A suicidal bombing raid against the Ploiesti refineries in Romania on August 1, 1943 is illustrative. Out of 164 B-24Ds that took off from Northern Africa without air cover, only 88 returned to their base. Of these only 33 could be restored to fighting condition in the field, whereas the other 55 had to undergo a major overhaul. The objective - to cut off Germany’s gas supply - was not achieved. During the invasion of the Philippines, however, «Liberator» bombing raids were highly successful.
This aircraft was not exactly adored by pilots. It had always been overshadowed by the Fortresses. The reason was very simple - the B-17 had much better chances of survival. There are plenty of cases when B-17s limped back to their base on only two engines and with 30% of their wing area gone, landing without empennage or with the entire front section of the fuselage ripped off. This aircraft was capable of absorbing an astonishing number of direct hits. The B-24 was much less sturdy. A source of pride for aircraft designers, the extended wing proved a curse for flight crews. In addition to high dynamic loads on the control surfaces, such a wing made the aircraft respond very sluggishly to roll inputs, especially at low speeds where ailerons are not very effective. Long wings coupled with short fuselage also made for poor directional stability. All of this, together with the fact that the B-24 was a high-wing design, made landing an extremely risky affair, especially when the aircraft was damaged. Also, in case of an emergency landing on water - which was frequent enough, since the bomber operated primarily over the ocean - the aircraft quickly filled with water - the fault of poorly fitting bomb bay doors - and went to the bottom even before its crew had a chance to deploy life rafts. However, most of the troubles were caused by the extended wing. It was not so sturdily built as that of the B-17 and carried a much heavier load. Very often it broke in two after a few direct hits. All these disadvantages contributed to the extreme unpopularity among pilots of the Liberator. Nonetheless, it was the primary aircraft model in the United States bomber fleet.
Beginning in the middle of 1944, the United States started to curb production of the B-24. Douglas, and North-American all but stopped its production. Ford and Consolidated switched to the more advanced B-24L and B-24M models, which were manufactured in limited numbers: 1667 and 2583 aircraft respectively. The B-24D served as the basis for the development and production of the F-7 long-range reconnaissance airplane, the C-87 airlifter and the C-109 tanker. The Navy received its own B-24D in the form of the PB4Y-1, a special naval version. In March 1944, the industry started to manufacture a special naval Consolidated PB4Y2 Privateer which, unlike the B-24, had only one vertical stabilizer. By October 1945, 739 PB4Y-2s had been turned out.
The failures of the XB-15 and XB-19 failures did not deter the Air Corps from pursuing their concept of a super-long-range bomber capable of striking targets far outside North America. The XBLR specification was revised, and on January 29, 1940, the Air Corps issued to Boeing, Lockheed, Douglas and Consolidated a new order for a super-long-range VLR bomber, capable of carrying a 900-kg bomb load over a distance of 8600 km at a speed of 640-650 km/hr. Preliminary design contracts for the XB-29, XB-30, XB-31 and XB-32 were signed on June 27 and the funds for the construction of the two selected prototypes - XB-29 and XB-32 - provided on August 24, 1940. Douglas's XB-31 and Lockheed's XB-30 were rejected. Boeing's XB-29 was considered the best, and the company received an order for 500 aircraft even before the prototype made its first test flight. As a back up, the military ordered three Consolidated XB-32s.
The XB-32 never seriously competed with Boeing's design; although it lasted for quite a time, the project amounted to nothing more than a series of failures. First, Consolidated was almost half a year behind schedule with its prototype; as a result, the contract for a pre-production series of bombers was cancelled. In the negotiations that followed, the company managed to salvage the project and received a contract for 300 bombers designated “B-32 Terminator.” The very first prototype crashed, killing nearly all those on board. The crash delayed production for another half year. During 1943, two more prototypes were built, but the Evaluation Commission concluded that the aircraft no longer met requirements. Consolidated had to introduce some cardinal changes in its design. The project was saved once more, and the number of orders for the aircraft grew to 1500, but various technical problems persisted, delaying the start of production indefinitely. To ward off bad luck, the company renamed its bomber “Dominator” to no avail. By the end of December 1944, when B-29s had already been fighting for half a year, only five B-32 bombers had been shipped to combat units. Another 40 aircraft, designated “TB-32,” started their service in the Army as trainers since their battle worthiness was under question. It was only on May 29, 1945, that the B-32 flew on its first combat mission. Out of three aircraft taking part, only two were able to take off. Then followed a series of bombing raids on Formosa, the Philippines and Hainan island with a maximum of four bombers taking part. The last combat mission of the Dominator took place on August 28, 1945. Out of four B-32s only two returned to base, although they had encountered absolutely no resistance. In September 1945, production of B-32 finally came to a halt. By that time, 115 B-32s and TB-32s had been manufactured. Out of that number only eight were delivered to the 312th Air Group based on Okinawa. and of that number only four were in fighting condition. The remainder were sold for scrap.
Naval version of B-24 – PB4Y-2 «Privateer».
Hapless, B-32 «Dominator» - one of the six aircraft of this type based on Okinawa.
The prototype of the most powerful WWII bomber «Boeing» XB-29 «Superfortress».
The B-29, on the other hand, was much more fortunate. But for a huge number of design and production flaws, this aircraft would deservedly have been considered the ideal WWII long-range bomber and all the "supers" in its many names totally justified, especially, since B-29 became the first aircraft capable of carrying a nuclear bomb. It was not for nothing that Boeing's project was assigned such a high priority. In April 1941, Boeing started to build the prototype and on September 21, 1942 the first XB-29, powered by Wright R-3350-13 engines rose into the air, to be followed by another three months later. However, on February 18, 1943 there occurred the first of a series of events that would plague the Superfortress through most of its life and subject to question the aptness of the prefix "super" in its name. In one of the test flights of the second prototype, the engine caught fire and the aircraft crashed, killing all 11 on board. This was the first of many serious accidents connected with engine troubles. The 58th Super-Heavy Air Wing started to receive preproduction YB-29s at the beginning of the summer of 1943. On June 1, 1943, a third XB-29 prototype crashed. Until the end of 1943, only 67 pilots received flight training and out of 97 bombers, only 16 were flightworthy. The struggle with this aircraft's capricious engines, which lasted for almost a year, was labeled the “Kansas Battle.”
B-29 flying over Mariana islands.
«Enola Gay» bomber - the symbol of nuclear bombing of Hiroshima and Nagasaki.
Attempts to solve the engine problems were moderately successful. In March 1944, the first B-29 bomber landed at Kwangchowan Airfield in China. The route of B-29s from America to India, across the Atlantic and via Morocco, was over 18,000 km long. Of the 148 aircraft, that reached Marrakech, only 130 made it to India. The others had to return and remain grounded until May 8 because of engine troubles. Once in India, the bombers were unable to take off with full bombload because of short runways, which thus had to be extended by 2200 meters. Despite all these difficulties, on June 5, 1944, the 20th Air Army, made up entirely of Superfortresses, started on a bombing mission to Bangkok. 98 B-29s took off. 14 returned without reaching their target, 5 crash-landed and another 42 made emergency landings at alternate airfields in response to fuel shortages. 18 bombs were dropped on the city and none of them did any damage. During their next operation - a bombing raid on the Yawate steel plant on Kyushu Island on June 14, 1944 - out of 75 B-29s, 18 were unable to take off, one exploded at takeoff, one was shot down by anti-aircraft fire and 6 crashed because of engine fires. 55 crew died in that mission, and the only bomb that was dropped missed its target by 1200 meters. On July 7, out of 100 B-29s that were to bomb Kyushu, only 72 managed to take off, 60 reached the target and 54 returned to base. 7% of the bombs found their target.
At this rate, the Americans could destroy their own bomber fleet without any help from Japanese air defenses. The situation changed somewhat at the end of summer of 1944 with the arrival of the 20th Bomber commander, General Curtis LeMay. He proposed to use napalm firebombs instead of heavy bombs, which produced little damage. In a raid on Anshan on September 26, 1944, the bombers were equally unsuccessful, but losses this time were minimal. In all, by the end of 1944, Americans lost 147 of their latest bombers, or all the bombers they had on hand by the end of spring of 1944. In the fall of 1944, the top military command decided that further bombing raids from Chengtu would be impractical.
Capture of the Mariana Islands enabled establishment of a new air base on Saipan, whence American bombers started to fly in November 1944. However, the Japanese delivered a counterattack on the island, destroying 10 B-29s and damaging several others. The first bombing mission against Japanese home islands was undertaken on November 24, 1944. Out of 111 bombers, 17 returned because of engine troubles while the rest were caught up in a storm and failed to reach their target. On November 27, the Japanese struck again and destroyed 7 more bombers. Up until December, bombing raids by B-29s were not bringing any results. It was only on December 13, that the Americans finally succeeded in seriously damaging the Mitsubishi works in Nagoya. On December 24, the Japanese retaliated against Saipan, destroying 11 B-29s and seriously damaging another 43. The results of B-29 bombing raids from Mariana Islands in the last two months of 1944 were very disappointing. With an average of one bombing mission every four days, losses amounted to 5-6 bombers in each mission.
From January 1945, however, the Americans finally brought the situation under control. On LeMay’s orders, bombing raids were now to take place primarily at night and involve the release from high altitude of small napalm bombs on densely populated residential areas. For the first time ever, the world heard about “carpet bombing” and shuddered in horror. At noon on March 9, 1945, 325 B-29s took off from Guam Air Base. 279 of them reached Tokyo and in the night of March 10 sprayed the city with 1600 tons of napalm bombs, engulfing in flames an area of more than 40 square kilometers. 84,000 civilians died, and more than 1,000,000 lost their homes. In the night of March 13-14, the attack was repeated with 327 bombers taking part. During the spring of 1945, various large industrial centers were attacked and suffered horribly; more then 40% of their total urban area was turned into cinders. Each of these large-scale attacks featured the participation of more than 400 B-29s.
But the most horrible crimes against humanity committed by the Superfortress were the nuclear bombings of Hiroshima and Nagasaki, in which 164,000 civilians died.
Boeing repeatedly tried to solve B-29's engine troubles by using more reliable engines. In 1944, they resorted to the 2100 hp Allison V-3420-11 liquid-cooled engine with the maximum rating of 3000 hp - the same as on the XB-38. The only XB-39 prototype, called the “Spirit of Lincoln” was in flight testing until the end of 1944. It showed improved flight performance but was never put into production. Yet another program of engine modernization started even earlier than that in the middle of 1943. The reengined aircraft, designated “XB-44,” was powered by Pratt & Whitney R-4360-33 Wasp Major engines rated at 3000 hp but never went into production because Pratt & Whitney stopped making the engine when the war ended.
XB-39 «Spirit of Lincoln» powered by in-line «Allison» engines
