While all this was going on, that frustrating problem of how to defend against enemy aircraft continued to be a sore thumb on the mailed fist of all armed services. Some argued that the best and only defense was yet another aircraft, but others looked for ways to improve the existing ‘low-tech’ defense approach being used—the venerable anti-aircraft gun. A man named Merle Anthony Tuve was another of those brainy PhDs tinkering at the edge of technologies that would soon combine to become lethal weapons of war.
He was exploring the use of radio waves to measure the height of the atmosphere, and it soon became apparent that radio waves could be used to measure other things as well. The fledgling technology that came to be known as ‘Radar’ would be one thing that emerged from that observation. One day, considering the problem of those bothersome aircraft, Tuve theorized that AA guns might be made much more effective if their shells could ‘see’ enemy planes. The way to give them those eyes would lie in his tinkering with radio waves, but his colleagues thought it would be too difficult to try and mount delicate radar technology on something subject to violent forces like an AA gun shell.
“No,” said Tuve. “Just use the radar as an early warning system on the ground, or something to help the gun get pointed in the right direction. What I’m talking about is just something that can tell the shell its target is near. You know, those shells have quite a blast radius for fragmentation shrapnel when they explode, but right now, they only do so on contact. Most AA shells just fly right past a target unless they score a direct hit, or explode at the fixed altitude set by their fuse. What I’m talking about is a kind of proximity fuse that can set off that shell when it gets anywhere near an enemy plane.”
Tuve became the founding director of the Applied Physics Laboratory, now at John Hopkins University, and there he set about to develop his idea, much to the delight of the Army. It took as many as 25,000 rounds fired from an AA gun for each hit obtained when Tuve started his project. During the Battle of Britain, the British estimated they fired an average of 18,500 rounds at German aircraft for each one they actually destroyed. When Tuve finished, he had cut that down to between 30 and 60 rounds, and this would improve as the war progressed. That was a staggering leap forward in the precision and effectiveness of AA guns, and it would become one of the most closely guarded technologies of the US war effort, as secret as the Manhattan Project, and in many ways more significant in its impact on the war effort in general.
Both the British and Germans had looked at the idea in 1940, but deemed it impossible to achieve. Tuve proved them wrong. What the team created was a miniature radio device that could simply bounce radio waves off any target it was approaching. Well before the development of the transistor, radios of that day all relied on very fragile vacuum tubes. How in the world would the team fit a glass tube into an artillery shell, and have it survive the violence of being fired from a gun?
The answer would come from another man, Dr. James Van Allen at the University of Iowa. He met Merle Tuve at the Carnegie Institute, and became a member of the National Defense Research Committee, the same group that would spawn the Manhattan Project. Van Allen had been working on creating more durable vacuum tubes for special rugged duty. He had learned that a small company was also involved with miniaturizing the tubes so they could fit inside a hearing aid. Those two attributes, ruggedness and miniaturization, would become key factors in the successful design of Tuve’s radio proximity fuse.
Materials were found to shield and cushion the glass, prevent the fragile tungsten elements inside the tubes from being damaged, and allow the vacuum tube to survive the shock of being fired from a gun—20,000 G-forces. Van Allen’s solutions helped the team deliver its first shock-proof tube by January of 1942 in Fedorov’s history. But the question of how to advance this technology had come earlier in these Altered States, another odd effect of Kirov’s influence on events. It was June of 1941 when the first fuses were tested here, and six months later, as many as 5000 proximity fuses had been produced and installed in AA gun rounds. That was largely due to Tuve’s tremendous organizational ability, and the team he coordinated to solve the problem. He believed in Napoleon’s first principle of war: “I can make up for lost ground, but never lost time.”
So Tuve insisted his personnel forget about saving money or resources, and focused entirely on saving time. It didn’t have to be perfect, it just had to get done, and before the enemy developed the same thing. “The best job in the world is a total failure if it is too late,” he said, “We don’t need the best possible unit, but we damn well want the first one.” Tuve insisted on speed in every aspect of the development process, but still achieved a 97% quality control rate on the overall system. Everything needed, the radio transmitter, antenna, tubes, battery detonation switches and safety measures, all had to fit into a tube no more than 1.5 inches wide and 8 inches long, and with a shelf life for storage in the shells of up to three years or more.
It would later be learned that the Germans had employed at least 50 small project groups to try and solve the same problem, but believed it would not be achieved in time to matter in the war. Tuve proved them all wrong. His small initial team would soon burgeon into massive production centers producing 40,000 rounds per day. Over 22 million would be produced in the war before it ended.
Naturally, the Navy was very interested in the idea of a much more accurate AA gun to protect its ships. The gun that would fire them was the QF 5-inch dual purpose gun mounted on ships from destroyer class up to battleships and carriers. The technology increased AA accuracy by an order of magnitude, one day achieving 90% kill rates on V-1 Buzz Bombs with only ten rounds fired. It was going to be so significant, that it would spell the doom of Japanese naval and land based air power as an effective strike weapon of war. The Japanese would eventually learn the trick themselves, but too late in the war to really matter.
They did not know it at the time, but the fruits of Tuve’s project, the effort of over 80,000 men and women, had already produced proximity fuse rounds for the U.S. Navy to make surface ships much harder targets for naval strike craft. The first ships to be fully equipped with the new rounds were already at sea, and had already fired them at the planes and pilots of Hara’s Carrier Division 5.
During that battle, Halsey had ordered Fletcher’s battleship squadron to make a run at the Japanese positions around Nandi, particularly the airfield they had captured there. Two ships in that squadron had the new special proximity fused AA shells for their 5-inch guns, the USS South Dakota, and the light AA cruiser Atlanta. They would now report back that the new rounds were a tremendous success. South Dakota had taken down four enemy planes for the expense of only 42 of the new rounds. Without them they might have had to fire close to 500.
The new proximity fused shells had arrived six months earlier than they did in the unaltered history, when the cruiser Helena was the first to receive them in November of 1942. The use of the shell itself, and even its existence, was still to be considered a closely guarded secret. They could only be fired in situations where the military believed it would be impossible for the enemy to ever recover a dud or misfired shell to learn its secret. This was why all those 5-inch guns now carried two types of rounds, one for use against other naval targets or in shore bombardment, and the proximity fused rounds for use against enemy aircraft.