Виноват, что не совсем в тему, и что не по-русски (сил моих тигриных нет больше). Но кто захочет, тот прочитает:
JF-17 "Гром" - дорога к эксплуатационной зрелости
Two years of presence on the world's biggest air shows brought it a reputation of a well balanced aircraft. It's performance are solid. Not in the top five but within third generation standards. Sensors and weapons are too and it's two to three times cheaper than the closest competition, the US F-16 Fighting Falcon and the Russian MiG-29. But, did the JF-17 reach the level of operational maturity to be entrusted with the defense of the country or everything just ends with a nice air show flying? In search for answers Tomislav Mesarić goes to Airshow China held from 13th to 18th of November 2012 in Zhuhai, PRC where he talked to the only people who can testify to that – the pilots and the technicians of the Pakistan Air Force.
When the JF-17 debuted in front of the world aviation audience at Farnborough air show in 2010, Pakistan Air Force had only one squadron with 20 aircraft. Conversion training syllabus has just been approved and the only weapons the aircraft could carry were the general purpose bombs and the short range PL-5EII missiles. But, the things have changed now. “Now we have two JF-17 squadrons: the 16th squadron, the 'Black Panthers' and the 26th squadron, the 'Black Spiders'. The 16th is a fully operational squadron while the 26th has two roles: conversion and operational training. We are about to raise the third squadron but we still didn't decide which one will that be. We have around 40 JF-17's flying at the moment with a last few from Block 1 in the final stages of the assembly”, said Air Commodore Khalid Mehmood, the JF-17 program deputy director.
In Pakistan, the JF-17 is a matter of national pride. When the program started, in the late 90s of the last century, Pakistan was under sanctions for of its nuclear weapons development program. Its economy was in dire straits and its air force without the spare parts for the F-16s, the only modern fighters in its inventory. At the same time it´s biggest rival India started recording unprecedented levels of economic growth and initiated one of the most comprehensive air force modernization programs in its history. Abandoned by the west, Pakistan couldn’t do nothing else but turn to China. Even thou at that time China still didn’t have modern indigenous fighter design its Chengdu Aircraft Industry Corporation (CAC) had something that could be useful to Pakistan Air Force. It was the FC-1 Xiaolong, a light fighter in concept very similar to the Northrop’s F-5G Tiger Shark. Preoccupied with the development of the more advanced J-10 Chinese Air Force wasn’t showing a particular interest for it so CAC was looking for a new partner. For Pakistan Air Force it was the opportunity not to be missed and very soon deal for co-development was signed. It was a good deal because for only half a billion US dollars (an equivalent to a squadron of modern western fourth generation fighters) Pakistan Air Force not only got a 50% share in the production of components and the complete final assembly line but it got a chance to fully adapt the aircraft to its requirements. “Our pilots and engineers are responsible for 90% of the JF-17's system architecture and cockpit design. Their knowledge and experience was used in the design of the HOTAS functionalities, switching layout and displays layout. They where the ones who decided where a particular information will be presented on the displays and how will the display setup change according to the mission scenario”, said Air Commodore Khalid.
Although Pakistan Air Force became one of the first foreign users of the F-16, the JF-17’s cockpit much more resembles one other aircraft – the Swedish Gripen. Namely, at one point Pakistan Air Force seriously considered buying the Gripen so a team of pilots and engineers was sent to Sweden to thoroughly test it. “The Gripen was a great inspiration when we started with the development of the JF-17”, said Group Captain Chaudhry Ahsan Rafiq from the JF-17 program office. Unsurprisingly, three big 8x6 inch color multifunction displays dominate its cockpit and a small number of switches implies there is a solid level of automation in the systems as well. The simbology itself, however, looks like it is coming from the F-16. “Why change something if it works”, said one of the Pakistan Air Force pilots who wanted to stay anonymous for protocolary reasons at the Airshow China. Although he was obviously coming from the F-16 community keeping the same simbology across the fighter fleet significantly eases and thus lowers the cost of training be it for young pilots coming from the academy or more experienced ones going trough the conversion.
In addition to the advanced men-machine interface another feature that separates the JF-17 from second generation fighters is the hybrid flight control system. Namely, the mechanical flight control systems found in second generation fighters, the ones the JF-17 was made to replace, don't offer any kind of protections so pilots are reluctant to use their full aerodynamic potential by flying close to the edge of the envelope. Modern, fully electronic flight control systems offer all kind of protections but they don't come cheap or at least they didn't when the development of the JF-17 started. "The cost control was a priority from the beginning so a much simpler and thus cheaper hybrid flight control system was chosen for the JF-17. In comparison to modern electronic flight control systems it has only one electronic channel, one for pitch. The other two, for bank and yaw are mechanical. It was a minimum requirement to have the angle of attack and the G forces, the two most important flight parameters in maneuvering flight, under the control of a computer. However, technology advanced so now we can offer a fully digital flight control system which is only 10% more expensive than the current hybrid one. It's on the drawing board at the moment but if some prospective customer wants it we can have it certified in two years time”, said Zhu Zeng, a CAC representative at the Airshow China.
Nevertheless, as simple as it is, the hybrid flight control system is still a huge improvement over the mechanical systems. “By knowing the computer will not allow me to exceed the angle of attack and G force limits, 26 degrees or 8 Gs, which ever comes first, I can fly this aircraft much more aggressively”, said one of the Pakistan Air Force JF-17 pilots who just converted from the F-7 (Chinese copy of the venerable MiG-21).
Considering a long time relationship between Russian and Chinese aviation industry it is no surprise that the engine chosen for the JF-17 is the Russian Klimov RD-93. As an adaptation of the RD-33 turbofan from the MiG-29 it lags behind its western counterparts in terms of fuel consumption and time between overhaul (TBO) but its Soviet origin gives it an excellent reputation when it comes to “less than ideal” infrastructure of the Third World. “We have flown 7000 hours with the engine and we didn't have any problems. It’s a very robust engine. It doesn't have a FADEC but it has a form of electronic control so it's completely care free in operation”, said Air Commodore Khalid. A further testament to its reliability comes from the “hot & high” trials conducted from an airfield at 7000 ft above mean sea level and under ambient temperatures of between 25 and 30 degrees C. According to a report the JF-17 took off and landed in combat configurations under such conditions.
To further reduce the weight and complexity of the JF-17 Chinese engineers also found a way to match the RD-93 engine with a novel inlet design called the Divertless Supersonic Inlet (DSI). In comparison to a “traditional” inlet design the DSI doesn't have any moving parts so it’s very light and easy to maintain. For it’s primary function, which is to slow down the airstream, it solely relies on the aerodynamic hump placed at its mouth. Conveniently, this hump also hides the face of the engines‘s compressor thereby further reducing already low radar signature of the JF-17 (low radar signature is an inherent feature of a light fighter).
In comparison to the Indian Tejas the JF-17 wasn't conceived with the same level of self reliance in mind. But, when it comes to the integration of new weapons it provides Pakistan Air Force with lots of flexibility. “We have a complete source code for the flight control system and for the weapons computer. We can buy any weapon on the free market and integrate it on the JF-17 on our own and in country. We have a team of flight test engineers and pilots who form the flight test group as a separate unit so the whole process is done by Pakistan Air Force”, said Air Commodore Khalid.
Further adding to the JF-17‘s flexibility is the 1760 interface on its hard-points. Since it's a digital interface the 1760 eliminates the need to rewire the aircraft every time a new weapon is added.
Since the short range PL-5E-II missile also has 1760 interface Air Commodore Khalid was asked if a helmet mounted sight (HMS) will become a part of any future block upgrade. “We will go directly to Helmet Mounted Display (HMD) technology. We don't have the definite time when we will end the process of integration but we are in the integration phase and we are doing it on the Block 1 aircraft”, he said.
http://ak-12.livejournal.com/60919.html