Heritage Concorde

 

 

The “ogival” wing form used on the Concorde is an attempt to modify the optimum delta for greater efficiency at low speeds, particularly at take-off and landings. There was probably more attention given to the design and construction of Concorde’s wing, than any other area of the aircraft. Subsonic aircraft wings may have more than 50 moveable devices, which may include complex flaps, leading edge slats for additional lift at slow speeds, and items for control and trim. Concorde’s “slender ogival delta” wing has none of these and has only 6 “elevons”, which replace the traditional elevators and ailerons for control of pitch and roll

This slender delta has a characteristic not found in other wing shapes. It can fly successfully, producing enough lift, at a wide range of angles of attack to the airflow, up to angles well above those which would cause other wings to stall. This allows Concorde to cope with a wide speed-range simply by changing its angle of attack, rather like a bird does. The built-in ability to increase its lift at high angles of attack enables the wing to delay the stall. The Mechanism which produces this effect is called vortex lift.

 

All swept wings create vortices (swirls of air) at their wing tips. The delta wing, however, as its angle of attack increases (at slower speeds), creates larger, slower moving vortices which creep forward along the leading edge, eventually enveloping the whole upper surface of the wing, thus further increasing the suction and therefore the lift.

If you ever saw Concorde take off, or get a chance to see some pictures of her doing this on a really soggy day, you would see her half-disappear into a cloud of its own making, as the  reduction in pressure forces water vapour supended in the air to condense.

 

 

 

 

 

Vortex lift is fundamental to Concorde’s ability to fly slowly. It also produced one of the characteristic qualities of the feel of Concorde to a passenger. The air swirling over the wing at slow speeds produced a bouncing motion, at a frequency of about half a second, which was sometimes mistaken for light turbulence. The motion soon disappeared once the speed had increased after take-off, but was there during final approach.

Over 5000 hours of wing tunnel testing took place to modify its camber, droop and the twist, this was to ensure that the vortex that would be formed along the wing would be stable at the high angles of attack.

The strength and weight were very important in the design and construction. Instead of bolting and riveting sections together, the engineers used a process known as sculpture milling that starts off with a solid piece of metal. After that they used a numerically controlled milling machine to carve out the required shapes needed. The material used for this was copper based aluminium alloy, known as RR58 in the UK and AU2GN in France.

 

 

Concorde’s  wing  makes sense. There are many features that are different from other airliners. They all stem from the extraordinary range of speeds at which it had to be able to fly, from its ability to take off from Heathrow in the morning, cross the Atlantic at Mach 2, gracefully slow down to join the traffic flow into Kennedy Airport and land in sequence with all the other aircraft

 

Concorde Wing Design

 

The wing was designed and built in France, and can be broken down into nine distinct sections plus a number of smaller parts, that is on paper. In reality five major sections were fixed for life during the construction of Concorde. The big five sections are lateral slices comprising wing/fuselage/wing and together they form the structural heart of Concorde.

In general, the wing is a multi-spar torsion box built up from many comparatively small spar, rib and skin sections bolted together. Most of the spar and rib sections have been machined from billets or forgings, the skin panels from prestretched planks. The panels have integral stiffening webs.

In the forward wing and in the wing section of the centre there are single-web spars where the spars are also fuel tank walls and pin jointed, tubular, lattice ribs set spanwise between the spars. There are no cordwise ribs in the forward wing area, which is attached to three fuselage frames by adjustable fittings (See diagram 1) and to the front spar of the centre section by a double row of countersunk bolts. It incorporates the forward trim tank No. 1

The wing sections of the rest of the centre section each have a few very strong machined spars which extend right across the airframe, as far as the leading edges and outer wings, and numerous cordwise ribs. Inboard of the engine nacelles these ribs are pin jointed tubular lattice frames. Above and forward of the engine nacelles the ribs, in addition to the spars, are machined components.

 

 

The outer wings are torsion boxes of machined spars, ribs and panels. Each is attached to the centre sections by 340 high tensile steel bolts of various diameters. They embody the No.7 main fuel tanks and carry four of the six elevons. The outer hinges of the elevons are designed to permit spanwise expansion. The elevons themselves are honeycomb construction and are connected to each other by flexible joints.

The leading edges are in 4ft sections which are structurally independent to alleviate thermal stress. The chemically milled skins are attached to machined ribs and extruded stringers and all sections are removable.

The numerous inspections hatches in the surface of the wing are either quick-lock or screw fixed and none of them are load bearing.