On 18 June 1941, II. "Gruppe" moved from Beaumont-le-Roger to Abbeville-Drucat where it stayed for the next six months. From this point on, the "Gruppe" defended against the RAF Fighter Command "non-stop offensive" over France. In July 1941, while flying with the "Stab" (headquarters unit) of JG 2, Rudorffer claimed six aerial victories. This figure includes two Spitfires on 7 July, a Spitfire and a Hurricane on 9 July, one Spitfire on 10 and 11 July each. He then served with 6. "Staffel" of JG 2 and claimed fifteen further aerial victories by the end of 1941, taking his total to 41. Rudorffer was appointed "Staffelkapitän" (squadron leader) of 6. "Staffel" of JG 2 on 1 November 1941, thus succeeding "Oberleutnant" Frank Liesendahl who was transferred. In March 1942, II. "Gruppe" began converting to the Focke-Wulf Fw 190 A-2. Conversion training was done in a round-robin system, "Staffel" by "Staffel", at the Le Bourget Airfield near Paris. The conversion completed by end-April. From then on, the "Gruppe" was equipped with the Fw 190 A-2 and A-3 variant. In 1942, Rudorffer participated in Operation Cerberus (Channel Dash) and flew over the Allied landings at Dieppe in August 1942.