Sapfir-23 was designed by a team under Chief Designer Kunyavsky
for the MiG-23 fighter. A purely air-to-air design, it was the first
radar for a frontal fighter designed to allow BVR engagements. It
used semiconductor technology rather than vacuum tubes and a method
of external coherence in the mode "SDTs" (moving target selection)
to detect aircraft flying below the host aircraft. This had
limitations- it could only detect targets in the duration between
successive pulses, and had multiple "blind" velocities in multiples
of its PRF. It used an analogue AVM-23 computer, and a
twist-cassegrain antenna. Some sources indicate that early versions
could only detect closing targets. The incorporation of an IRST into
the MiG-23 may therefore have been intended give a pursuit
engagement capability.
Sapfir-23L was the radar of the
initial production MiG-23 (1970-71).
Sapfir-23D was the full standard
radar and the first with limited lookdown capability. Search range
was 55km against a closing Tu-16 sized target, 45km against a
MiG-21. Tracking range was about 35km. Fitted to production MiG-23M.
Lots of problems were encountered in service, as it required expert
tuning and high quality maintenance. It wasn't uncommon for the
detection range to vary 10 times from one set to the next. Weight
about 500kg.
Sapfir-23D-Sh was improved with
better discrimination of low flying targets and improved ECCM.
Fitted to later production MiG-23M, older MiG-23M were upgraded to
this standard.
Sapfir-23E was fitted to MiG-23MF
export variants. Based on Sapfir-23D with minor differences.
Sapfir-23ML
Radar
Sapfir-23ML was
initially designed by G. M. Kunyavsky in the early-to-mid seventies,
completed by Yury Kirpichev and introduced in 1976 as a major update
to the Sapfir-23, after early service experience showed various
deficiencies in the original radar. As part of a crash upgrade
program, the radar was thoroughly modernised, increasing ECM
resistance. The Sapfir-23ML's weight (around 350kg) was less than
the original Sapfir-23, which helped improve the MiG-23's agility.
Search range against a fighter was 55km in look-up mode, 20km in
look-down mode. Against a bomber sized target, the detection range
increased to 80km and 25km in look-up and look-down modes
repectively.
Sapfir-23ML-2 was a variant designed
for the MiG-29A, a cut-down MiG-29 intended to use existing
technology to achieve IOC by 1979. Designed by Yuriy Figurovsky, it
was a repackaged and slightly improved version of the MiG-23's
radar. Difficulties in fitting it into the MiG-29 were overcome by
enlarging the wing roots, but it was abandoned in 1976 along with
the MiG-29A. All Phazotron's efforts were redirected to the urgent
task of developing the Sapfir-25 radar.
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