Wings and cargo

[chornedsnorkack]

There are obvious advantages to having much of the aircraft in wing. Less bending loads by distributing the weight along the lifting surface, less parasite drag.

Airplanes have their fuel in wing tanks if they can and only have fuselage tanks if they have not enough wing volume. The engines are often mounted on wing rather than on fuselage - again, less structural bending loads. The main landing gear is accommodated in bays inside the wing if possible - having it all in fuselage is difficult.

People, however, like fuselage with windows and evacuation exits.

What about luggage? Is there any strong structural reason why cargo bays for checked luggage and other cargo cannot be made inside the wing?

[Mad (Flt) Scientist]

Access to the wing would be more complex; there's nowehere obvious to put a hatch. (Leading edge is bad for aerodynamic reasons; trailing edge is too thin; top is hard to access from ground; underside is accessible but the hatch is where you'd put the 'floor' of the cargo space, so you'd waste space for the hatch.

Wings are also a strange shape internally, both due to the external aerofoil shape and due to the load-bearing structure throughout the wing. It's relatively easy to put holes in ribs to allow fuel to pass, rather less so for baggage.

Fuel is also easy to distribute in a systematic fashion in the tanks; cargo would be subject to loading variations, with implications for e.g. flutter

You still have to put fuel somewhere, and fuel in the fuselage is a bigger fire hazard, so its also safer to put fuel in the wings and cargo in the fuselage.

A few reasons off the top of my head.

[chornedsnorkack]

Access to the wing would be more complex; there's nowehere obvious to put a hatch. (Leading edge is bad for aerodynamic reasons; trailing edge is too thin; top is hard to access from ground; underside is accessible but the hatch is where you'd put the 'floor' of the cargo space, so you'd waste space for the hatch.
Wings are also a strange shape internally, both due to the external aerofoil shape and due to the load-bearing structure throughout the wing. It's relatively easy to put holes in ribs to allow fuel to pass, rather less so for baggage.
Fuel is also easy to distribute in a systematic fashion in the tanks; cargo would be subject to loading variations, with implications for e.g. flutter
You still have to put fuel somewhere, and fuel in the fuselage is a bigger fire hazard, so its also safer to put fuel in the wings and cargo in the fuselage.
A few reasons off the top of my head.

Ah, I see.
The passenger BWB proposals that make waves now and again have no fuselage at all. Presumably they also have to put fuel somewhere. Perhaps towards wingtips - where the headroom for passenger decks gets limited.

Given that passengers require more headroom than baggage, and more need for windows, emergency exits et cetera, it might be sensible to have a craft with a fuselage that is small relative to wing and holds just the passenger cabin, while the wing contains both cargo and fuel. Aerodynamically, the rear fuselage is useful as a beam to give leverage to stabilizer and elevator forces...