THE AVRO LANCASTER
A CRITICAL HISTORY
By Robert Hickox
Arguably one of the best heavy bombers of the Second World War, the Lancaster evolved from the twin-engined Manchester whose Rolls Royce Vulture engines were unreliable, although the wings and fuselage were of good design and strong.
It was therefore decided to retain the wings and fuselage in a stretched version with four Merlin engines that were powerful and reliable. This was an excellent combination, so that the Lancaster could carry a heavy bomb-load over a long distance at a reasonable speed and, if caught by German night fighters or searchlights, could dive and climb in a corkscrew fashion due to its structural strength to try and throw off these unwelcome visitors.
However, the Lancaster’s main weakness was poor defensive armament. Despite Bomber Command having had first-hand experience of German night fighter tactics, the Lancaster had no real optimisation for the night bombing role. Even though the primary threat from night fighters was almost certain to come from behind or below, two-thirds of the Lancaster’s defensive armament was oriented towards the forward and upper arcs which, in the dark, would be most unlikely directions of attack due to lack of visibility and high closing speeds, which would be almost suicidal directions from which to make an attack in the dark. No significant analysis about likely threats or lessons learned about night-fighting were incorporated into the Lancaster’s design, although individual squadrons sometimes tried to overcome the lack of ventral defensive armament in an ad hoc fashion in an attempt to deter the German night fighters, which would soon learn to ruthlessly exploit this blind spot from below. This equally applied to the Halifax and Stirling heavy bombers.
The removal of the ventral turret that had been mounted on the Manchester in favour of the H2S radar installation was made with little concern for the impact on bomber survivability that is, the provision of a ventral defensive turret to defend against attacks from below. The continued use of 0.303in. machine guns for self-defense, when the twin-engined German night fighters were already known to be using 20mm cannon, was a glaring design flaw in an otherwise well-built aircraft. Each 20mm HE-M round had three times the blast effect of a standard HE round and a two-second burst or just 18-20 hits from these could bring down a Lancaster. The later incorporation of “Schrage Musik”, two 20mm cannon set at an upward angle, allowed the German night fighters to format below the bomber unseen and then blast away with their two 20mm cannon, usually setting the bomber on fire or the wing would explode. Together with SN-2 air-to-air radar in the twin-engined night fighters and the RAF’s failure to realize the capabilities of both more than eight months after the night fighters began using them, left the bombers virtually defenseless during the most intense phase of the night bombing of Germany from June 1943 to July 1944.
More Lancasters were shot down from below than from any other quarter, and this weakness was never adequately addressed. As the other heavy bombers including the Halifax, and in lesser numbers the Stirling, also lacked ventral defensive armament, the fact that so many bomber crew lost their lives on operations bears witness to this fatal weakness. Many hundreds, probably thousands of aircrew, who would have otherwise stood a better chance of survival, lost their lives in this way. There was a complete failure to make realistic operational assessments in the critical early days of the Lancaster programme. Not enough effort was put into defensive measures and night navigation until the failure of the night bomber offensive became a real possibility due to unsustainable losses.
It has been stated with hindsight that aircraft coming up from below would not be very visible having their exhaust flames shrouded. However they would be more visible in plan form than those approaching from the rear, where the rear gunner would only have a frontal view of the attacking fighter. He would probably only be able to look down at a 45 degree angle and could not see anything approaching from below at a greater angle. A ventral gunner would have a downward view. He might see the glow from luminous cockpit instruments and the fighter might be silhouetted against light from the ground such as bombing fires. On balance, I consider that the work needed to add a ventral ball turret to Lancasters would have been worthwhile, for even the presence of defensive armament would discourage night fighters attacking from below unseen, and therefore saving lives.
It should have been possible that, in a time of war, the American Sperry ball turret, as fitted to their 8th Army Air Force B-17 bombers, could have been built under licence in this country and retro-fitted to all Lancasters as they came up for major engineering checks with, at the same time, removal of the nose and dorsal turrets to save weight, and their positions faired over. Crew members could have been reduced by two, which would also have saved lives. The ball turret could have been fairly easily accommodated between fuselage sections. Unfortunately, those in command wanted the H2S radar scanner in that position instead. The crews would have much preferred the ball turret to defend them from below, with 20mm cannon in the ball turret and the tail gun, to match the German night fighter armament.
The Lancaster B Mk.II was manufactured with Bristol Hercules radial engines due to a seemingly imminent shortage of Merlin engines Trials were successful, so that 300 B Mk.II Hercules-engined Lancasters were manufactured by Armstrong Whitworth. These were fitted with a Frazer Nash type ventral turret as “Gee H” was the primary navigation/blind bombing aid. Thus H2S was not carried leaving space for the ventral turret, which greatly reduced this mark of Lancaster’s vulnerability to German fighters equipped with ”Schrage Musik” upward firing cannon. But no more Lancasters were thus equipped as the shortage of Merlin engines did not transpire. An advantage of the Hercules air-cooled engine was its ability to withstand flak damage, while the liquid-cooled Merlins lost their coolant if hit and frequently caught fire. However the maximum ceiling of the Hercules-engined Lancasters with a full bomb load was less than with the Merlin. Therefore, after a limited production run, Merlins were again adopted. It was considered that the H2S look-down radar to improve navigation was more important than the Frazer Nash ventral turret, which the crews would have much preferred. But their concerns were not taken into account.
The Lancaster could carry the 4,000 lb “Cookie”, the 12,000 lb “Tallboy”, and the 22,000 lb “Grand Slam” bomb which could demolish bridges and viaducts by its shock wave. To carry this very large bomb, which was only used towards the end of the war, the Lancaster needed a modification to its bomb bay and bomb doors. It was the only British bomber that could carry this enormous bomb.
The Lancaster was also used in the Dams Raid where their bomb-bays had to be modified to carry the cylindrically-shaped bomb which had to be spun up before dropping from a certain height, speed, and distance from the dam. The reverse spin on the cylindrical bomb would enable it to bounce on the water surface a number of times and induce it to sink downwards when it hit the dam wall, where a water-pressure trigger would set it off at a certain depth. In this way, the two conventionally built wall-type dams were breached, the Mohne and the Eder, with the resulting destructive flood and disruption to German industrial production downstream from the breached dams. Unfortunately a camp of foreign slave workers was engulfed with high loss of life, and the damage to industry from the flood not as great as hoped, although rebuilding and increasing the defence of the dams took much manpower away from other projects. Although roughly half the attacking crews were shot down and killed, the mission was more of a propaganda victory than a destructive one, as industrial production in those areas inundated was soon able to resume. However, the raid helped to lift the morale of British civilians at a crucial point in the war.
The first RAF squadron to convert to the Lancaster was No. 44 Squadron RAF in early 1942. Lancasters flew 156,000 sorties and dropped 608,612 long tons (618,378 tonnes) of bombs between 1942 and 1945. Just 35 Lancasters completed more than 100 successful operations each, and 3,249 were lost in action. The most successful survivor completed 139 operations, and was scrapped in 1947.
At the end of 1942, there were nine squadrons of 150 Bf 110s and 36 Dornier Do.215/217s used as night fighters. In June 1943 during bombing raids on the Ruhr industrial area which was very heavily defended with anti-aircraft guns, the Nachtjagd (Night Fighter Force) destroyed one third of Bomber Command’s frontline strength, 1600 aircrew were killed or became prisoners and only 8 Bf.110s were lost in combat with 10 to other causes. This was a 30:1 ratio in Germany’s favour. A substantial number of these night fighters had received “Schrage Musik” armament and SN-2 Lichtenstein radar in Sept 1943, greatly increasing their lethality. At such a rate morale in Bomber Command would break long before that of German civilians.
A very destructive raid on Lubeck, where much of the building stock was of wooden construction and burned readily, preceded an attack on Hamburg in July 1943. Lancasters took part in this destructive raid when the initial use of “window”, short strips of tinfoil designed to mimic the wavelength of the German radar to give false indications and thoroughly mislead the defending night fighters. Thus the bombers were able to make two nights of unopposed raids on the city. It was a hot summer with everything tinder dry. As a result, a firestorm was created in the city centre, which sucked in oxygen as a high wind and temperatures rose to destructive levels. Many thousands were killed by the fires and in shelters, where the depleted oxygen levels meant they died unknowingly from breathing in carbon monoxide. The central area of Hamburg was completely destroyed. If other German cities could have been so devastated, the Germans would have been obliged to surrender, according to Albert Speer, Minister for Production, as the state infrastructure for the production and distribution of goods and services would have been destroyed.
Unfortunately, the Germans were excellent at finding solutions to British efforts to confuse their radars, and electronic countermeasures were rapidly put in place to negate this confusion, and such unopposed raids were no longer possible. An electronic countermeasures race to negate each other’s electronic advantage went on until the end of the war with no clear outright winner.
Other raids included that on Peenemunde, the rocket research and development facility, which was partially successful, although a number of bombers were shot down. Many workers on the project were killed. But how much it delayed the development of this potent weapon is difficult to say, as many of the top scientists escaped injury and any research facilities damaged could soon be repaired.
Certain raids, such as that on Nuremburg at the end of March 1944, went badly wrong when the bomber stream did not follow an indirect route to confuse the defending fighters as to the target, but flew straight to it. There was a full moon which increased visibility of the bombers to the night fighters. The Luftwaffe signal service identified radio and H2S radar emissions while the raid was still over England which gave the Nachtjagd plenty of advanced warning. The defending fighters were waiting for them and were able to shoot down the greatest proportion of bombers to the total force in the entire night bombing war, 95 bombers, 64 of which were Lancasters, out of a total of 795, 12% of the raiding force. Even worse, most of the raid missed Nuremburg completely and inflicted only token damage. Further losses in April 1944 amounted to 112 Lancasters.
In 1944 a series of Lancaster attacks using “Tallboy” bombs against the German battleship Tirpitz, first disabled and later sank the ship whilst it was sheltering in a Norwegian fjord. Due to a delay in relaying the information of bombing raid to the nearest fighter airfield, all the Lancasters bombed the ship which turned over trapping many sailors, and departed without loss before any of the fighters turned up. Their delay may not have been an accident as the German radar operator, the first to see the approach of the bombers from inland, may have been against the Nazi regime and have delayed his report to the defending fighter airfield on purpose. Anyway, for the bombers, it was a lucky escape from the fighters.
RAF Lancasters also dropped food into the Holland region of the occupied Netherlands, which had been by-passed by the allied armies to feed people who were in danger of starvation towards the end of the war. 20,000 Dutch civilians had already died of starvation and the Germans there could do nothing to alleviate this situation as they were short of food themselves. The aircraft involved were from 1, 3, and 8 Groups, and consisted of 145 Mosquitos and 3,156 Lancasters, flying between them a total of 3,298 sorties. Without these food supply flights, thousands more would have died from starvation.
A total of 6924 Lancasters were built between Oct 1941 and May 1945 of which 3249 were lost in action and 1005 in training or non-combat accidents. A total of 58% were therefore destroyed, the highest percentage loss of any RAF aircraft. Lancaster production represented 12 % of the UK’s military expenditure. Unfortunately, Lancasters proved unable to inflict sufficient damage on Germany to be a decisive war winner, and approx.25,000 aircrew died between mid-1942 and mid-1944 on Lancasters and another 25,000 on other bombers, the Luftwaffe shooting down at least half the bombers built each month.
A development of the Lancaster was the Avro Lincoln bomber, initially known as the Lancaster IV and Lancaster V. These two marks became the Lincoln B1 and B2 respectively. A civilian airliner based on the Lancaster, the Lancastrian, initiated airline service from the new London (Heathrow) Airport in 1946 for B.S.A.A. (British South American Airways), whose managing director was Air Vice Marshal Don Bennett, the creator of the Pathfinders. Other developments were the York, a square-bodied transport and cargo aircraft and, via the Lincoln, the Shackleton, which continued in airborne early warning and maritime patrol service up to 1992.
AVM Harris has tended to emphasize the importance of the destructive capabilities of the Lancaster to the detriment of other considerations such as crew protection. Thus a ventral gun turret was not considered as important as a radar which could pick out coastlines, rivers and built up areas through cloud and the darkness, despite the Main Bomber Force being able to rely on flares dropped by the elite Pathfinder Force to mark the target from 1943 onwards, and despite the wishes on the crews for a ventral gun turret. Thus losses were much greater than they need to have been. This is my conclusion from what I have said above and there are those who may dispute this. But it seems to me to follow on from what I have read and written.
Obviously Harris’ primary mission was to destroy the German war machine at its source so that maximum bomb load was of the greatest importance. With more planning for the design of a night bomber when first conceived, it would appear to me that this destruction could have been achieved with the incorporation of better crew defence and protection. Also, in the last year of the war, Harris could have replaced his heavy bomber force with the Light Night Striking Force composed of De Havilland Mosquitos which could fly faster than the defending fighters but with a lesser bomb load, and thus save lives. Instead he chose to retain his heavy bomber force. Despite this, the brave heavy bomber crews battled on night after night against the odds, which were stacked against them on surviving a tour of 30 operations.
German Night Fighter Aces of World War 2 – Jerry Scutts (Osprey)
Bf 110 vs Lancaster 1942-45 – Robert Forczyk (Osprey)
Le Fana de L’Aviation – Les raids de la RAF sur Berlin en 1943-44: Patrick Facon Wikipedia (Google)