aircraft fuel consumption question


#1

does anyone know how many gallons per hour major aircraft burn? what does a DC-9 burn compared to say an A320 or 737… A CRJ compared to an ERJ. Anyone know infor like that or where to find it?


#2

Enter the terms aircraft fuel burn rate into Google.


#3

I already did that. I found great consumption rates for military aircraft but nothing in line for passenger a/c


#4

Did you look up individual aircraft or manufacturers. Try boeing.com and airbus.com and the other manufactuers’ sites.


#5

Just as a heads up, it’s usually in pounds per hour.


#6

From http://www.boeing.com/commercial/747family/technical.html

747-400
Capacity:…57,285 gallons
Range:…7,260 nm / 8,349 Statute miles
Cruise speed:…567 mph

Doing a little math with the numbers given:
Range (statute miles) divided by Speed = 14.7 hours
Capacity divided by hours = 3,897 gallons per hour
6 pounds per gallon times 3,897 = 23,382 pounds per hour

===========================

777-200
Capacity:…31,000 gallons
Range:…5,210 nm / 5,991 Statute miles
Cruise speed:…567 mph
Range (statute miles) divided by Speed = 10.6 hours
Capacity divided by hours = 2,924 gallons per hour
6 pounds per gallon times 2,924 = 17,544 pounds per hour

===========================

737-800
Capacity:…6,875 gallons
Range:…3,383 Statute miles
Cruise speed:…530 mph

Range (statute miles) divided by Speed = 6.4 hours
Capacity divided by hours = 1,074 gallons per hour
6 pounds per gallon times 1,074 = 6,444 pounds per hour


#7

Now I have a question along these lines…
Flying the 737-400 (in MS Flight Simulator), the engine stack on the instrument panel has “FF/FU” which I assume has something to do with fuel flow. It ranges from about 0.7 at idle to 11.5 at full-throttle.

What is this unit of measure? 11.5 what per what? 11,500 lbs/hr?

I typically cruise at about 3.9 to 4.1. A few mor points and I will overspeed. So if my calculations above are correct, then this really doesn’t make sense as I would be cruising at 4,100 lbs/hr, but my calculation for the -800 is 6,444 lbs/hr.

…or is THIS as real as it gets? :laughing:


#8

When you try to calculate mathematically from the total fuel and the range, you’re assuming that fuel burns are linear. I don’t fly big aircraft, but the bizjet I fly carries just over 19,000 pounds of fuel (6.7 pounds per gal, not 6)

A recent trip was flown at low altitude because of strong headwinds west bound. It took 3.2 hours and we burned 11,100 pounds or 1657 gallons.

That works out to 3469 pound (518 gallons) per hour.

The return trip - same mileage was flown at normal altitudes. It took 3 hours and we burned 7270 pounds or 1085 gallons.

This is 2423 pounds or 362 gallons per hour. Big difference.

Another consideration is ATC … sometimes you can’t get as high as you’d like, particularly over the North Atlantic.

A final thought…generally speaking you burn 10% of what you carry, so if you take 1,000 extra gallons of fuel you will burn 100 gallons to carry it.


#9

If I can assume your screenshot is at full throttle near sea level, the back of my napkin (20,000 lbf thrust per engine and 0.5 /hr TSFC) says yes, it’s thousands of pounds per hour.


#10

Hopefully you know already that not much in MSFS is very accurate, especially the stock aircraft.


#11

[quote=“NeedleNose”]
Now I have a question along these lines…
Flying the 737-400 (in MS Flight Simulator), the engine stack on the instrument panel has “FF/FU” which I assume has something to do with fuel flow. It ranges from about 0.7 at idle to 11.5 at full-throttle.

What is this unit of measure? 11.5 what per what? 11,500 lbs/hr?

I typically cruise at about 3.9 to 4.1. A few mor points and I will overspeed. So if my calculations above are correct, then this really doesn’t make sense as I would be cruising at 4,100 lbs/hr, but my calculation for the -800 is 6,444 lbs/hr.

…or is THIS as real as it gets? :laughing:
quote]

FF would be fuel flow in pounds per hour
My guess is that FU is fuel used and there is a some way to bring up that data.

In a Spey powered Gulfstream (G2, 2B, G3) the fuel flow at sea level at Min EPR (the Gulfstream way of saying max power) is in excess of 9000 lbs/hr/engine. At cruise altitude it is back at 1600-1800 lbs/hr/engine. While what you are seeing in the flight sim may not be exactly accurate it is not out of the realm of the realistic.[/quote]


#12

Yeah, I knew there’s more to it than that, but I took the information I had available and ran with it hoping to arrive at some sort of ball park figures.

Guess that 0.6 pounds per gallon mistake adds up quickly when hauling thousands of gallons! :blush: Read that one on the Internet and used it. Could be the difference between getting off the runway and aborting (or over-running it). Maybe a little weight and balance issue when loading the cargo…

http://i16.photobucket.com/albums/b8/CheckM8/loaded.jpg

Yep. It was taken during a full-power takeoff roll at IAD (Elev. 313’).

I take it for what it’s worth. I realize that they use the same panels for different types and models, but didn’t realize fuel flow would be so significantly different. Are my calculations above that far off? …or is Flight Simulator that far off?


#13

The flight dynamics are usually out of whack, even for some of the good free add-on models. I’m a stickler for that kind of thing, since I play mainly for the flight dynamic portion of it rather than the plain enjoyment of flying different airlines. One thing that X-Plane excels at.