Battle of Britain in the Words of Air Chief Marshal Hugh Dowding
Part 3 - Aircraft and Tactics
RAF Fighter Aircraft
I must now give a brief account of the characteristics of the aircraft commonly employed on both sides. As regards the fighter types available in the Command, the bulk of the force consisted of Hurricanes and Spitfires; the former were beginning to be outmoded by their German counterparts. They were comparatively slow and their performance and manoeuvrability were somewhat inadequate at altitudes above 20,000 ft. The Spitfires were equal or superior to anything which the Germans possessed at the beginning of the Battle.
In the aforementioned publication entitled The Battle of Britain, issued by the Air Ministry, the speed of the Hurricane is seriously over-rated at 335 m.p.h. I carried out a series of trials to obtain the absolute and comparative speeds of Hurricanes and Spitfires at optimum heights. Naturally the speeds of individual aircraft varied slightly, but the average speed of six Hurricanes came out at about 305 m.p.h.
The Hurricanes and Spitfires had bullet-proof windscreens and front armour between the top of the engine and the windscreen. They also had rear armour directly behind the pilot, which was previously prepared and fitted as soon as we began to meet the German fighters. The early adoption of armour gave us an initial advantage over the Germans, but they were quick to imitate our methods. While German aircraft remained unarmoured, I think it is now generally agreed that the single-seater multi-gun fighter with fixed guns was the most efficient type which could have been produced for day fighting. The Defiant, after some striking initial successes, proved to be too expensive in use against fighters and was relegated to night work and to the attack of unescorted bombers. It had two serious disabilities; firstly, the brain flying the aeroplane was not the brain firing the guns: the guns could not fire within 16 degrees of the line of flight of the aeroplane and the gunner was distracted from his task by having to direct the pilot through the communication set. Secondly, the guns could not be fired below the horizontal, and it was therefore necessary to keep below the enemy. When beset by superior numbers of fighters the best course to pursue was to form a descending spiral, so that one or more Defiants should always be in a position to bring effective fire to bear. Such tactics were, however, essentially defensive, and the formation sometimes got broken up before they could be adopted. In practice, the Defiants suffered such heavy losses that it was necessary to relegate them to night fighting, or to the attack of unescorted bombers.
The innovative but heavy Boulton-Paul Defiant was withdrawn from daylight operations following the tragedy of 141 Squadron on 19 July 1940, when six out of its nine Defiants were shot down in fighter-vs-fighter combat. As shown in the text, Dowding was very well aware about combat experiences with this aircraft and supported the decision of its removal from first-line strength. [Crown Copyright]
The Blenheim was also unsuitable for day-time combat with fighters, owing to its low speed and lack of manoeuvrability.
One Squadron of Gladiators was still in use in the Command. As explained above, the organisation of No. 10 Group was not complete, and there was no large aerodrome close enough to Plymouth to allow of direct protection being given to that town and to the Dockyard at Devonport. A squadron of Gladiators was therefore located at a small aerodrome called Roborough in the immediate vicinity. The Gladiators, though slow by modern standards, were very manoeuvrable, and had given good results in Norway by deflection shooting in the defence of fixed objectives, where the bombers could not avoid the Gladiators if they were to reach their targets.
Some American single-seater aircraft were in Great Britain, but the types then available were deficient in performance and fire power and were not employed to any material extent.
The Whirlwind raised high hopes in some quarters. It claimed a very high top speed and carried 4 cannon guns. It had, however, a totally inadequate service ceiling (about 25,000 ft.) and a poor performance at that altitude. It also suffered from a continuous series of teething troubles, and the single Squadron equipped with this type was never fit for operations in my time.
Armament
A great deal of discussion took place before and in the early stages of the war as to the best method of harmonisation of the guns of an 8-gun fighter: that is to say the direction, in relation to the longitudinal axis of the aircraft, in which each gun should be pointed in order to get the best results.
There were three schools of thought. One maintained that the lines of fire should be dispersed so that the largest possible "beaten zone" might be formed and one gun (but not more than one) would always be on the target. The second held that the guns should be left parallel and so would always cover an elongated zone corresponding with the vulnerable parts of a bomber (engines, tanks and fuselage). The third demanded concentration of the fire of all guns at a point.
Arguments were produced in favour of all three methods of harmonisation, but in practice it was found that concentration of fire gave the best results. Guns were harmonised so that their lines of fire converged on a point 250 yards distant: fire was therefore effective up to about 500 yards, where the lines of fire had opened out again to their original intervals after crossing at the point of concentration.
It was very desirable to get data as to the actual ranges at which fire effect had been obtained. The reflector sight contained a rough range-finder which the range of an aircraft of known span could be determined if it was approached from astern, but, in spite of this, pilots, in the heat of action, generally underestimated the ranges at which they fired.
Cinema guns, invaluable for training purposes, were used in combat also; and many striking pictures were obtained, from which valuable lessons were learned.
The types of ammunition used in the guns varied during the course of the Battle. It was necessary to include some incendiary ammunition, but the type originally available gave a distinct smoke-tracer effect. Now tracer ammunition in fixed guns at any but very short range gives very misleading indications, and I wished pilots to use their sights properly and not to rely on tracer indications. (The above remarks do not apply at night, nor to free guns, where tracer is essential for one of the methods taught for aiming.)
During the Battle, de Wilde ammunition became available in increasing quantities. This was an incendiary ammunition without any flame or smoke trace, and it was extremely popular with pilots, who attributed to it almost magical properties. 8-gun Fighters, of course, were always liable to be sent up at night, and it was therefore desirable to retain some-of the older types of incendiary bullets. These were preferred to the "tracer" proper, which gave too bright a flame at night.
A typical arrangement, therefore, was: old-type incendiary in the 2 outer guns, de Wilde in one gun while supplies were limited, Armour piercing in 2 guns, and ball in the other 3.
Altitude Performance
Increasingly throughout the Battle had the importance of a high ceiling been manifested. It is by no means necessary that every fighter shall have its best performance at stratospheric heights; any such policy would result in a loss of performance at lower altitude, and we must never lose sight of the basic principle that the fighter exists for the purpose of shooting down bombers, and that its encounters with other fighters are incidental to this process.
There are, nevertheless, arguments for giving to a percentage of fighters a ceiling (determinable by specific physiological tests) above which no enemy can climb without the use of pressure cabins. Just as the "weather gauge" was often the determining factor in the tactics of sailing ships, so the " height gauge" was often crucial in air combat. Exhaust-driven turbo-superchargers have certain advantages over gear-driven blowers at great height, and should be considered for adoption in spite of their disadvantages.
Enemy Aircraft
It is very difficult to give any kind of concise description, of the types of enemy aircraft used during the Battle. The Germans, while adhering to broad standard types, were continually modifying and improving them by fitting more powerful engines and altering the armament. The original Messerschmitt 109, for instance, had a performance comparable with that of the Hurricane, but the latest type could compete with the Spitfire, and had a better ceiling. Some of them had 4 machine guns and others had 2 machine guns and 2 cannon. Some of them were fitted to carry bombs and some were not.
The Messerschmitt 110 was a twin-engined fighter designed primarily for escorting bombers and used also as a fighter-bomber. It was somewhat faster than the Hurricane, but naturally much less manoeuvrable than the single-engined types. Its usual armament was 2 fixed cannon and 4 machine guns firing forward, and one free machine gun firing to the rear. Our pilots regarded it as a less formidable opponent than the later types of Me 109.
The Heinkel 113 Fighter made its appearance in limited numbers during the Battle. It was a single seater, generally resembling the Me 109. Its main attributes were high performance and ceiling, so that it was generally used in the highest of the several layers in which attacking formations were usually built up.
The Junkers 87 was a single-engined dive bomber. With top speed well under 250 m.p.h., its performance was low. It had 2 fixed machine guns firing forward and one free gun firing to the rear. When it was able to operate undisturbed by fighters it was the Germans' most efficient bomber against land or sea targets owing to the great accuracy with which it dropped its bombs; but when it was caught by fighters it was nothing short of a death-trap, and formations of Ju 87's were practically annihilated on several occasions.
The Heinkel 111 and the various types of Dornier (17, 17 Z and 215) constituted the main element of the German striking force. They were twin-engined aircraft and were generally similar, although the former was slightly the larger. Their speed was something over 250 m.p.h., and their armament consisted normally (but not always) of 4 free machine guns firing backwards and one firing forwards. Their radius of action varied with tankage and bomb load, but, if necessary, all objectives in England and Northern Ireland could be reached from aerodromes in France.
The Junkers 88 was the most modern of the German bombers. It also was a twin-engined type with a performance of about 290 m.p.h. Its armament was generally similar to that of the He 111 and the Dormers and it had a slightly longer range. It could be used on occasions as a dive bomber and, though probably somewhat less accurate than the Ju 87, was much less vulnerable owing to its superior performance and armament.
German Tactics
It has been estimated that the Germans sent over, on an average throughout the Battle, four fighters to each bomber or fighter-bomber, but any such estimate must be very rough.
I must emphasise, throughout, the extreme versatility of the German methods both in the timing and direction of their attacks, and in the tactical formations and methods employed.
They enjoyed the great advantage of having a wide front from which attacks could be delivered. First a blow would be delivered from Calais, perhaps against London; then after a carefully-timed interval, when 11 Group Fighters might be expected to be at the end of their petrol endurance, a heavy attack would be made on Southampton and Portland. Other attacks, after being built up to formidable dimensions, would prove to be only feints, and the bombers would turn away before reaching coast of England, only to return again in half an hour, when the fighters, sent up to intercept them, were landing.
Time-honoured methods of escort were at first employed. A strong fighter formation would fly a mile or so behind and above the bombers. When the Germans found that our fighters could deliver a well-timed attack on the bombers before the fighters could intervene, or when our fighters attacked from ahead or below, each move was met by a counter-move on the part of the Germans, so that, in September, fighter escorts were flying inside the bomber formation, others were below, and a series of fighters stretched upwards to 30,000 feet or more.
One Squadron Leader described his impressions of the appearance of one of these raids; he said it was like looking up the escalator at Piccadilly Circus.
Utilisation of British Forces
I must pay a very sincere tribute to the Air Officer Commanding No. 11 Group, Air Vice-Marshal K. R. Park, C.B., M.C., D.F.C., for the way in which he adjusted his tactics and interception methods to meet each new development as it occurred.
Tactical control was, as has already been stated, devolved to the Groups; but tactical methods were normally laid down by Command Headquarters. During periods of intense fighting, however, there was no time for consultation, and Air Vice-Marshal Park acted from day to day on his own initiative. We discussed matters as opportunity offered. He has reported on the tactical aspects of the Battle in two very interesting documents, which are, however, too long to reproduce here.
A close liaison was kept between Nos. 10 and 11 and 12 Groups. It sometimes happened that, in the heaviest attacks, practically all 11 Group Fighters would be in the air. 11 Group would then ask 12 Group to send a formation from Duxford to patrol over the aerodromes immediately East of London so that these might not be attacked when defenceless.
Mutual help was also arranged between Nos. 10 and 11 Groups. When Portsmouth was attacked, for instance, No. 10 would help No. 11 Group, and vice versa when the attack was on Portland or some Convoy to the West of the Isle of Wight.
It will be observed that, at the end of the second phase of the Battle, the power of reinforcing by complete units had substantially disappeared. We still possessed an effective reserve of trained pilots, but they could be made available only by stripping the squadrons which were not engaged in the South and South- East of England.
The effective strength of the Command was running down, though the fact was not known to the public, nor, I hoped, to the Germans. They for their part must certainly be feeling the effect of their heavy losses, but there was very little indication of any loss of morale, so far as could be seen from a daily scrutiny of the examinations of prisoners of war. Our own pilots were fighting with unabated gallantry and determination.
The confidence of the German High Command probably received something of a shock about this time. The sustained resistance which they were meeting in South-East England probably led them to believe that fighter squadrons bad been withdrawn, wholly or in part, from the North in order to meet the attack. On the 15th August, therefore, two large raids were sent, one to Yorkshire and one to Newcastle. They were escorted by fighters. The distance was too great for Me. 109s, but not for Me. 110s.
If the assumption was that our fighters had been withdrawn from the North, the contrary was soon apparent, and the bombers received such a drubbing that the experiment was not repeated. I think that this incident probably had a very depressing influence on the outlook of the German High Command.
As I have said, our own pilots were fighting with the utmost gallantry and determination, but the mass raids on London, which were the main feature of the third phase of the Battle, involved a tremendous strain on units which could no longer be relieved as such. Some squadrons were flying 50 and 60 hours per day.
Many of the pilots were getting very tired. An order was in existence that all pilots should have 24 hours' leave every week, during which they should be encouraged to leave their station and get some exercise and change of atmosphere: this was issued as an order so that the pilots should be compelled to avail themselves of the opportunity to get the necessary rest and relaxation. I think it was generally obeyed, but I fear that the instinct of duty sometimes overrode the sense of discipline. Other measures were also taken to provide rest and relaxation at stations, and sometimes to find billets for pilots where they could sleep away from their aerodromes.
Squadron Command in the Air
Some of our worst losses occurred through defective leadership on the part of a unit commander, who might lead his pilots into a trap or be caught while climbing by an enemy formation approaching out of the sun. During periods of intense activity promotions to the command of fighter squadrons should be made on the recommendation of Group Commanders from amongst Flight Commanders experienced in the methods of the moment. If and when it is necessary to post a Squadron Leader (however gallant and experienced) from outside the Command, he should humbly start as an ordinary member of the formation until he has gained experience. Only exceptionally should officers over 26 years of age be posted to command Fighter squadrons.
The experience of the Battle made me a little doubtful if the organisation of a squadron into two Flights, each of two Sections of 3 aircraft, was ideal. It was, of course, undesirable to make any sweeping change during the Battle, and I relinquished my Command shortly after its termination; but the weakness lay in the Section of 3 when it became necessary to break up a formation in a dogfight The organisation should allow for a break up into pairs, in which one pilot looks after the tail of his companion. A Squadron might be divided into 3 Flights of 4 (which would limit the employment of half-squadrons), or it might consist of 2 Flights of 8, each comprising 2 Sections of 4. This latter suggestion would upset standard arrangements for accommodation.
The matter is not one which can be settled without consultation with various authorities and branches of the Air Ministry. I therefore merely raise the point without making any definite recommendation.
A vic of Spitfires in line astern. This three-aircraft formation formed a nucleus of RAF fighter tactics in the air which turned out to pose many problems. Its major weakness was that the aircraft, when attacked, could not split in pairs, making mutual protection in combat impossible. The choice of 3-aircraft section, however, was deeply rooted in the organisational structure of the RAF fighter squadrons, and this fact largely prevented the rapid change even at the time when its disadvantages became well-known. [Crown Copyright]
The Big Wing Considerations
During the third phase of the Battle the problem arose, in an acute form, of the strength of fighter formations which we should employ. When time was the essence of the problem, two squadrons were generally used by A.V.M. Park in No. 11 Group. He had the responsibility of meeting attacks as far to the Eastward as possible, and the building up of a four-squadron formation involved the use of a rendezvous for aircraft from two or more aerodromes. This led to delay and lack of flexibility in leadership.
On the other hand, when No. 12 Group was asked to send down protective formations to guard the aerodromes on the Eastern fringe of London, it was often possible to build up big formations, and these had great success on some occasions, though by no means always.
Because a similar situation may well arise in future, I think that it is desirable to enter into some detail in this connection.
I may preface my remarks by stating that I am personally in favour of using fighter formations in the greatest strength of which circumstances will permit. In the Dunkerque fighting, where we could choose our time and build up our formations on the outward journey, I habitually employed four-squadron formations as a preferable alternative to using two-squadron formations at more frequent intervals; but, during the attacks on London, the available strength of fighters did not admit of this policy, nor was time available.
Quoting from Air Vice-Marshal Park's report: "The general plan adopted was to engage the enemy high-fighter screen with pairs of Spitfire squadrons from Hornchurch and Biggin Hill half-way between London and the coast, and so enable Hurricane squadrons from London sectors to attack bomber formations and their close escort before they reached the line of fighter aerodromes East and South of London. The remaining squadrons from London sectors that could not be despatched in time to intercept the first wave of the attack by climbing in pairs formed a third and inner screen by patrolling along the lines of aerodromes East and South of London. The fighter squadrons from Debden, Tangmere, and sometimes Northolt, were employed in wings of three or in pairs to form a screen South-East of London to intercept the third wave of the attack coming inland, also to mop up retreating formations of the earlier waves. The Spitfire squadrons were redisposed so as to concentrate three squadrons at each of Hornchurch and Biggin Hill. The primary role of these squadrons was to engage and drive back the enemy high-fighter screen, and so protect the Hurricane squadrons, whose task was to attack close escorts and then the bomber formations, all of which flew at much lower altitude."
I think that, if the policy of big formations had been attempted at this time in No. 11 Group, many more bombers would have reached their objectives without opposition.
Air Vice-Marshal Park also quotes the results of the ten large formations ordered from Duxford into No. 11 Group in the last half of October, when the Germans were employing fighter types only. Nine of these sorties made no interception, and the tenth destroyed one Me. 109.
Estimation of Casualties
The decisive features of the Battle were: the ratio of casualties incurred by ourselves and the Germans, and the ratio of casualties to the numbers actively employed on both sides.
As regards our casualties, we generally issued statements to the effect that we lost " x" aircraft from Which " y " pilots were saved. This did not of course mean that " y " pilots were ready immediately to continue the Battle. Many of them were suffering from wounds, burns or other injuries which precluded their return to active flying temporarily or permanently.
It might also be assumed that all German crews who were in aircraft brought down during the Battle, were permanently lost to the Luftwaffe because the fighting took place on our side of the Channel. Such an assumption would not be literally true, because the Germans succeeded in rescuing a proportion of their crews from the sea by means of rescue boats, floats and aircraft which will be later described.
I must disclaim any exact accuracy in the estimates of enemy losses. All that I can say is that the utmost care was taken to arrive at the closest possible approximation. Special intelligence officers examined pilots individually after their combats, and the figures claimed are only those recorded as "certain". If we allow for a percentage of over-statement, and the fact that two or more fighters were sometimes firing at the same enemy aircraft without being aware of the fact, this can fairly be balanced by the certainty that a proportion of aircraft reported as "probably destroyed " or "damaged " failed to return to their bases. The figures, then, are put forward as an honest approximation. Judging by results, they are perhaps not far out.
The German claims were, of course, ludicrous; they may have been deceived about our casualties, but they know they were lying about their own.
I remember being cross-examined in August by the Secretary of State for Air about the discrepancy. He was anxious about the effect on the American people of the wide divergence between the claims of the two sides. I replied that the Americans would soon find out the truth; if the Germans' figures were accurate they would be in London in a week, otherwise they would not.
Our estimate of German casualties, then, may be taken as reasonably accurate for practical purposes; but our estimates of the strength in which attacks were made is based on much less reliable evidence. The radio-location system could give only a very approximate estimate of numbers and was sometimes in error by three or four hundred per cent. This is no reflection on the system, which was not designed or intended to be accurate in the estimation of considerable numbers; moreover, several stations were suffering from the effects of severe bombing attacks. As the average height of operations increased, the Observer Corps became less and less able to make accurate estimates of numbers, and, in fact, formations were often quite invisible from the ground.
Even the numerical estimates made by pilots who encountered large formations in the air are likely to be guesswork in many instances. Opportunities for deliberate counting of enemy aircraft were the exception rather than the rule.
Although secret intelligence sources supplemented the information available, it is possible that on days of heavy fighting complete formations may have escaped recorded observation altogether.
This is unfortunate, because it is obviously of the greatest importance to determine the relative strengths of the attack and the defence, and to know the ratio of losses to aircraft employed which may be expected to bring an attack to a standstill in a given time. History will doubtless elucidate the uncertainty, but perhaps not in tune for the information to be of use in the present war.
My personal opinion is that, on days of slight activity, our estimates are reasonably accurate, but that they probably err on the low side on days of heavy fighting when many and large formations were employed.