MILAVIA > Aircraft > Su-15 > Variants Last updated: 5 May 2010
MILAVIA Aircraft - Sukhoi Su-15 'Flagon'

Su-15 'Flagon' Variants Overview

NOTE: Below you will find an extensive list of proposed and actual variants of the Su-15, although extensive it may not be 100% complete or accurate. Series-produced variants that have been in operational service are highlighted.

1. Development/Pre-Production Prototypes: BACK TO TOP
T-58 (1) Original Su-15 (T-58) aircraft for the Su-15-40 interception system powered by a single Lyul'ka AL-7F2 turbojet. The aircraft was based on the Su-11, but had rectangular side intakes, drawing on experience with the experimental P-1 and T-49 . The front air intake of the Su-11 design was not suitable because of the large Oryol radar. Construction of prototypes not completed, but airframes used for T-58D.
T-58 (2) Alternative T-58 design with two Metskhvarishvili R-21F-300 turbojet engines, uprated version of the R-11F-300 engine (MiG-21).
T-58D-1 First prototype adapted for two engined layout. Received less powerful R-11F2S-300 engines, since R-21 engine was not ready yet. Air intakes were increased in size for greater air flow required by the R-11 engines, giving the aircraft a slim waist. It was not yet equipped with radar and thus had a shorter nose. First flight 30 May 1962. Several improvements were introduced in 1963-64. In January 1965 the T-58D-1 received new cranked wings and eventually transformed into the T-58VD STOL testbed.

T-58D-2 Second prototype. First flight on 4 May 1963. It was equipped with the Oryol-D58 radar resulting in a longer and wider nose than on the T-58D-1. Later, the T-58D-2 was used as testbed, T-58L.
T-58D-3 Third prototype, first flown on 2 October 1963. Revised fuselage shape. Central part (waist) of the aircraft was straightened adding space for additional fuel tanks. In 1965-1967, the T-58D-3 was used for testing the modernised Oryol-D58M radar and SAU-58 flight control system.
T-59 Parallel development for an interceptor fighter configuration. T-59 has the TsP radar and engine intake similar to that of the T-49.
T-60 Another development similar to the twin-engined T-58 but with oblique rectangular air intakes similar to those of the MiG-25.
2. Basic Su-15: BACK TO TOP
Su-15 (T-58D) T-58D was the first version to enter series production. Being designated Su-15 it entered service in April 1965, ASCC NATO designation Flagon-A. Full-scale production began in 1966 and continued until the end of 1970. Initially operated with R-8M1 missiles. It was equipped with the RP-15M Oryol-D58M radar and Tumanskiy R-11F2S-300 turbojets.
T-58M Project based on the modification of the Su-15 into a tactical bomber with vertical lift engines. The design extensively changed the fuselage design with additional air intakes on top and exhausts under the fuselage. The project ultimately resulted in the Su-24.
T-58VD T-58VD, NATO Flagon-B, was a testbed for the vertical engine configuration for the T-58M. Converted from T-58D-1 prototype, three small RD36-35 engines were placed inside the fuselage for short take off and landing. First flight 6 June 1966 by Yevgeniy Solovyov. Tests ran until June 1967. Because of reduced room for fuel in the fuselage because of the engines, range was unsufficient for further development.

Trainer resulting from the U-58 project for a two-seat training version of the Su-15. To speed up development of a trainer, it was decided to remove radar, datalink and RWR. The prototype maiden flight took place on 26 August 1968. Series production started in 1970 and continued until 1972. The fuselage was lenghtened by 45cm and the front fuel tank was reduced by 900 litres, to make room for the instructor cockpit behind the front cockpit. This was somewhat compensated with an additional 190 litre tank in the rear fuselage. A retractable periscope provided forward vision for the instructor. Often Su-15UT can be seen fitted with dummy R-98 missile. NATO 'Flagon-C'.
U-58B Designation for the armed version of the U-58 trainer, as requested by the PVO back in 1965. One prototype of the two-seat combat trainer was built, fitted with Taifun radar. First flight 24 June 1970 by A. Gribachev. Tests stopped because of unacceptable forward shifted centre of gravity caused by the radar.
1969 onwards
From the 11th production series in 1969, the Su-15 was fitted with a new wing to reduce take-off and landing speeds and inflight induced drag. The cranked wing with the outer panel swept at 45 degrees was tested on the T-58D-1 prototype in 1966. The aircraft was also fitted with a UPS system, which uses blown air from the engine compressor to enable higher flap deflection. Engines adapted for UPS were designated R-11FSU-300. However the compressors delivered insufficient airflow to make the system effective. NATO designation for rewinged aircraft was 'Flagon-D', Soviet designation remained Su-15.
1973 onwards
From 1973/1974 all new-build and existing aircraft were fitted with K-10T sight and small inner-wing pylons to enable armament of R-60 missiles.
Project in 1966-67 proposing fitting the Su-15 with Smerch-A radar and K-40 missiles of the MiG-25P. The aircraft would also be fitted with two D-30 turbofan engines.
Design proposal for a supersonic ground-attack aircraft in 1969-1970 based on the Su-15. The MiG-27 won the competition.
T-58N Designation used for the proposal of a modernised Su-15 capable of deploying nuclear tactical weapons.
3. Second Stage Su-15: BACK TO TOP
Su-15 fitted with the Taifun (Typhoon) radar, a variant of the Smerch-A radar from the MiG-25P modified for the reduced space and electrical power of the Su-15. The Su-15T was also fitted with more powerful R-13-300 engines, adjusted air intakes, a longer front leg, SAU-58 automatic flight control system, and some new and upgraded navigation, communication, datalink and RWR. The new engine resulted in slight improvement of acceleration, range, and enabled proper operation of the UPS system. First flight 31 January 1969 by Vladimir Krechetov. Ten Su-15T were built in 1970-71 when defects in the Taifun were revealed.
Alternative proposal to Su-15T, fitting the aircraft with the Korshun-58 radar. Work started in 1965 but was cancelled in favour of the Su-15T in 1967.
(T-58TM) (early)
Fitted with the modernised RP-26 Taifun-M radar, series production of the Su-15TM was started in Late 1971. The Su-15TM was part of the modernised interception complex designated Su-15-98M, together with the R-98M (K-98M) missiles. The Su-15TM also had the modifications of the Su-15T and late production Su-15 aircraft, including provision for underbelly gun pods and the additional wing pylons for R-60 missiles. NATO 'Flagon-E'.
(T-58TM) (late)
The cone shaped radome was unsuitable for the more powerful Taifun-M radar and resulted in unwelcome radar pulse reflections inside the aircraft nose. Late production models, starting with the 8th series, were therefor fitted with an ogival shaped radome. The underfuselage pylons were replaced with a type capable of the UPK-23-250 gun pods as well as boms, rockets, or tanks. Also the underwing pylons were replaced and made capable of these weapons. Late production aircraft fitted with the SAU-58-2 flight control system and Vozdukh to intercept low-attitude targets. NATO recognised the Su-15TM with ogival nose, as a new variant, and designated it 'Flagon-F'. Also western sources reported the designation Su-21 for this variant, but this was never used by Russian sources. Production ceased in 1975.
Two-seat combat trainer developed from the late production Su-15TM. Length of the fuselage and internal fuel tank capacity remained the same this time. Although the Su-15UM has no radar, it was fitted with the ogival shaped radome anyway. But it lacked the SAU-58, datalink, RWR and navigiation system of the Su-15TM. It could be armed with R-98MT and R-60 IR-guided missiles as well as gun pods. First flight U-58TM prototype 23 April 1976 by Vladimir Vylomov and V. Belanin. Small number produced between 1976 and 1979, last series produced Su-15. NATO reporting name 'Flagon-G'.
Converted Su-15TM aircraft with R-25-300 engines. The additional thrust resulted in improved acceleration and speed at low altitude. Also ceiling and range were improved. Testing took place from 3 July until 20 December 1972. The Su-15bis passed the tests, but never entered series production because of an insufficient rate of production of the R-25-300 engine for both Su-15bis and MiG-21bis, the latter was considered more important.
4. Su-19 Plans: BACK TO TOP
Proposed development in the late 1960s/early 1970s to modernise the Su-15TM. The Su-19 would receive a new wing of ogival shape and two R-25-300 turbojet engines, as on the Su-15bis. The new wing and fuel system, would increase aircraft range and endurance.
Su-19M Su-19 with more advanced Tumanskiy R-67-300 turbofans, each producing 78.44 kN (17,637 lb) thrust, which would improve acceleration.
5. Su-15 Flying Testbeds: BACK TO TOP
T-58L L stands for Lyzhnyi = skid. T-58D-2 with lubricated skid landing gear and longer front leg installed. First flight 6 September 1965, tests continued until 1973. Landing skids were abandoned but the longer front leg entered production on Su-15T produced since 1969.
T-58R Designation used for a series produced Su-15 with Relyef terrain-following radar installed in the nose instead of the radar. First flight in May 1972. Relyef was destined for the Su-24.
LLSu-15 Su-15 with bort number 16 used by the Flight Research Institute at Zhukovsky for testing Soviet chaff and flare dispensers for self defence of aircraft of various classes. Later also used for electronic warfare devices. In 1981-82 the LLSu-15 tested changeable inflight stability and steerability, and a side control stick.
Su-15 IFR First pre-series aircraft (c/n 0015301) was used in 1974 for testing an inflight refuelling system for tactical aircraft within the Sakhalin-6A programme carried out for the Su-24 (T-6). The aircraft carried a refuelling UPAZ pod suspended under the fuselage. Su-15TM (c/n 0215306) was equipped with a fixed refuelling probe on the right of the nose. The Sakhalin system is now common on Russian aircraft, although it was not used by the Su-15.
- Su-15 designation was also used for Sukhoi's earlier twin-engines swept-wing interceptor design, which was designated 'P' internally. The prototype first flew on 11 January 1949 and was lost on 3 June 1949. A second prototype was never finished.
- Su-21 is an incorrect designation for late production Su-15TM, given by Western press.
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