Sukhoi S-37
"Sukhoi S-37
Country of origin: Russia
Type: Fighter technology demonstrator
Powerplants: Two 152kN (34,200lb) with afterburning Aviadvigatel D-30F6 turbofans. May latter
be fitted with two 196kN (44,000lb) with afterburning and thrust vectoring Saturn AL-31 F
turbofans.
Performance: Max speed at 30,000ft 2200km/h (11 190kt), max speed at sea level 1400km/h (756km/h). Service ceiling
59,000ft. Basic range 3300krn (1 782nm).
Weights: Normal takeoff 25,670kg (56,590lb), max takeoff 34,000kg (74,690lb).
Dimensions: Wing span 16.7m (54.7ft), length 22.6m (74ft), height 6.4m (21 ft).
Accommodation: Pilot only
Armament: None in the prototype. A production version would carry air-to-air and air-to-ground weapons in internal
weapons bays and on external pylons.
Operators: Experimental aircraft, not in operational service.
History: The S-37 is an experimental fighter technology demonstrator built to validate and gain experience with various
technology advances (particularly the forward swept wings) which could be incorporated into a fifth generation Sukhoi
fighter.
.
The S-37 was initially known as the S-32 and initial reports of the program's existence surfaced in early 1996 when it
appeared the aircraft was intended to be a fifth generation fighter, rather than a technology demonstrator.
The S-32 first flew on September 25 1997 (two weeks after the F-22's first flight), with greater details and photographs
made public shortly after. The most obvious feature of the new Sukhoi is its forward swept wing, which is made of
composite materials to give the necessary structural strength. Benefits of forward sweep include improved maneuverability
at subsonic speeds, enhanced controllability at high angles of attack, reduced takeoff and landing rolls (also resulting in
improved range) and a reduced forward hemisphere radar signature (the S-37 may also be fitted with radar absorbent
material).
As well as the forward swept wings, the S-37s flying and control surfaces include canards, conventional horizontal tails and
slightly outward canted twin vertical tails.
Power for the S-37 is provided by twin Aviadvigatel D-30F6 turbofans, generating 152kN (34,200lb) with afterburner (the D-
30FR also powers the MiG-31). Later on the S-37 may be fitted with 196kN (44,000lb) Saturn AL-41F turbofans. The S-
37's inlet are fixed, while air scoops on the wings' leading edge extend to provide the engines with additional airflow at low
speeds.
The S-37's canopy and cockpit are from the Su-27, the landing gear from the Su-27K.
Sukhoi hopes to develop the S-37 into an operational fighter for the Russian air force, but significant obstacles would have
to overcome for this to become reality, including funding difficulties and MiG MAPO's rival 1-42."
(source: International Directory of Military Aircraft 1998-1999)
A COMPARISON OF S-37, SU-30M, SU-32FN AND X-29 TECHNICAL CHARACTERISTICS
S-37 Su-30M Su-32FN X-29
DIMENSIONS: DIMENSIONS: DIMENSIONS: DIMENSIONS:
Wingspan (m) 16.7 Wingspan (m) 14.7 Wingspan (m) 14.7 Wingspan (m) 8.3
Overall length (m) 22.6 Overall length (m) 21.9 Overall length (m) 25.2 Overall length (m) 14.7
Overall height (m) 6.4 Overall height (m) 6.4 Overall height (m) 6.2 Overall height (m) 4.4
WEIGHTS: WEIGHTS: WEIGHTS: WEIGHTS:
Empty weight (kg) 24,000 Empty weight (kg) 17,700 Empty weight (kg) 29,060 Empty weight (kg) 6,045
Normal take-off weight (kg) 25,669 Normal take-off weight (kg) 24,500 Normal take-off weight (kg) 42,000 Normal take-off weight (kg) 7,849
Maximum take-off weight (kg) Maximum take-off weight (kg) Maximum take-off weight (kg) Maximum take-off weight (kg) -
34,000 33,000 44,360
PERFORMANCE (estimated): PERFORMANCE (estimated): PERFORMANCE (estimated): PERFORMANCE (estimated):
Number of engines and type (2) D- Number of engines and type (2) AL- Number of engines and type (2) AL- Number of engines and type (2)
30F6M (2) 31F 35F F404-GE-400
Thrust (kgf / lbf) 15,500/34,200 Thrust (kgf / lbf) 12,490/27,557 Thrust (kgf / lbf) 13,990/30,865 Thrust (kgf / lbf) 7,252/16,000
Maximum level speed: At altitude Maximum level speed: At altitude Maximum level speed: At altitude Maximum level speed: At altitude
(km/h) 2,500; at sea-level (km/h) (km/h) 2,500; at sea-level (km/h) (km/h) 2,500; at sea-level (km/h) (km/h) -; at sea-level (km/h) -
1,400 1,345 1,400 Service ceiling (m / ft)
Service ceiling (m / ft) Service ceiling (m / ft) Service ceiling (m / ft) 16,764/55,000
18,800/61,680 18,000/59,055 18,000/59,055 Range: at altitude (km) 1 hr flight
Range: at altitude (km) 3,879 Range: at altitude (km) 3,680 Range: at altitude (km) 4,000 time
ARMAMENT: ARMAMENT: ARMAMENT: ARMAMENT:
Hardpoints 6-8 Hardpoints 12 Hardpoints 12 Hardpoints 0
Wing 2 Wing 2 Wing 2 Wing 0
Underwing pylons - Underwing pylons 6 Underwing pylons 6 Underwing pylons 0
Fuselage 4-6 Fuselage 4 Fuselage 4 Fuselage 0
OTHER: OTHER: OTHER: OTHER:
Manufacture Sukhoi Airframe Manufacture Sukhoi Airframe Manufacture Sukhoi Airframe Manufacture Grumman Airframe
components Su-27/33 components - components - components F-5
First flight 25 Sep 1997 First flight 1993 First flight 18 Dec 1993 First flight 14 Dec 1984
Using materials from Jane's Defence Weekly and various Internel sources
GOSUDARSTVENNOYE UNITARNOYE PREDPRIYATIE AVIATSIONNYI VOYENNO-PROMYSHLENNYI
KOMPLEKS/AK SUKHOI (State Unitary Enterprise, Aviation Military-Industrial Complex/Concern Sukhoi)
SUKHOI S-37 BERKUT
English name: Golden Eagle
Type
Multirole fighter.
Programme
Dedicated `company-funded' research programme to explore post-stall manoeuvrability and `supermanoeuvrability' for
next-generation fighter; despite original purpose, Sukhoi OKB soon began promoting S-37 as alternative `heavy' fighter to
Mikoyan's MFI and, for this reason, it was designed as large, heavy twin-engined aircraft with some `stealth' features and
with room and/or provision for incorporation of operational and mission equipment and systems. Design bureau and
defence ministry sources have recently denied that the S-37 is a prototype of any combat aircraft; daily Red Star stated in
1997 that S-37 has zero priority for Russian air force; however, Russian Air Forces' C-in-C quoted in 1998 as foreseeing
``a future for the S-37''. Funds for programme derived from foreign sales of Su-27 `Flankers'.
First reported as Su-32 in 1996, then as S-32; possibly derived from - or follow-on to - 1982 forward-swept wing (FSW)
demonstrator reportedly seen at Saki test airfield and supposedly codenamed SYB-A in West; existence of such an aircraft
has been denied by Russian sources, although the Tsybin OKB built several forward-swept gliders and rocket-powered
test aircraft in the late 1940s. Reports suggest that the SYB-A was a Sukhoi product, perhaps a converted Su-9. Sukhoi
also used a forward-swept wing on the proposed S-86 propeller-driven corporate transport.
Design reportedly began in 1987. S-32 and S-37 originally had no tailplane, instead having shallow, broad, flat surfaces
extending back from the wing trailing-edge; these later evolved into very narrow-span tailplanes. Reshuffle of designations
continued with use of the Berkut as a `home' for the S-37 designation already employed by a single-engined light fighter
with canard foreplanes and a cranked, cropped-delta wing, probably designed to meet the air forces' LFI requirement. S-37
designation became available when this design project was cancelled.
Prototype (marked `01') first flew at Zhukovsky test airfield, near Moscow, on 25 September 1997; following eighth sortie,
on 27 November 1997, was temporarily grounded for increase of horizontal tail span and area, improved avionics
integration and better tailoring of engines. Total of at least 31 flights by January 1999 and 50 to August 1999, when
reported to be at half-way point of test programme; first phase completed 23 February 2000, after which the aircraft began
a second supersonic phase; this included a brief deployment to the Russian Federation MoD Flight Test Centre at
Akhtubinsk, where the aircraft exceeded M1.0 for the first time on its 88th flight, in August 2000. A third phase (with an
expanded envelope) was due to begin at the end of November 2000, with this planned to include the type's 100th flight.
However, in early 2000, testing was expected to continue for further ``four to five years''. 30є AoA achieved by mid-1999.
Public debut at Aviation Day, Tushino, 15 August 1999.
Customers
After company testing, S-37 may be passed to LII trials centre at Zhukovsky, where some Russian air force participation is
expected. Series production is not planned.
Design Features
Incorporates features and technology applicable to a fifth-generation fighter. Described as `integrated triplane' with short
span, broad chord, tapered foreplanes; forward-swept, slightly tapering wing; and very short span, broad chord horizontal
tail surfaces. Wings reported to incorporate provision for powered folding, without which the aircraft would be too large to fit
in a standard hardened aircraft shelter. Twin tailfins each canted outwards at approximately 6є FSW improves subsonic
agility, high AoA controllability, take-off and landing performance, reduces drag and diminishes frontal radar reflectivity.
Other measures, including radar-absorbent materials and engine air intake shape and internal S ducting, taken to reduce
frontal radar signature. Large, curved LERX above semicircular engine air intakes resemble those of an earlier Sukhoi light
fighter project (a previous carrier of the Su-37 designation). Slightly flattened nosecone enhances supermanoeuvrability.
Expected to demonstrate AoA up to 120є at speeds from zero to supersonic. The aircraft reportedly makes extensive use
of RAM coatings, these having been developed in the late 1980s under project `Astra' which used two modified Su-25
preproduction aircraft.
Major components, such as tailfins, canopy, windscreen and landing gear, appear to be standard Su-27 parts. S-37 01 not
equipped with radar, weapons or mission systems, but conspicuously has provision for their later fitment: forward- and aft-
facing radomes, vented gun bay with cannon port, IRST mockup ahead of windscreen (offset to starboard) and dielectric
panels in leading-edges of tailfins, LERX and foreplanes. Of twin, rear-facing radomes, starboard is on extended mounting
and protrudes beyond trailing-edge of horizontal tail.
Wing swept forward (all data approximate) by 20є on leading-edge (except 24є sweptback gloves) and 37є on trailing-
edge; rounded wingtips. Foreplane leading-edge has 50є sweep and -16є trailing-edge sweep. Horizontal tail swept 70є.
Fin leading-edge sweep of 45є.
Flying Controls
FCS presumed developed from Avionika quadruplex digital FBW system of Su-35 and Su-37, probably with manual
override; credited to Petrov. Wing appears to have two-thirds span leading-edge flaps on forward-swept portion, these
each being in two parts, of which only the inboard has been noted deployed; trailing-edge has plain flaps inboard and
ailerons outboard. Foreplanes may operate differentially and/or in unison. All-moving horizontal tail surfaces; conventional
rudder in each fin.
Structure
Follows Su-27/Su-35 practice, but with wing of 90 per cent composites construction to ensure adequate stiffness.
Landing Gear
Generally as Su-33 (Su-27K) naval version of `Flanker'.
Power Plant
Two Aviadvigatel D-30F6M turbofans, each 93.1 kN (20,930 lb st) dry and 153.0 kN (34,392 lb st) with afterburning. Engine
choice reportedly dictated by other programmes - all AL-41 engines dedicated to Mikoyan MFI; AL-37FU to Su-30MKI and
Su-37 programmes. Potential for replacement with Saturn/Lyulka AL-37FU turbofans with two-dimensional vectoring
nozzles; by R-79M engines; or by three-dimensional AL-41Fs rated at 196 kN (44,092 lb st). Last-mentioned reported in
early 2000 as candidates for retrofit in 2005. Fixed geometry air intakes; rectangular auxiliary intake door for each engine
above mid-fuselage. Unconfirmed reports allege engines have new nozzles which assist cooling of exhaust gases to
reduce heat signature.
Accommodation
Pilot only, on 30є rear-tilted Zvezda K-36DM ejection seat, beneath rear-hinged, Su-27-type transparencies.
Avionics
Integrated avionics suite by Technocomplex. May receive new integrated suite by Kronstadt, including Transas Abris
navigation and landing system.
Radar: Provision, only, in nose to install multimode, phased-array Phazotron radar of unspecified type, with supplementary,
rear-facing radar in starboard tailcone. Planned radar will have range of up to 132 n miles (245 km; 115 miles) and be
capable of simultaneously tracking 24 and engaging eight targets.
Instrumentation: Ramenskoye instruments and displays.
Mission: Provision for Pribor weapons control system.
Armament
Nil. Alleged provision for underwing pylons, wingtip missile launch rails and internal GSh-301 30 mm gun with aperture in
upper surface of port LERX. Some sources report provision for conformal weapons carriage to reduce radar signature.
Dimensions, External
Wing span 16.7 m (55 ft)
Length overall 22.6 m (74 ft)
Height overall 6.4 m (21 ft)
Areas (approx)
Wings, gross 56 m2 (600 sq ft)
Foreplanes (total) 5.7 m2 (61 sq ft)
LERX (total) 2.75 m2 (30 sq ft)
Fins (each) 7.7 m2 (83 sq ft)
Weights and Loadings
T-O weight: normal 25,670 kg (56,592 lb)
max 34,000 kg (74,957 lb)
Wing loading:
normal approx 458 kg/m2 (93.89 lb/sq ft)
max approx 607 kg/m2 (124.35 lb/sq ft)
Power loading: normal 84 kg/kN (0.82 lb/lb st)
max 111 kg/kN (1.09 lb/lb st)
Performance (estimated)
Max level speed:
at S/L M1.12 (756 kt; 1,400 km/h; 870 mph)
at altitude M2.1 (1,188 kt; 2,200 km/h; 1,367 mph)
Service ceiling 18,000 m (59,060 ft)
Range 1,781 n miles (3,300 km; 2,050 miles)
g limit +9
(source: Jane's)
