Tupolev Tu-12
| Industry | Aerospace |
|---|---|
| Founded | 1922 |
| Headquarters | Moscow , Soviet Union |
The Tupolev Tu-12—also known by its developmental code Tu-77—was a Soviet experimental medium bomber powered by jet engines, evolved from the piston-driven Tupolev Tu-2 bomber following the conclusion of World War II. This aircraft served as a transitional model to help both Tupolev and the Soviet Air Forces (VVS) gain practical experience with jet bomber technology.
Development
In early 1947, the progress of the jet-powered bomber project Tupolev Tu-73 was delayed. To expedite the introduction of a jet bomber, Tupolev proposed modifying the existing Tu-2 medium bomber by installing British-made Rolls-Royce Nene jet engines. Although formal authorization to convert one Tu-2S in the OKB workshop and an additional five at Zavod (Factory) Nr. 23 was granted on 31 May 1947, work on the prototype—designated Tu-77 within the bureau—had already commenced in early May.[1]
To accelerate assembly, alterations from the original Tu-2 were kept to a minimum and included:[2]
- Replacement of the standard Shvetsov ASh-82FN radial engines with two Nene jet engines.
- Reduction of wing dihedral angle from 6° to 3°.
- Extension of the fuselage length by 400 mm (16 in) and an increase in rear fuselage height by 300 mm (12 in).
- Installation of a new tricycle-style Landing gear, with main gear retracting into engine nacelles.
- Addition of fuel tanks redesigned to accommodate a switch from gasoline to kerosene fuel.
- Modification of control systems including the addition of trim tabs on the elevators.
- Structural reinforcement of both wing and tail sections.
- Removal of 20 mm (0.79 in) ShVAK cannon from wing roots and installation of a single 23 mm (0.91 in) Nudelman-Suranov NS-23 cannon housed in an external fairing on the starboard nose side.
Testing and evaluation
The prototype reached completion in July and made its inaugural flight on 27 July 1947. Two units were exhibited during the Tushino Aviation Day parade held on 3 August 1947. Manufacturer's testing concluded in September, followed by state acceptance trials conducted from 4 October 1947 until 27 February 1948, at which point the aircraft was redesignated as the Tu-12. According to the NII VVS (Nauchno-Issledovatel'skiy Institut Voyenno-Vozdushnykh Sil – Air Force Scientific Test Institute) report, the Tu-12 differed from the Tu-2 by offering "a significant increase in speed, enhanced climb rate, and a higher operational ceiling, but exhibited reduced field performance and required substantially more fuel to maintain the same range as the Tu-2." Major issues identified included the absence of a pressurized cabin, which significantly impaired high-altitude operations, and the lack of deicing systems for both wing and tail leading edges as well as cockpit glazing. At elevated speeds, operating the manually controlled VUB-68 and Lu-68 gun turrets proved nearly impossible. Moreover, firing the NS-23 cannon caused severe vibration that rendered instruments in the navigator's compartment unusable and damaged the cabin glazing. Activation of the Identification friend or foe (IFF) system interfered negatively with both the intercom and radio communications. The original generators failed to supply sufficient electrical power, necessitating their replacement with higher-capacity units.
The NII VVS trials included simulated combat engagements between the Tu-12 and Soviet jet fighters such as the MiG-9 and Yak-23. These exercises proved invaluable for assessing fighter offensive weaponry, bomber defensive armament, and refining tactical approaches for both aircraft categories. Results highlighted the inadequacy of the existing 12.7 mm (0.50 in) defensive guns, leading to a policy that all future Soviet bombers would be equipped with power-operated turrets armed with 20 mm or larger caliber weapons.
Five factory-modified airframes were fitted with Klimov RD-45 engines—Soviet copies of the Rolls-Royce Nene—and all six completed aircraft were utilized by the VVS for crew training and familiarization purposes. Subsequently, these planes were reassigned to experimental roles: one served in drone testing while another, designated Tu-12LL, was outfitted with various pulse jet engines mounted on a pylon above its fuselage.
Operators
Specifications (Tu-12)
Notes
Bibliography
- Gordon, Yefim, and Vladimir Rigamant. OKB Tupolev: A History of the Design Bureau and its Aircraft. Hinckley, England: Midland Publishing, 2005. ISBN 1-85780-214-4.
- Gunston, Bill. The Osprey Encyclopedia of Russian Aircraft 1875–1995. London: Osprey, 1995a. ISBN 1-85532-405-9.
- Gunston, Bill. Tupolev Aircraft since 1922. Annapolis, Maryland: Naval Institute Press, 1995b. ISBN 1-55750-882-8.