DCS Su-27 Flanker Technical specifications

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DCS: Su-27 Flanker
Flight Manual

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DCS: Su-27 for DCS World
The Su-27, NATO codename Flanker, is one of the pillars of modern-day Russian combat aviation.
Built to counter the American F-15 Eagle, the Flanker is a twin-engine, supersonic, highly
manoeuvrable air superiority fighter. The Flanker is equally capable of engaging targets well beyond
visual range as it is in a dogfight given its amazing slow speed and high angle attack manoeuvrability.
Using its radar and stealthy infrared search and track system, the Flanker can employ a wide array of
radar and infrared guided missiles. The Flanker also includes a helmet-mounted sight that allows you
to simply look at a target to lock it up! In addition to its powerful air-to-air capabilities, the Flanker
can also be armed with bombs and unguided rockets to fulfil a secondary ground attack role.
Su-27 for DCS World focuses on ease of use without complicated cockpit interaction, significantly
reducing the learning curve. As such, Su-27 for DCS World features keyboard and joystick cockpit
commands with a focus on the most mission critical of cockpit systems.
General discussion forum: http://forums.eagle.ru

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Table of Contents
INTRODUCTION ...........................................................................................................VI
SU-27 HISTORY ............................................................................................................. 2
ADVANCED FRONTLINE FIGHTER PROGRAMME.......................................................................... 2
FROM T-10 TO T-10S.......................................................................................................... 9
TESTING...........................................................................................................................12
41 RECORDS OF THE SU-27 .................................................................................................15
IN SERVICE .......................................................................................................................16
GENERAL DESIGN ........................................................................................................ 19
DESIGN............................................................................................................................20
SYSTEMS AND AVIONICS .....................................................................................................22
COCKPIT ..........................................................................................................................23
GAME AVIONICS MODE .............................................................................................. 26
NAVIGATION MODE...........................................................................................................28
AIR TO AIR MODE .............................................................................................................29
COCKPIT INSTRUMENTS.............................................................................................. 31
Airspeed and Mach Indicator ................................................................................................................... 32
Pressure Altimeter ................................................................................................................................... 32
Radar Altimeter........................................................................................................................................ 33
Mechanical Devices Indicator .................................................................................................................. 33
AoA Indicator and Accelerometer............................................................................................................ 34
Attitude Direction Indicator ..................................................................................................................... 34
Horizontal Situation Indicator .................................................................................................................. 35
Vertical Velocity Indicator........................................................................................................................ 36
Aircraft Clock............................................................................................................................................ 36
Tachometer.............................................................................................................................................. 37
Fuel Quantity Indicator ............................................................................................................................ 37
Interstage Turbine Temperature Indicators ............................................................................................. 38
Head Down Display (HDD)........................................................................................................................ 38
Radar Warning System............................................................................................................................. 39
PPD-SP Panel............................................................................................................................................ 42
Direct control switch ................................................................................................................................ 42
Trimming Mechanism .............................................................................................................................. 43
Automatic Control System (ACS).............................................................................................................. 44

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SU-27 HUD AND HDD OPERATIONAL MODES....................................................................... 47
Basic HUD symbols....................................................................................................................................47
Navigation Modes.....................................................................................................................................49
Beyond Visual Range Combat Modes .......................................................................................................50
Digital Datalink..........................................................................................................................................57
Work in Complicated Countermeasures Conditions .................................................................................58
Vertical Scanning - Close Combat Mode ...................................................................................................60
BORE - Close Combat Mode......................................................................................................................61
HELMET - Close Combat Mode .................................................................................................................61
Fi0 –Longitudinal Aiming Close Combat Mode.........................................................................................62
Gun Employment......................................................................................................................................63
Air-to-Ground Mode .................................................................................................................................65
Reticle .......................................................................................................................................................66
ELECTRONIC COUNTERMEASURES ......................................................................................... 68
Electronic Countermeasures (ECM) Stations of Su-27 ..............................................................................68
SU-27 WEAPONS......................................................................................................... 71
AIR-TO-AIR MISSILES......................................................................................................... 71
SU-27 MISSILES................................................................................................................ 73
R-27 (AA-10) Medium Range Missiles.......................................................................................................73
R-73 (AA-11) Short Range Missile .............................................................................................................76
AIR-TO SURFACE WEAPONS ................................................................................................ 80
Free-fall Bombs.........................................................................................................................................80
Unguided Aerial Rockets...........................................................................................................................84
RADIO COMMUNICATIONS AND MESSAGES ............................................................... 90
RADIO COMMANDS ........................................................................................................... 90
RADIO MESSAGES ............................................................................................................. 97
VOICE MESSAGES AND WARNINGS ..................................................................................... 100
THEORETICAL TRAINING ........................................................................................... 103
INDICATED AIR SPEED AND TRUE AIRSPEED .......................................................................... 103
VELOCITY VECTOR ........................................................................................................... 103
ANGLE-OF-ATTACK (AOA) INDICATOR................................................................................. 103
TURN RATE AND RADIUS OF TURN ...................................................................................... 104
TURN RATE .................................................................................................................... 106
SUSTAINED AND INSTANTANEOUS TURNS ............................................................................. 107

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ENERGY CONTROL ...........................................................................................................108
SU-27 IMPLEMENTATION.......................................................................................... 109
FLIGHT CONTROL SYSTEM (FCS) ........................................................................................110
Longitudinal Channel ..............................................................................................................................110
Lateral Channel .......................................................................................................................................112
Directional Channel.................................................................................................................................115
NOZZLE CONTROL SYSTEM ................................................................................................117
SU-27 CHECK LISTS .................................................................................................... 119
Engine Ground Start................................................................................................................................119
Engine Shutdown ....................................................................................................................................119
In Flight Engine Restart ...........................................................................................................................119
WEAPONS DELIVERY ........................................................................................................121
Beyond Visual Range Combat .................................................................................................................121
Close Air Combat.....................................................................................................................................124
Air-to-Ground Weapons..........................................................................................................................129
SUPPLEMENTS .......................................................................................................... 132
ACRONYM LIST................................................................................................................132

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INTRODUCTION
The Su-27, NATO codename Flanker, is one of the pillars of modern-day Russian combat aviation.
Built to counter the American F-15 Eagle, the Flanker is a twin-engine, supersonic, highly
manoeuvrable air superiority fighter. The Flanker is equally capable of engaging targets well beyond
visual range as it is in a dogfight given its amazing slow speed and high angle attack manoeuvrability.
Using its radar and stealthy infrared search and track system, the Flanker can employ a wide array of
radar and infrared guided missiles. The Flanker also includes a helmet-mounted sight that allows you
to simply look at a target to lock it up! In addition to its powerful air-to-air capabilities, the Flanker
can also be armed with bombs and unguided rockets to fulfil a secondary ground attack role.
Figure 1: Su-27

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SU-27 HISTORY
SU-27 HISTORY
The Su-27, a Russian fourth-generation single-seat supersonic fighter, is recognised all over the
globe as one of the best combat aircraft of the 20th century. Due to its perfect flight performances
and operational characteristics, the fighter is rightfully popular with pilots and technicians. Top
piloting capabilities of the Su-27 fighter demonstrated during multiple air shows around the world did
not leave anyone indifferent. The Su-27 is in the top lines of the aviation record tables of the
International Aircraft Federation. To the date, the Su-27 is a record-holder of 27 world class flight
achievements. The Su-27 is the forefather of a combat aircraft family of various functionality,
including the Su-27UB trainer, Su-33 ship-borne fighter, Su-30 twin-seat multirole fighter family, Su-
34 tactical bomber and deep modernized fighter Su-35.
To achieve such impressive results, the developers of the fighter had to follow the long and difficult
way. The creation of the fighter in its modern appearance with its current performances to guard the
Russian aerospace as well as that of the Su-27 buyers would not have been possible without
strenuous efforts made by many engineers, designers, scientists, researchers, pilots and military test
experts. The most significant input in the Su-27 development was made by teams of the Sukhoi
Design Bureau and Komsomolsk-on-Amur Aircraft Manufacturing Plant, developers of its powerplant,
radar and guided missile system from the Lyulka-Saturn Company, Tikhomirov Instrumentation
Research Institute and Vympel State-owned Design Bureau respectively. In addition to the above
organisations, the Su-27 fighter was being developed by many other scientific and research
institutions, including the TsAGI, CIAM, GosNIIAS, CNII, a range of other design bureaux and
research institutes that designed and manufactured various systems for the Su-27 fighter. This article
is dedicated to some aspects of the Su-27 development history which began 30 years ago.
Advanced Frontline Fighter Programme
A team of developers from the Kulon Machine-Building Plant headed by Pavel Osipovich Sukhoi
initiated in 1969 the development of an advanced new-generation fighter for the Soviet Air Force and
Air Defence Forces' aviation. By the mid-seventies, a general concept of the new fighter was
formulated in co-operation with a number of science and research institutions. This concept provided
for a high-manoeuvrability long-range fighter with a powerful weapons system and a perfect
sighting/navigation system that would allow the pilot to participate efficiently in both long-range
missile exchange and dogfight. The basic performances of the new fighter were to be of top class
globally while a number of characteristics was to exceed those of its American F-15 counterpart the
American leadership was reasonably vesting its high hopes in. The design bureau was planning to
introduce a number of major innovations and solutions into the design of the new fighter designated
T-10.
In 1970, the Sukhoi design bureau developed the first version of the fighter airframe incorporating
key features of the integrated aerodynamic configuration. The aircraft was to have a lifting body
featuring a smooth coupling of the wing and fuselage, two turbojet engines located in isolated belly-
mounted engine nacelles and two vertical stabilisers. Such an integrated design allowed a significant
improvement of the fighter's aerodynamics and provided for a more spacious interior to
accommodate fuel tanks and various equipment. For the fighter to achieve intended flight
performances within a wide range of altitudes and speeds, the new fighter's wing had ogyval shape

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and a leading edge extension. According to the developers, the leading edge extension was supposed
to ensure required high-lift characteristics during the aerodynamic focus shifting at supersonic speeds
and generate vortice increasing wing, tail unit and control surface efficiency. At the same time,
Sukhoi was engaged in developing a traditional non-integrated version of the same fighter powered
by two adjacent engines, which were located in the fuselage's aft part, and fitted with side-mounted
air intakes and two vertical stabilisers. In 1972, both versions were submitted to the Air Force board
for examination and consideration. The board was to assess proposals submitted by three aircraft
design bureaux (Sukhoi, Mikoyan and Yakovlev) regarding development of an advanced tactical
fighter slated for entering the service with the Soviet Air Force in the early eighties.
Figure 2: First prototype T-10-1
As a result of thorough evaluation and assessment of all versions submitted for consideration, the
proposals presented by Sukhoi and Mikoyan were approved by the board for further development.
The Su-27 (T-10) programme was to be developed into a heavy multirole advanced tactical fighter,
while the MiG-29 programme was to produce a series-built light advanced tactical fighter. Among the
major combat objectives the both fighters were to meet, there was the dogfight and medium-range
aerial combat capability, interception of aerial targets in the front and rear hemispheres both against
the sky and ground as well as the secondary task of ground target destruction. The Su-27, which had
a better fuel endurance, more weapons load and more sophisticated navigation, self-defence and
communication systems, was intended to operate independently within an air group deep behind the
enemy lines at an operational-tactical range of up to 250-300 km, while a lighter and cheaper MiG-29
would operate only at ranges of up to 100-150 km into the enemy-held territory. The Su-27's
weapons control system was expected to ensure successful countering the F-15 fighter, the most
capable fighter of that time available to the potential opponent, as well as successful engagement
when outnumbered by less capable but numerous fighters (for instance, YF-17, YF-16 and J-6).
Besides, the Su-27 fighter was intended for entering the service with the Soviet Air Defence Forces
after its appropriate reequipping and rearmament.

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SU-27 HISTORY
Figure 3: T-10-1 wing
Proceeding from the updated and more specific requirements the client set for the tactical fighter of
the eighties, Sukhoi started in 1972 developing a preliminary design of the T-10 fighter subsequently
followed by the conceptual design stage. During 1970-75, over 15 options of the fighter configuration
were given consideration. Those configurations varied not only in general approaches to the problem
(integrated or classic configuration) but differed in solutions suggested for individual problems
(engine and air intake positioning, landing gear design, type of the control system, etc.). Finally,
preferences were given to the aircraft design with an integrated statically unstable configuration. The
Su-27 was to become the first Soviet unstable fighter with longitudinal in-flight balancing to be
provided by a fly-by-wire control system. Accepting the longitudinal static instability concept (in other
words, "electronic stability") promised a lot of advantages: for the aircraft to balance at a high angle
of attack, the leading edge slat's upward deflection was required with its lift being added to the wing
lift, which allowed significant improvement of the fighter lift with a minor increase in its drag. Due to
the use of the integrated statically unstable configuration, the Su-27 was to acquire outstanding
manoeuvrability allowing the fighter altitude changes unavailable to typical configuration fighters and
an increase in its range of up to 4,000 km without external fuel tanks. There were no other series-
produced fighter in the world boasting similar performances.
The fighter's aerodynamic configuration featured a regular scheme with the empennage being
situated behind the wings on the load-carrying beams on the outer sides of the separated engine
nacelles. The aircraft had twin tails mounted on the engine nacelles. The plane was to be controlled
by the all-moving horizontal stabiliser whose panels could deflect in different directions, as well as by

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ailerons and rudders. The wing high lift devices included flaps. To enable the powerplant to produce
the optimal performances at any speed and altitude, the air intakes mounted under the centrewing
were made controllable by the horizontal ramp. The fore part of the fuselage housed an integral
radar covered by a radio transparent nosecone as well as the cockpit featuring a canopy that
provided good visibility in all directions.
Figure 4: T-10-3
The Su-27 fighter weaponry which included 30 mm high-rate cannon, K-27 medium-range air-to-air
missiles and K-73 or K-14 short-range missiles was to be standardised with that of the MiG-29 light
tactical fighter. The only difference in armament was the warload carried: while the MiG-29 could
house only six missiles, including two K-27 missiles, the Su-27 was capable of carrying eight,
including four K-27s, as well as the K-27E improved longer-range radar-homing and heat-seeking
missiles.
An integrated weaponry control system of both fighters was substantially standardised and, for the
first time in the history of aviation, included two complementing channels - a radar sighting system
and an optoelectronic sighting system, as well as a helmet-mounted sight. The sighting system
initially designed for the Su-27 fighter had better characteristics. The N001 radar was built by the
Phazotron Research and Development Association under the guidance of Victor Grishin. The OLS-27
optics-based detection and ranging system combining an acquisition/tracking IR locator and a laser
rangefinder was developed by the Moscow-based Geophysics Central Design Bureau headed by Chief
Designer D.Khorol.
The landing gear featured a classical tricycle design with the nose strut having been moved far
forward and the gear well placed under the cockpit. The main gear struts were made forward-
retractable into centrewing gear wells with the wheels being turned in the process and the wells'
forward doors serving as air brakes.
The Su-27 fighter powerplant included two powerful and economical AL-31F bypass turbofan engines
producing thrust of 12,500 kg each. They were developed by the Saturn Mechanical Plant headed by
Arkhip Mikhailovich Lyulka and supposed to ensure take-off thrust-to-weight ratio exceeding 1. Low
specific fuel consumption along with about eight tonnes of fuel stored in internal tanks filling most of
the airframe inner space was to ensure required operational range of the fighter.

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SU-27 HISTORY
Figure 5: T-10-1 in the Russian Air Force Museum (Monino)
The Su-27 fighter conceptual and detailed design stages were completed in 1975-1976, and after
issuance of required design documentation and drawings, the manufacturing of first prototypes was
initiated at the Kulon plant. Unfortunately, Pavel Sukhoi did not live long enough to see the fighter -
he died in 1975 to be succeeded by Yevgeny Ivanov. From 1976 on, the Su-27 programme has been
under immedeate guidance of Chief Designer Mikhail Simonov. The first prototype designated T10-1
was completed in early 1977. Due to the lack of the Al-31F turbofan bypass engines, the prototype
was equipped with two AL-21F-3AI engines - a modified version of the series-production AL-21F-3A
engine mounted on other Sukhoi-developed fighters (Su-17, Su-24). After the completion of required
ground checks and run-ups, everything was ready for test flights and on 20 May, 1977 Vladimir
Ilyushin, Sukhoi's chief pilot, took the T10-1 off the ground for its maiden flight. The first prototype
was used to evaluate its key flight performances as well as stability and controllability.
In 1978, the second prototype designated T10-2 was completed though its life was brief. On 7 July,
1978, the fighter suffered a mid-air accident resulting in death of test pilot Yevgeny Solovyov. The
crash was triggered by the plane's oscillation in the longitudinal plane at a supersonic speed, due to
which it suffered an extremely high g-load and disintegrated in midair. The black box recorder
readings showed that the fighter got into an unexplored resonant mode, which caused the mid-air
disintegration of the aircraft. This happened so fast that Yevgeny Solovyov, distinguished test pilot
and Hero of the Soviet Union, had no chance to eject. The after-action review established the actual
reasons for the tragedy and allowed the developer to introduce necessary changes into the fighter's
design. During 1978, preparations for preliminary production of the Su-27 were made at the Gagarin
machine-building plant situated in the Far Eastern city of Komsomolsk-on-Amur. At the same time,
the Sukhoi mechanical plant commenced assembling another two Su-27 prototypes. Unlike the first
two prototypes, those two fighters were to be powered by AL-31F engines. The new powerplant was
500 kg lighter, its thrust was 12 percent higher than that of the predecessor with fuel consumption
being lower. In comparison with the AL-21F-3s, the AL-31F engines had smaller diameter and length
while their nozzles were accommodated with a secondary (bypass) duct control system. On 23
August, 1979, Vladimir Ilyushin took the T10-3 off for its maiden flight. Two months later, the T10-4
joined the flight testing too. At first, both aircraft were used for in-flight engine testing. Then the

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T10-3 was remodeled to be further tested on the Nitka training facility in support of the development
of the Su-27 ship-borne version while the T10-4 was used for the further refining of the weapons
control system.
Figure 6: T-10 cockpit
By the early 1980, as many as three prototypes (T10-1, T10-3 and T10-4) had been taking part in
the Su-27 testing programme with first pre-series aircraft expected to join soon. It seemed that
everything was in line with the schedule and the new fighter would have been fielded in a couple of
years. However, there were staunch objections against commencing series production of the aircraft
in the then airframe configuration, made by the Siberian aviation research institute's (SibNIA)
aerodynamic experts and... Chief Designer Mikhail Simonov himself. According to the SibNIA experts
who had done the bulk of aerodynamic research under the Su-27 programme, several mistakes were
made during the fighter development stage. The combination of the accepted wing planform and
leading-edge extension configuration caused premature vortex flow separation: the non-stationary
airflow around the wing would begin as early as at the 8-to-10 angle of attack (AoA), which would
cause deterioration of the airframe's lifting capability, buffeting and decrease in lateral stability. The
tail unit configuration designed for the T10 would fail to provide required effectiveness of the
longitudinal control surfaces, lateral and directional stability devices. The SibNIA-held T-10 wind

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SU-27 HISTORY
tunnel tests performed in 1975-76 indicated that there was a slim chance of developing a highly
manoeuvrable fighter without dealing first with the above problems.
Figure 7: T-10-10 at museum, Lugansk, Ukraine
The necessity of the Su-27 programme's radical reconsideration was looming ahead. Such
fundamental elements of the fighter design as the form and area of the wing, leading-edge extension
configuration, horizontal and vertical control surface arrangement were have to be redesigned.
Mikhail Simonov was a staunch supporter of such an approach but the Aviation Industry Ministry's
brass had a different opinion. Designer Ye.A.Ivanov was not too keen on taking risk by radically
revamping the design. As a result, first Su-27s were tested in their initial configuration. The flight
tests of the T10-1 and T10-3 corroborated to the Siberian aerodynamics experts' doubts. To make up
for the vertical stabiliser effectiveness decrease resulting in a decrease in the fighter's directional
stability at a high AoA, first planes were fitted on the TsAGI advice with top-of-the-wing-mounted
fences. However, the fences reduced the airframe's lifting capacity and negated the advantage of
using the leading edge extension roots.
The T-10 testing also revealed the failure of the fighter's certain characteristics to match those of the
performance specifications. First of all, that was true for the range: the mismatch between the
required and actual ranges exceeded 20 percent. The Designer General reported to the ministry that
there were two main reasons for non-compliance with certain requirements set in the performance
specifications. Firstly, avionics developers failed to meet the weight limits set out in the avionics
performance specifications. The summary avionics excessive weight comprised a few hundred
kilograms, which, naturally, led to the aircraft's overall weight increase, hampered its manoeuvrability
and reduced its range. Secondly, the engine's specific fuel consumption ordered in the performance
specifications had not been achieved by the developer either. Truth be told, the issue was settled
later when the requirements to the engine's specific fuel consumption were found to be a tall order
which could not be met then. In spite of the T-10's considerable deficiencies revealed during the
research and flight tests, Yevgeny Ivanov hoped, nonetheless, for possibility to gradually hone that

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configuration through minor design modifications, fuel capacity increase, etc. Otherwise, Mikhail
Simonov was pushing hard for radical aircraft reworking, since as early as in 1976-77 a team of his
subordinates in cooperation with the SibNIA scientists developed on their own and later tested in the
wind tunnel a new configuration of the airframe devoid of the deficiencies which the previous
configuration had in abundance. Justice should be done to M.P.Simonov (who went to work for the
Aviation Industry Ministry in 1979 to return to Sukhoi as Designer General in 1983) who managed to
persuade the leadership to risk radical change in the configuration of the fighter that had been
already undergoing tests by then. With the passage of time, this decision proved to be right and led
no matter what to building the aircraft that still - almost two decades later - has been regarded as
one of the best warplanes in the world. Having commenced production of the Su-27 in its final
configuration, Sukhoi confirmed its reputation of a world leader of aviation industry in line with its old
tradition of never fielding mediocre aircraft.
From T-10 to T-10S
The fighter's version featuring the new configuration was designated T-10S by the Sukhoi design
bureau with its full-scale design work starting in 1979. Preliminary attempts to deal with the first T-10
version's glitches and meet the performance specifications' requirements, made by the design bureau
and SibNIA (in the SibNIA the work was headed by Stanislav Kashafutdinov, candidate of technical
sciences) resulted in setting the guidelines for modifying the initial configuration. With the developing
of those guidelines, differences in design between the T-10S and T-10 became even more obvious.
In the end, it became clear that the designers would have to develop an utterly different aircraft.
According to Mikhail Simonov, the only things the T-10S inherited from its T-10 predecessor were the
main landing gear's wheels and ejection seat. Only general principles set up for the Su-27 by
P.O.Sukhoi himself, such as the integrated airframe configuration, statically unstable design with the
aft centre of gravity, fly-by-wire control system, mounting the engines in isolated engine nacelles
with belly-mounted air intakes, etc., were retained.
Figure 8: T-10-21 (T-10S) mockup in the air tunnel (SibNIA)

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The T-10S had a new wing featuring a straight leading edge, an aerodynamic twist and a
reconfigured sharp leading edge extension. Ogyval wing tips lost the ground to traditional permanent
leading edge sweepback angle ones featuring pylons for air-to-air missiles, which resulted, firstly, in
discarding flutter-preventing weights carried by the T-10 and, secondly, in beefing up the number of
missiles from eight to 10. The wing area grew from 59.4 sq.m to 62 sq.m with the wing high-lift
devices being changed drastically. Ailerons and flaps were replaced with unified control devices -
flaperons, wing leading edges were fitted with slats (the T-10 had no leading edge high-lift devices),
the automatic adaptive deflection mode for the flaperons and leading edge slats was ensured
providing for the fighter's "polar curve envelope" flight concept. The airframe's lifting characteristics
were enhanced through the use of the new wings and leading-edge extensions while maintaining the
negative pitching moment at positive angles of attack and extending significantly the range of
operational angles of attack, which ensured satisfactory lateral stability and prevents buffeting.
Figure 9: T-10 evolution
To reduce drag, the fore part of the airframe was reworked: the airframe cross section in front of and
around the cockpit was decreased, canopy's midsection was reduced while its rearward movement
was enhanced, the airframe's fore part cross section in the area of first fuel tanks was increased.
Besides, airframe and spine fairing couplings were introduced along its whole length, spine fairing's
lateral cross section in the airframe's midsection was reduced, central tail boom arrangement was
altered through addition of a cylindrical tip which was an extension of the rear integral tank. At the
same time, the total internal fuel capacity increased making up 9.4 tonnes. Making the shape of the
engine nacelles more graceful while reducing their weight was achieved through fitting the T-10
aircraft with AL-31F engines featuring top-mounted aircraft and engine accessory gearbox (the T10-3

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and T-10-4 were powered by the AL-31F engines featuring bottom-mounted accessory gearboxes).
While preserving the general arrangement of air intakes, the new aircraft had a new foreign-object
damage (FOD) system introduced for preventing FOD during taxiing, run and take-off through the
use of extendable screens in the air intakes' ducts. Supplementary air inlet ramps were added to the
lower surface of the air intakes.
Figure 10: T-10-17 with 10 missiles
To enhance directional and lateral stability through raising efficiency of the corresponding control
surfaces, the empennage underwent substantial redesigning. The two vertical stabilisers were set
wide apart at the reinforced booms on both sides of the engine nacelles with an optimum position for
the stabilisers chosen in the vortex system generated by the leading edge extensions and wing
panels. This resulted in considerable increase in directional stability and controllability of the fighter
at high angles of attack and slipping. Also, the T-10S was fitted with ventral fins increasing its
directional stability and anti-spin performances. Mounting the tails on the tail beams provided an
increase in the tails' and horizontal stabiliser area, as well as to place the stabiliser's actuator fairings
behind the tails. The planeform of the empennage was altered too, while the change in the position
of stabiliser panel rotation semiaxes enhanced their flutter characteristics and allowed the designers
to discard the anti-flutter loads mounted on the T-10. The air brakes - the main landing gear doors
featured by the earlier version and discarded due to horizontal control surface flutter caused by their
extending - were ousted by the large air brake mounted behind the cockpit.
The landing gear was reworked too: main struts were provided with "slant" main pivot, which made it
possible to retract the gear into the wing centre section, thus requiring no folding struts to be
installed. This also allowed to reduce the lifting body's cross section in the area of the landing gear
wells. The nose gear strut was reinforced and moved aft, which enabled better taxiing and decreased
a chance of foreign object damage during taxiing, run and take-off. In general, the fighter's
configuration modification provided the lifting body midsection reduction by 15 percent, which led to
reduction of drag by 18-20 percent in the subsonic and supersonic speed range. This, combined with
an increase in the airframe's lifting characteristics as well as lateral and directional stability and
controllability in all three planes in every flight mode, provided the aircraft with superior
manoeuvrability with special emphasis put on high angles of attack and met the requirements set for
the fighter's range.

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SU-27 HISTORY
Testing
In 1980, when the new-version prototype assembly was in full swing at Sukhoi, the pre-production
batch assembly was nearing the end at the series production plant in Komsomolsk-on-Amur. As far as
their design was concerned, they were the deadringers for the T10-1 and T-10-2 prototypes with only
difference being their canted tails resembling those of the T10-3 prototype. Their powerplant still
retained the AL-21F-3AI engines. Despite the fact that the planes had little in common with the
future series-made Su-27, it was decided against cancellation of the pre-production batch. The
decision was made to use them for honing the weapons control system and other equipment as long
as first T-10S were being manufactured and put through initial stages of the testing programme. This
was intended to make up for inevitable dragging behind the schedule due to the need of reequipping
the production lines for manufacturing the new-configuration aircraft. The first aircraft of the pre-
production batch designated T10-5 was finished in July 1980 and followed in the same year by the
T10-6 and T10-9 (numbers 7 and 8 were assigned to first T-10Ss). In 1981, the Komsomolsk-based
plant produced another two fighters - the T10-10 and T10-11, thus making five flying prototypes of
the pre-series batch aircraft designated Su-27, Type T10-5 to discern them from future series-built
aircraft. By 1982, there have been produced nine initial-configuration aircraft and one for static tests
including those assembled at the Sukhoi plant.
Sukhoi completed the assembly of the first T-10S prototype designated T10-7 (a.k.a T10S-1) in early
1981 and in April 1981 it made its maiden flight piloted by test pilot V.S. Ilyushin. Also in 1981, the
static version (T10-8, or T10S-0) and the second flying prototype featuring new configuration were
built. From 1981 on, the Su-27 programme has been headed by Alexei Knyshev who has been the
aircraft's Chief Designer ever since. The T10-7 and T10-12 were used to determine main
performances of the new-configuration fighter, its stability and controllability, as well as to evaluate
the new powerplant featuring top-mounted accessory gearboxes. However, both aircraft were not
destined to fly long. On 3 September, 1981, the T-10-7 was lost due to a fuel system malfunction.
Vladimir Ilyushin had to punch out while the fighter with its tanks nearly empty hit the ground in a
fireball. On 23 December, 1981, the T10-12 crashed too due to entering uncontrolled spin while
performing deceleration from the max speed. The fore part of the air frame was destroyed resulting
in the aircraft hitting the ground. The test pilot, Aleksandr Komarov, died in the crash.
It proved to be impossible to determine all reasons for the crash. However, in 1983, Sukhoi's test
pilot Nikolai Sadovnikov found himself in a similar situation while flying one of the first series-
produced Su-27s - the T10-17. During the low-altitude high-speed level flight, Sadovnikov's fighter
suffered destruction of a leading edge slat and part of the wing panel with the debris damaging
vertical stabilisers. Thanks only to the high skills of the pilot (who was later awarded the title of Hero
of the Soviet Union and set quite a few world records), the sortie did not end up in a crash. Nikolai
Sadovnokov landed the damaged fighter with most of the wing panel missing and a tail clipped, thus
providing the developers with precious information to rake their brains over. It was found out later
that the
reason was a mistake in the calculation of the hinge moment emerging due to the deflection of the
adaptive leading edge flap in certain flight modes. Urgent measures were taken to rework the design,
including the reinforcement of the airframe and wings as well as the development of lesser-area
adaptive leading edge slats.

[SU-27]
DCS
Eagle Dynamics
13
Figure 11: T-10-17 in a test activity
In 1982, the new fighter's testing programme was joined by first new-configuration aircraft
manufactured in Komsomolsk-on-Amur, namely: the T10-15 (later converted into the P-42 record-
maker), T10-16 and above-mentioned T10-17. The fly-out of the first series-built Su-27 took place on
2 June, 1982. The next year, Komsomolsk-based plant delivered another nine fighters, namely, T10-
18, T10-20, T10-21, T10-22, T10-23, T10-24, T10-25, T10-26 and T10-27, most of which were used
in the Su-27 joint official testing held in parallel with establishing series production of the new aircraft
and its fielding with line units. The work on the T10-5 pre-series batch being in full swing too. The
testing resulted in the substantial reworking of the fighter design. Thus, the fore part of the airframe
and the wings were reinforced with the existing fighters being outfitted with additional external
reinforcing plates and those under construction being given reinforced primary structural members
and skin panels. The shape of the tail tips was altered too with previously-designed tail-mounted
weights being discarded. The hinged part of the canopy was made to move up and rearwards (while
earlier it was rear-sliding) with an additional behind-the-headrest metal casement being incorporated
into it. To house the chaff dispenser, the length and height of the flipper - a rear-fuselage bay
between the centre bean and engine nacelles - were increased. The wingtips were modified to carry
ECM pods instead of air-to-air missile launching rails.
In 1984, first Su-27s were fielded with the Soviet Air Force followed by almost a hundred more
fighters having been produced by the end of the next year as well as by Air Force and Air Defence
Forces' units mass transition to the new fighter. The Su-27 joint official testing was completed in the

DCS
[SU-27]
14
SU-27 HISTORY
mid-80s. Its results testified to the fact that a really outstanding aircraft had been made, which was
second to none among the fighters as far as its manoeuvrability, range and combat effectiveness
were concerned. However, certain avionics components required the additional testing held under
special programmes after the joint official testing was over. With the avionics problems resolved, in
1990 the Su-27 was officially adopted in the inventory of the Soviet Air Force and Air Defence Forces
aviation.
Figure 12: T-10-33
Due to the fact that the Su-27 differed considerably from the rest of Soviet fighters both in
performances and weapons control system, navigation suite and other equipment, its twin-seat
combat trainer version designated Su-27UB had to be designed. It was supposed that retaining the
full avionics and weapons suites inherited from the combat version would enable the twin-seater to
be used as an effective combat aircraft. Moreover, considering the Su-27's range and fuel endurance,
the crew of two was supposed at times to be a better option.
The Sukhoi team had begun designing the Su-27UB (developer's designation T-10U) in the late
seventies even before the testing of first new-configuration aircraft commenced. The developer was
tasked with providing a high degree of unification of the single-seater and twin-seater's avionics
design with the fighter retaining its superior performances. In 1980, the predesign work was
completed. The Su-27UB's aerodynamic configuration mainly matched that of the single-seater. The
primary differences lay in the design of the airframe fore part which incorporated a two-seat tandem