It’s rare which aircraft underwent larger-scale structural changes during the design process than the Su-24. The characteristics of this front-line bomber were constantly required by the customer (the Ministry of Defense of the USSR), and aircraft designers had to revise several times not only private technical solutions, but also the general conceptual scheme. The result exceeded expectations: the device turned out well and, having outlived its age, was in demand even in the third millennium.
On pure enthusiasm
In the fifties, the whole world was in the grip of "rocket hysteria." It seemed to military theorists that airplanes as a striking force, if not completely out of date, then at least lost their decisive importance in modern combat. These conclusions were fully applied to attack aircraft. However, this extremely bold point of view was not shared by all, and the development of attack aircraft still continued. As part of the budgetary savings, the Design Bureau of P.O. Sukhoi was engaged in the adaptation of a very successful Su-7 aircraft to give it the ability to solve the combat task of supporting ground troops in difficult weather conditions. Actually, under the guise of modification work, the collective actually created a completely new car, and the version of improving the old one was invented for party officials who were imposing their general line on the “techies”. Various layout options were considered, taking into account the possibility of placing complex electronics, without which a modern attack aircraft could not become a formidable force.
Creative search
The result of creative torment was the first Su-15, equipped with an all-weather navigation system "Orion". But the requirements of the military were becoming tougher, they now needed to attack aircraft could take off from the unpaved strip, and short. The search for the optimal solution continued, additional engines were added to the design, raising the aircraft at the time of takeoff. But all this was not right. O.S. Samoilovich, project manager, puzzled over the resolution of this rebus. And the clue came, oddly enough, from a likely opponent.
It was in 1964, Khrushchev was recently removed, and the new leadership of the country did not think so romantic, but pragmatic. The design of combat aircraft again received full funding. Designer Samoilovich flew to Paris for an aerospace exhibition. He saw something interesting there.
American in Paris
They look very similar in appearance - the American F-111 and our Su-24. Photos, specifications and combat capabilities, and most importantly, the purpose of these two aircraft are very close. In a sense, Samoilovich made a direct borrowing of the general layout scheme, however, quite justified. The General Dynamics company proudly exhibited its brainchild at the international salon in Le Bourget. Everyone could see the plane, but the chief designer did not immediately decide to come close to him. Then he took his FED and at that moment he realized what the Su-24 would be like. Photos of the F-111 aircraft in Moscow were examined very carefully, engineers admired the skill of the rivals and commented on what they saw.
Of course, the fact that the design was "stolen" from the Americans is out of the question. General Dynamics can keep secrets, and if the Soviet side got access to them, it happened much later. In the meantime, O.S. Samoilovich had enough of the appearance. As the ancient Romans wrote in their drawings in such cases, “smart enough.”
General scheme
Additional hoisting engines that reduce takeoff during take-off were considered a wrong decision. They work only in the first seconds, and their plane should carry them all the time. Another thing is the wing of variable sweep, its advantages can be used throughout the combat mission, transferring the attack aircraft to different speed modes.
At the same time, there were some difficulties with the weapons that should have been carried on the external suspensions of the Su-24. The bomber automatically directs the pylons of missiles and bombs parallel to the heading vector - this required a special matching electromechanical system. A spacious compartment for two radar antennas made it possible to place a powerful BREA, which was not the case with previous models of Sukhoi Design Bureau front-line support aircraft. But the main difficulties were ahead.
Flat flight
The purpose of a tactical bomber is to damage the enemy in a wide (up to 800 km) front line. To realize this task, it is necessary to have the technical ability to overcome the frontiers of air defense, which, accordingly, will predictably carry out maximum resistance. In the sixties, radars were not as perfect as they are today, and targets at low altitudes were not always “seen”. The same applies to airborne radars, which could not distinguish between objects on the background of the earth. The American F-111 flew at extremely low altitude, enveloping the terrain. The same task was set for the designers of the Su-24. At the same time, high-speed characteristics did not decrease; a confident “supersonic” was required even during a lay flight.
The system for maintaining safe envelope of obstacles works in two modes - manual and automatic. Given the elemental base of the 60s (mainly lamps), one can only admire this achievement.
Fuel consumption and combat radius
In those distant years, the issue of fuel economy was not an acute issue. However, kerosene consumption affected a very important indicator - range. To improve it, a revolutionary solution was required - the transition to economical dual-circuit engines. In afterburner mode, they developed less traction than conventional turbofan engines, but, as experience has shown, the tactical bomber practically does not need the possibility of a sharp increase in speed. The design of special engines was taken over by the design bureau of Lyulka and Tumansky (Saturn). They were intended exclusively for the Su-24. The combat radius of the aircraft has increased significantly - it exceeded five hundred kilometers.
Let's sit down next to ...
Almost all tactical bombers and attack aircraft of the Second World War and subsequent years had a tandem crew layout. The planting of the pilot, navigator or operator of the weapon systems one after another of the designers was prompted by the desire to reduce the cross section of the fuselage. So the aerodynamic drag was reduced. In addition, the size of the target, from the point of view of anti-aircraft artillery, also had a value in a frontal attack. The real revelation was the placement of two crew members next to each other in the American F-111. O.S. Samoilovich decided to apply this scheme to the Su-24. The photo of the cockpit demonstrates the presence of the control stick and the navigator, however, it is somewhat smaller than the pilot. Security considerations dictated a special screen that separated the seats during ejection, but later it turned out that the risk of injury to the pilot who remained on the plane was minimal. The exchange of information between the pilot and the navigator was greatly facilitated, a "feeling of the elbow" appeared.
Engine and titanium fires
The technical characteristics of the Su-24 were significantly influenced by the choice of engine. The first copies were equipped with "product No. 85", that is, the AL-21F jet turbine, in the compressor of which titanium parts were used. This material is very strong and light, but when designing the engine, the designers did not take into account some of its features. The heating of the turbine blades led to their lengthening, and then to the contact of the casing with their peripheral edges. This phenomenon, called the "titanium fire", led to almost instantaneous combustion of the entire aircraft, but it was not possible to find out the cause right away.
Ultimately, after several attempts to adapt other serial engines, KB decided to refine the AL-21F, which is currently used.
Hard trials
During the first flight, the prototype, which received the T6-1 index, was raised in 1967 by test pilot BC Ilyushin, the son of a famous aircraft designer. The test was successful, but in the course of improvements serious structural defects were identified. The tests were long and hard, during their period ten cars crashed (7 of them - due to errors of engine developers). In just one day in 1973 (August 28), the Design Bureau lost two prototypes. Perhaps if the project was less important for the country's defense, it would be closed after so many failures. But O.S. Samoilovich believed in the Su-24, whose characteristics promised to be excellent. And the tests continued, as did the work to eliminate the identified structural failures.
Air strike power
Bomb compartments, unlike the American F-111, the aircraft is not equipped, all types of weapons are located on eight pylons, four of which are dorsal. Two powerful engines provide the ability to carry both conventional and special (nuclear or chemical) ammunition, including high power. Thus, pendants on the fixed part of the wing are designed for bombs weighing half a ton. The nature of the weapons of the Su-24 is diverse. The combat load with a total weight of up to eight tons may consist of unguided or adjustable bombs (including those with laser guidance), NAR units, containers or cartridges. To maintain such a wide range, the pylons are equipped with transitional devices and additional beams. But not only bombs can strike Su-24: this bomber can be called a missile carrier.
Rockets
The task of suppressing the air defense of a probable enemy is inextricably linked with the detection and destruction of radar posts, in the first place - antennas of emitters-receivers. In America, the Speike anti-radar missile was developed for this purpose (1963), whose guidance system focuses on intense high-frequency radar emissions. A similar X-28 projectile was also designed in the USSR to complete the Su-24 aircraft weapons system. The combat capabilities of this ammunition are revealed most widely during the pair departure of two bombers, the first of which “tracked” the locators with the Filin system, and the second delivered a direct strike, already knowing the parameters of the carrier frequencies of the emitters. X-23 guided missiles are guided by the radio command method.
There are many more options for arming with Su-24 rockets. Photos of an aircraft equipped with NURS cassettes or R-60 missiles ("air-to-air") prove the universality of the possible use of a bomber, including against air targets. Of course, it cannot be called a full-fledged interceptor, but it is also impossible to consider it defenseless in the sky.
Designers did not forget about artillery weapons. Su-24 is equipped with a 23-mm six-barrel gun GSH-6-23M (built-in). It is possible to quickly increase firepower by installing suspended quick-firing gun mounts (three more) on the external nodes of the suspensions.
Product "44"
Any successful car is doomed to a long life, accompanied by attempts to improve its design. This happened with the Su-24. His characteristics, from the point of view of the leaders of the Ministry of Defense of the USSR, needed correction. Particularly urgent was the task of improving the on-board electronic equipment and the possibility of increasing the mass of the combat load. The new modification, which the Novosibirsk Aviation Plant has called the “Product 44” since 1979, began to enter the military units under the code Su-24M in 1981. Officially, the sample was adopted in 1983. It turned out to be heavier than the prototype, but against the background of a slight decrease in flight data, it retained the stunning maneuverability characteristic of a “pure” Su-24. The characteristics allow even aerobatics to be performed, which is a rare property for a front-line bomber.
An important innovation was the ability to refuel in flight. The pilots of the early eighties had to get used to it, having worked out the technique of a smooth approach to the cone of the refueling hose, but the result justified the efforts. The radius of combat use now covers the whole of Europe (during takeoff from the aerospace aerospace zones) and a significant part of Asia.
Su-24 and the new century
And at the beginning of the third millennium, nothing indicates that the Su-24 plane will soon leave for a “well-deserved rest”. Its characteristics are such that it can confidently carry out combat missions for many more years. He happened to fight in several conflicts that arose after the collapse of the USSR. The aircraft has a robust glider, powerful engines and a wide arsenal. At an altitude of 200 meters, it can fly at a speed of up to 1400 km / h. Su-24 is equipped with unique crew rescue equipment. He will still have to serve his native country.