I don't know why. When my first time I play lock on, I found Su-27 can't use R-77.
now after I download v1.02, I found I can't even use R-27EM & R-27AE anymore. And they removed mirror as well. That's ridiculous!
Why can't the just do everyone a favour --- upgrade it to Su-27SK?

The aircraft is equipped with a NIIP Tikhomirov N001E Myech coherent pulse Doppler radar with track-while-scan and look-down/shoot-down capability. The radar has a maximum search range of 240km, and a target engagment range of 80~100km in the forward hemisphere and 40km in the rear hemisphere. The radar has the capacity to search, detect and track up to ten targets with automatic threat assessment and proritisation.

The aircraft has an OEPS-27 electro-optic system, which includes an infrared search-and-track (IRST) sensor collimated with a laser rangefinder. The range of the electro-optical system is 40~100 km, depending on the aspect angle presented by the target.

For better close air combat performance, the pilot is assisted by a RLPK-27 holmet-mounted sight (HMS).

A 30 mm GSh-301 cannon is fitted internally with 150 rounds of ammunition. 10 hardpoints (4 under fuselage, 4 under wings, and 2 on wingtips) are available to carry payload of up to 8,000kg.

For air-to-air missions, the aircraft could carry 6 R-27 (AA-10 Alamo) semi-active radar-homing medium-range air-to-air missiles (MRAAMs) and 4 R-73E (AA-11 Archer) IR homing short-range air-to-air missiles (SRAAMs). Alternatively the aircraft could carry 2 wingtip ECM pods.

The Su-27s in service with the PLAAF does not possess precision strike capability. They can carry unguided rocket launchers and free-fall bombs for conventional strike missions
The Su-27SK is equipped with a new electronic countermeasures suite for individual aircraft, and for mutual and group protection in the forward and rear hemispheres. The countermeasures system includes a pilot illumination radar warning receiver, chaff and infrared decoy dispensers, and an active multi-mode jammer located in the wingtip pods.

The Su-27 is powered by two Lyulka Engine Design Bureau (NPO Saturn) AL-31F turbofan engines. Each engine is rated at 17,857 lb (79.43 kN) dry and 27,557 lb st (122.58 kN) with afterburning. The Su-27s in service with the PLAAF only use internal fuel tank and do not carry any auxiliary tanks
The Su-27SK is a highly integrated twin-finned aircraft. The airframe is constructed of titanium and high-strength aluminum alloys. The engine nacelles are fitted with trouser fairing to provide a continuous streamlined profile between the nacelles and the tail beams. The fins and horizontal tail consoles are attached to tail beams. The central beam section between the engine nacelles consists of the equipment compartment, fuel tank and the brake parachute container. The fuselage head is of semi-monocoque construction and includes the cockpit, radar compartments and the avionics bay.

Each engine has two air intakes: a primary wedge intake and a louvred auxiliary air intake. The twin-shaft, turbo-fan engine has after-turbine flow mixing, a common afterburner, an all-mode variable area jet exhaust nozzle, an independent start and a main electronic control, and a reserve hydromechanical engine mode control system. The high-temperature sections of the engines are made of titanium alloy.