Proud of the past, create the future together!

Tu-144

“144” (TU-144). First in the world supersonic passenger production aircraft.


TU-144D production a/c

Successful building in the 50-s of supersonic combat airplanes including heavy ones, created a favorable situation to study possibilities for building supersonic passenger airplanes SST). First SST projects took their origin in the first post-war years when in the USA and in UK some hypothetical projects were proposed which technical approaches were too far from practical realization. In late 50-son both sides of “iron curtain” there appeared first prototypes and consequently production supersonic heavy airplanes of military purpose and substantially straight away on this basis leading world aircraft companies prepared projects of the SSTs of various aerodynamic schematics and arrangements. Comprehensive review of these SST projects revealed that building of effective competitive SST by upgrading of military prototype – is extremely complicated task (in contrast to the process of first jet passenger aircraft building basing on subsonic heavy combat aircraft). First supersonic combat mainly complied with requirements of relatively short supersonic flight. The SST had to ensure cruising flight at speeds corresponding to at least M=2 plus specific task of passenger transportation required significant increase in safety level of all aircraft components provided the aircraft is operated more intensively by increasing supersonic modes of flight. Step by step making analysis of all possible approaches aircraft specialists both in the USSR and in the West came to a firm opinion that economically efficient SST should be designed as a radically new type of aircraft.


Layout of TU-144 prototype with NK-144 engines

 

TUPOLEV DB started SST designing in early 60-s. First technical proposals were mainly based on large-range bombers. Later on when activities started on TU-144 a/c S.Yeger proposed preliminary project of TU-144 powered by NK-144 engines. Besides TUPOLEV DB preliminary study of SST in the USSR was made in DB-23 named after V. Myasishev. In this DB in late 50-s some original SST projects were prepared (M-53, M-55A, M-55B and M-55V).


Assembling of TU-144 production aircraft

Early 60-s were characterized by deployment of practical activities on English-French SST “Concord” (investigation of the subject was started in 1955-1956) with cruising supersonic flight speed more than M=2 and flight range of 6000 – 6500 km carrying 120-140 passengers. Simultaneously leading aircraft USA companies basing on their view of future SST market started working on designing of much greater SST than “Concord” which was intended for transportation of 250-300 passengers at cruising speed up to M=3 for the range of 7000 – 8000 km (projects of Boeing, Lockheed, Douglas).

 


TU-144 a/c assembling

Analysis of conditions of existing of future SST made in the USSR regarding to the level of native aircraft manufacturing and its closest future and also regarding economical potentials of the country and Civil Aircraft Fleet demands, revealed that for the USSR the most preferable was building of the SST which was close to “Concord” by its performance data. In the course of building the Soviet SST a number of scientific tasks were put in front of our aircraft science and industry These tasks have not ever been put in front of our subsonic passenger or military supersonic aviation. first of all to ensure required SST performance data (M=2 flight for the range of up to 6500 km carrying 100-120 passengers in combination with acceptable take-off and landing data) it was necessary to provide significant improvement of aerodynamic cleanness of the aircraft during cruising flights at M=2 –2.2. Under such conditions L/D ration should be increased up to 7.5 – 8.0. It was necessary to solve stability and controllability problems of a heavy aircraft during flights within subsonic, transonic and supersonic envelopes, to elaborate practical methods for trimming aircraft under all said conditions in view of minimization of aerodynamic loss. Durable flight at the speed of M=2 was associated with strength of airframe design at increased temperatures (close to 100-120 o C). We were going to create heat resistant structural material, lubricants, sealant and also to elaborate new types of structures capable for long-term operation under cyclic aerodynamic heating. Very high requirements were established to Powerplant components: it was necessary to build powerful and economically efficient engines capable to operate steadily during supersonic flight. Also it was necessary to solve problems of controlling air intakes operated within wide range of altitudes and speeds by controlling required inlet air flow at possible less aerodynamic loss. The most efficient was to perform durable supersonic cruising flight at high altitudes. Accordingly main and component DB were put in front of the tasks of designing of principles of new air-conditioning systems and later specific components and systems ensuring passengers and crew members with comfortable conditions at high altitudes (up to 20 km) and when durable flights at significant heating of airframe components. We had to design a number of new devices and systems for automatic flight control, precision navigation when performing durable supersonic flight and also automatic landing. Necessity arose to investigate ecological features of the SST operation associated with emission of great amount of engines exhaust gases at high altitudes and their affect upon ozone layer, noise and sound wave affect upon people, animals and buildings, affect of durable flight at high altitudes upon passengers and crew members associated with solar irradiation. When designing the SST it was necessary to take into account particularity of domestic and international air transportation, existing airfields and air traffic control.


TU-144 prototype roll out in Zhukovskiy

All said problems were studied comprehensively with attraction of western practice by TsAGI, TUPOLEV DB, and other DBs involved in the Program on designing of soviet SST. Official basis of the first generation SST (SST-1) building designated as TU-144 was Resolution of Council of Ministers of the USSR, 1963 and Decree of the same year. TUPOLEV DB was given a task to design and build SST with cruise flight speed of 2300-2700 km/h, operational range at supersonic speed with 80-100 passengers on the board was prescribed to be 4000-4500 km; in accelerated version with additional fuel tanks carrying 30-50 passengers – 6000-6500 km/h. Operation from I-st class airfields at normal take-off weight of 120-130 tones. In 1966-1967 we were going to build 5 TU-144 machines (two machines were intended for structural tests). In view of technical complexity of obtaining maximal flight range works were divided into two steps: at the first step operational flight range was to be 4000- 4500 km/; at the second step TU-144 a/c had to reach flight range of 6500 km. By-pass turbofans with reheat chamber was prescribed for the TU-144 a/c. DB named after N. Kuznetsov undertook creation of turbofans for the SST that were designated as NK-144 having take-off thrust of 20000 kgf and sfc equal to 1.35-1.45 kg/kgf h at cruising flight. It should be noted that the TU-144 project progress was mainly effected by a successes of engine manufacturers. This choice was not self-evident. It was more reliable and chipper and allowed flights within more wide range of altitudes and speeds in comparison with simple turbojets. Possibility to have small fuel consumption at cruising speed and consequently – ensurance of required flight range. It was not a surprise both for TUPOLEV specialists and for Ministry of Aircraft Industry. During designing of Myasischev SST there were results showing that it was quite realistic to obtain suitable supersonic flight range if to use engines with sfc not more than 1.2 kg/kgf hour. Prototype of such engine was built in the 60-s in the USSR – it was nonafterburning turbojet “16-17” (take off was 18000 kgf, sfc at cruising flight was 1.15 kg/kgf hour) which was designed in DB-16 named after P.Zubtsov. English and French designers of the “Concorde” chose an intermediate way and selected reheated turbojet Bristol “Olymp” 593 with non-high reheating and with SFC = 1.327 kg/kgf hour at afterburning (afterburning takeoff is 17200 kgf). Unfortunately works on heavy SST at Myasischev DB were terminated. Thus in early 60-s in the USSR development of powerful economically efficient nonafterburning turbofans temporarily was stopped (DB-16 was switched to solid rocket engines. As a result by the beginning of the TU-144 a/c designing the TUPOLEV DB had to undertake a technical risk by selecting NK-144 . In 1964 it was decided to resume works on economically efficient powerful nonafterburning turbojet for SST: in DB-36 under P. Kolesov they started to design RD-36-51 turbojet for TU-144 a/c with maximal take off equal to 20 000 kgf and estimated SFC of 1.23 kg/kgf h at supersonic cruisin.


A.N.Tupolev and A.A.Tupolev with crew of TU-144 prototype after the first flight

Chief Designer and Manager was Alexey Tupolev. Tu-144 a/c conception and future layout was originated under his leadership and with best aviation science specialists involved. Later on the TU-144 a/’c Project was managed by Y. Popov and B. Gantsevskiy. Soon the TU-144 Project became one of main and priority subjects of the DB and of the whole Ministry of Aircraft Industry for the nearest decade.

 

 

 


Takeoff of TU-144 production aircraft

TU-144 aerodynamic layout was defined mainly by long flight range at cruising supersonic speed at required stability and controllability and prescribed take-off and landing characteristics. Basing on promised SFC of the NK-144 at the first step of designing the task was to reach Kmax=7 at cruising supersonic flight. According to economical, technological and weight aspects M=2.2 was assumed. In the course of TU-144 aerodynamic arrangement study several tens of approaches were considered. First “normal” arrangement with horizontal tail. It was rejected since such tail contributed up to 20% to total amount of aircraft drag. “Canard” arrangement was also rejected due destabilizer affect on main wing. Finally they decided in favor of low-wing arrangement – “tailless” a/c with ogival double-delta wing (the wing was defined by two triangle airfoils with strake edge sweep angle of 78o and 55o along rear basic portion) provided with four afterburning turbojets installed under the wing with vertical tail is installed along longitudinal axis and with retractable tricycle landing gear. Airframe structure was mainly made of common aluminum alloys. Wing was defined by symmetrical profiles and had complex twist in two direction: longitudinal and lateral. This resulted in the best flow about the wing at supersonic speed. Furthermore this twist contributed to improvement of longitudinal trimming under said conditions.


Static electricity cones on TU-144 a/c wing

Entire rear edge was provided with four-pieces elevons per each half-wing. The wing has multi-spar structure with powerful skin made of continuous aluminum alloys plates, central wing and elevons were made of titanic alloys. The elevons sections were activated by two irreversible actuators. Rud was deviated by means of irreversible boosters and was defined by two separate sections. Aerodynamic arrangement of he fuselage were chosen in view of obtaining minimal drag under supersonic conditions. Aiming at this the aircraft structure was made more complicated. Characterizing feature of TU-144 a/c became sinkable , well glazed nose fuselage in front of cockpit which provided good view at large take-off and landing angles of attack inherent to the airplanes with wings of small aspect ratio. The nose fuselage could be lowered or hoisted by means of hydraulic drive. When designing the deflectable non-pressurized portion and its components we managed to preserve smooth skin in interfaces between the movable portion and pressurized and the rest fuselage surface. Engine nacelle form was mainly defined by arrangement considerations and requirements to reliable functioning of powerplant. Four turbofans NK-144 were disposed under wing close to each other. Each engine was provided with its own air intake ; two adjacent air intakes were tied together in common unit. Under-wing air intakes were flat and were provided with horizontal ramp.


TU-144 prototype in Zhukovskiy airfield

Under supersonic conditions airflow can be decelerated in three oblique shock waves, in normal terminal shock wave and in subsonic diffuser. Each air intake operated by automatic control system which could change ramp position and by-pass flap depending on NK-144 engine setting. Engine nacelle length was defined by engine size and TsAGI and TsIAM requirements to air intake duct length needed for normal functioning of the engines. It should be noted that opposite to “Concorde” engines design where it was done as a single process, NK-144 engines engine nacelles with air intakes were designed in two mainly independent processes which led to re sizing of engine nacelles and further to many lack of co-ordination in operation of engines and air intake system. Braking system was supposed to be introduced at landing at the expense of reverser; reverser was planned to be installed on two outer engines (reverser system was not developed which resulted in operation of prototype and production machines with drag parachute). Main landing gear were retracted into wing, nose leg was retracted into forward fuselage space between two air intakes. Small wing height required reduction of wheels dimensions. It resulted in using twelve-wheeled bogie with rather small diameters of wheels. Main fuel resource was kept in wing integral fuel tank. Forward integral wing fuel tanks and additional tail integral fuel tank served for aircraft balancing. Main activities on selecting of optimal aerodynamic configuration of TU-144 a/c were headed by G.A.Cheryomukhin, powerplant optimization was performed by B.Voul department. In TU-144 a/c many principle approaches of remote control system. In particular signals of stability and controllability were tried out in longitudinal and azimuth channels. Under certain conditiona said activities made it possible to perform flight at static instability.Saelection of concept of TU-144 a/c contrls system mainly is a desert of G.F. Naboitshikov. L.Rodnianskiy made a substantial contribution to creation and development of this principally new control system. Pilot cockpit was designed according to requirements of up-to-date ergonomics. It was designed for four seats: two forward seats were intended for pilot and co-pilot, flight engineer was seated behind them, the forth seat was intended for engineer – experimentor in the first prototype. Further the flight crew was supposed to be limited by three pilots. Cabin interior arrangement and finishing of TU-144 a/c cabin were state-of-the art level, the most new finishing materials. Flight and navigation equipment was the best of our native avionics: perfect autopilot and airborne computer could maintain heading automatically. Pilots could see in instrument panel display where aircraft was at certain moment and how many kilometers are left to destination point. Approach was performed automatically at any time of a day under severe weather conditions etc. – all these represented a serious break-through for our aviation.


TU-144 prototype being accompanied by analog-aircraft “21-11” performing the first flight

Building of the first prototype of TU-144 (“044”) was started in 1965. Simultaneously the second prototype was being built for static tests. Prototype “044” was initially intended for 98 passengers, later on this number was increased to 120. Correspondingly design take-off weight was increased from 130 tones to 150 tones. The prototype was built at “Opyt” Plant. In 1967 main aircraft components assembly was completed. In late 1967 the “044” prototype was moved to Zhukovskiy where the aircraft was being added with lack parts during all year 1968.

Simultaneously flights of analogs Mig-21I (A-144, “21-11”) were started. Th analog was built in DB named after A.I.Mikoyan. Its wing was similar to the one of “044” prototype from aerodynamic and geometric point of view. In total they built two “21-11” machines. Many test pilots operated these airplanes including those who tested TU-144 a/c in future including E.V.Yelian. The analog-airplane was successfully operated up to 2500 km/h. Records of these flights served as a basis for final correction of TU-144 wing and allowed test pilots to adopt to the aircraft features.

In late 1968 the “044” prototype (side No.68001) was prepared for the first flight. The flight crew was assigned as follows: test pilot E. Yelian , co-pilot – M.Kozlov, leading test engineer V.Benderov and flight engineer Y. Seliverstov. In view of novelty and uncommonness of the new machine the Design Bureau began extraordinary approach: it was first time when prototype passenger aircraft was provided with ejection crew seats. During whole month they performed engines running, rolling, final ground checks of the systems. From the end of December , 1968, the machine was completely ready to perform the first flight. And finally on the last day of 1968 “044” lifted-off in Zhukovskiy for the first time and rapidly climbed. The first flight lasted for 37 minutes. The flight was followed by analog-aircraft “21-11”.


Production TU-144 a/c with NK-144A engines

According to flight crew the aircraft proved to be flexible and easily piloted. A.N.Tupolev, A.A.Tupolev and many others attended the first take-off. The first flight became the vent of world-wide importance and main milestone in history of Russian and International aviation. It was the first flight of Soviet supersonic passenger aircraft – the first “Concord” will lift-off only on 2 March, 1969. 5 June, 1969 the prototype exceeded sonic speed for the first time at the altitude of 11 000 m. By May, 1970 the machine performed flights at speeds of M1.25-1.6 at the altitudes up to 15 000 m. 12 November, 1970 the aircraft “044” performed half-hour flight at speed more than 2000 km/h; at the altitude of 16960 m maximal speed of 2430 km/h. In the course of the tests the aircraft flown beyond USSR boarder several times. In May-June, 1971 “044” aircraft participated Le-Bourget Airshow where it met “Concord” for the first time. The “044” a/c was provided with prototype NK-144 engines with SFC at cruising supersonic mode equal to 2.23 kg/kgf hour. At such SFC during tests TU-144 a/c reached supersonic flight range of 2920 km which was significantly less than required range. Furthermore in the course of tests some design defects: during flight they observed enhanced vibration level and tail fuselage heating from the package of four engines, even titanic structures could not help. Upon completion of test flight program (totally about 150 flights) the “044” machine remained in one copy. Nobody expected more form it. It fulfilled its task to demonstrate that USSR was capable to built supersonic passenger aircraft. It was necessary to move ahead improving the aircraft structure and engines.


TU-144D production a/c

Activities on development of “044” a/c basic structure were performed in two directions: creation of an advanced and efficient non-atferburning turbojet engine of RD-36-51 type and significant improvement of aerodynamics and structure of TU-144 a/c. It had to result in compliance with requirements to flight range of supersonic flight. In 1969 Committee of Council of Ministers of the USSR took a decision about the version of TU-144 a/c with RD-36-51 engines. In parallel it was proposed by Ministry of Aircraft Industry to manufacture six TU-144 a/c provided wit NK-144A with reduced SFC. The TU-144 a/c structure with NK-144A engines was supposed to be significantly upgraded, to change aerodynamics seriously to obtain Kmax more than 8 at supersonic cruising flight. Said upgrading had to ensure fulfillment of the first step requirements to flight range (4000-4500 km). Further the production TU-144 airplanes were supposed to be switched to RD-36-51 engines.

Preproduction upgraded TU-q44 a/c building started at “Opyt” plant in 1968. Estimated supersonic flight range (Cp=2.01) with NK-144 engines had to make 3275 km while with NK-144A engines (Cp=1.91) to exceed 3500 km. Aiming at improvement of the aircraft aerodynamic characteristics at cruising flight M=2.2 wing planform was modified (wing leading edge extension sweep was reduced to 76o while the basic one was increased to 57o), the wing shape became close to “ogee”. In comparison with “044” wing area was increased and more intensive conic twist was introduced for end wing. The most important novelty introduced into wing aerodynamics became modification of mid-section of the wing which provided self-balancing at cruising flight with minimal quality losses in view optimization of flight-load deformation under said condition. Fuselage length was increased intending for 150 passengers, nose portion was improved which also made positive effects on aerodynamics of he aircraft. Opposite to “044” each couple of engines installed in double nacelles with air intakes were spaced. They were removed from lower fuselage and unloaded it from increased heat and vibration loads; modifying lower wing surface at the point of estimated location of air flow pressurization, gap between lower wing surface and upper surface of air intake. All this made it possible to use air flow pressurization before air intake at Kmax more efficiently than in “044” a/c. New arrangement of engine nacelles required landing gear modification: main landing gear legs were disposed under nacelles, they were retracted into the space between air ducts of engines, switched to 8-wheels bogie, nose landing gear retraction arrangement was also modified. The main distinguishing feature of “004” form “044” became introduction of nose multisectional winglet extendable from fuselage at take-off and landing modes which provides required balancing of the aircraft at deflected elevons-flaps. Design improvement, increase of payload and fuel resource resulted in increase of take-off weight of the aircraft which was more than 190 tones (for “044” – 150 tones).


TU-144 passenger cabin

Building of pre-production TU-144 No. 01-1 (side number 77101) was finished in early 1971. I June, 1971 the aircraft performed its maiden flight. According factory tests program the aircraft made 231 flight, duration 338 hours, 55 hours off them – fall on supersonic flights. On this machine aspects of interaction between powerplant and aircraft under various conditions were tried out. 20 September, 1972 the aircraft performed a flight on route Moscow-Tashkent. In this case the route was passed during 1 hour and 50 minutes. Cruising flight speed reached 2500 km/h. Pre-production machine served as a basis for serial production at Voronezh Aircraft Plant.

The first flight of TU-144 a/c No.01-2 (side number 77102) with NK_144A engines was performed 20 March, 1972. According to results of pre-production machine wing aerodynamics was improved and its area was slightly changed. Take-off reached 195 tones. SFC of NK-144A by the moment of operational tests was supposed to reach 1.65-1.67 kg/kgf hour and further – to 1.57 kg/kgf hour. In this case flight range should be increased to 3855-4260 km and 4550 km respectively. In reality in 1977 during TU-144 a/c tests and development with NK-144A Cp=1.81 kg/kgf h was reached at supersonic thrust of 5000 kgf, Cp=1.65 kg/kgf h at take-off afterburning thrust 20000 kgf, Cp=0.92 kg/kgf h at cruising subsonic thrust 3000 kgf and at maximal afterburning transonic thrust 1 1800 kgf.

3 June, 1973 during demonstration flight at Le-Bourget the first production aircraft crashed. The whole flight crew died (test pilot M.V.Kozlov, co-pilot V.M.Molchnov, Deputy Chief Designer V.Benderov, flight engineer A.I.Dralin, navigator G.N.Bazhenov, engineer B .A.Pervukhin. To investigate the crash special Commission was established involving USSR and French experts. According to the investigation French side highlighted that there were no technical failures. The crash was provoked by unfastened crew members, unexpected appearance of “Mirage” aircraft within field of view TU-144 a/c crew, video-camera available in hands of one of the crew members which could jam control stick when it fell. To all appearances at that time this explanation satisfied everybody. Perhaps the most expressive remark was made by E.Yelyan: ”This crash was sad example showing how coincidence of minor negligence also from French air traffic control services resulted in tragedy”.


TU-144D a/c provided with RD-36-51A engines at Moscow Airshow

Production of TU-144 a/c with NK-144A was continued in Voronezh up to 1977. Large amount of flight tests were made on this aircraft and flights with passengers were started. The first flight of TU-144 No.02-1 (side number 77103) was performed 13 December, 1973. Flight and navigation complex NPK-144, power supply system were tried out, the aircraft was tested aborted takeoff, technical flights were performed to various cities of the USSR.

On TU-144 No.02-2 (side number 77104) – the first flight was made 14 June, 1974 – aerodynamics, strength, large angles of attack tests were performed. Aircraft systems and equipment was checked under nonstandard conditions. In 1975 the aircraft flown to Le-Bourget.

TU-144 No.03-1 (side number 77105) was built in 1973 and was modified streight away to TU-144D with RD-36-51A engines.

TU-144 No.04-1 (side number 77106) – the first flight was performed 4 March, 1975 – was used to assess effectiveness of air-conditioning sytem/ Some problems on fuel system were solved on this aircraft. 26 December, 1975 this machine performed the first operational flight on the route Moscow-Alma-Ata. The aircraft carried goods, mail. The flights were made at the altitude of 18000 m at the speed of 2200 km/h. Currently TU-144 No. 04-1 is demonstrated in Monino Museum.


Routes of TU-144 supersonic passenger aircraft

On TU-144 No.04-2 (side No. 77108) – the first flight was performed 12 December, 1975 – development works were made on navigation system, flight-director approach, sub-autothrottle. TU-144 No.05-1 (side number 77107) – the first flight was performed 20 August, 1975 – after factory tests and special tests in 1977 was submitted as complex subject for joint government testing. According results of said tests it was noted that flight performance data of the aircraft except to operational range of fight with prescribed passenger number and takeoff weight complied with requirements to TU-144 a/c (when testing operational flight range reached 3080 km at takeoff weight of 195 tones and payload equal to 15 tone and at payload of 7 tone – flight rage was3600 km. It was highlighted that the range of 4000-4500 km at payload of 14-15 tones could not be realize on TU-144 with NK-144A and it was noted that such range could be reached with RD-36-51A engines.


TU-144 production a/c

Upon joint tests completion the decision was taken on beginning of passenger transportation on TU-144 a/c with NK-144A engines. TU-144 No. 05-2 (side number 77109) and TU-144 No. 06-1 (side number 77110) were used for regular passenger transportation on Moscow-Alma-Ata route. TU-144 a/c made his first passenger flight 1 November, 1977. Flights for range of 3260 km at the altitude of 16000-17000 m at the speed of 2000 km/h were performed once a week; number of passengers did not exceed 80 persons. Before the moment of termination of regular operation with passengers inn May, 1978 Aeroflot crews made 55 flights on TU-144 a/c totally carried 3284 passengers. TU-144 with NK-144A became the first USSR passenger a/c which was granted with national airworthiness certificate for safety of passenger transportation.

As it was previously noted activities on alternative RD-36-51 engines for TU-144 a/c started in 1964. Flight range at takeoff weight of 150 tones with 150 passengers on board was stipulated as 4500 km, while with 120 passengers and at takeoff weight of 180 tones – 6500 km. Modification of TU-144 /c with new engines was designated as TU-144D (“004D”). By the middle of the 70-s the RD-36-51 engine became real. The first RD-36-51A engines had takeoff weight of 20000 kgf, cruising thrust of 5100 kgf and SFC at cruising supersonic flight equal to 1.26 kg/kgf h. Lter it was supposed to have takeoff weight of 2 1000 kgf and cruising SFC not more than 1.23 kg/kgf h (in future it could be 23000 – 24000 kgf at takeoff and 5400 kgf at cruising flight).

The first TU-144 a/c provided with RD-36-51 engines was the aircraft No.03-1. Before mid-1976 a new powerplant was developed on this machine. 5 June, 1976 the aircraft performed its large range flight for the distance of 6200 km at payload of 5 tones. This flight confirmed realizability and perspecrtiveness of continuation of works on TU-144D a/c.


TU-144LL Flying Laboratory in Zhukovskiy airfield

In late 70-s Voronezh plant began serial production of TU-144D. The Tu-144 No.06-2 (side number 77111) was the first production aircraft. The first flight was performed 27 April, 1978. The aircraft started joint testing but 23 May, 1978 it crashed near Yegorievsk. The reason for the crash was breakage of fuel line in engine compartment. The aircraft was piloted by test pilot Popov, co-pilot was Yelyan. The flight crew managed to performed forced landing with retracted landing gear. During the landing Yelyan was wounded and two test engineers were killed. This crash was a direct reason to suspend TU-144 operation with passenger and later on to complete termination of such flights. Four machines more were produced and developed – TU-144 №/№ 07-1, 08-1, 08-2 and 09-1. The first two machines were subject to joint government tests which were finalized in mid-80s. Basing on results of said tests TU-144D was recommended to be operated with passengers as well as TU-144 a/c with NK-144A. The aircraft was given airworthiness certificate but was not operated. The program was cut down. The last production machine TU-144 D No.09-2 was not demanded and stood for a long time on Voronezh airfield. Apart those mentioned machines several TU-144 airframes were built to be used in structural tests. TU-144D a/c takeoff weight exceeded 200 tones, during joint government tests supersonic range was reached equal to 5330 km at payload of 15 tones, and with 11-13 tones – the range if 5500-5700 km, and with payload of 7 tones – the range of 6200 km all these with fuel reserve of 10 tones. In the 80-s some of built TU-144 aircraft were used as flying laboratories for various test programs to build advanced supersonic heavy aircraft including the programs of further SST development. In July, 1983 on one of TU-144Ds the flight crew headed by test pilot S.Agapov (co-pilot B.Veremey) established 13 world records of flight speed flight altitude with different cargo ( the machine was designated as “101”). In the 70-s there were projects for further modernization of TU-144 a/c. Practice of development, test and initial operation of TU-144 a/c with NK-144A engines showed that only minimum program could be provided – operation on airlines as long as 4000 km. The beginning of works on TU-144 with RD-36-51 engines showed that TU-144 a/c is capable to reach demanded range and has further margins for modernization. First of all they refused from unification of the structure regarding powerplant. By review of airframe structure, aircraft systems and equipment fuel load ratio was supposed to be increased. The new project was assigned as TU-144DA. Initial study have revealed that there were possibility to increase fuel reserve up to 125 tones (instead of 90-95 tones on TU-144D) at takeoff weight of 235 tones, in this case wing area should be increased up to 544 sq.m (instead of 507 sq.m on TU-144D). Powerplant was moved to “61” type engines with thrust reverser (development of RD-36-51 A engine) with SFC=1.23 kgf/kg h at cruising flight and maximal takeoff thrust of 21 000 kgf. Amount of passengers reached to 130-160 persons, designed operational flight range with normal payload was increased up to 7000-7500 km. Works on TU-144DA were not further developed because of cutting down of entire TU-144 program. However works done on the project were used in investigations for SST-2 (TU-244) which started.


TU-144LL Flying Laboratory during flights performed in USA

It is interesting to compare destinies of TU-144 and “Concord” – the machines that are close by purposes, design approaches and time of building. First of all it should be noted that “Concord” was designed mainly for supersonic flights over uninhabited ocean spaces (main purpose – flights between Europe and America overseas). It was the reason for selecting maller altitudes of crusing supersonic flight which resulted in smaller wing area, smaller takeoff weight, smaller demanded cruising thrust of the powerplant and SFC. TU-144 had to flight mainly over land which lead to large flight altitudes and respectively increase of parameters and demanded thrust of the powerplant. It should be added that the engines were less perfect (by specific parameters the engines of TU-144 a/c were brought close to “Olympus” only in their last modification). All these negative initial data were compensated in the course of development of the project by high aerodynamic cleanness of TU-144 which was achieved by making the design more complicated and by lowering maintainability of the aircraft. Quantity of production TU-144s and “Concord” was approximately the same. But opposite to TU-144 a/c the English-French SST were in operation substantially till early 90-s. In 1986 ticket price for London-New-York flight made 2745 USD. It is affordable only for very prosperous people for whom formulae “times is money” is the main credo. There are such people in West and for them flights by “Concord” are natural saving of time and money. It is confirmed by total flying time of “Concord” in 1989 equal to 325 000 hours. Thus we can consider “Concord” program more commercial and prestigious to some extent in comparison with Americans. In the USSR there were no people for whom time could turn to money therefore the natural market of services which could be satisfied by TU-144s just did not exist. So the aircraft was notoriously unprofitable. Thus from one hand – heroic efforts of Tupolev DB and other aviation organizations on TU-144 a/c development and from the other hand – initial non-professional enthusiasm followed by hamper from Aeroflot side. Therefore in early 80-s when future economic and political crisis became evident in the USSR and Soviet government started money saving policy the TU-144 a/c Program was one of the forst which was affected. Tu-144 a/c building and development became the largest and the most complicated program in history of Soviet aircraft industry. As a result of long term activities it was possible to build aerial vehicle of world level class not being inferior to any western production aircraft of such class.


TU-144 LL Flying Laboratory landing

While active works on Tu-144 were substantially closed in the middle of the 80-s te direction of activities was realized in our DB in creation of SST-2 – TU-244 a/c. Within SST-2 activities one of TU-144D a/c was re-equipped into flying laboratory TU-144LL “Moscow” (4xNK-321) which made several tens of experimental flights within joint program on building in future economically and ecologically perfect supersonic passenger aircraft of the 21 century.

 

 


TU-144LL Flying Laboratory

Main performance data of production SST TU-144D (according test results)