Aviation of World War II
SDB. High-speed daytime bomber is a new type of front-line bomber. High speeds and high altitudes were supposed to provide him with the ability to deliver daytime bombing strikes against enemy targets without being accompanied by fighters. The Tu-2 was recognized as the most suitable as a base machine for the creation of such an aircraft.
"The aircraft" 103 "2 × AM-39, transferred for state tests to the 3rd department of the Institute, was comprehensively tested in 1941 with AM-37 engines. For example, in 1942 in Omsk the machine was converted to a single-wire power grid, and in 1943 the PFB-100 sight was tested on it. kind of changes and alterations. "
May 13, 1944 chief designer A.N. Tupolev appeals to the Deputy People's Commissar of the Aviation Industry A.S. Yakovlev:
“According to the personal order of the People's Commissar and your instructions, I modified the prototype“ 103 ”aircraft, on which the AM-39 engines were installed. This work is completed and the aircraft is ready for flight tests. I ask for your permission to take off the aircraft and carry out its tests. Appendix: Act of the Quality Department of the plant "156, Act of the motor race."
Permission has been granted. On May 21, 1944, the crew consisting of test pilot A.D. Flight and lead engineer B.N. Grozdova lifted the car on its first flight. By June 1, in 5 flights, factory flight tests were completed. On May 31, the aircraft was presented for joint tests at the SC NII VVS KA, and on June 1 it was transferred to the Chkalovsky airfield. From June 5 to July 6, the car successfully passed state tests.
In the conclusion of the Act of joint state and factory tests of an experienced high-speed day bomber (SDB) with two AM-39 engines (plane "103") it is stated: it in accordance with the model of the aircraft "63", approved on April 2, 1944 by the chief engineer of the Red Army Air Force and with the elimination of the defects indicated in the conclusions of this Act. " While the 63-1 aircraft was still undergoing tests, the OKB started to create the 63-2 aircraft.
Weapons. Two defensive 12.7 mm UBT machine guns and two 20 mm ShVAK cannons in the wing roots. Bomb load - 1000 kg, maximum - 3000 kg.
A.N. Tupolev had high hopes for the modified motors of A.A. Mikulin. Unfortunately, these hopes were not destined to come true.
The aircraft "63" 2 × AM-39F (SDB-2) was completed in pilot production at plant No. 156 in October 1944. The aircraft used the parts and assemblies of the latest production Tu-2 aircraft that had already passed combat operation.
From November 29 to April 4, 1945, fine-tuning tests of the 63-2 machine took place. They were carried out by Plant No. 156 in cooperation with the Air Force Research Institute. During the tests, the necessary changes were made to the aircraft:
To increase the directional stability, the vertical tail was installed increased, as on the latest production Tu-2 aircraft (with an area of 5.81 m & # 178; instead of 4.37 m & # 178;).
To facilitate the pilot's work, a new control of the water and oil cooler dampers has been performed.
To improve visibility, the pilot's flashlight has been redesigned.
A retractable step has been made on the aircraft to allow the crew to climb from the trailing edge of the center section.
To improve the navigator's working conditions, both in day and night flights, his cockpit was glazed in accordance with the approved layout.
The cameras installed on the "103" aircraft had a design defect, which was adopted by the NIRP for elimination in the series.
To improve braking, the air system is replaced by a hydraulic one.
To eliminate the ingress of too warm air into the cockpit, additional bulkheads have been introduced.
To eliminate the ingress of exhaust gases into the radiator tunnel, the relative position of the exhaust manifolds and the radiator inlet has been changed.
To shorten the filling time, the number of gas tanks has been reduced, and the cross-section of gas lines has been increased.
The drainage system is simplified, similar to the serial machine.
To ensure normal temperature conditions, the radiators of the additional circuit are increased, the inlets of the tunnels are improved.
The electric control of the R-10 propeller is replaced by a mechanical cable control, this is approved by the pilots.
After that, the car was transferred to state tests. They lasted from April 5 to May 16, 1945. The test report states:
Differences "63-2" from "63-1" : "Experimental AM-39F engines have been installed, the crew has been increased to 3 people, the armor protection of the crew has been installed, the supply of gasoline has been increased from 2150 liters to 2360 liters, simplified hydraulic and petrol systems, installed a new tail wheel with mechanical stopper control, changed the chassis - instead of the fork, a single rack was installed (only on this version), the horizontal tail was increased, the ShKAS machine guns were replaced with UBT and a number of others. "
The report noted that the aircraft significantly surpasses domestic and foreign aircraft of the same type, including the Mosquito, in terms of its flight data. A number of defects were also noted, the most serious of which was recognized as an insufficient overview of the navigator. The aircraft was not recommended for production, since the tests of the 68 (Tu-10) aircraft had already begun, from which they expected even better performance.
In May 1944, according to the proposal of A.N. Tupolev, the OKB proceeded to install PNB-4 radar equipment on the production aircraft Tu-2 No. 104 (produced in 1942 by the Omsk plant No. 166). The work was going fast enough. Already on May 27, 1944, a mock-up commission examined the placement of PNB-4 units on a Tu-2 aircraft. By the end of June, the experimental aircraft, which received the conditional code plane "104", was completed and on the night of July 2 was transported to the Chkalovskoye airfield, where the Scientific Research Institute of the Special Services of the Spacecraft was located. On July 18, 1944, test pilot A.D. The flight from the airfield of the Air Force Research Institute of the Air Force makes its first flight. As a leading engineer for testing special equipment of the aircraft "104" from the OKB A.N. Tupolev, L.L. Kerber. From August 10, 1944 to June 7, 1945, joint tests and refinements of radar equipment were carried out, at the end of which the aircraft was transferred to the Air Force Research Institute for State tests.
The plane "104" was tested with a flight weight of 9814 kg and had the following differences in relation to the serial Tu-2:
two VYa-23 guns were installed in the lower part of the fuselage in the cargo compartment; the drainage scheme in the detachable parts of the wing was changed; a heading machine is installed; a movable stabilizer is installed with an installation range on the ground from 0° to minus 4°; installed blocks of equipment PNB-4.
The installed PNB-4 equipment consisted of: a transmitter with a special antenna; the umformer feeding the transmitter; pilot indicator; receiver with selector and umformer; operator indicator; equipment control panel; two azimuth and two zenith antennas.
Station PNB-4 passed State tests on aircraft "104", but was not launched into series production, preference was given to the Gneiss-5s radar, which had similar data, but was ahead of PBN-4 in terms of development in the series. The very same plane "104" in 1946 was transferred to the OKB P.O. Sukhoi, where it was converted into a prototype of the UTB training bomber.