The MiG-21 is the most famous aircraft in the world. It is the legendary and most widely used supersonic combat aircraft in the world. It was mass-produced in the USSR from 1959 to 1985, as well as in Czechoslovakia, India and China. Due to the mass production, it was distinguished by a very low cost price: the MiG-21MF, for example, was cheaper than the BMP-1. In total, the USSR, Czechoslovakia and India produced a record number of fighters - 11496 units. The Czechoslovak copy of the MiG-21 was produced under the name S-106. The Chinese copy of the MiG-21 was produced under the name J-7 (for the PLA), and its export version, the F7, continues to be produced at the present time. As of 2012, about 2,500 J-7 / F-7s were produced in China. He has proven himself in almost all conflicts in which he participated. And he participated in all more or less major conflicts that took place in the period after its creation - up to the present day.
The MiG-21 is truly the pride of the Russian aircraft industry. But history could have turned out differently, and another plane could take the place of the MiG-21. Would it be worthy of the glory of the MiG-21, or, on the contrary, would any alternative choice be a losing one?
The start of the development of new generation fighters was given by the Decree of the Council of Ministers of the USSR of July 5, 1953, which ordered the "fighter" design bureau to start developing new types of aircraft; designed for high supersonic flight speed (at least 1750 km / h). It was the work under this decree that led to the birth of the MiG-21 and its competitors in the competition.
We'll start with the most unknown competitor. The Yak-140 fighter, created in the mid-1950s at the Yakovlev Design Bureau, is still little known both for the West and for domestic aviation historians. In accordance with the government decree of September 9, 1953, the OKB A. S. Yakovlev was instructed to develop and build two copies of the Yak-140 and the first of them to be presented for state tests in March 1955. The decree specified the following characteristics: maximum speed 1650 … 1750 km / h, service ceiling 18,000 m, flight range 1,800 km at altitude 15,000 m, take-off run 400 m, run 600 m. A. S. Yakovlev viewed the Yak-140 as a further development of the idea of a light fighter, whose ideas were embodied in its immediate predecessor, the Yak-50.
It should be said that performed with the traditional leadership of the team of A. S. Yakovlev in the culture of weight and the thoroughness of aerodynamics development, the Yak-50 with the same engine outperformed its contemporary MiG-17 in all flight characteristics. Looking ahead, let us say that the same techniques allowed A. S. Yakovlev to create a Yak-140 1400 kg (!) Lighter than the MiG-21.
The draft design was approved by A. S. Yakovlev already on July 10, 1953. The main idea of the creators of the Yak-140 was clearly defined in the draft design: “This draft design of a front-line fighter with an AM-11 engine is a further development of the idea of a light fighter, which has been pursued for a number of years. The proposed fighter successfully combines the parameters of a small-sized light aircraft and provides outstanding flight and combat qualities guaranteed by an unsurpassed thrust-to-weight ratio … Flight data: vertical speed at the ground 200 m / s, and at an altitude of 15,000 m - 30 m / s; service ceiling exceeds 18,000 m; the maximum speed at altitudes of 10,000-15,000 m reaches 1,700 km / h. Possessing low wing loading and high thrust-to-weight ratio, the light fighter has excellent maneuverability both in vertical and horizontal planes."
The Yak-140 was supposed to have a turbojet engine A. A. Mikulin AM-11 with a thrust of 4000 kgf and 5000 kgf in forced mode (the same engine was chosen for the MiG-21, which makes the comparison of these machines even more interesting). Compared with the options calculated by the Design Bureau for the engines TRD-I (future AL-7) and VK-3, the aircraft with AM-11 with the best flight characteristics and the same equipment and weapons was twice as light (4 … 5 tons versus 8 … 10 tons for a heavy fighter), two to three times more economical in terms of the consumption of non-ferrous metals, three to four times in terms of the complexity of construction, and two times in terms of fuel consumption.
The time when the Yak-140 was designed was distinguished by a very dynamic development of combat aviation, while flight speed became extremely important. The rapid progress in the field of aerodynamics and aircraft engine building opened up such prospects that until recently seemed fantastic. In just 5-6 years, the speed of fighters almost doubled, and in many ways this pursuit of speed went to the detriment of maneuverable characteristics. Aviation specialists' ideas about air combat have undergone serious changes, which was largely facilitated by the emergence of air-to-air guided missile weapons. The most striking example is the Lockheed F-104 Starfighter, which was one of the fastest and least maneuverable fighters. It was the information about the development of the F-104 that excited the Air Force command and served as the basis for the formation of the assignment for the new fighters.
The designers of the Yak-140 took a different path. They deliberately sacrificed speed for good maneuverability. For this, the Yak-140 wing was made somewhat larger than was customary for high-speed aircraft of this class. At the same time, the maximum speed was reduced by 150-200 km / h, but maneuverability and take-off and landing characteristics were significantly improved. Low values of the specific load on the wing (at takeoff 250 kg / m², and at landing 180 kg / m²) and low pressure of the wheels on the ground (6.0 kg / cm²) allowed the aircraft to be operated from unpaved airfields. In addition, the vertical speed of descent was significantly reduced and thereby facilitated the landing of a fighter with a stopped engine, which was considered by the designers as an important element of increasing safety and survivability. The Yak-140 was supposed to have a phenomenal thrust-to-weight ratio for its time, which, according to calculations, was slightly more than 1 (!), Which corresponds to the performance of modern F-15, F-16, MiG-29 or Su-27 fighters. For comparison: this indicator for the MiG-21F (1958) was 0.84, and for the F-104A - 0.83. battle. Thus, A. S. Yakovlev showed design perspicacity, and in the distant 50s created his fighter according to the same principles on the basis of which the fourth generation air superiority fighters were created in the 70s and 80s.
When designing the aircraft, great attention was paid to simplicity and ease of operation - a convenient layout of equipment and weapons, wide hatches in the fuselage, the possibility of undocking the tail section of the fuselage to replace the engine, easily removable tail spinner of the fuselage for a free approach to the tail section of the engine. The rudder and engine control wiring runs along the top of the fuselage and is closed by a hinged fairing (gargrot). The electrical wiring is laid in easily accessible places, and a significant part of it is under the gargrotto. It should be noted that such an approach was not yet generally accepted, and the Su-7, F-102 (106) and others developed in the same years, caused well-deserved criticism from the service personnel.
The constructive solution of the main frame units is linked to the requirements of the serial production technology. Operational and technological connectors of the units by panels provide a wide scope of work, riveting using advanced methods and carrying out assembly and assembly work separately for panels and units, and, consequently, in-line assembly. The wide application of stamping and casting is provided. The small size and operational connectors of the fighter made it possible to transport it by rail on one platform.
One of the main features of the Yak-140 is its high survivability. The calculated vertical speed of descent when gliding with the engine off does not exceed 12 m / s with the landing gear extended and flaps deflected. Therefore, landing with a failed engine is possible. The hydraulic systems for landing landing gear and flaps, as well as braking the wheels of the main landing gear are duplicated by the pneumatic system. The front and main supports are released downstream, which provides emergency landing gear even at low pressure in the pneumatic system. The control of the elevator and ailerons is irreversible, carried out by means of rotating shafts, operating in torsion and experiencing a small load. Therefore, shooting through one or more shafts is much less dangerous than shooting through reversible control rods operating under significant tension or compression loads. The engine is equipped with an alarm and fire extinguishing system. The low pressure fuel filter is protected against icing in flight. An emergency shutdown system for afterburning is installed.
The sweep of the wing along the chord quarter line was 55.5 °. The relative thickness of the root profile is 6, 3%, the end profile is 8%. The transverse V of the wing was -4.5 °. The wing was equipped with retractable flaps and ailerons with weight compensation. Two aerodynamic ridges were installed on the upper surface of each console.
In the forward part of the fuselage there was an unregulated cone, in which the radio rangefinder units were located. Fuel (1275 kg) was placed in tanks located behind the cockpit and in the aft fuselage. The cockpit is sealed, with an ejection seat. In the event of an emergency reset of the canopy, the air brakes located on the sides of the rear fuselage were automatically opened, which increased the safety of the ejection. Armament: three 30 mm cannons with 50 rounds of ammunition. In the reloading version: 16 ARS-57 missiles of 57 mm caliber or eight ARS-70, or two TRS-190, or up to 200 kg of bombs. Automatic optical sight with a radio range finder. Of the two types of experimental aircraft guns of 30 mm-235P and TKB-500 caliber, the 235P OKB-16 AE cannon was chosen. Nudelman. She had advantages in size, weight, design simplicity, reliability, rollback and other parameters (the future HP-30, which was put into service in 1955).
The chassis on the Yak-140 was of a bicycle type, which was already becoming standard for Yakovlev's post-war aircraft. It consisted of the main, front and two underwing supports. Air-oil depreciation, the design of all struts is lever. The main support was equipped with two brake wheels 600 × 200 mm, and the front one was equipped with a hydraulically controlled wheel 480 × 200 mm. Underwing supports with wheels 250 × 110 mm were retracted into the fairings located at the ends of the wing. LDPE was installed on the same fairings. Cleaning and release of the chassis was carried out using a hydraulic system (emergency release - pneumohydraulic). The front and main landing gear were released downstream, which guaranteed their release even with low system pressure.
In 1953, the Soviet Union began to implement a program to create a new generation of fighters, distinguished by high supersonic speed. In the design bureau A. S. Yakovlev and A. I. Mikoyan, when creating such aircraft, relied on the A. A. Mikulin AM-11, and at the "firm" P. O. Sukhoi - much more powerful and. naturally heavy engine A. M. Cradle AL-7. Actually, AM-11 and AL-7 in 1953-54.did not exist yet, they were developed in parallel with the aircraft. However, the pace of work on Yak and MiG fighters turned out to be higher than on the AM-11 engine. Then in both design bureaus they decided to build experimental models of cars for a serial engine of lower power AM-9B * (thrust on afterburner 3300 kg) or its modification AM-9D. This is how the Yak-140 with the AM-9D appeared, as well as the Mikoyan E-2 and E-4 with the AM-9B. Yak-140 with AM-9D was completely similar to the main version with AM-11. The differences were only in the elements associated with the power plant, and in the armament, which consisted of two 23-mm NR-23 cannons. The radio rangefinder was not installed. It is clear that it was not planned to receive the declared flight data on this fighter. It was intended for testing and fine-tuning systems and units, identifying control features, which would speed up the commissioning of the main version of the machine.
This experimental fighter was built at the end of 1954. In January 1955, ground tests began; taxiing, jogging to lift-off speed, etc. Meanwhile, TsAGI conducted statistical tests of the main version of the Yak-140. It turned out that the wing of the aircraft needed to be strengthened, but this did not in the least interfere with the first stage of flight tests. Nevertheless, in February 1955, work on the aircraft was stopped literally on the eve of the first flight and was no longer resumed. A satisfactory explanation for this fact has not yet been found, we can only state that there was no official decision of the Ministry of Aviation Industry to curtail work on the Yak-140. The need to rework the wing cannot be regarded as a serious reason for abandoning the aircraft, since such cases have often occurred before. The technical problems that arose in this case were solved, as a rule, quickly and quite successfully. Interesting information shedding light on this story was told in the magazine "Aviation and Time". According to one of the KB veterans, when asked about the fate of the Yak-140, asked by A. S. Yakovlev many years after the events described, he replied that the then Minister of the aircraft industry of the USSR P. V. Dementyev, without any explanation, informed him of the futility and senselessness of the design bureau's attempts to continue work on the Yak-140, since preference would still be given to another aircraft. Now one can only guess what motives the minister was guided by. Yakovlev, well aware that without the support of the MAP leadership, the design bureau would not be able to achieve success, ordered to stop all work on this aircraft.
But did the Yak-140 have a chance to be put into service and take the place of the MiG-21? I think that even without the above fact, Yak had no chance. At that time, the example that stood before the eyes of the leaders of the Air Force and the Ministry of Defense was the F-104 - the first combat aircraft to overcome the speed of 2.0M. High-altitude and high-speed battles on converging courses were seen as the basis of the tactics of the upcoming battles. Consequently, the main characteristics influencing the choice of the aircraft were precisely the speed and altitude. And the Yak-140, which was ahead of the whole world in its concept, was losing to competitors in these indicators, and would become an outsider in the competition. The understanding of the fallacy of non-maneuverable combat will come later, after the Vietnam War and the Arab-Israeli conflicts. It was there that the Yak-140 could realize its potential. Real battles showed that the MiG-21 in close air combat was approximately equal to the Mirage-3, and victory depended solely on the pilot's experience and the right tactics. If the Yak-140 were in its place, and the rule of the MiG-21 pilots "I saw the Mirage" do not take a turn "would no longer make sense. Considering the outstanding climb rate and lower wing loading, the Yak-140 should have significantly outperformed the Mirage-3. In a battle with the F-4, the Yak-140 would generally be equal to the MiG-21. The Yak-140 also surpassed competitors in flight range (the main drawback of the MiG-21 and Su-7), and the weight reserve made it possible to further increase the gap. But the history of the Yak-140 ended before it began. And the only thing in which he became a milestone is in the work of the OKB A. S. Yakovlev, becoming the last one-seat front-line fighter built in this design bureau.
