A-720 Skip-2 long-range navigation systems, an ARK-22 radio compass, an MRP-66 radio beacon receiver, an RV-21 Impuls (A-035) radio altimeter, and the DISS-7 Doppler velocity sensor, air signal systems, the IKV-8 inertial attitude indicator inherited from the Su-17M2. The Vyuga target designator pod could be carried in a BA-58 pod under the fuselage, which would enable the use of the Kh-27PS and Kh-58U or E missiles. Some Su-17M4s were fitted with the IT-23M indicator, which would transmit video from the Tubus-2 seeker on the Kh-29T missile to facilitate target acquisition. Su-17M5 (S-56) Proposed upgraded variant with a new fixed wing based on the swing wing at 45 degrees sweep, new avionics, and an AL-31F turbofan. Not built. Su-20 The initial export version of the Su-17M (S-32MK). Su-22M5 A Russian-French upgrade package offered for existing aircraft with modernized cockpit, HOTAS, improved avionic systems, and laser rangefinder replaced by Phazotron/Thomson-CSF radar. Su-22U The S-52U two-seat combat-trainer, export version of the Su-17UM, with a completely re-designed nose housing the tandem cockpits for student and instructor. Gun pods such as the GSh-23 based UPK-23 and SPPU-22 were utilized by the Su-17, Su-20, and Su-22. The SPPU-22 ground attack variant featured 30 degrees of traverse. An experimental version of the Su-20 was built with fixed wings attached to an Su-17M fuselage, in an effort to increase Payload/range performance by eliminating the weight of the wing sweep system. Good results were obtained in flight tests in 1973 but further development was cancelled. Tactical Reconnaissance versions of all variants could be made by fitting the KKR (Kombinirovannyi Konteiner Razvedky – combined reconnaissance pod) on the centre-line hardpoint. In-house OKB designations S-22I The first prototype "Variable-Geometry" Su-7, converted from a production Su-7BM, first flown on 2 August 1966. S-32 The initial production version, dubbed Su-17 by the VVS – Soviet Air Forces. S-32M The Su-17 with the Lyul'ka AL-21F engine and re-structured fuselage plus several smaller modifications, resulting in a greater fuel capacity and more weapons stations. S-32MK The Su-20 export version with revised armament options, and less sophisticated avionics. First flight: 15 December 1972. S-32MK Hybrid Single aircraft (f/n 9500) built with fuselage of S-32MK and fixed wings of Su-7BMK. Offered to customers as cheaper/less complex alternative to Su-20, but no production. S-32M2 The Su-17M with improved flying controls and weapon-aiming equipment. Production carried out from 1975 to 1977 S-32M2K The Su-22 export version of the Su-17M2