Although American heavy bombers were unescorted by fighter aircraft in the opening months of the strategic bombing campaign, Luftwaffe interceptor pilots still had to contend with the massed firepower of the "combat box" formation. In attempting the most basic of attack approaches, from the rear or the "six o'clock" position, a German flier would not only be facing the twin .50 caliber guns mounted in the tail of his intended target, but potentially dozens of others from within the group of bombers.
Methods of Engaging the Combat Box
With the hazards associated with attacking the enemy from the tail position firmly in mind, Luftwaffe pilots logically shifted their focus to the lesser defended front of the formation. Upon interception, fighters would loiter outside of gunnery range, either abeam or behind, to estimate the speed and altitude of the bomber stream.
The German would then accelerate his aircraft to a point two miles ahead of the enemy and 1000 yards above before turning back towards his foe. With closing speeds approaching 500 mph, there was but a few scant seconds to line up a shot, squeeze off a short burst and break away to avoid a collision. A successful frontal attack required superior flying ability, skilled marksmanship and an iron will on the part of the Luftwaffe pilot.
Aside from the benefit of confronting fewer guns, the nose approach afforded an opportunity to fire directly in the bomber cockpits. A few well placed cannon rounds could at least disable, if not kill, an American flight crew. Later versions of both the B-17 and B-24 featured powered nose turrets to counter this threat.
The tail attack was not totally abandoned. Small numbers of less maneuverable, more rugged twin-engined aircraft such as the Messerschmitt Bf-110 and Junkers Ju-88 were fitted with a 37, 50 or even 75 mm cannon to permit engagement from outside the range of the heavy bombers tail guns. A single round from these weapons was capable of downing any Allied bomber. The appearance of Allied escort fighters later in the campaign chased these plodding aircraft from the skies.
Breaking the Combat Box
If the tightly maintained American formations could be forced to disperse, then the bombers could be dealt with individually. In July 1943, a new weapon was introduced to achieve that end.
Contained within simple launch tubes affixed to the outer wing sections of Luftwaffe interceptors, the 21 cm Werfergranate rocket propelled mortar shell was intended to be fired from distances beyond the range of bomber defenses. If the pilots aim was true, the unguided projectile's trajectory would place it within the combat box and its detonation would compel the bombers to scatter.
By autumn, Werfergranate armed Focke-Wulf Fw 190's were being used as the first wave of a German attack, to be followed up by standard interceptors.
The tactic was successfully employed during the Luftwaffe's defense of Schweinfurt on October 14, 1943, contributing to the destruction of 60 American bombers. The staggering loss of aircraft on that day resulted in the temporary suspension of unescorted daylight raids into Germany. When American bombers resumed daylight missions in early 1944, they were accompanied by escort fighters for the duration of their flight.
Attacking Bombers with Fighter Escort
With American fighter aircraft now providing round trip protection for the bomber formations, German interception tactics were once again modified.
Recalling prior experiences with the Royal Air Force during the Battle of Britain, Luftwaffe fighters were deployed in "Big Wings" to engage the enemy en masse. Modified Fw -190's with additional frontal and cockpit armor joined standard Bf-109's in formations of up to 100 aircraft, referred to as Sturmgruppen. The lighter, more agile Bf-109's would occupy the American escorts as waves of Fw-190's, in tightly spaced vee's of a dozen or more, assaulted the bombers.
The appearance of the Messerschmitt Me-262 jet fighter allowed circumvention of the defending escorts altogether. In a technique pioneered by Luftwaffe pilots of the Kommando Nowotny, a Me-262 would approach the rear of an American formation at top speed (nearly 600 mph), bypassing the fighter screen. The German jet would then dive to a position roughly a mile behind and a quarter mile below the bombers, pull up into a high-g climb to scrub off airspeed and level off when even with the enemy formation. Now inside the screen of escorts and with a relatively slow closing speed with the bombers, the interceptor pilot could select a target, trigger a short burst from his four 30 mm cannon, roll inverted and dive away.
Reference
Aggressors, Volume 3: Interceptor vs. Heavy Bomber, David A. Anderton, Zokeisha Publications, 1991
