Simviation Forums

I Just took a flight from Orlando Intl to Frankfurt Germany which is a 8 hour flight. I was flying a Boeing 747-400 and I had to refuel before I reached my destination.

I have flown on Delta airlines in a Boeing 747-400 from Columbia SC {CAE} to Atlanta Intl then to Frankfurt Intl
and we never had to refuel.

So why is that when I am flying the same jet on the game and I have to refuel before I reach my Destination.

A way to conserve fuel is to not fly with the throttle full open.  Choose a slower cruising speed and you will be able to make it no problem.  Atleast that is the idea.

If you use the flight planner it will give you a idea of how much fuel is needed. But be aware this does not include taxi and runing of the apu while at the gate. I have also noticed that if one tank gets low it will tell you that you need to refuel press ctrl x to transfer fuel. Perhaps this is what is going on

I did that and the Navigation log told me that the flight fuel needed would be 39658 GAL. and the Boeing 747-400 Fuel capacity is 57170.66 GAL.

Also factors in the fuel scenario are things like holding patterns, the route taken, and weather.  If you're flying into a 500 knot headwind, for extreme example, you're going to need a bit more gas.

Were your tanks full when you pushed back?  And if so, how long was your taxi time?  

Cybersurf,

The fuel consumption for an aircraft is a pretty complex relationship of a bunch of factors.  That is why "god" created Flight Management Computers  ;).  

Things that can affect fuel burn getting from point A to point B include:

• type / configuration of aircraft
• weight of passengers, baggage, and fuel aboard
• time spent on the ground with the APU running
• time spent on the ground with the engines running
• taxi time and distance
• amount of take-off and climb out thrust used
• precision of timing of stuff like extending / retracting gear, flaps, slats, spoilers
• precision of climbout and descent to designated altitudes
• throttle settings upon reaching cruise altitude
• having pitch trim correct on cruise
• prevailing wind speed and direction (cross / head / tail)
• number of altitude changes enroute
• precipitation (affecting airflow across around airframe)
• flight level selected (higher is thinner air...less drag / friction)
• accuracy of following departure procedures
• accuracy of entering approach pattern
• any holding time or go arounds

There is probably a few I am forgetting to mention.  Combining all of these factors determines how much fuel you will consume.

If it were easy....... everybody would do it  ;).

best,

...............john

Like what codered said, it's best not to have the throttle open all the way open throughout the flight. Taking off tends to eat up most of your fuel so after I level out I usually turn the #1 and #4 engines off (only on the really long flights ). You do lose some airspeed but if the weather conditions are good you won't lose to much...

God and shutting down engines isn't the answer.

The 747 should be able to complete the flight w/o refueling.

The real deal is precise climb speeds to an initial altitude of around FL 300; then climb to around FL400 with burn down of fuel.  A weight issue.  Don't know if it is represented in the sim.

Speed is also critical.  Check sim cruise data.  Likely .84M - .86M cruise.  Best fuel specs are a slowing with burn down with optimum altitude for max range.

Great circle route using GPS to minimize distance?  Jet stream also important and varies as to season.  With strong following jet, reduce M but not below optimum IAS for weight.

If you use the flight planner it will give you a idea of how much fuel is needed. But be aware this does not include taxi and runing of the apu while at the gate. I have also noticed that if one tank gets low it will tell you that you need to refuel press ctrl x to transfer fuel. Perhaps this is what is going on

Everyone keeps saying "APU" what is the "APU"

[quote]Also factors in the fuel scenario are things like holding patterns, the route taken, and weather.

Everyone keeps saying "APU" what is the "APU"

Auxiliary Power Unit.
It's a small jet engine, often located on the rear of the fuselage. It provides air condition, electricity (AC), bleed air for engines during start-up etc. The Boeing 747 of course has one

It's a very essential piece of hardware, and often makes a loud hissing sound when the aircraft is parked at the gate. Then, when the engines are up and  running, the APU is shutdown and you select one of the engine generators as the AC source

[quote]

Auxiliary Power Unit.
It's a small jet engine, often located on the rear of the fuselage. It provides air condition, electricity (AC), bleed air for engines during start-up etc. The Boeing 747 of course has one

It's a very essential piece of hardware, and often makes a loud hissing sound when the aircraft is parked at the gate. Then, when the engines are up and

It's definetely NOT the APU, since it's not modelled in the stock aircrafts, and also it's smaller than the other engines and won't use THAT much of fuel either.

Donnu what's the deal here.... =/

A check at FL300, M.84 747:
Fuel gauge check shows consumption as 24,000 lbs per hour.
Engine FF shows consumption as 21,600 lbs per hour.
Garmin shows 514 GS and 7.47 hrs of flight remaining.
Fuel consumption should be 179,280 lbs at the higher Fuel gauge rate.
Available was 364,300 lbs.
Fuel specs should improve substantially at FL400.

A check at FL300, M.84 747:
Fuel gauge check shows consumption as 24,000 lbs per hour.
Engine FF shows consumption as 21,600 lbs per hour.
Garmin shows 514 GS and 7.47 hrs of flight remaining.
Fuel consumption should be 179,280 lbs at the higher Fuel gauge rate.
Available was 364,300 lbs.
Fuel specs should improve substantially at FL400.

I mostly fly low altitudes such as 10000 FT because the higher altitude flown makes more presure on the aircraft which causes the aircraft to fly slower at full throtle therfore sence the aircraft is still at full throtle but it flies at a slower airspeed because of the high altitude presure that means that the engines have to work harder.

So I do not understand how  flying at higher altitudes could save on fuel consumpion because The engines are working harder...........