Are the B787 Dreamliner’s claims to be a new generation in aircraft fuel efficiency over-stated?
Kevin Lister has written an open letter to the Aviation Minister, Theresa Villiers, pointing out to her that, despite all the hype about the Dreamliner being touted as the first of a new generation of planes, it is not greatly more fuel efficient than others. It is not likely to “solve” the industry’s future fuel or emission problems. Looking at the likely number of passengers, the range and the fuel capacity, the fuel consumption figures for the A380, Boeing 787, 777, and 747 very comparable. And are in the same range as the old Lockheed Constellation aircraft of the 1950s. The Dreamliner has lighter components, using carbon fibre rather than aluminium. But its main aim is to be a slightly smaller plane, that can fly long distance, without needing to refuel. This means carrying a great deal of fuel on take off for such a long trip. A doubling in a plane’s speed increases drag by a factor of four, and the power consumption of the engines by a factor of eight. Therefore, for greatest fuel efficiency, a plane would fly more slowly and over relatively short distances.
Open Letter to Theresa Villiers MP, Aviation Minister
Subject: Is the B787 Dreamliner the end of the road for aviation?
[Additional material from AirportWatch in square brackets].
[Boeing claim the Dreamliner is 20% more fuel efficient. It is interesting that Boeing very rarely say what they are comparing the Dreamliner against. The last comparison available when the 20% fuel saving was being used was against the Boeing 767. This is the most comparable plane to the 787. It is about the same size, it is wide bodied and used for medium haul flights, i.e. London to New York. It is also a design that is now is 20 years old. So the idea that the 787 provides a 20% improvement over the most modern jets on long haul, which is where its primary market is, does not stand to any worthwhile scrutiny.]
[It is also important to note that when ever Boeing or Airlines are talk about the 20% improvements, they very rarely specify what measurements they are using.]
[The Dreamliner has been given maximum hype as a “next generation” of aircraft, and the media has given this good publicity. But this appears to be little more than marketing hype and desperate marketing hype at that, given the news of cuts in orders. link The development costs of this plane have by far exceeded anything else. For example, the Boeing 747 development cost was $1 billion, and the 787 is $10 billion. However, the improvement in utility is decreasing from one generation of plane to the next. Eventually the industry will reach a point were developments costs exceed utility delivered and development of further planes becomes impossible. It is possible this point is being approached with the Dreamliner.
The Lockheed Constellation was the first plane to make intercontental air travel viable. This was a huge leap in utility over the previous mode of travel which was by ship and its development costs were extremely modest by modern standards, perphaps a couple of million dollars. Then the B707 came along and allowed more people to travel in jet style comfort. Again a big leap in utility, but not so big as the Lockheed. Its development cost rose to about $150million dollars and at the time nearly bankrupted Boeing. Then came the 747, which improved the jet travel experience and brought economies of scale. Still a big leap in utility, but a smaller leap than the introduction of the B707. Now we have the 787, which allows airlines to fly from regional airport to regional airport. The level of utility improvement is almost in category of “so what”, but the development costs to achieve this have been astronomical.
In terms of utility, there is a huge difference between the increased benefit society obtained at the beginning of the jet age with the introduction of new services that could link continents together (clearly this was before anyone thought about climate change) compared with the targeted benefit of the 787 which would allow someone to fly to San Francisco from, say, Bristol rather Heathrow. Furthermore every incremental improvement in utility requires an exponential increase in the development costs, which is likely to be financially unsustainable.
The supposed utility of the Dreamliner 787 is that the plane is meant to be lighter, although it came into service 8% heavier than its design weight. link
The aviation industry claims that flying high and fast is the most efficient. This compounds actual fuel efficiency, with saving time, staff wages, and more trips by the plane per day. The airlines put a premium on speed and getting the passenger to their destination fast. In order to fly fast you have to fly high to do it most economically. The jet planes of today are optimised for flying at around mach 0.8 (600 mph). If they were to fly at this speed in the lower and thicker atmosphere then their fuel consumption would rise, due to air resistance.
But if a plane was designed to fly at around 10,000 feet at 250 mph, it would always be more economical. Such a plane would have high aspect straight wings, a tubo prop, and have a limited range so it did not have to carry fuel. It would be totally unsuited to flying distances like London to Thailand direct.
If the airlines really want to cut their emissions per passenger, they need to fill every seat on every plane, every trip. And it means cutting down on first class and business class. However, in the past the biggest earner for the airlines was business class and first class. As companies are cutting back for financial and environmental reasons, (yes some are concerned about the CO2 footprint) many have made cutting executive travel and their airline bills their first priority. The result is that many planes will now have to come into service primarily with an economy class layout, selling tickets at economy prices.
This suddenly shaves operating margins down and makes the market highly cost sensitive. Planes must operate at near full capacity, especially as fuel prices increase. This was recognised by Boeing when they proposed the 787. Part of the rational was that it would be more important to run planes at full capacity in the future and that a smaller plane is easier to fill than a bigger one, especially from secondary airports. Put simply if they are now selling the plane on the basis that its “utility” is the ability to operate at full capacity because of its smaller size, it is an admission of failure as they have spent $10 billion on development for a product that is serving a declining market.]
Boeing 787 Dreamliner
The Boeing 787-8 Dreamliner is a superefficient airplane with new passenger-pleasing features. It will bring the economics of large jet transports to the middle of the market, using 20 percent less fuel than any other airplane of its size.
210 to 250 passengers
7,650 to 8,200 nautical miles (14,200 to 15,200 kilometers)
226 inches (574 centimeters)
197 feet (60 meters)
186 feet (57 meters)
56 feet (17 meters)
Total Cargo Volume:
4,400 cubic feet
Maximum Takeoff Weight:
502,500 pounds (227,930 kilograms)
SIZING UP THE BOEING 787 DREAMLINER AND THE AIRBUS A380
As I was browsing the net, I found this wonderful graphic comparing the two most anticipated aircraft – the Boeing 787 Dreamliner and the Airbus A380. The two companies have different philosophies on what airlines and people will want in the next generation of aircraft. Will they want the Airbus idea of carrying up to 850 passengers? or the Boeing idea of a smaller more fuel-efficient aircraft? Let’s compare the Boeing 787 vs Airbus A380.
- Operating Weight – 277,000 kg (610,200 lb)
- MTOW – 540,000 kg (1,235,000 lb)
- No. of Engines – 4 turbofans
- Max Engine Thrust – 374 kN (84,000 lb)
- Cruising Speed – 902 km/h
- Max Speed – 945 km/h
- Range – 14,800 km
- Ceiling – 43,000 ft
- Max Fuel Capacity – 81,890 gal (310,000 L)
- Flightcrew – 2
- Seating (Typical) – 555
- Seating (Max) – 840
Boeing 787 Dreamliner
- Flightcrew – 2
- Seating – 290-330
- MTOW – 165,100 kg (364,000 lb)
- Cruise Speed – .89 Mach (587 mph, 510 knots, 945 km/h at 40,000 ft)
- Rangle – 4,650 – 5,650 km (2,500 – 3,050 nm)
- Max Fuel Capacity – 33, 528 US Gal (126,903 L)
- Service Ceiling – 43,000 ft
- Max Thrust – 236 kN (53,000 lbf)
The Dreamliner is also not vastly quieter than other planes either.
Boeing ‘Dreamliner’ offers only marginal noise benefit – its “quietness” is exaggerated
Date added: May 5, 2012
The Dreamliner 787 has been much hyped, for its theoretical reduction in fuel use and in noise. Boeing claims it is 60% quieter, a statement that needs to be understood in terms of how aircraft noise is measured. It does not mean 60% quieter, in the way a layperson would understand the statement. It means actually a reduction of perhaps 3 decibels, to anyone standing under the flight path – a difference that is barely noticeable, even to trained ears. These figures are also theoretical, along the lines of the car fuel consumption figures given by manufacturers, and very difficult to replicate in real life. If the planes are heavier, taking off with more fuel and luggage on board, or landing on full power, they are still very noisy. And if there are more flights overhead, that is actually what people are bothered by, rather than a 3dB difference. Click here to view full story…
ASA brands Boeing “untruthful” over claim the 787 Dreamliner will be 60% quieter
The Advertising Standards Authority (ASA) has upheld a complaint by a London resident over Boeing’s claims in a recent advertisement that the new 787 Dreamliner, which is due to go into service later this year, will be “60% quieter than ever before”. The ruling comes barely a week after British Airways announced that it had finalised an order for 24 Boeing 787 Dreamliners. (HACAN press release)