Predictions about the imminent exhaustion of hydrocarbons increasingly appear on the tapes of the world's media. The fact that the recoverable oil reserves come to an end, I can't deny even the optimists. Today special significance is another question – what to do to mankind when the oil will run out? Today, the most traditional answer is that alternative and environmentally friendly sources will not allow humanity to die. This is largely so. What about aviation? American specialists have developed a special jet fuel on the basis of bioethanol.
However, few people today remember that on 15 April 1988 in the USSR flew the world's first passenger liner with a cryogenic engine, to which fuel was liquid hydrogen.
Work on the creation of cryogenic engines are maintained in a number of countries. However, Russia is the most prepared country to build aircraft using cryogenic fuel, because it is in our country for more than twenty years ago made the first flight of creoplan the plane with the engine on liquid hydrogen.
The issue of fuel crisis is not new – it was getting gradually, through a series of regional and global crises. So, back in the mid 70-ies of XX century for the first time publicly talking about not infinity oil reserves. In those same years broke out and the first oil crisis, which forced to reflect on the problem of providing jet fuel for the growing fleet of long-haul passenger aircraft. It was then at the highest state level and it was decided on intensification of works on creation of aviation engines on alternative fuel. The most appropriate economic indicators were biotoplivo – liquefied natural gas and, most importantly, hydrogen.
Academy of Sciences of the USSR was given the task in the shortest possible time in cooperation with leading sectoral research institutes and design bureaus the number of research and development works to study the potential for introduction of hydrogen energy in the national economy. In the aviation industry, this topic is called "Cold".
The initiative to create an experimental aircraft that uses as fuel liquid hydrogen, was made by General designer of OKB A. N. Tupolev Alexei Andreyevich Tupolev. In addition to its main task – working out a new type of fuel – this program allowed simultaneously to drastically improve the environmental situation in the country, and to lay the foundations for the creation of hypersonic and space aviation, which in those years was an absolute global priority.
However, as is often the case, early work showed that the problem is not as simple as initially thought. The subject demanded a much broader and deeper research. Thus, liquid hydrogen is its high specific calorific value three times of hydrocarbon fuel with exceptional environmental purity proved to be extremely promising as a fuel for various engines, especially for projects of hypersonic aircraft, both civilian and military purposes.
In flying laboratory Tu-155 was converted serial Tu-154, number of the state registration – the USSR-85035. For maintenance of aircraft was developed by aviation cryogenic system that allows you to conduct different types of tests with the use of large quantities of cryogenic liquid.
April 15, 1988, the crew of the test pilot V. A. Sevankaev for the first time lifted the car into the sky. In fact, this date can be considered the beginning of the era of cryoplanes in aviation.
All in all the program was made over a hundred flights, including 5 – for liquid hydrogen. At the Tu-155 was used one engine NK-88 (second), running on hydrogen, and two turbofan engine NK-8-2 (first and third). The hydrogen tank was placed in a continuously purged with air (or nitrogen) the rear compartment (from the structural complexities of placement in the wing). Distinctive external feature of this plane – projections of the drainage system on the tail.
Experts note that the created cryogenic engine could be used as fuel and liquefied natural gas. A reworked version of the engine (NC-89) was applied in the project of the Tu-156. According to some, these engines were worked out double for an experienced aerospace plane Tu-2000, which was never implemented.
The main results of the work on "Cold" were:
- formation of groups of specialists in the field of aviation cryogenics in a number of enterprises;
- creation of ground infrastructure for servicing cryogenic aircraft;
- the creation of the complex ground cryogenic test stands.
It is known that in OKB im. A. N. Tupolev in the 70-80-ies of XX century was studied and other projects of aircraft on alternative fuels. There is mention about the projects of Tu-160 and Tu-144 on liquid hydrogen.
The country's leadership highly valued the achievement of "Tupoleva" and all who worked with them in related organizations. 15 participants were awarded prizes of the Government of the Russian Federation, many honored titles and state awards.
As noted by "tupolevs", currently attempts are being made missions using as fuel liquid hydrogen. Often these attempts are issued for the pioneer, although pioneer they were not already more than twenty years ago. As the first in the history of cryogenic aviation will forever remain OKB them. A. N. Tupolev, who created and sustained the world's first aircraft able to use two types of fuel – liquid hydrogen and liquefied natural gas.