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Basic information
Designation: Su-33UB (Military), Su-27KUB (Manufacturer)
Name: Flanker-D (Official), No nickname given
Role: Fighter, Ground Attacker, Trainer
Crew: 2
Manufacturer: JSC Sukhoi Company & OKB
Service life: 1999-2009
Usage in battle & in the game
The Su-33 UB is a rather big and maneuvrable aircraft, able to carry a high range of weaponry being the base of the Su-34. Having a machinegun exactly like the Su-33, this aircraft is able to do fighter missions aswell as ground striking with a pinpoint precision thanks to its avionics. In the game, this aircraft would be able to do the same actions as an Su-24 combined with the fighter capabilities on par of those of the Su-27SM.
History
When the “heavy aircraft-carrying cruiser” Admiral Kuznetsov (Izd. 1143.5) began sea trials in 1989, it was equipped with the Su-27K (Su-33) for air superiority and the Su-25UTG, a shipborne variant of the Su-25, for pilot training. However, the Su-25UTG’s performance in terms of speed, flight behavior, and offensive capability couldn’t match the Su-27K, leading to a need for a more suitable training aircraft for transitioning to the Su-33.
Initially, the Su-27UB was used to continue training pilots who began on the Su-25UTG, but since it couldn’t land on the Kuznetsov, this solution was temporary. Soviet engineers proposed a training version of the Su-33 under the Su-27KUB project, which had potential for both training and specialized variants. Unfortunately, the project was abandoned due to budget constraints and a lack of interest from the Russian Navy, despite being well advanced in development.
The dissolution of the USSR saw many ambitious military programs scrapped despite significant investments. Some were deemed unnecessary for the new Russia, but the Su-27KUB remains a missed opportunity for naval aviation, which has since had to improvise with various aircraft to train onboard pilots.
The Su-27KUB: A Brief Historical Overview
The development of a training variant of the Su-27K dates back to the mid-1980s. A directive from the Soviet Council of Ministers on April 18, 1984, initiated the creation of a carrier-based version of the Su-27 and included a clause for a training variant. The Su-27KUB’s development passed through several stages, starting with the T10KM-2 project, which was short-lived due to a lack of funding. Despite this, Sukhoi engineers revived the concept under the name Su-27KU (Shipborne Training), featuring a side-by-side cockpit similar to the Su-34.
Other than the cockpit, the Su-27KU was largely identical to the Su-33, except it lacked a weapons system. A mock-up of the new cockpit was presented in 1987, sparking significant interest, and development of the Su-27KU progressed. Engineers even envisioned several specialized variants, including the Su-27KTZ for aerial refueling, the Su-27KPP for electronic warfare, and the Su-27KRTs for reconnaissance. However, these projects were eventually abandoned due to financial issues.
The need for a dedicated training aircraft became apparent after the first deployments of the Admiral Kuznetsov in 1995-96, as pilots struggled to transition from the subsonic Su-25UTG to the faster Su-33. This led to the Su-27KU project being revived in 1996, now with the added capability of combat missions, and the aircraft was renamed the Su-27KUB (Shipborne Combat-Training).
To minimize costs, Sukhoi repurposed the T10K-4 prototype, which had been used for Su-33 development, and converted it into the Su-27KUB-1. This involved significant modifications, including the addition of a new cockpit. The prototype made its first flight as the Su-27KUB-1 on April 29, 1999, and testing proceeded, including trials at sea aboard the Admiral Kuznetsov. However, an in-flight incident in 2000 nearly destroyed the aircraft, though it was repaired and resumed testing.
In 2001, work began on a second prototype, Su-27KUB-2, but this was delayed due to technical issues, and the project never fully materialized. The Su-27KUB-1 continued testing until 2009, but by then, Russia had opted for the MiG-29K(UB), supported by India’s financing of its development. As a result, the Su-27KUB was sidelined.
Ultimately, the Su-27KUB project was a victim of its timing. Though it had significant potential, shifting political priorities and financial constraints led to its abandonment. Today, the Su-27KUB-1 remains parked at Zhukovsky, while the unfinished Su-27KUB-2 airframe sits in storage at KnAAZ, marking the end of a promising but ill-fated chapter in Russian naval aviation.
From a technical standpoint
The Su-27KUB (Корабльный Учебно-Боевый / Naval Training and Combat), produced at the KnAAZ plant in Komsomolsk-on-Amur, was designed as both a training and combat aircraft. In addition to its training functions, it can perform air superiority missions, ground strikes, and anti-surface warfare. This multi-role capability sets it apart from the earlier Su-27KU project, which lacked offensive abilities.
Seen alongside the Su-33, the Su-27KUB prototype draws heavily from the Su-33 (Su-27K) platform. Since we’ve already covered the Su-33 in depth, we’ll focus here on the major differences with the Su-27KUB. Notably, only one Su-27KUB prototype was produced, so unless otherwise noted, we’ll refer to the model as Su-27KUB, rather than Su-27KUB-1 or T-10KUB-1.
Description and General Design
While based on the Su-33, the Su-27KUB features a redesigned front fuselage section. The cockpit, resembling the ovoid shape of the Su-34 (though more streamlined), is enlarged to seat two crew members side by side. This design helps improve pilot communication, visibility, and adaptability for carrier operations, and also allows for increased fuel capacity or electronic systems.
Unlike the Su-33, the Su-27KUB’s canards are integrated into its flight control system, enhancing maneuverability. The aircraft’s wings are also larger to accommodate its heavier weight and feature modified leading edges to improve airflow.
Naming and Configuration
Officially, the aircraft is designated as the Su-27KUB, with the project code T-10KUB (derived from the Su-27’s T-10 project code). The name Su-33KUB, though sometimes used, is inaccurate, as the Su-33 is the naval version of the Su-27, with “K” denoting carrier-based aircraft.
The Su-27KUB’s side-by-side cockpit configuration was chosen for improved communication between the instructor and pilot, and to facilitate carrier landings using the Admiral Kuznetsov’s Luna-3 landing aid system. The forward placement of the cockpit, along with the slightly downward-sloping fuselage, gives the crew excellent downward visibility, which is vital for carrier operations.
Comparison of the wing dimensions of the Su-27KUB with the Su-33:
• Wingspan: 15.9 m (Su-27KUB) / 14.7 m (Su-33)
• Wing area: 71.4 m² (Su-27KUB) / 67.84 m² (Su-33)
Structural Modifications
The Su-27KUB retains the three-plane design of the Su-33 but with significant changes. Its canards are larger, with a modified angle, and the wing is expanded to support its greater takeoff weight. The wing’s foldable hinge is also moved 1.5 meters outward compared to the Su-33, resulting in a slightly larger footprint when the wings are folded. Furthermore, the aircraft’s horizontal stabilizers are bigger and remain fixed, unlike the wings.
In terms of general dimensions, the following figures (to be taken on the basis of the first prototype produced, the second having remained unfinished) are available:
• Length. 21.2 m
• Wingspan: 15.9 m
• Height: 5.7 m
• Wing area: 71.4 m²
• Maximum take-off weight: 38.8 tonnes (33 tonnes for a Su-33)
Another innovation is the inclusion of a computerized system that optimizes airflow over the wing, improving the aircraft’s aerodynamics. The Su-27KUB’s rudders are also slightly enlarged compared to the Su-33.
Landing Gear and Performance
The Su-27KUB shares its landing gear with the Su-33, featuring a two-wheeled nose gear and single-wheeled main gear. The nose gear is equipped with a telescopic leg for short takeoffs. For the unfinished second prototype, the landing gear was expected to differ due to structural changes.
Engines and Power
Initially, the Su-27KUB was equipped with two AL-31F series 3 turbojets, the same as those on the Su-33. These engines feature enhanced anti-corrosion protection and emergency afterburners. Later, it was upgraded with thrust-vectoring AL-31FP engines, improving takeoff performance and agility. A further upgrade to AL-31FM-1 engines, with increased thrust (135 kN), was planned and was implemented in 2005.
Each engine has a power of:
• 75.2 kN dry
• 122.5 kN in post-combustion
• 125.5 kN in emergency afterburner
Performance Specifications
While the Su-27KUB’s performance depends on its engine, some key figures include:
- Max speed at sea level: 1,300 km/h
- Max speed at altitude: 2,120 km/h
- Range: 3,200 km on internal fuel
- Ceiling: 17,000 meters
- Takeoff run: 400-450 meters
- G limit: +/-8.5
Despite its larger dimensions, composite materials were used to keep the aircraft’s weight down, especially in the fins. The Su-27KUB maintains a thrust-to-weight ratio of 0.66 at maximum takeoff weight (38.8 tonnes).
The Su-27KUB, also nicknamed “Kubik” (Cube), remains a unique development in the Flanker family, combining training capabilities with offensive combat roles. While only one prototype was built, the design reflects a significant evolution of the Su-33, optimized for multi-role carrier operations.
Armament & payload
On-board armament:
Sources differ on this issue (as the existing prototype was never armed) but it appears that the Su-27KUB was designed to have twelve hardpoints allowing it to carry (according to sources) between 6.5 and 8 tons of weapons. Given that the Su-33 can carry 6.5 tons of weapons and given the modifications made to the Su-27KUB as well as to its wings and airframe; the hypothesis of an increased offensive load is perfectly plausible.
The hardpoints were distributed in the same way as on the Su-33:
• 8 hardpoints distributed evenly under sail
• 2 carrying points distributed equally under each air inlet
• 2 carrying points distributed in a row between the air inlets
The weapon system planned to equip the Su-27KUB being derived from that developed for the Su-27M, the Su-27KUB would therefore have been able to carry a large range of weapons making the Su-27KUB a versatile aircraft capable of carrying out all types of strikes (air-to-air/air-to-sea/air-to-ground).
• Air-to-air weapons: R-27ER, R-27ET, R-73E, R-77
• Air-to-sea weapons: Kh-31A, Kh-31AM, Kh-35, 3M80 Moskit
• Air-to-ground weapons: Smooth bombs, guided bombs, rockets
Like all other representatives of the Su-27 family, the hardpoints would have been specialized in relation to the loads: it is quite obvious to understand that the 3M80 Moskit missile would have found a place on the ventral loads between the two reactors. It therefore appears very clearly that unlike the Su-33 which has above all an air-to-air capacity coupled with a very limited air-to-ground capacity, the Su-27KUB was
from the outset envisaged to have a complete, versatile carry and making the latter a device radically modifying the
capabilities offered by the embarked air group.
Finally, the Su-27KUB has a 30 mm GSh-301 cannon located to the right of the pilot near the wing root. This cannon is fed with 150 shells, it has an impact capacity of 200-800 m for air targets and 1,200-1,800 m for ground targets.
Countermeasures and Electronic warfare:
As a prototype based on the T-10K prototype, the Su-27KUB lacked countermeasure and electronic warfare systems, which were of no use during the aircraft’s testing.
However, it is reasonable to assume that the basic equipment would be at least identical to that of the Su-33, i.e.:
• APP-50 Decoy Launcher for 50mm Thermal Decoys
• L-150 Pastel Radar Warning System
• External jamming pods L005S Sorbitsiya-S or SAP-518
Of course, since the Su-27KUB had more modern and less bulky electronics, this freed up space in the aircraft to install more modern electronic warfare equipment. But this is not detailed in the available literature, so we cannot learn more about the issue.
Firing system
The first prototype Su-27KUB did not have a firing system, in fact, designed to test the behavior of the aircraft, validate the technical choices made, detect potential problems (and correct them); the need for a firing system was not initially felt. The second prototype that was not completed was to have a complete firing system, the latter being the Su-27M firing system installed on the Su-27KUB.
Although the firing system is missing, the Su-27KUB-1 prototype will still receive its two main sensors:
• A Phazotron Zhuk-MS radar
• An OLS-27K infrared monitoring system
The first main sensor, the Zhuk-MS (Модернизированная Сухого) X-band radar developed by Phazotron for the Su-27 family, consists of a flat electronically scanned antenna with a diameter of 980 mm and offering a maximum power of 6 kW. In Air-Air mode, it can track up to ten targets and in engage four simultaneously, the detection capacity offered going up to 130 km for an aerial target having a RCS (Radar Cross Section) of 5 m².
For ground or sea targets, it is capable of detecting a bridge at 130 km and a destroyer-sized target at 300 km.
The Su-27KUB-1 will be re-equipped in the course of 2003 with the N031 Zhuk-MSF radar (Жук Модернизированная Сухого Фазированная) which as its name suggests is a modernized version of the Zhuk radar offering increased detection and tracking capacity. Unlike its predecessor, it is a PESA (Passive Electronic Scanned Array) radar composed of an antenna with a diameter of 980 mm and comprising 1662 modules which was initially developed as part of the Su-30MK3 project for the PLAAF (Chinese Air Force) and Su-37, the latter two ultimately not materializing. The Zhuk-MSF has a scanning capability on the azimuth as well as the elevation of 140° (±70°); in Air-Air mode, it can track up to twenty-four targets and engage eight simultaneously, the detection capacity offered going up to 180 km for an air target with a RCS (Radar Cross Section) of 5 m². As for ground or sea targets, it is able to detect a bridge at 130 km and a target the size of a destroyer at 300 km.
Sources
Su-27KUB (Su-33UB) – Su-27 Flanker Family
[Dossier] Le Sukhoï Su-27KUB: une opportunité manquée? – Red Samovar
- Yes
- No
