Heavy Bomber First flight: 1931 Grigorovich

In the spring of 1930, practically without any traditional approvals or approvals, TsKB-39 received the task of designing a heavy bomber, which received the “proprietary” designation “Airplane No. 8” (TsKB No. 8), and in the Air Force - TB-5. Since Grigorovich was the eldest during the creation of the I-5, he remained so when performing the new work. The task itself appeared for a number of reasons. At that time, TsAGI was creating an all-metal TB-3, but its construction was delayed, and, moreover, due to a shortage of aluminum alloys, problems could arise with the mass production of the aircraft. Therefore, to be on the safe side, a machine of a similar purpose was required, the design of which would use more affordable materials.

According to the design, the TB-5 was a high-wing aircraft with a spaced vertical tail. The horizontal tail had an additional narrow plane that could be adjusted in flight, which was called a stabilizer. It was intended to reduce the effort on the control wheel during landing and when changing alignment.

At the beginning of the summer of 1931, TB-5 was taken to the airfield. After checks and adjustments, it was decided to release the car into the air. On June 30, pilot B. Buchgolts made the first test flight in the Khodynsky airfield area. Before the flight, concerns were expressed regarding the handling of such a heavy machine; everyone was particularly interested in how the stabilizer would behave. After landing, Buchholz dispelled fears, literally saying the following: “The stability in the air is good. The ease of controlling the aircraft is unprecedented. The loads on the rudders are very small.”

By July 20, the aircraft made 4 successful flights. With a mass of 11,200 kg and a fuel supply of 1,850 kg, the flight range was 1,100 km, duration - 6.7 hours at a cruising speed of 162 km/h at an altitude of 3,000 m. The maximum range with a full fuel load of 2,410 kg was 2,100 km. The flight weight is 12060 kg, of which 500 kg are bombs. The maximum speed was 180 km/h at the ground, the service ceiling was 3500 m, the takeoff run was 400-420 m.

In 1931, based on its design, the MDR-3 naval long-range reconnaissance aircraft ("Airplane No. 11") was created, which had the same wing, tail and a number of power elements. This seaplane, like the TB-5, did not receive development.

What about the Farmans? It turns out that the scheme used on the TB-5 lasted well until the outbreak of World War II. Several aircraft similar to the TB-5 saw action. The most distinguished was the specially built for long-distance passenger transportation NC-223-4 #2, which had its own name "Jules Verne". Mobilized for military service, this night bomber was the first among allied aircraft to carry out a night bombing of Berlin in 1940.

Armament. Three TUR-5 turrets with twin 7.62 mm DA machine guns, one coaxial 7.62 mm PV-1 machine gun; bomb load, 1,000 kg.

Photo	Description
	Drawing TB-5

Marine long-range reconnaissance aircraft First flight: 1932 Grigorovich

The MDR-3 project at the Central Design Bureau was designated No. 11. This aircraft was not sent into production, and yet it brought I.V. Chetverikov, and therefore aviation, had several innovative solutions. The project was supposed to use various design elements from the TB-5 bomber. According to its design, the MDR-3 was a boat seaplane with a high-mounted braced wing placed on the boat and a two-fin vertical tail with fins interconnected, as on the TB-5. The aircraft was equipped with two tandem power plants of four engines, just like on the TB-5.

Powerplant consisted of four BMW-VI engines in two tandems in the center section. The use of water-cooled engines entailed a significantly larger mass, but I.V. Chetverikov, the head of the maritime department and the author of the aircraft project, decided to go for it. The two engines had a common radiator under the front one. The installations were very easy to maintain. The gas tanks were riveted duralumin and were installed on racks above the wing center section on both sides of the boat in the plane of the spaced keels.

Construction of the aircraft began in the spring of 1931, and by November it was already built. In December, the aircraft was transported to Sevastopol, where on January 14, 1932, test pilot B.L. Buchholz made the first flight. Along with him on board the flying boat were mechanic A. Dneprov and the designer himself.

The aircraft showed good seaworthiness, speed up to 210 km/h, take-off time of 36 s, but poor rate of climb and a ceiling of only 3000 m. The reason for this was partly the tandem installation of engines, but most importantly - the deteriorated aerodynamics of the aircraft. Considering the long duration (8 hours) and range (1600 km) of the MDR-3 flight, as well as the urgent need of the fleet for such an aircraft, it was decided to continue work on it. The TsAGI Kosos team, headed by A.N., was entrusted with eliminating the shortcomings. Tupolev. There they did not modernize the car, but thoroughly redesigned it and got a completely different seaplane - ANT-27 (MDR-4). The new aircraft retained only the contours of the MDR-3 boat and became a three-engine cantilever high-wing aircraft with a single-fin vertical tail design.

Photo	Description
	Drawing MDR-3

Bibliography

• History of aircraft designs in the USSR, 1938-1950. /V.B. Shavrov/
• "Prison" bomber /Aviation and Time. Mikhail Maslov./
• Airplanes of Dmitry Grigorovich /Aviation and Cosmonautics. Mikhail Maslov./

04/07/2024.
By the way, after the creation of the I-5 fighter already at the end of May 1931, the OGPU board decided to release most of the “pests” ", including Grigorovich and Polikarpov. Polikarpov’s “capital punishment” was replaced with ten years in the camps, and then given a general amnesty, but without canceling the sentence. It was only annulled by the Supreme Court in 1956, “for lack of evidence of a crime,” 12 years after the death of the designer.
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