After the First World War, the military expenditure of various countries was greatly reduced, but the Raffair still managed to find resources, and in the 1920s established a force of more than 200 biplanes, and the Chief of Staff of the Air Force, Hugh Rendhard, devoted himself to strategic bombing theory and vigorously developed night bombers.
However, the heavy bombers of that era were not advanced, and only needed to carry two or three 227 kg bombs from England to Paris, far from Berlin.
In August 1927, the British Air Department's code B.19/27 required heavy bombers to be able to carry out night bombing, with a range of 1500 km when carrying 700 kg of bombs.
In 1933, the last British biplane bomber, the HP.50 Hereford bomber, entered service. A year later, the electric turret was invented, which could be loaded with bombers and had the ability to defend itself.
▲ The last British biplane bomber HP.50 "Hereford" bomber entered service in 1933, pay attention to the self-defense machine gun turret under the belly.
The aviation industry was booming in the 1930s, and the British Air Department soon realized that the HP.50 Hereford bomber was lagging behind and had to develop a successor model.
From 1932 to 1934, the Air Ministry issued design requirements for new twin-engine monoplane medium and heavy bombers, which soon received responses from various aircraft design companies.
At that time, the concept of high-speed bombers was in full swing, trying to get rid of enemy fighters through speed, so bombers at that time emphasized speed, bomb load and range, and ignored self-defense weapons.
Since Hitler came to power, however, Europe was on the brink of war, and the British Air Ministry realized that medium bombers could not carry bombs to threaten targets on german soil.
The Royal Air Force needed a heavy bomber with a range of 3200 kilometers, and the more bomb load and speed, of course, the better, so in 1935 the Air Ministry had to re-set new performance standards.
At the end of 1936, the "Hendon" twin-engine bomber of the Fairrie Company entered service, but it was still unable to threaten German targets.
Although the heavy bombers carried excellent bombs and ranges, there was much debate within the RAF. Brigadier General Rainier Weeney, director of technology development for the Royal Air Force, said heavy bombers were too expensive and that multi-purpose medium bombers should be vigorously developed, capable of attacking day and night, and also able to perform reconnaissance, transport and lightning strike missions.
These arguments could not be reconciled, and the RAF decided to reformulate the design requirements for medium and heavy bombers to balance the conflict between range, bomb load, speed and cost.
Brigadier General Werny was also brainstormed to develop a medium bomber that catapulted off so that it could increase the bomb load and replace the heavy bomber, but this idea was not tested.
Another problem was that british aircraft designers, engineers and workers at this time had insufficient experience in designing and building heavy bombers, and the development progress was not fast.
▲ Catapult version of the twin-engine bomber design in the hope of increasing the bomb load and range.
In July 1936, the British Air Department issued the heavy bomber design indicator B.12/36, which requires a range of 3200 km when the bomb load is 6 tons, or 4800 km when the bomb load is 3.6 tons. This design indicator is 3 times better than the performance of existing bombers.
Surprisingly, at least 7 companies should bid, with Vickers and Super Marin favored by the Air Department. However, Schott Brothers claims that they can quickly develop heavy bombers modelled on the S-25 four-engine seaplane, and at an advantageous price.
After a year of waiting, the Ultra Marin design still did not improve, and the Air Department finally awarded the contract for the heavy bomber to the SCHOTT Brothers in October 1937, and their product was the "Stirling" four-engine heavy bomber.
▲ The "Stirling" bomber is the first four-engine bomber of the British Army, due to the small wing area, difficult to maneuver, coupled with the landing gear often broken during take-off and landing, a total of more than 1750 aircraft were produced.
Along with the development of the heavy bomber, the Air Department also wanted to develop a new medium bomber, the P.13/36, which was released in August 1936. The Air Ministry also hypocritically called on countries to vigorously develop medium bombers and secretly develop heavy bombers themselves.
The design indicator P.13/36 requires a range of 4800 km when the new medium bomber carries 1600 kg of bombs, and 2800 km when taking off with a catapult with a 3600 kg bomb.
The main competitors to the medium bomber program were Handley Page, Vickers and Avro. Handley Page developed the HP.55 on the basis of the PH.52 Hampton bomber.
Vickers's work is an improved version of the Wellington bomber, the Warwick bomber, and Avro's product is the most important story to tell today.
▲ Paige's HP.55 bomber.
▲ Vickers's "Warwick" bomber.
Avro's trainer aircraft have long been favored by the Royal Air Force, and chief designer Roy Chadwick has also been working on fighter and bomber design for 25 years, but rarely gets orders.
While other manufacturers focused on developing heavy bombers, Avro decided to do the opposite, betting on medium bombers.
Chadwick's Avro 679 aircraft was favored by the Air Ministry, and the HP.56 of Handley Page was also selected due to the doubling of the RAF budget at the time.
At this time, the tension of the war shrouded Europe, and the British were eager to increase the size of the bomber force, so instead of waiting for the prototype to be built and tested, ordered 200 Avro 679s and 100 HP.56 bombers in July 1937.
During this period, there were proposals to increase the self-defense firepower on the bombers against enemy fighters, and the Minister of The Air Force, Sir Edward Ellington, asked if a 12.7mm machine gun or a 20mm machine gun was needed, but the subordinates thought that the 7.7mm machine gun was enough.
▲ Designer Chadwick.
▲ "Avro 679" prototype, note that it is still a twin-engine bomber at this time.
In order to meet the technical requirements of the P.13/36, Chadwick realized that the Avro 679 needed to have a large 10-meter bomb bay, the aircraft weighed a total of 15.6 tons, and needed to use a more powerful engine.
In 1936, the Rolls-Royce Vulture engine went into production, and its power impressed the Air Department, requiring the prototypes of Handley Page and Avro to be changed to vulture engines. However, there are some technical problems with the Condor engine, and the actual power is not as large as claimed.
Instead of taking the risk of adopting it, Handley Page persuaded the Air Department to combine the hp.55 and HP.56 designs to develop a new four-engine heavy bomber, the HP.57 (later the Halifax bomber), using a Merlin X engine.
Avro also wanted to switch to Merlin engines, but the design and construction of both aircraft was delayed, so the Air Ministry refused, and Avro was forced to continue using Condor engines.
▲ Paige's HP.57 bomber, the "Halifax" bomber.
Avro spent two years building a prototype of the Avro 679, which first flew on July 25, 1939, two months before Paige's four HP.57s.
The test flight results confirmed that the Vulture engine was unreliable, prone to overheating, lower power than expected, and the total weight exceeded one ton, which seriously affected the flight speed.
Designer Chadwick was forced to extend the wingspan of the prototype from 24 meters to 27 meters and modified the design of the tail, but in December 1939, the aircraft crashed due to engine failure.
Although the Air Ministry considered the Avro 679 to be underperforming, by this time World War II had already broken out, so it did not abandon the project and increased the order to 1200 bombers, calling it the "Manchester" bomber.
Designer Chadwick was so dissatisfied with the performance of the Manchester bomber that before the first prototype crashed, he was prepared to design a four-engine bomber on this basis, the Avro 683 or Manchester III, for the sake of safety.
▲ The reliability of the "Manchester" bomber is not good, and the actual combat performance is not good.
Chadwick continued the manchester bomber's fuselage and central wing section, with 70% versatility of parts. The wingspan of the new aircraft was further extended to 33 meters to add two engines.
The Avro 683 project proceeded quickly, and the prototype was completed in May 1940, which was much better than the "Manchester" bomber, and finalized, and a small amount of production was put into production in August.
However, due to the French too far across, the war situation became very passive for Britain and France, and Lord Beaverbrook served as the new head of the aircraft production department to increase production and reduce waste.
Lord Beaverbrook slashed the manchester bomber order to 200 as soon as he came up, and asked Avro to switch to the production of halifax bombers.
Avro was certainly not happy, so in August Chadwick suggested using a Rolls-Royce Merlin X on the Avro 683 to replace the Manchester bomber and guarantee that the prototype would be completed within 6 months.
▲ The "Avro 683" bomber has changed from two-engine to four-engine, and its performance has improved a lot.
Avro moved quickly and completed the fuselage modification work in 4 months. However, the Battle of Britain was underway, and a large number of Merlin X engines were assigned to fighters, so the company worked hard to secretly obtain 4 Merlin X engines.
In November 1940, the improved Avro 683 prototype rolled off the production line, was named the Lancaster bomber, and first flew on January 9, 1941, with the new engine doubling the range and increasing the bomb load by 35%, significantly outperforming the Stirling and Halifax bombers.
Although the design work for the Lancaster was completed, avro had limited production, with only two aircraft per week from October 1941 onwards. By February 1942 it had risen to 10 per week.
On 24 December 1941, the 44th Squadron of british bomber command received the first Lancaster bombers and immediately began rearmament training.
The Lancaster bomber was soon installed in the Royal Air Force, and the ground crew was loading the bomb.
The Lancaster bomber was originally designed as a general-purpose bomber, with no improvements specifically for night bombing, but fortunately the British had gained some experience with night bombing.
The main threat in the night bombing came from the rear and below, but most of the Lancaster's self-defense weapons were facing forward or above, and the firepower was weak, and the German aircraft quickly felt its weakness.
From November 1941 to March 1946, no less than 3425 Lancaster I were produced, with a variant using 4 Merlin X engines with a power of 1460 hp, which was later upgraded to a Merlin 22 or 24 engine.
The Lancaster I has a maximum bomb capacity of 5.4 tons, a maximum speed of 440 km/h, a practical ceiling of 7400 meters and a cruising speed of 380 km/h. The 3 fuel tanks hold 9,792 litres of fuel and range between 2,780 km and 4,000 km, depending on the amount of ammunition loaded.
The defensive weapons were machine gun turrets mounted on the nose, back and tail of the machine, with a total of 10 7.7mm machine guns. The tail turret was the main force against German aircraft, with 4 machine guns that could be turned 160 degrees to the left and right, up and down 90 degrees.
The Lancaster bomber carried out a large number of night bombing missions, and its self-defense firepower was slightly insufficient.
Due to a shortage of Merlin engines, the Lancaster II used Bristol Hercules VI or XVI engines with a power of 1735 hp and only 301 were produced from September 1942 to March 1944. The II is slightly lighter in weight, but the overall performance remains essentially the same.
The Lancaster II had a larger magazine and an additional belly turret to protect it from attacks from below. The Lancaster II was assigned to 4 Canadian squadrons and 2 British bomber squadrons.
The Lancaster III used Merlin 28 or 38 engines and produced 3,039 from November 1942 to June 1945.
The lancaster X engine was replaced by a 1460 hp Merlin 224 engine, and from September 1943 to May 1945, 430 were produced in Canada.
The Lancaster II switched engines and increased abdominal self-defense firepower, but not much.
As the main model of the British night bomber, the Lancaster participated in many bombing operations, and fought fierce offensive and defensive battles with night fighters such as the Luftwaffe Bf-110G. For more night bombing stories, please pay attention to the content of this issue.com.