Junkers Ju 87 turned to the designs of Herman Pohlmann of Junkers and co-designer of the K 47, Karl Plauth. During the trials with the K 47 in 1932, the double vertical stabilisers were introduced to give the rear gunner a better field of fire. The main, and what was to be the most distinctive, feature of the Ju 87 was its double-spar inverted gull wings. After Plauth's death, Pohlmann continued the development of the Junkers dive bomber. The Ju A 48 registration D-ITOR, was originally fitted with a BMW 132 engine, producing 450 kW (600 hp). The machine was also fitted with
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