Yakovlev Yak-25

Yakovlev

Industry	Aerospace
Founded	1934
Headquarters	Moscow , Soviet Union

For the initial prototype jet fighter, see Yakovlev Yak-25 (1947).

The Yakovlev Yak-25 (known by NATO as Flashlight-A or Mandrake) is a twin-engine, swept-wing interceptor and reconnaissance jet developed by Yakovlev for use by the Soviet Union.

Design and development

The Yak-25 was conceived to fulfill the requirement for a long-range interceptor capable of defending the USSR’s northern and eastern frontiers. On 6 August 1951, Joseph Stalin issued a directive calling for a two-seat, twin-engine jet fighter along with a related reconnaissance variant.

Yak-120

In response, Yakovlev initiated development of a twin-engine, two-seat patrol interceptor designated as the Yak-120 in 1951. The project received official approval from the Council of Ministers of the Soviet Union on 10 August that year. Departing from previous Yakovlev designs, the Yak-120 featured thin mid-mounted wings swept back at a 45-degree angle, equipped with large two-section flaps. To enhance directional stability, a ventral fin was installed beneath the cruciform tail assembly. The powerplant consisted of two Mikulin AM-5 turbojet engines housed in nacelles mounted directly under the wings.

To maximize fuel storage for extended endurance, the aircraft utilized a bicycle-style landing gear arrangement with a single-wheel nose gear and dual-wheel main gear, complemented by outrigger wheels under each wingtip. Additionally, it could carry a conformal drop tank centrally beneath the fuselage to further increase range.

Equipped with an RP-6 Sokol radar housed within a bullet-shaped glass fiber radome at the nose, the system could detect four-engine bombers up to 25 km away and fighter aircraft at distances of approximately 16 km. The cockpit accommodated two crew members seated in tandem beneath a shared canopy that slid rearwards. The radar operator was responsible for target acquisition and assisting the pilot during adverse weather conditions; dual flight controls enabled this crew member to pilot the aircraft when necessary, reducing pilot fatigue on extended missions. The windshield incorporated a bullet-resistant glass panel measuring 105 millimetres (4.1 in), while the fuselage was protected by 10 millimetres (0.39 in) armor plating throughout.

Armament comprised two low-mounted 37 mm NL-37L cannons on either side of the fuselage centerline, each supplied with a standard load of 50 rounds, though ammunition boxes could hold up to twice that amount. Underwing pylons allowed carriage of two 212 millimetres (8.3 in) unguided ARS-212 rockets. The onboard avionics suite enabled navigation and interception capabilities under all weather conditions up to its operational ceiling. In addition to radar, systems included an SRO-1 IFF transponder, an RSIU-3 Klyon VHF radio, and an AP-28 autopilot. For automatic landing approaches in poor visibility, it was fitted with a Materik (meaning "continent") instrument landing system. The Pozitron-1 system rounded out its avionics package and was likely intended as a command link system.

Hot air de-icing was applied to wings, tail surfaces, and engine intakes, while electrical heating protected the engine intake centerbodies and foreign object damage screens. These features allowed prolonged operation at high altitudes in cold climates. Despite its sophisticated and heavy electronic systems, structural weight was minimized through efficient design techniques, resulting in a relatively lightweight airframe for a twin-engine fighter. Yakovlev produced two prototypes along with a static test model; the first prototype conducted its maiden flight on 19 June 1952 under test pilot Valentin Volkov’s control. Manufacturer testing proceeded until November of that year.

The Yak-120 met or exceeded all Air Force operational requirements except for speed and range. It demonstrated an endurance of three hours and forty-five minutes without external tanks (extending to four hours and fifteen minutes with drop tanks) and had an internal fuel range of approximately 2,800 km at an altitude of 12,000 meters—capabilities suitable for long-range patrol missions. Being smaller and lighter than its competitor, the Lavochkin La-200B, it offered superior performance. However, delays in RP-6 radar development prevented it from entering state acceptance trials initially; consequently, an interim RP-1 Izumrood radar was installed in early December for testing purposes. Between May and June 1953, trials conducted at the Scientific Research Institute of the Air Force (NII VVS) with this radar yielded mostly favorable outcomes, leading to authorization for production under the designation Yak-25. The NII VVS test results were formally adopted as specifications for the Yak-25 by Council of Ministers decree on 8 September.

Production and Yak-25M

Manufacture of the Yak-25 took place at Factory No. 292 located in Saratov, with the initial unit completed in September 1954. The radar system installed on these aircraft was designated RP-1D due to minor alterations. Nevertheless, only a limited number of units adhered to the original configuration because the RP-6 radar had been fully developed by late 1953. In April 1954, a Yak-120 prototype equipped with the RP-6 successfully passed state acceptance testing, and on 13 May, the Council of Ministers authorized production of an updated model named the Yak-25M. This variant featured several enhancements beyond the radar upgrade: the original AM-5A Series 1 turbojets were replaced by RD-5A (AM-5A) Series 2 engines maintaining equivalent power output; the nose landing gear was moved forward by 33 cm to enhance directional stability during takeoff and landing; and muzzle brakes were added to the cannons. The Saratov facility produced 406 Yak-25Ms, with deliveries commencing in January 1955. Beginning in October 1956, RAF RPF ELINT missions confirmed the Yak-25M's operational deployment but noted that ground-based radar height-finding capabilities were inadequate, limiting interception effectiveness above 35,000 feet.

Further Yak-120 development

Following completion of the first phase of state acceptance trials for the Yak-120 in September 1953, the second prototype was re-equipped with the Mikulin AM-9A turbojet, an enhanced iteration of the AM-5 engine. Additionally, rocket pods carrying 57-millimeter (2.2 in) ARS-57 Skvorets folding-fin rockets were installed, intended to engage enemy bomber formations. Plans included fitting a modified RP-6 radar known as Sokol-M, with this configuration designated as the Yak-120M scheduled to begin state trials in September 1954. However, delays caused by late engine deliveries and radar unavailability postponed completion until year-end 1954, resulting in installation of a standard RP-6 instead. The initial stage of state acceptance testing (without FFARs and using the standard RP-6) was deferred from November to January 1955. By March, preparations were underway for a second stage featuring Sokol-M radar and FFARs. The directive adjusting this timeline also mandated inclusion of 190-millimeter (7.5 in) TRS-190 rockets as alternative armament. To compensate for increased ordnance weight, lighter 23-millimeter (0.91 in) Nudelman-Rikhter NR-23 cannons replaced the heavier N-37Ls.

The first stage of Yak-120M state acceptance trials concluded on schedule in January 1955; the second stage commenced in March and finished by late April. Despite this, performance fell marginally short of operational criteria, and failure to finalize Sokol-M integration combined with emerging requirements for supersonic interceptors led to discontinuation of the Yak-120M program. Subsequently, the prototype was repurposed as a test platform for RD-9F engines under the designation Yak-120MF.

During 1955 and 1956, multiple Yak-25Ms were converted into testbeds for air-to-air missile systems.

Yak-125, Yak-25R, and Yak-25MR

File:Yakovlev Yak-25R and Yak-125B side-view silhouettes.png

Yakovlev Yak-25R and Yak-125B

The Yak-125 was developed as a two-seat tactical reconnaissance aircraft prototype alongside the Yak-120. To accommodate two AKAFU automatic tilting camera mounts placed side by side, the radar system was removed and the nose was slightly elongated. These mounts supported vertical photographic cameras such as the AFA-33/100M, AFA-33/75M, or AFA-33/50M. Additionally, a flexible oblique camera mount equipped with either an AFA-33/75M or AFA-22/50M camera was installed forward to provide coverage of the port and starboard sides. Hinged doors protected the camera ports during takeoff and landing, with the reconnaissance systems operator in the rear cockpit managing both the ports and cameras. Instead of the twin cannons found on the Yak-120, the Yak-125 featured a single NR-23 cannon with 80 rounds mounted on the starboard fuselage. The internal fuel capacity was enhanced to 3,925 litres (863 imp gal).

Completed in August 1952, the prototype conducted its maiden flight on 26 August under pilot Volkov. Manufacturer flight tests were concluded by October 1953, followed by state acceptance trials from December 1953 to February 1954. The Yak-125 demonstrated superior performance compared to the production Ilyushin Il-28R and Mikoyan-Gurevich MiG-15bisR reconnaissance variants. However, due to visibility challenges for both the pilot—caused by the extended nose—and the reconnaissance operator, who had limited view through a small ventral window, the state commission recommended modifications and authorized a limited pre-production run for service evaluation.

In response to these recommendations, the Yak-125’s forward fuselage underwent redesign. The reconnaissance systems operator was relocated to a dedicated compartment in the nose, where oblique and vertical cameras were mounted directly ahead of the seat. Additional cameras were positioned along the central fuselage, while other aspects of the aircraft remained consistent with the original Yak-125 design. This revised version was designated as the Yak-25R. Following a Council of Ministers directive dated 10 March 1955 and an order from the Ministry of Aircraft Production issued on 11 March, Yakovlev and Factory No. 292 in Saratov were assigned to produce ten pre-production units. Despite this, production did not proceed due to obsolescence concerns, Yakovlev’s development of a more advanced supersonic reconnaissance aircraft nearing readiness for testing, and the selection of the Il-28R as the principal reconnaissance platform for Soviet Air Forces.

Pursuant to a Council of Ministers directive from 18 September 1954 and a subsequent Ministry of Aircraft Production order three days later, Yakovlev was commissioned to develop a high-speed maritime reconnaissance variant of the Yak-25, known as the Yak-25MR. This model aimed to fulfill Soviet Naval Aviation’s requirements for maritime reconnaissance capabilities while matching or surpassing existing Yak-25 performance levels. State acceptance trials for this version commenced in February 1955.

Yak-125B

Under a special joint directive issued by the Central Committee of the Communist Party and the Council of Ministers, Yakovlev was assigned to create a high-velocity nuclear bomber based on the Yak-125 platform, designated as the Yak-125B. This aircraft was designed to penetrate hostile air defenses and execute nuclear strikes on strategic targets deep within enemy territory. The crew consisted of two members, with the navigator also serving as the bombardier, positioned in a compartment at the very front of the aircraft. The nuclear weapon was stored in a bomb bay located near the plane’s center of gravity, which necessitated that the nose landing gear be equipped with twin wheels similar in size to those on the main landing gear, which had been relocated just behind the bomb bay. This landing gear configuration was subsequently adopted for Yakovlev tactical bombers, such as the Yak-28. The Yak-125B was notable for being the first Yakovlev design to incorporate a 360-degree ground mapping and bombing radar system, known as the RMM-2 Rubidiy, housed within a radome situated beneath the cockpit. Flight trials commenced in 1955, with plans to designate the production model as the Yak-25B. Nevertheless, it never reached production status due to its obsolescence and because Yakovlev was concurrently testing a more advanced supersonic nuclear bomber, the Yak-26.

File:Yakovlev Yak-25RV three-view silhouette.png

Yak-25RV

Yak-25RV

The Yak-25RV (Razvedchick Vysotnyj, meaning "high-altitude reconnaissance") emerged in 1959 as a reconnaissance variant of the Yak-25, receiving the NATO codename 'Mandrake.' It featured an entirely redesigned long-span straight wing measuring 23.4 meters—more than double that of the Yak-25M interceptor—with a total wing area of 55 square meters. The fuselage was modified to accommodate camera and sensor equipment packages. Some models may have retained a single cannon for defense.

File:Yakovlev Yak-25RRV front-view silhouette.png

Yak-25RRV

Although benefiting from low wing loading, the 'Mandrake' delivered only modest altitude performance, plagued by significant engine issues at high elevations, pronounced vibration problems, and rudimentary onboard systems that placed heavy demands on flight crews. Despite these limitations, the Soviet Air Force operated the Yak-25RV until 1974. During the late 1970s, several units were repurposed for radioactive contamination surveillance equipped with specialized sensors and redesignated as Yak-25RRV. Attempts in 1971 to convert the 'Mandrake' into a high-altitude interceptor variant (Yak-25PA) did not succeed.

File:Yakovlev Yak-26-3, Yak-27P and Yak-27V side-view silhouettes (cropped).png

Yakovlev Yak-26

In 1961, a series of lightened 'Mandrake' models were produced to serve as high-altitude target drones. The manned version, Yak-25RV-I, was employed for interception training without live armament, while the remotely controlled Yak-25RV-II functioned as an unmanned drone.

Yak-26

The Yak-26 was developed as a bomber variant derived from this family; however, only nine units were ever constructed.

Operational history

The Yak-25 made its debut at Tushino Airfield in July 1955 and was initially assigned the NATO reporting name Flashlight. This designation was later modified to Flashlight-A following the identification of the Yak-26 and Yak-27. Beginning in 1955, it was introduced into air defense units. The aircraft was well-regarded for its ease of handling and was favored by its pilots. However, engine failures occurred frequently, mainly because the engines were positioned low when the aircraft was on the ground, necessitating well-maintained airstrips. Despite this, the twin-engine setup ensured that most malfunctions did not result in catastrophic outcomes.

Pilots appreciated the enhanced reliability provided by the dual engines and the presence of a radar intercept operator, especially during extended missions over the remote northern and eastern regions of the Soviet Union.

In 1955, a total of 108 pilots along with 95 ground personnel completed their conversion training on the Yak-25M at the Savasleyka PVO Training and Methodical Center. Designed primarily for low-altitude operations, the Yak-25's maximum operational ceiling was insufficient to intercept American RB-47 Stratojet reconnaissance flights that frequently penetrated Soviet airspace.

The phase-out of Yak-25 models commenced in 1963. By 1967, all Yak-25 interceptors had been retired; however, the 'Mandrake' reconnaissance variant remained active in various capacities until the late 1970s. Consistent with many other PVO interceptors from the Cold War period, the Yak-25M was never exported to Warsaw Pact allies or other countries.

Variants

Yak-25

The initial production model fitted with RP-1D "Izumrud" radar. A total of 67 units were manufactured.

Yak-25B

A planned production variant derived from the Yak-125 tactical nuclear bomber prototype.

Yak-25M

The primary production model featuring minor enhancements, upgraded AM-5A engines, and a new RP-6 "Sokol" radar system. Produced in a quantity of 406 aircraft.

Yak-25MG

A number of Yak-25M units were modified with the 'Gorizont-1' system enabling autopilot control from ground stations for ground control interception operations. Aviation historian Yefim Gordon notes that this designation also applied to Yak-25Ms later upgraded with the Granat radar system.

Yak-25RV NATO reporting name Mandrake

(Razvedchick Vysotnyj, meaning "high-altitude reconnaissance") A high-altitude reconnaissance variant equipped with redesigned wings and fuselage-mounted camera and sensor arrays. A total of 155 were built.

Yak-25RR

(Radiatsionyy Razvedchik - radiation reconnaissance) This variant of the Yak-25RV carried specialized instrumentation for detecting radioactive contamination.

Yak-25RRV

(Rahdiotekhnicheskiy Razvedchik Vysotnyy - high altitude electronic intelligence) A Yak-25RV outfitted with dedicated SIGINT equipment.

Yak-25RV-I

A version used as a manned target aircraft for interception training without live ammunition.

Yak-25RV-II

A remotely piloted drone designed for live-fire interception exercises.

Yak-25PA

(perekhvahtchik aerostahtov - balloon interceptor) A balloon interception variant based on the Yak-25RV, likely armed with a single cannon; only one unit was built or converted.

Yak-25 series prototypes and experimental models

Yak-2AM-11

Projects for reconnaissance and tactical reconnaissance utilizing two Mikulin AM-11 (Tumansky R-11) engines; these plans were discontinued as Tumansky R-11 production was prioritized for the MiG-21.

Yak-13

Direct predecessor to the Yak-120, this model was never constructed. The designation was previously assigned to a 1946 light touring aircraft.

Yak-25K

A variant of the Yak-25M with the cannon removed, outfitted with the Yak-25K-5 weapons system, which included the "Izumrud" radar and four RS-1U (NATO reporting name AA-1 "Alkali") beam-riding missiles mounted on the wings between the engines and fuselage. A limited quantity was produced.

Yak-25K-7L

A Yak-25K modified as a test platform for K-7L missiles. This configuration did not enter operational service, and further development of the aircraft was halted.

Yak-25K-75

A testbed based on the Yak-25M designed for trials with K-75 missiles. Neither the weapon nor this aircraft variant reached service entry.

Yak-25K-8 (also known as Yak-25S K-8)

Two Yak-25K aircraft were adapted to test the Yakovlev K-8 missile system, each carrying two K-8 (NATO codename AA-3 'Anab') missiles. Additionally, two Yak-25M airframes (designated Yak-25S K-8) underwent modifications for missile carriage trials. The program was discontinued in favor of the emerging Yak-28P.

Yak-25L (letayuschchaya laboritoriya – flying laboratory)

Served as a platform for evaluating ejection seat systems.

Yak-25MR (morskoy razvedchik – maritime reconnaissance)

A prototype developed specifically for maritime reconnaissance missions.

Yak-25MSh

Developed as a radio-controlled target drone prototype. Although not produced in this designation, numerous existing aircraft were later converted into drones during their service life.

Yak-25R

A reconnaissance variant featuring a glazed nose section to accommodate a second crew member (navigator) and equipped with two cameras. It retained armament consisting of a 23mm cannon. Ten pre-production units were manufactured.

Yak-26

A tactical nuclear bomber derivative with nine examples built.

Yak-120M

An upgraded version of the Yak-120 powered by Mikulin AM-9A engines (an AM-5 variant with an added compressor stage, can-annular combustion chamber, afterburner, and enhanced avionics and weaponry).

Yak-120MF

A conversion of the Yak-120M serving as a test platform for RD-9F engines.

Yak-122

A tactical reconnaissance prototype evolving from both the Yak-25 and Yak2AM-11 projects, powered by two RD-9F turbojets. This aircraft was later modified into the Yak-27R tactical reconnaissance prototype.

Yak-123

Prototype developed for the Yak-26 tactical nuclear bomber program.

Yak-125B

The OKB designation assigned to the Yak-25B tactical nuclear strike prototype, capable of carrying one special external pod (spets podveska).

Yak-SM-6

Two production Yak-25s adapted to test K-6 air-to-air missiles. Although the missile program was cancelled, these aircraft were repurposed for other testing roles.

Operators

Template:USSR

• Soviet Air Force
• Soviet Anti-Air Defense

Specifications (Yak-25)

File:Jak 25.svg

Yakovlev Yak-25 three-view schematic

External links

• Yak-25 at Ugolok Neba – Russian-language resource featuring descriptions, images, and schematics