Aircraft fuel efficiency
 

Hi

Can someone please help me with the following.

I wish to calculate the fuel effeceincy for the aircraft below. I need to use the following parametres below.
A/C 747
FUEL BROUGHT FORWARD 5005 LITRES
FUEL BURN =1850 LITRES
PLANNED AIR TIME = 1.19
SPECIFIC GRAVITY = 0.80
ACTUAL ZERO WEIGHT = 212900

A 747 with a burn-off of only 1,480 kgs.

I'd say that was your typical burn at 390T getting to RNW 25R at LAX
after a gatehold, which is pretty efficient in my book as it usually took
2000+ kg without it.

You won't be able to go far on 4 odd tonnes of fuel though.

On about four tonnes of fuel, you might get one circuit in before it's all gone.

Maybe, but you'd have to be empty, be towed to the runway,
retain F20 after TO, fly a close-in circuit at 1,000ft and leave
the gear late in order to make it with all 4 Pratts or GEs still
working at the end of an idle-reverse landing roll.

One could shut down say No 3 on reaching 1,000ft to save
fuel in that situation, but I think it'd be 3/5ths of 5/8ths of
stuff-all considering the remaining distance to fly.

Since its the TO f/flow that buggers one up, I'd stay V2+10
straight to 1,000ft, starting the turn to downwind as early as
possible to get those GNMs/1,000 up and running.

Interesting thinking, but how about just taking off with no payload and very little fuel .... on only the inboard engines. Leave the flaps at 10° all the way around and just go to 20° for landing, leave the gear down, and that way the ADP's on #1 and #4 should cope.

Yep good one - F10 would be less drag than F20, but I dunno
about the total burn from brakes release to 1,000ft being less
for 2 eng/gear down vs 4 eng/gear up.

One of us will have to jump in a sim.

Fuel efficiency
 

Is there a specific way to do this calculation. I am a uni student and need to find this for a number of aircraft flying to the same destination.

Please can you help.

The problem is that your question doesn't make a lot of sense - You have given the fuel burn and the flight time, (one or the other impossible for the 747 unfortunately) so you can work out fuel Vs time yourself.

Fuel efficiency
 

Hi

Thanks for getting back. I may have noted the figures below. This is the data I have that I am suppose to use. I may have noted the a/c type wrong. I have the values below for a few different a/c types flying to the same location.

FBF 7400
FUL 14365
UT LITRES
SG 0.787
FOD 18000
FOA 10400
PBO 6901
BLF 6.25
TF 6.32
LNT 7.55
BLN 8.05
PAT 1.22
ZFW 107254

A/c effeciency
 

Hi

Thanks for getting back. I may have noted the figures below. This is the data I have that I am suppose to use. I may have noted the a/c type wrong. I have the values below for a few different a/c types flying to the same location.

FBF 7400
FUL 14365
UT LITRES
SG 0.787
FOD 18000
FOA 10400
PBO 6901
BLF 6.25
TF 6.32
LNT 7.55
BLN 8.05
PAT 1.22
ZFW 107254

:confused: