TB-4 (ANT-16)
TB-4 (ANT-16) - Program
On July 3, 1933, the crew of the pilot Gromov made the first flight of the aircraft, on the basis of which the pilot gave the following short evaluation to the aircraft: "... The take-off is simple, there is no tendency to turn. The takeoff is short. When climbing, the plane is stable and gaining the height is good. When flying - it is stable and easy to operate. While planning is stable and rearrangement of the stabilizer is almost not required.Seeting is very simple, there are no twists at the run ... ".
Excessive efforts were made on the steering wheel and pedals. As a result of the tests, the rudder was overcompensated. Efforts on the pedals first decreased to zero, and then increased, but with the opposite sign. Recommendations were developed to combat this.
In September 1933, the car entered the state testing. The crew included P. Stefanovsky, M. Nyukhtikov, L. Sheverdinsky and A. Ryazanov. The general impression of the testers about the new machine was positive.
However, TB-4 was difficult to manage with a rapid change in flight conditions, there was not enough efficiency of the elevator to land. In addition, the flights revealed that with the simultaneous shutdown of two engines on one of the planes, the aircraft has unacceptable fluctuations in the tail section of the fuselage. With a flight mass of 33 tons, the aircraft showed a top speed of only 200 km / h. Affected by the insufficient power of the power plant due to excessive rotation of the screws and a significant part of the thrust spent on blowing a thick wing.
On the tests of TB-4 were memories of Stefanovsky, on them one can judge the perception of the pilots of this machine: "... TB-4 forced to forget about both character and habits, he simply shook!" A man of average height walked freely, not only in the fuselage, but did not bend down in the central part of the wing either. a real small-sized power plant for the autonomous power supply of all aircraft units ... Various equipment, weapons, systems and control devices filled the entire interior of the plane of outlandish dimensions .M.M. Gromov, passing me a car, He spoke more than briefly: "It flies well, you will see."
The test program consisted of two main tasks: to reveal the maximum flight data of the aircraft, without cannon-machine-gun equipment, and then with fully supplied weapons. "... Thirty-five tons of metal and fuel made themselves felt immediately. The car ran off steeply. On takeoff, the helm did not have enough. Designers have the opportunity to make such a case. I nod to the second pilot Misha Nyukhtikov, he presses the button of the stabilizer's electrical device. The plane obediently breaks away from the strip. "On this ship with the stabilizer by hand you can not control at all. In terms of area, it is equal to the wing of a single-engine aircraft. Due to insufficient aerodynamic compensation, it is difficult to control such a vehicle, especially with a rapid change in the flight mode ... By using the electric control, the stabilizer resorted to landing, too, in order to squeeze the plane into three points. So it was supposed - the elevator was not enough here ... This time it was necessary to check the behavior of the aircraft with a switch-off at first one, then two of the six motors. The disabling of one for piloting the car had almost no effect. When the two were switched off immediately, and moreover on one side of the wing, strong oscillations appeared on the tail empennage. Experimented the second, third, fifth time - the same thing: oscillations arise completely unacceptable."
After this flight, VMPetlyakov and two more experts from the Design Bureau for Strength and Vibration were invited to the tests. The hot debate about "can shake, can not shake" ended in the flight of Petlyakov in the stern gunner's booth. Petliakov experienced all the "delights" of the strongest vibration on himself. The tests were terminated, the aircraft was sent for revision. Strengthened the tail of the fuselage, changed the adjustment of the elevator, and finally installed machine-gun towers on the wing, fully manned weapons. Soon, TB-4 again entered the Air Force Research Institute. Although further tests were more or less successful, to adopt the machine for service and to recommend it to the series, the military refused.
The reasons for this were as follows. With a wing span of 54 m, a length of 32 m, a height of 11.73 m, a wing area of 422 m2, during the tests of TB-4 with M-34 engines, the maximum speed at the ground was 200 km/h, the maximum speed at altitude 2000 m - 187.5 km / h, the climb time 2000 m was 33.32 minutes, the practical ceiling was 2750 m, to achieve it it took 84 minutes, the take-off distance was 800 m, the take-off required 36 seconds, from 4000 kg of bombs the aircraft had a range of 1000 km. All this was much lower than the requirements of the Air Force.
The tests did not satisfy the military. As a result, they noted that the poor flying qualities of the aircraft were due to the insufficient power of the propeller motor group, the aerodynamic design of the aircraft is good, the weight of the structure is too large, the capacity of the gasoline tanks is insufficient, the aircraft needed further work.
When building a stand-in and a standard of mass production it was necessary to install motors with reducers, extending the wing. And to achieve flight data: speed at an altitude of 4000 m - 240 km / h, the ceiling - 6000 m, range -1500 km.
In November 1933, the Chief of the Air Force of the RKKA Alksnis held a meeting on the results of the ANT-16 tests, which put an end to this project. The minutes of the meeting, in particular, stated: "... do not run an experimental airplane in a series, in view of the dissatisfaction of tactical and technical requirements, as a standard, take the military version of the Maxim Gorky airplane with eight M-34 engines and pass the experimental ANT-16 aircraft to TsAGI for joint tests with the SRI, for clarifying issues related to the construction of "Maxim Gorky ..."
All refinements and final debugging of TB-4 (ANT-16) OKB and the military were supposed to perform on its backup, which was to become the main aircraft for the series. As early as November 1931, based on the data on the experimental aircraft, TsAGI compiled requirements for the main production aircraft. According to them, the TB-4 was intended for the destruction and destruction of large military-industrial facilities in the enemy's rear.
It was supposed to reach a payload of 8250 kg (in overload -12250 kg), range - 1000 km, speed at an altitude of 3000 m - 215-220 km / h, time of climbing 3000 m - 12-15 min, practical ceiling - 5000 m, run-up - 250 m, mileage - 300 m, landing speed -100 km / h. Defensive weapons: two aircraft guns and ten machine guns.
The second TB-4 was planned to be built by April 1932, and to be put on trial by May of the same year. In view of the fact that the lead aircraft was designed as a standard for serial production, TsAGI considered it necessary to introduce a number of constructive changes into it. First of all, to increase the size of the bomb compartments, to install a suspended glazed cab for the bombardier, a bowed glass rotating tower for the front arrow, to provide for the possibility of rapid alteration of the bomber variant into a transport or passenger aircraft.
In December 1932, designers approved the model of the main aircraft with the above changes, in particular, with a glassed arrow bow and other design improvements. In August 1932, the construction of the backup ["doubler"] began. By January 1933, the technical readiness of the aircraft was 17%, and on July 2, TsAGI received an order to stop work on the aircraft and to transfer part of the units to the construction of Maxim Gorky.
On the basis of ANT-16 it was supposed to prepare several modifications. At the end of 1932 TsAGI decided to launch the 22 passenger version of ANT-16 into series production at the plant. It was planned that TsAGI would transfer all the documentation for the car to the plant - 22 five months before May 1933, whose management was categorically against such a blitz. Gradually, everything went into the usual framework: TsAGI took the main work on the first machine on itself and gradually, due to the ever increasing load of pilot production for new projects, the work came to naught.
By order of the chief of the Air Force, in March 1931, the creation of the aircraft TB-4bis, with a reduced bearing surface, was included in the TsAGI plan for 1932 and carried out studies on this topic throughout the year. In March 1932, on the basis of preliminary calculations, they came to the conclusion that the "old aircraft" should have a dimension roughly the same as the experimental ANT-16, that the design of the wing and fuselage spars should be made of chrome-molybdenum pipes and profiles, most of the nodes fuselage - welded. The chassis is designed like an experienced car. Sheathing - 2/3 of corrugated plywood and 1/3 of duralumin.
In 1932, the UVVS and TsAGI considered the application of steam turbine units (maximum power 6000 hp, operational - 4000 hp) to the ANT-16 with a drive for two screws. The boilers were to be installed in the ANT-16 center wing. Work on such an installation was conducted in KhAI. In 1933, the UVVS offered TsAGI to work out the possibility of transporting tanks or tankettes (such as T-18, or four T-27s, or two T-37s) in ANT-16 cargo ports. TsAGI did not fulfill the task, but until 1935 the institute carried out a large amount of scientific and experimental work on this subject.
Although the tests and debugging of the ANT-16 showed its futility, the issue of serial production was solved at the stage of designing and building a prototype in 1932 at the plant #22 in Fili. It was decided to send the plant a set of documentation for the car, but in 1933 due to the workload of the plant with other orders, they decided to transfer to the new plant No. 18 in Voronezh.
Plant No. 22 transferred all available aircraft drawings there, and the deadline for the transmission of TsAGI drawings was set for July 1934. Release of the first series of 40-50 cars was scheduled for 1935, with the first head aircraft to leave the plant in the first quarter of 1935. At the end of 1933 the entire program for ANT-16 was canceled. The team led by A.N. Tupolev continued work on the development of heavy multi-engine giants, having offered a number of projects, including the ANT-20 (initially as a heavy bomber), ANT-24, ANT-26.
Since 1932, TsAGI had already worked on a new giant bombardment. Originally it was submitted as a modification of TB-4, and under the same article was financed. Tupolev actually engaged in the creation of a new aircraft, which later became known as the ANT-20. In the VVS documents, it originally appeared as TB4-8M34R. Initially, such a machine in the plans did not exist. Unable to obtain the required flight data of the heavy bomber TB-4 (the main reason for this was the lack of suitable engines), A.N. Tupolev increased the size of the wing and added two more engines. Much of the project, the ANT-20 then moved on to "Maxim Gorky," and even the designation was reused. On January 17, 1933, the committee for the construction of Maxim Gorky issued a letter to TsAGI for the design and construction of a single specimen of ANT-20. Later in different papers this machine was usually called simply MG.
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