When going on an ultra-long haul flight, with a flight time of over 12 hours, flying on the Boeing 787 or Airbus A350 aircraft is almost certain. With ground-breaking technologies and sophisticated operations, these two aircrafts are the best of what the two rivalling companies offer to airlines competing for the best customer experience and range. However, in such a climate conscious world, fuel efficiency is something that is heavily discussed as people are trying to revert the world back to its unpolluted state. In this comparison, I will compare the Boeing 787-10 with the Airbus A350-1000 deeply analysing and explaining its fuel economy. Which do you think is the most efficient based on its sleek looks, the A350 or Boeing 787?
What determines the efficiency of an aircraft?
There are many factors mainly related to the construction of an aircraft which affect the efficiency of it, in simpler terms, it’s the rate at which an aircraft uses one gallon of fuel. Firstly, the aerodynamics of an aircraft is very important. An aircraft with hard edges, corners and an overall blocky shape is more likely to require more thrust to move forward, as it creates more drag/air resistance, than a more streamlined shape allowing the particles around it in the air to flow easily. Needing less energy to overcome the resistance, high efficiency is achieved as less thrust is required to accelerate the aircraft.
Second most importantly is the engine’s fuel consumption. Since the first jets to be used in the 1950s, modern aircraft’s engines produce approximately 80% less CO2 per passenger; however as new technologies rising, it needs to be made use of. A very common way of increasing efficiency of an engine is by altering its design and material. Using in-expensive light-weight materials decreases the mass, so during takeoff, the plane won’t need to gain a high speed (again, something that requires thrust and fuel) and can instead go airborne when slightly slower. This even includes building an aircraft from light and composite materials to avoid using too much fuel. Often when you are booking a flight, you may see there is a limit to how much your bags can weigh because the airline pays for the fuel, instead of making profit! In addition, modifying the internals components in attempt to reduce friction when the engine is working at its optimum minimises the amount of wasted energy through heat or sound. So what are engine manufacturers such as Rolls Royce and General Electric doing? Estimated to complete by 2025, General Electric, Rolls Royce and Safran Aircraft Engines are developing new technologies to see a potential return in propeller jets for large aircrafts by using light-weight materials and implementing better aerodynamic structures. These “open rotor” engines are said to allow aircrafts to travel at higher speeds and create lower levels of noise all whilst being 16% more efficient than current jet engines. Tests on prototypes of this idea show that these engines could provide a 25% to 30% increase in fuel efficiency.
In addition, the area and span of the wing contributes a lot to staying in flight. The wings of an aircraft help generate lift for the aircraft to take off, land and cruise. This essential force keeps the airplane in the air. The larger the area of the wing, more lift can be created. This is because lift is directionally proportional to the surface area of an object, in this case the wing. Therefore, with that information in mind, doubling the area also doubles the lift meaning it is easier for an aircraft to take off and land at a lower speed and using less fuel, similar to the material properties mentioned earlier. So a larger wing equals more lift. Gliders, an aircraft with no engine, have a massive wingspan (15 meters for a 2seater glider) which creates enough lift so that they can fly for up to 6 hours or even more without any thrust.
Plus, a key component used on all aircrafts including passenger jets and cargo aircrafts, flaps at the back of the wing play a massive role when performing take offs and landings. During these vital parts of flight, flaps can be configured in several angles that face down to redirect the flow of particles so that the airplane gets pushed up keeping it airborne. For example, in 2008, a catastrophic aircraft accident occurred with a British Airways Boeing 777 aircraft where it crash landed just before the runway at Heathrow Airport. With a dual engine failure, at 240 feet the pilots retracted the flaps from 30 degrees to 25 degrees which allowed the airplane to glide further without any thrust. This one move saved the lives of nearly everyone onboard. This shows that an aircraft with flaps can glide for longer when landing or taking off. Flaps play a crucial role as they allow the aircraft to fly with less thrust wasting less fuel.
Similarly, whilst talking about the wing, wingtips (more commonly known as winglets) reduce the wingtip vortex, a circular pattern of rotating air particles left behind when lift is generated. Aircrafts with normal wings which are flat at the end often create more drag than modern planes with wingtips. When drag increases, more thrust is required to overcome it which also needs fuel.
All these small features of modern airliners are the reason why aviations global CO2 emissions are 2%. These features indirectly affect the efficiency of an aircraft allowing long flights to occur such as the new London to Sydney route operated by Qantas with their Airbus A350.
The comparison you have been waiting for!
To start off with, the Airbus A350-1000 has a range of 8,700 nautical miles (10,003 miles) whereas the Boeing 787-10 has a range of 7,000 nautical miles (8,055 miles). You can see that the A350 has a head start in this category. Also, assuming both aircrafts are in a standard 3-class configuration, the A350 can carry 46 more passengers than the B787. The A350 at max capacity could fit 369 and the B787 can fit 323 passengers. Although the A350 can travel far with more passengers, it also requires much more fuel than a 787.
Moving on, the Airbus A350 has a total thrust of 864 kN (194,200lb) which is greater than the 676 kN (152,000lb) of total thrust of the B787. You may be bewildered by looking at these big numbers, I’ll explain them. Total thrust is the maximum force generated by the engines to move forward; so although the A350 will take you on holiday slightly faster (if travelling at max speed) it will consume fuel at a much faster rate than the B787. Plus, the Rolls-Royce Trent XWB engines used on the Airbus is more than a thousand kilograms heavier than compared to the Boeing 787’s Rolls-Royce Trent 1000 engines, weighed in at 6100kg compared to 7400kg. Less weight needed to carry means less thrust is needed which justifies the reason the Boeing’s engine create less thrust. So, when in service they are very similar but on paper and according to calculations the 787’s engines are more efficient as they require less thrust to lift any given weight. Also, the 787’s engines are smaller and made of lighter materials than those used on the A350’s Trent XWB engine.
Both aircraft’s fuselage is quite similar, like any other modern airliner, their shape is streamlined and aerodynamically fine so no real comparison can be done. The A350 is slightly longer measuring 73.78 meters than 68.27 meters on the 787, but this is mainly to carry more passengers. Not to forget, the 787 is made out of composite materials such as carbon laminate and carbon sandwich which are both extremely light weight materials. Similarly, the A350’s fuselage is made out of “carbon-fibre reinforced polymer”. Although this isn’t related, I love the look of the cockpit windows on the Airbus A350’s fuselage! Aren’t they cool? I think they are!
Furthermore, attached to both their fuselages, are the wings. The Boeing 787’s wingspan is 60.17 meters making it shorter than the 64.75 meters of wing on the A350 (note this is the measurement of just one wing not both combined, they really are massive). The Airbus also has a larger wing area measuring at 443 meters squared, more than the 787’s 347 meters squared wing area. This means, as I mentioned earlier, the A350 can create more lift, but the large wing size compensates for the long body of the aircraft. The 787 having a smaller wing does not mean it’s worse; the smaller wing is the size it is because of airport restrictions and cost because for the smaller body, a larger wing is unneeded.
Finally, to reduce drag and wingtip vortex, the A350 has a stylish winglet which has been praised by many aviation enthusiasts and engineers by its purpose and also its looks. Although the B787 has no wingtips, when in flight, the curvature of the aircraft’s wing makes up for it.
Conclusion
Overall, bearing in mind all these facts, the Boeing 787-10 is preferred more by aviation enthusiasts and passengers. This is mainly because of the comfort the passengers receive and the stunning features available to them. However, the main question is which is kinder to our fragile and precious environment? As the Airbus A350 variant is newer, in my opinion, I believe that it is less damaging to our world. From the revolutionary winglets to the new touch screen displays available to the pilots, it’s not only safer but also less harmful to the Earth. Although many do prefer the A350 efficiency wise, the 787 is a great aircraft. Why else have airlines chosen to operate the 787, with orders totalling up to 1,455? I must say that both these aircrafts are awesome and having travelled on both, it is a shock to see how far aircrafts and the efficiencies have come.
