Airframe Structure

The Aerospatiale/BAC Concorde airframes were built in 17 main sections, the majority of which were built from a number of smaller sections. Four of the main sections of the wing were built as handed parts, port and starboard. The five big main sections: nose, forward, intermediate, centre and rear, are permanently joined to form a single unit. The basic structure consists of a skin supported by extruded stringers and fabricated hoop frames.The single row of windows extends along each side of the pressurized passenger cabin. Each of the cabin windows comprises a pressure panel and an outer thermal insulation panel. Both of these panels consist of two layers of toughened glass separated by plastic interlayer’s.The lower half of the fuselage is divided into various compartments which accommodate areas for baggage, fuel tanks, the nose and main landing gear and systems components etc. The upper half of the fuselage is occupied by the main passenger cabin, the flight deck and a baggage hold, which also incorporates a diplomatic mail locker.The upper and lower halves are separated by a floor built as a number of sections and supported by a structure. This had been designed to be free to expand longitudinally and therefore minimize the thermal stresses arising from the temperature differences between the fuselage skin and the longitude floor members. The intermediate section of the fuselage carries the under-floor baggage compartment.

The Fuselage

The fuselage is a mainly conventional pressurised aluminium alloy semi-monologue structure of constant cross-section, with unpressurised nose and tail cones. Hoop frame at approximately 0.55 m (21.5 in) pitch support integrally machined panels having closely pitched longitudinal stringers. Window surrounds in the passenger cabin are formed of integral skin-stringer panels machined from aluminium alloy planks. The nose is drooped hydraulically to improve forward view during take-off, initial climb, approach and landing. Retractable visor is raised hydraulically to fair in windscreen in cruising flight. Each engine nacelle consists of hydraulically controlled variable-area (by ramp) air intake, engine bay and nozzle support structure. Reverser buckets, which are also used as secondary nozzle, are actuated by ball-screw jacks driven by compressed air through flexible shafts. Leading-edges of intakes, rear ramp sections and intake auxiliary door are electrically de-iced. Engine nose bullet and inlet guide vanes are de-iced by hot engine bleed air.

The forward fuselage has a passenger door of the outward opening plug type, on the port side, and a service door opposite. It extends from frame 8 to frame 28 and incorporate the nose landing gear bay and a systems bay, which is pressurised, below the cabin floor.The intermediate fuselage, frame28 to 41, incorporates the forward baggage hold below the cabin floor. This is a pressurised hold with an inward opening door in the bottom of the fuselage.

Frames 30, 34, 38 have fittings for the attachment of the forward wing.

The rear fuselage extends aft from frame 72 and incorporates the rear fuel transfer tank (No. 10), the rear pressure bulkhead at frame 81 and a support structure of A-frames, of tubular and extruded members, which carries the fin.

The rear baggage compartment occupies most of this section forward of the pressure bulkhead.

There is a baggage door on the starboard side and below the floor there is an unpressurised bay for electrical and electronic equipment.

The retractable tail bumper wheel is mounted on the rear tank bulkhead.

Nacelles

Concorde has two engine nacelles; each one accommodates two engines and is divided into two structurally independent parts, consisting of air-intakes and engine bays. There is an extension of the engine bay which incorporates the secondary nozzles. The intakes and engine bays are attached to the wing by flexible joints which ensure the complete sealing and continuity of form.

Flight deck

The flight deck, with all its controls, equipment and instruments is within the fuselage nose section, which also carries the droop nose and visor; it incorporates the forward pressure bulkhead and extends aft as far as frame 8. The windshield glazing’s are mounted in a surrounding structure which was machined from plate.

Concorde passenger cabin floor

The passenger cabin floor, this consists of aluminium alloy and balsa sandwich panels supported by cross beams set on the same pitch centres as the hoop frames. These beams are supported by tubular struts also, which are in turn pin jointed to the keel structure of the fuselage except over the main land gear bay, where special machined beams are used. The floor is built in a number of sections free to expand longitudinally to minimise thermal stress caused by differential expansion of the fuselage shell and the fore and aft floor members. Each floor section carries fore and aft seat rails of standard cross section.

The floor does not have to contain the cabin pressure barrier of one form or another is provide (Diagram 1): over the nose wheel bay and the aft systems bay curved membranes are attached to the bottom flanges of the floor beams; the fuel tank roofs have alternative flat and membrane panels which contain the cabin pressure and are stiffened enough to resist the fuel inertia pressure resulting from an upward impact of 15g.There is also a flexible vapour seal between each tank roof and the cabin floor and the spaces between these seals and the tanks roofs are kept at a pressure slightly lower than that in the cabin and are vented to atmosphere.

Centre wing/fuselage sections. In these sections the wing structure is continuous across the fuselage with the top flanges of the spars at the cabin floor level, so that the cabin sits on the wing but is not a separate entity. The fuselage construction is similar to that of the other fuselage sections

 

Taking them in order, forward to aft, section 14 extends between fuselage frames 41 and 46 and incorporates wing spars at these sections. Under the cabin floor is fuel tank No.2 (centre) and in the wing are the port and starboard No.2 trim tanks. Section 15 extends from frame 46 to frame 54, incorporating a wing centre section of the same extent. Under the cabin floor is the main fuel tank No.8 and in the wing are the No.3 fuel collector tanks and parts of the No.4 main tanks. A main wing spar, which is a tank wall also, divides the N.3 tanks from the No.4 tanks at the fuselage sections 50. Section 16 extend from frame 54 to frame 60 and incorporates wing spars at these stations. It is of special construction below the cabin floor level because it includes the main landing gear bay, which is divided on the centre line of the fuselage by a machined keel box which is pressurised and carries service cables, pipes and ducts. In the wing, fore and aft and outboard of the landing gear bay, are parts of No. 4 and No.5 fuel tanks.

 

Section 18 extends from frame 60 to 66 and incorporates a wing section of the same extent. Under the cabin floor is main fuel tank No.9 and in the wing are parts of main tanks No.5 and collect tanks No.6. Another combined wing spar and tank wall, at section 63, divides the main tanks from the collector tanks. The front support links for the engines are attached to this wing section. Section 20 extends from frame 66 to frame 72, incorporating wing spar at these stations and at station 69, the latter being also the rear of the No.6 tanks. Under the cabin floor is part of the aft systems bay, which is unpressurised. The main engine mountings are pin jointed to the spar at station 69 and at the rear spigot mountings for the engine nacelles are attached to the rear spar, to which the inboard elevons are hinged also.

Fin and Rudder

Above: G-BOAA before being moved to Scotalnd with her tail removed

 

RIght: G-BOAA gets her tail re fitted in Scotland

The main section of the fin is built of machined skin panels, machined vertical spars and light horizontal ribs. The spars, ten in number, rise parallel to the rudder hinge line and are riveted to reinforce fuselage frames, of which the seven aft of the pressure bulkhead are combined with full depth A-frame structures. A front fairing, a leading edge and cap fairing complete the fin surfaces. The two-piece rudder, of honeycomb construction, is hung on Teflon self aligning bearing. There is a flexible joint between the two pieces. The fairing on the starboard side of the fin and rudder encloses the main power control unit that on the port side encloses the standby unit.