Did Radar Stop Hitler From Conquering Great Britain?

Did Radar Stop Hitler From Conquering Great Britain?

An incredibly timely invention. 

Key Point: Top-secret radar technology arrived just in time for the RAF to fend off the Luftwaffe in 1940.

Near the end of World War II, Hitler boasted he was about to unleash Vergeltungswaffen, or “vengeance weapons.” These would terrorize and overwhelm Britain and its allies, winning the war for Germany.

The Vergeltungswaffen were the V-1s and V-2s. Indeed, they rained down on Britain and Belgium, causing immense damage, but they were too little and too late for the Third Reich, which succumbed in April 1945.

At the beginning of World War II, under immense secrecy, the British developed another technology that arrived at almost the precise moment and in just barely the proper quantity and quality to save Britain. In saving Britain, it saved the democracies. It was defensive radar and—together with flesh and bone and splendid fighter aircraft—it won the Battle of Britain.

“Never before in our history,” wrote David E. Fisher, “has one invention borne such a distinct and significant role in the outcome of such a pivotal war…. Radar was a device invented not just once, but again and again in many countries at many different times, but in only one of these countries was it implemented at the precise time that would make all the difference.”

Deciphering Germany’s “Enigmas”

Although one might argue that the deciphering of the German “enigma” codes arrived just in time and allowed the Allies to win the war, it was a near thing. Indeed, Fighter Command leader Hugh Dowding was reading decoded “enigma” messages in 1940. These, however, were not nearly so vital to the RAF fighters during the Battle of Britain as the radar warnings. It was radar that tipped the balance. Without it, the British very likely would have lost air superiority in the late summer of 1940, and following that, their island. It is difficult to believe that Nazism would have been defeated if it had controlled Britain from October 1940.

Events proved otherwise, however, and one would not be wrong to lay the honor on radar.

In the early 1930s, much air strategic thinking revolved around the mounting strength of bombers. These were thought to be developing so swiftly and in such numbers that in a future war fleets of them would obliterate industrial complexes, even whole cities. Planners believed that wars might be won merely by air fleets destroying enemy infrastructure and breaking the will of the civilian population. Stanley Baldwin, Britain’s prime minister during portions of the 1920s and 1930s, reflected this thinking when he said in 1932, “The bomber will always get through.” In a sense, this was a mantra for peace: The prospect of mutual destruction by bombers would prevent future wars.

But it also meant that Britain was no longer an island refuge. In minutes enemies could span its surrounding waters and wreak havoc upon its people. Britain’s successful barrier to invasion for a thousand years was suddenly of little consequence. Britain decided to build bombers—in the wan hope that such aircraft would be a deterrent to future war—and to build fighters with which to defend against bombers. But money was scarce and the fighters would be few, especially compared to the numbers of aircraft of the burgeoning menace of Nazi Germany.

If, as some people suspected, Germany would wage an air war against Britain and with superior numbers, then under conditions as military planners understood them, British fighters would eventually dwindle owing to attrition. Tactics called for fighters to patrol sectors, looking for invaders. This required lots of fuel and fatigued the pilots. Moreover, once the pilots descended for more fuel—they could only stay in the air about an hour at full power—they were vulnerable to destruction while landing, taking off, or refueling.

On the other hand, if fighter coordinators knew where the invaders were, pilots could be led directly to where they were needed. Pilots would not have to waste fuel or time in wearisome searches. They would be efficient, far more efficient than if they merely patrolled and fought with whomever they might run across. But how to do it?

With observers on the ground? Not likely. Clouds were pervasive and invaders that were spotted would probably be so close at that point as to pounce on grounded fighters. By engine noise? No, again it did not give enough lead time. The British fighters designed in the middle 1930s and beginning to come off the assembly lines in the later 30s—Hurricanes and Spitfires—needed about two minutes to get into the air (a “scramble”) and about 15 minutes to climb to 20,000 feet. Thus, they would need about 20 to 25 minutes’ lead time if they were to properly position themselves to attack, or just two or three minutes less than the time it took for aircraft rising from northeastern France to reach the English coast.

"Any War Within the Next Ten Years is Bound to be Lost"

They got that lead time, just barely.

In 1934, a man at the Air Ministry named A.P. Rowe, having researched the lack of success of measures to counter the threat of bombers, wrote a memo to his boss, Director of Scientific Research H.E. Wimperis. In it he stated that “unless science can find some way to come to the rescue, any war within the next ten years is bound to be lost.”

Here was one government memo that actually set in motion a chain of events, one with a fortuitous outcome. Wimperis wrote his own boss, Secretary of State of Air Lord Londonderry, and to the Air Member for Research and Development Air Marshal Sir Hugh Dowding, a former World War I fighter pilot, about an idea for setting up a committee to look into the problem. With a stroke of genius, courage, or both, Rowe suggested that the Air Ministry itself might not have the expanse of brainpower to do the job and should therefore bring in outsiders. Both Londonderry and Dowding were unconventional and out of the mainstream. In fact, they were somewhat ignored by the bureaucrats around them, all of which worked to the advantage of the development of British radar. Londonderry and Dowding took Rowe’s and Wimperis’s suggestions and set up the committee, appointing Wimperis and Rowe and turning the chairmanship over to a respected outside scientist and WWI flyer Henry Tizard.

The Tizard Committee, as it was often called (though the official name was the Committee for the Scientific Survey of Air Defense), immediately called upon a brilliant 42-year-old Scot by the name of Robert Watson Watt, then superintendent of Radio Research at the National Physical Laboratory, to look into the scientific merit of radio waves as defense against intruder bombers. In those days, fiction writers were much enamored of “death rays,” invisible rays that could stun or kill. Buck Rodgers-like characters boasted pistol-like “ray guns” that almost silently subdued enemies, and radio genius Guglielmo Marconi was rumored to be developing one for Mussolini. The committee doubted there could be much to make of these fantasies, but asked Watson Watt about the possibility.

Watson Watt did not believe in the feasibility of “death rays” either, but scribbled a message to his subordinate, Arnold “Skip” Wilkins, asking that he calculate the “amount of radio-frequency power which should be radiated to raise the temperature of eight pints of water from 98 degrees to 105 degrees at a distance of 5 km and at a height of 1 km.”

Wilkins was not fooled by the obtuseness of the inquiry. A pilot flying at 3,000 feet has eight pints of blood, nearly pure water, and if the pilot could be made to have a temperature of 105 degrees he would lapse into delirium and lose control of his plane.

Searching for a “Death Ray”

Wilkins replied that the amount of energy needed for such radiation—a “death ray”—was much too enormous to consider, but added that he recalled a 1932 report by British Post Office engineers that their radio waves showed disturbance when airplanes flew nearby—that the airplanes, in fact, re-radiated radio signals—and that this physical property might be a means of detecting aircraft at a distance.

For years scientists had known that metal objects such as ships or airplanes interfered with radio waves. Generally, this was thought to be a nuisance, but some had made the detection connection. In the 1920s, two radio researchers at the Anacostia Naval Air Station in Washington, DC, had noticed radio wave interference when a ship passed and suggested creating a shore-to-shore warning system by placing a transmitter and receiver on opposite sides of a harbor entrance, the better to detect ships entering at night or under foggy conditions. Nothing came of this, though by the 1930s the Americans, the Japanese, and the Germans were all working on radio wave detection systems. The British, perhaps because it was they who suffered the air raids from blimps and bombers in World War I, were more defensive minded than the others and were more determined to research how radio waves could identify the location and bearing of aircraft.