On the 6th of June 1944 Operation Overlord, more commonly known as D-Day took place, the largest amphibious invasion in military history.
A week later on the 13th of June, the first vengeance weapon, the German V-1 flying bomb, also known as a buzz bomb or doodlebug landed on the London borough of Bow in Grove Road, destroying a railway bridge and nearby homes, killing six people and injuring thirty others.
This would be the first of almost 10,000 that were fired at England and almost 30,000 that were made, and yet just three weeks later, American engineers at Wright Field, now Wright Patterson Air Force Base, test-fired a copy of the V-1’s Argus As 014 pulse jet engine which was reverse-engineered from crashed V-1 parts brought over to U.S from England.
By early September, the first of a batch of 13 American copies of the V-1 flying bombs had been assembled at Republic Aviation.
With the pulse jet engine being made by Ford and the rest made by Republic, the new weapon will be officially called the Republic-Ford JB-2, the JB standing for jet bomb and unofficially the Loon.
Although it would come too late for the war in Europe, it was thought that it could be used in Operation Downfall, the planned allied invasion of Japan, although in the end it was never used in combat.
But let’s spool back a little bit, and look at how quickly they managed to reverse engineer a copy to be built in America. Well, this wasn’t a coincidence, the Allies had known about the existence of a new German secret weapon since the 22nd of August 1942.
The Germans had been testing an early version of the V-1 launched from Peenemünde which crash-landed on the Danish island of Bornholm, midway between Germany, Poland and Denmark in the Baltic Sea, the cover story was that it was an experiment target drone.
The wreckage was found by the Danish naval officer in charge of the island, which he photographed and sketched and passed on to British intelligence who could see that this was an attempt at creating an unmanned flying bomb.
The information then made its way over to the United States where along with aerial photographs of the Peenemünde base and intelligence reports from on the ground it was decided that the U.S. would create their own jet-powered flying bomb. This would be called the JB-1 nicknamed the “bat bomb” or “thunderbug” and be built by Northrop aircraft.
What’s interesting about this is that it was a very different design to what of the JB-2 which was a V-1 copy. This was a flying wing, very much in the same vein as much larger versions which Northrop was also developing at the same time, but on a much smaller scale.
In fact the prototype JB-1 would carry a pilot to test its flight characteristics, the first test flights would be being towed along a runway.
Northrop had already been contracted to build a small rocket-powered flying wing aircraft, so when they were given a contract to build a jet bomb version they combined the two to create a flying wing bomb, using jet engines instead of rockets.
JB-1A would be the unpiloted version and would use two of the earliest American jet engine’s, the General Electric B-1. The payload would be two 2000 LB bombs fitted inside nacelles in the wing roots.
However, testing didn’t go well as the first JB-1A crashed shortly after the launch. The problem was down to an improper setting of the elevon and failure of one of the B-1 turbojets about 30 seconds before its launch. This issue and the low thrust from the B-1 jet engines as well as other production and structural issues would cause Northrop to look towards a different power plant, and that would be the Ford PJ31 pulsejet that was being used successfully on the JB-2.
Northrop then came up with a new idea, keep the flying wing design but instead use a single pulse jet engine and put the explosives in the wings instead using bombs in nacelles, this would become the JB-10 and it was hoped this would supersede the JB-2
However, this didn’t work out well either with only two successful test flights out of ten and a maximum distance covered of only 26 miles or 42 km. Issues included longitudinal stability, mechanical complexity and the cost of production. The JB-10 cost $55,425 to produce where as JB-2 was $8,620 so in 1946 the JB-10 was terminated.
Another jet bomb project which used the Ford PJ31 pulsejet was the JB-4, a powered variation of the GB-4 glide bomb. This used a television camera and radio command guidance system instead of radar guidance of the JB-2, so it could be flown by remote operator and more accurately targeted, something which had been developed earlier on in the war to create remotely controlled aircraft and the first drones.
However, although it had the ability to cruise over 400 miles an hour 640 km/h it was plagued by reliability issues and a smaller 750lb or 340kg load compared to the 2000 LB or 910 kilogramme bomb of the GB-4.
Also due to the limited technology at the time, it was difficult to make out anything on the TV monitor except on a completely clear day and with the end of the war in 1945 the project was ended without the JB-4s being put into operational service.
The JB-2 however was doing well with an improved guidance method being developed using a radio–radar control system. The missile would have an AN/APW-1 radar transceiver and be tracked by the SCR 584 radar unit. Radio signals would then be sent to correct its course making it a much more advanced missile than the original German V-1.
An initial order of 1000 units was made with subsequent production of 1000 units per month was anticipated.
It was a thought at one time there could be as many as 75,000 JB-2s put into production, the problem with that was that it alone would have taken up almost 1/4 of all the shipping available between America and Europe.
But by the time is was ready the war in Europe was over there was little point in having it deployed there and attention turned to the war in the Pacific and the planned invasion of the Japan.
This would include a 180 day massive bombardment of the Japanese home islands and it was thought that the JB-2 would be used on mass as part of this bombardment being launched from Navy ships, escort carriers and aircraft, as well as from land as it was captured from the Japanese.
However, after the dropping of the atomic bomb and the rapid capitulation of the Japanese government, Operation Downfall was cancelled and the production of JB-2’s was terminated in September 1945 with 1,391 manufactured.
But this was only the beginning of America’s guided missile story.
Over the following ten years or so, much work and testing was done with JB-2 including upgraded radar control, the ability to control it from submarine or ship and its use as a target drone for surface to air and air to air missiles which would lead to the Martin MGM-1 Matador, the first operational surface to surface cruise missile built by the United States from 1952 to 1962.
This would be followed shortly afterwards by the second generation SSM-N-8 Regulus, a ship and submarine-launched nuclear-capable turbojet-powered cruise missile.
Although the Regulus had major operational drawbacks, which included having a submarine crew to assemble the missile in whatever weather was occurring, a limited range of 260 miles or 417km and as it was slow and activity-guided by the ship that launched it, if the ship was destroyed then the missile would be disabled and it could be intercepted on its journey.
But it did provide the first nuclear deterrence for the US navy and played apart in the Cuban Missile crisis before the Polaris, Poseidon and Trident nuclear missiles and was the forerunner to the Tomahawk cruise missiles that are still in use today, and all from the V-1 copy, the JB-2.
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