Tupolev Tu-334



The Tupolev Tu-334 (Туполев Ту-334) was a Russian short-to-medium range airliner project that was developed to replace the aging Tu-134s and Yak-42s in service around the world. The airframe was based on a shortened Tu-204 fuselage and a scaled-down version of that aircraft's wing. Unlike the Tu-204, however, the Tu-334 has a T-tail and engines mounted on the sides of the rear fuselage instead of under the wings. With the nationalisation of the Russian aircraft companies in 2009 to form United Aircraft Corporation it was decided not to continue with the programme.

Development
The Tupolev Design Bureau introduced the Tu-334 in early 1989 as an eventual propfan-powered airliner to potentially enter service for Aeroflot in 1995. However, it would have an interim turbofan-powered version that would begin airline service around 1991–1992. Consuming about 20 percent less fuel than the best Soviet turbofan, the propfan engine would be a then-unnamed geared powerplant from the Lotarev engine design bureau. The engine would have a thrust specific fuel consumption (TSFC) of 0.46 tsfc, resulting in a per-passenger aircraft fuel consumption rate of 13 g/km. The turbofan-powered version of the Tu-334 would use Lotarev D-436T engines with a TSFC of 0.62 tsfc and a bypass ratio of 6.5, and it would consume 20 g/km per passenger. The propfan Tu-334 would seat 104-137 passengers, compared with 86-102 passengers for the shorter, turbofan Tu-334.

Tupolev confirmed the use of the D-436 for the turbofan version shortly afterward. However, they initiated discussions with International Aero Engines (IAE) at the 1989 Paris Air Show to discuss using a 7500 kgf derated version of IAE's V2500 11345 kgf engine. The talks, which continued through at least the end of the year, were attributed to worries that the Lotarev could not meet Tupolev's timeline or fuel burn targets, or that Tupolev was canceling the propfan version. There was also concern that Tupolev could not meet Soviet state carrier Aeroflot's urgent capacity needs quick enough. In this scenario, the Soviet aircraft production ministry could allow the Yakovlev Design Bureau to compete and build the Yak-42M (a Yak-42 airliner derivative) because of its quicker availability, despite the ministry's assumed preference for the Tu-334.

Information about the propfan engine began to be revealed during the second quarter of 1990, although the details were often conflicting. In April 1990, while announcing the interim aircraft's service entry date of 1993, Tupolev's chief designer said that the ultrahigh bypass engine to be used would be a Lotarev (now renamed to the Progress design bureau) propfan resembling the General Electric GE36 UDF, and not the propfan it had been working on. However, the Central Institute of Aviation Motors (CIAM), a Soviet engine research institute, reported that Tupolev expected to have a propfan Tu-334 operating by the 1995-1997 period, probably using a geared propfan instead of gearless. Then a subsequent report named the Tu-334 propfan engine as the Lotarev D-27, a 3.8 m, 11.2 tf powerplant with a TSFC of 0.44 tsfc. The D-27 would also power the newly announced Yakovlev Yak-46 propfan airliner, which was similar to the Yak-42M competitor but used two propfans instead of three turbofans in the aft fuselage. Three weeks later, Tupolev said that government officials would decide shortly between two D-27 offshoot engines from the Progress design bureau for the final Tu-334 version in 1996: a Progress D-227 propfan, or a Progress D-527 "super contrafan," an ungeared but ducted contra-rotating powerplant with a bypass ratio of 18. Days earlier, the Soviet Union premiered a running propfan engine before Western audiences for the first time, flying an Ilyushin Il-76LL testbed aircraft with one installed Progress D-236 engine to the ILA Air Show in Hannover, Germany. Although the Soviets declined in Hannover to name the aircraft that would use the D-236, an October 1990 article named that geared engine as the powerplant for the final Tu-334 variant, which would compete against the D-27-powered Yak-46 for Aeroflot's Tu-134 replacement order.

Work commenced on the Tu-334 in the early 1990s, but proceeded slowly due to funding problems arising from the breakup of the Soviet Union. A prototype was displayed in 1995, but this was little more than a mockup with few systems installed. A functional aircraft first flew on 8 February 1999, and later that year, agreements were put in place for MiG to undertake part of the production of the airliner. A Russian type certificate was obtained – after some delay – on 30 December 2003.

Development remained slow due to protracted budget problems. In turn, the certification of the aircraft and its planned entry into serial production was delayed multiple times. As of December 2006 there were firm orders for the Tupolev Tu-334 from seven airlines, including Atlant-Soyuz Airlines and there were letters of intent from 24 airlines to obtain another 297 airplanes. The price per unit for the business version is estimated to be around $43–44 million.

One of the projected customers for the type was Iran. The Iran Aviation Industries Organization (IAIO) was in negotiations to purchase licenses to assemble the aircraft in Iran by 2011 and manufacture them completely by 2015 alongside the Tu-214. Nothing concrete became of these negotiations before the cancellation of the Tu-334 programme.

As late as 2008, Tupolev reported that a total of about 100 airlines had expressed an interest in placing orders for Tu-334s; on 31 July 2008, Tupolev Managing Director Sergei Ilyushenkov announced that production was targeted to begin no later than January 2009. However, this date also passed without any reported progress on Tu-334 serial production.

In 2009, with the project years behind the projected schedule and only two examples built and flying ten years after the first flight, the Tu-334 came under review during the rationalisation of the Russian aircraft companies, which led to the formation of United Aircraft Corporation. In mid-2009, the decision was taken to not continue with the Tu-334 programme and instead focus efforts on the Sukhoi Superjet 100, the Antonov An-148, and the Irkut MC-21.

Variants

 * Tu-334-100: Basic version, with accommodation for 72 passengers in mixed-class configuration (12 first-class and 60 tourist-class) or 102 passengers in high-density layout. Two 73.6 kN Progress D-436T1 turbofans.
 * Tu-334-100C: Proposed combi (passenger/freight) version of Tu-334-100.
 * Tu-334-100D: Planned stretched, extended-range version. Fuselage stretched by 54 cm and longer span (32.61 m) wing. Powered by two 80.4 kN Progress D-436T2 engines.
 * Tu-334-120: Planned derivative of Tu-334-100, powered by two 88.9 kN Rolls-Royce BR715-55 engines.
 * Tu-334-120D: Based on the Tu-334-100D, but with two Rolls-Royce BR-715-55 engines.
 * Tu-334C: Production cargo variant.
 * Tu-336: Proposed liquid natural gas-fueled version, with cryogenic fuel tanks above the passenger cabin.
 * Tu-354: Further stretched version, originally designated Tu-334-200. Stretched by 390 cm over Tu-334-100, with accommodation for up to 126 passengers. Powered by two Progress D-436T2 or Rolls-Royce BR-715-55 engines, the Tu-354's landing gear was strengthened to use four-wheel bogies.