Most people have heard of the incredibly accurate Norden bombsight (see video tour of the Norden bombsight) that was credited for revolutionizing accuracy of heavy bombers like B-17s, B-24s, and B-29s. It was an electromechanical device that took bombardier inputs of altitude, airspeed, heading, and wind speed and direction, then calculated the impact point of the bomb. An accuracy of 75 feet was claimed under ideal conditions - provided by a mechanical computing device. By 1956 when this article was published (eleven years after WWII and three years after Korea), the Norden had been replaced by radar-integrated bombing systems. Additionally, ground-based radar measurement systems were in use to train aircrews without the need to drop physical bombs. Instead, virtual bombs were launched and computers in a Radar Bomb Scoring (RBS) unit determined where a real bomb would have hit.
Radar Scores SAC Bombing Test
At "Bombs away!" signal, radar pulse sent from plane is received at Radar Bomb Scoring (RBS) station. Computers then graph hit or miss. Left, Col. Harold A. Strack, RBS Group Commander, watches sky from atop van housing Mobile Radar Control System (MSQ). Pulses received by antenna at his left are translated into data and plotted by technicians shown below at work inside RBS control station.
Airmen cried "Bombs away!" but instead of devastating blasts the only visible evidence of the crew's ability to destroy a target was cryptic electronic signals observed by technicians at work inside a special radar station.
This was the general picture during a recent bombing and navigation competition between the huge bombing planes of the Strategic Air Command (SAC). Some of the nation's top bombardiers and crews were rated with unfailing accuracy, yet they never released one real bomb. It was all done by radar and computers, linked together to form an ingenious tracking and scoring system that has also been used as a valuable training aid for fledgling airmen.
Here's what happens: when the airplane signals "Bombs away!" a radar pulse is sent from the bomber to the ground station, known as a Radar Bomb Scoring (RBS) unit. The station is built inside a mobile van. A Mobile Radar Control System (MSQ) in the van uses the received pulses to track the course of the bomber, while computers determine the accuracy of "hits." Blips across a radarscope represent the flight path of the plane. The results of the scoring computer are shown as a thin red line traced by an electronic "pen" on a sheet of blank paper. With this data, the RBS group working in the van knows just where the "bomb" hits.
Variable factors such as wind drift are taken into account by the computers. Pinpoint accuracy enables the RBS personnel to judge the amount of error in the bombardier's salvo. Similarly, the scores can estimate the amount of damage that would ensue with a hit.
As a training aid, the RBS system provides crews with a sense of realism previously missing from mock bombing runs. The MSQ radar and computing equipment was manufactured for SAC by the Reeves Instrument Corp., a subsidiary of Dynamics Corp. of America, 25 West 43 St., New. York 36, N. Y.
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