Hi,A320FirstOfficer (Martin) and myself thought it would be interesting to fly a couple of routes using different aircraft of similar mass.The first two aircraft that came to mind were the MD-11 vs. 747, to fly the following routes:* SHORT RANGE: Heathrow to Zurich (EGLL to LSZH)* MEDIUM RANGE: Copenhagen to Dubai (EKCH to OMDB)* LONG RANGE: Heathrow to Anchorage (EGLL to PANC)The aircraft must be loaded with approximately 90000 lbs of payload, plus an accurate fuel loading for the flight. The routing and fuel load will be left up to you, but the aim is to use as little fuel as possible whilst complying with minimum fuel requirements (APU + taxi + trip fuel + 5% nav contingency + divert + 30 mins holding + extra + minimum fuel for type).747-400 Minimum Fuel: 5500 kg (12100 lbs).MD-11 Minimum Fuel: 5000 kg (11000 lbs).When you've flown, post your routing, traffic load, fuel taken for the flight (before start) and fuel after landing (after shutdown) and flight time.To eliminate weather as much as possible, you must use the FS "Cold Fronts" weather theme.Good luck!Best regards,Robin.

To eliminate weather, shouldn't you use the Clear weather theme?

The theme provides the same weather for everyone. I should add that "rate of change" should be NONE.Best regards,Robin.

I'm intrested in knowing what you are studying.

I'm intrested in knowing what you are studying.

We thought it would be fun to see who can make these flights using as little fuel as possible, based on the parameters provided. :) We are going to fly these routes as well!Will also be interesting to see 747 vs. MD-11 performance/fuel consumption.Best regards,Robin.

We thought it would be fun to see who can make these flights using as little fuel as possible, based on the parameters provided. :) We are going to fly these routes as well!Will also be interesting to see 747 vs. MD-11 performance/fuel consumption.Best regards,Robin.

Well i can tell you allready that the 744 uses more then the MD-11 does the 744 uses under normal cruize conditions 10.000 kg's per hour and it's a simple math 3 versus 4 engines it's more logic that 4 engines uses more then 3

Well i can tell you allready that the 744 uses more then the MD-11 does the 744 uses under normal cruize conditions 10.000 kg's per hour and it's a simple math 3 versus 4 engines it's more logic that 4 engines uses more then 3

Sorry, it is simple logic but it is wrong. 4 uses more then 3 if, and only if, they are identical engines under identical conditions and identical load.

Which is more or less the case with the CF6-80C2 and PW4000 engines used on both aircraft.

Sorry, it is simple logic but it is wrong. 4 uses more then 3 if, and only if, they are identical engines under identical conditions and identical load.

Which is more or less the case with the CF6-80C2 and PW4000 engines used on both aircraft.

So we are talking about the engine's individual? i think there is more into count like wing design,aerodynamics i'll be on some research i will come back later for the result

Which is more or less the case with the CF6-80C2 and PW4000 engines used on both aircraft.

More or less? More less then more, I think.

More or less? More less then more, I think.

The MD11 and 744 don't use the exact same engine sub-type and they are not operating under exactly the same conditions, but I think they are comparable enough to warrant Johans statement. Similar cruise speed, similar cruise altitudes and similar thrust ratings. Under those conditions four engines burn more fuel than three engines. It's not like he was comparing a GE90 to a Rotax engine. What you said about fuel consumption is true, but it doesn't matter much in this MD11 vs. 747 fuel flow comparison as both types use similar engines.

If Johans logic was valid, why don't all 747 operators switch two engines off as soon as they reach cruise?

If Johans logic was valid, why don't all 747 operators switch two engines off as soon as they reach cruise?

Possibly for the same reasons that MD11 operators don't switch off the No 2 engine once they reach cruise.

The reason for not shutting down an engine in flight is because the loss of thrust and relative increase in drag of the shutdown engine requires a greater increase in thrust (and thus increased fuel flow on the remaining engines) than the engine would have produced had it been running. Nice idea, but sadly it doesn't work.Why don't you try the routes and post your results?Best regards,Robin.

Robin,What about gate numbers for each flight?