Junkers Ju 87 armoured protection of the Ilyushin Il-2 "Sturmovik" - a feature pioneered by the 1916-17 origin Junkers J.I all-metal sesquiplane of World War I Imperial Germany's Luftstreitkräfte - was copied to protect the crew from ground fire now that the Ju 87 would be required to conduct low level attacks. Hans-Ulrich Rudel, a Stuka ace, had suggested using two 37 mm (1.46 in) Flak 18 guns, each one in a self-contained under-wing gun pod, as the "Bordkanone BK 3,7", after achieving success against Soviet tanks with the 20 mm MG 151/20 cannon. These gun pods were fitted to a Ju 87
Junkers T 29 L1a inline engine cowled with its cylinder heads slightly exposed. Pilot and passenger sat side by side over the wing in a cockpit open apart from a longitudinal arch over their heads to protect them like a roll bar, set perpendicularly to the similar cross-fuselage device only used directly "behind" the cockpit on the Junkers J 2, the Junkers J 7 experimental duralumin-structure monoplane and production Junkers D.I fighter of the late World War I years. This unusual feature reminded observers of a handle and earned the J 29 the nickname "Bügeleisen" (en: flat iron). The fuselage tapered to the