Fuel consumption for different aircrafts...

[qunow]

In a previous thread I have mentioned about some disparity on fuel consumption number for data in airwaysim compare to data on other webpages of certain aircraft model although I was not able to dig out referencable source for that... And recently I have read a post on the airliners forum which listed out the fuel consumption for different airplanes http://www.airliners.net/forum/viewtopic.php?f=5&t=1355819 which seems to have quite a few points that are notably different from data in airwaysim although the original post does not specify source nor detailed comparision criteria...
some more notable things are: il-62/707/DC8/il-96/Tu-114 consume ~9000 kg/h fuel in the game while it's ~5000-6000 in the post
345 consume 8000 in the post while it's ~6500 in the game
DC7/Lockheed constellation consume ~1000-1500 kg/h fuel but they're ~2000-3000 in the game iirc
Can someone who have access to relevant data source check and verify which of those numbers are more correct...?

[schro]

The problem with that guy's post (that I observed when I first read it whenever he posted it) is that he presents absolutely zero verifiable references for his claims. He makes it sound like he's making a few assumptions and perhaps licking his finger and sticking it in the air to determine the wind direction's impact on his numbers. Thus, that being said, I would not trust any of his data until he presents how he arrived at each figure (i.e. which sources of data he used and the assumptions he made about the flight length and such).

The other difficult thing in the game is that fuel burn is FAR more complex than is presented to the end user. The game has data about the flight profile of each aircraft (take off burn, time to altitude, cruise burn, descent burn, etc) which is not presented to the end user. What's presented is the average number that we see, and that average is computed by assuming a stage length for a given aircraft flight and presenting the calculated value for that (unknown) stage length. 

In the case of the DC7 and Lockheed planes, they're classified as large planes in the game, but are often used on long haul routes where the fuel burn profile will be quite different. However, since their "average" is presented with the flight profile of a "large" airplane, it's going to show that it's higher than with that of an average "very large" airplane.

Ninja edit - In general, the game's data sources come from flight manuals from the respective aircraft and/or real world data.

[gazzz0x2z]

I made a lot of experimentation for A148 vs CRJ700, and yes, in game, fuel consuption profile are very complex. You drink only slightly much with the A148 up to 1000NM, at 1500NM you're already 15% above the CRJ in terms of fuel costs, and beyond 1800NM(the A148E domain), it's just not worth flying the A148 when fuel has a real cost.

So yes, the information given is misleading. And my experiments did sometimes give different results because of winds(I guess, I'm not sure, but it would explain quite a few things). So numbers shown are not enough to have a good idea. It would be so cool to know that the A148 will drink 8,2 tons(or whatever) flying from Glasgow to Saint-John with 60 pax, while the CRJ700 will drink only 7,4 tons in a similar situation. And see that from Glasgow to Belfast, the difference is negligible. Currently, we don't. We just have raw numbers, and per hours, therefore highly misleading, as slower airplanes seem better than they really are.

[qunow]

I understand that data posted by original post are not exactly reliable and thus I was asking for if there are any more reliable source.
And I also notice how different type of weather and flight pattern would drastically affect aircraft's fuel consumption, at least there are takeoff + cruising + landing in the game, but still when averaged out i dont think it would result in something like 50-100% difference unless in ultra short or ultra long sectors.
And would it be better if the game is to say fuel consumption in kg/km instead of kg/h? And consequently give out the number for fuel consumption at cruising instead of average fuel consumption in a typical mission?

[schro]

The problem is, you're comparing game data (which you do not know the exact formula for how it was computed) and you're comparing it to some random guy on the internet's posting (for which you do not know the source of, nor do you know how he computed it).

Game data is sourced from generally reliable sources such as the actual flight manuals for aircraft and I believe there are some Jeppesen publications/products that will contain the data.

[Alexmain]

If you think that the creators of the game used the manuals for calculating fuel consumption this is a big delusion. There is no need to compare the fuel consumption in game with the real one, these are different things. Just take it as a reality for yourself, it's still only a game. For example, the real L-1649 Starliner had a fuel capacity of 9600 US gal or about 24,000 kg of fuel. If it burned 2000-3000 kg / hour, then it could fly only 8-12 hours or about 3700-5500 km, so it could not even cross the Atlantic . Although TWA made a non-stop flight from London to San Francisco at a distance of 8600 km with 40 passengers on board in 23 hours 19 minutes. I doubt that they managed to take on board 42,000 kg of fuel even if there was an extra tank in the cabin , while MTOW is 72600 kg and OEW is 42900 kg. So 1250 kg/h  for L-1649 seem quite realistic while another Constellations burned even less because they are lighter and smaller.

9000 kg/h for DC-8 ? Yes DC-8 with JTA4  burned around 7000 kg/h , but  here is a page from the DC-8 operating manual with JT3D
At the bottom of the table, there are corrections for different landing weights. The data in the table is given for 180000lbs.


Here is a page from the soviet Tu-114 operating manual
left side is weight in tonns , Vист - real speed in km/h, Q- fuel burn in tonn per hour. As you can see at the cruising speed of 770 km / h it burned 6400-5200 kg / h.
So what was the real fuel consumption of Tu-114 and DC-8-63?  9000 kg/h?

Here is an order of the Ministry of Civil Aviation of the USSR on fuel consumption rates for its aircraft. At the bottom there are tables where the number of hours  of flight on the left and the minutes upstairs are indicated. The amount of fuel in the tables in kilograms http://lawru.info/dok/1974/11/15/n1187967.htm Those who developed these norms have never played games but were well acquainted with the statistics. Now you know the fuel consumption of DC-8-63 and some Soviet aircraft. What is more like the truth? Data from the game or from your link? Game is not a real life.

[NovemberCharlie]

If you think that the creators of the game used the manuals for calculating fuel consumption this is a big delusion. There is no need to compare the fuel consumption in game with the real one, these are different things. Just take it as a reality for yourself, it's still only a game. For example, the real L-1649 Starliner had a fuel capacity of 9600 US gal or about 24,000 kg of fuel. If it burned 2000-3000 kg / hour, then it could fly only 8-12 hours or about 3700-5500 km, so it could not even cross the Atlantic . Although TWA made a non-stop flight from London to San Francisco at a distance of 8600 km with 40 passengers on board in 23 hours 19 minutes. I doubt that they managed to take on board 42,000 kg of fuel even if there was an extra tank in the cabin , while MTOW is 72600 kg and OEW is 42900 kg. So 1250 kg/h  for L-1649 seem quite realistic while another Constellations burned even less because they are lighter and smaller.

I suggest you report these with a bug report. Sami will adjust based on proper sources. If no proper sources are available (e.g. prototypes, rare aircraft, etc.) estimations must be made.
In game the A330-200 uses more fuel than the -300. This seemed odd to me and when I presented credible manuals, Sami adjusted it (too late for the current GW3 though :p)

This game is as good as it's (active) community!

[Alexmain]

I suggest you report these with a bug report. Sami will adjust based on proper sources. If no proper sources are available (e.g. prototypes, rare aircraft, etc.) estimations must be made.
In game the A330-200 uses more fuel than the -300. This seemed odd to me and when I presented credible manuals, Sami adjusted it (too late for the current GW3 though :p)

This game is as good as it's (active) community!

A330-200 burns an average of 100 US gal less than -300 according to US Department of Transportation statistics  for Delta airlines. I will give figures from statistics for United in 2016, you can compare them with the game
738 - 836 gal/h
737-720 gal/h
772 - 2218 gal/h
788 - 1581 gal/h
789 - 1769 gal/h
763 -1603 gal/h
764 - 1664 gal/h
744 - 3496 gal/h
A320 - 797 gal/h
A319-737 gal/h

Delta 2016

A332 - 1987 gal/h
A333 - 2084 gal/h
763 - 1696 gal/h
764 - 1868 gal/h
772 - 2486 gal/h

United 2015

763 - 1560 gal/h
764 - 1732 gal/h
788 - 1554 gal/h
789 - 1737 gal/h
772 - 2207 gal/h
744 - 3467 gal/h

AA 2016

772 - 2358 gal/h
773 - 2749 gal/h
788 - 1719 gal/h
763 - 1567 gal/h

Here is all US Department of Transportation statistics https://www.transtats.bts.gov/DL_SelectFields.asp?Table_ID=297

[Alexmain]

I understand that data posted by original post are not exactly reliable and thus I was asking for if there are any more reliable source.
And I also notice how different type of weather and flight pattern would drastically affect aircraft's fuel consumption, at least there are takeoff + cruising + landing in the game, but still when averaged out i dont think it would result in something like 50-100% difference unless in ultra short or ultra long sectors.
And would it be better if the game is to say fuel consumption in kg/km instead of kg/h? And consequently give out the number for fuel consumption at cruising instead of average fuel consumption in a typical mission?

If you want to know how much fuel you need to fly a particular airplane in the specific conditions, then only the real operating manual will help you, where  will be tables for fuel consumption for climbing, cruise flight, descent in different conditions. The average figures are given to understand the difference in AVERAGE consumption for different aircraft for its usual range , not to make a real flight plan for any conditions. It should be understood that if the E190 burns 1850 kg/h at 700nm then for 787 on this route the consumption will not be 4800 kg / h , it will be no more than 4300 kg / h because aircraft will be very light. But 787 is mainly operated on long routes, so the average flow is greater. But when quad engine A345 in the game burns 6500 kg/h and in reality twin 773 according to the statistics burns 7800-7900 kg/h, then clearly there is some mistake and obviously not in the statistics of the real airlines.

[NovemberCharlie]

Yeah I know it burns less and it has been changed for future games, using the operation manual I provided. I am suggesting that you, with the manuals you showed earlier create a bug report, so the developers have a chance to update their figures. If you have a credible source they will fix it.

[NovemberCharlie]

But when quad engine A345 in the game burns 6500 kg/h and in reality twin 773 according to the statistics burns 7800-7900 kg/h, then clearly there is some mistake and obviously not in the statistics of the real airlines.

Actually I believe that may not be too far off. I fly 777 and we often use a rough calculation of 7000kg/hr. And a while back a A340 captain, who was going to the 777 mentioned that the fuel flow for the A343 was very similair to the 777-200ER. The popularity of the 777 comes down to payload/range capability and cargo. And for the -300ER the amount of cargo+passengers.

[Sami]

I find it a bit strange that you Alexmain make such comments with such a commitment when you have never even used the sim - I do not see that you have ever logged to a single game world with your account..... 

Also one should also understand what was talked earlier here: The quoted "kg/h" value is not just "flight time * fuel" type of thing but the total fuel consumption calculation is much more sophisticated in AirwaySim based on a complete flight profile. (there are seven different data points for each phase of the flight, and the weight factor is also included)

And indeed, all forum posts as reliable sources can be ignored. Only reliable data comes from AFM/FCOM, but for most of the times such data is not available (very old planes for example). But if there are clear errors then the bug reports forum is the correct place to post the data since that is the only way it will be tracked/checked and potentially fixed for sure.

Given the vast amount of aircraft models included there are errors for sure, even though the base data used is very reliable.. But I know that especially the Russian models will need more data to make their model better.

[Alexmain]

I find it a bit strange that you Alexmain make such comments with such a commitment when you have never even used the sim - I do not see that you have ever logged to a single game world with your account..... 

Also one should also understand what was talked earlier here: The quoted "kg/h" value is not just "flight time * fuel" type of thing but the total fuel consumption calculation is much more sophisticated in AirwaySim based on a complete flight profile. (there are seven different data points for each phase of the flight, and the weight factor is also included)

And indeed, all forum posts as reliable sources can be ignored. Only reliable data comes from AFM/FCOM, but for most of the times such data is not available (very old planes for example). But if there are clear errors then the bug reports forum is the correct place to post the data since that is the only way it will be tracked/checked and potentially fixed for sure.

Given the vast amount of aircraft models included there are errors for sure, even though the base data used is very reliable.. But I know that especially the Russian models will need more data to make their model better.

For Soviet aircraft, you can safely use these data http://lawru.info/dok/1974/11/15/n1187967.htm , it's certainly not manuals where there are corrections for the wind, the load and etc, but these norms are developed based on the operation of real airplanes so they can be completely trusted. It is necessary to remember the real cruising speed of the aircraft. For example, the IL-62 is a fairly slow aircraft with a cruising speed of 820 km / h, so it consumes much more fuel at high speeds.  I hardly imagine reliable sources that were used for the game according to which the turboprop Tu-114 burns as much fuel as the wide-body IL-96. As far as I understand the data from nowhere are reliable sources, other than the manuals are not reliable. I admit that bristol brabazon burned 2000-2500 kg / h, but for DC-7  this is already too reliable sources.

Here is page from L-749 manual. Typical cruise power for 749 was 1200hp per engine

[Alexmain]

Here are the resources where you can find manuals for almost all Soviet aircraft including the latest SSJ100
https://www.avsim.su/files.phtml?search=%D1%80%D0%BB%D1%8D&sopt_mode=or&in_folder=16&sopt_title=1&sopt_desc=1&sopt_author=1&sopt_fname=1&sopt_comms=1&minrating=
http://aviadocs.com/RLE/
http://civilavia.info/?page_id=476

[qunow]

I find it a bit strange that you Alexmain make such comments with such a commitment when you have never even used the sim - I do not see that you have ever logged to a single game world with your account..... 

Also one should also understand what was talked earlier here: The quoted "kg/h" value is not just "flight time * fuel" type of thing but the total fuel consumption calculation is much more sophisticated in AirwaySim based on a complete flight profile. (there are seven different data points for each phase of the flight, and the weight factor is also included)

And indeed, all forum posts as reliable sources can be ignored. Only reliable data comes from AFM/FCOM, but for most of the times such data is not available (very old planes for example). But if there are clear errors then the bug reports forum is the correct place to post the data since that is the only way it will be tracked/checked and potentially fixed for sure.

Given the vast amount of aircraft models included there are errors for sure, even though the base data used is very reliable.. But I know that especially the Russian models will need more data to make their model better.

Can you share, for example, for a plane with capacity of around 250 people and a range of about 5000nm with cruise speed 0.80 mach, what would be the typical mission being used to calculate the fuel performance for the aircraft in the game?

[qunow]

see https://www.airwaysim.com/forum/index.php?topic=71718