Big, Bigger, Biggest: Episdoe 3

Tuesday 11th August 8.00pm

Continuing this week is the factual series that examines the evolution of modern engineering. The third instalment explores the leaps in aviation technology that led to the development of the world’s largest cargo plane – the Antonov An-124. Weighing in at 392 tons, the Antonov An-124 can carry tanks, trains and even other aircraft to the farthest corners of the globe. The pinnacle of modern aeronautical engineering, this gigantic cargo plane owes its existence to nearly 100 years of innovation.

During World War I, just ten years after the first aeroplane had taken to the skies, Russian aviator Igor Sikorsky realised that a craft capable of carrying bombs would sell well to the fledgling Russian air force. However, the best engines of the day could produce barely enough thrust to lift a pilot, let alone tons of explosives. Sikorsky’s solution was to mount four engines onto the wings of a craft, as opposed to one in the centre. “It may seem obvious now, but at the time putting four engines on an aircraft was an extraordinary idea,” explains aviation expert Kieran Daly. On 10 March 1915, Sikorsky’s five-ton Miromets flew into enemy territory and dropped 45 bombs onto a German railway station.

To go beyond the capabilities of the Miromets, it was necessary to revolutionise wing design. To provide the rigidity necessary for take-off, early biplanes had two sets of wings supported by struts and cables –which in turn created drag. The longer the wing, the greater the drag – such that heavy planes would never get off the ground. In order to cope with the vast amount of mail moving between Berlin and London in the 1920s, German engineer Hugo Junkers set about designing a plane with a single wing. The wing of the Junkers G-38 was two metres thick, but its streamlined shape and aluminium shell meant it could cut through the air with ease, despite its 21-ton bulk.

The next step was to make planes safe enough for large numbers of passengers. In 1936, Pan American airlines wanted to run the first commercial service across the Atlantic, so issued a challenge to engine manufacturers. Boeing’s solution was to design an aeroplane that could also function as a boat. The 38- ton Boeing Clipper had luxurious cabins, a hull, an anchor and wings. In 1939, the Clipper completed a flight from Baltimore, Maryland to Foynes in Ireland. The safety of the Clipper got its first real test in 1947 when a commercial flight was forced to crash-land in the sea. Despite huge waves, the Clipper managed to stay afloat long enough for all the passengers to be rescued. “It’s a great tribute to Boeing’s design,” says Kieran Daly.

With World War II came the need to transport cargo across Europe as quickly as possible. The Germans relied upon the Messerschmitt ME 321 glider, but this craft had big limitations. Without wheels or engines, each 321 could only make a single one-way journey. In order to turn the 321 into a useful cargo plane, German engineers had to fit it with big engines, permanent wheels and serious suspension. The result was the 43-ton Messerschmitt Gigant.

For the 349-ton C-5 Galaxy of the 1960s, the challenge was unloading. Used by the US Air Force to transport military equipment to hostile territories during the Cold War, the Galaxy had to unload while airborne. But opening a cargo door during flight puts incredible pressure on a plane’s fuselage. Designers got round this problem by fixing a second sealed fuselage to the top of the craft, making a rigid backbone capable of coping with enormous downforces.

On the back of these incremental developments, the Antonov An-124 was developed in 1982. It is 67 metres long and 20 metres high. Thanks to its rigid fuselage and four turbofan jet engines, it has a payload of 150 tons – 25 per cent more than the Galaxy – and can travel some 15,000km without refuelling. It is currently the largest aeroplane in the world. “In flight it is the most extraordinary sight,” says Kieran Daly.

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