Editing Tupolev Tu-144 (section)

===Engines===
[[File:Tupolev Tu-144 AN0521445.jpg|thumb|Afterburning nozzles on the Kuznetsov turbofan.]]
[[File:Tupolev Tu-144 at the MAKS-2013 (05).jpg|thumb|Plug nozzles on the non-afterburning Kolesov turbojet.]]

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 [[Thrust specific fuel consumption|specific fuel consumption]] (SFC) of not more than 1.2&nbsp;kg/kgp hr would be required.<ref name="tupolev.ru"/> 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&nbsp;kg/kgp hr. Development of an alternative engine to meet the SFC requirement, a non-afterburning turbojet, the [[Kolesov RD-36-51]]A, began in 1964.<ref name="tupolev.ru" /> It took a long time for this engine to achieve acceptable SFC and reliability.<ref name="GordonKomissarovRigmant2015" />{{rp|page=42}} In the meantime the NK-144 high SFC gave a limited [[range (aeronautics)|range]] of about {{convert|2500|km|mi nmi|abbr=on|lk=out}}, far less than Concorde. A maximum speed of {{convert|2443|km/h|mph kn|abbr=on}} (Mach 2.35) was reached with afterburning.<ref name="GordonKomissarovRigmant2015" /> Afterburners were added to Concorde to meet its take-off thrust requirement<ref>Not Much of an Engineer, Sir Stanley Hooker, Airlife Publishing 2002, {{ISBN|978-1853102851}}, p. 153</ref> and were not necessary for supersonic cruise; the Tu-144 used maximum afterburner for take-off and minimum for cruise.<ref name="GordonKomissarovRigmant2015" />{{rp|page=110}}

The '''Tu-144S''', of which nine were produced, was fitted with the [[Kuznetsov NK-144]]A [[turbofan]] to address lack of take-off thrust and surge margin. SFC at M2.0 was 1.81&nbsp;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]].<ref name="GordonKomissarovRigmant2015" />{{rp|page=135}}

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&nbsp;kg/kgp hr. The range with full payload increased to 5,330&nbsp;km compared to 6,470&nbsp;km for Concorde.<ref name="GordonKomissarovRigmant2015" />{{rp|page=248}} Plans for an aircraft with a range in excess of {{convert|7000|km|mi nmi|abbr=on}} range were never implemented.<ref name="tupolev.ru" />

The engine intakes had variable [[intake ramp]]s and bypass flaps with positions controlled automatically to suit the engine airflow.<ref name="tupolev.ru"/> They were very long to help prevent surging;<ref name="GordonKomissarovRigmant2015" />{{rp|page=131}} 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.<ref name="Owen2002">{{cite book |editor1-last=Owen |editor1-first=Kenneth |title=Concorde |date=2002 |publisher=Institute of Contemporary British History |location=London |isbn=0-9523210-7-6 |url=https://www.kcl.ac.uk/sspp/assets/icbh-witness/concorde.pdf |page=90 |archive-url=https://web.archive.org/web/20230531031823/https://www.kcl.ac.uk/sspp/assets/icbh-witness/concorde.pdf |archive-date=31 May 2023 |url-status=live }}</ref> The intakes were to be shortened by 10 feet on the projected '''Tu-144M'''.<ref name="GordonKomissarovRigmant2015" />{{rp|page=178}}

The [[Kolesov RD-36-51]] had an unusual translating plug nozzle as an alternative to a variable con-di nozzle, either of which give the variable area ratio required for the range of nozzle pressures which come from low inlet ram at low speeds to high at Mach 2. A plug nozzle was studied for [[Concorde]] but rejected as it was not certain that it could be cooled adequately during afterburner operation.<ref>https://arc.aiaa.org/doi/book/10.2514/4.868122, p.6-1</ref> The RD-36-51 had no afterburner.