Concorde History III

Though the Concorde has been retired for the past year, the supersonic transport remains a frequent source of questions. This week's article answers several of the questions we have received and is a continuation of those covered in Part I.

One of the greatest challenges aircraft designers confront when building a supersonic plane is the effect of high temperature on the vehicle. These high temperatures are the result of kinetic heating caused by friction between the outside air and the skin of the rapidly moving aircraft. The following diagram illustrates just how hot different parts of the Concorde became at its cruise speed of Mach 2. The skin temperature ranged from a peak of 127°C (260°F) at the nose to 90°C (194°F) at the tail.

Temperature contours on the Concorde during cruise flight
Temperature contours on the Concorde during cruise flight

These temperatures rose even higher at the Concorde's maximum rated speed of Mach 2.2, with a peak nose temperature of 153°C (307°F). If those temperatures aren't impressive enough on their own, just consider that the outside air temperature at the Concorde's cruise altitude of 17,000 m (56,000 ft) is only -57°C (-70°F)!

This external heating had a significant impact on the construction of Concorde. Perhaps the most important issue designers had to contend with was the fact that heat causes materials to expand. I've seen different values on exactly how much the aircraft expanded, but most sources indicate that the airframe stretched by 5 to 12 inches (12 to 30 centimeters) at Mach 2. Given the aircraft's normal length of 204 ft (62.2 m), that change amounts to less than a 5% increase in the size of the Concorde fuselage.

That is not to say that the issue was not a problem. Far from it! The most significant challenge the manufacturers had to address was to select a material that could withstand the heat and expansion while maintaining its mechanical properties throughout the life of the aircraft. Most conventional airliners are built out of aluminum because of its high strength and relatively low weight. Unfortunately, traditional aluminum alloys cannot survive the high temperatures experienced by Concorde. More exotic materials like titanium could have been used, but these are very expensive and often too heavy for use on such a large plane.

The manufacturers instead chose a new advanced alloy of aluminum developed by Rolls-Royce to survive high temperatures. This alloy was known as CM001, CM002, or CM003 depending on the recipe used for the various components. While this aluminum alloy lowered costs and saved weight, it was still inadequate for some areas of severe heating where steel or titanium had to be used.

A further problem designers had to address was the uneven changes in temperature across the aircraft during different phases of flight. This problem was most significant during acceleration to Mach 2 to reach cruise conditions and deceleration prior to landing. These uneven changes in temperature caused some parts of the plane to expand or contract more rapidly than others. This problem resulted in greater stresses and loads acting on the plane's structure at different phases of the flight. Designers were able to overcome these effects by allowing various parts of the plane to move with respect to one another, thereby easing the internal stresses. Examples of these sliding connections included corrugated spar webs, diamond-shaped cutouts, and slotted lug attachments.

While it may seem low-tech, the Concorde's external paint was also chosen to help alleviate the problems of thermal expansion. The white paint was specially developed to help dissipate the heat generated on the surface of the plane at high speed. The paint was also designed to be flexible so that it would not flake off the plane during the thermal expansion and contraction experienced in flight.
- answer by Joe Yoon, 24 October 2004

A total of 20 Concordes were originally built, including test and production aircraft. One Air France model was scrapped in 1994 and another lost in a fatal crash in 2000, but the remaining 18 are currently on display or soon will be.

Concorde being placed on display at New York City in 2004
Concorde being placed on display at New York City in 2004

The following table lists the final location of each Concorde with links to museums or other sites where they are displayed.

Popular Name Registry Operator Location
F-WTSS Sud-Aviation Musée de l'Air et de l'Espace
Le Bourget, France
G-BSST BAC Fleet Air Arm Museum
Royal Naval Air Station Yeovilton
Somerset, UK
01 / 101
G-AXDN BAC / Aérospatiale Imperial War Museum
Duxford, Cambridgeshire, UK
02 / 102
F-WTSA Aérospatiale / BAC Musee Delta
Paris Orly Airport
Orly, France
F-WTSB Aérospatiale / BAC Airbus factory
Toulouse, France
G-BBDG BAC / Aérospatiale Brooklands Museum
Weybridge, Surrey, UK
Air France Crashed in 2000
Wreckage stored at Le Bourget, France
G-BOAC British Airways Manchester Airport Aviation Viewing Park
Manchester, UK
F-BVFA Air France Smithsonian National Air & Space Museum
Steven F. Udvar-Hazy Center

Washington Dulles Airport
Chantilly, VA, USA
G-BOAA British Airways National Museums of Scotland
Museum of Flight

East Fortune Airfield
near Edinburgh, Scotland
F-BVFB Air France Auto & Technik Museum
Sinsheim, Germany
G-BOAB British Airways BAA Heathrow Airport
London, UK
F-BVFC Air France Airbus factory
Toulouse, France
G-BOAD British Airways Intrepid Air and Space Museum
New York, NY, USA
F-BVFD Air France Retired in 1982, scrapped in 1994
Remnants stored at Le Bourget, France
G-BOAE British Airways Grantley Adams International Airport
Bridgetown, Barbados
Air France Musée de l'Air et de l'Espace
Le Bourget, France
British Airways Museum of Flight
Seattle, WA, USA
Air France Charles de Gaulle Airport
Paris, France
British Airways Bristol Aero Collection
Filton, Bristol, UK

Note that some of these aircraft are currently in storage pending delivery to the museums where they will ultimately be displayed. More information can be found at the links provided.
- answer by Molly Swanson, 24 October 2004

I'm afraid that there isn't much work going on in the SST field at present. The Concorde failed because it was too expensive to operate and could not compete with conventional airliners. Since oil prices continue to rise, the poor fuel efficiency of supersonic aircraft continues to hamper airline interest in developing faster aircraft. Neither Boeing nor Airbus is currently working on any SST designs that we know of.

The most likely prospect for a new supersonic passenger plane is not a commercial airliner but a business jet aimed at a very small segment of the flying public. The Concorde's only commercial success came as the result of catering to the wealthy elite who needed to make rapid long-distance trips, so this market is likely to be most receptive to a supersonic replacement. Many aircraft manufacturers believe that a Supersonic Business Jet (SSBJ) could generate strong sales to corporations, private owners, and executive jet services.

Supersonic business jet concepts
Supersonic business jet concepts

The class of supersonic passenger aircraft that is most likely to take the place of Concorde in the short term is small business jets seating about 5 to 20 passengers. It is more economical at this time to cater to a small group of business executives and celebrities than to build a plane capable of carrying 100 or more airline passengers. Airlines are not interested in supersonic aircraft because of their high operating costs, but high-speed travel does appeal to "the rich and famous" or powerful executives who are not nearly as concerned about the bottom line. Business and executive jets are aimed primarily at this clientele to begin with, so that appears to be the most likely market for supersonic travel. A number of aircraft manufacturers have already unveiled SSBJ proposals, including Lockheed Martin, Northrop Grumman, Dassault, Gulfstream, and Sukhoi. A new startup company named Aerion Corp. has announced plans to build a 12-passenger SSBJ by 2011.

Since most nations still prohibit supersonic travel over their territories, particularly over populated areas, these supersonic business jets would most likely operate over the ocean. They would probably be based at large coastal cities and fly between major trans-oceanic centers of business, like New York and London or Los Angeles and Tokyo.
- answer by Jeff Scott, 24 October 2004

Related Topics:

Read More Articles:

Back Aircraft | Design | Ask Us | Shop | Search Home
About Us | Contact Us | Copyright © 1997-2012