The Yak-28 first entered service in the early 1960s. Four variants saw extensive service: the Yak-28 attack version, the Yak-28P Firebar all-weather interceptor, the Yak-28R multi-sensor reconnaissance aircraft, and the Yak-28U dual control trainer. The Yak-28P Firebar interceptor was withdrawn in the 1980s.
The wings are high-mounted, swept-back, and untapered from the engines to the large blunt tips. The wings have wide roots. There are two turbojet engines in pods under the wings. The pods extend well beyond the wings' leading and trailing edges. The fuselage is long with pointed, glazed nose and is tapered to the rear section. There is a bubble canopy and a belly fin under the rear section. The tail fin is swept-back and tapered with a blunt tip. The tail flats are mid-mounted on the tail fin, swept-back, and tapered with blunt tips.
The Yak-28 was rather complicated, technologically inefficient and substantial modifications were done in Irkutsk to meet the customers' requirements. According to F.R. Kugel, a veteran of the IAIA "... the manufacture of this aircraft put the biggest number of questions related to the production run at the Irkutsk Factory, in terms of production process, machining, assembly, aerodynamics and flight testing."
The Yak-28 was the first tactical strike aircraft capable of flying at super-sonic speed with full armament. The aircraft structure was not adapted to the production run capabilities and required substantial modifications. The Irkutsk factory was chosen to produce the Yak-28 that had a vast experience in mastering the production of principally new aircraft types. Higher accuracy requirements to external aircraft lines, the necessity to provide structure strength and rigidity to break the sound barrier called for further production process improvements, introduction of many changes into the structures and implementation of new flight test programs.
After the Yak-28 took part in the air parade in Tushino on May 1, 1961, 'The New York Times' wrote that the USA had nothing to be compared with this aircraft. The Irkutsk factory manufactured the Yak-28 and its modifications fitted with various equipment during 12 years. Totally, 700 bombers, fighters, trainers, reconnaissance and other type of aircraft were produced.
The Yak-28 bomber was a further development of the Yak-25 and Yak-27 aircraft. The first flight was made on March 5, 1958 by test pilot V.M. Volkov.
The bomber armament comprised the NR-23 (23 mm) gun and a higher speed firing two-barrel GSh-23Ya (23 mm) mounted on later or upgraded aircraft. The bomber armament was placed in the fuselage bay. The normal armament load was 1000kg, maximum load -3000 kg, maximum bomb calibre - 3000 kg. In 1962, the Yak-28U trainers with two separate cockpits and dual control were manufactured in Irkutsk (183 aircraft).
In the mid-1950s, the requirements of combat aircraft changed almost every six months, which largely contributed to advances in engine building. Therefore, in the middle of the test Yak-26, March 28, 1956 issued a decree of the Central Committee of the CPSU and the USSR Council of Ministers #424-261 (MAP #194 order of 6 April), which forced the OKB-115 design and start construction on its base a new light high-altitude supersonic front bomber. According to this decree, the plane with a crew of two people should be equipped with two engines P-11-300 OKB S.K.Tumanskogo with a thrust of 3900 kg at maximum capacity and 5300-5500 kgf in afterburner.
The machine had the following basic requirements: take-off weight - 12000-13000 kg; the maximum speed at an altitude of 10,000 meters on the afterburner - 1500-1600 km / h (without afterburner - 1200-1300 km / h); the climb 10,000 meters in afterburner - 3-3.5 m; service ceiling - 16000-17000 m; run - 1000 m run - 1100 meters; range at an altitude of 10,000 m with a bomb load of 1200 kg (special products) - 2200-2400 km; normal bomb load - 1200 kg, overload - 3000 kg. To reduce the risk of back injury hemisphere needed to equip the aircraft with aft gun mount 23-mm gun and ammunition to 50 rounds. Design bomber was carried out under the code of the Yak-129.
At the very beginning of work on August 15, 1956 the Council of Ministers issued a decree #1115-578 (IAP order #453 of August 21), according to which the DB-115 is also instructed to develop a version of the aircraft by two very powerful engine VK-11 with a thrust to the maximum Mode 6,100 kg and 9,000 kg on the afterburner. This significantly increased the requirements for LTH bomber. Thus, the maximum speed on afterburner was increased to 2500 km / h, service ceiling - up to 20000-21000 m range at an altitude of 14000-15000 m at a speed of 1000 km / h - up to 2500 km and flying at 19000- 20 000 m - 2000 km (the 500-600 km - at a speed of 2000 km / h and 1400-1500 km - at a speed of 1000 km / h). The first of two prototypes should present to the factory tests in the I quarter of 1958, and in the IV quarter - on state tests. It was assumed that the VC-11 will be installed on heavy interceptor Sukhoi Design Bureau (T-37) and OKB Mikoyan (E-150), but he was not claimed, and for this reason did not run into production. Therefore, the task of installing it on the Yak-129 was removed.
The first flight of a new aircraft on March 5, 1958. In its air lifted chief test pilot OKB V.M.Volkov. From that day began factory testing machines, which were held at the airport LII and ended on October 4. By the time the new designation was assigned a serial bomber Yak-28. The plane got NATO code name Brewer-A (Brewer). Also Volkova, the aircraft overflew the test pilot plant #30 S.G.Petuhov and lead pilot LII S.N.Anohin.
Compared with the Yak-26, a new bomber takeoff weight increased to 12885 kg (normal bomb load of 1200 kg and 3200 kg of fuel left). Afterburner was able to reach a top speed of 1500 km / h. It was supposed to reach a ceiling in the 17,800 meters, but because of the self-switching afterburner achieved only 16,300 m. The pilots noticed quite satisfactory stability and control, good takeoff and landing characteristics (run and run ranged from 850 to 950 m). Re-assembly of the bow cockpit was approved factory not only for pilots, but also navigators. During the tests to improve the longitudinal stability at the root of the wing and the aerodynamic ridges HCHF installed. In addition, by analogy with the second prototype Yak-27R extended wingtips, which became the advocate for the rocker-wing fairing supports.
The second prototype (Yak-28-2) also got a serial remake of the Yak-26. From Yak-28-1 aircraft differed mainly new engines R-11AF-300 with a thrust in afterburner at 5750 kgs. Their use is required to develop new gondola with increased cross-sectional area, and air intakes oval. At the entrance to the air intake was established the central body of the new design, and the output of the engine nacelles - Laval nozzle, which, according to estimates, was to provide extra traction.
These nacelles were developed under the leadership of new chief engine department OKB Polikovskiy professor, former head of CIAM. When the trial began, it became clear that the acceleration of aircraft from M = 1.3 to M = 1.6 was very slow, and attempts to reach a maximum speed associated with fuel consumption so large that it may not be enough to return to the airfield. To reduce the loss of air intakes equipped with central cone-off, which was put forward when the speed corresponding to M = 1.45.
The Yak-28-2 carried out a number of other improvements. In particular, the resettable stabilizer was added. Wing skin at the root portion of the initiative after consultation TsAGI was replaced by steel. Checking the basic flight characteristics showed that the maximum speed of the aircraft near the ground is 950 km / h and at an altitude of 12,000 m -1250 km / h. During the test pilot OKB V.P.Smirnov flew to "Tretyakov" - one of the suburban unpaved airfields, which made landing and take off from unpaved runways with cement mock bomb weighing 1500 kg. After this test pilot and navigator N.M.Shipovsky S.G.Petuhov flew the bomber to Saratov, where it carried out jointly with the military bombing at supersonic speed.
After finishing precision bombs to reset norms subsonic bomber, the main efforts focused on refining the nacelle and research new nozzle. However, even before their completion, the General Designer, inspired by the first success, decided to pass theaircraft in the GK NII VVS on state tests. The Institute's leading pilot of this machine has been assigned to the n-F.M.Sobolevsky, navigator - A.M.Halyavin.
In one of the operations on the airplane fuel disconnection occurred, and then the crew made a safe emergency landing on the ground outside the airport. For heroism in the rescue of the prototype, the crew was awarded the Order of the Red Banner.
Despite the incident, the whole state tests went pretty quickly, because the Yak-28 was the only bomber at that time capable at altitudes of more than 10,000 m with a bomb load of 1200 kg to fly at a speed of about 1400 km / h. The third pilot vehicle Yak-28-3 (yellow tail number "56" was also allegedly converted from serial Yak-26 with the same tail number) for the design was similar to the second. She also participated in the trials.
Soon followed the decision to start serial production of the aircraft in an aircraft factory in Irkutsk. To assist this the enterprise directed a group of employees of OKB-115. The first production Yak-28 (a product "B") is not much different from the second prototype. Sights on them were limited, because the bombers were equipped with a telescopic sight, because radar has not yet been implemented in the series.
In 1960, the production Yak-28B front-line bomber was manufactured at the Irkutsk factory. The Yak-28 was the first serial tactic strike aircraft capable of flying the super-sound speed with full armament. The aircraft was equipped with the OPB-115 optic sight and RBP-3 radar bombsight. The production Yak-25Bs were tested by test pilots E.N. Tcheltsov, G.M. Kurkai, G.I. Starostenko, N.N. Ivanov, V.S.Prantskyavitchus, G.E. Bulanov, A,M. Yaroshevitch, V.P. Naurov.
In total, attack units received about 350 Yak-28 of various modifications. In the mid-1970s the Yak-28 aircraft began to give way to the next generation of aircraft Su-24. The Yak-28 left its mark in the history of aircraft. By itself it created such different purposes production aircraft based on a glider - a rare phenomenon in the Soviet aircraft industry. And abroad, there were few such examples.
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