The Tupolev '73', (samolyot 73), was a Soviet trijet medium bomber of the late 1940s. It lost out to the Ilyushin Il-28 'Beagle'.
The Tupolev OKB continued to develop the Tu-2 line with the advent of gas turbine power-plants. The Tu-8 ('69')was redesigned with two Rolls-Royce Nene I turbojet engines, replacing the piston engines in new nacelles. The new design was given the OKB designation '72' and official designation Tu-18 2 × Nene I, but was abandoned due to the more promising '73' design soaking up resources.
Following the general arrangement of the Tu-2- Tu-8, '72', the initial '73' short-range bomber (official designation; Tu-20 2 × Nene I) had a shoulder mounted wing, a large unswept fin and rudder with integral dorsal fin, tri-cycle undercarriage and engines in long under-slung nacelles at about 1/3 span, which also housed the main undercarriage legs, when retracted. Before the design was finalised it was discovered that the Nene I engines were producing less power than expected; and not the expected, necessitating the addition of a Rolls-Royce Derwent V booster engine in the rear fuselage, exhausting at the base of the fin.
The three-engined '73' (official designation; Tu-14 2 × Nene I + 1 × Derwent V) was accepted for development and the '73' first flew on 29 December 1947, with flight tests continuing until 31 May 1949, with promising results, resulting in a production order for ten '73S' pre-production prototypes, powered by RD-45 and RD-500 (Soviet production Nene and Derwent engines). None of the pre-production order were completed but parts manufactured at GAZ-23 were absorbed by the Tupolev Tu-14 production line at GAZ-39.
Further development of the '73' line resulted in the photo-reconnaissance '73R' / '78' (official designation; Tu-16 2 × Nene I + 1 × Derwent V). The '78' was outwardly identical to the '73' with the exception of a retractable conical shutter over the intake of the rear fuselage Derwent at the forward end of the dorsal fillet. The '78' first flew on 7 May 1948 and conducted flight trials of the photographic equipment, which were unsatisfactory. Improvements to the photographic equipment notwithstanding the Council of Ministers cancelled all further development or production of the '73', '78' and '79' on 14 May 1949.
Two more phot-recce projects were designed both similar to the '73' and '78'. The first '79' (official designation; Tu-30 2 × Nene I + 1 × Derwent V) was not proceeded with. The second '79' (official designation; Tu-20 2 × VK-1 + 1 x RD-500), was to have utilised an uncompleted '73S' airframe but development was cancelled as noted above.
The VVS (Voyenno-Vozdushnyye Sily - Soviet air force) rejected the three-engined bombers as they were averse to fielding aircraft with two engine types. They were also more in favour of the Ilyushin Il-28 for medium bomber roles. The AV-MF (Aviatsiya Voyenno-Morskogo Flota - naval aviation), however, were in need of a torpedo bomber which was developed from the final '73' iteration, the '81 (official designation; Tu-14 2 × VK-1) as the '81T' (official designation; Tu-14T 2 × VK-1). Production aircraft were delivered to the AV-MF as the Tupolev Tu-14T.[1]
Data from: OKB Tupolev: A History of the Design Bureau and its Aircraft[1]
. Bill Gunston. Tupolev Aircraft Since 1922. Naval Institute Press. Annapolis, Maryland. 1995 . 1-55750-882-8.