How affects weight in fuel consumption. Any graphics?

[Fergonfi]

Una pregunta que necesito para un trabajo :
Que diferencia en consumo hay en un 320 entre ir sólo con la tripulación o con todas las plazas ocupadas.
Para un turboprop de 40 plazas la diferencia sería similar?


Anyone can help me with some graphics to understand the influence of weight in the fuel consumption.?
Any difference A320 and turboprops 40 seats capacity?

Thanks colleages.

[Tinstaafl]

Are you trying to quantify the effect of weight on fuel consumption for those types you listed? Or are you just trying to understand why it happens?

Can't help with graphs or charts to quantify the amount, but as for why (apologies if this isn't what you're after):

The aircraft has Weight (structure, fuel, payload). In straight & level flight this Weight must be supported by Lift ie Lift acts to oppose weight. The force produced by the wings that is defined as Lift is really a component of a total force being produced by the wings. The other compent of that force is Drag, which acts opposite to the direction of flight. An equal & opposite force must be applied to counter Drag for the aircraft to maintain its speed. That force is Thrust, produced by an engine consuming fuel.

More weight ==> more Lift required ie more total force from the wings. More total force also means more Drag. More Drag ==> more Thrust required. More Thrust ==> more fuel consumed by the engine to produce that extra thrust.

This applies to all aircraft, however it can be relatively insignificant in small types to being critical in flight planning for large types.

[BOAC]

737-800 typical figures, same altitude (37000')/same speed (LRC), fuelflow/hr

70T 2688kg
65T 2462kg
60T 2270kg
55T 2108kg
50T 1942kg

[siftydog]

Broadly speaking, for an A320 every increase in 1000kg weight at optimum cruise altitude will result in 3-4% increased fuel consumption. It's similar for climb to the same altitude (obviously - the more weight to lift equals more fuel). The curious point is descent; heavier weights mean more fuel burn, but this tends to reflect greater aerodynamic efficiency at a given speed. At 300kts IAS a heavier jet will have a slower descent rate than a lighter one (closer to that sweet spot where the tangent hits the lift/drag curve) thus by taking longer to come down, the heavier jet uses more fuel but travels further in the process. Bit counterintuitive really.