The Boeing R-12 was one of the most famous and most numerous among the fighters of the US Army Air Corps during the period between the two world wars.
History This fighter originates from a pair of experimental aircraft released by Boeing as a possible replacement for Army PW-9 and deck F2B and F3B. These two progenitors of the P-12 / F4В line wore the brand designation “83 model” and “89 model”. Their main difference from previous Boeing fighters was the use of bolted duralumin airframe instead of the previously used welded steel pipes. They retained the welded steel structure of the motor mount and the central section of the fuselage, and the tail section was made of duralumin tubes. Bolting pipes used by Boeing before, but only on steel structures.
The wing of the "83 / 89" model had a straight shape in terms of instead of the tapering edges adopted on earlier Boeing aircraft. Designers have chosen for the wing corporate profile "Boeing 106" of recent development. The tail part of the fuselage was a semi-monocoque, metal structure with duralumin corrugated skin, first used on the FCV-1.
The armament could consist of either two synchronous 7,62 mm machine guns, or one 7,62 mm and one 12,7 mm machine gun. Pratt & Whitney R-1340-7 450 hp air-cooled engines were used as the power plant. with a two-blade propeller of variable pitch on the ground. There was no engine hood, but there was a small fairing behind each cylinder. Between the landing gear, under the fuselage, it was possible to hang a two-hundred-liter additional fuel tank. In addition, the plane could lift up to 300 kg of bombs.
"Model 83" was first flown around June 25, 1928 in Seattle, and a few days later delivered the fleet in San Diego. The Model 89 was completed a month later and sent by rail to the Fleet Test Center in Anacostia, Maryland. The first time she flew on August 7th. Both aircraft were almost identical, only on the “Model 83” the main landing gear were with a common wheel axis and had struts, and on the “Model 89” the landing gear performed with separate axles. Although the experimental aircraft did not accept the fleet's balance sheet, they, for purely bureaucratic purposes, received the official designation XF4B-1. Since both copies belonged to Boeing, they did not have a military mark, as well as a civilian mark.
Both aircraft were originally equipped with the long-nosed R-1340В engine, which was expected to improve the aerodynamics of the fighter. Soon they were replaced with standard ones, which had practically no effect on flight data.
Flight tests of these two aircraft have shown that they are superior to all fighter aircraft in service. As a result of the 19 June 1929 of the Year, the fleet ordered a pattern of "83 models" and "89" 27 serial F4В-1. The designation XF4B-1 for experienced aircraft has now become official. Both prototypes were returned to Boeing for refinement following the model of the serial F4В-1.
The first serial F4В-1 was made as a personal plane by the assistant fleet secretary David Ingells - the only ace of the fleet during the First World War. All the armaments were removed from the aircraft, the hood was installed and painted blue, which is characteristic of fleet demonstration aircraft. The aircraft thus received the designation F4В-1А.
Although the "83" and "89" models were originally presented to the fleet, the "89" model was also tested by army pilots at Bolling Field, on the other side of the take-off field of the fleet test center in Anacostia. Army aircraft like. As a result of a positive test report, Boeing 7 November 1928 of the year received a contract for ten P-12 (brand name "model 102"). The army order was unusual in that the army did not even have a test aircraft for testing, confining itself to only test flights on a naval aircraft.
The first nine P-12 were modeled on fleet F4В-1, except for the removed landing hook and specialized marine equipment. 26 February 1929 The first P-12 was handed over to captain of the army air corps, Ira Eiker. The aircraft was designed specifically for friendly flights to Central America. These serial P-12 were the only ones among the line of the army version of the fighter, which retained the ailerons on the model of experimental machines. Serial fighters also got fairings behind the engine cylinders, but due to cooling problems, they were almost immediately abandoned.
The latest serial P-12 was already supplied under the designation XP-12А ("101 model") with various modifications, according to the reviews of army pilots. The main differences were: aleron by type of fraze; shorter landing gear; extended engine hood; A new elevator and a freely oriented tail crutch, instead of a fixed one. For the first time, the XP-12A was lifted into the air on 11 on April 1929. However, he flew only four hours since May 18 collided in the air over Wright Field with another P-12. However, the tests of the remaining machines allowed to eliminate the small flaws of the fighter.
The P-12B was the result of a modification of the fighter based on the experience of operating nine P-12s in the army. 10 June 1929 r Boeing received an order for 90 P-12В, which became the largest order after the First World War. The aircraft received the brand designation “model 102В”, and differed from the standard P-12 with aprons aprons, a new elevator and slightly increased wheels of the main supports. The chassis remained the same, the engine hood was also not set. True, the aircraft later modified "B" still got a Townend ring, designed for the latest versions of the fighter. New fighter aircraft in disassembled form began to be supplied to the army from February 1 1930. The P-12B was somewhat heavier than its predecessor, and its characteristics decreased accordingly. Armament left like the P-12.
The further development of the fighter was the P-12C, which received a new model of the R-1340-9 engine and various modifications in the design. 2 June 1930 The army ordered 131 P-12C (the brand designation for "222 model"). The naval version of this model was the F4B-2. The P-12 had a Townend ring and chassis modeled on the “83 model”. And the chassis passed the test on the prototype of the XP-9 fighter. Navigation lights appeared on the wingtips. The supply of the army of the disassembled P-12C began on August 30 of the year 1930. According to the original project, the first 96 ordered aircraft were completed, and the remaining 35 were completed as P-12D. Their shipments began on 25 February 1931 of the year and ended on April 28.
P-12D outwardly did not differ from P-12C. On it the ignition connector was installed in front of the engine of the new modification R-1340-17. In addition, the P-12D removed from the hood additional support racks. Later, the fighters of models "C" and "D" got the keel on the model of the P-12.
Everyone understood that with such minor modifications a noticeable increase in performance could not be expected. Despite the fact that the United States did not plan to wage any large-scale wars in the coming years, the leadership of the Army Air Force could not fail to note the fact that in Europe the modernization of the aircraft fleet went faster. For example, the Soviet fighter I-4 and the English Bristol “Bulldog” Mk.I of the 1928 release of the year could reach speeds of 280 km / h, and the French Devuatin D.27- came close to the 300-km line. In addition, the construction of high-speed monoplanes has already been launched since 1932, leading to the emergence of such famous and successful fighters as the I-16 and D-500. And yet, the US Air Force was not in a hurry to part with the biplanes, especially since the designers of the Boeing company very promptly proposed an improved fighter, the 218 model, which became the most well-known variant of the P-12 fighter.
This modification was developed at the initiative of the company and circled around 29 September 1930. On the "218 model" the company planned to work out a number of new solutions for the P-12 / F4В series. The aircraft received the fuselage of an all-metal semi-monocoque design modeled on the experienced XP-9. Instead of a crutch was installed tail wheel. Behind the cockpit mounted gargrot. Vertical tail was first performed on the model of the P-12В, but soon its area was increased - the steering wheel and the keel outwardly "rounded". The new aircraft received the army designation XP-925, which, after replacing the engine R-1340D on R-1340, became XP-925А. The empty weight of an experienced fighter was 888 kg, take-off - 1223 kg. With the R-1340D engine, the speed at the height of 2440 m was 312 km / h. In addition, to further increase the speed on the "model 218" installed chassis fairings.
"Model 218" was tested by the army and navy, while the aircraft wore civil registration X66W. At the end of the test, this aircraft was sold to China. Using the 218 model as a model, the 3 army in March 1931 ordered 135 aircraft that received the designation Р-12Е (the brand designation for "234 model"). The deck version of the aircraft carried the symbols F4В-3 and F4В-4. From the previous model, the new car differed only in a semi-monocoque fuselage and tail, like the "218 model". Initially, the fighters of the “E” modification had a tail crutch, but in the process of operation it was replaced with a tail wheel. The P-12E first carried inflatable bags in the upper wing to ensure unsinkability during landing, but then most of the fighters received an inflatable rubber rescue raft placed in an enlarged gargrote behind the pilot. This gargrot was called "Panama", as it was intended for aircraft operated in the area of the Panama Canal.
The latest 25 aircraft under the 1931 contract of the year were equipped with an R-1340-19 engine, which developed the maximum power of the 600 hp. at the height of 3050 m - on 1000 m higher than R-1340-17. Since this refinement significantly affected the flight data of the fighter, these 25 machines received the designation P-12F ("251 model"). Deliveries of the new modification were carried out from 6 March to 17 in May 1932. The last 10 P-12F received a tail wheel instead of a crutch, which was later installed on all previously released aircraft versions "E" and "F". Most P-12F also got behind the cockpit of the "Panama".
The last aircraft of the P-12 series was equipped for experimental purposes with a closed cockpit canopy with a sliding back panel. Serial production of the fighter P-12 ended on the model "F". All subsequent modifications were modifications of earlier versions.
The Boeing fighters entered the 17 Fighter Group (34, 73 and 95 Squadron) at Machfield and the 20 Fighter Group (55, 77 and 79 Squadron) for Fighter Squadron (12-I, 3-I and 16-S Fighter Group) (24-I, 29-I and 745-I Squadron) for the Fighter Group (79-I, 18-I and 6-I Squadron) for the Fighter Group (19-I, XNUMX-I and XNUMX-I Squadron) and XNUMX-XNUMX Squadron -field As they grew older, P-XNUMX was transferred to overseas units: the XNUMX Squadron in the Philippines; The XNUMX Fighter Group (XNUMX-I, XNUMX-I, XNUMX-I and XNUMX-I Squadron) in the area of the Panama Canal; The XNUMX Fighter Group (XNUMX and XNUMX Squadrons) in Hawaii.
The pilots were pleased with the Boeing, however, it soon became quite clear that the P-12 has a clearly outdated design, including morally. The most striking example that proved the inability of the P-12 to effectively counteract the newest monoplanes in any way was the exercise that took place in May of the 1933 year, during which the actions of several types of troops were practiced. During the exercise, the six P-12 was allocated for the interception of bombers Y1B-9A, who, having found the fighters, just fired and got away from the pursuers. With the advent of Martin B-10 and B-12 high-speed bombers, the difference in speed became even more noticeable and reached 50 km / h. As a result, almost all of the P-12 to the 1936 year was replaced by P-26А. After that, they were mainly used as training machines. In 1941, most of the remaining P-12E and P-12F were sent to technical training schools. After the States entered the Second World War, 32 P-12 of various models were transferred to the fleet for use as radio-controlled targets. In the fleet, they received the designation F4В-4А, where "A" denotes the military origin of the vehicles. Most of them were destroyed during the fire training of pilots.
Little is known about the P-12 service in other countries. Specially for export deliveries, the Boeing developed the “Model 100E“. The aircraft was intended for delivery to Thailand, but the contract was never concluded, and subsequently one of the two built copies was sold to Japan. In 1932 for the marine aviation Brazil were allocated 14 deck F4B-4. These aircraft received the designation “model 256” and were equipped with a “Panamanian” headrest. In 1933, another batch of 9 cars was sent. The Brazilian Boeings were in service until 1941 and did not take part in wars.
The only prototype of the P-12 “model 218“ was the only car out of all the numerous variants that had to “smell gunpowder”. Immediately after the end of the tests in 1932, he was sold to China, who expected to test the fighter themselves to decide on the purchase of a larger lot. However, the new invasion of the Japanese, which began soon, mixed these plans. During the next air strike on Shanghai, American volunteer Robert Short flew to intercept a group of three Japanese planes. He managed to knock down two of them, but his P-12E also fell to the ground as a result of the battle. Although the Chinese pilots were impressed by the courage of the American and the capabilities of the Boeing biplane, the choice was eventually made in favor of other aircraft.
There is no exact information about fighters handed over to the Philippine air forces. At the end of 1941, they included a pair of P-12 and a dozen P-26. In the first days of the war, only P-26А rose in the air, which was the case with the old biplanes at that time, is unknown.
One P-12 in 1940-1941 was used in a civilian school, and then it was acquired by the Air Museum in Ontario, California, at the California Polytechnic Institute. It was slowly restored, and in the year 1962 brought to flight status. Now the plane is in the building of the museum of the airport Chino in California.
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