Rocket K-25 ("product 370")
The background to the development of this rocket almost repeats the events that led to the creation of the K-13 rocket. Again, in the course of a local war in the Far East, a trophy sample of modern American technology in a relatively intact condition went to the armed forces of a country friendly to the Soviet Union. The scale of the long-term war in Vietnam is incomparable with the quickly ended conflict over the Taiwan Strait. The presence of Soviet specialists in Southeast Asia was not an episodic but a permanent one. Our compatriots quickly got acquainted with the missiles taken by the Vietnamese from the Phantom, which sank at a shallow depth near Haiphong, and from other downed American planes.
Captured samples of "Sparrow" allowed from the second half of 1966 to begin work on the reproduction of the next overseas sample under the designation K-25. A full-scale R&D project on the K-25 was deployed by order of the party and government of November 13, 1967. Despite the fact that by this time the development of the Soviet "counterweight" of the Sparrow - the K-23 missile - had been under way for almost four years, copying a workable American model reduced the degree of technical risk and opened up the prospect of a 1.5-fold lightening of the MiG-23 missile armament.
But at the end of the initial stage of work, the similarity of the stories of K-13 and K-25 is interrupted. Over the past decade, the level of development of rocketry in the Soviet Union has increased immeasurably. If in 1958 the only K-5M air-to-air missile was in service with the Soviet Air Force, then by the end of the 1960s. In addition to the "thermal" and "radio" versions of the K-13, our aviation arsenal has been replenished with missiles of the R-8 / R-98, R-4, R-55 families; tests of the K-40 were completed. Deployment of work on K-25 by a team of designers headed by VT Korsakov did not stop the development of its direct competitor K-23, which was carried out in the same design organization - MKB Vympel - under the leadership of VA Pustovoitov. The homing head was developed by the team of NA Viktorov.
Copying the American model required not only the reproduction of a specific design, but also the organization of the production of extremely identical materials and, which is much more complicated, the element base of the onboard equipment. In addition, this equipment should be linked to the Sapfir-23 airborne radar. Already at that time, the Americans were completing the development of a more advanced version of the "Sparrow" AIM-7R [sic - this should be AIM-9F] Reproducing the previous modification, Soviet specialists deliberately doomed themselves to lag behind the United States ... For a number of decisions, the American missile was clearly inferior to the K-23. In particular, it used a more susceptible to interference seeker with conical scanning, and not the monopulse used for our K-23.
However, there were also enthusiasts of playing "Sparrow", in particular, the head of "Vympel" AL Lyapin, according to EA Fedosov, more a technologist than a designer, was fascinated by the success of the copying of "Sidewinder" carried out under his direct supervision.
"Sparrow" itself carried a number of generally ambiguous and unusual technical solutions for our rocketry, not mastered at the level of products launched into a series. First of all, this refers to the general scheme of the "rotary wing" missile, previously implemented in the K-9, which, as is known, had not reached the stage of testing in a controlled flight. In comparison with the normal scheme adopted on the K-23, it provided more favorable guidance dynamics, especially at the final stage of flight before hitting the target, but it was characterized by worse aerodynamic quality and required the use of a powerful hydraulic system that had not been previously used on Soviet air-to-air missiles. steering drive.
Structurally, the K-25 ("product 370") repeated the American prototype. Behind the semi-active radar seeker DV-109 were located a proximity fuse, U-98 autopilot equipment, a power supply and steering drive unit, and a core warhead. The solid-propellant rocket engine was located in the tail section of the rocket; constructive measures to narrow the range of flight alignments (for example, a nozzle with an elongated gas duct) were not provided.
At the beginning of the development of the K-25, it was decided to use domestic counterparts with seemingly similar characteristics instead of some American materials. However, they did not ensure the operability of a number of systems and units, which significantly slowed down the process. In 1970, with the completion of the stage of autonomous development of K-23, MiG-21 PF No. 1203 was released, which was re-equipped for K-25 (the so-called E-7 with K-25). But due to the unavailability of the engine and steering gear, the K-25 was late, and the MiG-21 was used to study another "American" - the K-13M. The following year, the MiG-21 was again equipped with the APU-25-11 and fully prepared for autonomous missile testing.The equipment of the MiG-23M (No. 606 and 607) APU-25-23M, made according to the type of improved launchers for K-23,
Only at the beginning of 1972 did they begin factory tests (autonomous launches from the MiG-21), which were completed in March of the following year. In total, 20 launches were made in 1972. According to the results of tests with the MiG-23, three launches on parachute targets revealed a defect in the seeker DV-109A, which had to be refined. In 1973, the main volume of factory tests was carried out: 16 launches, including launches of telemetric and combat missiles at parachute targets and at La-17. However, by this time, flight tests of the K-23 on the MiG-23M had already been completed.At the beginning of 1974, it was planned to fire on the MiG-17 at low and high altitudes, but with the adoption of the K-23 into service by a joint decision of the Air Force, the Ministry of the Aviation Industry and other departments,
For some time, the K-25 was supposed to be used as weapons for more promising fighters. But it soon became clear that the use of a rocket designed overseas a decade and a half ago was incompatible with the achievement of the superiority of the domestic IV generation fighters over their American counterparts.
Nevertheless, work on the K-25 was not completely fruitless. A number of developments, in particular, research on an aerodynamic scheme close to a rotary wing, and on a hydraulic steering drive, were used in missiles of the K-27 family.
