Bombardier

The reason for the 15 hour round trip to the Empire was for the bombardier, in a span of around 3 minutes, to aim at a target and drop up to five tons of explosives and incendiaries on the enemy. Not that his job took only three minutes. The bomb run was actually longer but the critical part took anywhere from 90 seconds to three minutes. Like the rest of the crew he had attended a general briefing some 10 hours earlier, then a special briefing for his position, followed by target study. On the flight line he preflighted his equipment and inspected the loaded bomb bays. Discussions were held with the navigator and radar observer on their interrelated duties.

On becoming airborne and before cabin pressurization, he entered the bomb bays to remove the fuse safety pins to arm the bombs. Bombs were loaded safe and would not detonate unless the safety pins were removed. The pins were put in a special pocket in his flying suit and delivered to the interrogation officer at the end of the mission. His trip through the bomb bays was on a narrow catwalk about 18 inches wide.

Under visual conditions the bombardier was in complete charge of the bomb run. Approaches to the target were usually over water and the radar observer would direct the IP turn to the bomb run heading and yield to the bombardier. The Norden Bombsight was engaged to the autopilot and the bombardier steered the plane to target. Flight data had been fed into the brain of the Norden. The pilot was responsible for maintaining constant airspeed and altitude. The bombardier concentrated on killing course and rate.

He did this through the eyepiece by placing a vertical and a horizontal crosshair on the target. With the information in the bombsight the crosshairs should remain stationary on the target as the sighting angle to target continuously changed. To achieve this the bombardier had to make adjustments with the rate and course knobs. The dial on the rate knob moved as the sighting angle continuously changed.

The split second timing of the bomb release was determined by the bombsight and bombs were released automatically. In formation, the following aircraft would toggle their bombs as the leader released his. The deputy lead would use the bombsight and carry on as if he were the leader. He was the backup in case the leader developed a problem or was disabled by flak or fighters. On the entire bomb run no evasive action was permitted making the bombers especially vulnerable to enemy action. All the information in the bombsight was useless unless altitude, airspeed and course remained constant.

Bombing with Radar

If cloud conditions prevented a run on the primary target, the flight leader would direct and lead his formation to a preselected alternate target. This was the case where the target was inland. APQ/13 Radar had its limitations in hitting this type of target. When the primary target was along the coast, rivers or lakes a successful radar run was possible and only the method was changed, not the target.

In Europe only pinpoint military and industrial targets were targeted by US units. Any damage to civilian population was collateral and was caused by error and not by intent. All raids were conducted in daylight and bombs would only be released with the Norden Bombsight and positive identification. The flak and fighter opposition made it very costly in men and equipment to achieve any measure of success. It also required perfect, cloudless weather. The alternative was the bombing of a secondary target or a target of opportunity.

Meanwhile the RAF was engaged in night area bombing of industrial complexes. Given the experience of London during the blitz, it is understandable that the British would have less reservation to use this method. This was not revenge or justification, but a realization of the totality of war. In the area of the factory were all the support services, utilities, transportation, sub-contractors, and workers. In older cities it was impossible to isolate the civilian living areas from the strategically important targets. C’est le guerre. The RAF found their targets and released bombs using the Gee System. It worked on the same principle as radar, the reception of a radio pulse and timing the interval between transmission and reception. It could provide an exact position and a precise moment to release bombs. The radio pulse was transmitted from three antennas along the English coast and had a maximum range of 400 miles depending on the altitude of the aircraft since it was a line of sight operation. Only pathfinders carried this equipment, dropping parachute flares over the target areas. The following force would use the flares and fires started by them as targets.

The system was a success in Europe but was not usable in the Pacific. The targets were 1500 miles from base. The nearest friendly land mass was Iwo Jima, still 750 miles distant and well out of range and line of sight. The solution was the equipping of each B29 with the APQ13 Radar and later in the campaign with the advanced APQ7. These systems were both transmitter and receiver. No land-based transmitter was needed. It evolved from navigation and back up bombing instrument to the primary tool to destroy the war production capability of Japan.

From the start of B29 operations from China bases in June 1944 and from the Marianas in October 1944, Air Force Chief, General Hap Arnold, 20th Bomber Command General Saunders, and 21st Bomber Command General Hansell, strictly followed Air Corps policy of precision bombing of military and industrial targets only, from altitudes of over 30,000 feet and minimum exposure to civilians. Results were far from satisfactory up to the time of General LeMay’s arrival in the Marianas in January 1945 to take command of the 21st. He too strictly observed the same policy. During the winter months operations were hampered by winds as high as 200 mph in the target area and a multitude of operational problems arising from the mechanical strain of operating at very high altitude. It became obvious that the disappointing performance of the B29 had to be reversed and a bold new plan was necessary.

Strategists examined anew the makeup of Japanese war production. There were no definitive boundaries between factory facilities and residential areas. Abutting the large plants were all the support industries, office complexes, retail establishments, and residences, homogenized into a strategic mass. This was the package slated for destruction. Not an entire city was targeted, only that part that was strategically important. It would be accomplished by low-level night attacks with Radar and the Radar Operator becoming the eyes of the Bombardier and the Norden Bombsight. The agent was Napalm that would reduce large areas of enemy cities to ashes. Radar was upgraded from a backup system to a specialized primary application.

The plan went into effect with the March 9, 1945 raid on Tokyo. At the briefing for the mission the crews received the details with misgivings and skepticism. A reduced fuel load, an increased bomb load, and “on the deck” altitude between 5,000 and 9,000 feet, added up to a recipe for disaster. The raid however was an unqualified success and the method became standard for the remainder of the war, though altitude was increased in later raids to allow for the offset bombing of more inland targets.

Daylight precision bombing was not abandoned but was vastly improved at the same time. The 20th came down from the stratosphere. After March 9th the average bombing altitude was around 20,000 feet. The results were dramatic. On April 12th the 39th Bomb Group made its combat debut as part of a strike force of 130 planes attacking the two chemical plants at Koriyama, 125 miles north of Tokyo, in daylight under a cloudless sky. Seventy percent of each complex was destroyed and Japan’s tetraethyl lead production was reduced by 50%. On May 10th the 314th Wing, led by the 39th, destroyed 45% of the storage and refining capacity at Otake on the Inland Sea. These two raids did much to keep the major part of the Japanese Air Force on the ground for the remainder of the war.

The purpose of this narrative is to portray the way Radar worked. To do this the May 25th raid on Tokyo is reconstructed from memory and assumptions. Our crew was a pathfinder and was one of two assigned to a target area to make an “X”, a visual aiming point for the remainder of our group to use. On most missions however each crew made its own run by radar. It was just as effective. Odds were that a very high percentage would make very accurate drops. The aiming point had to be approached and identified with radar and within a short time the “X” would be obliterated by smoke and spreading flames, becoming useless as an aiming point. One option was to aim visually at the perimeters of the fires to broaden the effects of the fire.