Opportunities DB-3 as a scout tried to expand the use of outboard cabin captain Gerasimov. The idea was simple : bomber carried under the fuselage airframe little bit of that , if necessary, fell down on a rope . It sat navigator observer . Originally this design was offered for four-engine TB-3 . Intelligence unit, according to the calculations of the author, allowed himself to hold higher bomber away from anti-aircraft guns . Plane could walk in the clouds, and the cabin under the edge of the cloud . From it could lead visual reconnaissance , photographing and aiming at bombing . Cabin under the TB-3 was actually built and tested . In 1938 he was given specification for the design options under the DB-3 . Design and construction of the plant number 115 charged by placing the term to February 1, 1939 This deadline was not sustained by the middle of 1940 the prototype still not completed until the end .
Cab was manufactured entirely of wood and looked like an airplane without wings . In the rear housed horizontal tail and rudder . In contrast to the first embodiment of the navigator sat in a fully enclosed cabin . He possessed major appliances , sight OPB -2 and contacted navigator carrier aircraft using VHF radio . It was assumed that he would sit in flight through the hatch arrow , which after the release of the cable on the 10-15 m cab pulled up under the hatch. Cabin went down under its own weight , the holding brake . Pulled up her winch actuated motorcycle engine PMZ 18 hp Winch controls an additional crew member . Cab turned out pretty easy - together with navigator , she weighed only 200 kg. According to calculations of the speed of the aircraft carrier in the cabin was released to fall to 54-66 km / h With a length of 600 m cable cabin was supposed to go to 200-250 m below the aircraft.