Battle of Britain
2008/9 Schools Wikipedia Selection. Related subjects: British History Post 1900; World War II
"Battle for Britain" redirects here. There is also a David Bowie song of that title. For the Private Eye comic strip, see Battle for Britain (Private Eye).
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Battle of Britain is the name given to the strategic effort by the Luftwaffe during the Second World War to gain air superiority over Fighter Command. The name derives from an 18 June 1940 speech in the House of Commons by Prime Minister Winston Churchill, "The Battle of France is over. I expect the Battle of Britain is about to begin..."
Had it been successful, the planned amphibious and airborne landings in Britain of Operation Sealion would have followed. The Battle of Britain was the first major campaign to be fought entirely by air forces. It was the largest and most sustained bombing campaign attempted up until that date. The failure of Nazi Germany to destroy Britain's air defence or to break British morale is considered their first major defeat.
Neither Hitler nor the Oberkommando der Wehrmacht (OKW) believed it possible to carry out a successful amphibious assault on the British Isles until the RAF had been neutralized. Secondary objectives were to destroy aircraft production and ground infrastructure, to attack areas of political significance, and to terrorize the British people into seeking an armistice or surrender. Some historians have argued no invasion could have succeeded, asserting the massive superiority of the Royal Navy over the Kriegsmarine would have made Sealion a disaster. They argue the Luftwaffe would have been unable to prevent decisive intervention by British cruisers and destroyers, even with air superiority.
British historians date the battle from 10 July to 31 October 1940, which represented the most intense period of daylight bombing. German historians usually place the beginning of the battle in mid-August 1940 and end it in May 1941, on the withdrawal of the bomber units in preparation for the attack on the USSR.
Background
Luftwaffe attacks on Britain began with raids on naval targets, with bombers being shot down over the Firth of Forth on 16 October 1939 and over Scapa Flow on the following day, but there were no major attacks during the Phoney War period, a lull in fighting that Hitler ended on 10 May 1940 with his invasion of the Low Countries.
Following the evacuation of the British from Dunkirk (Operation DYNAMO), and the French surrender on 22 June 1940, Hitler believed the war was practically over and the British, defeated on the continent and without European allies, would quickly come to terms with Germany. Although there was an element of British public and political sentiment favouring negotiated peace with a clearly ascendant Germany, among them the Foreign Secretary, Lord Halifax, the recently-installed Churchill nonetheless refused to consider an armistice with Hitler's Germany. Churchill's skillful use of rhetoric hardened public opinion against a peaceful resolution and prepared the British for a long war.
On 16 July, in an effort to finish the war in the west, Hitler ordered the rapid preparation of a plan to invade Britain. Hitler hoped to frighten Britain into peace and saw the preparations as a means to apply pressure. The plan was prepared by OKW. The operation, code-named Seelöwe ("Sealion"), was scheduled for mid-September 1940 and called for landings on the south coast of Great Britain, backed by an airborne assault. All preparations were to be made by mid-August.
The Kriegsmarine was reluctant to launch an invasion, and on 11 July, Admiral Raeder told Hitler invasion could only be contemplated as a last resort, and only then with full air superiority. The Kriegsmarine had a limited number of ships, while the Royal Navy had over 50 destroyers and dozens of cruisers and battleships in home waters. In the event of a seaborne invasion, the British Home Fleet would sortie from their nearby bases and attack the invasion force, something the Kriegsmarine could do little to counter. The only way Germany would be able to prevent Royal Navy interference would be with the Luftwaffe, primarily using dive bombers, which would require complete air superiority, because the bombers were so vulnerable to attack. Nevertheless, Hitler was determined the invasion go ahead and ordered all services to make preparations for an amphibious assault once air superiority had been achieved.
Opposing forces
The Luftwaffe was facing a more capable opponent than it had met before: a sizable, highly-coordinated, well-supplied air force, fielding aircraft able to match the German Messerschmitt Bf 109E and Bf 110C. The majority of the RAF's fighting would rest upon the workhorse Hurricane Mk I. More shocking to the German pilots was the newer Spitfire Mk I, which was quickly recognised as a world-class fighter. Most of the fighters they had encountered thus far in the war had not, despite mainly strong showings by opposing pilots, reached this standard.
Aircraft
The Bf 109E was marginally superior to the Hurricane. The Bf 109E and the Spitfire, in certain key areas, had the advantage over each other. The 109 could outclimb both. The Spitfire was slightly faster at medium heights, was more manoeuvrable, and possessed a stronger airframe as well as heavier armour than the Bf 109E-1. However, because of their carburetted engines, neither it nor the Hurricane could simply dive away from an opponent, as the 109 could. The Spitfire, initially, had a better protected cockpit with bulletproof windscreen and an armoured plate behind the pilot's seat. The Messerschmitt Bf 109 E-3 received extra armour behind the pilots head, and seat armour. The canopy was also modified for better visibility. The Bf 109 was also equipped with Self-sealing fuel tanks, although this could not prevent destruction from tracer rounds.
The Bf 109 had a slightly higher speed at high altitude, better dive speed, and a fuel injected engine (the Daimler-Benz DB 601), giving Germans the ability to perform negative-gee manoeuvres without the engine cutting out, and thus the option to disengage at will. This advantage could prove moot when pursuing a Spitfire. The superioriy of the Spitfires rate of roll would ensure the Messerschmitt overshot, should the Spitfire pilot perform a half-roll, then dive. The German fighter would gain too much speed, lessening the response of its control surfaces due to the pressure, and then would be unable to correct and counter the Spitfires defensive manoeuvre. The German fighter had a heavier armament, with its two 20 mm MG FF cannon. This gave it a greater punch than the eight .303 (7.7 mm) machineguns of the British fighters, but the low muzzle velocity of the cannon, where the shells dropped quite quickly after firing, meant the Messerschmitt pilots had to open fire from close range.
On 22 November 1939 a Bf 109E-3 (Wk-Nr 1304 of JG 76) landed intact in France. Evaluated at RAF Farnborough, the Bf 109 was used in mock combats with Spitfire Mk Is. The RAF test pilots found the Bf 109 "superior in all aspects bar monoeuvrability and turning circle". Level speed was reported to be even, however when the Bf 109 pulled out of a dive at speed and then proceeded to climb steeply at slow speed, the Spitfire had difficult in keeping up. The margins were apparently reduced when the Spitfire was fitted with a constant speed airscrew.
Werner Mölders flew a captured Spitfire Mk I in June 1940 (one of three examples obtained in flyable condition by the Luftwaffe). Mölders reported that the Spitfire was "excellent in the turn" but a "rotten dogfighter", due to the Spitfires " Carburettor engine". Mölders also noted, "in any vertical dogfight at constantly changing altitude it's either continually over-revving or never develops full power at all." In addition there were other smaller details in which they differed.
The Junkers Ju 87 Stuka was slow and possessed inadequate defences. Furthermore, it could not be effectively protected by fighters, because of its low speed and the very low altitudes at which it ended its dive bomb attacks. The Stuka depended on air superiority, the very thing being contested over Britain. It was therefore withdrawn from attacks on Britain early in the campaign, after prohibitive losses, leaving the Luftwaffe short of precision ground attack aircraft..
The Me 110 underperformed because it was deployed in a role for which it was never intended. It was an excellent fighter-bomber and interceptor, having (at least at altitudes greater than 15,000 ft (4,600 m)) a maximum speed better than the Hurricane and not much inferior to the Spitfire, and a heavy armament capable of dealing with any enemy bomber. When used as a light bomber it proved very effective. It was still formidable as a high escort for bombers, when it could dive down upon the enemy, fire and then break contact. As a fighter, overall, its lack of manoeuvrability made it an easy target for British fighters. It was pressed into this role because the Bf 109 lacked the range necessary to escort bombers to targets beyond the south-east corner of England. To correct this the Oberkommando der Luftwaffe had ensured the introduction of the Bf 109 E-7 in August 1940, equipped with a 300 litre external fuel tank to complement its 400 litre internal tank. Earlier use of external tanks had been halted due to leakages in the plywood moulds, which eroded when exposed to the elements.
The Bf 109 was also used as a fighter-bomber. Bf 109 E-7s had the ability to carry a 250kg bomb underneath the fuselage. The E-7/U2 model had extra armour installed to protect the Jabos. The Bf 109, unlike the Stuka could then, after releasing its ordnance, fight on equal terms with RAF fighters.
For the British, the main disappointment was the performance of the Boulton-Paul Defiant two-seat turret fighters and Fairey Battle bombers. These aircraft, which before the war were expected to fill the bomber-killer and precision strike roles respectively, were found to be too vulnerable. The Battles suffered horrendous losses in France and were eventually put into reserve to take on the invasion fleet if it were ever launched. The Defiants were too cumbersome to tangle with the Bf 109s, and after suffering heavy losses in the early part of the battle they were reassigned as "cat's eye" night-fighters, where they had little more success. There has been some criticism of the decision to keep these aircraft operational instead of retiring and scrapping them, allowing their Merlin engines to be turned over to fighters and their pilots (about three thousand in all) to be retrained on Hurricanes, thereby freeing large numbers of high-time, combat-experienced Hurricane pilots for Spitfires.
Pilots
The British had fewer experienced pilots at the start of the battle, and it was the lack of trained pilots, rather than the lack of machines, that became the greatest concern for Dowding. Drawing from regular RAF forces as well as the Auxiliary Air Force and the Volunteer Reserve, the British could muster some 1,103 fighter pilots on 1 July. The selection processes of potential RAF candidates were more concerned with social standing than actual aptitude leading up to the war. Replacement pilots, with little actual flight training and no gunnery training whatsoever, suffered high casualty rates. RAF forces were bolstered by personnel from other countries and/or air forces) including:
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The Luftwaffe could muster more fighter pilots, 1,450, who were more experienced overall. Drawing from a cadre of Spanish Civil War veterans, they had comprehensive courses in aerial gunnery, as well as instructions in tactics that were suited for fighter versus fighter combat. Luftwaffe training manuals also discouraged heroism, stressing the utmost importance of attacking only when the odds were in the pilot's favour. This rule could not be followed in close bomber escort duties though, since the fighter gave up tactical flexibility and the advantage of height.
Air combat tactics
In the early phases of the battle, the RAF was hindered by its reliance on obsolete formations. These restricted squadrons to tight 12 aircraft formations composed of three-aircraft "sections" in tight "Vs" ("vics"). With four sections flying together in tight formation, only the squadron leader at the front was free to actually watch for the enemy; the other pilots had to concentrate on keeping station. RAF fighter training also emphasized by-the-book attacks by sections breaking away in sequence. Fighter Command recognised the weaknesses of this rigid structure early in the battle, but it was felt too risky to change tactics in the midst of the battle, because replacement pilots, often with only minimal actual flying time, could not be readily retrained, and inexperienced RAF pilots needed firm leadership in the air only rigid formations could provide. German pilots dubbed the RAF formations Idiotenreihen ("rows of idiots") because they left squadrons vulnerable to attack. Front line RAF pilots were acutely aware of the inherent deficiencies of their own tactics. A compromise was adopted whereby squadron formations used much looser formations with one or two aircraft flying independently above and behind (dubbed "weavers") to provide increased observation and rear protection; these, often the least experienced men, were also often the first to die. After the battle, RAF pilots adopted a variant on the German formations with some success.
The Luftwaffe employed the looser and flexible four-ship Schwarm (two pairs, or Rotte, each consisting of a leader and a wingman) in an open formation. Each Schwarm in a Staffel flew staggered and with plenty of room in between them, making the formation difficult to spot at longer ranges and allowing for a great deal of flexibility. This formation was developed during the Spanish Civil War by Günther Lützow and Werner Mölders and other Luftwaffe pilots, based on principles dating to Oswald Boelcke in 1916. In the Luftwaffe formations, the pair allowed the Rottenführer to concentrate on getting kills, while his wingman protected him and scanned for threats.
Luftwaffe strategy
The Luftwaffe was designed as a tactical weapon to support the Army on the battlefield. In Poland and France, the Luftwaffe had operated jointly with the Wehrmacht in its blitzkrieg. In the Battle of Britain, however, the Luftwaffe had to be decisive in its own right. This new role was something it was unsuited for. Its main task was to ensure air supremacy over southeast England, to pave the way for an invasion fleet.
The Luftwaffe regrouped after the Battle of France into three Luftflotten (Air Fleets) on the Britain's southern and northern flanks. Luftflotte 2, commanded by Generalfeldmarschall Albrecht Kesselring, was responsible for the bombing of southeast England and the London area. Luftflotte 3, under Generalfeldmarschall Hugo Sperrle, targeted the West Country, Midlands, and northwest England. Luftflotte 5, led by Generaloberst Hans-Jürgen Stumpff from his headquarters in Norway, targeted the north of England and Scotland. As the battle progressed, command responsibility shifted, with Luftflotte 3 taking more responsibility for the night-time Blitz attacks while the main daylight operations fell upon Luftflotte 2's shoulders.
Initial Luftwaffe estimates allotted four days to defeat Fighter Command in southern England, followed by four weeks for the bombers and long-range fighters to mop up the rest of the country and destroy the British aircraft industry. The plan was to begin with attacks on airfields near the coast, gradually moving inland toward London and the ring of sector airfields defending it. Later reassessments gave the Luftwaffe five weeks to establish temporary air superiority over England within the period from 8 August to 15 September. To achieve this goal, Fighter Command had to be destroyed on the ground or in the air with the Luftwaffe maintaining a high enough kill ratio to avoid depleting its own forces to such a level that it could not support an invasion. The only alternative to the goal of air superiority was a terror bombing campaign aimed at the civilian population, but this alternative was considered unfeasible and was expressly forbidden by Hitler.
The Luftwaffe kept broadly to this scheme, but its commanders had differences of opinion on strategy. Sperrle wanted to eradicate the air defence infrastructure by bombing it. His counterpart, Kesselring, championed attacking London directly—either to bombard the British government into submission or to draw RAF fighters into a decisive battle. Göring did nothing to resolve this disagreement between his commanders, and only vague directives were set down during the initial stages of the battle, with Göring seemingly unable to decide upon which strategy to pursue. He seemed at times obsessed with maintaining his own power base in the Luftwaffe and indulging his outdated beliefs on air fighting, which were later to lead to tactical and strategic errors.
Tactics
The Luftwaffe varied its tactics considerably to try to find a way through the RAF defences. It launched many free-roving fighter sweeps, known as Freie Jagd ("Free Hunts"), to draw up RAF fighters. RAF fighter controllers, however, were often able to detect these and position squadrons to avoid them, keeping to Dowding's plan to preserve fighter strength for the bomber formations. The Luftwaffe also tried using small formations of bombers as bait, covering them with large numbers of escorts. This was more successful, but escort duty tied the fighters to the bombers' slow speed and made them more vulnerable. Casualties were greatest among the escort units.
Standard tactics for raids soon became an amalgam of techniques. A free hunt would precede a raid to try to sweep any defenders out of the raid's path. The bombers would then fly in at altitudes between 10,000 and 16,000 feet (4,900 m), sometimes closely escorted by fighters. A "detached" escort or "top cover" would fly above the bombers and maintain a distant watch.
Luftwaffe tactics were influenced by their fighters, which were divided into single-engined Bf 109s and twin-engine Bf 110s. The Bf 110 Zerstörer ("destroyer") proved too vulnerable to the nimble single-engined RAF fighters. Soon, they had to be given escorts of their own and were eventually restricted in their employment. This meant the bulk of fighter duties fell on the Bf 109. Fighter tactics were then complicated by bomber crews who demanded closer protection. Due to a similar concerns over losses in the hard-fought battles of 15 August and 18 August, Göring ordered an increase in close escort duties. This decision shackled many of the Bf 109s to the bombers and, although they were more successful at protecting the bomber forces, casualties amongst the fighters mounted primarily because they were forced to fly and maneouvre at reduced speeds.
Adolf Galland noted:
We had the impression that, whatever we did, we were bound to be wrong. Fighter protection for bombers created many problems which had to be solved in action. Bomber pilots preferred close screening in which their formation was surrounded by pairs of fighters pursuing a zigzag course. Obviously, the visible presence of the protective fighters gave the bomber pilots a greater sense of security. However, this was a faulty conclusion, because a fighter can only carry out this purely defensive task by taking the initiative in the offensive. He must never wait until attacked because he then losses the chance of acting. We fighter pilots certainly preferred the free chase during the approach and over the target area. This, in fact, gives the greatest relief and the best protection for the bomber force.
The limited, 600 km (360 mi) total range of the Bf 109E single engined fighters was also a serious limitation on the Luftwaffe's tactics in the battle-the longer (at 800 km/500 mi) range Focke-Wulf Fw 190, then still only existent in prototype form, would have posed a much more serious threat to the Royal Air Force had it been available.
Intelligence
The Luftwaffe was ill-served by its lack of intelligence about the British defences. The German intelligence services were fractured and plagued by rivalries; their overall performance was amateurish. By 1940, there were few if any German agents operating in the UK and a handful of bungled attempts to insert spies into the country were foiled. This meant the Luftwaffe had almost no recent knowledge of the workings of the RAF's air defences, in particular of the crucial command and control system built before the war. Even when good information existed, such as a November 1939 Abwehr assessment of Fighter Command strengths and capabilities by Abteilung V, it was ignored if it did not match conventional preconceptions.
Throughout the battle, the Luftwaffe had to launch numerous reconnaissance sorties to make up for the poor intelligence. Reconnaissance aircraft (at first mostly Dornier Do 17s, but increasingly Bf 110s) proved easy prey for British fighters, as it was seldom possible for them to be escorted by Bf 109s. Thus, the Luftwaffe operated "blind" for much of the battle, unsure of its enemy's true strengths, capabilities, and deployments. Many times the leadership believed Fighter Command's strength had collapsed, while raids against supposed fighter airfields fell instead on bomber or coastal defence stations. The results of bombing and air fighting were consistently exaggerated, due to over-enthusiastic claims and the difficulty of effective confirmation over enemy territory. In the euphoric atmosphere of perceived victory, Luftwaffe leadership became increasingly disconnected from reality. This lack of leadership and solid intelligence meant the Germans did not adopt any consistent strategy, even when the RAF had its back to the wall. Moreover, there was never a systematic focus on any one type of target (such as airbases, radar stations, or aircraft factories), so the already haphazard effort was further diluted.
Navigational aids
While the British were using radar for air defence more effectively than the Germans realised, the Luftwaffe attempted to press its own offensive advantage with advanced radio navigation systems the British were initially not aware of. One of these was Knickebein ("crooked leg"), a system where carefully positioned radio transmitters in friendly territory broadcast specially targeted navigational beams which intersected over specific bombing targets in enemy territory. Bombers equipped to detect these beams could be guided towards a target and receive a signal to drop their bombs when they were (roughly) overhead. This allowed for somewhat more accurate bombing at night, when British air defence was at its weakest.
Although British intelligence had heard of proposals for this system, they were not taken seriously until a British science advisor to MI6, Dr. Reginald Jones, gathered evidence of its existence and the threat it posed. He then convinced the high command of the menace and confirmed it with special reconnaissance flights. Jones was put in charge of developing countermeasures, which often involved interfering with the beams to make attacking aircraft go widely off course. Although the Germans resorted to other navigational systems, Jones and the Telecommunications Research Establishment (TRE) were able to neutralise each in turn. This so-called Battle of the Beams resulted in a markedly reduced German bombing accuracy. With the beams no longer accurate, however, many civilian areas that would not normally have been targeted were bombed.
RAF strategy
The Dowding system
The keystone of the British defence was the complex infrastructure of detection, command, and control that ran the battle. This was the "Dowding System," after its chief architect, Air Chief Marshal Sir H.C.T. "Stuffy" Dowding, the leader of RAF Fighter Command.
Groups
The UK's airspace was divided up into four Groups.
- 10 Group defended Wales and the West Country and was commanded by Air Vice-Marshal Sir Quintin Brand.
- 11 Group covered the southeast of England and the critical approaches to London and was commanded by Air Vice-Marshal Keith Park.
- 12 Group defended the Midlands and East Anglia and was led by Air Vice-Marshal Trafford Leigh-Mallory.
- 13 Group covered the north of England, Scotland and Northern Ireland and was commanded by Air Vice-Marshal Richard Saul.
At the HQ of each Group (e.g. RAF Uxbridge, for 11 Group), information from Fighter Command headquarters would be noted on plotting tables, large maps on which counters marking the incoming raids would be moved, and RAF officers known as Fighter Controllers could then order a response.
Despite appearances, the Groups were not mutually supporting; Park, for instance, could only request, not demand, assistance from Brand (from whom he often got it), nor from Leigh-Mallory (from whom he more often did not). This was because Dowding had never issued standing orders to assist, nor created a method to co-ordinate it.
Sectors
The Group areas were subdivided into Sectors; each commanding officer was assigned between two and four squadrons. Sector stations, comprising an aerodrome with a command post, were the heart of this organisation, though they also had satellite airfields to disperse squadrons to. When ordered by their Group HQ, the sector stations would "scramble" their squadrons into the air. Once airborne, the squadrons would be directed by radio-telephone (R/T) from their sector station. Squadrons could be ordered to patrol airfields or vital targets or be "vectored" to intercept incoming raids.
Limitations
Though it was the most sophisticated air defence system in the world at that time, the Dowding System had many limitations, including, but not often stressed, its emphatic need for qualified ground maintenance personnel, many of whom had received their training under the Aircraft Apprentice scheme instituted by Hugh Trenchard. RDF (radar) was subject to significant errors and the Observer Corps had difficulties tracking raids at night and in bad weather. R/T communications with airborne fighters were restricted because of the RAF's use of High-Frequency (HF) radio sets. HF radio was limited in range and even with a network of relay stations, the squadrons could not roam more than one or two sectors from their airfields. It was also restricted to a single frequency per squadron, making inter-squadron communication impossible. Finally, the system for tracking RAF fighters, known as HF/DF or " Huff-Duff", restricted sectors to a maximum of four squadrons in the air.
This is, in part, a reflection of the novelty of the type of combat, as well as the control system. It was perfectly possible for Sector Control to have been assigned one frequency for all fighters to "listen out" on (or "guard", in modern parlance), with "roving" intercept guidance, rather than the close positive control used in the event, which limited controllers' ability to handle large numbers of interceptors.
Efficiency
In spite of this, Fighter Command at times achieved interception rates greater than 80%. The R/T problems were solved late in the battle with the adoption of Very High-Frequency (VHF) radio sets, which gave clearer voice communications, had longer range, and provided multiple channels. For all of its faults, RAF's system of ground control directed its fighters to be where they were needed. The Luftwaffe, with no such system, was always at a disadvantage.
Effect of signals intelligence
It is unclear how much the British intercepts of the Enigma cipher, used for high-security German radio communications, affected the battle. Ultra, the information obtained from Enigma intercepts, gave the highest echelons of the UK's command a view of German intentions but it seems little of this material filtered down to Hugh Dowding's desk. (It would have had little tactical value in any case.) However, the radio listening service (known as Y Service), monitoring the patterns of Luftwaffe radio traffic, contributed considerably to the early warning of raids.
Tactics
The weight of the battle fell upon 11 Group. Keith Park's tactics were to dispatch individual squadrons to intercept raids. The intention was to subject attackers to continual attacks by relatively small numbers of aircraft and try to break up the tight formations of bombers. Once formations had fallen apart, stragglers could be picked off one by one. Where multiple squadrons reached a raid the procedure was for the slower Hurricanes to tackle the bombers while the more agile Spitfires held up the fighter escort. This ideal was not always achieved, however, and sometimes the Spitfires and Hurricanes reversed roles.
During the battle, some commanders, notably Leigh-Mallory, proposed squadrons be formed into " Big Wings," consisting of at least three squadrons, to attack the enemy en masse, a method pioneered by Douglas Bader. Proponents of this tactic claimed interceptions in large numbers caused greater enemy losses while reducing their own casualties. Opponents pointed out the big wings would take too long to form up, and the strategy ran a greater risk of fighters being caught on the ground refuelling. The big wing idea also caused pilots to over-claim their kills, due to the confusion of a more intense battle zone. This led to the belief big wings were far more effective than they actually were.
The issue caused intense friction between Park and Leigh-Mallory, as 12 Group were tasked with protecting 11 Group's airfields whilst Park's squadrons intercepted incoming raids. However, the delay in forming up Big Wings meant this often did not arrive until after German bombers had hit 11 Group's airfields. Dowding, in an effort to highlight the problem of the Big Wing's performance, submitted a report compiled by Park to the Air Ministry on 15 November. In the report he highlighted the fact that during the period of 11 September – 31 October the extensive use of the Big Wing had resulted in just 10 interceptions and one German aircraft destroyed, but his report was ignored.. Postwar analysis agrees Dowding's and Park's approach was best for 11 Group. Dowding's removal form his post in November 1940 has been blamed on this struggle between Park and Leigh-Mallory's daylight strategy. However the intensive raids and destruction wrought during the Blitz also damaged Dowding and Park in particular, for the failure to produce an effective night-fighter defence system, something for which the influential Leigh-Mallory had long criticised them.
Bomber and Coastal Command contributions
Bomber Command and Coastal Command aircraft flew offensive sorties against targets in Germany and France during the battle. After the initial disasters of the war, with Vickers Wellington bombers shot down in large numbers attacking Wilhelmshafen and the slaughter of the Fairey Battle squadrons sent to France, it became clear Bomber Command would have to operate mainly at night to achieve any results without very high losses. From 15 May 1940 a night-time bomber campaign was launched against German oil industry, communication and forests/crops, mainly in the Ruhr area.
As the threat mounted, Bomber Command changed targeting priority on 3 June 1940 to attack the German aircraft industry and to attack harbours and shipping able to support an invasion of Great Britain. From early August the assembling invasion fleet in French ports got a high priority target as well. The large barges intended by the Germans to transport troops across the Channel were targeted by bombers. In addition the Germans had few Freya radar stations set up in France, meaning air defence of the French harbours were not nearly as good as the air defences over Germany. In September 1940, Bomber Command was directing some 60% of its strength against the Channel ports. Unexplained is why German fighter and bomber bases in France, which were jammed with aircraft and well-known to RAF intelligence, were never attacked. Even a handful of Blenheims attacking a few times in July could have inflicted more damage than all of Fighter Command for the duration of the battle.
Coastal Command directed its attention towards the protection of British shipping, and the destruction of enemy shipping. As invasion became more likely, it participated in the strikes on French harbours and airfields, laying mines, and mounting numerous reconnaissance missions over the enemy held coastline. In all, some 9,180 sorties were flown by bombers from July to October 1940. Compared to the 80,000 sorties flown by fighters it is relatively little, but bombers suffered about 50% the number of casualties as their fighter colleagues. The bomber contribution was therefore much more dangerous on a loss-per-sortie comparison.
Phases of the Battle
The Battle can be roughly divided into four phases:
- 10 July– 11 August: Kanalkampf, ("the Channel battles").
- 12 August– 23 August: Adlerangriff ("Eagle Attack"), the early assault against the coastal airfields.
- 24 August– 6 September: the Luftwaffe targets the airfields. The critical phase of the battle.
- 7 September onwards: the day attacks switch to British towns and cities.
Channel battles
The Kanalkampf comprised a series of running fights over convoys in the English Channel and occasional attacks on the convoys by Stuka dive-bombers. It was launched partly because Kesselring and Sperrle were not sure about what else to do, and partly because it gave German aircrews some training and a chance to probe the British defenders. In general, these battles off the coast tended to favour the Germans, whose bomber escorts massively outnumbered the convoy patrols. The need for constant patrols over the convoys put a severe strain on RAF pilots and machines, wasting fuel, engine hours and exhausting the pilots, but eventually the number of ship sinkings became so great the British Admiralty cancelled all further convoys through the Channel. However, these early combat encounters provided both sides with experience. They also gave the first indications some of the aircraft, such as the Defiant and Bf 110, were not up to the intense dog-fighting that would characterise the battle.
Main assault
The main attack upon the RAF's defences was code-named Adlerangriff ("Eagle Attack").
Weather, which proved an important feature of the campaign, delayed Adlertag, ("Eagle Day") until 13 August 1940. On 12 August, the first attempt was made to blind the Dowding system when aircraft from the specialist fighter-bomber unit, Erprobungsgruppe 210 attacked four radar stations. Three were briefly taken off the air but were back working within six hours. The raids appeared to show British radars were difficult to knock out for any length of time. The failure to mount follow-up attacks allowed the RAF to get the stations back on the air, and Luftwaffe neglected strikes on the supporting infrastructure, such as phone lines or power stations, which could have rendered the radars useless, even if the towers themselves (which were very difficult to destroy) remained intact.
Adlertag opened with a series of attacks on coastal airfields, used as forward landing grounds for the RAF fighters. As the week drew on, the airfield attacks moved further inland, and repeated raids were made on the radar chain. 15 August was "The Greatest Day" when the Luftwaffe mounted the largest number of sorties of the campaign. Luftflotte 5 attacked the north of England. Believing Fighter Command strength to be concentrated in the south, raiding forces from Denmark and Norway ran into unexpectedly strong resistance. Inadequately escorted by Bf 110s, bombers were shot down in large numbers. As a result of the casualties, Luftflotte 5 did not appear in strength again in the campaign.
18 August, which had the greatest number of casualties to both sides, has been dubbed "The Hardest Day". Following the grinding battles of 18 August, exhaustion and the weather reduced operations for most of a week, allowing the Luftwaffe to review their performance. "The Hardest Day" had sounded the end for the Ju 87 in the campaign. This veteran of blitzkrieg was too vulnerable to fighters to operate over Britain, and to preserve the Stuka force, Göring withdrew them from the fighting. This removed the main Luftwaffe precision-bombing weapon and shifted the burden of pinpoint attacks on the already-stretched Erpro 210. Also, the Bf 110 had proven too clumsy for dog-fighting with single-engined fighters, and its participation was scaled back. It would only be used when range required it or when sufficient single-engined escort could not be provided for the bombers.
Göring made yet another fateful decision: to order more bomber escorts at the expense of free-hunting sweeps. To achieve this, the weight of the attack now fell on Luftflotte 2, and the bulk of the Bf 109s in Luftflotte 3 were transferred to Kesselring's command, reinforcing the fighter bases in the Pas de Calais. Stripped of its fighters, Luftflotte 3 would concentrate on the night bombing campaign. Göring, expressing disappointment with the fighter performance thus far in the campaign, also made a large change in the command structure of the fighter units, replacing many Geschwaderkommodoren with younger, more aggressive pilots like Adolf Galland and Werner Mölders.
Finally, Göring stopped the attacks on the radar chain. These were seen as unsuccessful, and neither the Reichsmarschall nor his subordinates realised how vital the Chain Home stations were to the defence. It was known radar provided some early warning of raids, but the belief among German fighter pilots was anything bringing up the " Tommies" to fight was to be encouraged.
Luftwaffe targets RAF airfields
On 19 August 1940, G&