The Bisnovat (later Molniya) R-4 (NATO reporting name AA-5 'Ash') was an early Soviet long-range air-to-air missile. It was used primarily as the sole weapon of the Tupolev Tu-128 interceptor, matching its RP-S Smerch ('Tornado') radar.

Development of the R-4 began in 1959, initially designated as K-80 or R-80, entering operational service around 1963, together with Tu-128.^[1] Like many Soviet weapons, it was made in both semi-active radar homing (R-4R) and infrared-homing (R-4T) versions.^[2] Standard Soviet doctrine was to fire the weapons in SARH/IR pairs to increase the odds of a hit.^[3] Target altitude was from 8 to 21 km. Importantly for the slow-climbing Tu-128, the missile could be fired even from 8 km below the target.

In 1973 the weapon was modernized to R-4MR (SARH) / MT (IR) standard, with lower minimal target altitude (0.5–1 km),^[4] improved seeker performance, and compatibility with the upgraded RP-SM Smerch-M radar.

The R-4 survived in limited service until 1990, retiring along with the last Tu-128 aircraft.^[1]

 Soviet Union

• Soviet Air Defence Forces

• Length: (R-4T) 5.2 m (17 ft 1 in); (R-4R) 5.45 m (17 ft 10 in)
• Wingspan: 1300 mm (4 ft 3 in)
• Diameter: 310 mm (12.2 in)
• Launch weight: (R-4T) 480 kg (1,058 lb); (R-4R) 492.5 kg (1,086 lb)
• Speed: Mach 1.6
• Range: (R-4T) 2–15 km (9.35 mi); (R-4R) 2–25 km
• Guidance: (R-4T) infrared homing; (R-4R) semi-active radar homing
• Warhead: 53 kg ( 116.6 lb) high explosive

• Gordon, Yefim (2004). Soviet/Russian Aircraft Weapons Since World War Two. Hinckley, England: Midland Publishing. ISBN 1-85780-188-1.
• Gunston, Bill (2000). The Osprey Encyclopedia of Russian Aircraft. Oxford: Osprey. ISBN 978-1-84176-096-4.

• К-80, Р-4 - description in Russian, with pictures.