“Tupolev” PSC elaborated Cryogenic Aircraft Manufacturing Program. On the first phase of this Program TU-156 a/c was built.
Cargo-passenger TU-156 a/c was designed for optimization of airborne cryogenic fuel system during long-term operation and its certification and also for optimization of ground infra-structure. Cryogenic components of the aircraft will be installed on consequent serial Tupolev’s cryogenic aircraft.
The aircraft uses two fuels: aviation kerosene and liquefied natural gas which makes it possible to operate the aircraft from usual airfields and from airfields provided with LNG fueling systems. Use of two fuels improves flight safety level significantly.
TU-156 a/c is capable to carry 14 t of payload for distance 2600 km using LNG and for distance of 3300 km using LNG and kerosene. In rear portion of passenger cabin there is a ventilated compartment to receive a main cryogenic tank of 13 t capacity. Nose baggage compartment is provided with ventilated bay wherein trim cryogenic fuel tank is installed composed of two horizontal communicating vessels capable to receive 3.8 tones of LNG.
Substantially all technical publication and records have been issued for TU-156 a/c. NK-89 prototype engine and a number of other cryogenic components have been manufactured and are being tested on benches.
To support activities on TU-156 a/c manufacturing a ground cryogenic power plant rig is now being prepared. On the basis of certified mid-range passenger TU-204 a/c powered by PS-90A engines a mid-range TU-204K a/c powered by PS-92 engines is currently under development. Kerosene is located in wing fuel tanks, LNG tanks are disposed on fuselage within fairing which shape is of minimum aerodynamic drag. TU-204K a/c fuel efficiency makes 19.6 g/pass, km. This aircraft is capable to carry 210 passengers for distance of 5200 km. The aircraft tanks can receive 22.5 t of LNG and 5.5 t of kerosene as fuel reserve. Being developed to the level of technical proposals TU-204K uses main elements of cryogenic system installed on TU-156 a/c.
Works have been launched on manufacturing a new regional cargo/passenger TU-136 a/c powered by two TB7-117SF engines which has optimal layout in view of LNG properties. This aircraft is intended for passenger and cargo transportation. It can be operated from airfields of any class including unpaved ones. It will be operated on routes that connect regional centers of Russia and for cargo/passenger transportation for servicing centers of mineral industry and also to function as flying laboratory for inspection of gas lines in Northern areas and in Siberia. After being certified the aircraft can be used by foreign airlines in the countries with developed infra-structures of natural gas consumers.
This aircraft having takeoff weight of 20 t will carry 53 passengers and up to 5 t of cargo for 2200 km at the speed of 550 km/h and at the altitude of about 72 km. Fuel efficiency (about 20 g/pass, km) corresponds to that of the best aircraft in the world of this class while use of LNG will allow to cut down direct operational expenses by near 30%.
The aircraft was designed in view of special properties of cryogenic fuel. It is of biplane aerodynamic configuration logically interfaced with cryogenic fuel tanks. Structure of the aircraft was made with maximal wing and fuselage load relief.
Cryogenic fuel tanks receiving 3680 kg of LNG are located in two nacelles installed behind power plant. Alignment of tank mid-section with engine nacelle mid-section and also supporting pylons agreement with general aerodynamic configuration made it possible to locate cryogenic fuel tank out of fuselage substantially without increasing aerodynamic drag and wing force. Short cryogenic paths are of small weight and do not require superheat insulation. Power plant spaced from passenger cabin increases passenger and crew members safety significantly and facilitates its experimental optimization. Kerosene is filled in wing tanks as in ordinary aircraft.
TU-330 transport a/c powered by LNG NK-94 engine is now under development. The aircraft is designed to carry military and civil cargo of 35 t weight. Aviation kerosene is located in wing fuel tanks, tanks with LNG are disposed on upper fuselage within fairing which shape is of minimal aerodynamic drag and receive 22.6 t of LNG. Engine NK-94 for this aircraft is developed by “SNTK named after N.Kuznetsov” PSC. It represents a cryogenic version of NK-93. Landing on unpaved airfield is provided.
Currently the aircraft has been developed to the level of technical proposals. The aircraft includes all main elements of cryogenic system installed on TU-156 a/c and can use both LNG and kerosene.
Design works have started to build on the basis of TU-334 a/c a short-range passenger TU-334K a/c powered by BR-710C engines. It will carry 102 passengers for the distance up to 2000 km at the altitude up to 10.6 km. The aircraft is fuelled with 7 t of LNG and 2 t of kerosene as fuel reserve. Main elements of cryogenic system can be taken from TU-156 a/c.