Shrinking a flight from London to New Zealand to little under 30 minutes might bend the laws of physics. Jack Stewart investigates an ultra-fast airliner concept.
In geography, an antipode of a place on Earth is the point on the far side of the planet, that can be connected to it with a straight line running through the centre. That’s a complicated way of saying that it is as far away as possible.
In the UK, it is often used to refer to Australia or New Zealand, and those destinations are the longest long-haul flights you can take. Flight time with conventional planes from London to Auckland, New Zealand’s largest city, is around 24 hours, with one stop.
Now imagine an aircraft that could do the trip in less than half-an-hour. It could revolutionise air travel, but does it have to break the laws of physics, or at least aerodynamics, to do so?
One inventor doesn’t think so, and he has named his concept supersonic aircraft the Antipode.
“The idea of going from New York to London in, say 20 minutes – that's what I think really grabbed people,” says Canadian designer Charles Bombardier, when we asked him about the many reactions to his concept.
“It's always something that people would like – a transportation system that could take you from one place on the planet to the other side.”
Bombardier is known for his big ideas, and bold concepts. According to his website, the Antipode would be a supersonic business jet that could reach speeds of around 16,000mph (25,600km/h), or Mach 24. For comparison, Concorde reached speeds of a little over Mach 2 (around 1,600mph or 2,560km/h). Apparently it would be capable of taking off from any regular airfield using rocket boosters. These would provide the initial thrust to get the plane to 40,000ft (12 kilometres) and a speed of Mach 5. The boosters would be jettisoned, and a ramjet engine would take over to push the plane to Mach 24.
“I needed to accelerate it to Mach 5 first, as I think the ramjet starts working efficiently at that speed, so I had the idea to use rockets,” says Bombardier.
The rocket boosters would return to the airfield for re-use – a type of recycling that Elon Musk’s SpaceX has recently demonstrated for space launches.
At those incredible speeds the aircraft is more of a hurtling projectile than a conventional plane, and in the conceptual design, the wings reflect this. They would provide enough lift and glide to land on a 6,000-ft-long runway, which is fairly typical. However if the plane needed to make a second attempt at landing it would need to ignite the emergency compact rocket boosters to get back up to speed (Bombardier suggests something similar to these, developed by X-COR Aerospace.) The rocket boosters have a second potential use – they could be used to slow the aircraft down, by pointing them the other way.
Bombardier’s designs for a plane that is 10-times-as-fast as Concorde need to be considered with a sceptical eye, and he admits that this is just a concept, designed to provoke conversation and interest in potential technologies. However he has considered some of the potential problems.
An earlier concept, the Skreemr, was designed to reach Mach 10. The plane would suffer from some of the same problems as Concorde – a loud sonic boom over land, and potentially massive heat build-up along the leading edges of the nose and wing due to air resistance (friction) at high speeds. However after publishing that design, and stimulating conversation, as he wanted, Bombardier was contacted by Joseph Hazeltine, an engineer with Wyle, which provides technical services to Nasa and the US Department of Defence.
Wyle suggested incorporating a new technology known as LPM, or Long Penetration Mode.
Some air would be channeled through a nozzle in the nose, and used to produce a counter-flowing jet of air. The aerodynamic phenomenon could, theoretically, reduce the sonic boom and cool the surfaces by disrupting the airflow. Some experiments in a wind tunnel have already shown it can work.
Even a new technology like LPM will not reduce the heat to zero, and the ramjet engines have yet to be developed to a point where they are commercially useful. The incredible acceleration felt on board may also limit desirability to passengers.
“In the end it's not a practical idea – it's a concept,” admits Bombardier.
However this concept is at least proof of Bombardier’s belief that sharing ideas can promote development.
“I wanted to help get funding to do more research, and so I tried to push the whole thing forward,” he says. “I know that it's not going to lead to the exact aircraft at the end, but it might help to develop new technologies and new processes. If it does, then that I'm happy that I did something to help society.”
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