Sir - The concept of the omnibus owes more to tradition than to talent; if a design works, there is no need to change it. Airbus Industrie aircraft - and Boeing airliners - are low-winged, so Airbus, with its A3XX, abjures the main advantage, which a clean-sheet approach has over that of Boeing, with the 747: that it can opt for a mid-wing design.
I am well aware of the awkwardness of the mainspar passing through the centre of the fuselage. There is an exception, however. When the aircraft is big enough, separate cabins can be employed fore and aft of the spar, with minimal, crew-only, access between them. A single main-bogie unit, shorter because the nacelles are higher, then fits nearly beneath, in unpressurised space, which, nonetheless, is inside the main cylinder.
There is no need for draggy root strakes, either to house the undercarriage, or to reduce wing-body interference, which is already minimised by this choice of configuration.
Can the Airbus designers explain why the A3XX is a low- rather than a mid-winged aircraft?
NOEL FALCONER
Exeter, Devon, UK
Source: Flight International
