1933 Project A - XBLR
The 1920s and 1930s were the "golden age" of aviation. The aviation technology developed rapidly with ranges extending beyond a thousand miles. Large seaplanes traveled to and from the two sides of the Atlantic. The flight distance record was broken and often became the headline news of major newspapers. During this period, the development of long-range bombers made great progress, but it was the Soviets who really led the Americans in developing heavy bombers. From September to October 1929, a Soviet-made Tupolev TB-1 (ANT-4) bomber flew over the United States during the global flight, causing concern among many Americans.
The story of the Army's long-range bomber has its beginning in proposals of 1933 for the construction of an ultra long-range bomber that immediately would have relegated such a plane as the B-17 to the category of medium range. Equally significant is the fact that the proposed plane was intended for a mission of coastal defense and that the proposal was advanced under circumstances decidedly favorable to its acceptance.
The introduction of the airplane as a weapon of war had brought confusion and sharp debate into areas of defensive responsibility theretofore clearly enough defined. Defense of the coast traditionally had been an Army function; it fortified and manned positions of obvious importance to the defense of coastal cities and other areas of special strategic significance, and it was expected to take such additional steps as were required to repel an attempted invasion across the coast line.
The Navy, on the other hand, placed a high premium on the mobility of its fleet, and, while necessarily dependent upon shore installations, it avoided commitments for coastal defense that would tend to tie down the fleet. Even the defense of naval shore installations was a primary responsibility of the Army. Because of the limited range of coastal defense weapons and an obligation for the safety of shipping, however, the Navy necessarily assumed certain responsibilities for the protection of coastwise sea lanes. But the Navy's obligations, in contradistinction to the Army's, were limited, and it was readily admitted that final responsibility within the range of land-based weapons lay with the Army.
The airplane, of course, effectively extended the range of the Army's land-based weapons, and, in so doing, it gave to that service the means to extend its operations in defense of the coast over an element heretofore regarded as almost exclusively the Navy's responsibility. At the same time, the airplane offered to the Navy a new weapon of growing potentialities in the performance of such traditionally naval functions as patrol of coastal sea lanes. Placed aboard a carrier, the airplane could be regarded merely as a new element of the fleet, but the land-based plane carried certain advantages in the fulfilment of some missions at sea.
In the development of service aviation, consequently, there was a tendency for the Navy to move ashore and for the Army to extend its activities beyond the shore line. Thus the War Department announced on 9 January 1931 the conclusion of an agreement between Gen. Douglas MacArthur, Chief of Staff, and Adm. William V. Pratt, Chief of Naval Operations, intended to leave the air force of each service "free to develop within well defined limits and each with a separate and distinct mission".
On July 3, 1933, the Soviet Union's TB-4 (ANT-16) bomber completed its first flight. The wingspan of this giant aircraft was 54 meters, almost twice the size of the Keystone B-5. Despite the fact that its voyage did not increase much more than TB-1, this fact was unknown at the time. The Americans who were concerned about this incident suddenly discovered that the Soviet bombers were not only twice as large as the American aircraft, but also adopted the advanced all-metal cantilever monoplane design, while the United States still used the biplane of the canvas skin structure. The strict confidentiality measures of the Soviet Union made the outside world greatly overestimate the actual performance of the ANT-20.
Through the 1930s many aviation experts believed that the bomber would always get through. In the early 1930s this idea was at least partly justified. Modern bombers of the period could reach 200mph, and could outpace the fighter aircraft of the day. With no radar to provide advance warning of an enemy attack, an interceptor aircraft would need to be significantly faster than the bombers it was attacked, and no such aircraft yet existed. There was also a belief that fighters fast enough to intercept 200mph bombers would be too difficult to be “efficiently or safely operated either individually or in mass” (General Westover).
In the mid-1930s, airmen were ignorant of radar and, except for a few die-hard attack and pursuit enthusiasts, gave heavy bombers first priority. With the B-10 they were beginning to get the speed they wanted; now it was time to go for range. At Wright Field in 1933, the Materiel Division sought to determine if it was possible to build an aircraft capable of carrying a 2,000-pound bomb load 5,000 miles (five times the range of the B-10). A bomber with such range would solve the hoary problems of reinforcing the air forces in Hawaii, Panama, and Alaska. Designated Project A, the study received General Staff approval, and Boeing and Martin were asked to submit designs and engineering data. Range was very much a question of size. The plane had to be big enough, with a wing span wide enough to carry the fuel load for range.
That the bomber would have the first call in the development of new equipment, and that the trend of thought favored a combination of the reconnaissance and bombardment function in one plane, was suggested by an engineering study, undertaken in July 1933 by the Materiel Division at Wright Field, of the problem of "maximum range" with "a 2,000 pound bomb load." The result of that study indicated that a range of 5,000 miles at a speed of 200 miles per hour was practicable.
Accordingly, in December 1933 the Air Corps submitted to the War Department in its so-called Project A - a proposal to build a plane of that range. In support of the proposal it was pointed out that such a plane would "not alone reinforce either coast line . . , but would definitely enable ... reinforcement of... Panama and Hawaii."
The action of the War Department General Staff was prompt enough. Tentative approval having been given on 19 December 1933, a $609,300 Air Corps budget for long-range bomber development was approved "in principle" on 12 February 1934, and on 12 May the Chief of Staff authorized the negotiation of contracts with the Boeing and Martin companies for preliminary designs and engineering characteristics for the new 5,000-mile-range bomber, approved by the General Staff on 16 May 1934, were adjusted to a tactical mission for "the destruction by bombs of distant land or naval targets" and a purpose "to reinforce Hawaii, Panama, and Alaska without the use of intermediate servicing facilities."
On 24 April 1934, the Soviet Union launched the largest aircraft at that time, the ANT-20, designed by Tupolev, which was once known as the Maxim Gorky, which celebrated the Soviet Union. The 40th anniversary of the famous work of the famous writer was specially made, and the manufacturing expenses came from social donations. The wingspan of the ANT-20 is 64 meters long, making all contemporary aircraft dwarf. The eight-engine air behemoth is a flight propaganda station with a kitchen, movie screening room and printing shop. Due to the large size, there was no hangar at that time to accommodate the Maxim Gorky.
Boeing's Type 294 and Martin's Type 145 were named XB-15 and XB-16 by the military. The power unit of the two machines is the 1000 hp Allison V-1710-3 inline engine. The Boeing 294 is a traditional all-metal monoplane with the engine at the leading edge of the wing. The Martin 145 used a rare double-tailed twin-rudder layout. The two engines on the inside and outside of the wing are mounted on the leading and trailing edges of the wing to drive the propeller. Martin's plan was also equipped with the first three-point landing gear that was not common at the time. Martin's plan was larger than Boeing's, with a wingspan and total weight of 52.7 meters and 45360 kilograms. The Boeing 294 was only 45.4 meters and 29500 kilograms. Both aircraft are smaller than the Maxim Gorky, but they were already the largest aircraft ever designed in the United States.
June 1934 saw completion of the preliminary contracts with the Boeing Aircraft Company, and a year later a contract was closed for the purchase of one XB-15, as the projected plane had now come to be designated. The plane itself was not completed until the fall of 1937, and subsequent tests proved that its size and weight had been conceived on a scale too ambitious for the power plants then available. But Project A became the parent, too, of the B-17, the B-24, and the B-29, to mention only those heavies which carried the weight of the bombing attack on Germany and Japan in World War II.
There was a close connection between key dates in the origin of the heavy bomber program with other major developments affecting the role of the Air Corps in national defense. The report of the Drum Board, with its recommendation of a GHQ air force, had come in October 1933, just after the circulation of proposals which led to the B-17 and only a short while before the submission of Project A for approval by the War Department. In July 1934 the Baker Board made its report, and, in keeping with its recommendations, the GHQ Air Force was activated in March 1935 - before the drawing of a final contract for the XB-15 and some four months before the XB-17 underwent its initial flight test.
There is in this sequence at least the suggestion that Air Corps leaders may well have been influenced to accept a compromise on the aggravated question of organization because of the hope that they might thus clear the way for a long-range bomber program. Whatever the case, the Air Corps after 1935 was characterized not so much by its concern to change the basic organization of national defense as by a purpose to find in the mission assigned to the GHQ Air Force the basis for an ambitious program of bomber development. The Army airman thereafter was, above all else, an advocate of the big bomber, and around the potentialities of that type of plane he built his most cherished hopes.
After reviewing the plans of the two companies, the Martin 145 was eliminated. However, Martin's experience and technology gained from other projects have successfully developed the PB2M-1 "Mars" large seaplane.
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