Aviation of World War II
Thanks to the installation of special units, this machine could carry a 45-36 type torpedo on an external sling (the first number is the caliber of the torpedo in centimeters, the second is the year it was put into service) with a warhead mass of 200 kg and a total mass of 940 kg. The equipment of the DB-3T aircraft made it possible to drop this torpedo using low or high-altitude torpedo throwing methods. In the first case, the 45-36-AN torpedo (low-altitude aviation) was dropped from a height of 30 m at a speed of approximately 320 km/h. It was impossible to drop a torpedo below or above this height, since in this case it could either break from hitting the water, or burrow deep into the depths. Low-altitude torpedo throwing provided the highest probability of hitting a sea target, but required a high level of crew training and the aircraft's excellent flight and maneuvering characteristics. During high-altitude torpedo throwing, the DB-3T aircraft dropped a 45-36-AV (high-altitude aviation) torpedo from a height of at least 300 m, after which it descended by parachute and, when splashed down, began to circulate in a vicious circle on the target's course. In addition to torpedo armament, DB-3T aircraft also had conventional bomber armament, which made it possible to use them as bombers and for laying mines. This aircraft was also used as a long-range naval reconnaissance aircraft.
The DB-3T aircraft adopted by the aviation of the USSR Navy became the first mass-produced Soviet torpedo bombers that fully met the requirements for them. On their technical basis in 1939-1940. organizationally, a new type of aviation of the Navy of the USSR was formed - mine-torpedo-carrying aviation, designed to destroy enemy ships with torpedoes and bombs, mine enemy fairways, and exits from naval bases.
However, the DB-3T aircraft could take off only from land airfields, the creation of which at that time, especially in the conditions of deployment of the Northern and Pacific fleets, was fraught with great difficulties. This circumstance determined the appearance at the beginning of 1938 of a new DB-3TP aircraft. It was a serial DB-3T mounted on the floats of the TB-1P aircraft. The design of the attachment of the floats to the aircraft ensured their quick replacement with a conventional wheeled landing gear. In connection with the appearance of new loads, typical for landing cases of a float hydroplane, spars and ribs of the wing, butt joints of the center section with the fuselage on the DB-3TP aircraft were strengthened compared to the land-based torpedo bomber DB-3T. In addition, the float version had on board special marine equipment (bottom anchor with bollard, anchor winch, etc.), which ensured the operation of the aircraft when it was based at sea. The armament of the DB-3TP was the same as that of the DB-3T aircraft.
Flight tests of the DB-3TP aircraft with two M-86 engines, carried out in the summer of 1938, showed that the installation of floats significantly reduced the speed of the new aircraft: with a normal flight weight of 7550 kg and a 45-35-AV torpedo, its maximum speed became equal to 343 km / h. Compared to the land machine, the rate of climb and flight range of the float aircraft deteriorated. However, even in this case, the flight tactical data of the aircraft fully complied with the requirements for it and were practically not inferior to those of the latest domestic boat seaplanes MDR-5 and MDR-6, which were undergoing flight tests at that time. According to the piloting technique, the new aircraft turned out to be quite simple and could be quickly mastered by medium-skilled pilots who had been trained on the KR-6P float reconnaissance aircraft.
“The aircraft is good as a torpedo bomber and high-speed naval bomber. It is fully consistent with these appointments, ”test pilot Sukhomlin assessed the machine. Test pilot Matveev gave the following review: “All the positive properties should also include the good strength of the aircraft, the strength of the structure is felt. Impressive machine. It is quite worthy to be in service with the aviation of the navy.
In conclusion, based on the results of state tests, it was noted that the DB-3TP aircraft can be recommended for adoption by naval aviation in the variants of a high-altitude and low-altitude torpedo launcher, a high-speed bomber and a long-range reconnaissance aircraft.
Nevertheless, this aircraft was not mass-produced. The complication of its operation in comparison with the land version, especially afloat, had its effect, when it became much more difficult to hang bombs, torpedoes, and maintain the aircraft's power plant. In addition, for the normal operation of such aircraft, it was required to have slipways, hangars, storage facilities for ammunition and fuel on the shore. Ultimately, the main efforts were focused on expanding the network of land airfields, and in a short time the problem of basing DB-3 aircraft was solved in all fleets.