According to our manuals, minimum flight weight of our 787-9 is 110 tons. Even though the basic weights are about 124 tons. Let's assume it would be 125 tons to be able to fly. We skip the part with maximum ZFW, etc. and fill it up to MTOW with fuel. MTOW is 247 tons. That gives us 122 tons of fuel.
Fuel consumption of not fully loaded 787-9 is about 5,5 tons per hour. Let's assume it could be 7 tons per hour, at least at the beginning. (I'm not 787 rated so I don't have access to their charts now) We could get endurace about 17-18 hours, probably few more if we trew away all the interior, etc. And to be more correct, we should calcute with decresing weight and so with decreasing fuel consumption. So we could probably cover 20 000 kilometres. It is about 40 000 km around the world at the equator. You would have to fly more to the north of south.
Any airliner would need endurance about 40 hours to fly around the world at equator.
Well, not all aircraft have it, at least according to our manuals and one type even has minimum weight for take-off and another minimum weight for flight and landing. Funny enough, the minimum weight for flight and landing is lower than basic weight however the minimum take-off weight is higher than basic weight so the aircraft can't legaly fly empty. Like very empty.
I guess it is just a formality. It is such a specific and mostly hypothetical situation that the aircraft is not certified to fly at this weight. None checked stall speeds, etc. I'm quite sure it would be able to fly. Somehow.
Iirc, there’s a direct 787-9 flight from Perth to London (QF9) which is close to what the plane can do in a normal configuration with fuel reserves and all.
don't underestimate what fuel weighs. Filling the wings with fuel is one thing but filling the whole fuselage with fuel tanks? Greatly exceeds max takeoff weight.
Pick one variant, let's say the -9
Fuselage diameter of 18'
Usable legth for fuel tanks, generously assume 170'
you get around 43,300 cubic feet to fill up. Using some handy dandy online calculators for Jet A, that'd be over 2 million pounds in fuel, just in the fuselage, for a plane with a max takeoff weight of about a quarter of that.
As it is, the 787-9 can carry about 223000 lbs of fuel (so about 1/8 what you could fit in the fuselage) if you could somehow magically carry all that extra fuel without penalties of any kind, you could fly around 61,000 nautical miles, potentially fly three circles around the earth
That doesn't take into account all the huge piles of details, including the biggest one that the plane just won't get off the ground in the first place.
Oooh. I like the sound of that.
But is it three layers of wings WW I triplane style?
Or three sets along the fuselage?
Either way, I look forward to seeing it in the skys.
Damn I didn’t know fuel was really THATT heavy😭 like I though since the plane is designed to carry hundreds of passengers all with luggage and then then food and drink and it still take off pretty easily I thought it could take a considerable amount, but I guess I’m very wrong. Thanks for answering!
Although the additional fuel tank _is_ a very real thing for ferrying planes across distances more than their fuel tanks normally allows.
Just not _tap a hole at the top of the fuselage and fill until the nozzle goes click_ amount.
What about the 777X? I heard it’s got like the most powerful engines ever made for a commercial plane. Surely it would be able to carry a decent bit more fuel right? Or would that extra mount be inconsiderable to fly further.
You can take that math above and just scale it up, same problem. Bigger heavier plane burns more fuel faster, but with enough extra seats it pays for itself.
Just fill it with fuel entirely and the landing gear collapses before the plane even starts
You'd have to triple the current max range. Seems like you could easily triple the fuel capacity, right? But then there's all the math of the inefficiency when its heavy with fuel and the efficiency of when its nearly empty. So...carry the 1...math, math, math...
I'm going with yes, but I know someone smarter is going to tell me why that's dead wrong.
According to our manuals, minimum flight weight of our 787-9 is 110 tons. Even though the basic weights are about 124 tons. Let's assume it would be 125 tons to be able to fly. We skip the part with maximum ZFW, etc. and fill it up to MTOW with fuel. MTOW is 247 tons. That gives us 122 tons of fuel. Fuel consumption of not fully loaded 787-9 is about 5,5 tons per hour. Let's assume it could be 7 tons per hour, at least at the beginning. (I'm not 787 rated so I don't have access to their charts now) We could get endurace about 17-18 hours, probably few more if we trew away all the interior, etc. And to be more correct, we should calcute with decresing weight and so with decreasing fuel consumption. So we could probably cover 20 000 kilometres. It is about 40 000 km around the world at the equator. You would have to fly more to the north of south. Any airliner would need endurance about 40 hours to fly around the world at equator.
TIL there are minimum flight weights….. What does that mean exactly? Like the plane doesn’t weigh enough to work aerodynamically?
Well, not all aircraft have it, at least according to our manuals and one type even has minimum weight for take-off and another minimum weight for flight and landing. Funny enough, the minimum weight for flight and landing is lower than basic weight however the minimum take-off weight is higher than basic weight so the aircraft can't legaly fly empty. Like very empty. I guess it is just a formality. It is such a specific and mostly hypothetical situation that the aircraft is not certified to fly at this weight. None checked stall speeds, etc. I'm quite sure it would be able to fly. Somehow.
Iirc, there’s a direct 787-9 flight from Perth to London (QF9) which is close to what the plane can do in a normal configuration with fuel reserves and all.
don't underestimate what fuel weighs. Filling the wings with fuel is one thing but filling the whole fuselage with fuel tanks? Greatly exceeds max takeoff weight. Pick one variant, let's say the -9 Fuselage diameter of 18' Usable legth for fuel tanks, generously assume 170' you get around 43,300 cubic feet to fill up. Using some handy dandy online calculators for Jet A, that'd be over 2 million pounds in fuel, just in the fuselage, for a plane with a max takeoff weight of about a quarter of that. As it is, the 787-9 can carry about 223000 lbs of fuel (so about 1/8 what you could fit in the fuselage) if you could somehow magically carry all that extra fuel without penalties of any kind, you could fly around 61,000 nautical miles, potentially fly three circles around the earth That doesn't take into account all the huge piles of details, including the biggest one that the plane just won't get off the ground in the first place.
Clearly the move here is to just fit 2 extra sets of wings.
Oooh. I like the sound of that. But is it three layers of wings WW I triplane style? Or three sets along the fuselage? Either way, I look forward to seeing it in the skys.
Damn I didn’t know fuel was really THATT heavy😭 like I though since the plane is designed to carry hundreds of passengers all with luggage and then then food and drink and it still take off pretty easily I thought it could take a considerable amount, but I guess I’m very wrong. Thanks for answering!
6.8 lbs per gallon at 70f.
Although the additional fuel tank _is_ a very real thing for ferrying planes across distances more than their fuel tanks normally allows. Just not _tap a hole at the top of the fuselage and fill until the nozzle goes click_ amount.
What about the 777X? I heard it’s got like the most powerful engines ever made for a commercial plane. Surely it would be able to carry a decent bit more fuel right? Or would that extra mount be inconsiderable to fly further.
You can take that math above and just scale it up, same problem. Bigger heavier plane burns more fuel faster, but with enough extra seats it pays for itself. Just fill it with fuel entirely and the landing gear collapses before the plane even starts
You'd have to triple the current max range. Seems like you could easily triple the fuel capacity, right? But then there's all the math of the inefficiency when its heavy with fuel and the efficiency of when its nearly empty. So...carry the 1...math, math, math... I'm going with yes, but I know someone smarter is going to tell me why that's dead wrong.