Chapter 477 Belfast (4)

During World War II, bombers had only a few ways to drop bombs.

In the famous dive bombing, the plane dives down at a steep angle, and the angle with the ground is generally more than 45 degrees, or even close to vertical. Drop bombs when diving very close to the target, and pull up quickly at the same time.

However, dive bombing has very high requirements on aircraft performance. Because the aircraft is subjected to great force during the dive, the fuselage structure must be strengthened, the aerodynamic design is also different, and a dive speed brake is required, which leads to a decrease in aircraft speed and performance. In addition, once the bomber starts diving, it cannot change its course, and it is easy to be bitten and shot down by enemy fighters at this time.

There is also a kind of gliding bombing. This bombing method is usually used by fighter-bombers, attack aircraft, or fighters for temporary ground bombing. The aircraft enters along a small gliding angle, changes to level flight to drop bombs when approaching the target, and then pulls up quickly. The Soviet "Il-2" attack aircraft often bombs the ground in this way.

This bombing method is not accurate, and the kinetic energy of the bomb is not large, but it does not require high aircraft strength, saves fuel, and is suitable for bombing surface targets.

There is also the most common horizontal bombing.

Because the bomber's flight altitude is usually high, the bomb does not fall straight up from the plane, but a parabola. Therefore, the bombing advance angle must be calculated to allow the bomb to hit the target accurately. This also involves many parameters such as aircraft airspeed, ground speed, drift angle, wind speed, flight altitude, average bomb drop speed, etc.

There is no reliable means to drop the bomb accurately.

However, the US military seems to be unconvinced. Their strategic bombing idea is to emphasize high-precision strategic bombing, that is, to carry out precise bombing on a specific industry or target of the enemy country to achieve the purpose of weakening the enemy's war strength. For example, in the strategic bombing of Germany in World War II, the US military focused on the destruction of Germany's fuel industry and manufacturing industry, and the effect was immediate.

Of course, in terms of technical requirements, high-precision bombing requires high-range and load-bearing bombers, and the US military also needs a very important thing-bomber sights. Advanced sights can ensure that bombers can carry out high-precision bombing at a height that is maximally free from the influence of enemy anti-aircraft guns, which can not only avoid losses but also ensure accurate bombing of targets.

In response to this, the United States spent 1.5 billion US dollars to develop a bomber sight - the Norton sight! This was a huge expense at the time. The total investment in the Manhattan Project that year was about 3 billion US dollars, which means that the Manhattan Project could only develop two projects similar to the Norton sight. This shows the importance the US military attaches to this equipment!

This Norton bomber sight developed by the American Norton Company is roughly divided into two parts, namely the stabilizer and the sight.

The stabilizer is a working platform that uses an anti-gyro to maintain horizontality, and its function is to provide a stable working platform for the sight. The stabilizer and the bomber's autopilot work together, so that the sight must be calibrated with the stabilizer, which can ensure that the direction aimed by the sight is consistent with the direction of the aircraft's flight.

The most important sight part is the main working system of the entire Norton bombing sight. It consists of three parts: a mechanical analog computer for calculating the impact point, a small telescope, and a system consisting of a motor and a gyroscope.

The use of the Norton bombing sight is not very complicated. When the aircraft approaches the target area, the bombing aimer needs to use a telescopic eyepiece to find the target, which can be completed with the help of a set of reflectors. After finding the target, the bombsight operator can place the target in the center of the field of view and then turn on the power switch of the Norton bombsight. Once the switch is turned on, the telescopic eyepiece servo will ensure that the eyepiece is always aimed at the selected target. Since the angular velocity of the telescopic eyepiece rotation of the service agency depends on the distance of the target and the closing speed of the aircraft, this requires the bombardier to set the aircraft's airspeed and altitude data on the Norton bombsight according to the display data on the aircraft instrument.

After the Norton bombsight is set, the bombardier will let the "Norton" take over the aircraft. From this point on, it is no longer the pilot who actually controls the aircraft, but the "Norton". It will control the aircraft to fly along the bombing route calculated by the simulation computer and correct the aircraft in time according to the last adjustment made by the bombardier. When reaching the pre-calculated bombing point, the "Norton" will automatically drop the bomb, so that the hit effect of the bombing will be significantly improved. When using the "Norton", the bombardier can theoretically drop the bomb from an altitude of about 7,000 meters to a distance and a circle with a marked radius of 30 meters.

Of course, this is just theory, it is impossible to do it in actual combat.

Norton's theoretical calculation at the time assumed that the aircraft dropped bombs at low altitude and low speed, but bombers such as B17 carried out bombing at high altitude, and the Norton sight performed poorly at this time. Moreover, the bombardier must visually see the target, and cloudless weather is not always available, which also limits the ability of the Norton sight.

There is a famous example. In 1944, the Allies bombed the chemical plant in Leuna, which covered an area of ​​757 hectares. In 22 rounds of bombing missions, the aircraft were equipped with Norton sights and dropped 85,000 bombs. However, only 10% of the bombs fell into the 757-hectare chemical plant, and 16% of these 10% of bombs were duds. After suffering several fierce attacks, the factory started working again within a few weeks.

But even so, the technicality of "Norton" was outstanding at the time, so the US military regarded the "Norton" bombing sight as top secret and formulated a series of confidentiality regulations, such as the "Norton" sight must be covered with canvas, can only be installed on the bomber before takeoff, must be removed immediately after landing, and the disassembly process must be carried out under the supervision of armed guards, the crew of the bomber must swear to protect the secrets of the sight with their lives, and destroy the "Norton" sight before the plane is forced to land and captured, etc.

The funny thing is that under such strict security measures, Germany got the complete design drawings. Because Norton had a group of German engineers, one of whom was Hermann Long, who handed over the entire set of drawings to the German side.

Although Germany also has a Norton sight, it is not so easy to use like the American one. In addition, the German Air Force did not have a large number of strategic bombers in World War II... so it is even more useless.

Today, Germany has successfully developed a navigation/bombing radar with a wavelength of 3 cm. With this bombing radar, bombers can achieve the same bombing accuracy at night or in thick clouds as in clear daytime. The darkness and clouds can also protect bombers from interception by enemy fighters and anti-aircraft fire.