18 minute read
8th AF BOMBING TACTICS
It was one of the largest and most important bombing missions of the war. Yet after extensive planning, target selection, bomb tonnage assignment and training, it would prove to be a dismal failure.
At 30 minutes past midnight on 6 June 1944, the first wave of three Allied air forces began bombing targets on the French coast of Normandy. First in were 100 Lancasters and Halifaxes of No 1 Group, RAF Bomber Command, dropping 534 tons of bombs on the gun emplacements on Hitler’s ‘Atlantic Wall’. As dawn broke it was the turn of the ‘Mighty Eighth’. In all, 1,361 heavy bombers were dispatched on the first mission on D-Day. Of those, 1,015 dropped their bombs. By 08.00hrs that morning, more than 3,200 Allied heavy and medium bombers had dropped in excess of 10,275 tons of ordnance on coastal targets.
Advertisement
Instead of lauding their success as part of the opening salvo of the greatest air, land, and sea invasion of the war, the Eighth Air Force stood back in silence. Even a decade after the war, the official histories of the Eighth sought to minimise its use of heavy bombers on that historic day. The first had to do with the ingrained culture of US bomber commanders. The role of the heavy bomber was strategic. Hitting German industrial targets was their primary mission and raison d’être. Supporting ground troops was the furthest thing from their minds. But more troubling was the fact that the D-Day bombing operation was a complete failure and the least effective Allied air operation of the entire war. Eighth Air Force ‘heavies’ failed to destroy any of their assigned targets. Sadly, more French civilians died in the raids than German soldiers.
After two-and-a-half years of daylight bombing, Eighth Air Force crews still faced a major problem. Their ability to find and hit their targets accurately was far from great. While daylight raids in good visibility produced acceptable results, the vast majority of missions were flown in less-than-ideal conditions. Obscured by cloud, smoke and constant anti-aircraft fire meant accuracy remained elusive. To get more bombs on target, the Eighth instituted several tactical changes and turned to technology to aid in its quest.
On 2 January 1942, the order activating the Eighth Air Force was signed by Maj Gen Henry ‘Hap’ Arnold, commander of the Army Air Forces. Arnold and many other prophets of the air believed air power, and specifically the strategic bombing of enemy industrial targets, could win a future war without the need for ground forces. The Eighth arrived in Britain with a core belief in purpose based on three articles of faith: tight formations of self-
defending bombers getting to and from the target without fighter escort, daylight ‘precision’ bombing with the aid of the infamous Norden bombsight, and the fact that the combination of the first two would lead to the destruction of Germany’s vital war industries, thus shortening or winning the war outright. The ability of bombers to defend themselves against fighter attack had already been disproven. It would take the Americans almost a year to come to the same conclusion.
The early bomber attacks starting in August 1942 were small and considered successful for the most part. The first raid, on 12 August, saw 12 B-17s dropping 45 600lb and nine 1,100lb bombs on the locomotive and rolling stock repair shops in Rouen, France. Visibility was unlimited and accuracy reasonably good. Elated by the mission, Eighth Air Force commander Gen Carl Spaatz declared, “We ruined Rouen”. It was far from the truth, but it seemed to confirm the AAF’s view of daylight precision bombing.
Eighth Air Force doctrine was dominated by defence. Tight formations of well-armed B-17s and B-24s with interlocking fields of fire would be sufficient to deal with any Luftwaffe fighter attack. As the Eighth Air Force penetrated deeper into Germany, Luftwaffe fighter attacks made it obvious that individual bombers could not spread out and make their own bomb run. As early as July 1943 formation bombing became standard operational procedure. Entire formations would now drop their bomb loads in unison when the lead ship dropped his. The resulting bomb pattern scattered
BELOW: Gen Carl Spaatz (second from left), the former Eighth Air Force commander who by this point was commander of US strategic air forces in Europe, and the then-current boss of the Eighth, Lt Gen Jimmy Doolittle (third from left), discuss the results of a bombing raid with airmen who have just returned from the mission. USAF
A fi ne example of a colourful ‘assembly ship’ is provided by this 458th BG B-24 from Horsham St Faith. USAF
Showing well a typical combat box formation, B-17Fs of the 305th BG’s 422nd BS en route to a raid against Villacoublay airfi eld south-west of Paris in August 1943.
NATIONAL ARCHIVES AND RECORDS ADMINISTRATION bombs all over the target, negating any hope of ‘precision’ daylight bombing.
To make formation bombing work, the Eighth Air Force directed that each squadron select a special ‘lead crew’, including the best bombardiers along with pilots and navigators. Lead crews were chosen for their ability to fl y smoothly and keep the formation together. ey would be responsible for fi nding the target and leading the combat formation on the bomb run. Once the release point was reached, the order to drop bombs was given. e rest of the formation dropped on this command. Only three other aeroplanes in each group carried bombsights — the wingman of the lead group and the leaders of the high and low squadrons. ese were the back-up crews in case the leader was shot down. e task of the other crews was to hold tight formation and release their bombs when the lead ship dropped. ‘Droppingon-the-leader’ reduced the other bombardiers to glorifi ed ‘togglers’, simply fl ipping a switch on cue. ❖
Crucial to the whole operation were the few seconds immediately before the lead crew released its bombs. is aircraft had to hold a steady course through fl ak, turbulence and fi ghter attack. Any manoeuvring, slips, skids or change in altitude would mean a loss of accuracy. VIII Bomber Command decided a mechanical autopilot could hold the precise position more accurately than the best pilot. Known as automatic fl ight control equipment (AFCE), it allowed the bombardier to control the aircraft on the bomb run with mechanical precision by synchronising the Norden bombsight with the aircraft. Inputs by the bombardier guided the machine more steadily and helped increase accuracy. e designated lead ships were soon equipped with AFCE.
Even with these improvements and tactical changes, just 25 per cent of their bombs dropped were hitting within 1,000ft of the aim point. “ e accuracy of our visual bombing, and probably to some extent of our radar bombing, has been substantially reduced by the necessity of bombing a large proportion of the time at extremely high altitudes”, said the Eighth Air Force’s Report on Bombing Accuracy for September to 31 December 1944.
The first problem faced by Eighth Air Force navigators was to find their assigned target area and individual factory or installation. Europe was dotted with many small towns and cities, some just miles apart, and identifying the right one was sometimes difficult. Weather and atmospheric conditions also led to inaccurate bombing. Industrial haze, especially over the Ruhr, could obscure the target. Cloud cover was another significant deterrent. And as the Eighth went deeper into Germany, the Germans began to ring their vital factories with smoke generators. The Luftwaffe relied on traditional camouflage and the building of decoy factories to draw bomber formations away from their intended targets.
Once in the target area, the bombardier had to first identify the specific factory or installation they were briefed to hit. This had to be done through anti-aircraft fire, haze on the ground or a smokescreen generated early enough to obscure the target. If it was covered in cloud they would have to divert to a secondary target, thus diminishing the destructive impact.
Smoke generators placed around vital targets proved highly effective and easy to use. The aforementioned report on bombing accuracy concluded, “on the basis of our past experience, from four to five times the force is required to achieve the required density of bombs on a target protected by smoke screen than would be necessary were there no smoke screen. No effective countermeasure has yet been found in this theater to neutralize the effect of smoke screens. Here the problem is essentially the same as that arising from our own bomb smoke. Some form of off-set bombing or some marking technique may provide the answer. Undoubtedly, however, considerable experimentation is necessary to develop such techniques.”
Bomber crews quickly learned that the weather over England and Europe was bad for flying, let alone finding and bombing a target from 30,000ft. During the winter, cloud cover over Germany averaged
between 60 and 80 per cent, and even in the summer months the unpredictable conditions impeded target identification and accuracy.
Another major and unforeseen problem was seeing the target after the first formation had dropped its bombs. Smoke, dust and debris were blasted into the air, often obscuring the target for the rest of the formation. Bombardiers simply aimed into the smoke and hoped for the best.
While Capt Lawrence S. Kuter from the US Army Air Corps Tactical School once said, “Anti-aircraft may be annoying but should be ignored”, this proved impossible in practice. German anti-aircraft defences had two important roles to play during the war. One was to shoot down enemy aircraft, and the other, more important one was to force bombers to drop their bombs sooner or from a higher altitude, thus reducing accuracy. Eighth Air Force commanders never considered German flak a problem until much later in the war.
As the Allied bomber offensive continued to grow, so the Luftwaffe responded with more guns and fighters. By the end of June 1943 there were 1,089 heavy flak batteries compared to 659 in January. Flak gun production had almost tripled between 1941 and 1943. The Germans also proved adept at modifying captured enemy flak guns. Between 1939 and 1944 the Luftwaffe managed to use 9,504 captured flak guns of all calibres and almost 14 million rounds of ammunition.
Flak forced the Eighth’s bombers to fly at between 23,000 and 30,000ft. As the altitude increased, flak accuracy decreased, but dropping a bomb from that height and hitting a target was extremely difficult. Once released, a bomb would encounter changes in wind direction and speed, temperature and air density — all factors that sent it off target. Even slight damage to a bomb fin would mean a miss instead of a hit. When the skies were clear, Eighth Air Force bombers sometimes missed their targets by miles. Bomber crews began to
The bombardier of 91st BG/401st BS B-17F
42-5132. NATIONAL ARCHIVES AND RECORDS ADMINISTRATION NOT A PRETTY SIGHT
The Norden bombsight was one of the most expensive military procurements of the 1930s and ’40s. Its development and production cost $1.5 billion, second only to the Manhattan Project. Originally commissioned by the US Navy, the Norden was a marvel of technology. Under clear skies and ideal conditions, well-trained bombardiers using the Norden could place their bombs withing 100ft of a target. However, this was from 5,000 to 8,000ft in altitude. Above 10,000ft, bombs fell between 200 and 400ft from the objective.
The combat conditions over Europe made the Norden bombsight even less accurate. Fighters, flak, weather and the need to fly at between 23,000 and 30,000ft caused half the bombs dropped to hit more than 1,000ft from the target. The Norden was best when used by single aircraft that could manoeuvre to line up on the target independently. In the European theatre of operations, this was never the case.
RIGHT: On 17 August 1943, a year to the day since VIII Bomber Command’s maiden raid, B-17s mounted a mission against ball bearing plants in Schweinfurt — over which these B-17Fs were photographed — and aircraft factories in Regensburg. It proved unsuccessful, demonstrating the need for better escort provision. USAF
joke that they were “killing sheep” or conducting “a major assault on German agriculture.”
By late 1943 the Eighth was fi nally starting to take the menace of German fl ak defences seriously. at October it introduced into service a gun-laying radar jammer codenamed ‘Carpet I’, and two months later it began using chaff , in the form of 12in aluminium foil strips. e lead bombers in each group would release bundles of chaff a few miles from the target in order to blind and confuse German radar. But while these methods reduced losses, still the bombers remained at high altitude. “[It] is apparent”, said the September-31 December 1944 Report on Bombing Accuracy, “that the development of eff ective means of neutralizing enemy anti-aircraft defenses to permit bombing at substantially lower altitudes would have the result of vastly increasing the effi ciency of our heavy bomber attacks”. Gen Henry ‘Hap’ Arnold later confessed, “We never conquered the German fl ak artillery.”
For the Eighth Air Force to achieve its goals, it needed clear skies, but it became apparent that Europe’s bad weather meant targets were often covered in cloud and impossible to fi nd. is meant vital objectives were not hit and exacerbated aircraft losses. e Eighth was not a fair-weather bombing force. Sorties needed to be generated, and bomb tonnage increased. In desperation, VIII Bomber Command looked to the
RAF for help during the late summer of 1943. British heavy bombers like the Halifax and Lancaster were already equipped with blind bombing and navigational aids. ese electronic and radar devices included Gee, a navigational aid using signals from ground stations, Oboe, a short-range precision navigational device, and H2S, an airborne ground mapping radar.
Because of short supply the RAF was reluctant to provide the Eighth with these new pieces of equipment. Another reason was the fear of them falling into German hands, even though RAF Bomber Command was losing dozens of heavy bombers every night over Germany. Trials with modifi ed B-17s began in August 1943.
At the start of the war the RAF relied on one method of navigation, dead-reckoning, aided by celestial or astro-navigation. In poor weather or at night, dead-reckoning was extremely limited. What was needed was some form of electronic aid for rapid position-fi xing. Tested in fl ight from August 1941, Gee consisted of a ‘master’ and two ‘slave’ stations which created a web-like system of radio beams over Germany. ese beams were picked up on a cathode ray tube in the navigator’s position. By plotting the signals from each station, the navigator could work out where the aircraft was to a high degree of accuracy.
Inevitably, Gee had its limitations. It was very useful as a navigation aid, getting aircraft to the general area of the target and home again, but could not provide any degree
of accuracy for bombing through cloud. With a view to precise targetmarking and bomb-aiming, Oboe was designed to not find a city but a precise spot in that city, such as a factory or rail yard at night or in heavy overcast. It involved two synchronised beams. Two UK-based stations, codenamed ‘Cat’ and ‘Mouse’, sent out a series of dots and dashes. The ‘Cat’ signal kept the aircraft on a track that would take it over the target; at the same time, ‘Mouse’ plotted the aircraft’s position, height and ground speed. The Oboe operators transmitted a ‘bomb release’ signal to the crew at the appropriate spot.
Whereas Gee’s range was 450 miles, Oboe’s was just 250 miles, good enough for attacks in the Ruhr but no further. It could also handle just one aircraft per frequency at a time. Such issues caused the Eighth Air Force to set its sights on H2S, a small ground-search radar mounted on the outside of the aircraft’s belly. The radar sent out a narrow beam which scanned the land below, creating an image on a cathode ray tube in the navigator’s position. The first B-17 equipped with H2S appeared in March 1943, and by October the Americans began to deploy their own improved version, called H2X. This was semi-retractable and was mounted in place of the belly turret on lead squadrons of B-17s and B-24s. ❖
With H2X the Eighth could now mount ‘blind bombing’ or area raids. But, unlike Gee and Oboe, it couldn’t afford real accuracy. The image produced on the radar tube took considerable skill and experience to interpret. A large city like Hamburg appeared as a white blob with no discernible detail to identify it. Where H2X performed well was when a city was close to a body of water, coastline or river. Those features created an image with excellent contrast and provided navigators and bombardiers with important information to fix their position before their bomb run. But while H2X allowed the Eighth Air Force to bomb through cloud, its accuracy wasn’t even close to visual bombing. H2X bombing yielded an average circular error of 1.1 miles under five-tenths’ cloud cover, or 2.5 miles under ten-tenths.
The Germans also knew how H2X worked and developed their own countermeasures against it.
Col Bud Peaslee, commanding officer of the Scouting Force (Experimental), with his P-51D 44-13283 Carolyn Ann.
NATIONAL ARCHIVES AND RECORDS ADMINISTRATION
EYES IN THE SKIES
Even with the addition of Gee, Oboe and H2X, the Eighth Air Force continued to find ways in which to improve its visual bombing methods. Weather was the most challenging and greatest obstacle to accurate visual bombing. It also presented other deadly hazards. Sending hundreds of fully loaded bombers into the head of unexpected thunderstorms with high turbulence and icing conditions caused formations to break up and the loss of many lives and aircraft.
The key to avoiding bad weather and cloud over the target was real-time intelligence. Having an aircraft out in front of the attacking force that could report on conditions ahead meant changes in course and altitude could be made and secondary targets assigned well in advance in case of inclement weather. While the primary function of the advance aircraft was to offer details of weather conditions, it could furthermore relay information on flak concentrations and incoming enemy fighters. The scout fighters and their escort also engaged enemy fighters when the opportunities presented themselves.
In December 1944 Col Bud J. Peaslee, commander of the 384th Bomb Group, suggested the idea of a scouting force to Lt Gen Jimmy Doolittle, now commander of the Eighth. Shortly afterwards, Peaslee began setting up shop. Recruiting ex-bomber pilots to fly the missions in P-51 Mustangs was the key to success, since they had better navigation and all-weather flying skills. Regular fighter pilots had little understanding of bombing operations and the requirements for a successful mission. In July 1944 the Scouting Force (Experimental) was formed as part of the 355th Fighter Group at Steeple Morden. The early missions were a great success and led to the formation of the 1st, 2nd and 3rd Scouting Forces, which operated until the end of the war.
assigned to the Leuna plant alone. While this could not in itself stop the attacks, the weapons did inflict heavy damage and kept the bombers at high altitude. Flak also intimidated bomber crews and played a crucial role in degrading accuracy.
Between May 1944 and April 1945, the Eighth mounted 233 raids on German fuel production. Because of the importance the Allies applied to the oil campaign, a study of the results was conducted after the war. The most significant finding was the difficulty in destroying an industrial target due to the poor accuracy of World War Two bombers. Multiple missions were required. The three main plants — Leuna, Ludwigshafen-Oppau and Zeitz — were hit with 30,000 tons of bombs, of which only 3,781 tons landed within the confines of the plants. And of the bombs that did hit their targets, 14.1 per cent of them were duds, according to German records.
The other problem the Eighth Air Force faced was the weight of its bombs. The 500lb bomb was the most numerous used by the Eighth, 1,365,387 being dropped on targets in Germany and occupied Europe. Short of a direct hit, they proved ineffective and made the task of destroying a set target costlier in terms of the missions needed to do the job and the number of aircraft damaged and lost.
After nearly three-and-a-half years of bombing, the Eighth Air Force’s dream of ‘precision’ daylight raids winning the war had been dashed. The inherent inaccuracy of a World War Two heavy bomber was too great for the existing technology to overcome. While the Eighth did hit and destroy select targets — many requiring repeated attacks — and played a critical role in securing victory in Europe, it came at a heavy price. As the Army Air Forces’ official history later acknowledged, the only way it was able to hit a target was by ‘drenching’ the entire area with bombs.
ABOVE: B-17Gs belonging to the 401st BG’s 613th BS at Deenethorpe. The weight of the bombs dropped by the Eighth was always inadequate.
KEY COLLECTION
BELOW: An H2X-equipped B-24 from the 449th
BG. NATIONAL ARCHIVES AND RECORDS ADMINISTRATION
