Tupolev '73'

Tupolev '73

Company type	Aircraft design project
Industry	Aerospace
Founded	Late 1940s
Founder	Tupolev design bureau
Products	Medium bomber aircraft (prototype)

The Tupolev '73 (samolyot 73) was a Soviet medium bomber featuring three jet engines, developed in the late 1940s. Ultimately, it was surpassed by the Ilyushin Il-28 'Beagle'.

Development

With the emergence of gas turbine engines, the Tupolev design bureau pursued advancements on the Tu-2 series. The Tupolev_Tu-8#Tu-8 (69) ('69') model was modified to incorporate two Rolls-Royce Nene I turbojets, replacing its original piston engines with new nacelle installations. This iteration received the internal designation 72 and was officially named Tu-18 2 × Nene I, but development ceased as resources shifted toward the more promising '73' project.

Adhering to the general layout of the Tu-2 through Tu-8 and '72', the initial version of the '73' short-range bomber—officially designated Tu-20 2 × Nene I—featured a shoulder-mounted wing, a large vertical stabilizer with an integrated dorsal fin, tricycle landing gear, and engines housed in elongated under-wing nacelles positioned roughly at one-third of the wingspan. These nacelles also contained the main landing gear when retracted. Prior to finalizing this design, it became evident that the Nene I engines delivered less thrust than anticipated—approximately 4,400 lbf (20,000 N) instead of the expected 5,004 lbf (22,260 N)—which necessitated adding a Rolls-Royce Derwent V booster engine mounted in the rear fuselage, exhausting at the base of the vertical tail.

The tri-motor configuration of the 73 (officially Tu-14 2 × Nene I + 1 × Derwent V) entered development after acceptance, achieving its maiden flight on 29 December 1947. Flight testing continued through 31 May 1949, yielding encouraging outcomes and leading to an order for ten pre-production 73S prototypes powered by Soviet-built equivalents of these engines—the RD-45 and RD-500 (domestically produced Nene and Derwent models). However, none of these prototypes were completed; components fabricated at GAZ-23 were later integrated into the production line for the Tupolev Tu-14 at GAZ-39.

Advancing from the '73' series, a photographic reconnaissance variant known as 73R or '78' (officially Tu-16 2 × Nene I + 1 × Derwent V) was developed. The '78' visually resembled the '73' except for a retractable conical shutter covering the rear fuselage Derwent engine intake located at the front of the dorsal fin fillet. Its first flight occurred on 7 May 1948, followed by trials of its photographic systems which proved unsatisfactory. Despite attempts to improve this equipment, on 14 May 1949, the Council of Ministers terminated all further work and production plans for the '73', '78', and '79' models.

Two additional reconnaissance projects resembling both '73' and '78' were designed but never progressed. The first 79 (officially Tu-30 2 × Nene I + 1 × Derwent V) did not advance beyond design stages. The second 79 (officially Tu-20 2 × VK-1 + 1 x RD-500) intended to utilize an incomplete '73S' airframe but was cancelled alongside other developments.

The Soviet Air Force (VVS - Voyenno-Vozdushnyye Sily) declined these tri-motor bombers due to their reluctance to operate aircraft with mixed engine types. Instead, they favored the Ilyushin Il-28 for medium bomber roles. Conversely, Soviet Naval Aviation (AV-MF - Aviatsiya Voyenno-Morskogo Flota) required a torpedo bomber and adapted it from the final version of the '73', designated as 81 (officially Tu-14 2 × VK-1), which was produced as the torpedo bomber variant 81T (officially Tu-14T 2 × VK-1). These aircraft entered service with AV-MF as the Tupolev Tu-14T.

Variants

Source: OKB Tupolev: A History of the Design Bureau and its Aircraft

'72'

Early concept for a tactical bomber equipped with a pair of Rolls-Royce Nene I turbojet engines, developed from the Tupolev '69' (Tu-8), which was never constructed.

Tu-18 2 x Nene I: designated official model name.

'73'

Preliminary design for a short-range bomber using two Rolls-Royce Nene I turbojets, which remained unbuilt.

Tu-20 2 x Nene I: official designation.

'73'

Experimental bomber design powered by two Rolls-Royce Nene I and one Rolls-Royce Derwent V turbojet engines; one unit was produced.

Tu-14 2 x Nene I + 1 x Derwent V: official model name.

'73S': Ten pre-production units were ordered but only partially completed before the project was terminated.

'73R': original OKB code for the '78' photographic reconnaissance variant.

'78'

Reconnaissance aircraft powered by Rolls-Royce engines, with one prototype built.

Tu-16 2 x Nene I + 1 x Derwent V: official designation.

'79'

Initial concept for a photo-reconnaissance aircraft based on the '73' model.

Tu-30 2 x Nene I + 1 x Derwent V: official designation.

'79'

The '78' variant fitted with Soviet-produced Klimov VK-1 engines, originally known as '73R'.

Tu-20 2 x VK-1 + 1 x RD-500: official designation.

'81'

Medium bomber developed from the '73', featuring twin engines.

Tu-14 2 x VK-1: official designation.

'81T'

Torpedo bomber variant derived from the '73', designed for the AV-MF naval aviation.

Tu-14T 2 x VK-1: official designation.