After five years of design studies, Avic has significantly revised the design of its MA700 turboprop airliner, which it has now launched into full-scale development with entry into service targeted at 2019.
Among the changes, Avic has added a shortened version with about 50 seats to the previous plan to follow the initial 78-seat version with a stretched variant accommodating “about 90.”
New details show the MA700's cabin width has shrunk during pre-development, with the manufacturer retreating from a plan for roomier seats than usual for such aircraft. Adoption of a narrower fuselage and shorter wing span than planned partly explain a reduction in what already looked like an aggressive weight target.
Bids from engine makers were due in June but the supplier still has not been chosen. It will be within a few months, says Dong, deputy chief designer of Avic's First Aircraft Institute, a design bureau. Proposed new engines from Pratt & Whitney Canada andare likely candidates. Suppliers of other systems will be chosen in the first half of 2014.
The status of the MA700 has been unclear for years, with officials sometimes saying it had been launched. Avic's press conference Dec. 19 confirmed that only now has that happened. About five years have been allocated to ready the aircraft for service; first flight is scheduled for 2016. The development cost will be several billion yuan (6.1 yuan = $1), says Geng Ruguang, deputy general manager of Avic. The preliminary design review is scheduled for 2014.
In May, first delivery was projected for 2018. Avic Aircraft, the large-airplane unit of Avic that is responsible for the program, still expects to receive airworthiness certification in that year. There are no launch orders, even though Avic says the program is being undertaken for profit.
The plan for a short version must mean the MA700 will replace the current Avic MA60 (and MA600 update), an Antonov An-24 derivative whose certification cannot be recognized by Western civil aviation agencies. Amid a general shift in demand toward larger regional airliners, there is not much requirement for small turboprops, however. Moreover, a 50-seat MA700 would suffer the usual weight penalties of a shortened commercial aircraft.
Avic is aiming for Western endorsement of the MA700's certification, as it is for most of its new aircraft. This will depend on Comac finalizing development of theregional jet, whose delayed certification, now due next year, is holding up recognition of Chinese airworthiness assessment.
Apart from modernity, the MA700 will differ from its competitors in size: It will be larger than theand , yet smaller than the new 90-seater being considered by owners and . The type will offer performance approaching the high level of the Q400 but, if Avic hits its targets, a weight per seat near the low level of the ATR 72. According to Avic, the MA700's advantages will include economy in fuel consumption and maintenance, adaptability to operation from hot-and-high airfields and those with unpaved runways and speed and, in the cabin, quietness, spacious overhead bins and comfort.
Despite a claim of spaciousness, it is evident the designers have pruned weight and drag by slimming the fuselage cross-section. Seat backs are now 44 cm (17.3 in.) wide, the same as in the ATR 72 and the Q400; last year Avic's published design showed 46-cm seat backs. And aisle width in the standard arrangement has fallen to 43.5 cm from 46 cm—a little less generous than the ATR 72's but roomier than the Q400's.
The result is that fuselage width has evidently shrunk by 10.5 cm to about 2.9 meters (9.5 ft.). Standing room in the aisle has risen 5 cm, however. The greater cabin height, narrower width and retention of an underfloor baggage compartment (shown by an official model) suggest Avic may have shifted from a circular cross-section to an egg-shaped one, like that adopted by designers of India's proposed RTA turboprop.
The MA700 span has been cut dramatically since last year's figures, by 1.7 meters to 27.5 meters, while length has risen more than 0.8 meters to 30.9 meters; the latter change is probably associated with a rise in standard seating from 76. The new standard seating of 78 assumes an all-economy arrangement at 81-cm pitch. Dong Jianhong says the longer aircraft will have more than 90 seats but a further stretch beyond 100 seats is not contemplated. Anything longer than the first stretch would presumably have inadequate takeoff rotation. Adding complete seat rows would presumably make the capacity 94 or 98.
Maximum cruise speed will be fairly high at 610 kph (380 mph), but that is at the low end of the range stated last year, 600-650 kph. Fast turboprop airliners are more popular with passengers and more flexible in operation, but more speed demands more power, weight and cost. Industry officials have said that the MA700's installed power will be determined by the need to climb fast enough from runways to minimize interference with jet operations; the maximum cruise speed is just a byproduct of that, with the normal cruise speed intended to be 500 kph. The generously low-power loading should also support the type's intended suitability for operation from hot-and-high airfields.
The power requirement is not stated but Dong says it is less than 5,000 kw (6,700 hp) for each engine, which is only to be expected for the aircraft's size. The 5,000-kw Avic Engine WJ-10 turboshaft, now under development, should eventually be a candidate, however, especially for high-powered military derivatives, but Dong says it has not been offered. The Chinese air force is said to want 50 MA700s. If those are intended to be government transports, then they could be operated by an airline instead, and Western companies could supply their engines, avionics and other equipment.
The changes to the MA700 over the past year or so are clearly aimed at cutting weight, drag and therefore manufacturing and operating costs. Industry officials said in May that empty and gross weights had fallen by 1 metric ton (2,205 lb.), even though earlier targets were already well below the weights of the Q400, which seats 74 at 79-cm pitch. The MA700's empty weight target of 14.5 tons compares with the 17.7 tons of the Q400, though it is possible that Avic's figure excludes items usually counted in the operational empty mass.
If Avic achieves its goals, empty weight will be 186 kg per passenger seat, about the same as the operational empty weight per passenger of the ATR 72, which has very low power, a maximum cruise speed of just 510 kph and a composite wing. Moreover, the ATR 72 has the weight advantages of a stretched version, whereas the MA700 in its initial offering should be carrying the weight of design provisions for a longer fuselage.
MA700 range with 78 passengers will be 1,700 km (1,060 mi.), but Avic says the type is “positioned” for 800-km routes. It will use fly-by-wire flight controls. The aircraft will be designed for a life of 60,000 flight hours or 60,000 flights, equivalent to 20 years of operation, industry officials have said.
The MA700 will be made mainly of conventional aerospace aluminum, like its competitors, says Dong. It will not have a composite wing. Composite material will probably be less than 10% and the composite fiber will be of T800 grade, which is now in production in China (AW&ST Dec. 9, p. 32).
When the MA700 was revealed as a proposal in 2008, it was supposed to go into service in 2014. Slow progress in propulsion studies have caused delays, an industry official says. More recently, financing has slowed things down, says another. This is a commercial program for Avic. Unlike theprogram, it is not being funded by the central government, although Geng says local governments may contribute.
|MA700 Design Evolution|
|April 2012||Dec. 2013|
|Empty weight||15.5 metric tons||14.5 metric tons*|
|Max payload||8.6 metric tons|
|Fuel||5.5 metric tons|
|Max takeoff weight||27.5 metric tons||26.5 metric tons|
|Max cruise speed||600-650 kph||610 kph|
|Design cruise speed||500 kph*|
|Power||Less than 5,000 kw x 2|
|Ceiling, one engine out||5,400 meters|
|Takeoff distance||1,400 meters|
|Landing distance||1,200 meters|
|Range, normal pax||1,700 km|
|Range, max payload||1,100 meters|
|Span||29.2 meters||27.5 meters|
|Length||30.06 meters||30.9 meters|
|Track||4.1 meters||4.1 meters|
|Wheel base||11.2 meters|
|Cabin width||2.7 meters||2.618 meters|
|Seat back width||0.46 meters||0.44 meters|
|Aisle width||0.46 meters||0.435 meters|
|Aisle height||1.95 meters||2 meters|
|Composite content||About 15%||No more than 10%|
|Blanks indicate data unavailable.|
|Metric ton = 2,205 lb.; kph = 0.62 mph; km = 0.62 mi.; meter = 3.28 ft.; kw = 1.34 hp.|
|Source: Avic, except *industry officials in April 2013.|