from en.wikipedia.org
TIME LIFE " - The Battle of Britain issue
Second World War - Martin Gilbert
By the beginning of 1941 , British night air defences were in a poor state. Few anti-aircraft guns had fire-control systems, and the underpowered searchlights were usually ineffective against aircraft at altitudes above 12,000 ft (3,700 m). In July 1940, only 1,200 heavy and 549 light guns were deployed in the whole of Britain. Of the “heavies”, some 200 were of the obsolescent 3 in (76 mm) type ; the remainder were the effective 4.5 in (110 mm and 3.7 in (94 mm) guns , with a theoretical “ceiling”’ of over 30,000 ft (9,100 m) but a practical limit of 25,000 ft (7,600 m) because the predictor in use could not accept greater heights. The light guns, about half of which were of the excellent Bofors 40 mm , dealt with aircraft only up to 6,000 ft (1,800 m). Although the use of the guns improved civilian morale, with the knowledge the German bomber crews were facing the barrage, it is now believed that the anti-aircraft guns achieved little and in fact the falling shell fragments caused more British casualties on the ground.
Few fighter aircraft were able to operate at night. Ground-based radar was limited, and airborne radar and RAF night fighters were generally ineffective. RAF day fighters were converting to night operations and the interim Bristol Blenheim night fighter conversion of the light bomber was being replaced by the powerful Bristol Beaufighter, but this was only available in very small numbers. By the second month of the Blitz the defences were not performing well. London’s defences were rapidly reorganised by General Pile, the Commander-in-Chief of Anti-Aircraft Command. The difference this made to the effectiveness of air defences is questionable. The British were still one-third below the establishment of heavy anti-aircraft artillery AAA (or ack-ack) in May 1941, with only 2,631 weapons available. Dowding had to rely on night fighters. From 1940 to 1941, the most successful night-fighter was the Boulton Paul Defiant; its four squadrons shot down more enemy aircraft than any other type. AA defences improved by better use of radar and searchlights. Over several months, the 20,000 shells spent per raider shot down in September 1940, was reduced to 4,087 in January 1941 and to 2,963 shells in February 1941.
Airborne Interception radar (AI) was unreliable. The heavy fighting in the Battle of Britain had eaten up most of Fighter Command’s resources, so there was little investment in night fighting. Bombers were flown with airborne search lights out of desperation but to little avail. Of greater potential was the GL (Gunlaying) radar and searchlights with fighter direction from RAF fighter control rooms to begin a GCI system (Ground Control-led Interception) under Group-level control No. 10 Group RAF, No. 11 Group RAF and No. 12 Group RAF.
Whitehall’s disquiet at the failures of the RAF led to the replacement of Dowding (who was already due for retirement) with Sholto Douglas on 25 November. Douglas set about introducing more squadrons and dispersing the few GL sets to create a carpet effect in the southern counties. Still, in February 1941, there remained only seven squadrons with 87 pilots, under half the required strength. The GL carpet was supported by six GCI sets controlling radar-equipped night-fighters. By the height of the Blitz, they were becoming more successful. The number of contacts and combats rose in 1941, from 44 and two in 48 sorties in January 1941, to 204 and 74 in May (643 sorties). But even in May, 67 per cent of the sorties were visual cat’s-eye missions. Curiously, while 43 per cent of the contacts in May 1941 were by visual sightings, they accounted for 61 percent of the combats. Yet when compared with Luftwaffe daylight operations, there was a sharp decline in German losses to one per cent. If a vigilant bomber crew could spot the fighter first, they had a decent chance of evading it.
Nevertheless, it was radar that proved to be the critical weapon in the night battles over Britain from this point onward. Dowding had introduced the concept of airborne radar and encouraged its usage. Eventually it would become a success. On the night of 22/23 July 1940, Flying Officer Cyril Ashfield (pilot), Pilot Officer Geoffrey Morris (Observer) and Flight Sergeant Reginald Leyland (Air Intercept radar operator) of the Fighter Interception Unit became the first pilot and crew to intercept and destroy an enemy aircraft using on-board radar to guide them to a visual interception, when their AI night fighter brought down a Do 17 off Sussex. On 19 November 1940 the famous RAF night fighter ace John Cunningham] shot down a Ju 88 bomber using airborne radar, just as Dowding had predicted. By mid-November, nine squadrons were available, but only one was equipped with Beaufighters No. 219 Squadron RAF at RAF Kenley airfield. By 16 February 1941, this had grown to 12; with five equipped, or partially equipped with Beaufighters spread over five Group.
Not all of the Luftwaffe effort was made against inland cities. Port cities were also attacked to try to disrupt trade and sea communications. In January, Swansea was bombed four times, very heavily. On 17 January around 100 bombers dropped a high concentration of incendiaries, some 32,000 in all. The main damage was inflicted on the commercial and domestic areas. Four days later 230 tons was dropped including 60,000 incendiaries. In Portsmouth , Southsea and Gosport waves of 150 bombers destroyed vast swaths of the city with 40,000 incendiaries. Warehouses, rail lines and houses were destroyed and damaged, but the docks were largely untouched. In January and February 1941, Luftwaffe bombers serviceability rates declined, until just 551 of 1,214 bombers were combat worthy. Seven major and eight heavy attacks were flown, but the weather made it difficult to keep up the pressure. Still, at Southampton , attacks were so effective morale did give way briefly with civilian authorities leading people en masse out of the city.
Although official German air doctrine did target civilian morale, it did not espouse the attacking of civilians directly. It hoped to destroy morale by destroying the enemy’s factories and public utilities as well as its food stocks (by attacking shipping). Nevertheless, its official opposition to attacks on civilians became an increasingly moot point when large-scale raids were conducted in November and December 1940. Although not encouraged by official policy, the use of mines and incendiaries, for tactical expediency, came close to indiscriminate bombing. Locating targets in skies obscured by industrial haze meant the target area needed to be illuminated and hit “without regard for the civilian population”.Special units, such as KGr 100, became the Beleuchtergruppe (Firelighter Group), which used incendiaries and high explosive to mark the target area. The tactic was expanded into Feuerleitung (Blaze Control) with the creation of Brandbombenfelder (Incendiary Fields) to mark targets. These were marked out by parachute flares. Then bombers carrying SC 1000 (1,000 kg (2,205 lb), SC 1400 (1,400 kg (3,086 lb), and SC 1800 (1,800 kg (3,968 lb) “Satan” bombs were used to level streets and residential areas. By December, the SC 2500 (2,500 kg (5,512 lb)) “Max” bomb was used.
These decisions, apparently taken at the Luftflotte or Fliegerkorps level, meant attacks on individual targets were gradually replaced by what was, for all intents and purposes, an unrestricted area attack or Terrorangriff (Terror Attack). Part of the reason for this was inaccuracy of navigation. The effectiveness of British countermeasures against Knickebein , which was designed to avoid area attacks, forced the Luftwaffe to resort to these methods. The shift from precision bombing to area attack is indicated in the tactical methods and weapons dropped. KGr 100 increased its use of incendiaries from 13–28 percent. By December, this had increased to 92 percent. Use of incendiaries, which were inherently inaccurate, indicated much less care was taken to avoid civilian property close to industrial sites. Other units ceased using parachute flares and opted for explosive target markers. Captured German air crews also indicated the homes of industrial workers were deliberately targeted.
In 1941, the Luftwaffe shifted strategy again. Admiral Erich Raeder —commander-in-chief of the Kriegsmarine —had long argued the Luftwaffe should support the German submarine force ( U-Bootwaffe ) in the Battle of the Atlantic by attacking shipping in the Atlantic Ocean and attacking British ports. Eventually, he convinced Hitler of the need to attack British port facilities. At Raeder’s prompting, Hitler correctly noted that the greatest damage to the British war economy had been done through the destruction of merchant shipping by submarines and air attacks by small numbers of Focke-Wulf Fw 200 naval aircraft and ordered the German air arm to focus its efforts against British convoys. This meant that British coastal centres and shipping at sea west of Ireland were the prime targets.
Hitler’s interest in this strategy forced Göring and Jeschonnek to review the air war against Britain in January 1941. This led to Göring and Jeschonnek agreeing to Hitler’s Directive 23, Directions for operations against the British War Economy , which was published on 6 February 1941 and gave aerial interdiction of British imports by sea top priority. This strategy had been recognised before the war, but Operation Eagle Attack and the following Battle of Britain had got in the way of striking at Britain’s sea communications and diverted German air strength to the campaign against the RAF and its supporting structures. The OKL had always regarded the interdiction of sea communications of less importance than bombing land-based aircraft industries.
Directive 23 was the only concession made by Göring to the Kriegsmarine over the strategic bombing strategy of the Luftwaffe against Britain. Thereafter, he would refuse to make available any air units to destroy British dockyards, ports, port facilities, or shipping in dock or at sea, lest Kriegsmarine gain control of more Luftwaffe units. Raeder’s successor—Admiral Karl Dönitz—would—on the intervention of Hitler—gain control of one unit KG 40 (two Focke Wulf 200 squadrons to strike British shipping at Atlantic) , but Göring would soon regain it. Göring’s lack of co-operation was detrimental to the one air strategy with potentially decisive strategic effect on Britain. Instead, he wasted aircraft of Fliegerführer Atlantik (Flying Command Atlantic) on bombing mainland Britain instead of attacks against convoys. For Göring, his prestige had been damaged by the defeat in the Battle of Britain, and he wanted to regain it by subduing Britain by air power alone. He was always reluctant to co-operate with Raeder.
Even so, the decision by the OKL to support the strategy in Directive 23 was instigated by two considerations, both of which had little to do with wanting to destroy Britain’s sea communications in conjunction with the Kriegsmarine . First, the difficulty in estimating the impact of bombing upon war production was becoming apparent, and second, the conclusion British morale was unlikely to break led the OKL to adopt the naval option. The indifference displayed by the OKL to Directive 23 was perhaps best demonstrated in operational directives which diluted its effect. They emphasised the core strategic interest was attacking ports but they insisted in maintaining pressure, or diverting strength, onto industries building aircraft, anti-aircraft guns, and explosives. Other targets would be considered if the primary ones could not be attacked because of weather conditions.
A further line in the directive stressed the need to inflict the heaviest losses possible, but also to intensify the air war in order to create the impression an amphibious assault on Britain was planned for 1941. However, meteorological conditions over Britain were not favourable for flying and prevented an escalation in air operations. Airfields became water-logged and the 18 Kampfgruppen (bomber groups) of the Luftwaffe 's [Kampfgeschwadern] (bomber wings) were relocated to Germany for rest and re-equipment.
From the German point of view, March 1941 saw an improvement. The Luftwaffe flew 4,000 sorties that month, including 12 major and three heavy attacks. The electronic war intensified but the Luftwaffe flew major inland missions only on moonlit nights. Ports were easier to find and made better targets. To confuse the British, radio silence was observed until the bombs fell. X- and Y- Gerät beams were placed over false targets and switched only at the last minute. Rapid frequency changes were introduced for X- Gerät , whose wider band of frequencies and greater tactical flexibility ensured it remained effective at a time when British selective jamming was degrading the effectiveness of Y- Gerät.
By now, the imminent threat of invasion had all but passed as the Luftwaffe had failed to gain the prerequisite air superiority. The aerial bombing was now principally aimed at the destruction of industrial targets, but also continued with the objective of breaking the morale of the civilian population. The attacks were focused against western ports in March. These attacks produced some breaks in morale, with civil leaders fleeing the cities before the offensive reached its height. But the Luftwaffe 's effort eased in the last 10 attacks as seven Kampfgruppen moved to Austria in preparation for the Balkans Campaign in Yugoslavia and Greece. The shortage of bombers caused OKL to improvise. Some 50 Junkers Ju 87 Stuka dive-bombers and Jabos (fighter-bombers) were used, officially classed as Leichte Kampfflugzeuge (“light bombers”) and sometimes called Leichte Kesselringe (“Light Kesselrings”). The defences failed to prevent widespread damage but on some occasions did prevent German bombers concentrating on their targets. On occasion, only one-third of German bombs hit their targets.
The diversion of heavier bombers to the Balkans meant that the crews and units left behind were asked to fly two or three sorties per night. Bombers were noisy, cold, and vibrated badly. Added to the tension of the mission which exhausted and drained crews, tiredness caught up with and killed many. In one incident on 28/29 April, Peter Stahl of KG 30 was flying on his 50th mission. He fell asleep at the controls of his Ju 88 and woke up to discover the entire crew asleep. He roused them, ensured they took oxygen and Dextro-Energen tablets, then completed the mission.
The Luftwaffe could still inflict much damage and after the German conquest of Western Europe, the air and submarine offensive against British sea communications became much more dangerous than the German offensive during the First World War. Liverpool and its port became an important destination for convoys heading through the Western Approaches from North America, bringing supplies and materials. The considerable rail network distributed to the rest of the country. Air attacks sank 39,126 long tons (39,754 t) of shipping, with another 111,601 long tons (113,392 t) damaged. Minister of Home Security Herbert Morrison was also worried morale was breaking, noting the defeatism expressed by civilians. Other sources point out that half of the 144 berths in the port were rendered unusable and cargo unloading capability was reduced by 75 percent. Roads and railways were blocked and ships could not leave harbour. On 8 May 1941, 57 ships were destroyed, sunk or damaged, amounting to 80,000 long tons (81,000 t). Around 66,000 houses were destroyed and 77,000 people made homeless (“bombed out”), with 1,900 people killed and 1,450 seriously hurt on one night.) Operations against London up until May 1941 could also have a severe impact on morale. The populace of the port of Hull became “trekkers”, people who made a mass exodus from cities before, during and after attacks. The Luftwaffe attacks failed to knock out railways or port facilities for long, even in the Port of London, a target of many attacks. The Port of London in particular was an important target, bringing in one-third of overseas trade.
Licerpool after amn air ra,d
On 13 March, the upper Clyde port of Clydebank near Glasgow was bombed Clydebank Blitz. All but seven of its 12,000 houses were damaged. Many more ports were attacked. Plymouth was attacked five times before the end of the month while Belfast, Hull, and Cardiff were hit. Cardiff was bombed on three nights, Portsmouth centre was devastated by five raids. The rate of civilian housing lost was averaging 40,000 people per week dehoused in September 1940. In March 1941, two raids on Plymouth and London dehoused 148,000 people. Still, while heavily damaged, British ports continued to support war industry and supplies from North America continued to pass through them while the Royal Navy continued to operate in Plymouth, Southampton, and Portsmouth. Plymouth in particular, because of its vulnerable position on the south coast and close proximity to German air bases, was subjected to the heaviest attacks. On 10/11 March, 240 bombers dropped 193 tons of high explosives and 46,000 incendiaries. Many houses and commercial centres were heavily damaged, the electrical supply was knocked out, and five oil tanks and two magazines exploded. Nine days later, two waves of 125 and 170 bombers dropped heavy bombs, including 160 tons of high explosive and 32,000 incendiaries. Much of the city centre was destroyed. Damage was inflicted on the port installations, but many bombs fell on the city itself. On 17 April 346 tons of explosives and 46,000 incendiaries were dropped from 250 bombers led by KG 26. The damage was considerable, and the Germans also used aerial mines. Over 2,000 AAA shells were fired, destroying two Ju 88s. By the end of the air campaign over Britain, only eight percent of the German effort against British ports was made using mines.
In the north, substantial efforts were made against Newcastle-upon-Tyne and Sunderland , which were large ports on the English east coast. On 9 April 1941 Luftflotte 2 dropped 150 tons of high explosives and 50,000 incendiaries from 120 bombers in a five-hour attack. Sewer, rail, docklands, and electric installations were damaged. In Sunderland on 25 April, Luftflotte 2 sent 60 bombers which dropped 80 tons of high explosive and 9,000 incendiaries. Much damage was done. A further attack on the Clyde, this time at Greenock, took place on 6 and 7 May. However, as with the attacks in the south, the Germans failed to prevent maritime movements or cripple industry in the regions.
The last major attack on London was on 10/11 May 1941, on which the Luftwaffe flew 571 sorties and dropped 800 tonnes of bombs. This caused more than 2,000 fires; 1,436 people were killed and 1,792 seriously injured, which affected morale badly. Another raid was carried out on 11/12 May 1941. Westminster Abbey and the Law Courts were damaged, while the Chamber of the House of Commons was destroyed. One-third of London’s streets were impassable. All but one railway station line was blocked for several weeks. This raid was significant, as 63 German fighters were sent with the bombers, indicating the growing effectiveness of RAF night fighter defences.
RAF night fighters
“British cities are not hapless targets anymore. They are dangerous places to fly over. My pilots are lucky to survive in each bombing mission” General Hugo Sperrle , commander of Luftflotte 3
German air supremacy at night was also now under threat. British night-fighter operations out over the Channel were proving successful. This was not immediately apparent. The Bristol Blenheim F.1 carried four .303 in (7.7 mm) machine guns which lacked the firepower to easily shoot down a Do 17, Ju 88 or Heinkel He 111. The Blenheim had only a small speed advantage to overhaul a German bomber in a stern-chase. Added to the fact an interception relied on visual sighting, a kill was most unlikely even in the conditions of a moonlit sky. The Boulton Paul Defiant , despite its poor performance during daylight engagements, was a much better night fighter. It was faster, able to catch the bombers and its configuration of four machine guns in a turret could (much like German night fighters in 1943–1945 with Schräge Musik ) engage the German bomber from beneath. Attacks from below offered a larger target, compared to attacking tail-on, as well as a better chance of not being seen by the crew (so less chance of evasion), as well as greater likelihood of detonating its bomb load. In subsequent months a steady number of German bombers would fall to night fighters.
Improved aircraft designs were in the offing with the Bristol Beaufighter, then under development. It would prove formidable but its development was slow. The Beaufighter had a maximum speed of 320 mph (510 km/h), an operational ceiling of 26,000 ft (7,900 m), a climb rate of 2,500 ft (760 m) per minute and its battery of four 20 mm (0.79 in) Hispano cannon and six .303 in Browning machine guns was much more lethal. On 19 November, John Cunningham of No. 604 Squadron RAF shot down a bomber flying an AI-equipped Bristol Beaufighter, the first air victory for the airborne radar. In November and December 1940, the Luftwaffe flew 9,000 sorties against British targets and RAF night fighters claimed only six shot down. In January 1941, Fighter Command flew 486 sorties against 1,965 made by the Germans. Just three and twelve were claimed by the RAF and AA defences respectively. In the bad weather of February 1941, Fighter Command flew 568 sorties to counter the Luftwaffe which flew 1,644 sorties. Night fighters could claim only four bombers for four losses.
By April and May 1941, the Luftwaffe was still getting through to their targets, taking no more than one- to two-percent losses per mission. On 19/20 April 1941, in honour of Hitler’s 52nd birthday, 712 bombers hit Plymouth with a record 1,000 tons of bombs. Losses were minimal. In that month, 23 German bombers were lost with 14 confirmed to have been shot down by night fighters. On 3/4 May, nine were shot down in one night. On 10/11 May, London suffered severe damage, but 14 German bombers were downed , seven of them claimed by RAF nightfighters. (One German pilot later remarked “We did not need to wear gloves over London anymore , their flak keeps us warm”) In a bizarre incident one more German Me-110 aircraft crashed down over Scotland same night , its pilot parachuted down and captured while insisting he came on his own will to make peace with Britain , he was no other than Rudolf Hess , Hitler’s secretary in Nazi Party.
In May 1941, RAF night fighters shot down 38 German bombers in total. 27 more bombers were shot down by British anti aircraft gunners same month. By the end of May, Kesselring’s Luftflotte 2 had been withdrawn, leaving Hugo Sperrle’s Luftflotte 3 as a token force to maintain the illusion of strategic bombing. Hitler now had his sights set on attacking the USSR with Operation Barbarossa, and the Blitz came to end.
Luftwaffe losses
Between 20 June 1940, when the first German air operations began over Britain, and 31 March 1941, OKL recorded the loss of 2,265 aircraft over the British Isles, a quarter of them fighters and one third bombers. At least 3,363 Luftwaffe aircrew were killed, 2,641 missing and 2,117 wounded. Total losses could have been as high as 600 bombers, just 1.5 per cent of the sorties flown. A significant number of the aircraft not shot down after the resort to night bombing were wrecked during landings or crashed in bad weather.
The military effectiveness of bombing varied. The Luftwaffe dropped around 45,000 short tons (41,000 t) of bombs during the Blitz, which disrupted production and transport, reduced food supplies, and shook British morale. The bombing also helped to support the U-boat blockade by sinking some 58,000 long tons (59,000 t) of shipping and damaging 450,000 long tons (460,000 t) more. Despite the bombing, British production rose steadily throughout this period, although there were significant falls during April 1941, probably influenced by the departure of workers for Easter Holidays, according to the British official history. The official history volume British War Production (Postan, 1952) noted that the greatest effect on output of warlike stores was on the supply of components and dispersal of production rather than complete equipments.
In aircraft production, the British were denied the opportunity to reach the planned target of 2,500 aircraft in a month, arguably the greatest achievement of the bombing, as it forced the dispersal of the industry, at first because of damage to aircraft factories and then by a policy of precautionary dispersal. In April 1941, when the targets were British ports, rifle production fell by 25 per cent, filled-shell production by 4.6 per cent and in small-arms production 4.5 per cent. The strategic impact on industrial cities was varied; most took from 10–15 days to recover from heavy raids, although Belfast and Liverpool took longer. The attacks against Birmingham took war industries some three months to recover fully. The exhausted population took three weeks to overcome the effects of an attack.
The air offensive against the RAF and British industry failed to have the desired effect. More might have been achieved had OKL exploited the vulnerability of British sea communications. The Allies did so later when Bomber Command attacked rail communications and the United States Army Air Forces targeted oil, but that would have required an economic-industrial analysis of which the Luftwaffe was incapable. OKL instead sought clusters of targets that suited the latest policy (which changed frequently), and disputes within the leadership were about tactics rather than strategy. Though militarily ineffective, the Blitz cost around 19,000 civilian lives, may have injured another 139,000 people, and did enormous damage to British infrastructure and housing stock