Russian missile design house Vympel unveiled two previously classified air-to-air missiles (AAMs) at the show, the K-37 long-range active-radar-guided AAM and the K-74 infra-red-guided short-range missile.

The K-74 is a development of Vympel's R-73 (AA-11 Archer), with the main difference being an improved infra-red (IR)-seeker. Both have the same basic airframe.

The K-74 seeker has a maximum off-bore-sight angle of 60¹, compared to 40¹ for the basic R-73. The design bureau adds that, as a consequence of using the improved Arsenal design bureau IR seeker, maximum engagement range is improved by around 30%.

Along with an improved seeker design for the K-74 (the K designator denotes that it has yet to enter service with the Russian air force), Vympel says that it looked at alternative thrust-vector designs.

Three thrust-vector configurations were considered: the twin inceptors fitted to the basic R-73, an all-moving nozzle, and four independent inceptors.

While the four-inceptor design proved to be the lightest, it was also the least robust, and the all-moving nozzle suffered from hot-gas leakage through the spherical seal. Vympel opted to continue with the approach initially used on the R-73.

Work on the K-74 is understood to have begun in the mid-1980s. Vympel is also offering an upgrade which would take the K-74's improved IR seeker and marry it to an air-force inventory of R-73 airframes.

Vympel also displayed an R-73 with a laser fuze, and says that this variant is already in service with the Russian air force.

While the K-74 is likely eventually to enter the air force inventory, the future of Vympel's other debut weapon is in greater doubt.

The K-37 is the successor to the R-33 (AA-9 Amos) and was intended to provide the primary AAM armament of the upgraded Mikoyan MiG-31M Foxhound B. It is also likely to have been intended as the main armament of the intended successor to the MiG-31M, Mikoyan's Project 701. The MiG-31M, however, has effectively been cancelled.

Vympel and MAPO MIG are looking at retrofitting the K-37 to the variants of MiG-31 now in the Russian air-defence forces inventory. The design bureau says that no approach to the defence ministry will be made until after the planned integration of the air-defence forces with the air force has taken place.

The K-37 differs from the R-33 in having an active-radar seeker, rather than a semi-active one. The K-37 is also described by Vympel as a statically unstable aerodynamic design - the R-33 was stable.

Opting for a statically unstable design required a considerably more sophisticated flight-control system, but it means that the missile is considerably more manoeuvrable than the R-33.

Source: Flight International