The Concorde - The World’s Fastest Airliner

The first official discussions started around a committee table in 1954, although I was reliably informed (in person no less) by world-renowned test pilot Eric Brown, that the concept started several years before that. 

Following the first official report on the subject in 1955 and after several further years of research, late-night discussions, and I'm sure a lot of head-scratching, two leading aerospace companies joined forces to adopt the project and take it forward. These were of course the British Aircraft Corporation (BAC) and Aérospatiale, and the year... was 1962! 

With this new partnership prominently in place, the name Concorde was chosen as a nod to this very public collaboration, it means ‘agreement’, and was offered to somewhat symbolise union between the countries. 

Supersonic thinking problems

It’s fair to say there were some real brain teasers to overcome as the concept progressed, and some ingenious feats of engineering yet to be found. One large design feature was the delta wing. An incredible design involving a huge number of complex achievements along the way, but it did present a problem; the pilots couldn’t see the runway on landing. 

The 'slender' delta wing was chosen as it was not only very efficient during transonic and supersonic flight, but it could also produce lift at a wide range of angles of attack which is a somewhat key feature when landing a 100+ passenger seat aircraft (which not long before was flying supersonic!). It achieves this by exploiting ‘vortex lift’ which is essentially the wing energizing the layer of air above the top surface, this results in a drop of pressure due to vortex generation created with a high angle of attack. And this was essential in order to maintain lift at the high nose attitude the aircraft needed for landing. 

Now taking a step back for a second, you can’t miss the very streamlined ‘needle’ shape design of the fuselage (as was required for supersonic flight) and in particular that long thin dart-like nose. The problem was if you kept that dart pointing straight out and proceeded to land the aircraft with the high angle of attack necessary to slow this speedbird down, the pilots literally couldn't see where they were going! So, a rather unflattering sounding 'droop nose' was offered as the solution; on approach the distinctive profile of the aircraft was altered by hydraulically lowering the nose so the pilots could see the runway ahead. 

This incredible wing design went through some 5,000 hours of wind tunnel testing before the team finalised the complex relationship of camber, droop, and shape of the wing. During that phase, It was learned that ‘vortex lift’ generation was improved by having as long a wing as possible, therefore the Concorde wing was designed to extend along almost the entire length of the fuselage. 

For anyone that’s seen Concorde either in person, or even just in a picture, one can’t help but appreciate the planform design, the same as we do when we see the beautiful elliptical wing of the Spitfire. And this too was a much-debated topic during wind tunnel testing, with the final design chosen as an 'ogee' type shape which is responsible for that beautiful soft, and sort of, swept snake like curve to the leading edge of the wing when viewed from above (well more likely below, at 60,000 ft cruising altitude there weren’t many ‘views from above’!). 

And the wing wasn't just a stunning design of aerodynamic achievement but also an engineering masterpiece that was home to many smart thinking solutions, including the first commercial [airline] use of a fly-by-wire flight control system. 

Another feature I find fascinating, and a great Concorde fact; the aircraft got longer during flight. It grew! And not just be a couple of millimeters, but up to a whopping 12 inches! Due to aerodynamic heating (skin friction) the fuselage stretched. In fact, VNE (max speed) was a function of maximum allowable aircraft surface skin temperature, which on Concorde was limited to 127 °C. To counter the heat the aircraft used special highly reflective paint, and that droopy nose I mentioned earlier also included a heat shield to cover the cockpit window. 

The sound barrier

The speed of sound is ‘around’ 760 mph at sea level. I say ‘around’ because it obviously varies with the usual influence of temperature and pressure. At Concorde’s cruising altitude of 60,000 ft where the air is considerably thinner, the speed of sound is closer to 660 mph. So, at its cruising speed of 1,340 mph (that’s 22 miles per minute by the way!) it was flying at over twice the speed of sound. 

But when an aircraft reaches the transonic speed range of the sound barrier, the wing’s centre of pressure shifts aft. Whilst the design team incorporated factors into the design of the wing to reduce this, there was still an undesired shift of about 2 metres. Use of normal subsonic solutions would be the application of trim controls, but this would be a bit of an issue at very high speed, so instead, the flight engineer moved fuel between three ‘trim tanks’ to counter the change of C of G during acceleration (and deceleration) of transonic speeds. 

Mount (an) Olympus

So, we have covered the wings, the speed and a droopy nose. What about power? How much thrust do you need to reach well over 1,000 mph carrying an average of 100 passengers on board? And how does an engine intake deal with a supersonic airflow?? Let’s take a look. 

Well firstly, engines have a bit of an issue taking supersonic airflow into the compressor. So once more, some very clever men and women in white coats carrying clipboards got to work. Basically, a major design requirement was to slow engine intake air down during the supersonic cruise phase of the flight. They achieved this through a very clever engine air inlet design which incorporated variable ‘intake ramps’, these could control intake shockwaves and slow things down to the desired subsonic speed whilst increasing air pressure (called ‘pressure recovery’). 

The engine selected for the Concorde was the mighty Rolls-Royce/Snecma Olympus 593. An engine that could produce 38,000 lbs of thrust with reheat (yes – it had afterburners!) And there were four of them! 

The reheat was only used at take-off and to pass through the sound barrier on its way to supersonic cruise. Once in the cruise, the reheat could be switched off. But (there’s always a but!) whilst this type of engine was efficient at Mach 2.0, it was less efficient (considerably) at low speed. In fact, the aircraft burned two tonnes of fuel just taxing out to the runway!

The summer of 69!

It turns out that the year 1969 was a pretty special calendar to have on the wall if you were keeping track of aviation milestones, for just a few months ahead of Neil and Buzz landing on the moon, Concorde took to the skies on its maiden flight, this was March 2nd to be exact from Toulouse, France and again on April 09th of the same year from Bristol, Filton in the UK. The aircraft quickly proved itself unquestionably as it reached speeds of up to 1,354 mph. To put that into context, that is around 800 mph faster than a Boeing 747 and over 350 mph faster than the earth spins on its axis! It was even said to be faster than a rifle bullet! 

The first supersonic transatlantic crossing happened a few years later in 1973 and the aircraft went into service commercially on January 21st, 1976. Probably the best-known and most iconic of all the routes to be added was London to New York which appeared on the schedule from 1977. 

20 aircraft were built in total, of which 14 went into commercial service: seven for British Airways and seven for Air France. And the Concorde enjoyed almost 30 years of incredible service. It could reach New York in under 3.5 hours, in fact, it still holds the record for the fastest Atlantic crossing of a commercial aircraft at 2 hours, 52 minutes and 59 seconds (recorded on a New York to London flight on February 7th, 1986). 

The Concorde was retired formally in 2003, still in the shadow of the terrible Air France crash in July 2000, and following a number of economic reasons, differences in travel needs during more modern times, and a number of other publicly debated reasons. 

The last commercial flight was on October 24th, 2003, flying from New York to London. And the absolute final flight was a month later landing at Bristol Filton on November 26th to a much adoring crowd, who had spread themselves along every part of the route one might expect to capture a glimpse of this iconic aircraft. 

As we have said a few times during this last year of the Historic Section, there are several iconic aircraft in Aviation, and Concorde is without doubt right up there at the top of the list (well there are about 5 aircraft in joint first place for me!). Not only is it just a beautiful sight to behold and a wonder of engineering, but it achieved supersonic travel for thousands of passengers. It made the impossible ‘possible’. Concorde is an aircraft to be incredibly proud of, it is jaw-dropping in terms of performance and how it’s incredible designers and engineers achieved what they did. 

If you are interested in becoming more acquainted with the type, I highly recommend a visit to one of its homes. There are several Concordes you can go and hunt out, such as the superb exhibitions offered at the Brooklands Museum near London and the Imperial War Museum at Duxford. There is also a fine example at the Runway Visitor Park in Manchester and at the excellent Aerospace Bristol facility, another at the National Museum of Flight in Scotland and one of the all-important prototype Concordes at the Fleet Air Arm Museum at Yeovilton. Not to mention the one parked up by the threshold of Runway 27L at Heathrow! And if that’s not enough choice, you can also find six in France, one in Germany, three in the USA and if you fancy some sun at the same time; there’s one in Barbados! 

I normally finish with “yes, you can fly one”… but sadly this time around that’s not possible. But certainly, you can go and see one. So whilst perhaps, an unexpected addition to the ol’ Historic Section, and the fact it arguably has a wheel at the wrong end (i.e. nose not tail!), hopefully, you agree it’s most fitting and deserves to be here given its outstanding contribution to Aviation History and certainly, it is one very special aircraft to sit back and admire!