BK 3,7

BK 3,7 equipped ground attack aircraft were developed for tank hunting on the Eastern Front in an effort to blunt the massive numerical superiority of the Soviet T-34 tank as the war turned against Germany. The concept was rather rudimentary, suffered from poor accuracy, severe weight penalty making the craft vulnerable to fighters, and low ammunition capacity; but could be extremely effective when operated by a sufficiently skilled and practised ground-attack pilot, such as Hans-Ulrich Rudel in his BK 3,7 armed Junkers Ju 87G.

The heavy-calibre autocannon-armed series of Junkers Ju 88P twin-engined attack–bomber destroyer aircraft series used twin BK 3,7 cannon, mounted side-by-side in a conformal ventral fuselage gun pod, in its Ju 88P-2 and P-3 versions. The P-3 version only differed through the addition of extra defensive armour. As with other examples of the P-series, the Ju 88P-2 and P-3 were perceived as failures as anti-tank and bomber destroyer aircraft.

In contrast to the bombs delivered by dive bombing, when the BK 3,7 was used to attack the relatively thin armour of the top of the turret and the engine compartment armour of a tank, kills could be achieved with a relatively light and cheap armour-piercing projectile that could be carried in much greater quantities than bombs.

One of the two surviving Junkers Ju 87s is a G-2 model displayed at the Royal Air Force Museum Cosford; the wings have attachment points for BK 3,7 gun pods but it is not displayed with them fitted.

• BK 5 cannon: German 50 mm aircraft cannon
• BK 7,5 cannon: German 75 mm aircraft cannon
• COW 37 mm gun : earlier British equivalent

• Rapid Fire, Anthony G. Williams, Shrewsbury: Airlife Publishing Ltd., 2000. ISBN 1-84037-435-7.