In 1942, when no one could yet confidently say who would win the raging war, Myasishchev and Tupolev were asked to develop four-engine bombers with M-71TK-M engines, pressurized cabins and cannon armament. The maximum speed was 500 km / h at an altitude of 10,000 m, a range of 5,000 km with two bombs of 5,000 kg and 6,000 km with a bomb load of seven to eight tons. The draft design was ordered to be prepared by September 15, 1943.
In 1944, the requirements for a long-range bomber changed. By the resolution of the State Defense Committee A. N. Tupolev was ordered to design an aircraft with AM-43 engines and TK-300B turbochargers, which soon received the serial number "64". S. V. Ilyushin was instructed to develop an Il-14 with AM-43 engines with a direct fuel injection device, and V. M. Myasishchev and I. F. Nezval were guided by the ASh-72TK radial air-cooled engines. Interestingly, only to the decree on the bomber A. N. Tupolev prepared an application entitled "Measures to ensure the construction of four-engine aircraft …"
The Air Force TTT assigned the following performance characteristics to a long-range bomber:
• the maximum speed at a design altitude of 10,000 m should be 630 km / h;
• time of ascent to a height of 10,000 m - 40 min;
• practical ceiling - 12,000 m;
• flight range at V = 0.8 max. at a design altitude of 10,000 m with a bomb load of 4 tons - 6,000 km;
• takeoff run with fully filled gas tanks and 10 tons of bombs inside the fuselage - 600 m;
• take-off distance up to 25 m climb - no more than 1200 m;
• landing speed without bombs with 25% fuel reserve - 140 km / h;
• run length - 400 m;
• aircraft crew - 11 people (two pilots, two navigators, four gunners and one flight technician, radar operator and radio operator).
According to the resolution, V. M. Myasishchev (OKB-482) developed and submitted to the People's Commissariat at the end of December 1945 a draft design of the DVB-202 bomber. When preparing the project, the OKB did a lot of work on the general layout of the entire machine in several versions. Together with TsAGI, the wing layout was selected by selecting the most advantageous aspect ratio and profiles. The options for the placement of remote small arms providing spherical shelling have been worked out in detail, the propeller-driven group of ASh-72TK engines has been developed. The calculation was carried out for strength, aerodynamics, as well as for high-altitude, hydraulic and electrical equipment of the aircraft. In parallel with the above works, the OKB issued working drawings of the front cockpit, and even its full-scale mock-up was built.
In the process of working out the preliminary design, the possibilities of using not only the ASh-72TK, but also other engines: VK-109 and AM-46TK were considered. So, when installing the VK-109 engines, the flight weight of the aircraft, in comparison with the version equipped with the ASh-72TK, slightly decreased, decreased by 10-15 km / h and the maximum speed, but the maximum range from 5000 kg of bombs increased by 1000 km.
When working on the DVB-202 project, the American experience in building heavy bombers of the B-29 type and, of course, the experience gained during the creation and flight tests of the DVB-102 was taken into account. Therefore, the flight performance of this aircraft was significantly higher than that of the American B-29 bomber.
Only the calculated range of the DVB-202 was slightly lower than that of the B-29. This was due to the fact that the Americans, due to their remoteness from the bases of potential adversaries, were forced to build aircraft with a long range. For us, the range factor was of lesser importance, and by reducing the range, it was possible to increase other characteristics of the aircraft: climb rate, ceiling and speed. With the available range, the DVB-202 with its range captured Great Britain, France, part of Spain, Italy, as well as part of North Africa, including Tunisia, the Suez Canal, upper Egypt, the northern part of the Persian Gulf, while carrying 5000 kg of bombs. Thus, the requirements for a continental bomber were met in full, and at that time they did not aim at the intercontinental range.
According to the project, the aircraft had three pressurized cabins. The front cockpit housed pilots, navigators, a radio operator, a flight technician and an upper installation gunner. The navigators' workplaces were located in front of the pilots. In the middle pressurized cockpit - arrows of the lower and upper installations. In the rear (tail) pressurized cockpit there was a tail gunner. The radio operator was located in one of the cabins with the provision of conditions for working with radars.
The most serious attention was paid to the aircraft armament and its rational placement. It was planned to install five cannon points on the plane with 10 cannons of 20-23 mm caliber:
• for shelling the upper hemisphere, two mobile installations, two twin cannons with circular shelling along the horizon and with vertical shelling angles upward 80 ', downward from the side 10'. The stock of shells for each cannon is 400 pieces;
• for shelling the lower hemisphere - two mobile installations for two twin guns with circular shelling along the horizon with vertical angles up + 3`, down 80`. The stock of shells for each cannon is 400 pieces;
• for shelling the rear hemisphere, a movable tail mount of two cannons with angles of shelling horizontally + 80` and vertically + 60`. Stock of 400 rounds per cannon. It was envisaged to install one or two 37 mm cannons on the aircraft.
The control of the cannon installations was remote and was carried out from sighting posts located in sealed cabins. The aircraft was provided with a central control post and aiming with several shooting points. To conduct aimed firing, the guns (from the upper, lower and stern points) were equipped with automatic synchronous collimator sights, providing firing up to 1200-1500 m. Automatic determination of the range was provided by radio range finders.
The normal bomb load of the aircraft was 10,000 kg. The maximum bomb load is 20,000 kg. Inside, the fuselage suspension provided a suspension of normal-load bombs with various caliber options. The holders of the internal and external suspension allowed the following basic bomb loading options: 1xFAB-10,000; 2xFAB-5000; 2xFAB-4000; 8xFAB-2000; 12xFAB-1000; 24xFAB-500; 40xFAB-250 or 70xFAB-100.
For targeted bombing, a complex sighting device is installed in the forward nose of the fuselage, consisting of a synchronous sight, a direction stabilizer, a heading sensor, connected to the pilot's MMC and an autopilot. The aircraft was provided with equipment with a radar installation, which ensured the execution of bombing from behind the clouds.
All crew members were subject to armor protection from being hit by fire from the rear hemisphere. Reservation of pilots provided protection for each pilot in the rear in a + 30 'cone from the longitudinal axis of the aircraft. The pilots and gunners were armored from below and from the sides, the arrows of the upper and lower cannon installations had additional armor at the rear (in the horizontal plane + 30 'and in the vertical plane, taking into account the angles of fire of the weapon). Reservation of navigators in combination with armor of pilots provided each of them in the working position with continuous protection from fire from the rear hemisphere in the + 30 'cone. The armor was designed to protect against shells from 25 mm cannons from a distance of 200 m. Thus, even in the early 1950s, the latest American jet fighters armed with large-caliber machine guns could not effectively repel the attacks of the Myasishchev strategists.
Increased attention was paid to the very design of the aircraft. The cockpits and the nose of the fuselage provided a good view of each pilot to the sides, up and straight ahead, up to 10 'below the horizon. Both pilots were provided with viewing through the upper and combat glazing of the cockpit, engines and landing gear of the aircraft, as well as viewing from behind the flying aircraft (when flying in formation). The glazed bow of the front pressurized cockpit provided the navigators with a full view in the front hemisphere. In the area of the working angles of the sight, the glazing did not give distortions and breaks.
The design of the airframe of the aircraft provided for the possibility of using it in transport and amphibious variants, while, after modifying the aircraft in the factory, it was provided:
• placement in the fuselage of a group of paratroopers up to 70 people, ensuring the ejection of the entire group within 15 seconds;
• loading oversized cargo into the fuselage, for which a door of 2350 mm in width and 2000 mm in height was provided (type C-47);
• external suspension of cargo axles;
• anti-hood angle, taking into account braking, was not less than 25 `at the maximum front operational alignment.
The design of the aircraft ensured quick and convenient dismantling, installation, testing and convenient operation of all equipment installed on the aircraft.
During the design period of the Air Force aircraft, gradually getting acquainted with real samples of Western aviation technology, as well as succumbing to information on the designed machines, they raised the bar of requirements for a new domestic bomber higher and higher. Therefore, it is not surprising that by the end of 1944, OKB-482 came to the conclusion that it was necessary to re-develop the project of a four-engine bomber with data exceeding the characteristics of the original project both in speed and range, and in bomb load. The new project received the code DVB-302.
The long-range high-altitude heavy bomber DVB-302 with powerful small arms, performing strategic bombing in distant rear areas, day and night, without fighter escort, became a further development of the DVB-202 project. Of the options for using the aircraft, unlike the previous project, only one option was worked out - a bomber. The creation and launch into serial production of the DVB-302 aircraft was supposed to mean a decisive step forward not only in aircraft construction, but also in a number of related industries. In accordance with the principles of V. M. Myasishchev, subject to the simultaneous and coordinated shift in all these industries, the creation of such an aircraft was quite possible, and represented no more difficulty than a complete copy of the B-29.
Several factors influenced the choice of the aircraft layout. It was originally supposed to place two 5000 kg bombs inside the bomb bay. However, this was not possible, since the location of the bombs next to or one above the other required a too large fuselage midsection, which adversely affected the mass and flight performance of the aircraft. The arrangement of the bombs one after the other entailed a too long cargo compartment, which is impossible both for design reasons and due to the large take-off centering when dropping one of the five-ton bombs. Therefore, it was decided to place only one five-ton bomb inside the fuselage. The size of this bomb was such that placing it inside the fuselage required the wing to be placed on top. Thus, at the selected load, the high-wing scheme turns out to be rational.
With this scheme, the horizontal tail in many flight modes fell into the wake from the engines and became less effective. In order to remove the horizontal tail from the wake jet, its transverse V was increased to 6`.
As on all four-engine aircraft, the size of the fuselage made it possible to have a firing point behind the tail. Therefore, the need for two-finned plumage disappeared, which led to the use of the usual single-finned plumage.
DVB-302 had a very significant specific wing loading. Therefore, a three-wheeled chassis was used to facilitate landing.
Since the aircraft must be equipped with pressurized cockpits, the cross-section of the fuselage was made round. The fuselage was a body of revolution with a slightly curved axis.
Several variants of DVB-302 with different engines were considered: ACh-31, AM-46, ASh-72. When developing the DVB-302 version with ACh-31 engines, it became clear that they were not powerful enough for an aircraft of this class and, in order to provide it with completely modern flight data, it was necessary to increase the engine power or design an aircraft of a completely different class for the ACh-31 engines that appeared. Mikulinsky AM-46s were still "raw" at that time and it was decided to install ASh-72TK in the final version. The takeoff power of the ASh-72TK engines was 4x2100 hp. with. The rated power of the engines is 4x1950 hp. with. The high altitude of the engines was ensured by the use of two turbochargers with intercooled air in air-to-air radiators. The presence of these units made it possible to maintain the rated power of the engine (1950 hp) up to an altitude of 9200 m.
The aircraft had very powerful armament. For shelling the upper hemisphere, two towers are installed on top of the fuselage, each having two 20 mm cannons; ammunition was 450-500 rounds for each gun. Angles of fire: circular fire on the horizon and 80`; up in a vertical plane. For shelling the lower hemisphere from the bottom of the fuselage, two of the same installations are installed, differing from the upper ones only in the removal of sleeves and links. Of these installations, one upper and one lower are located in the front pressurized cab, the other two in the middle cab. The units were separated from the inner space of the cabins by a hermetic casing.
The aircraft also had powerful artillery weapons in the tail boom. This armament consisted of one 23 mm cannon with 100 rounds of ammunition in one 20 mm cannon with 300 rounds of ammunition. The firing angles of this tower are 160 'horizontally and 50' up and down.
All installations had a remote control with an electric or hydraulic power drive and synchronous communication of the weapon with a collimator sight. Remote control freed the shooters from the great physical efforts that arise when controlling heavy weapons at high flight speeds, and the design of the control panels made it possible to select the speed of movement of the weapon in a wide range. The supply of weapons in all installations is continuous; descent - electric; recharge - electro-pneumatic. The installations are equipped with mechanisms for limiting the angles of rotation of the weapon and turning off firing in the dead zones.
In the process of designing power drives for controlling weapons, the issues of using a hydraulic and electrical system for this purpose were worked out. Both systems could provide all the requirements for mechanisms of this kind. Some of the advantages of the hydraulic system were the relatively lower weight and ease of manufacture of the actuators. In addition, the hydraulic system allowed the use of power mechanisms of any power without increasing the pump power, while in the electrical system this possibility is limited by the power of aircraft generators.
All installations were controlled remotely. Normally, both upper units were controlled by the shooter from the front cockpit, but, if necessary, he could also control the lower units. Under normal conditions, the lower installations were controlled by two gunners located in the rear cockpit along the sides and conducting observation and aiming through the side blisters. If necessary, any of these shooters could control the lower units, as well as the stern unit. The stern unit was controlled by the shooter, who was in the stern cabin. A second version of the aircraft's small arms was also developed, providing for two pressurized cabins with fire control at all points (except for the stern) from the front cockpit.
The development of an aircraft power supply system, shooting points controlled by special remote devices from sealed cabins and provided with sufficient visibility and convenience for the shooter, was a serious task, covering the work of not only aircraft designers, but also weapons designers, weapon installations, electric synchronizing servo installations. optically non-distorting glazing of lanterns, etc. But this task, taking into account the available samples of V-29, was quite solvable.
The bomb bay was designed with a large enough volume to accommodate bombs of all calibers from 100 to 5000 kg, which are in service with the Air Force. The total capacity of the cargo compartment is 9000 kg. The bomb bay could be loaded with bombs in the following variants:
• FAB-100x80 pcs. = 8000 kg;
• FAB-250x24 pcs. = 6000 kg (normal suspension);
• FAB-250x36 pcs. = 9000 kg (with additional hanging cassettes);
• FAB-500x16 pcs. = 8000 kg;
• FAB-1000x8 pcs. = 8000 kg;
• FAB-2000х4 pcs. = 8000 kg;
• FAB-5000x1 pcs. = 5000 kg.
The suspension of all calibers (except for the FAB-100) was carried out on the side latches introduced into the structure of the aircraft's power frames. The suspension of the FAB-100 was carried out using suspended cassettes mounted on power beams passing in the front of the cargo compartment. The layout of the cargo compartment provided a convenient passage to the bombs and bomb racks, the crew could view the compartment from the front and middle cockpits.
The total weight of the armor on the plane was 575 kg. Both pilots, navigator-bombardier and gunner in the aft cockpit were booked. The armor protected against 15 mm projectiles.
On the basis of the "302" bomber, a high-wing project with four AM-46 engines and other crew accommodation was also worked out, but the documents on it were not preserved in the reports.
Successful work on copying the B-29 reduced the Air Force's interest in the work of Myasishchev, and the closure of OKB-482 in 1946 automatically put an end to the DVB-202 and DVB-302 projects.
References:
Yakubovich N. Myasishchev. An inconvenient genius.
K. Udalov, V. Pogodin DVB-20.
DVB-202 // Almanac "Our Wings", Aviko-Press.
