747-400, is it really that inefficient?

[captainklm 1]

Wins what?

being the money maker

[captainklm 1]

I think we had the conversation about facts and guesses before. Using your figures: 747 => 20,000lbs/h to move 400 people = 50lbs per hour per person, 777 => 16,500lbs/h to move 300 people = 55lbs per hour per person. So by your figures, the 747 is 5 lbs of fuel per hour per person more efficient then the 777. Do you agree or do you want to make up some more figures?

does anyone here have exact figures?

[Valcor 9]

Or, you could learn common sense and critical logic and we would all benefit. Even your last sentence is silly, "777f vs 747-400F then the -400 wins by a mile". What does that mean? In what way is one 'better' then the other? You have spent (wasted) half this thread saying teh 747 was inefficient and now you say it will win "by a mile"? Please...

If you could learn some common decency to other members of the forum, we would all benefit. You've had an awful nasty attitude to captainklm this whole thread. He's just relating something he found interesting that he heard on the news. God forbid he does not quote directly from a Harvard/Yale/MIT joint study on aircraft efficiency. And as someone else pointed out, comparing the fuel cost per seat is about 1/10th of the tricky equation of figuring out aircraft costs.

[dmwalker 607]

captainklm,I expect the airlines have exact figures. I don't know how forthcoming they are on these topics but you could try asking JAL since their own website states about the Boeing 777-300ER that “This environmentally friendly aircraft is 20% more fuel efficient than the 747-400, and produces less noise and exhaust.”. I would imagine that this was one of the reasons why JAL sold off their entire fleet of 747s. Also, Wikipedia's entry for the 777 has a reference which states that “Several airlines have acquired the -300ER as a 747-400 replacement amid rising fuel prices.”Dugald Walker

[Paul_Smith 92]

If you could learn some common decency to other members of the forum, we would all benefit. You've had an awful nasty attitude to captainklm this whole thread. He's just relating something he found interesting that he heard on the news. God forbid he does not quote directly from a Harvard/Yale/MIT joint study on aircraft efficiency. And as someone else pointed out, comparing the fuel cost per seat is about 1/10th of the tricky equation of figuring out aircraft costs.

I am sorry that you have got so upset, but if you read the opening sentence of the quote which (I presume) triggered your ire, you would notice that I said "I think we had the conversation about facts and guesses before" and while I would not expect you to be current with the contents of every thread on Avsim, I would have thought it not unreasonable for you to assume from that sentence that the issue of presenting stuff as statements of fact has been raised with CaptainKLM before. From the rest of the post, you might have gathered that this was not the first time CaptainKLM has taken gossip, hearsay, or just plain made up stuff and presented it as gospel, and when questioned on it, was unable to provide any creditable reference as a source for these so-called facts. The whole basis of this thread, as I am sure you already know, was the assertion that the 747 was less efficient then the 777 but the only figures that CaptainKLM offered to support this, showed the the 747 was MORE efficient. I have no idea where CaptainKLM got the figures he presented, perhaps it was a joint Harvard/Yale/MIT study, or perhaps it was the cartoon channel. Either way, they say nothing about the efficieny of either aircraft and a lot about they way CaptainKLM approaches knowledge and information.Now, does that satisfy your sense of decency, or would you prefer to duel at dawn?

[Valcor 9]

I am sorry that you have got so upset, but if you read the opening sentence of the quote which (I presume) triggered your ire, you would notice that I said "I think we had the conversation about facts and guesses before" and while I would not expect you to be current with the contents of every thread on Avsim, I would have thought it not unreasonable for you to assume from that sentence that the issue of presenting stuff as statements of fact has been raised with CaptainKLM before. From the rest of the post, you might have gathered that this was not the first time CaptainKLM has taken gossip, hearsay, or just plain made up stuff and presented it as gospel, and when questioned on it, was unable to provide any creditable reference as a source for these so-called facts. The whole basis of this thread, as I am sure you already know, was the assertion that the 747 was less efficient then the 777 but the only figures that CaptainKLM offered to support this, showed the the 747 was MORE efficient. I have no idea where CaptainKLM got the figures he presented, perhaps it was a joint Harvard/Yale/MIT study, or perhaps it was the cartoon channel. Either way, they say nothing about the efficieny of either aircraft and a lot about they way CaptainKLM approaches knowledge and information.Now, does that satisfy your sense of decency, or would you prefer to duel at dawn?

1) If you feel you've participated in a similar conversation, feel free to skip this one.2) He readily explained it was in Japanese but even so, directly linked a youtube link to provide his source. 3) Who cares if he presents stuff that could be considered gossip or heresay? Have you visited the Microsoft Flight forum lately?4) I though duels were done at high noon? I can't be bothered to get up at dawn :)

[lovetofly28 0]

I think we had the conversation about facts and guesses before. Using your figures: 747 => 20,000lbs/h to move 400 people = 50lbs per hour per person, 777 => 16,500lbs/h to move 300 people = 55lbs per hour per person.So by your figures, the 747 is 5 lbs of fuel per hour per person more efficient then the 777. Do you agree or do you want to make up some more figures?

Your wrong, you figured that it would be 20,000lbs per hour; however, that depends on winds, cargo, route, CI, thrust on TO and landing, etc... The T7 is more efficient because of Thrust to Weight Ratio. The ratio for the 744 on AVERAGE is .27, and for the T7 is .304, so the T7 is more efficient. This can be proven by using the formula RATIO=THRUST/WEIGHT; thus, B747-.27 and T7-.304, so there you have it, proven mathematically. Now who's making stuff up?

[yos233 1]

I have an easy settlement for this. Everyone look at this topic, and fly the routes. We can compete by flying different different aircraft and comparing a mean value. Enter your data here.

[captainklm 1]

Your wrong, you figured that it would be 20,000lbs per hour; however, that depends on winds, cargo, route, CI, thrust on TO and landing, etc... The T7 is more efficient because of Thrust to Weight Ratio. The ratio for the 744 on AVERAGE is .27, and for the T7 is .304, so the T7 is more efficient. This can be proven by using the formula RATIO=THRUST/WEIGHT; thus, B747-.27 and T7-.304, so there you have it, proven mathematically. Now who's making stuff up?That sounds good, how muchmore can it be? Please keep in mind that I said it's at full weight with no winds

I have an easy settlement for this. Everyone look at this topic, and fly the routes. We can compete by flying different different aircraft and comparing a mean value. Enter your data here.

That's a good idea, but where are we going to get a realistic 777-300ER?So anyway is the 747-400 able to compete today? Is there a plane of the same size that is more expensive to operate?

[Paul_Smith 92]

Your wrong, you figured that it would be 20,000lbs per hour; however, that depends on winds, cargo, route, CI, thrust on TO and landing, etc...

I know I am wrong. I prooved I was wrong. Of course, I had the advantage of having actually read what was going on.

On Japanese tv they where saying JAL said it was bad and everything. But I read on a net JAL told that to the media. You never know, it could be an excuse. I believe ANA said the same to. Do you want me to post the link, there all in JapaneseOk,A 744 burns on average 20,000 pounds of fuel an hour. No winds or any other factorsA 77w Burns about 16,500 pounds of fuel an hour. Thats about 20%, operating costs and how much money is made should also be considered

To which I replied:

I think we had the conversation about facts and guesses before. Using your figures: 747 => 20,000lbs/h to move 400 people = 50lbs per hour per person, 777 => 16,500lbs/h to move 300 people = 55lbs per hour per person. So by your figures, the 747 is 5 lbs of fuel per hour per person more efficient then the 777. Do you agree or do you want to make up some more figures?

...The T7 is more efficient because of Thrust to Weight Ratio. The ratio for the 744 on AVERAGE is .27, and for the T7 is .304, so the T7 is more efficient. This can be proven by using the formula RATIO=THRUST/WEIGHT; thus, B747-.27 and T7-.304, so there you have it, proven mathematically. Now who's making stuff up?

If you would like to talk about making stuff up, perhaps you would be kind enough to tell us why you think thrust to weight ratios would matter to anyone other then a rocket scientist, or what it has to do with efficiency? CaptainKLM might be young and a bit quick at jumping to conclusions and a bit slow at identifying his sources, but at least he seems to grasp efficiency is subtle and complex subject that requires more then just a simple ratio.

[scandinavian13 5,192]

Your wrong, you figured that it would be 20,000lbs per hour; however, that depends on winds, cargo, route, CI, thrust on TO and landing, etc... The T7 is more efficient because of Thrust to Weight Ratio. The ratio for the 744 on AVERAGE is .27, and for the T7 is .304, so the T7 is more efficient. This can be proven by using the formula RATIO=THRUST/WEIGHT; thus, B747-.27 and T7-.304, so there you have it, proven mathematically. Now who's making stuff up?

While you're not making stuff up, you're neglecting a hugely important factor: how much fuel it takes to make that thrust. Your T/W ratio statistics are similar to those made by car manufacturers now of "500 Miles Per Tank!"Congratulations, I could have a 500 gallon tank and get 1MPG. Efficiency? Hardly.The F-22 has an enormous T/W ratio, but the fuel required to generate that thrust is nowhere near efficient when compared to passenger aircraft.Airlines don't have perfectly exact numbers, which is how business runs. My Germans are better than your Germans (stolen quote from one of my favorite movies - anyone know it?), my equations predict the lottery, and my planes somehow outperform your planes using this complicated math stuff. Nobody has perfection or all of the knowledge, which is partially where the variations in business lie. The world doesn't operate in a vacuum, but we're close enough to come up with approximations. Those approximations will cost you money, however, if I have them and you don't.For what it's worth, a firm across the pond from me that releases its data to those deemed worthy (applications based on necessity/merit - yes, I'm being intentionally vague), listing values at several flight levels and weights shows the following:B744, mid-weight, FL350: approx 550 lb/min burnB772, mid-weight, FL350: approx 450 lb/min burnNow, what is left to be defined is how those lb/min can be argued to be more or less efficient. How many passengers are carried at mid-weight? How much are those passengers willing to pay for those seats? How much did they actually pay? How much in fees do we pay for each aircraft? How much in maintenance?Discuss.

[captainklm 1]

While you're not making stuff up, you're neglecting a hugely important factor: how much fuel it takes to make that thrust. Your T/W ratio statistics are similar to those made by car manufacturers now of "500 Miles Per Tank!"Congratulations, I could have a 500 gallon tank and get 1MPG. Efficiency? Hardly.The F-22 has an enormous T/W ratio, but the fuel required to generate that thrust is nowhere near efficient when compared to passenger aircraft.Airlines don't have perfectly exact numbers, which is how business runs. My Germans are better than your Germans (stolen quote from one of my favorite movies - anyone know it?), my equations predict the lottery, and my planes somehow outperform your planes using this complicated math stuff. Nobody has perfection or all of the knowledge, which is partially where the variations in business lie. The world doesn't operate in a vacuum, but we're close enough to come up with approximations. Those approximations will cost you money, however, if I have them and you don't.For what it's worth, a firm across the pond from me that releases its data to those deemed worthy (applications based on necessity/merit - yes, I'm being intentionally vague), listing values at several flight levels and weights shows the following:B744, mid-weight, FL350: approx 550 lb/min burnB772, mid-weight, FL350: approx 450 lb/min burnNow, what is left to be defined is how those lb/min can be argued to be more or less efficient. How many passengers are carried at mid-weight? How much are those passengers willing to pay for those seats? How much did they actually pay? How much in fees do we pay for each aircraft? How much in maintenance?Discuss.

Thanks,you made things clear. So sometimes possibly on rare occasions the 744 can be more efficient to the T7. Say if its the same company on the same route with same pricing etc, the T7 has head wind the whole time while the 744 has tail wind the whole time can the 744 be more efficient? Like make more money and stuff?Also the movie quote is it The right stuff...

[Paul_Smith 92]

Thanks,you made things clear. So sometimes possibly on rare occasions the 744 can be more efficient to the T7. Say if its the same company on the same route with same pricing etc, the T7 has head wind the whole time while the 744 has tail wind the whole time can the 744 be more efficient? Like make more money and stuff?Also the movie quote is it The right stuff...

Is it? I thought it was from Dr. Strangelove but you may be right. Anyway, you are half way to efficiency, but not quite there yet. It is not the headwind/tail wind that makes the real difference since that would only affect a single flight. One measure of efficieny (but not the only one) is profitablity. If, on a given route, I can expect an average of X passengers per flight over a year, then the most "efficient" plane for that route is the one that lets me move those passengers for the lowest cost. So how much does it cost to move each passenger? We know it costs money to have a plane for a year even if it never leaves the ground. Every time it takes off or lands costs money. Every hour it flies costs maintenence and crew money and every pound it carries costs fuel money. So as you can see, workng out how much it actually costs to carry a single passenger one mile is already a difficult equation that depends on how many passengers you carry and how many miles you carry them. What makes it even more complex is how many you are expected to carry. A 777 might have the lowest cost per passenger mile but only if it is nearly full on every flight and in the air 21 hours a day. If you only expect 80 passengers on a 300 mile route, and only fly twice a day, you might be better off with a 737-200, and an MD80 might be the cheaper option if you want 110 passengers on a 450 mile route. Instead of asking which is the more efficient, perhaps it would be more useful to ask which is the more appropriate, when you take everything else into account?

[Matt2218 4]

Anyway, you are half way to efficiency, but not quite there yet. It is not the headwind/tail wind that makes the real difference since that would only affect a single flight. One measure of efficieny (but not the only one) is profitablity. If, on a given route, I can expect an average of X passengers per flight over a year, then the most "efficient" plane for that route is the one that lets me move those passengers for the lowest cost. So how much does it cost to move each passenger? We know it costs money to have a plane for a year even if it never leaves the ground. Every time it takes off or lands costs money. Every hour it flies costs maintenence and crew money and every pound it carries costs fuel money. So as you can see, workng out how much it actually costs to carry a single passenger one mile is already a difficult equation that depends on how many passengers you carry and how many miles you carry them. What makes it even more complex is how many you are expected to carry. A 777 might have the lowest cost per passenger mile but only if it is nearly full on every flight and in the air 21 hours a day. If you only expect 80 passengers on a 300 mile route, and only fly twice a day, you might be better off with a 737-200, and an MD80 might be the cheaper option if you want 110 passengers on a 450 mile route. Instead of asking which is the more efficient, perhaps it would be more useful to ask which is the more appropriate, when you take everything else into account?

Agree 100%. Likewise, the purchase or lease price for a new 77W will be astronomical compared to a used 744...which means the utilization rate had better be very high for the 77W's fuel savings (compared to a 744) to matter. Even then it takes years.This is why older aircraft can be successful as freighters even after they are no longer competitive on passenger routes - getting them cheaper makes up for burning more fuel because they don't fly nearly as many hours per day/year.Airliner economics are pretty complicated...

[lovetofly28 0]

While you're not making stuff up, you're neglecting a hugely important factor: how much fuel it takes to make that thrust. Your T/W ratio statistics are similar to those made by car manufacturers now of "500 Miles Per Tank!"Congratulations, I could have a 500 gallon tank and get 1MPG. Efficiency? Hardly.The F-22 has an enormous T/W ratio, but the fuel required to generate that thrust is nowhere near efficient when compared to passenger aircraft.Airlines don't have perfectly exact numbers, which is how business runs. My Germans are better than your Germans (stolen quote from one of my favorite movies - anyone know it?), my equations predict the lottery, and my planes somehow outperform your planes using this complicated math stuff. Nobody has perfection or all of the knowledge, which is partially where the variations in business lie. The world doesn't operate in a vacuum, but we're close enough to come up with approximations. Those approximations will cost you money, however, if I have them and you don't.For what it's worth, a firm across the pond from me that releases its data to those deemed worthy (applications based on necessity/merit - yes, I'm being intentionally vague), listing values at several flight levels and weights shows the following:B744, mid-weight, FL350: approx 550 lb/min burnB772, mid-weight, FL350: approx 450 lb/min burnNow, what is left to be defined is how those lb/min can be argued to be more or less efficient. How many passengers are carried at mid-weight? How much are those passengers willing to pay for those seats? How much did they actually pay? How much in fees do we pay for each aircraft? How much in maintenance?Discuss.

What was the point of that post, to disprove me? NASA states that thrust to weight ratio's can be used to calculate efficiency, so, the 777 is more efficient, assuming both have the same proportional weight, same route, same wind, same cost index, same proportional passengers, same proportional everything, the 777 is .034 more efficient. Maybe I'm wrong, but if I am your going to have to prove it by replying with something that shows me otherwise.