The Yakovlev Yak-141, alternatively referred to as the Yak-41, was an advanced Soviet fighter aircraft developed by Yakovlev.
It was specifically designed to serve as a supersonic vertical take-off/landing (VTOL) fighter, with the aim of replacing the Yak-38.
The primary objective of this aircraft was to function as a high-speed fleet defence fighter, capable of operating from Soviet carriers using short take-off and vertical landing techniques.
The project saw the construction of four prototypes, but unfortunately, it was ultimately terminated.
Yakovlev’s perspective on the Yak-38 was that it served as a temporary aircraft, primarily aimed at gaining valuable experience in the realm of military VTOL aircraft design and development.
Even prior to the introduction of the Yak-38, the Soviet Navy had expressed their desire for a more comprehensive aircraft that possessed superior capabilities compared to what the Yak-38 had to offer.
Consequently, in 1975, Yakovlev was awarded a design contract to fulfill this requirement.
The objective was to create an aircraft solely dedicated to the air defence of the fleet, with the added specification of sustained supersonic speed.
The anticipated characteristics of this aircraft included manoeuvrability, radar capabilities, and weapons loads that were on par with the current front-line fighters like the Su-27 and MiG-29.
The Soviet Navy envisioned this aircraft as their next-generation VTOL fighter, while for Yakovlev, it represented an opportunity to return to the design of Soviet fighter aircraft.
Due to the significance and intricacy of the undertaking, Alexander Sergeyevich Yakovlev allocated a substantial portion of his OKB to the advancement of the innovative VTOL fighter, known as “Product 48” or Yak-41 as designated by the military.
The project involved the simultaneous collaboration of no less than ten chief engineers, who delved into over fifty designs.
A major challenge encountered during the development process was the creation of an aircraft that possessed both vectoring thrust and an afterburner, crucial for maintaining supersonic speeds.
Initially, a twin-engine design was contemplated, but it was discarded due to the potential issue of an engine failure during landing, which would result in an immediate roll to the side.
Eventually, it was determined that the most optimal configuration would consist of a single vectoring nozzle positioned just behind the centre of gravity, along with dedicated vertical thrust jets located behind the cockpit.
A significant amount of time was dedicated to perfecting a flat, rectangular nozzle, similar to the one later employed on the American F-22 Raptor.
This type of nozzle proved to be well-suited for the necessary alterations in configuration required for both thrust vectoring and supersonic flight, while also allowing for a slender, shallow tail.
Ultimately, a circular nozzle was utilized, situated between twin booms that supported the twin-finned tail.
The components that were exposed to excessive heat from the engines during the landing phase were made from titanium, while a significant portion of the entire aircraft, at least 26%, was to be constructed using graphite or composite material.
To prevent heat build-up, the duration of hovering was limited to a maximum of 2 and a half minutes.
The arrangement of the Yak-141 powerplant involved a digital system that interconnected all three engines, enabling it to control engine start-up and adjust the thrust of all three engines during landing and hovering flight.
Additionally, twin tandem reaction control jets were located at the wingtips, and a yaw jet that could swivel was positioned beneath the nose.
The cockpit of the aircraft was designed to be both pressurized and air-conditioned, ensuring the comfort and safety of the pilot during flight.
The small canopy located at the front of the cockpit was constructed with bulletproof material, providing additional protection for the pilot.
However, due to the presence of a long dorsal spine, the canopy did not offer rear vision.
The ejection seat was equipped with an automatic arming system that was activated when the engine duct was rotated past 30 degrees and the airspeed was less than 300 km/h.
The instrumentation used in the prototypes of the aircraft was relatively simple and similar to that of the Yak-36M.
However, the production version was intended to be equipped with a wide range of advanced avionics and weapons systems, including doppler radar, laser-TV ranging and aiming, and a heads-up multifunction display (HUD).
This display was designed to work in conjunction with a helmet-mounted missile aiming system, similar to that found on the Mikoyan MiG-29.
This system allowed the pilot to lock onto an enemy aircraft by turning their head up to 80 degrees from the front.
The undercarriage of the aircraft was designed to be tricycle in configuration, with the latest multi-disc, anti-skid brakes.
The nose wheel was steerable and retracted to the rear, while the main gear retracted forward.
These features were intended to provide the pilot with greater control and manoeuvrability during take-off and landing, as well as ensuring the safety of the aircraft during ground operations.
The Yakovlev Yak-38 had a top-mounted wing that was similar to that of the Yak-36, but with a swept-back outer panel that could be folded up for storage on ships.
The main engine, the R-79V-300, was served by four side-mounted ducts and a row of large louvers along the upper surface to allow air to enter the engine during full-power hovering.
This engine was a two-shaft augmented turbofan with a bypass ratio of 1 and a maximum thrust of 14,000 kg (30,864 lb).
The rear nozzle could rotate from 0 degrees to 95 degrees for VTOL landing and hovering.
The Yak-38 also had two lift engines, the RD-41 design, which were simple single-shaft engines made mostly of titanium.
Each engine had a thrust of 4,100 kg (9,040 lb) and was installed behind the cockpit at an angle of 85 degrees.
Like the Yak-38, the engines received their air through eight spring-operated dorsal flaps, and the exhaust exited through a belly opening covered by two ventral doors.
Yakovlev successfully secured funding for the production of four prototypes.
The initial prototype, designated as 48-0 and lacking a callsign, served as a bare airframe specifically designed for static and fatigue testing purposes.
The second prototype, known as 48-1 and identified by the callsign “48,” was utilized solely as a powerplant testbed and did not have the capability to fly.
On the other hand, the third and fourth prototypes, named 48-2 and 48-3 respectively, were designated for flight testing and were assigned the callsigns “75” and “77.”
While the 48-1 prototype remained unpainted, both the 48-2 and 48-3 prototypes were painted in an overall grey colour, featuring a black radome and fin cap antennas.
The inaugural conventional flight of the Yak-141 VTOL aircraft, utilizing the 48-2 model, occurred at Zhukovsky on 9 March 1987, under the command of chief test pilot Sinitsyn.
Subsequently, on 29 December 1989, Sinitsyn executed the initial hovering flight with the 48-3 model.
Notably, he utilized the same aircraft to accomplish the first complete transition from vertical to high-speed flight and vertical landing on 13 June 1990.
Commencing from April 1991, the aircraft underwent a series of rolling take-off and run-on landings on regular runways, as well as “ski-jump” ramps at the lift jet centre in Saky.
Throughout the testing phase, the aircraft exhibited exceptional combat manoeuvres.
Chief test pilot Sinitsyn went on to establish twelve new world-class records, although these achievements were attributed to the fictitious name “Yak-141” due to the classified Yak-41 designation.
Consequently, the previously unidentified aircraft became recognized in the western hemisphere as the “Yak-141”.
In 1992, both flying aircraft were repainted in olive/grey camouflage, adorned with the Russian tricolor insignia, and marked with a white “141” in lieu of their previous call signs, “75” and “77”.
On 26 September 1991, Sinitsyn executed the initial vertical landing on the aircraft carrier Admiral Gorshkov (formerly known as Baku) using the 48-2 model.
Subsequently, an hour later, Vladimir A. Yakimov performed a vertical landing on the same deck with the 48-3 model.
The pilots continued to conduct eight flights from the carrier until Yakimov experienced a hard landing on 5 October, resulting in the rupture of a fuel tank due to damage to the undercarriage.
This incident led to a severe fire. Fortunately, Yakimov successfully ejected after approximately 30 seconds and was subsequently rescued from the sea.
The aircraft was later repaired and placed on exhibition.
In the same month, the Soviet Navy declared a lack of further funds to sustain the program.
The Smolensk factory had anticipated this situation and had refrained from constructing the necessary tooling for production.
The Soviet military initially assigned the name Yak-41M to the design.
However, as testing began and the two prototypes started setting numerous world records, it became necessary to create a different designation for use in the western countries.
This was because the name Yak-41M was classified and could not be disclosed.
Consequently, the designation Yak-141 was chosen, and it was under this name that the aircraft became recognized by western allies.
Nevertheless, within the Soviet military, the official designation for the aircraft remained Yak-41M.
In 1991, Lockheed-Martin formed a partnership with Yakovlev to further enhance the development of the aircraft, which they had always referred to as the Yak-141.
This collaboration had a significant impact, leading Yakovlev to modify the aircraft’s designation to Yak-141 for the two flyable prototypes by 1992.
It is worth noting that the series production of the aircraft in Russia could potentially result in further changes to its designation, indicating the dynamic nature of the aircraft’s development and the potential for future modifications.
In September 1991, the CIS made an announcement stating that it could no longer provide financial support for the development of the Yak-41M.
As a result, Yakovlev engaged in discussions with various foreign partners to secure funding for the program.
One of the potential partners was Lockheed Corporation, which was concurrently involved in the development of the X-35 for the US Joint Strike Fighter initiative.
Lockheed Corporation stepped forward and offered their assistance, leading to the display of aircraft 48-2 at the Farnborough Airshow in September 1992.
Yakovlev subsequently declared that they had reached an agreement with Lockheed to secure funds amounting to $385 to $400 million.
These funds were intended for the production of three new prototypes and an additional static test aircraft, which would be utilized to evaluate improvements in design and avionics.
The proposed modifications for the Yak-41M included an increase in the STOL weight to 21,500 kg (47,400 lb).
Notably, one of the prototypes was designed to serve as a dual-control trainer.
Although no longer capable of flight, both 48-2 and 48-3 were showcased at the 1993 Moscow airshow.
The partnership between Yakovlev and Lockheed commenced in late 1991, but it was not publicly disclosed by Yakovlev until September 6, 1992.
Lockheed, on the other hand, did not reveal the partnership until June 1994. Variants Yak-41 The two flying prototypes and ground test article. Yak-41M Proposed production aircraft with large leading-edge root extensions and other improvements, particularly in the avionic suite. Yak-43 A proposed development of the Yak-41M ‘Freehand’ equipped with Kuznetsov NK-321 engines. Yak-141 Designation originally applied to a single Yak-41 for disinformation and propaganda purposes when registering records with the FAI (Fédération Aéronautique Internationale) and later for promotional purposes by Yakovlev. Specifications Yak-141 Crew 1 Length 18.36 m (60 ft 3 in) Wingspan 10.105 m (33 ft 2 in) Height 5 m (16 ft 5 in) Wing area 31.7 m2 (341 sq ft) Empty weight 11,650 kg (25,684 lb) Max take-off weight 19,500 kg (42,990 lb) Powerplant 1 × Soyuz R-79V-300 afterburning vectoring-nozzle turbofan, 108 kN (24,000 lbf) thrust dry, 152 kN (34,000 lbf) with afterburner Powerplant 2 × Rybinsk (RKBM) RD-41 turbojets, 41.7 kN (9,400 lbf) thrust each canted rearwards from vertical Performance Maximum speed 1,800 km/h (1,100 mph, 970 kn) Range 2,100 km (1,300 mi, 1,100 nmi) Ferry range 3,000 km (1,900 mi, 1,600 nmi) Service ceiling 15,500 m (50,900 ft) Rate of climb 250 m/s (49,000 ft/min) Armament Guns 1 × 30 mm GSh-30-1 cannon with 120 rounds Hardpoints 4 underwing and 1 fuselage hardpoint with a capacity of 2,600 kg (5,733 lb) of external stores, with provisions to carry combinations of: Missiles R-73 Archer, R-77 Adder or R-27 Alamo air-to-air missiles Sources Yakovlev Aircraft Since 1924 – Bill Gunston & Yefim Gordon. OKB Yakovlev, A History of the Design Bureau and its Aircraft-Yefim Gordon, Dmitriy Komissarov & Sergey Komissarov. Soviet Aircrafts Illustrated-A.S.Yakovlev. The History of Soviet Aircraft from 1918-Vaclav Nemecek. Soviet AF Fighter Colours 1941-45-Erik Pilaeskii. Soviet Combat Aircraft of the Second World War, Vol 1, Single Engined Fighters-Yefim Gordon and Dmitri Khazanov. Early Soviet Jet Fighters, The1940s and early 50s-Yefim Gordon. Soviet Secret Projects, Fighters Since 1945-Tony Buttler & Yefim Gordon. Soviet Secret Projects, Bombers Since 1945-Tony Buttler & Yefim Gordon. Soviet Aircraft of Today-Nico Sgariato. Modern Soviet Fighters-Mike Spick.
