Jet stream winds played havoc with bombs dropped from 30,000 feet over Japan.
On March 9th 1945 the United States Army Air Corps (USAAC) Twentieth Air Force initiated Operation Meetinghouse. The Twentieth had been using their B-29 Superfortresses to bomb Japan from bases in the Marianas since November 24th 1944, and from bases in China since April of 1944. Results of their missions were unsatisfactory. A change was necessary. It was time for General Curtis LeMay.
America’s very first raid of the war on Tokyo took place on April 18th 1942, when USAAC Lieutenant Colonel Jimmy Doolittle led sixteen twin-engine B-25B Mitchell bombers, launched from the deck of the aircraft carrier USS Hornet (CV-8), to attack Japanese targets including Tokyo and Yokohama. The bombers were to continue flying west after their attacks and land in China. Because the ships in the task force had stumbled upon Japanese picket boats, the bombers were forced to launch much earlier, and at much longer range from Japan, than planned.
While the raid did little real damage it provided a much-needed morale boost for an America reeling after Pearl Harbor and the subsequent Japanese sweep through much of the Pacific. The fate of the bombers was sealed when they took off so far from their planned departure point. None of the bombers reached the planned recovery airfields in China. However, Japan was forced to commit resources to the defense of the home islands, which had been thought to be safe from American attack, for the remainder of the war.
Fast forward to 1945. Results of the high altitude precision daylight bombing of Japan by the Twentieth Air Force over the previous 11 months were unsatisfactory due in large part to very strong high altitude winds aloft over Japan. These winds, later to be recognized as the jet stream, made the approach to the target areas, the bomb runs, and egress from the target areas after bomb release over Japan problematic. In some cases B-29 groundspeeds were reduced to less than 100 miles per hour when bucking the strong headwinds. When bombing from high altitude, bombing accuracy was significantly reduced by the high winds affecting free-fall bomb trajectories. The consistently cloudy weather over the Japanese islands also contributed to the overall lack of precision in high altitude precision daylight bombing.
General Curtis LeMay, the new commander of the Twentieth Air Force, took one look at the results of the bombing of Japan from China since April, and especially from the new bases on Saipan, Tinian, and Guam since November, and decided to change the tactics employed by the Twentieth. There would be no more high altitude precision daylight bombing of Japan. LeMay’s crews would bomb from low to mid-level, and they would bomb at night.
The B-29 aircrews tasked with flying the missions harbored misgivings about the changes LeMay instituted. Attacking between 5,000 feet and 9,000 feet seemed suicidal, and removing all the defensive guns from their bombers except the tail guns made little or no sense to the crews.
But there was method to LeMay’s madness. The Japanese anti-aircraft batteries had been proven to be least effective between these altitudes, and even less so at night. Removing the guns, which were not likely to be needed at night, was going to lighten the loads on the aircraft. Removing the guns also meant removing the gunners required to operate them from the bombers during the missions.
During the first carrier-based raids on Japan since the Doolittle Raid, the Navy’s Task Force 58 had run roughshod over the Tokyo area in February of 1945 attempting to eliminate as many Japanese aircraft and as much of their support infrastructure as possible in preparation for the invasion of Iwo Jima. These raids also had the beneficial side effect of having neutralized a large number of fighters that could be used against LeMay’s bombers.
When as many of the B-29s based in the Marianas had been repaired and prepared as possible the mission was a go. Led by pathfinder B-29s responsible for group navigation and initial targeting, a total of 327 B-29s took off from the sprawling bases in the Marianas on March 9th 1945. Knowing their target was Tokyo, many of the bombers also carried crew members who, despite LeMay’s orders, had reinstalled the .50 caliber machine guns in their B-29s and went on the mission.
The majority of the bombers carried cluster bombs which were set to release their napalm-filled bomblets between 2,000 and 2,500 feet above ground. The bomblets were designed to punch through the light construction of the structures and spread napalm inside them. Other bombers carried white phosphorous bombs. These ordnance selections were carefully considered. Sample Japanese “cities” were built State-side at test sites using representative building materials. A variety of munitions were tested against them. The napalm cluster bombs and the white phosphorous bombs were most effective against the sample Japanese buildings.
In all the 299 bombers attacking Tokyo dropped 1,666 tons of bombs on target. 22 of the bombers failed to return from the raid, several of which were overstressed when flying through the turbulent air caused by the fires over the burning city and broke up in mid-air.
The damage done to Tokyo that night was staggering. 25% of the city was destroyed, an area of approximately 16 square miles. It is impossible to determine the exact number of dead and wounded because figures cannot be accurately deduced. Suffice it to say that at least 100,000 were killed and likely thrice that number wounded and / or burned with over one million left homeless. Operation Meetinghouse was single most destructive bombing raid ever, and only gusty prevailing surface winds prevented a Dresden-like firestorm.
The Twentieth Air Force continued to use the weapons and tactics first employed on the night of March 9th 1945 for the remainder of the war against Japan. Subsequent raids were not as destructive, but nearly eliminated the ability of the Japanese to manufacture weapons and most other war materials. By June, the B-29s began dropping leaflets over cities to be attacked three days prior to the attack warning the civilian population that an attack was imminent.