weight reduction versus fuel saving formula?

[Dimbleby]

Not sure if I have titled this thread correctly, and not even sure if I am posing the question correctly, but here goes.

Take an aircraft - any aircraft, but I will use a 737.

A 737 weighs X kg. Given that weight X, - and if say 100kg was majically shaved off it, what would be the saving in fuel over say the expected lifespan of the aircraft (lets say 30 years but it dosent really matter). Is there a universal formula or rule of thumb?

Tech oriented civvy asked and all I could think of was comparing ff at weight x, versus ff at weight (x - 100kg), X timespan/hours flown.:8

[CaptainSandL]

Very approximately…

Trip Fuel Reduction = Weight reduction x Flight time in hrs x 3.5%
Daily Trip Fuel Reduction = 100kg x 10hrs x 3.5% = 35kg/day
Annual TFR = 35kg * 350days = 12,250kg

Given a 25 year lifespan = 306,250kg

[Dimbleby]

Captain.

Much appreciated and sounds good enough for Dimbleby to avoid overt embarrasment.

Thanks again!:)

[math]

Hi dear,
I was wondering if you could provide me the sources (studies, etc.) on this relation between weight mitigation and fuel savings.
Thank you in advance.
Best regards

[compressor stall]

http://www.iata.org/whatwedo/Documents/fuel/airbus_fuel_economy_material.pdf

Have a read and sort out the maths for your questions yourself :ok:

[math]

hi compressor stall, thank you very much for the document. It will be useful !