Operation Matterhorn was a military operation of the United States Army Air Forces in World War II involving the strategic bombing of industrial facilities in Japan, China and Southeast Asia by Boeing B-29 Superfortress bombers. The creation and maintenance of bases for the B-29s in India, Ceylon and China was a logistical undertaking of enormous magnitude and difficulty.
The B-29s were based in India but staged through bases around Chengdu in China's Sichuan province. Operations were conducted from China because no other sites within range of Japan were in Allied hands in early 1944. Since the Japanese had cut the Burma Road in 1942, the only line of communications with China was over "the Hump", as the air ferry route to China was called. All the fuel, ammunition and supplies used by American forces in China had to be flown in over the Himalayas.
The B-29s required airbases with runways that were longer and stronger than those of smaller bombers. Five airfields in Bengal in India were upgraded to take them.Supplying fuel by rail would have placed too much strain on the railways, so a fuel pipeline to the airfields was laid from the port of Calcutta. The four B-29 airbases around Chengdu, along with five airstrips for fighters to defend them, were built by tens of thousands of Chinese laborers with hand tools. In November 1944, American bombers began raiding Japan from the Mariana Islands, and the B-29s left the logistically difficult and increasingly vulnerable bases in China in January 1945.
Background
The Boeing B-29 Superfortress was one of the largest aircraft of World War II. It was also the most expensive military project: the $3 billion cost of design and production (equivalent to $ billion in ), far exceeded the $1.9 billion cost of the Manhattan Project. It sported state-of-the-art technology, including a pressurized cabin and an analog electromechanical computer-controlled fire-control system, and was powered by four Wright R-3350 Duplex-Cyclone radial engines. The large number of advanced features resulted in more than the usual number of problems and defects associated with a new aircraft. This was compounded by efforts to fast track its introduction into service. The Wright R-3350 Duplex-Cyclone engines in particular gave a lot of trouble, and were prone to catching on fire.
In April 1943, the commander of the United States Army Air Forces (USAAF), General Henry H. Arnold, set up a special B-29 project under Brigadier General Kenneth B. Wolfe. Colonel Leonard F. Harman became his deputy. For his assistant chief of staff for operations (A-3), Wolfe secured Brigadier General LaVerne G. Saunders, who had been awarded the Navy Cross in the Guadalcanal campaign.
To control the B-29s, the 58th Bombardment Wing was activated on 1 June. A senior formation, the XX Bomber Command was activated in Salina, Kansas, on 27 November 1943, with Wolfe as its commander, and Harman became the commander of the 58th Bombardment Wing. To avoid the B-29s being misused on the battlefields instead of against the Japanese home islands, the Joint Chiefs of Staff approved the establishment of the Twentieth Air Force on 4 April 1944 under Arnold's command. The XX Bomber Command became part of the Twentieth Air Force. The role of the theater commanders was restricted to providing logistical support and the defense of the B-29's bases.
The high cost of the B-29 program put Arnold under pressure to produce results. He wanted the B-29s used to attack strategic industrial targets in Japan. The basing of the Superfortresses in China was raised at the January 1943 Casablanca Conference. No other locations within range of Japan were in Allied hands or expected to be so in 1944. Moreover, because the war against Germany had priority, it was considered essential to keep China in the war against Japan until Germany was defeated and the Allies could redeploy forces to the Pacific. This had political implications, and the President of the United States, Franklin D. Roosevelt, was a staunch supporter of aid to China. The basing of the B-29s in China therefore received his endorsement.
Logistical support for operations in India and China was through the port of Calcutta, which was estimated to be able to handle the additional per month. After the Japanese cut the Burma Road in March 1942, the only line of communications with China was over "the Hump", as the air ferry route over the Himalayas was called. Until the Burma Road could be reopened by the ground forces, it was the only source of fuel, ammunition and supplies for the China-based American Fourteenth Air Force and Lend-Lease aid to the Chinese ground forces. This involved flying over the world's tallest mountain range in treacherous weather conditions and with the possibility of interception by Japanese fighters.
The Matterhorn plan called for supplies to be flown from India to China in Consolidated B-24 Liberator bombers converted to Consolidated C-87 Liberator Express transport aircraft. It was estimated that 200 C-87 flights would be required to support each VLR bomber group, with 2,000 C-87s in operation by October 1944 and 4,000 by May 1945. Five missions per group per month could be flown, with 168 group-months believed to be sufficient to destroy all targets in Japan within twelve months. The Matterhorn plan was formally approved at the Second Cairo Conference in December 1943, with a target date of 1 May 1944.
Base development India Airbases
A team headed by Brigadier General Robert C. Oliver, the commander of the China–Burma–India Theater (CBI) Air Service Command, began inspecting potential sites for B-29 bases in August 1943. The B-29's wing span was considerably wider than the of the Boeing B-17 Flying Fortress], the next largest aircraft in the inventory, and a fully-laden B-29 weighed about , nearly twice as much as a B-17. The Twentieth Air Force asked for B-29 runways to be long and wide, nearly twice the area of a B-17 runway. The plan was to enlarge and improve five existing runways in the flatlands west of Calcutta to bring them up to B-29 standards. Five airfields were selected on 17 November: Bishnupur, Piardoba, Kharagpur, Kalaikunda and Chakulia. Wolfe's advance party from the XX Bomber Command inspected the fields in December, and they accepted all but Bishnupur, for which Dudhkundi was substituted.
Work was to be carried out by U.S. Army engineer units with imported materials and local labor. Company A of the 653rd Topographic Battalion surveyed the sites to determine how the airfields could be constructed. In order to get the runways operational as soon as possible, the airmen were persuaded to temporarily accept runways long and wide. Lieutenant Colonel Kenneth E. Madsen was in charge of the construction of the air bases; Colonel William C. Kinsolving, a petroleum engineer, had the task of laying two pipelines to the airfields. They reported to Colonel Thomas Farrell, who headed the CBI Construction Service.
Each air base would require four months' work by an engineer aviation battalion. In order to meet the April deadline, the engineer units should have been in place by December, but they were still in the United States. The CBI theater commander, Lieutenant General Joseph W. Stilwell, gave them priority for shipping, and they set out on a convoy that sailed on 15 December. Travelling via North Africa, they reached India in February 1944. In the meantime, local contractors and 300 trucks were borrowed from the engineer-in-chief of the British Eastern Command.
The delay in sending the engineer units threatened to upset the entire Matterhorn timetable. On 16 January 1944, Stilwell diverted the 382nd Engineer Construction Battalion from working on the Ledo Road to working on Kharagpur. It deployed by air, taking over equipment on site. The 853rd Engineer Aviation Battalion arrived in the theater on 1 February and was set to work on Chakulia. It had lost more than half its personnel en route when , the ship it was traveling from Algiers to India on, was sunk by a radio-controlled bomb off Sicily on 26 November 1943. Units from the 15 December convoy began arriving in mid-February. The 930th Engineer Regiment was assigned to Kalaikunda, the 1875th Engineer Aviation Battalion to Dudhkundi, the 1877th Engineer Aviation Battalion to Chakulia and the 879th Engineer Aviation Battalion (Airborne) to Piardoba. As an airborne unit, the 879th was equipped with small, air-portable equipment that was unsuited to airbase work, and it was eventually reassigned.
The engineer units worked with borrowed equipment; their own unit equipment did not begin to arrive until 15 April, and was not complete until 30 June. Marshall accepted a proposal from Stilwell and the Supreme Allied Commander of South East Asia Command, Admiral Lord Louis Mountbatten, to divert units earmarked for postponed amphibious operations in Burma to Matterhorn. Accordingly, Marshall assigned the 1888th Engineer Aviation Battalion, which embarked from the West Coast of the United States in February and reached India in mid-April. With its arrival, Madsen had 6,000 engineers and 27,000 Indian civilians under contract from India's Central Public Works Department on the job.
Religious sensibilities meant that seven different types of rations had to be stocked. There were cultural sensibilities that had to be considered as well; at Chakulia, the 1877th Engineer Aviation Battalion assigned rock quarrying and rock screening to both sexes, unaware that the former was regarded as work for men and the latter was considered work for women, resulting everyone walking off the job.
Grading the runways accounted for more than half of the of the earth moved. New concrete was laid thick; existing runways were overlaid with of concrete. While sand was obtained from nearby streams and gravel and crushed basalt construction aggregate were obtained locally, Indian cement was in short supply and of inferior quality, so much of the cement used was imported from the United States. Concrete was produced locally and spread by hand at all the fields except Kalaikunda, where heavy equipment was used. Chevron- and horseshoe-shaped hardstands were provided, as were paved, rectangular parking areas. To save time and concrete, dispersal areas were omitted.
A variety of buildings were provided. At first the troops lived in tents, but later they were housed in native "basha" huts with earth or concrete floors, bamboo or plaster walls and thatched roofs. Basha huts were also used for administrative and technical buildings, along with U.S. prefabricated plywood structures, some of their Italian counterparts that had been captured in the East African campaign, and British Nissen huts. Workshops and hangars were also provided. Most of the utilities such as electricity and water were installed by U.S. Army engineers.
Although reports to USAAF headquarters frequently claimed that work was proceeding on schedule, that schedule was far behind the original plans. Works on the airbases were not completed until September. The decision in April to deploy the second wing of B-29s to the Marianas meant that only four groups would be deployed to CBI instead of the originally planned eight, so only the five original airfields were required. Delays in construction at Dudhkundi meant that Charra Airfield had to be used temporarily. The B-24 runway there was extended with Marston Mat to accommodate the 444th Bombardment Group from when it arrived on 12 April until Dudhkundi was ready in July. The total cost of constructing the five airbases was estimated at $20 million (equivalent to $ million in ).
Pipelines