German aircraft designers were tasked with making prototypes of EF-131, EF-132, EF-126 and EF-140 aircraft (EF - Entwicklungs Flugzeug, which means "experimental aircraft"). The bomber EF-131 (Ju 131) was made on the basis of the German bomber Ju 287. This aiarcraft became the world's first heavy aircraft with a swept wing. At the same time, the sweep of 20° was an inverse, and not a traditionally straight line, to which the Soviets were so accustomed. Only in the 1990s were there American and Russian machines with reverse sweep.
The experimental machine Ju 287V1 and the Ju 287V2 and Ju 287V3 that were being built were captured by Soviet troops. Based on the Ju 287V2, the OKB-1 in Dessau began to design the EF-131. In January 1946 preparations began for the assembly of the prototype. Some aggregates, in particular the wing compartments, were taken from the Ju 287V2, but most of the parts were made anew. Because of the great complexity of the work, we decided to limit ourselves to the construction of three copies: two (VI and V2) for flight tests, and one (V2) for strength tests.
On April 17, 1946, the Resolution of the Council of Ministers No. 874 was issued by which the USSR Ministry of Fuel and Energy undertook to complete the construction of a prototype of a jet bomber "Junkers-131" with six engines "YUMO-004" at OKB-1 in Dessau, with a maximum speed of 860 km / h , with a range of 1050 km and a bomb load of 2000 kg. The deadline for the completion of the construction of the prototype is September 1946. On August 12, 1946, the Junkers-131 aircraft was completed by construction and transferred to a flight test station for finishing operations and the beginning of ground tests.
"Junkere-131" (EF-131), like its prototype Ju 287V2, was a three-place monoplane with a swept wing - 19 ° 50 '. Profile - the plant "Junkers", with a relative thickness of 12.5%. On the wing were slotted flaps and slats. The use of the hermachine allowed pilots to fly the aircraft at high altitudes without special equipment. The large glazing area of the cab provided a good view forward and down.
But for all the external similarity of the EF-131 was not an exact copy of the German bomber. Its fuselage was longer by 2.5 m, differed in size and tail fins, the shape and design of the fenders were changed to ensure the automatic withdrawal of the aircraft from the overcritical angle of attack. The normal take-off weight of the EF-131 was 22,955 kg. The aircraft was equipped with six turbojet engines Jumo 004V with a thrust of 900 kg each. The reserve of fuel was 7150 kg. Armament: a tail machine gun turret (two 13 mm MG-131 machine guns). To accelerate the take-off, the use of seven launch accelerators with a thrust of 1000 kg was envisaged.
August 16, 1946 bomber EF-131V1 was transferred to flight tests, but no flights were conducted. In September, the aircraft was dismantled and sent to the USSR, in the LII.
April 15, 1947 issued an order MAP, which pilot plant number 1 in the Sub-Rivers was entrusted until the end of July 1947 to test the bomber EF-131. At the end of 1946 the first copy of EF-131 was delivered to LII, and the second copy was assembled in parallel at the plant No. 1.
On May 23, the EF-131 flight tests began. These machines can be considered the first Soviet jet bombers. According to the report of the LII: "The take-off of the plane during take-off, the flight for 15 minutes and landing were conducted well. The aircraft was piloted by the German pilot Paul Yulge - test pilot of the pilot plant No. 1. According to the pilot's conclusion and observations from the ground, the aircraft had good flying qualities within the limits of the mission for the first flight. The plane took off at a speed of 250 km with a flight weight of 17 tons. The maximum speed, due to the program of the first departure, was 350 km and the landing speed was 220 km, the horizontal flight was carried out at an altitude of 1,400 meters. "
Until October 1947, seven flights with a total duration of 4.5 hours were conducted on the EF-131 bomber. German pilots P. Yulge and G. Shreider from OKB-1 participated in the tests.
In October 1947, in connection with the ban on the stay of foreign specialists at sites conducting secret work, an order was issued banning the testing of German aircraft in the LII and returning to the plant both aircraft and German specialists. All winter, the EF-131 and EF-126 aircraft stood at the aerodrome in the rain and snow, which led to the failure of many rubber parts and electrical wiring. It took repair, which took a long time. Only in May 1948 the planes were transported to the Moscow military airfield in Teply Stan where they were ground tested. And by order of the MAP of June 21, 1948, all work on the EF-131 bomber was stopped.
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