Are the B787 Dreamliner’s claims to be a new generation in aircraft fuel efficiency over-stated?

Date added: 7 May, 2012

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?

7.5.2012
Dear Theresa,

 [Additional material from AirportWatch in square brackets].

Boeing’s B787 Dreamliner world tour has just finished its stop over in the UK. The media presented it as the next generation plane that would sweep aside the challenges of climate change with the latest new technology.  Nothing is further from the truth. The reality is that the B787 is a high risk and desperate last throw of the dice by an industry whose survival is inherently incompatible with the combined crises of climate change and peak oil.
As you wrestle with the concept of making aviation sustainable, it is important you fully understand how the limitations of aero-engineering drive the commercial risk exposure to unacceptable levels.
Publicly available information on the Boeing 787  link  show the typical number of seats is 280, the fuel capacity is 138,700 litres  link  and a range of 15,700 km. link    Crudely, this gives a fuel consumption of 0.0316 litres/passenger km.  [The 787-8 is designed to seat 234 passengers in a three-class setup, 240 in two-class domestic configuration, and 296 passengers in a high-density economy arrangement.  So most will not have as many as 280 passengers, and will therefore have higher fuel consumption per passenger kilometer].
Similar data for the long range Boeing 777 is 350 seats, link   a fuel capacity of 181,283 litres, and a range of 17,000 km giving a fuel consumption of 0.0304 litres/passenger km.
Using the same data for the A380 gives 0.032 litres/passenger km.  link  [Using figures of maximum 644  passengers with 2 classes, range of 15,400 kilometers, and fuel capacity of 320,000 litres].   [Airlines generally have fewer passengers: for instance, Singapore Airlines offers 471 seats and a standard configuration is 555 seats.  Not  644 seats].
Thus there is little if any measurable improvement between the B787 and previous generation planes such as the B777 and the A380 when taken on this basis.
 [For the analysis, the longest range version of the planes was used  and the most modern version.  By comparison, the  Boeing 747-300  has range 12.400 km with 496 passengers, with 2 classes,  has 199,158 litres fuel capacity , which gives a fuel consumption of  0.032 litres per passenger kilometer.  link .  The Boeing 747-400 can take 524 passengers (2 classes)  link   Range 13,450 km and fuel capacity  216,840 litres, which gives a  fuel consumption of 0.0308 litres per passenger kilometer.  So there is no great improvement from the Boeing  747 either].
The immediate question this raises is what has happened to the much-hyped efficiency improvements of the B787? The answer is simple. The B787 is smaller than the B777 and A380. As such, it loses economies of scale.  So the new technology simply allows a smaller plane to fly with the same seat efficiency of a larger one and with a more comfortable interior.

[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.]

[There should be performance graphs available from the operating manuals of the planes which indicate the fuel requirements for various loads and ranges. These would be an upturned parabolla. So a very short haul flight is inefficient because of the over head of take off and landing. A very long haul flight is inefficient because of the energy needed to carry the fuel. There will be an optimum level somewhere between these two extremes. These graphs would be the best source of material, but they are not publicly available.]
But this was the business strategy. Boeing wanted to get the efficiency and range of a larger plane on a smaller plane to exploit the potential of the point-to-point transport model. This would enable the aviation industry to circumvent the restrictions of the major hubs such as Heathrow and continue to grow through exploitation of regional airports.
This business model is hubris on a grand scale. It flies in the face of all the platitudes of the aviation industry about their newfound concern for the environment.  Flying thousands of B787s around the world in a point-to-point network is the most effective way to maximise carbon emissions and it ignores the economic realities of escalating fuel prices.  [Though the Dreamliner is lighter, due to using carbon fibre rather than aluminium, these reductions in weight are dwarfed by the weight of the additional fuel that needs to be carried on very long haul flights]. 
If the aviation industry were genuinely concerned about carbon emissions, it would have used the technology in the B787 to design slower planes.  By way of comparison, the Lockheed Constellation of the 1940’s  link   had an efficiency of 0.0334 litres/passenger km.
This is well within the margin for error for the Boeing 787. Its equivalent efficiency to today’s super modern planes was delivered by basic physics. This tells us that drag is proportional to the square of speed, power is proportional the cube of speed and if you want to fly further you have to use energy to carry the extra fuel.  So doubling the speed increases drag by a factor of four and the power consumption of the engines by a factor of eight, making an efficient plane one that flies slowly over short distances.
So the claims of Boeing and the aviation industry to have produced a revolutionary fuel-efficient plane are wrong. Their technology simply allows smaller planes to continue to fly fast and cover the long distances that only larger planes could previously manage.
More critically the development costs of the B787 are an industry record of $10billion. [$32 billion ?  link  ] This gives the B787 the dubious distinction of having the lowest ever ratio between improvements over its predecessors to developments costs. It is another first associated with this plane, but one that Boeing’s marketing department keeps quiet. As such, the B787 brings aviation’s unsustainable trend of increasing development costs and diminishing returns to a critical apex.
The recent history of the A340 puts this risk into perspective.  link  The A340 served long haul routes, but being larger than the 787 its fuel consumption of 0.031 litres/passenger km was comparable.  When oil prices rose in 2008 operators could not run it profitably as its breakeven load factor increased to 120%. This led to the plane being taken out of service and the A340 production line was shut down in 2010.
Similar developments are now being witnessed with other airlines. Qantas recently announced a delay to its A380 programme. This is largely driven by diminishing margins in the face of rising fuel costs and carbon taxes. The same economics will inevitably apply to other airlines and they will come to similar conclusions. Policy makers must realise that these events taken together are cause for serious alarm, especially as the A380 was billed as the world’s most efficient plane on its recent debut into commercial service.
The danger for Boeing is as the economics of the B787 are not significantly better than the A340 on a per seat basis the whole project is highly exposed to increases in fuel prices.  It will take only a modest increase in the price of oil to render the whole project non viable, and with it much of the aviation industry.
 [When work on it started, the cost of oil was not an issue. The Dreamliner entered service in the same way as every other plane, which is to offer something better than its predecessors.  That might be a better lift/drag ratio, a longer range,  better passenger comfort.  This follows the trend of technological improvement started when the Wright Brothers flew their first plane. However, never once since the Wright brothers flew their first plane have aviation emissions reduced as a consequence of technological improvement.]
If this sounds implausible, then it is worth remembering that the B787 concept was developed in 2004 to allow growth in aviation to continue. It was not designed to help the industry consolidate in the face of rising fuel costs and environmental danger. The idea of whole classes of modern planes such as the A340 becoming redundant overnight was not even on the horizon.
These are fundamental issues no aviation minister can ignore. They determine future policy. Aviation growth cannot continue in the face of rising fuel costs, rising development costs and rising production costs. As such, the role of the aviation minister must be to chart the decline of the aviation industry in a way that can be done with the minimal amount of pain for those that are in the industry and those that depend on it.  The alternative is to ignore the evidence and wait for the industry to collapse suddenly and painfully and to take everyone else with it.
Yours sincerely,
Kevin Lister Bsc (aero Eng), MBA

[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.]

“According to Boeing, the jet can fly 52% further, burning 20% less fuel and saving more than 30% on annual maintenance costs than existing aluminium machines.”  link

Boeing 787 Dreamliner

787 – 8

Brief Description:
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.

Seating: 
210 to 250 passengers

Range: 
7,650 to 8,200 nautical miles (14,200 to 15,200 kilometers)

Configuration: 
Twin aisle

Cross Section: 
226 inches (574 centimeters)

Wing Span: 
197 feet (60 meters)

Length: 
186 feet (57 meters)

Height: 
56 feet (17 meters)

Cruise Speed: 
Mach 0.85

Total Cargo Volume: 
4,400 cubic feet

Maximum Takeoff Weight: 
502,500 pounds (227,930 kilograms)

and
787 – 9
http://www.boeing.com/commercial/787family/787-9prod.html
The 787-8 Dreamliner will carry 210 – 250 passengers on routes of 7,650 to 8,200 nautical miles (14,200 to 15,200 kilometers), while the 787-9 Dreamliner will carry 250 – 290 passengers on routes of 8,000 to 8,500 nautical miles (14,800 to 15,750 kilometers).

SIZING UP THE BOEING 787 DREAMLINER AND THE AIRBUS A380

http://pilotjohn.com/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.

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…

 

and

 

ASA brands Boeing “untruthful” over claim the 787 Dreamliner will be 60% quieter

9.1.2008

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)

ASA brands Boeing “untruthful” over claim the 787 Dreamliner will be 60% quieter

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Posted: Monday, May 7th, 2012. Filed in Climate Change News, General News, Recent News.