The Su-15 and Su-15UT are powered by two Tumanskiy R11F2S-300 or R11F2SU-300 axial-flow afterburning turbojets rated at 3,900 kgp (8,600 lbst) at full military power and 6,175 kgp (13,610 lbst) in full afterburner. The R11F2S-300 is a two-spool turbojet featuring a three-stage low-pressure (LP) compressor, a three-stage high-pressure (HP) compressor, an annular combustion chamber, single-stage HP and LP turbines and an afterburner with an allmode variable nozzle. The transonic-flow compressor has no inlet guide vanes; the second-stage blades have snubbers to prevent resonance vibrations. Bleed valves are provided; the R-11F2SU-300 version features air ducts for the BLCS, with a maximum bleed rate of 2.5 kg/sec (5.5 lb/sec) in dry thrust mode only. The accessory gearbox is located ventrally. The engine has a closed-type lubrication system. Starting is electric (by means of a starter-generator), using onboard or ground DC power. Engine pressure ratio at take-off thrust 8.7; mass flow at take-off thrust 66 kg/sec (145.5 lb/sec), maximum turbine temperature 1,175° K. SFC 2.37 kg/kgph (lb/lbst·h) in full afterburner and 0.93 kg/kgp·h in cruise mode. Length overall (including afterburner) 4,600 mm (15 ft 1 in), casing diameter 825 mm (2 ft 8½ in); dry weight 1,088 kg (2,400 lb).
The Su-15T, Su-15TM and Su-15UM are powered by two Tumanskiy R13-300 axial-flow afterburning turbojets rated at 4,100 kgp (9,040 lbst) at full military power and 6,600 kgp (14,550 lbst) in full afterburner. This is likewise a two-spool turbojet with a three-stage LP compressor, a five-stage HP compressor, an annular combustion chamber, single-stage HP and LP turbines and an afterburner with an allmode variable nozzle. The afterburner features annular/radial flame holders and a perforated heat shield. EPR 9.15 at full military power and 9.25 in full afterburner; mass flow at take-off thrust 66 kg/sec, maximum turbine temperature 1,223° K. SFC 2.25 kg/kgp h in full afterburner and 0.96 kg/kgph in cruise mode. Length overall 4,600 mm, casing diameter 907 mm (2 ft 1134 in); dry weight 1,134 kg (2,500 lb).
The Su-15 has powered flight controls with BU-49 or, on later aircraft, BU-220D irreversible hydraulic actuators. Control inputs are transmitted to the aileron and stabilator actuators via push-pull rods, bell-cranks and levers; in the rudder control circuit, cables and rigid linkage are used. The stabilator control circuit includes an ARZ-1 stick force limiter, a differential mechanism and a pitch trim mechanism. Artificial-feel units are fitted but there is no autopilot.
Internal fuel is carried in five integral tanks – three fuselage tanks (No.1, frames 14A-18; No.2, frames 18-21; No.3, frames 21-28) and two wing tanks. The total capacity stated in different documents varies from 8,675 to 8,860 litres (1,907 to 1,949 Imp gal). The ‘wet’ hardpoints under the fuselage permit carriage of two 600-litre (132 Imp gal) drop tanks.
Main 28.5 V DC electric power provided by two 12-kW GSR-ST-12000VT engine-driven starter-generators, with two 15-STsS-45A silver-zinc batteries providing 22.5 V DC as a back-up. 115 V/400 Hz single-phase AC provided by two SGO-8TF engine-driven generators. Two ground power receptacles are provided on the port side of the fuselage. The exterior lighting includes BANO-45 navigation lights at the wingtips, a KhS-39 tail navigation light on the fin trailing edge, and two retractable PRF-4M landing/taxi lights in the wing roots.
There are four hydraulic systems (two primary and two actuator supply systems), each with its own NP-34 or NP-26/1 engine-driven plunger-type pump. The No. 1 primary system operates the landing gear, flaps, airbrakes, artificial-feel unit switch mechanism, the port air intake ramp and auxiliary blow-in door and the port engine’s nozzle actuators. It also performs automatic wheel braking during landing gear retraction The No.2 primary system powers the radar dish drive, the starboard air intake ramp/auxiliary blow-in door and the starboard engine’s nozzle actuators. The two actuator supply systems (main and back-up) power the aileron, rudder and tailplane actuators; the port system features an NS-3 autonomous emergency pump ensuring that the aircraft remains controllable in the event of a dual engine failure. All systems use AMG-10 oil-type hydraulic fluid; nominal pressure 215 kg/cm2 (3,070 psi).
The pneumatic system performs normal and emergency wheel braking, emergency landing gear and flap extension, and operates the inflatable canopy perimeter seal. The system is charged with compressed air to 200 bars (2,857 psi), featuring three 6-litre (1.32 Imp gal) air bottles. There is also a separate pneumatic system charged to 150 bars (2,140 psi) which operates the stabilising gyros of the missiles’ seeker heads.
The cockpit is pressurised (and the canopy demisted) by air bled from the engine’s fifth or seventh compressor stage, depending on rpm. Cockpit air temperature is maintained automatically at +10-20°C (50-68°F) by a TRTVK-45M regulator; the air pressure is governed by an ARD-57V automatic pressure regulator. The oxygen equipment includes a breathing apparatus for normal operation and a separate breathing apparatus used in the event of an ejection. For operations at altitudes up to 10,000 m (32,810 ft) and speeds up to 900 km/h (560 mph) the pilot is equipped with a KM-32 oxygen mask, a ZSh-3 flying helmet (zaschchitnyy shlem) and a VK-3 or VK-4 ventilated flying suit (ventileeruyemy kostyum). For missions involving supersonic flight the pilot wears a VKK-4M, VKK-6 or VKK-6P pressure suit and a GSh-4MS, GSh-4MP or GSh-6M full-face pressure helmet (ghermoshlem).
Fire protection is provided by an SSP-2I fire warning system (sistema signalizahtsiï pozhahra) and a UBSh-6-1 fire extinguisher bottle with two distribution manifolds around the engines.
The navigation and piloting equipment includes a KSI-5 compass system and an RSP-6 instrument landing system (comprising an ARK-10 ADF, an RV-UM low-range radio altimeter, an MRP-56P marker beacon receiver and SOD-57M DME). An RSBN-5S SHORAN and an SAU-58 (or SAU-58-2) automatic flight control system are fitted. The cockpit instrumentation includes a KUSI-2500 airspeed indicator, VDI-30 altimeter, AGD-1 artificial horizon, EUP-53 turn and bank indicator, AM-10 accelerometer (G load indicator), VAR-300 vertical speed indicator, UKL-2 heading indicator, KI-13 flux gate compass, M-2.5 Mach meter, ARK-10 ADF indicator, critical angle of attack warning system and AChKh clock. Air data is provided by main and back-up PVD-7 pitots; the main pitot is located at the tip of the radome.
Communications equipment comprises an RSIU-5V (R-802) VHF radio (or an R-832M Evkalipt radio on the Su-15TM) and, on trainer versions, an SPU-9 intercom. Single-seat versions have a data link receiver making up part of the Lazoor’-M (ARL-SM) GCI system. The aircraft is equipped with an SRZO-2M Kremniy-2M IFF interrogator/transponder, a Sirena-2 or (Su-15TM) SPO-10 Sirena-3 radar warning receiver. An SARPP-12V-1 flight data recorder (sistema avtomaticheskoy reghistrahtsii parahmetrov polyota – automatic flight parameter recording system) is fitted From Batch 11 onwards; the Su-15UM has an MS-61B cockpit voice recorder.
The Su-15 sans suffixe is equipped with an RP-15 Oryol-D58 or RP-15M Oryol-D58M fire control radar in a conical radome. The Su-15T features a Taifoon radar in an identical radome, while the Su-15TM has an RP-26 Taifoon-M radar in an ogival radome. No radar is fitted to the trainer versions. A K-10T collimator gunsight is provided. The standard armament of the Su-15 sans suffixe consists of two R-98R (SARH) and R-98T (IR-homing) medium-range AAMs carried on wing-mounted pylons with BD3-59FK launch rails. The older R-8MR and R-8MT can also be used, but only when the target is attacked in pursuit mode. The missiles are fired singly or in a salvo with a 0.5-second interval. The Su-15TM is armed with two R-98MR (R-98MT) medium-range AAMs and two R-60 short-range IR-homing AAMs on single APU-60 or twin APU-60-2 launch rails; later the Su-15 sans suffixe underwent a similar upgrade, being retrofitted with two extra pylons. The radar-less Su-15UM can carry R-98MT and R-60 AAMs. The fuselage hardpoints can be used for carrying free-fall bombs (Su-15TM only) or UPK-23-250 gun pods, each containing a Gryazev/Shipoonov GSh-23 double-barrelled 23-mm (.90 calibre) cannon with 250 rounds.