Cargo Kings: new Boeing 777F and 747-8F programmes

^{Guy Norris / Seattle}

It is a juicy target: $155 billion over the next 20 years. That is Boeing’s forecast for the value of new factory-built freighters as part of the continuing growth of the air cargo market, which it expects to triple over the next two decades.

“Our goal, and our hope, is to maintain our leadership in the freighter industry,” says regional cargo marketing director Tom Crabtree, who adds that Boeing provides more than 90% of the world’s freighter aircraft capacity, of which over 50% is provided by the 747 Freighter family alone. Overall, it estimates that there are 399 747Fs, plus 421 other Boeing widebody cargo aircraft in service or on firm order. Sixty 747 Freighters are on firm backlog, including 18 new -8Fs.

While the vast majority of the 2,872 new freighters Boeing says will be required by 2024 will be conversions, a sizeable fleet of around 724 is forecast to be new-build aircraft. Of these, the bulk will be in the large freight category over 65t, with the 777F and the 747-8F in the frame to compete against the Airbus widebody family for an estimated requirement for 520 new aircraft. Boeing expects the A380-800F to be joined by a potential A340-based freighter project, while the A300/310 and A330 freighters will continue to compete aggressively in the 40-65t category.

Overall, Boeing believes the freighter fleet will grow to around 3,526 over the next two decades. “Historically, 75% of freighters are conversions,” says Crabtree, who believes the same forces that will keep the 747-400F/ERF line busy into 2009 will continue building behind the 777F and 747-8F. “We have less than five open positions on the 747-400 and when we deliver the first -8Fs we will not deliver any more -400Fs,” says 747 vice-president and programme manager Jeff Peace.

Yet with acquisition costs in excess of $100 million, at least three times that of a conversion, the question remains: “Why would I ever want to buy a new one?” Crabtree says: “The answer is better cashflow up front, lower maintenance outlay, more revenue generation capability, more freight capacity and more range.There are a number of things you have to weigh in the business model.”

Better utilisation

Crabtree adds that a new-build 747-400F has on average a 10% better utilisation rate per year than a converted late 1990s-vintage 747-200. “For like build years, the numbers tend to hold up. In studies we saw a -200 conversion perform around 3,000h/year, for example, while the factory-built airframe will get 3,300-plus hours and equivalent cycles.” Airframe age, per se, is not necessarily the cause of the differences, but rather the purpose-built freighter carries less “systems baggage”, has less corrosion issues related to original galley/lavatory locations and “to a smaller degree the fact the new-build 747s have a nose door, so have better turn times”, he says.

First off the blocks in the new freighter family will be the 777F, which was launched in May 2005 on the back of the newly available 777-200LR airframe/engine combination. The aircraft, which offers a 103.9t (229,000lb) revenue payload capability, is the longest-range twin-engined freighter ever developed and – like its passenger siblings – has a 21-35% fuel burn per tonne advantage over the current trijet and quad-jet alternatives.

With 23 firm orders from Air France, the Avion Group, Air Canada and Emirates, the first aircraft is due to enter production in late 2007, with the start of wing spar assembly. First flight is due in the second quarter of 2008 with first delivery before year-end.

Firm configuration is to be completed in June when the fifth working group meeting is scheduled to take place. “Now is the time to increase the engineering head count,” says 777 programme vice-president and programme manager Lars Andersen, who adds: “It’s the first time a large group of airlines have been in on the ground floor to make sure the 747-8 and 777F are capitalising on operational experience.”

The group has had a direct impact on the 777F design in several ways, including the main deck cargo door, which has been widened to 3.71m (146in) to allow the largest 777 engines to be loaded in on a pallet. The working group has also been influential on smaller details such as the interaction of the cargo door with existing cargo-loading equipment. Andersen says that, for example, “they asked us to look at a way of opening the door that didn’t require many movements of the cargo loader”.

The loaders have railings and, with the expansion of the door to a geater width than in the 747, the door no longer fits within these limits. The door opening sequence therefore potentially carries the risk of interference with the loader, “so what we are looking at is a remote opening system with a video view, though we have not got agreement on it yet”.

Camera location

The cameras will be mounted in the same location in the leading edge of the horizontal stabiliser as the ground manoeuvring cameras in the 777-300ER. “We should be able to catch a view of the door and say it’s okay to open and close, and we can command that door from the [left forward] door.”

Boeing also hopes to reduce the aircraft’s weight by adding manoeuvre load alleviation to the flight-control system (FCS). “We are taking weight out of the wing by using the control surfaces to move wing loading at critical conditions inboard,” says Andersen. “We could take 300-400lb [135-180kg] of weight out of the aircraft by incorporating this into the flight-control system,” he adds, saying that, by transferring wing loading inboard, the outboard structure can be lightened.

Although some minor FCS rigging changes are required, the main modifications are in the software, which will be tested in forthcoming flight tests on a leased 777-200ER. The aircraft, which has most recently been used for risk-reduction work on the 787 flight-control laws, will also be used to assess a wider centre of gravity range. “As part of the design, we’re opening up the centre-of-gravity range to around 6%, and minimising the attention they will have to pay to that,” says Andersen.

Capable of carrying up to 27 pallets on the main deck, with up to 3m (10ft)-high loads, as well as 10 smaller pallets in the forward and aft lower lobes, the 777F can reach destinations such as Tel Aviv and Lagos from Montreal with a full payload and 85% annual winds, or under the same conditions can carry a maximum load from Paris to Seoul or Vancouver. With lower density payloads of 81.5t, the aircraft can travel direct from Paris to destinations as far afield as Manila, Singapore or Lima.

The engine will be offered as standard with the 110,000lb-thrust (489kN) General Electric GE90-110B1 engines. The -777F will also be offered with the -200LR’s higher-thrust -115B1 as an option. “We are designing it to use both, and if someone needs the 115,000lb-thrust engine, we have the capability,” Andersen says.

Design work on the 747-8 family, meanwhile, is also working towards a firm configuration around September, with major assembly due to begin in the first quarter of 2008, and first flight of the freighter expected around the end of that year. The 747-8F is due to enter service in the third quarter of 2009, with Cargolux the likely launch customer, while the passenger 747-8 Intercontinental is aimed at service entry in mid-2010.

“It’s the first time we’ve launched a programme beginning with the freighter version,” says Peace. “We expect to get the first Intercontinental order sometime this year, and more than one order by the end of the year. We won’t talk about who will ‘pop’ just yet because obviously those discussions are pretty sensitive,” he adds.

Windtunnel testing

The latest round of windtunnel testing has just been completed. This included high- and low-speed tests and fine-tuning of the noise characteristics on the fully integrated airframe, says Boeing. High-speed testing was performed at the company’s transonic windtunnel in Seattle using a 3%-scale model. Slow-speed and noise testing was completed in the UK at the Qinetiq Low Speed Acoustic Facility (LSAF) at Farnborough. “We are coming off these windtunnel tests, and getting design loads cycle data that is driving the finite element modelling to figure out the internal loads. This informs the basis for the final design in 2007-8,” Peace says.

To Boeing’s relief, tests have also revealed that the latest revision to the wing structure has sufficient inherent stiffness to counter any flutter tendencies that designers feared could be brought on by the heavier GEnx-2B67 engines. “We’ve saved around 1,200lb by being able to eliminate the weights we thought we might have to put out there,” says Peace, who adds that the new, thicker wing is also mounted to the body with a slightly altered angle of “twist” to ensure the aft-loaded wing maintains an efficient incidence angle at cruise conditions.

“We’ve gone from critical to super-critical airflow,” says Peace, who adds the wing design follows the 787 and 777F in transferring more lift inboard.

The latest wing rendition, chosen at the end of April after undergoing further tweaks to eke out better cruise performance, also increases fuel capacity while maintaining the planned efficiency im­provements of the larger aerofoil design.

Fuel consumption is expected to be around 2.6 litres/passenger per 100km (0.7USgal/passenger/55nm) for the -8 versus 3.06 litres for the -400, assuming a 100% load factor and a 5,550km mission range. Fuel capacity for both passenger and freight models has grown by 14,000 litres to 241,590 litres for the Intercontinental and 229,100 litres for the -8F.

Wingspan increased

Although wingspan is increased to 68.4m and overall length for the -8F goes up to 76.3m, the span of the horizontal tail remains the same as the -400, which is good for both manufacturing, drag and weight. “The loads go up because of the larger moment arm, but we know how much to strengthen just a few parts as opposed to making the whole thing larger,” says Peace, who counters critics of the evolved design by saying “every time we go through a structural design you get better. You know what parts to make thicker and what parts to leave alone. On the 747 we’ve been through five of those – it’s a very efficient structure.”

The recent low-speed windtunnel tests are also a key part of Boeing’s continuing goal to meet QC1 (London Heathrow quota count) noise targets for arrival. “We are close to that, and a lot will depend on the testing over the next few months,” says Peace, who adds that the better up-and-away initial climb performance and chevron-equipped GEnx engines, plus simpler double-slotted inboard and single-slotted outboard flaps already reduce the take-off noise footprint area by 30% compared with the -400. The engines will be fitted with chevrons on both the primary and secondary nozzle exits, but Peace says Boeing has elected not to risk using “smart” adaptive chevrons on the primary exhaust duct.

“We are very confident on where we are with the projected noise without introducing that complexity,” he says.

Flight-control technology is being brought up to date with the introduction of fly-by-wire spoilers that enable them to be used for gust load relief, and therefore to help cut the structural strengthening required. The company is still looking at electrically signalled outboard ailerons as part of a current trade study.

“We will decide on that later this year as part of the firm configuration design,” Peace says.

Flightdeck decisions are all but complete, with the cockpit featuring a common 747 type rating blended with 777/787 functionality and operational commonality. Although today’s 747-400 crews will have no problems recognising the flightdeck, they will notice new elements such as a 787-style cursor control device, an electronic checklist and a high-speed datalink control on the glareshield. Also visible will be a new Honeywell flight-management computer large enough to handle the extra processing requirements of reduced vertical separation minima, and the vertical situation display on the multifunction displays. The aircraft will also be provisioned for electronic flight bags on the outboard side of the displays.

Market projections

As for market projections, Boeing believes there is a requirement for around 900 passenger and freighter aircraft of 747 size and larger over the next 20 years. “About 300 of these show up in the new larger freighter category, and we think we’re going to do very well in the freight market versus the A380,” says Peace. “Of the remaining 600, we think half will be in the 400- to 500-passenger range and half in the 500 or greater, and of that half is predicated on the belief that some routes will require that capacity later in the forecast period. Going forward we think we ought to be get about half out of the 900. We think we have a hell of a value proposition,” concludes Peace.

Source: Flight International