Fuselages to Fusethins. At a time when airlines seek ever less fuel greedy and therefore lighter and more efficient aircraft, we took a look at the fuselages of heavy-weight commercial aircraft, weighing-in at 60% of the maximum take-off weight ! But do you know how thick the outer skin is ? In this consulting design firm specializing in air-frames, they hunt down superfluous kilos on commercial aircraft. Because the more the fuselage of an aircraft is thicker, the more it's heavier, and therefore less efficient. The manufacturers themselves determine the maximum weight for each part of the airframe, which must not be exceeded. Then it's up to the engineers to play around with the thickness, which varies depending on the type of equipment of course, but also the zone where it is located. "We have minimum thicknesses for the A320, thicknesses which can be between 1 and 2 mm, and then the reverse on the bigger planes, such as the A380, which, in areas, can exceed 10 mm ( ½ inch ) ! Near the central part where the wings are attached to the body, the demands will be much more complicated mechanically, therefore, requiring much greater thicknesses." The manufacturers also rely on new stronger and lighter materials ! The fuselages of the Boeing 787, or the Airbus A350, for example, are thus mainly composed of composite materials and carbon fibre has mainly replaced aluminum alloys. "There is an effect on the density of the material. Carbon fibre will have a much better mechanical strength, thus, for the same stress, potentially, we will effectively be able to have less thickness. But once again, it is not in ratios of 1 to 10 or 1 to 100, it still remains within the same ranges." Nevertheless, skimming only a few tenths of a millimetre off the thickness of the fuselage of a short-haul aircraft reduces its mass by between 5 to 10 tons, a reduction of over 10% of its maximum take-off weight ! A slimming down obviously appreciated by the airlines who can carry as much extra in terms of additional passengers or freight, OR simply increase their range !