 Complete the following phrase:  From August 1943, Bartels served with 11. Staffel of Jagdgeschwader 27 Afrika JG 2727th Fighter Wing. This Staffel was subordinated to the newly created IV. Gruppe of JG 27. The Gruppe had been formed in May 1943 at the Kalamaki Airfield in Athens, Greece under the command of Hauptmann Rudolf Sinner. 11. Staffel was commanded by Oberleutt Alfred Buk. On 17 July, IV. Gruppe moved to Tanagra Airfield. Bartels claimed his first aerial victories with JG 27 on 1 October. Flying from Gadurrà Airfield on Rhodes, he claimed two Douglas A-20 Havoc bombers, also known as Bostons, near of Kos. In early October, the United States Army Air Forces USAAF flew many missions in support of British forces fighting in the 