|Ship-borne Interceptor Fighter|
|High-mounted delta-winged jet|
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faces downwards. (photo, John Hayles)
The Yak-41 is a supersonic V/STOL (Vertical/Short Take-Off and Landing) naval fighter. Although it never entered operational service, some of it’s advanced technology will see application on Lockheed-Martin’s F-35 fighter.
Yakovlev’s first experiment with jet-lift was the primitive Yak-36 (NATO: Freehand), which made its first vertical take-off on 24 March 1966. Vertical take-off on this aircraft was achieved by locating a swivelling jet exhaust nozzle for each of it’s two engines directly under the aircraft’s centre of gravity. The experience thus gained led to the larger Yak-38 naval fighter-bomber (NATO: Forger), which first flew in 1970 and entered service with the AV-MF (Fleet Naval Aviation) on 6 October 1976. This time, twin swivelling exhaust nozzles for the single main engine were combined with two dedicated lift engines located in the forward fuselage. Unfortunately, the technology incorporated in the Yak-38 was still immature and the type encountered numerous technical and operational problems.
Lack of thrust from the Yak-38’s engines severely limited the possible weapons payload and the amount of fuel that could be carried, whilst high fuel consumption resulted in very poor range. No radar was carried, to save weight, which limited it’s ability to carry out air defence missions. In addition, aircraft serviceability remained low throughout the type’s service life.
While development work on the Yak-38 was still proceeding, Yakovlev was authorised in 1975 to begin work on a more capable replacement, for use in the fleet air defence role from AV-MF aircraft carriers. After exploring a number of enhancements to the Yak-38 airframe it was concluded that only a much larger airframe with more powerful engines could hope to provide the neccessary performance. Designated Yak-41, the resulting new design retained the same basic layout as the Yak-38 but was almost 30% larger and twice as heavy (in empty weight) as its predecessor. A Fazotron S-41M Zhuk radar was installed in the nose.
To power the Yak-41, a new engine was developed. The R-79 was fitted with an afterburner to allow supersonic performance, while the single swivelling exhaust nozzle was located between two deep tail booms. Two new RD-41 lift engines were installed behind the cockpit, inclined forwards by 5 degrees and exhausting through nozzles which could deflect by +/- 12.5 degrees to give thrust vectoring. During a vertical take-off or landing the main nozzle pointed 90 degrees downwards, while for a short take-off it was deflected at 63 degrees.
In 1977 the decision was made to proceed with full development of the Yak-41, and in the following year construction began of the aircraft carrier Baku (later renamed Admiral Gorshkov), which was expected to include the Yak-41 in it’s air wing.
In 1985 it was decided to make the Yak-41 a multi-purpose fighter rather than a dedicated interceptor, under the designation Yak-41M. The design of the additional aircraft systems required caused a delay in the development programme. Two static test Yak-41Ms were build – the first (48-0) was used for static and fatigue tests, while the second (48-1, bort ’48’ yellow) was employed performing engine ground running trials in both cruise and VTOL modes. These two airframes were followed by two flight-rated airframes ’75’ white (48-2) and ’77’ white (48-3).
The first flight was made on 9 March 1987 in conventional mode, and the first hover was carried out on 29 December 1989. During April 1991 a series of flights gained 12 FAI recognised world records for VTOL aircraft, which were recorded under the designation Yak-141. This designation was later re-used for the proposed export variant of the aircraft.
On 26 September 1991 the first landing on board Admiral Gorshkov was successfully accomplished. Unfortunately, on 5 October 1991, aircraft ’77’ white experienced a landing accident aboard the carrier which resulted in it being grounded. Economic reality caught up with the Yak-41M in November 1991 when a drastically reduced defence budget for the newly created CIS left the programme without any further state funds.
In September 1992 aircraft ’75’ white was repainted as ‘141’ white and displayed at the Farnborough Air Show, in an attempt to attract foreign funding, but this ploy was unsuccessful and development ceased in 1993.
The production version was planned to feature uprated engines allowing take-off with more weapons or additional fuel. A prototype two-seat trainer was never completed. An advanced stealthy version designated Yak-43 remained only a project.
During the summer of 1995, Lockheed Martin announced a teaming arrangement with Yakovlev to assist in the former’s bid for the JAST (Joint Adanced Strike Technology) competition. Yakovlev’s knowledge of jet lift technology was to prove invaluable. Lockheed Martin was subsequently selected to build a demonstrator aircraft, the X-35, which went on to win the JSF (Joint Strike Fighter) competition and will soon become a production fighter as the F-35.
One of the key problems with the Yak-41M jet-lift system was the need to engage afterburner for vertical take-off or landing. At land bases this soon resulted in damage to the runway, while the Admiral Gorshkov was fitted with a special water-cooling system to absorb the heat from the jet blast. Hence, the Yak-41M was in no sense a Harrier-style go-anywhere aircraft.
Requirement Specification: –
Manufacturers Designation: Izdelye 48, Izdelye 48M
|‘Ram-T’||Interim designation assigned by NATO to Yak-41M.|
|Yak-41||Various alternative configurations explored, including: single lift/cruise engine with single vectoring nozzle, lift engines ahead of cockpit, directable rectangular afterburner exhaust or Yak-45 variant.|
|Yak-41||Original dedicated interceptor design. [Izdelye 48]|
|Yak-41M||Planned production version with added anti-ship capability. 2 flying prototypes built. Production aircraft would have had uprated R-79M engines and flight refuelling probe. [Izdelye 48M]|
|Yak-41U||Tandem two-seat trainer version – prototype not completed.|
|Yak-43||Projected advanced STOL version – land based for VVS use. Samara NK-321 engine from Tu-160 bomber + 2 RD-41 lift engines. Trapezoidal wing, lengthened fuselage with increased fuel load and internal weapons bay. Reduced radar signature. [Izdelye 201]|
|Yak-141||Designation applied to Yak-41M for record breaking flights. Later used as export designation for Yak-41M.|
|Yak-141M||Designation for proposed export variant of Yak-41M. Increased STO weight to 21,500 kg (47,399 lb). Improved avionics.|
|The side view emphasises the length of the
Yak-141. (Photo, John Hayles)
|Twin-boom tail with main nozzle in-between.
(Photo, John Hayles)
|1975||Government directive to start work on Yak-38 replacement.|
|1977||Detailed design of the Yak-41 begins.|
|1985||Decision in favour of Yak-41M multi-purpose variant.|
|1986||Second ground test airframe (bort 48 yellow) begins engine runs.|
|1986||Programme first noticed by the West at Zhukhovskii. Temporarily named ‘Ram-T’.|
|9 March 1987||Yak-41M first flight from rolling take-off (bort 75 white).|
|Spring 1988||NATO reporting name ‘Freestyle’ assigned.|
|12 April 1989||Second prototype (bort 77 white) makes first flight from rolling take-off.|
|Summer 1989||Mach 1 exceeded for the first time.|
|29 December 1989||First hovering flight (bort 77 white).|
|13 June 1990||First full profile flight (VTO – cruise – VL).|
|April 1991||Andrei Sintsyn sets 12 world records for VTOL aircraft as ‘Yak-141’.|
|26 September 1991||First landing aboard aircraft carrier Admiral Gorshkov.|
|5 October 1991||Aircraft 77 white damaged in hard landing on Admiral Gorshkov.|
|November 1991||Russian government funding support ceases.|
|September 1992||‘Yak-141’ appears at Farnborough Air Show in UK.|
|1993||Planned delivery date for first production aircraft – cancelled.|
|1993||Work on Yak-41 terminated.|
|Summer 1995||Programme temporarily revived under Lockheed-Martin contract.|
|Russia – Naval Air Force (AV-MF)||(Yak-141)|
|Sharp-edged supersonic air intakes and
radar nose. (Photo, John Hayles)
|The lift fan doors are still open in this underside
view. (Photo, John Hayles)
|Yakovlev Yak-41 ‘Freestyle’|
|Crew: 1 pilot|
|Dimensions: Length 60 ft 0 ins (18.30 m); Height 16 ft 5 in (5.00 m); Wing Span 33 ft 1.75 in (10.10 m), 19 ft 4.25 in (5.90 m) wings folded; Wing Area 341.56 ft2 (31.7 m2)|
|Engines: One Soyuz/Kobchenko R-79V-300 vectored-thrust lift/cruise turbofan developing 34,170 lb (15,500 kg) with afterburning or 23,148.5 lb (10,500 kg) dry, plus two Rybinsk/Kuznetsov RD-41 turbofan lift engines each rated at a 9,039lb (4,100kg) dry|
|Weights: Empty equipped 25,684 lb (11,650 kg); VTO max take-off 34,833 lb (15,800 kg); STO max take-off 42,990 lb (19,500 kg)|
|Armament:One 30 mm Gsh-30-1 cannon under the port side fuselage with 120 rounds, four underwing hardpoints (all inboard of the wing fold) rated at (1102 lb) 500 kg each for R-77/AA-12 ‘Adder’ or R-27/AA-10 ‘Alamo’ radar-guided medium-range missiles and R-73/AA-11 ‘Archer’ short-range IR-guided missiles, or Kh-31A (AS-17 Krypton) and Kh-35 anti-shipping missiles, or Kh-31P and Kh-58 (AS-11 Kilter) anti-radar missiles, bombs or unguided rockets and one under-fuselage hardpoint for a conformal fuel tank. VTO max external load 2,204 lb (1,000 kg), STO max external load 5,732 lb (2,600 kg), max external fuel 2000 litres (440 Imp Gal) or 3,858 lb (1,750 kg).|
|Performance: Maximum level speed 675 kts (777 mph, 1,250 km/hr) at sea level, 971 kts (1118 mph, 1,800 km/hr) at 36,089 ft (11,000 m), Mach 1.8 maximum; Initial rate of climb 49,213 ft/min (250 m/sec); Service ceiling more than 49,215 ft (15,000 m); VTO clean range at sea level (no external weapons) 351 nm (404 miles, 650 km), with 4,409 lb (2,000 kg) weapon load and take-off run of 394 ft (120 m) 372 nm (690 km), VTO clean range at 32,808-39,370 ft (10-12,000 m) 755 nm (870 miles, 1,400 km), max range with external fuel and short take-off 1,133 nm (2,100 km), range with vertical takeoff and internal fuel 755 nm (1,400 km).|
|Note the open intake blow-in doors during
take-off. (Photo, John Hayles)
|The Farnborough display started with a
rolling take-off. (Photo, John Hayles)
Head of Design Team: S.G. Mordovin & A.B. Zvyagintsev, later Konstantin Popovich
Design Office: A.S. Yakovlev OKB, 68 Leningradsky Prospeckt, 125315 Moscow
|Version||Quantity||Assembly Location||Time Period|
|Yak-41||4||Yak OKB, Moscow||1985-1989|
Total Produced: 4 a/c (1 structural article + 1 ground test article + 2 flight test examples)
[Small Yak-41M production batch ordered early 1991 from Smolensk factory, but cancelled November 1991]
To be added.
‘SOVIET V/STOL AIRCRAFT: Struggle for a Shipborne Combat Capability’ [Order this book from Amazon UK]
by Michael J. Hirschberg
Published by AIAA, USA, June 1997 ISBN: 1563472481
* Technical study of the Yak-36, Yak-38 and Yak-41.
‘Yakovlev’s V/STOL Fighters – Yak-36, Yak-38, Yak-41 and Yak-141 (Aerofax series)’ [Order this book from Amazon UK]
by John Fricker and Piotr Butowski
Published by Midland Publishing Ltd, UK, Nov 1995 ISBN: 1 85780 041 9
* Well illustrated profile of the three V/STOL types.
‘Brassey’s World Aircraft & Systems Directory 1996/97’ [Order this book from Amazon UK]
by Micheal Taylor
Published by Brassey’s (UK) Ltd, 1996 ISBN: 1 85753 198 1
* Includes a detailed description of the Yak-41.
‘Yakovlev Aircraft since 1924’ [Order this book from Amazon UK]
by Bill Gunston & Yefim Gordon
Published by Putnam Aeronautical Books, 1997 ISBN: 1 85177 872 0
* Includes a short chapter on the Yak-41.
‘International Air Power Review, Volume 10’ [Order this book from Amazon UK]
Published by AIRtime Publishing, 2003 ISBN: 1 880588 58 7
* Includes feature article on the Yak-36, Yak-38 and Yak-41.
‘Aviamaster’ N7 2003
* Russian text feature article.
(Specification, description and some close-up photos)
(Well illustrated French-text description of the Yak-41)
(Short description, specification and 2 photos)
(Short description, specification, 3-view)
(9 Yak-41 photos)
(Yakovlev design bureau official description and small photos)
(Building Yak-41 scale model + 14 close-up photos of actual aircraft)
(15 Yak-41 photos)
Soviet Jet VTOL
(Well-written profile of the Yak-36, Yak-38 & Yak-41)
(Description, specification, 2 photos)
Flight Simulator Models:
To be added.
To be added.
See the ‘Aviamaster’ magazine listed above.