FUSELAGES FOR AIRCRAFT

Abstract: An aircraft and a fuselage for an aircraft are provided. The fuselage comprises front and rear tapered double curvature skin portions (1, 2) and a central single curvature skin portion (3). Cabin doors (4, 5, 6, 7) are set into double curvature tapered portions (1, 2) of the fuselage in single curvature skin areas (19, 20, 27, 28). The single curvature skin areas are either extensions (19, 20) of the single curvature central portion (3) of the fuselage or comprise "patches" (27, 28) of single curvature skin immediately each surrounding each door in the double curvature tapered portions (1, 2) of the fuselage.

Description: FUSELAGES FOR AIRCRAFT This invention relates to fuselages for aircraft and in particular to fuselages for transport aircraft, ie aircraft adapted to carry passengers, baggage and/or cargo in a cabin or cargo hold defined within the fuselage of the aircraft. It is well known to provide aircraft with a fuselage having a structure supporting an aerodynamic profile-defining skin and defining a cabin therein. The fuselage comprises front and rear end portions each with a tapered aerodynamic skin profile and a central portion which is a tube of substantially parallel-sided aerodynamic skin profile with the cabin extending through the central portion and into at least one end portion of the fuselage. The fuselage will normally include at least two, and usually at least four, entry doors into the end portions of the fuselage. One of the reasons why the entry doors are placed in the end portions of the fuselage which are tapered in section is because there is a requirement for doors to be positioned substantially at the end of the cabin area. This optimises cabin layout for airline use. Such positioning of the doors in the tapered section of the fuselage means that the doors must have a double curvature skin. This in turn means that each door must be individually designed and manufactured, must have an individual set of parts kept for it by the airline for maintenance and repair purposes and must have an individual repair and maintenance schedule. This requirement necessitates a very large additional cost to the aircraft operator over and above that which would be required for a single standardised door for use at all positions in the aircraft cabin. It is an object of the invention to provide an aircraft fuselage which overcomes the disadvantages of the prior art. According to a first aspect of the present invention there is provided an aircraft fuselage having a structure supporting an aerodynamic profile-defining skin and defining a cabin therein, the fuselage comprising front and rear end portions each having a tapered aerodynamic skin profile and a central portion having a substantially parallel-sided aerodynamic skin profile, the cabin extending into at least one end portion of the fuselage and having at least one entry door in that end portion, wherein the said door has a substantially single curvature aerodynamic skin profile. This enables a standardised cabin door to be designed and manufactured and for a single maintenance and repair schedule and spares to be used. The said door may be set into a first area of fuselage skin of substantially single curvature. This first area of skin may provide a surround for the door of no more than substantially 10cm width. One reason for this is to ensure that a frame for the said door is in contact with an area of fuselage skin which matches the curvature of the door. Alternatively the first area of fuselage skin may comprise a continuation of the substantially parallel-sided aerodynamic skin profile of the central portion of the fuselage. In either case the said first area of fuselage skin may then be blended in with the otherwise tapered aerodynamic skin profile of the end portion of the fuselage. The advantage provided by the feature of the first area of fuselage skin being a continuation of the parallel-sided skin profile is that the cabin will thereby effectively be a constant width substantially along its whole length (because the doors are fitted substantially at the ends of the cabin). Hence, rather than seats, sidewall trim and baggage bins provided at ends of the cabin having to be specially designed to fit a decreasing cabin width, these items can now be completely standardised. Additionally, the greater cabin width at the end will allow more revenue earning seats to be fitted in certain configurations and will allow increased floor area for galleys and toilets. Slight aerodynamic and/or weight penalties may be incurred for the aircraft when this feature is used, however it is believed that the increased revenue earning capacity of the aircraft (increased baggage or freight carriage will also be possible) will more than offset any such slight penalties. According to a second aspect of the invention there is provided an aircraft including a fuselage according to the first aspect of the invention. The invention will now be described by way of example with reference to the accompanying drawings of which: Figure 1 is a schematic plan view of an aircraft fuselage according to the prior art, Figure 2 is a schematic plan view of an aircraft fuselage according to the invention, Figure 3 is a schematic side detail view of an aircraft fuselage according to one embodiment of the invention, Figure 4 is a plan view of the fuselage of Figure 3 (one side only), Figure 5 is a view on the arrows V - V of Figure 3 (one side only), Figure 6 is a similar view of an aircraft fuselage to Figure 3 according to a further embodiment of the invention, and Figure 7 is a plan view of the fuselage of Figure 6 (one side only). Referring to Figures 1 to 5 of the drawings. Figure 1 shows a conventional aircraft fuselage having 112 seats. The fuselage has front and rear tapered end portions 1, 2, each having a tapered and double curvature aerodynamic skin profile and a central portion 3 having a substantially parallel-sided and single curvature aerodynamic skin profile. Within the portions 1 to 3 of the skin profile are defined a crew cockpit 8 and a passenger cabin 9. Below the passenger cabin 9 is a cargo hold (not shown) in which passenger baggage and separately contracted cargo may be carried. The cabin 9 has front and rear extremities in the form of front and rear vestibules 10, 11. The front and rear vestibules each have toilets 12, 13 respectively and galley areas. It will be observed that the two rearmost rows of seats 14, 15 on the starboard side and the three rearmost rows of seats 16, 17, 18 on the port side have been reduced to two each from the otherwise standard three. This reduction has of course been caused by the tapering of the rear portion 2 of the fuselage. Five seats are lost compared to what would be available if the fuselage section were not tapered. Doors 4, 5, 6, 7 are set into tapered portions 1,2 of the fuselage. Each has a double curvature skin and is to a unique design. Looking now at Figure 2 according to the invention it will be seen that the portion of the fuselage of constant width is now much longer relative to the total length of the aircraft. The net result is that the width of the cabin 9 is now constant for its whole length. All four doors 4, 5, 6, 7 are now standardised and have single curvature skins. Vestibules 10, 11 are now constant width throughout with the result that the front vestibule 10 has considerably more working space in the galley area and that the toilet 12 is somewhat deeper. The rear vestibule 11 has considerably enhanced floor space over the prior art vestibule shown in Figure 1. More importantly however the revenue earning capacity of the aircraft is considerably enhanced because five extra seats in rows 14, 15, 16, 17, 18 are now allowed. In addition the cargo carrying capacity of that portion of the cargo hold in the rear tapered portion 2 of the fuselage is now constant width throughout at the horizontal centreline of the aircraft. This additional width may mean that a further one or two standard cargo containers can be fitted within the hold rather than reduced size cargo containers. This provides the benefit that not only can more baggage or cargo be carried but further standardisation of cargo containers may be possible with all the consequential benefits thereof. Yet a further advantage of the invention as shown in Figure 2 is that all seats, sidewall trim and overhead stowage bins can be completely standard. Special versions of all of these would be required for the rear tapered portion 2 of the prior art fuselage of Figure 1. Considerable manufacturing cost savings can thus be enjoyed when fitting out the fuselage of the invention. Looking now at Figures 3, 4 and 5, front and rear tapered portions 1 and 2 and single curvature central portion 3 of the fuselage are again shown. However Figure 3 in particular shows first skin areas 19, 20 of single curvature which surround doors 5 and 6. these skin areas are extended from the central portion 3 of the fuselage into the front and rear tapered portions 1 and 2 to create fuselage portions which have skin sections partially tapered in areas 21, 22 and partially single curvature in areas 19, 20. Parallel dotted lines 23, 24 indicate the conventional extent of central portion 3 of the fuselage. Dotted lines 25, 26 in Figure 4 indicate conventional fuselage taper. Referring to Figure 5 marking 20 indicates the extent of the single curvature skin section in rear tapered portion 2 of the fuselage. Referring to Figures 6 and 7 it can be seen that the central single curvature portion of the fuselage 3 has not been extended into the tapered portions 1, 2 in this embodiment. Here the doors 5, 6 which have single curvature skin are each set into first areas of single curvature skin 27, 28 of some 10cm width which immediately surround the door. The significance of thelOcm width is that it should be sufficient to accommodate a standardised door frame to sit behind this sidth of skin. More or less than 10cm may be required for this purpose. It will be appreciated that in order to blend in the single curvature skin areas 5, 27 and 6, 28 into the surrounding double curvature skins of the tapered portions 1, 2 that a transition area of skin is necessary. These transition areas of skin 29, 30 are shown entirely schematically in Figures 6 and 7, ie no attempt has been made accurately to represent the shape of these areas. Those skilled in the art will appreciate that these areas 29, 30 will be quite irregular in shape which will depend entirely upon the particular relative skin curvatures concerned. This embodiment of the invention will not provide the advantage of increased floor and ceiling space of the embodiment shown in Figures 2 to 5, however all the cabin entry doors can be standardised with a single set of parts being held as spares and with only one door design being required. In addition the frame for the door can be standardised as this too will be in abutment with the single curvature first areas of skin 27, 28. Complex door shimming to ensure a pressure-tight fit is thus avoided.

Claims: CLAIMS 1. An aircraft fuselage having a structure supporting an aerodynamic profile-defining skin and defining a cabin therein, the fuselage comprising front and rear end portions each having a tapered aerodynamic skin profile and a central portion having a substantially pa-rallel sided aerodynamic skin profile, the cabin extending into at least one end portion of the fuselage and having at least one entry door in that end portion, wherein the said door has a substantially single curvature aerodynamic skin profile. 2. An aircraft fuselage as in Claim 1 in which the said door is set into a first area of fuselage skin of substantially single curvature. 3. An aircraft fuselage as in Claim 2 in which the first area of skin provides a surround for the said door of sufficient width to accommodate a standardised door frame thereagainst. 4. An aircraft fuselage as in Claim 2 in which the said first area of fuselage skin is a continuation of the substantially parallel-sided aerodynamic skin profile of the central portion of the fuselage, the said first area being blended in with the otherwise tapered aerodynamic skin profile of the end portion. 5. An aircraft including a fuselage according to any one of Claims 1 to 4.

Inventors: ALLWRIGHT STEPHEN EDWARD, SHELTON WAYNE PETER, ALLWRIGHT, STEPHEN, EDWARD, SHELTON, WAYNE, PETER
Applicants: ALLWRIGHT STEPHEN EDWARD, BRITISH AEROSPACE, SHELTON WAYNE PETER, ALLWRIGHT, STEPHEN, EDWARD, BRITISH AEROSPACE PUBLIC LIMITED COMPANY, SHELTON, WAYNE, PETER
Application year: 1997
Main classification: B64C1
IPC codes: B64C1