Concluding on Five this week is the series that sees Chris Barrie examine a range of machines designed for speed. In the last episode, he charts the development of attack helicopters from the experimental autogyro of the 1920s to heavily armed military models of the 1970s and 80s.

This week Chris traces the history of one of modern warfare’s most potent weapons: the attack helicopter. But to get under the skin of these fast and stealthy flying devils, Chris first takes a look at the humble autogyro, predecessor of all modern helicopters. He takes a ride in this “little mouse of a machine” to find out how such a ground-breaking design was made possible.

The tiny, lightweight autogyro was created by the Spanish engineer Juan de la Cierva in the 1920s as a low-speed craft intended for precision bombing. While it bears a close resemblance to a helicopter, the autogyro differs in that its blades are not powered once it takes flight; instead, they are driven by wind and momentum. The autogyro is able to coast at very slow speeds without falling out of the sky.

However, early versions of the machine were hampered by drag on the blades that caused it to roll on one side. “It was de la Cierva’s solution to the problem that secured the future for all helicopters,” Chris explains. That solution consisted of blades with hinges, allowing them to flap during flight and balance the craft. It was a design that has been employed in helicopters ever since.

Helicopters for commercial use were developed in the 1950s, including the impressive Fairey Rotodyne, a gigantic aircraft capable of carrying 75 passengers at speeds of up to 307kph, but a lack of interest saw the cancellation of the project. It was the involvement of the military, and the switch to jet engines, which ushered in the golden era of helicopter development.

In 1962, the US army debuted the classic Bell Huey UH-1 in Vietnam. This powerful craft could carry 14 troops and mounted machine guns at speeds of 240kph. The Huey, an icon of the Vietnam War, was a breakthrough design, yet its foes soon hit back with effective anti-aircraft weapons. “Attack helicopters would need to get faster and much tougher to survive,” Chris says.

The next generation of helicopter was the Mil Mi-24 or Hind model, which the Soviet army began using in 1973 and remains in service to this day. The fearsome Hind bristles with firepower, including rockets, machine guns and bombs. Measuring over 20m long and weighing up to 12 tons fully loaded, this highly manoeuvrable craft also boasts a 30mm-thick armoured cockpit. It set a world record speed of 368kph in the 1970s. “You could call it a helicopter,” Chris concedes, “but I think ‘flying tank’ would be more appropriate.”

The dominance of the Hind was only challenged by the British outfit Westland in the 1980s. In a bid to reverse their company’s fortunes, a group of engineers decided to push the limits of design by modifying a 1971-era Lynx helicopter into the ultimate speed machine. Using computer models and advanced formulae, they created new rotor blades with revolutionary tips. In 1986, the modified G-Lynx set a world record speed of 400kph, which has yet to be broken.

Chris brings his tour of attack helicopters up to date with a look at one of the best-known modern vehicles. “Combining the heavy armour and mighty firepower of the Hind with the speed and manoeuvrability of the Lynx, you will struggle to beat the truly evil-looking Apache AH-64,” he says. This stealthy craft can hover for hours without overheating, fly just metres from the ground, and slip beneath radar. Its sophisticated controls include an optical eyepiece which relays flight details to the pilot without having to look at the instruments – a useful trick when travelling at speeds of up to 365kph. Chris rounds off the show in style when he gets to take a ride in an Apache belonging to the Dutch Air Force.

Friday 14th March at 7:30pm on five