of a number of existing Yak-28R aircraft. Yak-28RL Radiation Intelligence aircraft conceived by fitting RR8311-100 air sampling pods, with no other specialist equipment. Modification of a number of existing Yak-28L aircraft. Yak-28PP (Izeliye 28PP) (NATO reporting name – "Brewer-E") Deployed in 1970, it is notable as the first Soviet electronic countermeasures (ECM) aircraft. It was unarmed, with an extensive electronic warfare (EW) suite in the bomb bay and various aerials and dielectric panels for transmitting the jamming signals. Excess heat generated by the jamming equipment was dissipated by heat exchangers under the centre fuselage; it did not include a radome. Produced in the 1970s in unknown numbers. Yak-28VV proposition (vertikahl'nyy vzlyot – vertical take-off) A vertical takeoff and landing project, with two R-27AF-300 lift/cruise engines and four R39P-300 lift engines in the forward fuselage. Yak-28LSh proposition Light attack aircraft project competing with the Ilyushin Il-102 and Sukhoi T-8, eliminated at an early stage. Yak-28P (Izdeliye 40) (NATO reporting name – "Firebar") A dedicated long-range interceptor version, the Yak-28P was developed from 1960 and deployed operationally from 1964. It omitted the internal weapons bay in favor of additional fuselage tanks (its fuel capacity was considerable, limited by weight rather than volume), and added a new 'Oriol-D' interception radar compatible with the R-98 (AA-3 'Anab') air-to-air missile. Late production "upgraded" Yak-28Ps had a longer radome of pure conical shape and enhanced armament. Produced until 1967, with 435 built. Yak-28PM prototype Upgraded Yak-28P with R11AF3-300 engines, flight testing started in 1963 but development abandoned when the R11AF3-300 did not enter production.The re-engined "PM" modification has established a speed record of 2,400 km/h in 1963. Yak-28URP prototype High altitude interceptor prototype using a rocket engine to boost performance during the interception phase. Yak-28-64 prototype Extensively redesigned Yak-28P with Tumansky R-11F2-300 engines moved to the rear fuselage with intakes extending to the cockpit, intended to compete with the Sukhoi Su-15. Performance was very disappointing, being slower than the Yak-28P, and serious aileron reversal issues caused the abandonment of the Yak-28-64. Operators Russian Air Force Soviet Air Force Soviet Anti-Air Defense Military of Turkmenistan Ukrainian Air Force operated 35 aircraft. Specifications (Yak-28P) See also References Notes Bibliography Taylor, John W. R., ed. Jane's All The World's Aircraft 1976–77. London: Macdonald and Jane's, 1976. . External links The Yakovlev Yak-25 & Yak-28 Air Vectors Aero-concept 1950s Soviet bomber aircraft 1960s Soviet fighter aircraft 1960s Soviet military reconnaissance