The fuel burn complexity of the 777-X has many components under consideration for those who seek out its value. If it reaches out and touches the world beyond 8,000 (sm), it will carry more dead weight in fuel at take-off to make the journey. Every aircraft made has the same problem. An exponential conundrum of fuel weight added for route mile required. The heavier the aircraft flies the more fuel weight it must store on-board in its flight travels.
Another formulation of this suggest an operations puzzle, and is as old as flight itself, even with the birds. The source of energy, fuel, is a penalty to flight duration. A fat bird needs its storage to fly further but will burn more because of the fat. Kind of like a dog chasing its tail to get somewhere in the house.
Another component is fuel price per gallon for each seven lbs of fuel. Now add additional weight penalties such as 400 passengers, crew, luggage and supplies. Pretty soon an operator is about about to sink its ship. Many a sailing ship back 300 years ago went to the bottom with too much gold during rough times. This analogy is appropriate to flying. Weight is the bane of airlines today as fuel prices spike, and can sink an airlines financials in just one month of operations. Advanced sales of tickets three months prior to departure could bankrupt a company unless they have sufficient safety margins installed on that ship.
The 777-X hopes to install those built in margins by building a feather that will haul a lot of passengers and fuel so it can fly farther on less fuel. Back to the conundrum, load more weight with fuel, so an airline can burn more fuel to carry its more fuel. Go dog go and chase that tail, and get your passengers to the other side of the world. Fuel weighs about 7+ lbs a gallon no matter what, and contains so much fat energy like the long flight Albatross birds. So where does the 777-X break this evil hold on long distance flight, since it has not come up with a light weight fuel alternative? The Albatross glides for miles and does not constantly beats its wing to save on energy. The new X air frames for Boeing seek that glide with its less thirsty engines. The three W's, Weight, Wings and a Whisper. Noise sounds just like drag should sound. Booming its ugly voice in flight while those engines are hard at work. Think how a little tiny humming bird sounds like with its non-aerodynamic structure. It buzzes like a bee with a large body in proportion of its wing size and doesn't whisper.
Boeing tries to build a super lightweight feather of an aircraft in its 777-X and load on the Jet-A and passengers. Below are the weight constants that remain unmovable:
- Passengers who pay for its own weight.
- Fuel that moves the weight from A to B
- Luggage because its luggage.
- Crew and supplies
The simple part is now factored in, while the price of fuel is running loose destroying financial dreams. Boeing proposes to move in the direction of deploying energy efficient Jet Engines that will require less gallons to fly the same distances of today's conventional aircraft. That is how they will make "lighter fuel" is through extremely efficient engines. Lighter passengers are found through interior advancements in its seats, overhead bins, and cargo areas. The lighter aircraft, can come from CRFP wings, wing box, and core architectures. Using advanced aluminum skin, lite fasteners and weight saving components gained from the 787 project. Weight loss won't come from those bullet point constants, but will come from the structure and efficiencies that supports those weight constants. Boeing's bridge to success is losing weight through indirect means by having a better aircraft that will fly farther on less gallons and weight. Paying attention to Boeing's 777-X MTOW is the key to how they will compete. Once the MTOW is locked in and design efficiencies are established, then analysis can be made on the affects towards more distance with less fuel weight can be made. Flying a heavy, is expensive to all airlines, Boeing wants to fly a heavy substantially lighter and fill the gaps with a more efficient equipment. That is the X Goal. I close with this thought, "The 747 will not kill the giant A-380, that remains for Jack The Giant Killer, the 777-X."
WSJ referring article: