AS the global population increases, so will the demand for air travel. Not only will the demand increase, the speed by which we travel is expected to also increase as more and more businesses become globalised.
How convenient it would be if passengers from New York could reach London in just two hours. And those from London could reach Christchurch under four hours. This would actually be possible if there were hypersonic planes.
The world has seen supersonic planes before. The Concorde was a British-French supersonic passenger airline that operated between 1976 and 2003. It was called “supersonic” because it could travel faster than the speed of sound. Actually, its maximum speed was twice the speed of sound (Mach 2).
Supersonic usually means going faster than the speed of sound (Mach 1 or 1,235km/h). This barrier was first breached by American pilot Chuck Yeager in 1947.
Boeing, a major American plane maker, last month unveiled its concept design for a hypersonic jet that could travel at Mach 5 or five times the speed of sound (6174km/h). But it’s not the only player in town. Many aircraft companies are looking at hypersonic planes of their own.
Last year, Lockheed Martin announced plans to begin development on the SR-72, a hypersonic military aircraft. Meanwhile earlier this year, China successfully tested its own hypersonic plane in a wind tunnel, where it reached a speed of Mach Seven.
Other companies looking at hypersonic planes include Boom Technology, which is supported by The Spaceship Company, a Virgin Galactic spin-off, and by General Electric; Aerion and Spike. It should be said though that all are at conceptual and testing phase, and production remains a long way off.
Passenger feel
There is a natural perception that if a plane is travelling at such high speeds, it won’t make for a comfortable ride. However, according to experts, passengers won’t feel that much of a difference from what they are experiencing during normal flights today.
Where there will be a noticeable difference is the fantastic view they will have once the plane reaches a higher altitude. Today’s passenger planes typically fly at an altitude of 10,668m but hypersonic planes will go up to 27,432m.
When you fly that high, you can actually see the curvature of the Earth when you look out the window. And if you look upwards, instead of blue skies, you’ll see the darkness of space above. It should be quite a majestic view.
The heat generated will be quite high so it’s been speculated that instead of having real glass windows, such planes will have virtual windows instead, with cameras mounted on the plane’s exteriors and a video feed displayed on monitors placed where windows would normally be located.
The engine system needed for hypersonic planes will be a bit complex and will involve what is called a combined cycle engine. It’s called that because it combines two different cycles. The first is turbine while the second is a ramjet.
The plane takes off using a turbo engine, similar to what is used in today’s planes. When the plane reaches about Mach 3, the turbine engine can’t be used anymore as it would melt at hypersonic speeds. So a transition is made to the ramjet: an air-breathing jet engine that sucks in air.
Commercial viability
The technology for hypersonic flight is sound but it’s not the technology aspect that will prove challenging. It’s the economics of it.
For one thing, the cost of making these planes will be huge. Figures like US$100 million (RM407 million) per plane have been touted. Then there’s the fuel cost. Hypersonic planes will be fuel hogs, burning between five to seven times more fuel than a standard aircraft flying the same distance.
Hypersonic flights will be fast but can they be affordable? One of the reasons the Concorde was eventually cancelled was that it attracted very few customers. If you look at consumer behaviour in general the tendency is to go for no-frills, budget flights. That’s why airlines like AirAsia, FireFly and Malindo are popular. So, you can forget about “normal” people taking hypersonic flights. It just won’t happen.
Presumably the only travellers willing to pay such a premium would be business travellers. But even so, would these same passengers be willing to pay more than what they’re used to in business class today? Whatever the ticket price for hypersonic flights will be, it will definitely be more expensive than business class tickets in today’s planes which are already very pricey.
Another challenging issue has to do with sound. Supersonic planes generate a sonic boom. This was the reason the Concorde was only allowed to fly across water. Hypersonic planes would also generate a sonic boom.
Engineers are working on ways to lessen the noise made by supersonic and hypersonic planes. Nasa has tasked Lockheed Martin, for example, to come up with a Quiet Supersonic Technology aircraft. The basic idea is the plane’s shape would scatter the shockwaves produced at intense speeds so they couldn’t combine to form a loud sonic boom.
Not so soon
Although technologically speaking, hypersonic speeds are very achievable, there are many hurdles to overcome before hypersonic flight can become commonplace. Chief of these would be the cost factor — how do you make it affordable? How do you reduce the need for a lot of jet fuel for both cost and environmental considerations? And then there’s also the need to reduce or eliminate the sonic boom, which is no small matter. This had limited the Concorde’s routes to trips across water.
Boeing scientists are saying it could be 20 to 30 years before its hypersonic plane becomes a reality. The most ambitious projections say we could see a hypersonic jet in operation by 2025 but even that is considered very optimistic.
But when that day comes, it could really change the way business is conducted. Imagine business people making day trips to different continents. A CEO could travel from London to New York early in the morning, have his meeting, eat lunch, and be home in time for dinner with his family on the same day.