army took interest in the design - named the "Heuschrecke 10", or "Grasshopper" - and a pilot vehicle emerged for testing for October 1943. The hydraulic system was requested to have a manual failsafe as backup should it fail and authorities wanted a two-wheeled carried developed for accepting the turret/gun section as a towed weapon. The modifications were made and the revised vehicle emerged in May of 1944.
By this point, the program became a complex, expensive and somewhat novel concept that was no longer in need and the project was abandoned. The sole example was taken over by the advancing Americans who promptly shipped it back stateside for review and trials (at the Aberdeen Proving Ground).