Set the general principle of purchasing domestic goods, and the next choice is actually very simple.

"If you want to buy domestic fighters, the third-generation fighters you can choose at present are J-10 "Raptor" and J-11 "Diplodocus"; The question is, how exactly do you choose between the two? ”

Asking questions for Liu Wei to think about it, holding up the crystal clear glass, staring at the ups and downs of the tea leaves in the cup, Long Yun did not speak more, but fell into a long thought like Liu Wei.

Choose J-10 or J-11, how to answer the question of choosing one of the two?

As a member of the Alliance of Eastern States, China is currently able to mass-produce and sell third-generation fighters at any time, mainly the J-10 series, which is designed and manufactured by itself, and the Su-27SK from the Soviet Union/Russia, and the J-11 series, which was later localized.

Of course, a consensus had been reached in the previous conversation with Shangguan Ling that for the fledgling "Chenlong" team, the typical fourth-generation stealth fighter is too advanced and too expensive, and they can't consider it for the time being; In addition, there are a variety of other niche models, such as the J-7 series of Xi'an Aviation Industry Company, and the old J-8II series fighters of Shenyang Aviation Industry Company.

"Raptor" or "Diplodocus", who is more suitable for the two?

Not only Long Yun and the others, who are now thinking about it, but it is estimated that many aviation competitive teams have been entangled in this issue when choosing a model: the two models that seem to have many similarities are actually the products of different combat styles and under the guidance of different strategic ideas, and they also have different impacts on the combat styles of users.

The prototype of the J-11, the Su-27, is a high-performance heavy fighter developed by the Soviet Union at the same time as the MiG-29 in the seventies of the last century. Although it was put into production quite late compared to its old rival F-15, its revolutionary design, which was different from the previous Soviet fighters, made it the most powerful third-generation fighter in the Soviet era.

For this kind of air combat weapon, Long Yun has mastered it skillfully in the parallel world he has traversed and understands it very thoroughly; However, in order to understand its combat characteristics, it is necessary to start with the operational requirements formulated at the time of development.

In the 1970s, when faced with the real threat of advanced fighters of the NATO Air Force, the Soviet Union demanded that all aircraft design bureaus come up with a new generation of fighter plane design plans, no longer deliberately pursuing simple design and mass production, but requiring them to be able to accomplish complex combat missions and have the strength to confront NATO's latest fighter planes head-on. The new fighter needs to have two typical mission capabilities: one is to fight with the enemy fighter and seize air supremacy, which requires the fighter to have excellent combat maneuverability; Second, it is necessary to intercept enemy bombers, cruise missiles, and other high-threat targets, which requires fighters to have a strong target search capability and abundant fuel and ammunition support.

Under the guidance of this design idea, the Soviet MiG Design Bureau and the Sukhoi Design Bureau each completed the design tasks given by their superiors, and provided the MiG-29 and Su-27, two new-generation fighters with similar aerodynamic layouts and similar weapon systems, but very different combat modes.

Unlike the MiG-29, a front-line fighter with relatively simple equipment and a focus on combat, in terms of the specific division of labor of different models, it should be said that the Su-27 is mainly designed to perform the second type of mission, that is, long-range interception and air interdiction; However, due to the unremitting efforts of the designers, the final product T-10S can be said to be better qualified for these two tasks, and it is a truly all-round and powerful model. It is precisely because of this that the Su-27 became the first model of the former Soviet Union to be massively equipped with VVS (Soviet Air Force) and PVO (Territorial Defense Forces of the USSR) at the same time, which was previously unthinkable.

However, just as nothing is perfect, the Su-27 has to make some compromises and compromises in its design while it has the advantages of superb maneuverability as a combat fighter and the range and bomb load of a heavy fighter.

Those who are familiar with the appearance of the Su-27 know that the Su-27 has a long shape rich in mechanical beauty and smooth lines: from the bowed front fuselage to the tail vertebrae protruding from the tail vent, it is nearly 22 meters long, which can be said to be the second longest third-generation fighter aircraft, second only to the huge MiG-31. It can be said that the Su-27 does have a good figure, but if you pay attention to the fact that its empty weight and maximum take-off weight are not much different from other heavy fighters of the same era, such as the F-14 and F-15, you can understand that the Su-27 is actually a rather slender fighter.

In general, a longer fuselage configuration (that is, a larger slenderness ratio) can achieve a higher maximum flight speed without increasing the thrust of the fighter, which is also in line with the design positioning of the Su-27; The Chinese J-8 series fighter is a typical example of this design, as a medium-sized fighter, its overall length is even a little longer than the huge Su-27, and it looks like a sharp long arrow.

However, the Sukhoi Design Bureau, when designing the Su-27, sought to allow it to meet the multifaceted operational needs and not just exist as a long-range heavy interceptor; In this regard, the "optimal aerodynamic layout of the twin-engine fighter" provided by the Central Air and Fluid Configuration Research Institute gave them sufficient support, and its biggest feature was the adoption of the most advanced wing-body fusion concept in the world at that time.

The Su-27 fighter with this layout can still achieve good lift and attitude control performance without greatly increasing aerodynamic drag, which can be said to be a quite successful design.

However, it is not enough to have a wing-body fusion: the designers also need to choose the right airfoil for the Su-27.

When it comes to the consideration of wing airfoil, if it is purely to improve the interception performance and make the fighter aircraft have good acceleration characteristics and maximum flight speed, the delta wing should be a better choice, just like the large number of Su-15 and Su-11 equipped by the Territorial Defense Force. But if you want to pursue excellent maneuverability, then the delta wing is not a very good choice.

Taking into account the maneuverability, the Su-27 did not use a delta surface like its codename "T-10", but opted for a trapezoidal wing with a medium swept angle, a design that approximates the swept wing but has better performance.

The choice of trapezoidal wing improved the maneuverability of the fighter while reducing the aircraft's high-speed performance, which the Sukhoi design team compensated for with the AL-31 turbofan engine of the Rurika Design Bureau - the 25 tons of afterburner thrust provided by the two powerful AL-31s could ensure the high-speed maneuverability of the Su-27, which was quite close to the F-15, which was also a heavy fighter but used a double delta wing.