The Avro Lancaster: A British Second World War Heavy Bomber

The Avro Lancaster, a British heavy bomber from the Second World War, was designed and built by Avro alongside the Handley Page Halifax and the Short Stirling. All three aircraft were developed to meet the same specifications and served as four-engined heavy bombers adopted by the Royal Air Force (RAF) during that era.

The Lancaster's origins can be traced back to the Avro Manchester, a twin-engine aircraft developed in the late 1930s in response to the Air Ministry Specification P.13/36, which called for a medium bomber capable of worldwide use, carrying an internal torpedo, and performing shallow dive-bombing attacks. Evolving from the Manchester, which faced difficulties in service and was retired in 1942, the Lancaster was designed by Roy Chadwick and powered by four Rolls-Royce Merlins, with one version using Bristol Hercules engines. It entered service with RAF Bomber Command in 1942 and became the primary aircraft for night-time bombing campaigns during the strategic bombing offensive over Europe. With increasing production, it emerged as the main heavy bomber for the RAF, Royal Canadian Air Force (RCAF), and squadrons from other Commonwealth and European countries serving within the RAF, surpassing the popularity of the Halifax and Stirling, two other widely used bombers.

The Lancaster's extended bomb bay allowed it to carry the largest bombs employed by the RAF, including the 4,000 lb, 8,000 lb, and 12,000 lb "blockbusters," often supplemented with smaller bombs or incendiaries. Famously known as the "Lanc," it became one of the most extensively utilized night bombers during the Second World War, delivering a remarkable 608,612 long tons (618,378,000 kg) of bombs in 156,000 sorties. Its versatility led to its selection for equipping 617 Squadron and adapting it to carry the Upkeep "bouncing bomb," designed by Barnes Wallis for Operation Chastise, the daring attack on German dams in the Ruhr valley. Although primarily a night bomber, the Lancaster excelled in various roles, including daylight precision bombing. Some Lancasters were modified to carry the 12,000 lb Tallboy and later the 22,000 lb Grand Slam earthquake bombs, both designed by Wallis, making it the bomber with the largest payload during the war.

In 1943, a Lancaster was transformed into an engine test bed for the Metropolitan-Vickers F.2 turbojet. Subsequently, Lancasters were employed to test other engines, including the Armstrong Siddeley Mamba and Rolls-Royce Dart turboprops, as well as the Avro Canada Orenda and STAL Dovern turbojets. After the war, the Lancaster was replaced as the primary strategic bomber of the RAF by the Avro Lincoln, a larger version of the Lancaster. The Lancaster then took on roles such as a long-range anti-submarine patrol aircraft (later replaced by the Avro Shackleton) and an air-sea rescue aircraft. Additionally, it served as a platform for photo-reconnaissance and aerial mapping, a flying tanker for aerial refueling, and the Avro Lancastrian, a long-range, high-speed transatlantic passenger and postal delivery airliner. In March 1946, a Lancastrian of BSAA conducted the first scheduled flight from the new London Heathrow Airport.

Design Overview:

The Avro Lancaster, a British four-engined strategic bomber, played a crucial role as the RAF's primary heavy bomber during the latter stages of World War II. Its power came from four wing-mounted Rolls-Royce Merlin piston engines, each driving a 13 ft (4.0 m) diameter de Havilland Hydromatic three-bladed propeller. While not ideal, the Lancaster could manage the return journey on just two operational engines and travel short distances on a single engine.

Renowned aviation authors Brian Goulding and M. Garbett praised the Lancaster for its favorable flying characteristics, describing it as a near-perfect flying machine—fast for its size and incredibly smooth. Experienced Lancaster pilots were even able to outmaneuver Luftwaffe fighters in some instances.

Structurally, the Lancaster was built for strength and durability, designed to withstand damage from enemy interceptor aircraft and anti-aircraft fire. However, during its early service, some aircraft encountered structural failures and accidents due to exceeding design limits.

The Lancaster featured a mid-wing cantilever monoplane configuration with five main wing sections and a similarly divided fuselage, mostly covered with all-metal material, except for the fabric-covered ailerons. This sectional construction facilitated faster production as components were prepared separately and assembled later.

Equipped with retractable main undercarriage and fixed tailwheel, the Lancaster had a distinctive tail unit with large twin elliptical fins and rudders.

Despite its strengths, the Lancaster had some handling limitations. It had a tendency to dive deeply as speed increased, and longitudinal instability occurred at speeds above 200 mph (320 km/h).

Crew Accommodation:

The standard Lancaster crew consisted of seven members, each occupying specific positions within the fuselage. The bomb aimer, positioned in the nose, had two roles: operating the bombsight controls while lying prone on the floor, and manning the Frazer Nash FN5 nose turret with twin .303 in (7.7 mm) guns. However, the narrow escape hatch in the floor made it difficult to exit with a parachute.

The pilot and flight engineer occupied seats under the expansive canopy on the roof of the bomb bay, with the flight engineer's collapsible seat situated to the right of the pilot. The navigator faced portside with a chart table in front, equipped with necessary instruments for navigation. The wireless operator had radios mounted on the left-hand end of the chart table, while the mid-upper gunner, positioned behind the bomb bay, had a 360° view with two Browning .303 Mark IIs for defense.

The rear gunner, stationed in the tail turret, accessed his position through a small hatch at the back of the fuselage. However, the cramped space required him to hang his parachute on a hook inside the fuselage. Both the mid-upper and rear gunner's positions lacked heating, necessitating electrically heated suits to prevent hypothermia.

Armament:

The Lancaster's defensive armament initially included hydraulically operated turrets with machine guns mounted in the nose, tail, mid-upper, and underside. The mid-upper turret used a cam-operated interrupter to prevent firing on the aircraft itself.

Later, Freeman Dyson proposed reducing the Lancaster's defensive armament to increase speed and decrease human losses when aircraft were shot down. However, this proposal was not adopted, as night fighters of the time could still intercept the Lancaster.

The nose turret, known as the FN-5A, remained mostly unchanged throughout the Lancaster's service life. The ventral (underside) FN-64 turret proved ineffective and was replaced with other experimental mounts, including those for .50 in (12.7 mm) machine guns or 20 mm (0.79 in) cannons.

The tail turret, though important for defense, faced challenges due to limited visibility. Various designs were attempted, but the FN-121 with Village Inn gun-laying radar proved to be more effective in countering night fighters.

Bombs:

The Lancaster's bomb bay could accommodate various weapons, including the 4,000 lb (1,800 kg) "Cookie" high capacity bomb, smaller bombs like the 500 lb (230 kg) General Purpose High Explosive (GP/HE), and anti-submarine depth charges.

For specific missions, modifications were made, such as removing the dorsal turret and guns to carry the 9,250 lb (4,200 kg) "Upkeep" bouncing bomb used in Operation Chastise. Later, Lancaster variants were adapted to carry the 12,000 lb (5,400 kg) "Tallboy" bomb, a scaled-down version of the 22,000 lb (10,000 kg) "Grand Slam" earthquake bomb.

The Lancaster's unobstructed bomb bay and adaptability made it a versatile and effective heavy bomber during World War II.

Operational History of the Avro Lancaster during World War II

The Avro Lancaster played a pivotal role in the Second World War, especially in the European theater. Its operational history is marked by numerous significant missions and contributions to the Allied war effort.

Early Adoption and Missions: In early 1942, the Lancaster was introduced to RAF squadrons, with No. 44 Squadron at RAF Waddington, Lincolnshire, becoming the first to convert to the new aircraft, followed by No. 97 Squadron. The Lancaster's first operational mission involved deploying naval mines near Heligoland Bight on 2 March 1942, as a planned attack on the German battleship Tirpitz was postponed due to poor weather conditions. On 10 March 1942, the Lancaster conducted its first bombing mission, targeting the German city of Essen.

Challenges and Losses: In the early stages, Lancasters faced challenges, and all aircraft were temporarily grounded after a crash in Boston, Lincolnshire, to inspect for any structural issues. The first recorded casualties among Lancaster crews occurred on 24 March 1942 during a mission over Lorient, where R5493 was lost to anti-aircraft fire. Due to high loss rates, daytime bombing missions were limited until the Allies gained aerial supremacy.

Major Operations and Pathfinder Force: In April 1942, Lancaster squadrons carried out a successful bombing raid on the Maschinenfabrik Augsburg-Nürnberg A.G. factory in Southern Germany, receiving praise from Prime Minister Winston Churchill. The Lancaster's role expanded, with RAF Coastal Command using the aircraft for anti-U-boat operations. Large-scale raids were executed against various German cities, contributing to disrupting the German Navy's efforts.

The introduction of the Pathfinder Force (PFF) in August 1942 improved night-time bombing accuracy. These pathfinder squadrons flew ahead of bomber formations, marking targets with Target Indicator flares. The PFF played a crucial role in significant operations, including the successful bombing of Kassel and Henschel aircraft company's factories.

Daylight Raids and Mediterranean Operations: Though designed for night operations, the Lancaster occasionally conducted decoy daylight raids on key manufacturing sites, causing disruptions. Daylight missions against industrial targets in France and Germany were executed successfully, using techniques like flying below German radar cover and maintaining secrecy.

In late 1942, Lancasters began operating in North Africa and supported Operation Bellicose, which aimed to bomb a German radar factory and the Italian naval base at La Spezia. The Lancaster participated in the first 1,000 bomber raid, Operation Millennium, against the German city of Cologne.

Operation Chastise and Berlin Raids: Perhaps the most famous mission performed by the Lancaster was Operation Chastise in May 1943. Carried out by No. 617 Squadron, Lancasters dropped bouncing bombs to breach the dams of the Ruhr Valley. The success of this operation was later depicted in the film "The Dam Busters."

The Lancaster played a crucial role in the Battle of Berlin, conducting numerous raids against the German capital, causing significant damage and disruptions to the enemy. Throughout late 1943, it continued to participate in large-scale bombing missions across Europe.

Pacific Theatre and Legacy: The Lancaster's role expanded to the Pacific theatre, with plans for Tiger Force, the Commonwealth bomber contingent for Operation Downfall. However, the war ended before this operation could be executed, thanks in part to the Lancaster's contributions to the Allied victory in Europe.

In total, the Lancaster conducted around 156,000 sorties and dropped over 608,000 long tons of bombs during the war. It played a critical role in the success of Bomber Command and was praised by both Allied and German officials as one of the most effective bombers of the war. Its operational success and sound design led to the development of various derivatives for both military and civilian purposes, further cementing its legacy in aviation history.

 After World War II

Royal Air Force (RAF): The Avro Lancaster continued to serve with the RAF for several years after the war, during which it participated in several notable operations. In the summer of 1946, No. 35 Squadron Lancasters embarked on a tour of the United States and were autographed by American movie stars. A couple of Lancasters, PD328 and PB873, accomplished several long-distance flights, including round-the-world and trans-polar trips.

While the original Lancaster B.I was gradually replaced, the improved Lancaster B.I (F/E) and B.VII (F/E) models remained in service with RAF Bomber Command. In 1947-1948, No. 82 Squadron received the new PR.1 dedicated photo-reconnaissance variant, painted silver and without defensive turrets, which performed aerial surveys in Central and East Africa.

RAF Coastal Command also operated a small number of grey-painted Lancaster MR.1s based at RAF Kinloss, Moray Firth. However, with the introduction of the Avro Lincoln, a development of the Lancaster, the Lancaster gradually phased out of frontline service. It took until December 1953 for the final Bomber Command Lancaster to be retired. The last Lancaster in active RAF service, a reconnaissance aircraft, is believed to have been retired in late 1954.

French Aéronavale: Avro overhauled 59 Lancaster B.I and B.VII aircraft, which were delivered to the French Aéronavale between 1952 and 1953. These aircraft remained in service until the mid-1960s, being flown by four squadrons stationed in France and New Caledonia for maritime reconnaissance and search-and-rescue roles.

Argentine Air Force: Between 1948 and 1949, 15 former RAF Lancasters were overhauled at Langar for use by the Argentine Air Force. During their service in Argentina, Lancasters were used for offensive purposes, including suppressing and supporting military coups.

Royal Canadian Air Force (RCAF): The RCAF began using Lancaster Mk Xs in 1946. Fourteen of these were modified for aerial and photo-reconnaissance missions and performed extensive mapping of northern Canada until the early 1960s. Throughout the 1950s, the RCAF operated seventy modified Lancasters, designated Lancaster 10MR/MPs, as Maritime Reconnaissance and Patrol aircraft in an anti-submarine role. These aircraft were eventually replaced by the Canadair Argus.

Transport: Immediately after the war, the Lancaster was utilized as a transport aircraft without significant modifications, playing a crucial role in repatriating thousands of prisoners of war (POWs) from various locations across the continent. Repatriation flights continued until November 1945.

The Lancaster was also converted for civil use during the postwar years. Four Lancasters were converted by Avro as freighters for British South American Airways, but they proved to be uneconomical and were withdrawn after a year in service. Additionally, several Lancaster IIIs were converted by Flight Refuelling Limited as tanker and receiver aircraft for in-flight refueling development. Two of these tankers participated in the Berlin Airlift.

From 1943 to 1947, the Canadian Government Trans-Atlantic Air Service (CGTAS) operated a trans-Atlantic military passenger and postal delivery service using a modified version of the Lancaster Mark X. Nine of these aircraft, known as Lancaster XPPs (Lancaster Mk.X Passenger Planes), were equipped with basic passenger facilities. CGTAS pioneered commercial air travel across the North Atlantic, and in 1947, the service became part of Trans-Canada Air Lines, which carried civilian passengers in the Lancaster XPPs until they were replaced by Douglas DC-4s in 1947.