Singapore Air Show

Aerospace

Trent 7000 for neo Makes First Runs

by Ian Goold
 - February 15, 2016, 11:00 AM
Rolls-Royce and Airbus expect to log about 120 hours’ flying over about nine months with the new 97,000-pound-thrust Trent XWB-97 engine for the stretched A350-1000 XWB on the airframe manufacturer’s A380 flying testbed.
Rolls-Royce and Airbus expect to log about 120 hours’ flying over about nine months with the new 97,000-pound-thrust Trent XWB-97 engine for the stretched A350-1000 XWB on the airframe manufacturer’s A380 flying testbed.

Rolls-Royce new Trent 7000  demonstrator unit made an “initial power run” for the first time about three months ago. The latest offering from R-R is the seventh member of the engine family and is destined to provide exclusive power for the Airbus A330neo (for “new engine option”) that is scheduled to enter service in 2017.

The demonstrator is being used to establish the key technical features of the engine, which combines experience from the A330’s current Trent 700, architecture from the Trent 1000-TEN (designed to power the Boeing 787-10), and technology from the Trent XWB, the manufacturer’s latest large civil engine.

The 68,000- to 72,000-pound-thrust Trent 7000 is planned to provide “significant” performance benefits, compared with the Trent 700, improving specific fuel consumption by 10 percent, doubling the bypass ratio and reducing noise by half.

To meet A330neo requirements, R-R (Stand N23) has adapted the Trent 1000-TEN to incorporate a new electronic engine control unit, new gearbox, air-start capability, and related changes. Before beginning series production, the manufacturer will assemble four development examples of the engine, which also sports a new nacelle and electronic bleed-air system that uses A350 technology.

The UK-based enginemaker recently celebrated a successful first 12 months of revenue passenger service with the 84,000-pound-thrust Trent XWB-84 engine on the first Airbus A350-900 XWB (for “extra wide body”) twin-aisle twinjet. The company claims that the milestone, reached in mid-January, was achieved “in an exemplary fashion” with a technical dispatch reliability rate of 99.83 percent. Thirty Trent XWBs entered service on newly delivered A350s during last year.

Airbus expects the first stretched A350-1000 airframe to enter final assembly line this month [February]. It is to be powered by the Trent XWB-97, now undergoing a nine-month, 120-hour flying program on an A380 testbed. The A350-1000 is planned to fly in the fourth quarter of the year, the schedule having slipped slightly from an earlier mid-2016 target, and to enter service about 12 months later, following certification work with three flight examples.

Testing of the Trent XWB-97, which is fitted at the A380’s No 2 (port-side, inboard) position, began with demonstration of a wide range of power settings at altitudes of up to 35,000 ft and evaluation of operability and handling qualities from low speed up to Mach 0.87. Other work includes high-temperature and icing-condition test campaigns, and confirmation of the engine-relight envelope, according to R-R head of Trent XWB marketing Tim Boddy.

Initial flights aimed at fine-tuning engine integration and “de-risking” the A350-1000’s early flight-test program. Later work is expected to concentrate on “maturity tests,” including further thermal-endurance and cyclic trials.

While testbed flying continues in France, R-R has focused on “industrialization” of the initial 84,000-pound-thrust Trent XWB-84 engine as it accelerates production for the A350-900. Boddy reports a “smooth transition” from XWB pre-production operations, with a new build line established at its Derby (UK) factory.

Before in-flight testing, the manufacturer had completed 150 hours of XWB-97 endurance testing, including 16+ hours at maximum take-off thrust and 42 hours at maximum continuous thrust. R-R has ground-run the XWB-97 at up to 99,000 pounds’ thrust after having earlier demonstrated 112,000 pounds’ thrust with an XWB-84 variant during “blade-out” testing.

It also completed XWB-97 icing and X-ray testing last year, with “good results” that provided grounds for “high confidence” of achieving performance targets, according to Boddy. R-R sees “huge synergies” between the parallel XWB-84 and -97 engine programs. “We need to gather certification evidence from bench- and flight-testing before the A350-1000 first flight,” said Boddy.

To meet Airbus assembly plans for about 10 aircraft a month, manufacture of Trent XWBs is being ramped up over about two years from 2.6 per week in late 2015 to 4.9 (including about one TXWB-97) a week before 2018. By next year, R-R expects to be building one XWB a day, the company having successfully achieved a parts-supply and production trial that saw “four engines assembled in four days.” Overall XWB production should reach 6.4/week by mid-2019, with monthly output comprising about 17 XWB-84s and around ten -97s.

Although production engines will not feature the technology until it has been “industrialized,” the XWB-97 is also the first R-R engine having a major additive-layer manufactured structure–the 1.5-m (around 60-inch)-diameter, titanium low- and intermediate-pressure compressor front-bearing housing.

R-R has dedicated Trent XWB-84 and -97 teams to translate testing lessons into powerplant maturity as production increases and the company develops service capabilities covering parts, spares, and training “to build inherent support.” Its venture into ALM has been driven by plans to improve Trent efficiency that also have contributed to major technology developments, including low-emission combustion systems, composite fan blades, and gearbox technologies that could appear on planned Advance and UltraFan engine programs.

Up to the beginning of this year, five XWB-97s – including the flying-testbed example – had been run, logging almost 1,000 hours and 1,500 cycles. Two further planned units include the seventh XWB-97 that incorporates fan and core modules from previous test engines.

Three units were in test, the third built (but the first -97 to run) having been used for rain and hail trials, after completion of system integration and “successful” large-bird ingestion. Two test engines also have been run at R-R’s Stennis facility in the U.S., one equipped to measure 2,000+ parameters of performance as the company sought to “gather as much telemetry as possible,” according to Boddy.

One XWB-97 continues in performance and fan testing (and is likely to remain so for several more months), including fan “flutter” and cross-wind trials. It also has been used in nacelle/thrust-reverser unit integration. Another was used for simulating typical flight cycles, which R-R has usually conducted in batches of 1,000 (but which Boddy suggested last year might not continue beyond about 600).