Why MZFW?

[fly_boy]

What is the Max. Zero Fuel Weight; is it a structural or performance limitation. Appreciate any deliberation on its application in the operational environment.

[static]

It`s structural; the aircraft is stronger when it has fuel in its wings. It is one of the load limits before flight.

[FlapsOne]

I have often wondered about this one.

So when do we load up with empty wings then?

Would it be theoretically be possible to increase the allowable weight given the caveat that fuel must go in the wings first?

[Checkboard]

Not so much that the aircraft is stronger with fuel in the wings, as a limit on the bending moment at the wing root.

The more weight in the fueslage, when that weight is supported by the wings produces stress at the wing root. Fuel (stored in the wings) has it's weight suported along the wing, and doesn't provide the same bending moment.

[fly_boy]

Thanks fellows.

[Old Aero Guy]

Flaps One

You do get a gross weight credit when fuel is put in the wings. The reduction in wing root bending moment due to wing fuel is accounted for when MTOW is calculated. That's one of the reasons center section fuel is burned prior to burning wing fuel.

MZFW is the weight at which all structural regulations regarding flight load factors i.e. gust loads, maneuver loads etc. can be met. The airplane still must pass the regs. with empty tanks. Remember your 2.5g airplane can have more maneuverability than that with full wing fuel and enough airspeed, provided other bits like the h-tail and the engine mounts are good for it.

[stardust]

MZFW is not used any more!, MZFM,mass, is in force now! it's the same at 1 G !


If it's legal, it must be safe!