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Aviation History
1996
1996 - 3347.PDF
AIR TRANSPORT develop new engine mounts and new nacelles. We actually considered using the Tu-160 at one stage, but the -144D was closer to the aerody namic ratio needed, so we stayed with it." The redesign work involved strengthening the wing to take the higher weight and thrust of the new engines; and changes in the fuel, elec trical, control and hydraulics systems. In September 1993, the US-Russia Gore- Chernomyrdin talks included an agreement on the Tu-144 programme, the first major US- Russian aerospace joint programme, and in October that year, Tupolev hosted a large US delegation to lay down the requirements of the flying laboratory. Talks continued on and off until June 1994, when NASA and Tupolev signed a S10 million contract to be funded by the US partners, plus the Russian Government. The joint effort, with US engineers working alongside Russian staff, began in August 1994. The aircraft had been totally dismantled, engines removed and all inspection panels opened; everything was stripped, checked and rebuilt, with the modifications incorporated. The modifications included the installation of Damien V and VI computers to log the data recorded from around 1,800 sensors fitted to measure temperatures and pressures through the airframe and wings. "The sensors added quite some weight to the aircraft," says Pukhov, "but without the passengers and baggage, there was no problem carrying it." FUNDING DELAYS When the Tu-144LL was rolled out on 17 March, it was expected that it would be flown within two months. Funding delays have meant that eight months have now passed, but the first flight took place on 29 November from Zhu- kovsky, with Tupolev test pilot Sergei Borisovin command, and the second on 11 December. The flight-test programme requires 32 flights to be completed in Russia. The first two flights were essentially to ensure that everything works on an aircraft that has not been flown for six years. Over the first two flights, take-off weight was to reach 150-160t, speed MO.85 and alti tude 3.3,OOOft, and controllability and stability, engine restart, emergency hatch operation, and some auxiliaries were to be checked. Over the next seven flights the crew will test a range of parameters at subsonic speeds, including engine stability, fuel consumption, and the effects of the loss of one engine. The tenth flight, again subsonic, requires a maxi mum-range check at a take-off weight of 180t. Two flights will then be used to check longitu dinal and lateral stability in take-off, flight and landing configurations. The supersonic programme begins with the fourteenth flight, when intake settings checks at M1.4, M1.8 and M2.0 are undertaken, with later flights being used to measure settings on acceleration from M0.8 to M max, and on decel eration also; control and stability through the sound barrier up toM1.8; fuel consumption at HISTORY THE TU-144 PROGRAMME was start ed only in 1963, when the Soviet Government had told Tupolev that, al though the equivalent Aerospatiale/ British Aerospace Concorde programme had started earlier, the Soviet aircraft should be the first to be flown—and it was. To speed things up, the design team led by Alexei Tupolev, son of the founder of the bureau, was allowed to draw over 1,000 specialists from other aviation pro grammes. Mikoyan also fitted a new wing shaped like that of the Tu-144 to a MiG- 21, to test aerodynamic qualities. The prototype was completed at Tupolev's design workshop in Moscow in mid-1968. As was usual with Tupolev pro totypes, it was then disassembled and taken by road to the then-secret research airport at Zhukovsky, then re-assembled. This took until October, when ground and engine tests began. The aircraft was ready to fly by mid-December, but bad weather delayed its first flight until 31 December. During testing, changes were made to the wing (in sweep, anhedral, chord and area) while canards were added just aft of the cockpit to improve lift at low speeds. The specifications calling for the ability to carry 120 passengers at Mach 2.35 were met, but the Tu-144's range proved to be only about 3,500km instead of the speci fied more-than-6,500km (3,500nm), how ever, because of the Kuznetsov NK-144's higher-than-expected fuel consumption. This would mean that, on the route from Moscow to Khabarovsk, an intermediate landing would be needed, losing the time savings which justified the programme. Even worse was the loss of the second production aircraft at the 1973 Paris air show. While no report was ever issued on the accident, Tupolev sources maintain The fourth Tu-144 that it was caused by the crew taking emer gency action to avoid hitting a French air force Dassault Mirage whose crew was taking photographs. To solve the engine problem, the Soviet Union ordered the Kolesov design bureau to develop the new Kuznetsov RD-3 6-51A engine for the long-distanceTu-144D, which was flown in November 1974. Although Aeroflot was losing its enthu siasm for the aircraft, crew training began in late 1974, and Moscow-Alma Ata cargo and mail services began in December 1975. Certification was eventually award ed on 1 November, 1977 and, using the short-range NK-144 engines, the ministry of aviation production began services on the Moscow-Alma Ata route. Over the next seven months, 50 return services were flown and 3,200 passengers were car ried. In May 1978 the first production Tu- 144D suffered an electrical fire and was destroyed during an emergency landing. Although Tupolev engineers believed that the cause of the fire was simple to rec tify and eliminate, political support for the Tu-144 was ended by the accident. Two aircraft were kept in service for research-work purposes on a range of pro grammes, including investigating ozone- layer problems, until November 1990. By then, the 16 completed Tu-144s had been flown just 4,1 lOh in 2,556 flights. The last completed Tu-144D at Zhukovsky during the roll-out of the Tu-144L Ml .8-M2.0; service ceiling at a take-off weight of 200t and M2.0 and at levels up to 60,000ft; high-speed control and stability tests and hand ling quality evaluations, plus specific problem situations including rocking pump failure, afterburner checks and cross- fuel-supply feeds in engine failure situations. The last flight will evaluate emergency descents. The 32 test flights are expected to take about nine months. When they have been completed, there may be more work in store for the Tu- 144LL. The Russian parliament has asked the Academy of Sciences to draw up a programme using the Tu-144LL to study and to solve the ozone layer prohlfems; while NASA is studying the idea of bringing it to California to study sonic-boom problems and is also interested in ozone-layer questions. These could well keep the Tu-144LL, and possibly even a second one, busy for the next three to four years. • FLIGHT INTERNATIONAL 18 - 31 December 1996 27
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