Adlertag

For the Luftwaffe, 13 August 1940 was “Eagle Day” (Adlertag), the first day of Operation Eagle Attack (Unternehmen Adlerangriff), which was meant to destroy Britain’s fighter force within days or weeks and open the way for an invasion of Britain. That day German aircraft flew close to 1,500 sorties and bombed airfields, ports and factories from Kent to Dorset. Yet the day began with a blunder: in the morning the high command called off the attack because of the weather, but not every unit received the order, and those that did fly mostly struck airfields that did not belong to Fighter Command. In the evening the Germans proclaimed a great success, although the British fighter force had lost barely a dozen or so aircraft in the air. The British date the Battle of Britain from 10 July, but for the Germans, and for some German historians, the real “air battle for England” (Luftschlacht um England) began on 13 August.

The order to destroy the RAF

On 16 July Adolf Hitler ordered preparations for a landing in Britain, Operation Sea Lion. The precondition for crossing the Channel was command of the air, without which the barges carrying the troops could be protected neither from British aircraft nor from the ships of the Royal Navy. On 1 August, in Directive No. 17, Hitler ordered the Luftwaffe to overpower the English air force with all the forces at its command in the shortest possible time, attacking above all the aircraft themselves, their airfields, ground organisation and the aircraft industry. The Luftwaffe could begin the intensified air war from 5 August, its start depending on the weather.

The Commander-in-Chief of the Luftwaffe, Reichsmarschall Hermann Göring, was certain of victory. German air intelligence, headed by Oberst Josef “Beppo” Schmid, estimated in July that the British fighter force had around 900 aircraft, and put its capacity to replace losses far below what British factories were actually producing. Schmid’s report all but ignored radar and failed to understand how the British air defence command system worked. According to post-war studies, it was assumed that the RAF’s fighters in southern England could be smashed within four days and the rest of the British air force within a few weeks. On 6 August Göring discussed the plan of attack with his air fleet commanders at his residence, Carinhall. Field Marshal Albert Kesselring’s Luftflotte 2 was to operate from Belgium and northern France against Kent, the Thames Estuary and the London area; Field Marshal Hugo Sperrle’s Luftflotte 3 from Normandy and Brittany against Hampshire, Dorset and the west; while General Hans-Jürgen Stumpff’s Luftflotte 5 in Norway and Denmark was to be ready to strike at the north of England.

Eagle Day was first set for 10 August, but bad weather persisted over the Channel and the date kept slipping. The fighting did not stop: on 8 August the Luftwaffe shattered convoy CW 9 (“Peewit”) off the Isle of Wight, and on 11 August it carried out a heavy raid on the naval base at Portland. Only the forecast for 13 August induced Göring to give the order. In his often-quoted order of the day he told his airmen that within a short time they would wipe the British air force from the sky.

12 August: the strike at the radars

A day earlier the Germans had tried to blind the British defences. On the morning of 12 August a special trials unit, Hauptmann Walter Rubensdörffer’s Erprobungsgruppe 210, flying Messerschmitt Bf 110s and Bf 109s adapted for bombing, attacked four Chain Home radar stations on the coast of Kent and Sussex: at Dover, Rye, Pevensey and Dunkirk near Canterbury. The bombs wrecked huts, cut power cables and put some stations out of action for a few hours, but did not bring down the tall aerial masts. Most of the radars were working again the same day or the following morning. At midday a dozen or so Junkers Ju 88 bombers of KG 51, flying as part of a large raid on Portsmouth, bombed the station at Ventnor on the Isle of Wight and badly damaged it. Sources differ on how long it was out of action, from three days to more than a week. The British covered the gap with a signal from a substitute transmitter, so that the Germans would think the station was working.

The same day the Germans bombed the forward airfields on the Kent coast: Manston, Lympne and Hawkinge. The landing grounds were pitted with craters and hangars and buildings destroyed, but the next day fighters were again taking off from Manston and Hawkinge. Lympne, which suffered most, served only as an emergency airfield anyway. On 12 August the Luftwaffe lost about thirty aircraft, the RAF about twenty. Most important, however, was the conclusion the Germans drew from that day: since the radar stations had come back on the air so quickly, they decided that they were hard to destroy, and in the following weeks attacked them only sporadically. It was one of the Luftwaffe’s gravest mistakes of the entire battle.

Morning: Fink flies alone

On the morning of 13 August low cloud and mist hung over the Channel. Göring called off the morning attack and postponed its start until the afternoon. The order, however, did not reach everyone. At around 5 a.m. more than seventy Dornier Do 17 bombers of KG 2 took off, led by their commander, Oberst Johannes Fink – the same man who in July had directed the attacks on convoys as “Kanalkampfführer”. Over the Channel they were to be joined by twin-engined Messerschmitt Bf 110 fighters of Oberstleutnant Joachim-Friedrich Huth’s ZG 26. Huth’s unit had received the recall, and since he could not talk to the bombers by radio – the two units used different frequencies – he tried to turn them back by performing manoeuvres in front of their formation. Fink failed to understand the signals, or chose not to, and flew on without escort.

Not everything went right for the British either. Radar picked up the formations, but in the cloud the ground observers misjudged their course, and the fighters did not intercept the Dorniers before the target. At around 7 a.m. the bombers attacked the airfield at Eastchurch on the Isle of Sheppey in the Thames Estuary. They destroyed hangars, quarters and ammunition stores, and on the ground several Bristol Blenheim bombers and one Spitfire; a dozen or so people were killed, 14 to 16 according to different tallies. Eastchurch, however, belonged to RAF Coastal Command, not Fighter Command, and the airfield was operating again that same day. The German airmen reported having destroyed a dozen or more Spitfires on the ground, and for weeks afterwards Luftwaffe intelligence regarded Eastchurch as a fighter base and sent further raids against it.

On the way home the Dorniers were caught by Hurricanes and Spitfires from several squadrons, among them No. 74 Squadron, led by Adolph “Sailor” Malan, one of the RAF’s finest aces. KG 2 lost four or five bombers, and several others returned badly damaged. A furious Fink complained to his superiors that his men had been sent out without escort. It was not the only mishap that morning. The recall did not reach the headquarters of Luftflotte 3 in time at all, and its Ju 88s attacked airfields in inland Hampshire. Before noon more than twenty Bf 110s of Lehrgeschwader 1 (LG 1), which were to sweep away the fighters ahead of a bomber raid, flew over Portland even though the bombers had been recalled. They ran into Hurricanes and lost several aircraft. The morning attack was a fiasco and exposed the weakness of radio communications between German units.

Afternoon: the attack proper

At 2 p.m. the Luftwaffe received permission to begin the attack. From 3.30 p.m. successive raids by Luftflotte 3 came in over Hampshire and Dorset: dozens of Ju 88s of LG 1 and Junkers Ju 87 dive-bombers of StG 1, StG 2 and StG 77, escorted by Messerschmitts. Ahead of them flew a group of fighters intended to draw the British squadrons onto themselves, which merely alerted the defences earlier. No. 10 Group scrambled every fighter it had. Over Lyme Bay and Dorset the Spitfires of No. 609 Squadron caught a Staffel of Ju 87s from StG 2 and shot down six of its nine aircraft. StG 77 failed to find its target, Warmwell airfield, in the cloud and dropped its bombs at random.

The Ju 88s could not reach the airfields assigned to them and bombed the docks at Southampton. They destroyed warehouses and a cold store, and the fires were put out by nightfall. A few kilometres away, on the waterfront at Woolston, stood the Supermarine works, the main producer of Spitfires, but German intelligence did not consider it an important target and it survived until September. Bombs also fell on the airfield at Andover, which belonged to the bomber and training commands, and a few on Middle Wallop, one of No. 10 Group’s sector stations.

In the east, over Kent, Kesselring’s units struck. At about a quarter past five, Ju 87 dive-bombers of IV./LG 1, covered by Messerschmitt Bf 109s that strafed the airfield with their guns, attacked Detling near Maidstone. It was the bloodiest raid of the day. Bombs hit the operations block, the mess and the hangars, and according to British tallies some twenty aircraft burned on the ground, mainly Blenheims of No. 53 Squadron. The station commander, Group Captain Edward Meggs-Davis, was killed. The number of dead is given variously: the RAF’s own casualty lists speak of 24 airmen killed, while combined figures covering servicemen and civilians give 67 victims. Detling, like Eastchurch, belonged to Coastal Command, and its destruction did not weaken the fighter force. Dorniers of KG 3 bombed Eastchurch again, and bombs also fell on Rochester, where the Short Brothers works were building Stirling heavy bombers.

After dark nine Heinkels of Kampfgruppe 100, which specialised in night navigation along radio beams, flew to Castle Bromwich near Birmingham, where a great new Spitfire factory was going up. Only four crews found the target, and the dozen or so bombs they dropped damaged chiefly offices and the toolroom. Other German aircraft roamed over various parts of Britain that night without doing much damage.

That same day RAF Bomber Command suffered a tragedy of its own. Twelve Blenheims of No. 82 Squadron were sent in daylight against the airfield at Aalborg in occupied Denmark. One turned back; the other eleven were shot down by German flak and fighters.

Tally and boasts

On 13 August the Luftwaffe flew about 1,485 sorties, Fighter Command about 727. Exact losses vary from study to study. According to post-war tallies the Germans lost between nearly forty and 47–48 aircraft, and several dozen more returned damaged. Fighter Command lost thirteen or a few more fighters in combat, and three or four pilots were killed. In addition the RAF lost eleven bombers over Aalborg and several dozen aircraft of various types destroyed on the ground, mostly bombers and trainers, with only the odd fighter among them.

Both sides overestimated their successes, as they did throughout the battle, because in the confusion of combat several pilots fired at the same aircraft and every puff of smoke from an engine was taken for a kill. The Air Ministry announced the destruction of 78 German machines. German airmen claimed some 70 Hurricanes and Spitfires and a dozen or so Blenheims shot down in the air, plus dozens of aircraft destroyed on the ground – several times more than the RAF actually lost. Such reports formed the basis of the assessments of Luftwaffe intelligence, which in the following weeks assured Göring that Fighter Command was down to a few hundred and then to a mere few dozen fighters. German propaganda bulletins, including the daily Wehrmacht report, presented Eagle Day as a crushing blow.

In reality the fighter force came through the day unscathed. Not one of the sector airfields of Air Vice-Marshal Keith Park’s No. 11 Group, from which the defence of London and south-east England was directed, was seriously hit. Of the airfields the Germans attacked, most belonged to Coastal Command, Bomber Command or the training organisation. The radar, damaged the day before, was working and gave the head of Fighter Command, Air Chief Marshal Hugh Dowding, what he needed most: time to scramble fighters only where they were needed. Knowing that the Germans would keep attacking, Dowding was all the more careful to husband his pilots and kept the squadrons in the north in reserve.

Why the attack failed

Eagle Day laid bare weaknesses that were to tell throughout the campaign. The Luftwaffe lacked good intelligence: it did not know which airfields were fighter bases, did not understand the role of radar and of the operations rooms at Bentley Priory and at group headquarters, overrated its own victories and underestimated British aircraft production. Its command was also unable to concentrate its effort on a single objective, and the attacks were dispersed over ports, factories and random airfields. On top of this came the limitations of its equipment: the Messerschmitt Bf 109 had fuel for at most a quarter of an hour or so of combat over England, the Bf 110 proved insufficiently manoeuvrable against single-engined fighters, and the Ju 87, so fearsome in Poland and France, suffered heavy losses as soon as Spitfires and Hurricanes got at it. The British were fighting over their own territory, and a British pilot who was shot down and survived was often flying again the same day, whereas a German one went into captivity.

Place in the war

It is often written that on 13 August Göring launched a two-week offensive against the airfields. In fact the attacks on airfields went on, with a break of several days caused by the weather in the second half of August, for more than three weeks, until 6 September, and they were not planned to last for a set period: they were to continue until the RAF ceased to exist. Two days after Eagle Day, on 15 August, the Luftwaffe struck with all three air fleets at once, including from Norway, and suffered its heaviest losses of the whole battle. On 18 August it attacked the sector stations at Kenley and Biggin Hill, and from 24 August it concentrated on No. 11 Group’s airfields around London, putting Fighter Command in its most difficult position. The Polish fighter squadrons, Nos. 302 and 303, formed in July and August, were still training at the time; they went into action in the second half of August.

On 7 September Göring turned his bombers against London, which gave the RAF’s airfields a respite. After the great battle over the capital on 15 September it became clear that the Luftwaffe would not win command of the air, and on 17 September Hitler postponed the invasion. Eagle Day, meant to be the beginning of the end of the British air force, thus went down in history as an example of how poor intelligence, muddled command and belief in one’s own boasts can squander numerical superiority. The British remember it as one of many hard days of the Battle of Britain; in Germany it was for many years regarded as the battle’s beginning.