16 replies to this topic

[Harrison.]

Hey guys, 

I'm just curious on why the 747-8 fuel cost is lower than a 777-300ER on the same route....

The 747-8 is incredibly fuel efficient, but it definitely still burns more fuel than a 77W...

So how is it calculated? The screenshot doesn't seem right...

 Screen Shot 2016-06-26 at 5.14.58 PM.png   718.4KB   1 downloads

 

[berubium]

Looks like the more efficient 777-300ER option in game has a 57,200 Fuel Flow & a speed of 555, while the 747-8I has a 53,200 Fuel Flow & a speed of 570, so in the game, the 747-8I is without a doubt the more efficient aircraft.  Whether or not that is true to real life, I don't know.

 

It seems like all 4 engine planes in this game are more efficient than their 2 engine counterparts, which seems abnormal.  Just compare the A340-300 & the A330-300 or the DHC7 & Q300.

[Harrison.]

Looks like the more efficient 777-300ER option in game has a 57,200 Fuel Flow & a speed of 555, while the 747-8I has a 53,200 Fuel Flow & a speed of 570, so in the game, the 747-8I is without a doubt the more efficient aircraft.  Whether or not that is true to real life, I don't know.

 

It seems like all 4 engine planes in this game are more efficient than their 2 engine counterparts, which seems abnormal.  Just compare the A340-300 & the A330-300 or the DHC7 & Q300.

 

Exactly, that was my point. It's completely illogical that a four engine aircraft would be more efficient than a twin engine of a smaller aircraft... 

If that was true in real life, well I think the 747-8 sales would be faring much better than they are currently

[konj1]

Yeah, it's strange, also, BAe 146 / Avro Rj is much more economical than any regional jet of its size until CS100 (or maybe faster E195).

Although I read that their their 4 engines were pretty good and efficient, I really wonder if they were constanty 15% better than F-100 or 717, it seems too much, idk...

[mariowebbocious]

This is the reason why I am confident in using A340 rather than A330.

This might seem a flaw in AE, but ...

[Talamare]

This is the reason why I am confident in using A340 rather than A330.

This might seem a flaw in AE, but ...

 

A330-300 is significantly better than the A340-300

[berubium]

Perhaps the fuel flow data the game is getting is fuel flow per engine (or pair of engines).  Could that be?

[Talamare]

Perhaps the fuel flow data the game is getting is fuel flow per engine (or pair of engines).  Could that be?

The game isn't broken, at best he is arguing that real life planes use different amounts of fuel than what the game lists. Tho, he isn't really providing any information on whether his statement is true or not. He just assumes that it is without doing research. 

 

@OP If you did do research on the subject, then post your findings. Post real world information about how much fuel each plane/engine uses.

[Harrison.]

The game isn't broken, at best he is arguing that real life planes use different amounts of fuel than what the game lists. Tho, he isn't really providing any information on whether his statement is true or not. He just assumes that it is without doing research. 

 

@OP If you did do research on the subject, then post your findings. Post real world information about how much fuel each plane/engine uses.

 

Has been quoted on the internet as 8t/hour for B77W and 10-12t/hour for the 747-8 

 

But then, no official stats are released and these numbers are quite hush hush.. these are unofficial estimates

[mariowebbocious]

A330-300 is significantly better than the A340-300

 

In which category?

 

Airbus A330-200 lowest possible fuel flow: 42,660

Airbus A330-300 lowest possible fuel flow: 40,500

 

Airbus A340-200 lowest possible fuel flow: 39,936

Airbus A340-300 lowest possible fuel flow: 39,936

 

I thought we were talking about fuel flow in AE.

[Stevphfeniey]

Bear in mind that I'm about 90% certain that fuel flow in AE is listed per engine, so you've gotta multiply those A340 numbers by four. Same deal with the 77W and 748.

[mariowebbocious]

Bear in mind that I'm about 90% certain that fuel flow in AE is listed per engine, so you've gotta multiply those A340 numbers by four. Same deal with the 77W and 748.

 

Then how do you explain the picture on the first post of this topic?

To be honest, I don't know the answer why. Because every time I fly both A330 and A340 on the same route, the A330 costs more fuel.

So I am, up to this point, 90% certain that the fuel flow represent all engine available. 

I could be wrong. 

[Talamare]

In which category?
 
Airbus A330-200 lowest possible fuel flow: 42,660
Airbus A330-300 lowest possible fuel flow: 40,500
 
Airbus A340-200 lowest possible fuel flow: 39,936
Airbus A340-300 lowest possible fuel flow: 39,936
 
I thought we were talking about fuel flow in AE.

 
For the cost of 564 fuel flow, aka 1% in Fuel Flow difference
The A330 costs 27m less, and has 15mins less turn time
 
So yea, it has slightly worse FF... The rest of its features are better than the 340. (Well, except for Range...)

In which category?
 
Airbus A330-200 lowest possible fuel flow: 42,660
Airbus A330-300 lowest possible fuel flow: 40,500
 
Airbus A340-200 lowest possible fuel flow: 39,936
Airbus A340-300 lowest possible fuel flow: 39,936
 
I thought we were talking about fuel flow in AE.

 
For the cost of 564 fuel flow, aka 1% in Fuel Flow difference
The A330 costs 27m less, and has 15mins less turn time
 
So yea, it has slightly worse FF... The rest of its features are better than the 340. (Well, except for Range...)

Then how do you explain the picture on the first post of this topic?
To be honest, I don't know the answer why. Because every time I fly both A330 and A340 on the same route, the A330 costs more fuel.
So I am, up to this point, 90% certain that the fuel flow represent all engine available. 
I could be wrong.

Nah, I'm pretty sure it's the plane's FF as a whole. The per engine thing is just wrong.

[berubium]

Bear in mind that I'm about 90% certain that fuel flow in AE is listed per engine, so you've gotta multiply those A340 numbers by four. Same deal with the 77W and 748.

I checked this out awhile back using A330s & A340s on the same route.  It definitely isn't per engine in game; rather it is per flight.

 

I also doubt that an A340 would have double the fuel consumption of an A330 in real life.  Significantly higher yes, but I assume the engines on an A340 wouldn't have to be as powerful as those in an A330.  A340s have been removed from many airlines rosters in real life because of operational costs, but I did get to fly in one from Cincinnati to Paris & back in 2003.  

[LJ Aviation]

THIS GAME NEEDS TO BE CHANGED

[KINGXyro]

Let's just hope for a major overhaul of the game in AE 4.0 which probably will happen when humans are extincted.

 

By the way I compared the following airliners and their fuel flow. (I didn't put the fuel flow but I placed the more efficient one.)

 

A333 > LOSE

A343 > WIN

 

B744 > LOSE

B772 (LR) > WIN 

 

A333 > WIN

B744 > LOSE

 

A343 > WIN

B772 (LR) > LOSE

 

Airliner:

A333 = Airbus A330-300

A343 = Airbus A340-300

B744 = Boeing 747- 400

B772 (LR) = Boeing 777-200 LR

[atnt71eb]

All the fuel flows in this game are fundamentally wrong. 

 

The game's fuel flow model is based on (1) total takeoff thrust and (2) takeoff thrust specific fuel consumption (SFC).

 

This is totally wrong for multiple reasons:

 

-The model assumes, basically, that the engines are at max thrust throughout the whole flight. In reality this is far from true - cruise thrust is a fraction of takeoff thrust, on the order of 25%.

 

-The model uses takeoff SFC for the whole flight. The real important figure is cruise SFC, which is always higher due to several reasons, the biggest of which is thrust lapse due to forward speed (an engine kicking out exhaust at 600mph produces more thrust at break release than when the plane is travelling at 500mph)

 

-The model takes no account of the aerodynamic/structural considerations that would dictate how much cruise thrust, and thus how much fuel, is needed. In cruise, thrust=drag. Drag is determined primarily by weight, wingspan, and wetted area of the plane. 

 

...taking all these into consideration would be a bit complicated. However, the model could use an average fuel flow figure from publicly available data like Airport Compatibility Manuals provided by the manufacturers, and then adjust for mission range (+/- a few percent depending on whether flying very short or very long distances).

 

The bottom line of all these discrepancies is that planes in this game burn significantly more fuel than they do in the real world. The assumption of maximum thrust dominates over the assumption of lower takeoff SFC. 

 

One more thing - folks assume that quads burn more than twins. That's a decent assumption for the kinds of actual twins and quads that we have, but the quads that we have are all old (747/A340) or else relatively poor designs (A380). 

 

Folks have noticed, for example, that quads are more efficient in this game than you'd expect. That's because the model is based on takeoff thrust: a quad needs less takeoff thrust than a twin because the total amount of thrust is related to takeoff requirements when one engine dies. Obviously this impacts a twin more than a quad, so quads will have less total takeoff power than a similarly-sized twin (all else being equal). Thus quads can have smaller engines, which helps fuel efficiency in a lot of ways that should be obvious. The A340-300, for example, was pretty close to the 777-200ER in real life fuel burn, despite being an older design. The A340NG is just a bad idea - too much stretch of a narrow fuselage and therefore too heavy a plane.