 Complete the following phrase:  On 1 August 1943, Sturm was appointed acting Staffelkapitän squadron leader of 4. Staffel 4th squadron of JG 52. He replaced Leutt Helmut Lipfert in this capacity who was transferred to the 6. Staffel 4th squadron of JG 52. Sturm later officially became the Staffelkapitän of 4. Staffel on 1 September, succeeding Hauptmann Gerhard Barkhorn who was given command of II. Gruppe. That day, the Gruppe moved to an airfield at Karlivka where they fought in the aftermath of the BelgorodKharkov offensive operation, also referred to as the fourth Battle of Kharkov. Here, Sturm claimed his first aerial victory as Staffelkapitän when he shot down a La-5 fighter. In November, the Red Army launched the 