JF-17 BlockIII prototype machine (part one)-Speaking from the composite skin
Valkyrie
2020-01-03 23:29
The news of the first flight of JF-17 Block III (Fierce Dragon 3) did not produce "high-temperature fermentation" on the Internet media. The editor believes that there are two reasons for this: one is that the current Chinese military fans are in the blowout development mode of China's rapid military technology, their vision and style of appreciation have already risen, and fighters like the J-10C will all look at them. Not to the eye, let alone the lightweight and cheap model of JF-17; the second is that the current online article "Interpretation of JF-17 BlockIII Prototype", its interpretation perspective lacks new ideas, analysis of JF-17 BlockIII The content of the prototype itself is too little, and more of the content of the weapon system. It has a cliché and a sense of chewing wax. It can't lift the spirit at all, so it can't resonate... The editor dares to "look at the picture and talk" and speak out-even if not. If you are not a fan, even if the donkey's lips are not right, there is no regret. Whether it's applause or bricks, I am pleased with it...
The JF-17 BlockIII prototype has fewer photos, but the amount of information conveyed from the limited "photos" is enough to shock "wishful people" worldwide...
As early as 2015, the Pakistan Air Force has confirmed the existence of the JF-17 BlockIII improvement plan. In February 2017, Pakistan Aviation Complex (PAC) Chairman Assad Malik (Arshad Malik) emphasized through the media that the Pakistan Air Force (PAF) will issue a copy to the Pakistan Aviation Complex (PAC) in the first half of 2017. Purchase order for 50 JF-17 BlockIII fighters. JF-17 Block-III, as the latest improvement of the "Raiden" fighter, will be equipped with a quasi-fourth generation avionics system and active phased array radar.
JF-17 Block III prototype number 3000
The U.S. "Aviation Weekly and Space Technology" and "Defense News" are even more vowed to report that the technical performance of JF-17 Block III will be greatly improved, including the replacement of the 14th research institute developed by the "China Electronics Technology" Group. KLJ-7A active phased array radar, infrared search and tracking system added in front of the cockpit, helmet display/pointing system added for pilots, single large-size multifunctional color display (MFD) in the cockpit, new avionics, fire control software Wait.
So, through the "photos" of the JF-17 BlockIII prototype, can we confirm which of the above "old rumors"?
Big talk: "JF-17 BlockIII prototype" body skin!
Under normal circumstances, the body skin of the prototype is covered by "yellow", commonly known as "yellow skin machine". "Yellow skin" is actually an anticorrosive coating (anticorrosive paint) attached to a light alloy (usually aluminum alloy). In the part close to the tail nozzle of the engine, because of the high temperature, anti-rust treatment is required. Therefore, anti-rust paint needs to be added. Therefore, the skin on the tail of the body will be more vivid than the "yellow" skins on other parts of the body...
In addition to the "yellow" skin, there will be "gray" or "dark gray". Early radomes were made of high-strength glass steel materials, and the paint coating was off-white. With high silica glass fiber, aramid fiber, quartz fiber and other light weight, wave-transmitting, impact resistance, deformation resistance, and tensile resistance are better With the advent of composite materials, the color of the radome has gradually changed from "gray" to "dark gray." In addition, the "green" or "light green" body skin is also a sign of composite materials (such as carbon fiber materials, transparent fiber materials).
Comparison of JF-17 BlockIII (Fierce Dragon 3) Prototype and F-10C Prototype
The JF-17 BlockIII and J-10C in the picture are both in prototype state. By visually comparing the appearance, the following conclusions can be drawn:
First of all, JF-17 BlockIII and the J-10C prototype are in a completely different flight test phase.
The F-10C prototype in the picture has a dark gray fiber material (for example: polyethylene fiber, with excellent dielectric properties in the range of X band to mm band) installed at the nose cone of the nose. An airborne infrared detection and tracking system commonly known as "photosphere" has been installed in the front of the cockpit. This shows that the radar system and photoelectric system of the J-10C prototype in the picture have been installed in place, and its flight test mission has entered the stage of testing the fire control system and the passive perception ability.
On the other hand, the JF-17 BlockIII prototype has the nose cone painted in yellow, and it directly replaces the radome with lightweight alloy shaping. This shows that the JF-17 BlockIII prototype is not equipped with a radar system, only the same size counterweight model is arranged in the nose and nose cone according to the real radar system shape. This shows that the JF-17 BlockIII prototype shown in the photo is still in the initial stage of flight test tasks, and it is only at the verification stage to verify the aerodynamics, center of gravity trim, and whether the flight control and bus system control meet the design requirements. .
Secondly, the proportion of JF-17 BlockIII body skin using composite materials exceeds that of J-10C
Observe the JF-17 BlockIII and F-10C prototypes from the top-down perspective in the figure. The body of the JF-17 BlockIII prototype is covered by the composite body skin and is similar to the F-10C.
The composite skin of the JF-17 BlockIII prototype airframe starts from the "back" position of the airframe: it extends laterally to the position where the entire wing is flush with the distal end of the flaps, and integrates the JF-17's iconic "arched wing" It also covers them. Longitudinal, extending forward along the "back" of the fuselage, flush with the front of the "clam intake", and extending backward along the "back" of the fuselage to the level of the flaps. Due to the lack of a bottom view of the JF-17 BlockIII prototype, it is impossible to observe the under-wing skin material. However, according to the J-10C prototype for reference, it can be seen that composite materials are also used; in addition, the position of the first cockpit of the JF-17 BlockIII prototype is positive. On the lower sides, a large area of composite skin is also used.
The use of carbon fiber composite materials in Chinese fighters was first traced back to the "J-8II era", but it was limited by the level of carbon fiber production technology in China at that time, and the proportion was very small. China's first three-generation fighter J-10A with independent intellectual property rights, and its body skin carbon fiber composite material consumption reached 6%. The F-10B and F-10C use carbon fiber materials on a large area of the wings, and the amount of composite materials for the body skin exceeds 10%.
The layout of JF-17B prototype skin composite material is very similar to JF-17 BlockIII
In 2018, the JF-17B two-seater version that participated in the Pakistan National Day military parade has adopted a new vertical tail made of composite material skin. It is believed that subsequent JF-17 BlockIII prototypes will also use a vertical tail similar to JF-17B. At that time, the amount of skin composite materials used in the JF-17 BlockIII body will further increase. Then, the proportion of JF-17 BlockIII body skin composite materials will far exceed the J-10C, and even reach or exceed the order of 20%.
In the world, composite materials are also "expensive products". A generally accepted saying is: the use ratio of composite materials for the third generation machine is about 3% to 12%, and the use ratio of composite materials for the fourth generation machine is about 20% to 30%. % (Of course, Asan’s "Glorious" fighter is a special case, the proportion of composite materials used is as high as 40%, in addition to being admired, it can only be admired).
So, the JF-17 (Xiaolong), which is positioned as a light and cheap third-generation machine, and its latest improved model, adopts such a "large-scale" use of composite materials, which can only be described as "awesome"...
Big story: Who gave JF-17 BlockIII the confidence to use composite materials?
The manufacturing level of composite materials is a measure of a country's aerospace and aviation industry manufacturing capabilities, and it is also a mirror that comprehensively reflects a country's basic research, precision manufacturing, and industrial hard power. Therefore, the technological competition and competition in the field of new materials by the major technological powers is extremely cruel.
The European and American powers have generally adopted composite materials from the era of the "third-generation machine". Under the premise of ensuring that the structural strength of the fighter aircraft meets the design requirements, the composite material can greatly reduce the fighter’s own weight, and its anti-fatigue, anti-deformation, and anti-rust properties are superior to aviation alloy aluminum. Some special composite materials also have The function of reducing the strong reflection of radar waves. The production and manufacturing process of fighter aircraft and the proportion of composite materials used can, to a certain extent, truly reflect a country's technical level in many aspects such as materials, craftsmanship, and design.
The Western world has imposed embargo and blockade policies on China for a long time in the production and manufacturing of composite materials.
Take carbon fiber composite materials as an example: Carbon fiber materials can be roughly divided into high-strength T series, high-modulus M series, and high-strength and high-modulus MJ series according to technical indicators such as "tensile strength, elastic modulus, and elongation at break". In the high-strength T series, it is divided into general standard model (T300 level), high-strength standard model (T700 level), high-strength medium model (T800 level), high-strength model (T1000 level) and ultra-high-strength medium model (T1100).
T700 and T800 grade carbon fiber composite materials are commonly used in military aircraft, missile (intercontinental missile) manufacturing and spacecraft manufacturing. Therefore, Europe and the United States have formulated extremely strict embargo policies on such carbon fiber materials, technology and production. , There have even been incidents in which Chinese businessmen purchased T800-related products in the United States and directly became defendants.
Research on composite materials in China began in the 1960s (or even earlier), but it has long been limited by basic research, weak industrial foundations and financial support, and a shortage of relevant talents. As of the beginning of the 21st century, China has only Complete small-scale industrial production and manufacturing of T300 series products.
With the continuous continuation and deepening of reform and opening up, the country’s comprehensive national strength has continued to increase. The materials will be reviewed from the outline of the national key R&D plan in the “Eleventh Five-Year”, “Twelfth Five-year With the continuous increase of financial support and investment in the scientific field, China's composite material technology has begun to blow out.
Since 2009, China has successively broken through the large-scale industrial production technologies and processes of T300, T700, T-800, M30, M55, and T1000 carbon fibers in the carbon fiber field. In 2018, China broke the T1100 carbon fiber production and manufacturing technology that has been monopolized by Japan in one fell swoop. This is the world's strongest and most cutting-edge carbon fiber technology. In 2019, China has achieved small-scale production of 100-ton T1100 carbon fiber, and the 1,000-ton production line is expected to be realized after 2020.
At present, China's carbon fiber production output ranks second in the world, and China's T700, T800 and T1000 carbon fiber production capacity has reached 10,000 tons and 1,000 tons respectively. In China's arsenal, the Dongfeng series of new missiles, the Eagle Strike series of new and modified missiles, the Hongqi series of air defense missiles, the F-20, FC-31, and the F-16 all use domestic carbon fiber materials.
Chinese carbon fiber materials have "Chinese characteristics". Take T800 carbon fiber as an example: domestic T800 carbon fiber has an average tensile strength of 5.63 GPa, an average elastic modulus of 292 GPa, and an average elongation at break of 1.9%. The modulus of elasticity and elongation at break are equivalent to the Japanese T800 grade, but the average tensile strength is stronger than the Japanese T800 grade. However, under the large-scale industrial production mode of China's T800 grade carbon fiber, its cost is only ⅓ of similar international products, less than 350 yuan per kilogram.
So, where does JF-17 BlockIII's massive use of composite materials come from? We are still more reserved, the benevolent see benevolence, the wise see wisdom, it is better!
Final summary
In recent years, there have been many instances of T800-grade carbon fiber materials being applied to the body skins of new-generation third-generation and fourth-generation aircraft. The famous French Rafale M, in its promotional materials, praised its body composite material, which is too high a lot of "worth" (due to the earlier development of F22, its carbon fiber material is T700 grade).
JF-17B two-seater version lined up offline
On April 27, 2017, the JF-17B two-seater version of Xiaolong flew for the first time. This is the "first model" of JF-17 series fighters using composite materials in large quantities, and the first foreign trade model to enjoy the "technical dividend of China's T800 carbon fiber material". On December 28, 2019, the JF-17 BlockIII prototype flew for the first time. This must be a foreign trade model that enjoys a higher and wider “Chinese technology dividend”.
The Pakistani military has a "quasi-four generation" desire for JF-17 BlockIII's comprehensive combat performance. Whether this goal can be achieved is still very uncertain. However, if we ignore the uncertain factors such as weapon systems and electronic equipment, and only look at the application technology and level of the body materials, it seems to be really interesting...