NASA 

National Aeronautics and 

Facts

Space Administration 

Dryden Flight Research Center 

P.O. Box 273

Edwards, California 93523 

Voice 661 276-3449 

FAX 661 276-3566 

pao@dfrc.nasa.gov FS-2002-09-062 DFRC 

The Tu-144LL: A Supersonic Flying Laboratory

Project Summary 

The National Aeronautics and Space Administration (NASA) teamed with American and Russian aerospace industries 

over a five-year period in a joint international research program to develop technologies for a proposed future secondgeneration supersonic airliner to be developed in the 21st century. The centerpiece of the project was the Tu-144LL, a 

former first-generation Russian supersonic jetliner that was modified by its developer, Tupolev ANTK, into a flying 

laboratory for supersonic research. 

Using the Tu-144LL to conduct flight experiments allowed researchers to compare full-scale supersonic aircraft flight 

data with results from models in wind tunnels, computer-aided techniques and other flight tests. The flight experiments 

provided unique aerodynamic, structures, acoustics and operating environment data on supersonic passenger aircraft. 

Six flight and two ground experiments were conducted during the program’s first flight phase, which began in June 1996 

and concluded in February 1998 after 19 research flights. A shorter follow-on program involving about seven flights 

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began in September 1998 and concluded in April 1999. All 

flights were conducted in Russia from Tupolev’s facility at 

the Zhukovsky Air Development Center near Moscow. 

Tu-144 Development History 

The Tu-144 was one of only two first-generation supersonic 

transports or SSTs (the other being the Anglo-French Concorde) 

to go into actual production and commercial service. The 

sleek, double-delta-winged craft was the brainchild of famed 

Russian aircraft designer Andrei N. Tupolev, who oversaw 

the development of the Tu-144 as general designer. The 

prototype Tu-144 was first flown on Dec. 31, 1968, about two 

months before the competing Concorde prototype took to the 

air. 

On Nov. 1, 1977, the Russian airline Aeroflot inaugurated 

passenger service with a production model Tu-144 when it 

flew from Moscow to Alma-Ata, Kazakhstan. Limited 

range and other technical problems led to service being 

discontinued in 1978 after only 102 passenger flights. By 

comparison, the Concorde began commercial trans-Atlantic 

service with British Airways and Air France in January 

1976. 

A total of 17 Tu-144s were manufactured, including a 

prototype, two production test versions and 14 production 

aircraft. The latter included five “D” models which were 

fitted with different engines. 

Tu-144LL Modifications 

The aircraft flown in NASA’s research program was a “D” 

model and was the last Tu-144 built. Bearing tail number 

77114, it was constructed in 1981 and had logged a total 

flight time of only 82 hours and 40 minutes, most of that 

for research and test purposes, before being selected for the 

NASA-sponsored program. It was never used in commercial service. 

The aircraft underwent many upgrades and modifications in 

its conversion to the “LL” Flying Laboratory, including the 

installation of more powerful NK-321 augmented-turbofan 

engines that were originally produced for the Tupolev Tu160 Blackjack bomber. 

A new Damien digital data collection system replaced an 

earlier analog system to collect airworthiness data and data 

from the experiments. Thermocouples, pressure sensors, 

microphones and skin friction gauges were placed on the 

Tu-144LL to measure the aerodynamic boundary layer— 

the layer where the air interacts with the surfaces of a 

moving aircraft. It also carried a significant number of 

other research instruments. An emergency crew escape 

system was also installed. 

Flight and Ground Experiments 

Out of 50 experiments originally proposed, project officials 

selected eight, including six flight and two ground engine 

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experiments, for the first phase of flight research. The flight 

experiments included studies on the aircraft’s exterior 

surface, internal structure and engine temperatures, boundary layer airflow, the wing’s ground effect characteristics, 

interior and exterior noise, handling qualities in various 

flight profiles, and in-flight structural flexibility. The two 

ground experiments, completed before the flight experiments began, studied the effect of air inlet structures on the 

airflow entering the engine and the effect on engine performance when supersonic shock waves rapidly change 

position in the engine air inlet. 

The second phase of research flights entailed further study 

of the six flight experiments conducted during the first 

series. Additional instrumentation was installed by Tupolev 

technicians to assist in acquisition and analysis of data. A 

new experiment aimed at measurement of in-flight deflections of the wing and fuselage was conducted, and American-supplied transducers and sensors were installed to 

measure nose boom pressures, angle-of-attack and sideslip 

angles with greater accuracy. In addition, two NASA 

research pilots—Robert Rivers of NASA Langley 

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Research Center, Hampton, Va., and Gordon Fullerton of 

NASA Dryden Flight Research Center, Edwards, Calif.— 

assessed the Tu-144LL’s handling qualities at subsonic and 

supersonic speeds during the first three flights in September 

1998. The follow-on series concluded after four datacollection flights in the spring of 1999. 

Aircraft Specifications 

The modified Tu-144LL Flying Laboratory used for the 

NASA flight research program has essentially the same 

dimensions as the Tu-144D model, although the new 

engines installed for the program give it improved performance. The aircraft has a wingspan of 94 feet, 6 inches, an 

overall length of 215 feet, 6 inches, and a height of 42 feet 

2 inches. Its nose droops up to 12 degrees for better pilot 

visibility on takeoff and landing, and retractable canards 

are extended to give the aircraft better pitch control at low 

airspeeds. Maximum takeoff weight of the Tu-144LL is 

about 410,000 pounds, including a full load of 224,000 

pounds of fuel. 

The newer Kuznetsov NK-321 turbofan engines, rated at 

more than 55,000 pounds thrust in full afterburner, give the 

aircraft a maximum cruising speed above Mach 2.3 (about 

1,550 mph). These engines also give the Tu-144LL a 

greatly improved range of about 3,500 nautical miles 

(4,040 statute miles/6,500 km). 

Before being upgraded to the “LL” configuration, the Tu144D was powered by four Koliesov RD-36-51 turbojets 

which gave it a maximum cruising speed of Mach 2.15 

(2.15 times the speed of sound or approximately 1,450

mph) at 59,000 feet altitude. It had a maximum range of 

less than 2,500 miles and an absolute ceiling of 62,000 feet. 

The Tu-144D was designed to carry up to 140 passengers, 

although earlier models used in actual passenger service 

were configured for only 100 seats. 

The Tu-144LL is constructed mostly of a light aluminum 

alloy. Titanium and stainless steel were used for the leading 

edges, elevons, rudder and under-surface of the rear 

fuselage. 

Technology Commercialization 

Data collected from the flight and ground experiments 

during the NASA-funded Tu-144LL flight research program are being used to develop the technology base for a 

proposed future second-generation American-built supersonic jetliner. Although development of an advanced SST 

is currently on hold, commercial aviation experts estimate a 

market for up to 500 such aircraft could develop by the 

third decade of the 21st century. 

Among the technological goals set for the aircraft is that it 

must be environmentally acceptable in the areas of noise 

generation and pollution control, i.e., the engine exhaust 

must not contribute to the depletion of the ozone layer in 

the stratosphere. At the same time, it must be economically 

viable, that is, be able to carry larger payloads for longer 

distances and at cheaper costs than first-generation SSTs. 

Among the targets are a 300 passenger capacity (three 

times that of first-generation SSTs), a range of 5,000 

nautical miles (twice that of first-generation SSTs), and an 

efficiency which would allow fares to be set at no more 

than 20 percent above subsonic jetliner fares on the same 

routes. 

Project Management 

The Tu-144LL supersonic research program was conducted 

as part of NASA’s High Speed Research (HSR) program, 

managed by NASA Langley Research Center. The Tu144LL project established direct working relationships 

between American and Russian aircraft manufacturers and 

enhanced the relationship between U.S. and Russian 

aeronautical agencies. 

The project was enabled by an agreement signed in June 

1994 by U.S. Vice President Al Gore Jr. and Russian Prime 

Minister Viktor Chernomyrdin. The Langley Research 

Center subsequently contracted with the Boeing Commercial Airplane Group which in turn contracted with the 

Russian aerospace firm for use of the modified Tu-144D 

jetliner to conduct the flight experiments. In addition to 

Boeing, the American industry team for the Tu-144LL 

project included engine manufacturers Pratt & Whitney and 

General Electric. NASA’s Dryden Flight Research Center 

provided instrumentation and data processing support as 

well as management of the actual flight test project. IBP, 

Ltd., London, England, assisted with contract management. 

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