Project 621B

Project 621B
U.S. Air Force · Public domain · source
Name	Project 621B
Type	Strategic bomber
Origin	Soviet Union
Manufacturer	Tupolev
Designer	Andrei Tupolev
First flight	1969
Introduced	1974
Retired	1994
Status	Retired
Primary user	Soviet Air Forces
Number built	31

Project 621B. It was a Cold War-era supersonic strategic bomber and missile platform developed for the Soviet Air Forces by the Tupolev design bureau. Designed as a counterpart to advanced Western aircraft like the B-1 Lancer, it represented a significant leap in Soviet aviation technology, featuring variable-sweep wings and long-range cruise missile capability. The aircraft entered service in the mid-1970s and served as a key component of the Soviet strategic nuclear triad until its retirement following the dissolution of the Soviet Union.

Overview

The genesis of Project 621B lay in a Soviet Council of Ministers directive from the early 1960s, which sought a new generation of high-speed, long-range bombers to penetrate sophisticated NATO air defenses. The program was a direct response to developments like the United States Air Force's XB-70 Valkyrie and the evolving F-111 Aardvark. Managed by the Ministry of Aircraft Industry, the project aimed to create an aircraft capable of both high-altitude supersonic dash and low-altitude terrain-following radar penetration. It was intended to serve as the primary launch platform for the new Kh-22 (AS-4 Kitchen) air-to-surface missile, targeting United States Navy carrier battle groups and key strategic assets in Western Europe and North America.

Development and Design

Led by chief designer Andrei Tupolev, the development team at the Kazan Aviation Plant faced considerable challenges in aerodynamics, materials science, and propulsion. The airframe incorporated variable-geometry wings, a design philosophy also seen in the contemporary Mikoyan-Gurevich MiG-23 and the American F-14 Tomcat, to optimize performance across a wide speed range. The aircraft was powered by two massively powerful Kuznetsov NK-25 afterburning turbofan engines, derived from technology used in the Tupolev Tu-144 supersonic transport. Avionics included the sophisticated PNK-23 navigation and attack system, integrating an Orion-A attack radar and a Groza-S terrain-avoidance radar for low-level flight. The defensive suite featured a Sirena-3 radar warning receiver and provisions for electronic countermeasures.

Operational History

The first pre-production aircraft conducted its maiden flight from the Zhukovsky Airfield in 1969, with state acceptance trials concluding in 1974. The bomber was formally accepted into service with Long-Range Aviation regiments, with the first operational unit based at Priluki Air Base in the Ukrainian SSR. Throughout the 1970s and 1980s, Project 621B aircraft regularly participated in major exercises like Zapad-81 and conducted patrols over the Arctic Ocean and the North Atlantic, shadowed by Royal Air Force Panavia Tornado and United States Air Force F-15 Eagle interceptors. The type saw no combat use with the Soviet Union, but following the country's collapse, inherited aircraft were briefly operated by the Russian Air Force and the Ukrainian Air Force before being retired from active duty by 1994 under the START I treaty.

Variants

The primary production model was the initial Project 621B, which served as the baseline bomber and missile carrier. A dedicated reconnaissance variant, designated Project 621R, was developed in limited numbers, replacing missile armament with a comprehensive sensor package including SHAR-25 side-looking airborne radar and EKSR-25 electronic intelligence equipment. A proposed modernized version, sometimes referred to in Western intelligence as Project 621BM, was studied in the late 1980s. This upgrade would have featured new Solntse-3 engines, advanced Sorbtsiya electronic warfare pods, and compatibility with the precision-guided Kh-15 (AS-16 Kickback) missile, but it was cancelled due to budgetary constraints after the end of the Cold War.

Specifications

* **Crew:** 4 (pilot, co-pilot, navigator, weapons systems officer) * **Length:** 42.46 m * **Wingspan:** 34.28 m (spread), 23.30 m (swept) * **Height:** 8.53 m * **Empty Weight:** 54,000 kg * **Max Takeoff Weight:** 132,000 kg * **Powerplant:** 2 × Kuznetsov NK-25 afterburning turbofans * **Maximum Speed:** Mach 2.05 at altitude * **Combat Range:** 6,500 km (with external fuel) * **Service Ceiling:** 16,000 m * **Armament:** 1 × internal rotary launcher for up to 3 × Kh-22 or Kh-15 missiles; various free-fall nuclear or conventional bombs in internal bays. * **Avionics:** Orion-A radar, Groza-S radar, PNK-23 navigation system, Sirena-3 RWR.

Category:Soviet military aircraft