Myasishchev Molot - M-6
From the outset, works in the DB-23 chief designer decided to thorough processing of many aspects of the design in a particular production base, which was inherited from the mass production of the Tu-4. Requiring a fundamental change in many processes both in terms of manufacturing technology and assembly, and in accordance with the new aircraft concepts at all.
As for the bomber, its overall layout scheme has been changed radically. According to the results of long TsAGI aerodynamic research was decided: to ensure the flight range of 12,000 km increase the aerodynamic efficiency of the aircraft. In this regard, a reduced sweep of the wing, as well as newer vysokonesuschie applied profiles. Following the example of the successful layout of the Tu-16 chief designer of OKB-23 LL Selyakov proposed to use a similar layout engines in the wing root bypassing longitudinal force elements on top of center and dropped sparok THD. Construction height horizontal engine package was substantially less than the thickness of the root portion of the wing compared to the same ratio in the prototype (Tu-16).
This made it possible to carry out pair of wing and fuselage more smoothly, without deep steps. The gas jets were "washed out" in the narrow beams that allowed to form the so-called "active" fairings joint body-wing, which for mitigating interference flows were more effective than single turbojet jet bomber Tupolev. Under identical redesigns bombers passenger planes nizkoplan scheme again flatter speed streams of gases from the nozzles four THD (on M-6P) would also be more effective in reducing interference resistance compared with the output streams from the Tu-104. To protect the fuselage from the heat exhaust gases next to the sides of their engine nozzles got deep undercuts shells on top and lowered in order to increase gas flow and reducing their temperature fields due to erosion but vertically.
Reducing the wing sweep was due to an increase aerodynamic efficiency through new experiments, according to which the highest values correspond to sweep 33-35° to the line foci within wide limits but the angle of attack and at speeds that are acceptable for transonic steady flight. For a wing M-4 was selected sweep angle of 35° to the line 0.25% chords. Devoid of pylons with gondolas TRD wing was aerodynamically clean, and only auxiliary landing gear fairings, working against further flutter remained there as extensions. They brought up the wing tips and increased transverse dimension of the aircraft, but it reduced the induced drag of the wing, working as endplates.
The actual construction of the aircraft and engine characteristics consumables AM FOR, of course, could not heavier bomber compared with the project. Designers had to once again increase the area of the wing to 326.35 m ˛, and for flexural-torsional rigidity throughout strengthen it while reducing the constriction. Similarly, units have been redone and empennage. For a given flight distance required to increase the supply of fuel, therefore, besides increasing the capacity of wing tanks, the fuselage was lengthened by more than 4 meters to ensure equality of loads on the landing gear was extended its base.
After analyzing the dynamics of motion but the runway identified by the results of the flight operations of other machines with bike rack, measures were taken to improve the sustainability bomber taxiing, landing and take-off especially when the speed and weight of the M-4 should be the greatest. This was facilitated by placing side landing gear on maximum possible distance from the bogie chassis and the center of gravity of the aircraft than the machine ensure retention of yaw on the runway during takeoff and landing.
After the final assembly of the aircraft and its systems ground debugging maximum takeoff weight of the M-4 was more than 180 tons, compared to the estimated mass of the project "1M", equal to 155 tons of its first flight took place on January 20, 1953 (B-52 flew 15 April, 1952 g .). Despite the creation of a strategic bomber for two months before the deadline (from the beginning of construction work to M-4 Stalin gave Myasishcheva two years), failed to reach any given flight distance (12,000 km) or larger than America, with its B-52 bombers. Nevertheless, the M-4 started into production with a commitment in the near future to get the project range and achieve real parity in competition with the United States.
Improving the machine was not so interesting thing for designers, as its creation, as there is nothing worse than to catch up ... Economical engines AA Mikulin then left much to be desired, so the chief designer of OKB-23 almost from the beginning of the works did not miss mind the state of affairs on Turbofan Engine VA Dobrynin VD-7. As the release of the first test and prototypes of these turbofan Myasischev strongly oriented to use them for their bomber. Bench until the first instance claimed conditionally and gradually began to make advances regarding its reliability, airplane people unfurled design and construction of new sections of the wing center section and motor gondolas.
Dimensions of the new "engines" forced relink central monoblock (or, as it was also called "cross"), which the assembly was completed independently and appeared in the completion of work on it in the form of a huge assembly unit: the middle part of the fuselage length of 23 m with a center-wing sweep 20m Everything for the final aircraft assembly attaches to this "cross", was also upgraded to a considerable extent. The forward fuselage was lengthened and rearrange almost a meter, wing, once again increased in size and the area again received an update profiling and were spared from recent fractures on the trailing edge.
Considering the number of design changes the tail part of the body, superstructure and eliminate cross-V regulator can with certainty say that compared to the previous standard model M-4 bomber redone with new engines VD-7 was actually a new type designation and received another "ZM 'or M-6. At the time of the machine for a full set of flight tests of the power plant could be obtained. VD-7 was still "raw" engine, and works reliably turbofan having stable characteristics and traction on turns, could be counted on the fingers.
Therefore, the first plane to the second series of the M-4 201 number given to the full weight of the aircraft by a new in design and device components and systems was equipped with a forced temporary composite propulsion motors of different types. The left pair of generality because of automation and fuel systems was presented engines AM-ZM, and the right pair is on the same grounds consisted of VD-7. Both power groups were adjusted for jet-powered identical to the values corresponding to the adequacy of the control levers in the cockpit and switch-on the digital display instrument panels pilots. We must pay tribute to the ingenuity Myasishchev accepting the extraordinary decision to expedite the preparation of the first flying machine "ZM" to factory tests. The first flight of a new model of strategic bomber M-6 was held March 27, 1956 By the beginning of serial production of M-6 with four HP-7B had "coming up" new improvements on the aircraft as a whole, the implementation of which has led to the release of the latest production series aircraft "DEC".
With the DM, flap areas were increased (by 6.9 square meters) and wings by 5.75 square meters due to the straightening of the trailing edge in the flap area. At the same time, the fuselage was shortened by a meter and the layout of the fuel tanks in the rear part was changed. "DM" - an understudy of the aircraft "M", actually became the standard for mass production of the M-4. The car was fully equipped with electronic equipment. It included radio stations: a liaison 1-RSB-70M, command RSIU-3M, an intercom SPU-10, an automatic radio compass ARK-5, radar sights RPB-4 "Rubidium-MM2" in the bow and PRS-1 "Argon" at the feed shooter, transponder SRO-1 “Barium”, marker radio receiver MPP-48, radio altimeters of large and small heights RV-2 and RV-17. The pilot plane "DM" was autopilot AP-5, and on production vehicles - AP-15. Aiming station PS-48, an optical sight OPB-11r for bombing and aerial cameras were installed on the aircraft.
Factory flight tests of "DM" No. 0003 began on April 1, 1954. The first flight on it was made by the crew of test pilot F.F. The case (co-pilot B.K. Galitsky, navigator M.S. Kharitonov). The remaining flights under the factory flight test program were performed by the crew of pilot B.K. Galitsky (co-pilot M.A. Pronin, navigator M.S. Kharitonov). During the tests performed 32 flights. It took almost a year. It took a long time to fine-tune and test the PS-48 sighting station, as a result, it was decided to replace it with the PS-53 with the VB-53 computing unit.