Development of Mitsubishi Aircraft’s MRJ regional jet continues on schedule, as some 800 engineers, designers and subcontractors in Nagoya, Japan, work to complete the project’s critical design review by the end of this year. Finished with the project’s preliminary design review in April, the engineering team aims to ready the first of four MRJ90 prototypes for first flight near the end of 2011. Development of the 70- to 80-seat MRJ70 lags its larger sibling by roughly a year, according to Mitsubishi Aircraft executive vice president Junichi Miyakawa.
Holding a firm order for 25 MRJ90s from Japan’s All Nippon Airways, Mitsubishi plans to deliver the first of the batch in 2013. Miyakawa reported that engineers have frozen the design of the outer mold line and decided on the sizing of the major structural elements of the MRJ, based on aerodynamic loads taken from wind-tunnel testing. He explained that Mitsubishi has completed its evaluation of the structure and systems interface in one of the most complicated parts of the airplane–the nose section–to define maintainability, accessibility and manufacturing processes. The company has also completed the definition of the engine-pylon interface, another particularly complex part of the aircraft in terms of parts integration and loads, according to Miyakawa.
Meanwhile, Mitsubishi Aircraft has begun canvassing the convention and airshow circuit with a partial cabin mockup featuring slim-profile seats supplied by Japan’s Delta Kogyo, the company perhaps best known for the seats it manufactures for Mazda automobiles. Rather than urethane, Delta Kogyo’s 3-D net seats use fibers woven into three-dimensional structures that act as small springs and dampers. The approach results in thinner yet stronger seats, according to Mitsubishi. The design also features seat pockets positioned in the upper half of the seatbacks, adding to the legroom afforded by the thinner seats.
Capitalized at 100 billion yen ($1 billion), Mitsubishi Aircraft counts as minority partners Toyota, Mitsubishi Corp., Mitsui & Company, Sumitomo, Tokio Marine Nichido, JGC, Mitsubishi Electric, Mitsubishi Rayon and the Development Bank of Japan. Majority shareholder Mitsubishi Heavy Industries controls 64 percent of the company. A major partner with Boeing on the 787’s all-composite wing box, MHI brings considerable experience with the technology to the MRJ, whose design includes composite wings and mostly composite empennage, together accounting for about 30 percent of the aircraft by weight.
Powered by a pair of 17,000-pound-thrust Pratt & Whitney PW1000G geared turbofans mounted under the wings, the standard MRJ90 will fly a “typical” range of 1,200 nm with 92 passengers at a cruise speed of Mach 0.78 and a takeoff field length of 4,790 feet. While carrying 76 passengers, the MRJ70 would fly as far as 1,080 nm and require a takeoff field length of 4,560 feet. Mitsubishi lists three maximum takeoff weights for each airplane, ranging from 81,200 pounds in the standard MRJ70 to 94,400 pounds in the MRJ90LR.
“It was a tough decision for us to make,” said Miyakawa, referring to the choice of the still largely unproven geared turbofan design. “We had a good proposal from every engine company. The reason we chose the Pratt & Whitney engine was simply its game-changing performance and fuel burn, which perfectly fits with our product concept.” According to Mitsubishi, both the MRJ70 and MRJ90 will use 21 percent less fuel per seat on a 400-nm trip than the comparably sized jets now produced by Embraer. At least half of that benefit would come from the engines.
“Of course, it has new technology, so we really had to evaluate the risk involved,” added Miyakawa. “Mitsubishi’s engine division has talented engineers, so we had the resources to evaluate the engineering risk. But, of course, the Pratt & Whitney engine went through all the flight testing [with the geared turbofan demonstrator], so I’m so glad that our engineers were right.”
Although Mitsubishi could conceivably stretch the airplane to carry more than 100 passengers with the existing engines, that won’t happen, said Miyakawa, because its potential customers do not want to incur the costs associated with a third flight attendant, particularly given the limited stretch potential of the MRJ. “We are very much confident in the combination we have at this point,” he said. “Suppose you stretch the MRJ; I told you the engineering potential is 112. But major airlines, which have a regulation that says you need one flight attendant for every 50 passengers, they’re not interested in an airplane with 110 seats. They’re more interested in 120 or as many as 130, and this product does not cover that range.”
Mitsubishi Aircraft director of sales and marketing Yugo Fukuhara added that the company sees two major replacement markets for the MRJ–first, primarily in Europe, for old, thirsty regional jets such as the Fokker 100 and BAe 146, and second, for 50-seat jets now falling out of favor in the U.S. Unlike Bombardier with its C Series and to a lesser degree Sukhoi with its Superjet, Mitsubishi does not harbor ambitions to encroach on the territory held by Boeing and Airbus. “Still, we have a lot of constraints in the pilot scope clauses in the U.S.,” added Fukuhara.
Notwithstanding its purely regional airline pedigree, the MRJ would use Rockwell Collins avionics “equivalent to the [suite] used on the 787,” said Miyakawa. Other suppliers include risk-sharing partner Sumitomo Precision (landing gear), Parker Aerospace (hydraulic systems), Spirit Aerosystems (engine pylons), Hamilton Sundstrand (APU, electrical power and air management systems) and Nabtesco (flight control actuators). This past January Taiwan’s AIDC agreed to design and build the airplane’s slats, flaps, belly fairings, rudder and elevators.