Adlertag

("Eagle Day") was the first day of ("Operation Eagle Attack"), an operation by Nazi Germany's Luftwaffe (air force) intended to destroy the British Royal Air Force (RAF). The operation came during the Battle of Britain after Britain rejected all overtures for a negotiated peace with Germany. However, and subsequent operations failed to destroy the RAF or gain local air superiority.

On 16 July 1940 Hitler gave the German armed forces (Wehrmacht) Directive No. 16 ordering provisional preparations for the invasion of Britain.Trevor-Roper 2004, pp. 74–79. This operation was codenamed Operation Sea Lion (Unternehmen Seelöwe). Before this could be carried out, air superiority or supremacy was required. The Luftwaffe was to destroy the RAF in order to prevent it from attacking the invasion fleet or providing protection for the Royal Navy's Home Fleet, which might attempt to prevent a landing by sea. On 1 August Hitler gave the Luftwaffes commander-in-chief, Reichsmarschall Hermann Göring and the Oberkommando der Luftwaffe Directive No. 17 to launch the air assault.

The essential target was RAF Fighter Command. The service's destruction would deny the British their air superiority asset and feeling vulnerable to air attack might negotiate for peace. Throughout July and early August, the Germans made preparations for Adlertag. The date of the assault was postponed several times because of bad weather. Eventually it was carried out on 13 August 1940, inflicting significant damage and casualties on the ground, but, marred by poor intelligence and communication, they did not significantly impair Fighter Command's ability to defend British air space.Bungay 2000, p. 210.

Göring had promised Hitler that Adlertag and Adlerangriff would achieve the results required within days, or at worst weeks. It was meant to be the beginning of the end of RAF Fighter Command, but Adlertag and the following operations failed to destroy the RAF, or gain the necessary local air superiority.Bungay 2000, p. 210. As a result, Operation Sea Lion was postponed indefinitely.

Background

Strategic overview

After the declaration of war on Nazi Germany by Britain and France in the aftermath of the German invasion of Poland, nine months of stalemate took place along the Western Front. After the Polish Campaign, in October 1939, the planners of the Oberkommando der Luftwaffe (OKL – Luftwaffe (Air Force) High Command) and the Oberkommando der Wehrmacht (OKW – Supreme Command of the Armed Forces) turned their attentions to Western Europe.Healy 2007, pp. 3–5.

The German offensive—named Unternehmen Gelb (Operation Yellow), also known as the Manstein Plan—began in the west on 10 May 1940. The central campaign—the Battle of France—ended in Allied defeat and the destruction of the main French Army forces. The British Expeditionary Force escaped encirclement during the Battle of Dunkirk, but the Wehrmacht captured Paris on 14 June and overran half of France. The French surrendered on 25 June 1940.Hooton 2007, pp. 47–48, p. 77, p. 86.

With Western Europe neutralised, the OKL and OKW turned their attention to Britain, which was now home to the Allied base of operations in Europe. Hitler hoped Britain would negotiate for an armistice, for which he was prepared to offer generous terms. The tentative offers made by Hitler were rejected by the Churchill coalition government.Parker 2000, pp. 98–99. Hitler now ordered the Luftwaffe and Kriegsmarine to prepare for an amphibious assault of Britain, codenamed Operation Sealion. The Luftwaffe was to eliminate enemy air power and the Kriegsmarine was ordered to make all the necessary preparations for transporting the German army (Heer) across the English Channel. The Luftwaffe's task came first. Once the RAF had been rendered impotent, Göring and Hitler hoped that an invasion would be unnecessary.Murray 1983, p. 45. If this proved not to be the case, the Luftwaffe would then support the army and prevent the Royal Navy interdicting German sea traffic.Hooton 1997, p. 17–18.Parker 2000, p. 93. Göring named the offensive against the RAF as Operation Eagle Attack (Adlerangriff).Hooton 2010, p. 75.

Background: early battles The losses of the spring campaign had weakened the Luftwaffe before the Battle of Britain. Over 1,400 aircraft had been lost in the Battle of France on top of about 500 lost in conquering Poland in 1939 and Norway in 1940.Bungay 2000 p124 The service was forced to wait until it had reached acceptable levels before a main assault against the RAF could be made.Murray 1983, p. 44. Therefore, the first phase of the German air offensive took place over the English Channel. The Kanalkampf ("Channel battle") rarely involved attacks against RAF airfields inland, but encouraged RAF units to engage in battle by attacking British Channel convoys. These operations would last from 10 July to 8 August 1940.James 2000, p. 17. The attacks against shipping were not successful; only 24,000 tons (gross register) was sunk. Minelaying from aircraft proved more profitable, sinking 38,000 tons.James 2000, p. 43. The impact on Fighter Command was minimal. It had lost 74 fighter pilots killed or missing and 48 wounded in July, and its strength rose to 1,429 by 3 August. By that date, it was short only 124 pilots.James 2000, p. 45.

In the second phase of attacks, shipping, coastal airfields, radar and stations south of London were attacked during 8–18 August. The Luftwaffe gradually increased the frequency of attacks. German bombers also raided targets as far north as Liverpool during night hours.James 2000, pp. 49–62.

By 12 August, German air strength had reached acceptable levels. After bringing its serviceable rates up, the Luftwaffe began Adlertag with 71 percent of its bomber force, 85 percent of its Bf 109 units, and 83 percent of its Bf 110 units operational.Murray 1983, p. 51.

The first major raid inland and against RAF airfields came on 12 August. RAF Hawkinge, Lympne, Manston and radar stations at Pevensey, Rye and Dover were to be destroyed. Portsmouth docks were also targeted.James 2000, pp. 63–64, 70. The results of the raids were mixed. The radar station at Ventnor was badly damaged and others targeted were also damaged, but not destroyed. All but Ventnor were in working order by the following morning. Attacks against the harbour and RAF stations failed to destroy them. Though none were in full working order at the end of the day, all were back in action the following morning. Unknown to German intelligence, Lympne itself was not even an operational station. This sort of intelligence blunder contributed to the failure of Adlertag.James 2000, p. 70.

Overall, the Germans had not achieved a degree of success commensurate with their exertions.James 2000, p. 71.

Luftwaffe preparations

Intelligence

Faulty intelligence was the component that was mostly responsible for the failure of Adlertag. While the gap between the British and Germans was not yet wide in this regard, the British were starting to gain a decisive lead in intelligence. The breaking of the Enigma machine and poor Luftwaffe signals discipline allowed the British easy access to German communications traffic. The impact of Ultra on the Battle of Britain is a matter of dispute, with Official Histories claiming there was no direct impact. Whatever the truth, Ultra, and the Y service in particular, gave the British an increasingly accurate picture of German order of battle deployments.Murray 1983, p. 47.

Joseph "Beppo" Schmid was commander of the Luftwaffe's Military Intelligence Branch (Abteilung 5 as Chief IC). Throughout this time, Schmid's reports made a series of errors. In July 1940, Schmid grossly overestimated the strengths of the Luftwaffe and underestimated the RAF. The most serious mistakes were made concerning radar, airfield identification, and production sites. Schmid asserted that the number of operational airfields in southern England were severely limited; estimated that the British could produce only 180–330 fighters per month (the true figure was 496) and that figure would decrease, indicating that the RAF could not sustain a long battle of attrition. Schmid also claimed the command at all levels was rigid and inflexible, with fighters being tied to home bases. In his list of omissions, Schmid failed to mention the RAF maintenance and organisation operations, which put back damaged aircraft with rapid effect. He anticipated a short battle. Crucially, Schmid failed to mention radar at all.Bungay 2000, pp. 187–188.Hooton 1994, pp. 19–20.Ray 2009, pp. 46–47.

The lack of sustained and concentrated attacks on radar left it free to help direct the deployment of RAF units at opportune moments. Its continued warnings of incoming raids were a crucial benefit to Fighter Command. The Luftwaffe also had poor intelligence on the type of RAF airfields. It made repeated errors, often misidentifying airfields as Fighter Command bases, which turned out to belong to RAF Coastal Command and RAF Bomber Command. On Adlertag, most of the targets on the Luftwaffes list—if destroyed—would not have impaired Fighter Command in the slightest.Mason 1969, pp. 236–237.

Targets and order of battle

The following targets were chosen for attack on 13 August 1940:

+Attack on 13 August 1940 German bomber unit TargetKampfgeschwader 1 (KG 1)RAF Biggin Hillde Zeng, Stankey & Creek 2007 Vol 1, p. 14.Kampfgeschwader 76 (KG 76)de Zeng, Stankey & Creek 2007 Vol 2, p. 228.RAF Kenley RAF Debden/RAF Biggin Hillde Zeng, Stankey & Creek 2007 Vol 2, p. 225./ Other unknown targetsde Zeng, Stankey & Creek 2007 Vol 2, p. 236.Kampfgeschwader 2 (KG 2) Kampfgeschwader 3 (KG 3)RAF EastchurchAccording to de Zeng et al writes there is nothing published on KG 3; it was one of the most obscure bomber units, owing to the loss of most of its records at the end of the war.de Zeng, Stankey & Creek 2007 Vol 1, p. 48.Kampfgeschwader 53 (KG 53)RAF North Wealdde Zeng, Stankey & Creek 2007 Vol 1, p. 171.Erprobungsgruppe 210Kampfgeschwader 4 (KG 4)Unknown targets (lack of records)/some mine-laying operations in English Channelde Zeng, Stankey & Creek 2007 Vol 1, pp. 49–54.Kampfgeschwader 40 (KG 40)RAF DishforthKampfgeschwader 26 (KG 26)RAF Dishforthde Zeng, Stankey & Creek 2007 Vol 1, p. 75./Linton-on-OuseKampfgeschwader 30 (KG 30)RAF Driffieldde Zeng, Stankey & Creek 2007 Vol 1, p. 118.Kampfgeschwader 27 (KG 27)Ports of Bristol/Birkenhead/Liverpoolde Zeng, Stankey & Creek 2007 Vol 1, p. 104.Lehrgeschwader 1 (LG 1)de Zeng, Stankey & Creek 2007 Vol 2, p. 360.RAF Worthy Down/ Ports of Southampton, Portsmouth and surrounding airfieldsde Zeng, Stankey & Creek 2007 Vol 2, p. 266./RAF Detlingde Zeng, Stankey & Creek 2007 Vol 2, p. 370.Ward 2004, p. 105./Other unspecified operationsde Zeng, Stankey & Creek 2007 Vol 2, p. 354.Sturzkampfgeschwader 3 (StG 3)StG 3 was to take part. For unknown reasons it was removed from the order of battle on 13 August.de Zeng 2010, p. 100. Another source asserts that the unit had its missions cancelled owing to poor weather.Goss 2000, p. 79.Kampfgeschwader 51 (KG 51)RAF Biburyde Zeng, Stankey & Creek 2007 Vol 1, p. 155./Spithead harbourde Zeng, Stankey & Creek 2007 Vol 1, p. 146./Ventnor radar stationKampfgeschwader 54 (KG 54)Fleet Air Arm base Gosportde Zeng, Stankey & Creek 2007 Vol 1, p. 179./RAF Croydonde Zeng, Stankey & Creek 2007 Vol 1, p. 184. RAF FarnboroughBungay 2000, p. 208. RAF OdihamJames 2000, p. 74.Kampfgeschwader 55 (KG 55)Plymouthde Zeng, Stankey & Creek 2007 Vol 1, p. 195./Felthamde Zeng, Stankey & Creek 2007 Vol 1, p. 198./RAF Middle Wallopde Zeng, Stankey & Creek 2007 Vol 1, p. 193.Sturzkampfgeschwader 1 (StG 1)RAF WarmwellBungay 2000, p. 210./RAF DetlingWard 2004, p. 105.I., and II./Sturzkampfgeschwader 2 (StG 2)Sturzkampfgeschwader 77 (StG 77)RAF Warmwell/PortlandBungay 2000, p. 208.

RAF operational command