In March 1919 Polikarpov was selected as head of the technical department of the former Duks factory, soon to be renamed State Aviation Factory No.1 or GAZ No.1. In 1920, the first Soviet aircraft would be projected and built in GAZ No.1 and just three years later, it would already plan the construction of a multi-engine military aircraft known as 2B-L1 and powered by two 400 hp Liberty engines.
Nikolai Polikarpov’s construction activity was generally linked to fighters, but Polikarpov’s beginnings in aviation were directly linked to the Ilya Múromets bombers designed by Igor Sikorsky.
The development of this bomber began at GAZ No.1 in 1924 and the project was led by engineer L. D. Kolpakov-Miroshnichenko. Polikarpov had no relationship with the development of this project, since with the arrival of D. P. Grigorovich he would be excluded from the factory and transferred to the Glavnoavia aeronautical construction department. However, by the fall of that same year, after Grigorovich’s departure, Polikarpov would return to GAZ No.1 as head of the construction bureau. Once in this position he refused to take part in the construction of the 2B-L1 and acting as a consultant, he basically became a critic of the bomber.
The plane, however, began to be built. The VVS, foreseeing the possibility of practical use of the model, decided to replace the designation 2B-L1 with B-1, but it would soon become clear that the new bomber did not satisfy many of the requirements imposed by the military. This was the main reason why, even without finishing the B-1, it was decided to start working on a new bomber, which was called the B-2.
According to the requirements issued by the VVS management, the new bomber had to incorporate 3 to 4 Liberty engines. The B-2 should lift a weight of 1000 kg with an average speed of 170 km/h and transport it over a distance of 1000 km.
To meet this new requirement, the GAZ No.1 construction bureau developed six possible bomber variants:
- 4B-L3 – biplane with 4 Liberty engines and takeoff weight of 9 tons;
- 4B-L3 – biplane with 4 Liberty engines and takeoff weight of 10 tons;
- 4B-L3 – sesquiplane with 4 Liberty engines and takeoff weight of 11 tons;
- 3B-L3 – sesquiplane with 3 Liberty engines and takeoff weight of 9 tons;
- 3B-L3 – monoplane with 3 Liberty engines and takeoff weight of 8-9 tons;
- 4B-L3 – monoplane with 4 Liberty engines and takeoff weight of 10 tons.
Within this list were included projects by Polikarpov, Kolpakov-Miroshnichenko and Krylov.
Interest in these works remained between July and October 1925, but by this date it had already been decided to abandon the option of the Liberty engine, considering it lacking in perspective and to redesign the bombers with two 600-hp Wright Tornado North American engines.
As a basis for this new design, it was decided to use the French Farman Goliath bomber. Several of these aircraft had been acquired and arrived in Leningrad at the beginning of October.
To evaluate this foreign bomber and become familiar with its assembly, it was decided to send a group of specialists from GAZ No.1 to Leningrad. Polikarpov managed to ensure that neither Kolpakov-Miroshnichenko nor Krylov were included in this group, leaving the competition aside.
Already in the autumn of 1924 Polikarpov, head of the construction bureau and later head of the experimental department, had managed to establish a new, more effective system of work organization. The main objective of this new system was destined to gradually relegate the work of the old engineer-builders, accustomed to developing, approving and building their models based on their customs and points of view. The new structure of the OKB planned to use a system similar to the one adopted by A. N. Tupolev at the TsAGI, where a group of engineers defined the general concepts and then the different departments worked on the development of the components and systems.
The new B-2 bomber with two Wright Tornado engines, in its development stage began to be called GAZ No.1 2B-R2. The project began development in the spring of 1926.
Because the Wright Tornado engine had to be used in other types of devices, the possibility of buying a certain amount and then copying the model was valued, in the same way that this had been achieved with the Liberty.
The 2B-R2 was designed as a twin-engine biplane of mixed construction and was characterized by its bi-derived tail with double horizontal planes. The landing gear was of the conventional and fixed type.
Despite the great projection work carried out and the progress in the work, in April 1926 it was decided to cancel the VVS request for the 2B-R2 bomber. The main reason was the appearance of the all-metal Tupolev ANT-4 bomber, developed at TsAGI at the request of the Ostiexbyuró. The VVS management, pleased with the results of this new model, otherwise quite superior to the 2B-2R, decided to introduce it into service with the designation TB-1.
After a year and the appearance of some problems in the development of the TB-1 due to the lack of practice in the use of metal construction, it was decided to develop an alternative version of mixed construction. This job was assigned to Polikarpov’s collective and would be the basis for the TB-2 bomber.
2B-R2
Engines: Two 600 hp Wright Tornado
Empty weight: 5200 kg
Maximum takeoff weight: 9150 kg
Payload: 3950 kg
Maximum speed: 180 km/h
Practical ceiling: 4000 m
Bombload: 1500 kg
Accommodation: 5
All Aero 