Flight of the Concorde
One particularly impressive aircraft is the Concorde, which is, in fact, the very plane we’ve boarded on our journey through the programme! Whilst it’s not a military aircraft, Concorde was underpinned and powered by military technology, and it flew faster than many modern fighters. To find out more about these magnificent machines and their capabilities, Chris Smith took a trip to the Imperial War Museum, at Duxford, to speak with aeroplane officianado Peter Halford; they met, literally sitting in the fastest passenger plane that ever flew.
Chris - So my seat belt is securely fastened and the seats aren't terribly comfortable, actually, for what would have been a very expensive ticket. But just please tell us who you are where we are.
Peter - I am Peter Halford, I’m formally the science and technology education officer at the Imperial War Museum, where we are today, sitting inside one of the first experimental Concorde supersonic aircraft. This particular one is very special because not only was it one of the test airplanes, it itself is the fastest airplane to carry passengers there has ever been.
Chris - When you say it's the fastest, as in this aeroplane has broken all the records.
Peter - This one has, yeah, and as things stand it will hold that record forever.
Chris - Now, what was actually involved in getting Concorde as fleet off the ground in the first place, how were planes like this one used?
Peter - This is a passenger airplane, but its history and its antecedents are from military aircraft, and military aircraft engines in particular were used in it. It's a combination of people wishing to fly faster, but also using the technology required in warfare.
Chris - How fast did this plane go?
Peter - Concordes are particularly well known because they’re supersonic, faster than the speed of sound, the speed of sound being somewhere around seven hundred sixty miles an hour. So this would fly faster than that, in fact twice as fast as that.
Chris - Let's talk about actually the aerodynamics of how this aircraft worked. What was special about it, why was it a game changer?
Peter - Well, firstly because it was using military engines, and also the development of the delta wings, so the beautiful shape of the airplane, because that is the most efficient way of having a wing for an airplane like this.
Chris - Indeed, the wings start halfway along the aircraft, and then they extend outwards towards the back, so they’re widest right at the back of the aircraft.
Peter - Yes. In contrast to conventional aircraft at the time, because of the speed. With the speed of sound, a tremendous pressure wave built up. In fact it's quite a sudden change from smooth air passing over an aerofoil wing, through to this shockwave which travels across the wing, and it changes the position of the pressure on the wing, making it very difficult to manoeuvre and control.
Chris - That's if you have a conventional wing. So is that what forced them to have to come up with this very clever design of this swept back delta wing, in order to surmount that problem?
Peter - Yeah, there are a number of solutions to this difficulty. When the pressure wave builds up, it builds up in a sort of cone shape around the airplane from the nose outwards. And if you can make the shape of the front edge of the wing more or less the same angle as the shape of the cone, then that pressure wave is not travelling across the wing, and not causing these difficulties that come with it.
Chris - If we won the clock back right to the early history of when people began to fly. Obviously, those early aircraft are very different than the one we're sitting in here. Talk us through how those early aircraft worked, and how they were engineered
Peter - all the aeroplanes fly in a similar way - lift has to be created over the aerofoil wing. But prior to that, people had attempted to make flying machines by flapping, having observed birds. However, for a human being to try and do what a bird does is impossible. People then, like George Kailey, where observing birds, and noticing that they could continue to fly without flapping their wings. So the aerofoil shape is a mimic of that.
Chris - We take it for granted now that the Royal Air Force has aeroplanes which have weapons mounted on them. But the early planes didn't have any weapons on them, they were really just for surveillance, weren't they?
Peter - Yes. Aircraft initially were for surveillance - a good way to observe the enemy was to get up to a high vantage point. However, with the observation aeroplane you need a nice steady platform so that you can look out of the cockpit and take photographs, sketches and notes and so on. So that's the attribute of observation aircraft that was very different from what we think of as a fighter aircraft now.
Chris - Moving time on a bit, when did people begin to develop things like the Spitfire?
Peter - After the first world war. There were lots of aeroplanes which then became redundant - people started to use them for racing, and those are particularly well remembered series of air races called the Schneider trophy, and three times an aircraft called the Super Marine S6 won that, and the Super Marine Spitfire was an almost direct development from that.
Chris - These are all propeller driven aircraft though, aren’t they. How did the invention of the jet engine change all this?
Peter - The jet engine was what you might call a step change. Suddenly everything was different. The gas turbine was the big breakthrough, and that happened during the Second World War simultaneously in Germany and in Britain, with someone called Vano Hane in Germany, and Frank Whittle in this country
Chris - And returning to the Concorde that we’re sitting in - when this was flying, and it's going at twice the speed of sound, what sort of drag was it experiencing? Because there must be enormous amounts of friction from all that air rushing past.
Peter - Yeah, air is a fluid lots of little molecules rubbing along the aeroplane, and as we know friction creates heat. So at the front of the aircraft it was probably 200 degrees and towards the back is probably getting on for 100 degrees.
Chris - It must have changed the length.
Peter - It certainly did, yeah, it lengthened by about 10 centimeters during its flight.