|
Vesti u vezi motora. Izgleda da i Rusi planiraju da urade 2d sistem kao kod F-22 samo sa gubitkom od 2 do 3%:
Citat:The PAK FA lifted into the air for the first time within the framework of factory acceptance tests on 29 January of this year. The aircraft's stability and control and the operation of its primary systems were evaluated during this stage. One of the most important components of these flights was testing the functioning of the new engine. Despite the fact that the engine for the PAK FA repeats the design of the well known AL-31F, it consists of 80 percent new components. These are the low pressure compressor, combustion chamber, turbine, vectoring nozzle that tilts to an angle of 30 degrees, high pressure compressor, digital automatic control system with elements of distributed parameters and a plasma ignition system. As the general designer of the A.M. Lyul'ka Scientific and Technical Center, Evgeniy Marchukov, responsible for creation of the engine for the PAK FA, said at the Dvigateli-2010 ((Engines-2010)) exhibition, a number of measures were undertaken to increase reliability and service lift of this turbofan engine ((TRDD)). It was necessary, inasmuch as the engine is more stressed and has a higher thermal regime.
The plasma ignition system is a novelty for Russian engine construction. Up to now, oxygen injection was used in all ignition systems for boosting altitude capability and the possibility of starting the turbofan engine at altitude. It required the presence of a whole oxygen system on board and the corresponding infrastructure at the airfield. The task was assigned in the creation of the PAK FA to provide engine start without oxygen. The plasma ignition system has been installed in the main combustion chamber and afterburner. According to Evgeniy Marchukov, the know-how was laid in the injector with the plasma system itself: a plasma arch is arranged in it simultaneously with the fuel ((KEROSIN)) supply. Very serious know-how also has been embodied in the ignition components themselves, where it is necessary to supply very high voltage at the same time.
A full authority digital control system also has been used in a domestic airplane for the first time. The hydraulic components are only actuating. As Evgeniy Marchukov noted, the exception is one reserve centrifugal governor which allows returning to base under reduced power conditions during complete malfunction of all electronics, for example as the result of the impact of a nuclear explosion. The digital automatic control system is very mobile and flexible. If earlier, with analogue control, 2 - 3 months passed to change the algorithm of the engine control, today this operation takes several minutes, and sometimes the turbofan engine doesn't even have to be stopped. That is, as the general designer of the A.M. Lyul'ka Scientific and Technical Center noted, checkout and final adjustment of the engine proceeds much faster. It, for its own part, leads to shortening of the time for testing the new airplane.
The first stage engine for the PAK FA was built in a fully traditional design. It, in particular, is deprived of such a characteristic element as the two-dimensional nozzle that the competitor to our aircraft, the F-22, has. However, according to Evgeniy Marchukov, work in the area of exhaust system is underway. Development of the two-dimensional nozzle and reverse thrust ((REVERS)) is at the stage of publishing the engineering documentation.
From the point of view of gas dynamics, the two-dimensional nozzle has continuous deficiencies, inasmuch as during its creation it is necessary to change from a circular section (the engine) to a two-dimensional. Loss of thrust at the same time may be 5 - 7 percent. There is only one advantage - provision of a low heat signature ((TEPLOVAYA NEZAMETNOSTI)) owing to blanking the turbine with the two-dimensional blades. This mode is of restricted use: It is turned on for 5 - 10 minutes to overcome an enemy's air defense system. Such losses are allowed for resolution of this task. But NPO Saturn designers are trying to minimize the losses to 2 - 3 percent.
This ground work must be used during creation of the second stage fifth generation engine…
Source: 27.04.10, Voenno-Promyshlennyy Kur'er, Correspondent: Ivan Karev
|
.
.
