only passenger jets ever fitted with ejection seats, albeit only for the crew and not the passengers. Engines SSTs for M2.2 had been designed in the Soviet Union before Tupolev was tasked with developing one. Design studies for the Myasishchev SST had shown that a cruise specific fuel consumption (SFC) of not more than 1.2 kg/kgp hr would be required. The only engine available in time with the required thrust and suitable for testing and perfecting the aircraft was the afterburning Kuznetsov NK-144 turbofan with a cruise SFC of 1.58 kg/kgp hr. Development of an alternative engine to meet the SFC requirement, a non-afterburning turbojet, the Kolesov RD-36-51A, began in 1964. It took a long time for this engine to achieve acceptable SFC and reliability. In the meantime the NK-144 high SFC gave a limited range of about , far less than Concorde. A maximum speed of (Mach 2.29) was reached with the afterburner. Afterburners were added to Concorde to meet its take-off thrust requirement and were not necessary for supersonic cruise; the Tu-144 used maximum afterburner for take-off and minimum for cruise. The Tu-144S, of which nine were produced, was fitted with the Kuznetsov NK-144A turbofan to address lack of take-off thrust and surge margin. SFC at M2.0 was 1.81 kg/kgp hr. A further improvement, the NK-144V, achieved the required SFC, but too late to influence the decision to use the Kolesov RD-36-51. The Tu-144D, of which five were produced (plus one uncompleted), was powered by the Kolesov RD-36-51 turbojet with an SFC of 1.22 kg/kgp hr. The range with full payload increased to 5,330 km compared to 6,470 km for Concorde. Plans for an aircraft with a range in excess of range were never implemented. The engine intakes had variable intake ramps and bypass flaps with positions controlled automatically to suit the engine airflow. They were very long to help prevent surging; twice as long as those on Concorde. Jean Rech (Sud Aviation) states the need for excessive length was based on the misconception that length was required to attenuate intake distortion. The intakes were to be shortened by 10 feet on the projected Tu-144M. The Kolesov RD-36-51 had an unusual variable con-di nozzle for the nozzle pressure ratios at supersonic speeds. Without an afterburner there was no variable nozzle already available. A translating plug nozzle was used. Production Sixteen airworthy Tu-144 airplanes were built: the prototype Tu-144,