Junkers Ju 87 of 500 sorties per day and caused heavy losses among Soviet forces, losing an average of only one Stuka per day. The Battle of Stalingrad marked the high point in the fortunes of the Junkers Ju 87 Stuka. As the strength of the Soviet Air Forces grew, they gradually wrested control of the skies from the Luftwaffe. From this point onward, Stuka losses increased. The Stuka was also heavily involved in Operation Citadel, the Battle of Kursk. The Luftwaffe committed I, II, III./St.G 1 and III./StG 3 under the command of Luftflotte 6. I., II, III. of StGs 2 and
Junkers J 2 earlier J 1's structure. Junkers began wind tunnel and design work promptly upon receipt of the contract, and by the end of the spring of 1916 the first example was completed. The J 2 differed from the J 1 in having a cowling that almost entirely enclosed the engine, a rounded upper and lower fuselage section instead of the rectangular section of the J 1., and a narrower and deeper ventral radiator enclosure, and had a horizontal stabilizer planform shape that would become familiar on later, all-duralumin Junkers monoplane designs to be built during 1917-18. The "all-moving" rudder still possessed