On 18 May 1942, Wilcke was transferred to "Jagdgeschwader" 3 "Udet" (JG 3—3rd Fighter Wing), named after the World War I fighter ace Ernst Udet. Operating on the Eastern Front, Wilcke became a "Geschwaderkommodore" of JG 3 "Udet" on 11 August, replacing "Oberst" (Colonel) Günther Lützow, who was posted to the staff of the "General der Jagdflieger" (General of Fighters) as Inspector of the Day Fighters on the Eastern Front. Operating from the Chuguyev Airfield, JG  3 "Udet" saw combat in the Kharkov area, present-day Kharkiv, during the Second Battle of Kharkov. On 26 June 1942, JG  3 "Udet" was assembled at Schtschigry on the southern sector of the Eastern Front for the upcoming summer offensive, supporting the Wehrmacht's advance towards Stalingrad. In the following months, JG  3 "Udet" was based at airfields at Gorshechnoye, Olkhovatka, Millerovo, Nowy-Cholan, Frolovo, Tuzov and Pitomnik.