Letting fly

To rise above the smog and traffic and soar into work in a personal aeroplane is the fantasy of many a harassed and cramped commuter. But the seductive daydream of Jetsons-style personal air travel is already the subject of much serious scrutiny by some of the biggest hitters in aerospace.

Tasked with investigating the feasibility of such a system at Boeing’s advanced R&D wing, Phantom Works, Lynne Wenberg is one person who thinks a Personal Transport System (PTS) could be more than just a flight of fancy.

Nominally based in St Louis, Phantom Works’ virtually networked team of around 4,300 staff supports all aspects of Boeing’s business. More than 800 systems and technology projects run concurrently, ranging from hypersonic flight and the development of advanced UAVs through to advanced avionics and composite aerospace materials. While the results of many of these projects remain strictly in-house as proprietary technologies, Phantom Works also develops technologies for external customers including NASA and the US Defence Department.

As Phantom Works’ senior strategic development manager, Wenberg is responsible for pinpointing the technology gaps that need to be filled before PTS can become a reality. ‘While many of Boeing’s other departments plan in the three to five-year range, we are often looking ahead 20 years or more,’ she explained.

PTS is part of a business development group at Phantom Works called White Space, which looks at future strategic growth areas for Boeing. As befits a high-end, secretive R&D base such as Phantom Works, Wenberg was tight-lipped about many of its current projects.

On the subject of PTS, however, she was more effusive. In her opinion, the concept of personal air transport, however futuristic it may seem, is within reach. Nevertheless, she admitted that there are so many technology challenges that need to be addressed before it becomes a reality that it is difficult to envisage when something approaching a personal air vehicle might be developed.

‘The vehicle portion of the project is just one small piece of the jigsaw,’ she said. ‘There are so many technology barriers that need to be overcome, particularly in air traffic management.’

Studies already undertaken by Phantom Works have shown that the entire air traffic management infrastructure would have to be redesigned to accommodate any form of PTS. Air traffic control would need to be able to handle thousands of aircraft flying at low altitude in densely congested airspace. To do this, precise new 3D navigation equipment is necessary, along with the processing capability to track thousands of aircraft simultaneously.

Wenberg identified a number of key areas in which technology has to catch up with the concept of PTS before it becomes viable. The first, and most vital, is introducing an unprecedented level of safety, reliability and ease of use in the vehicles.

For instance, allowing a newly qualified 17-year-old to manually pilot a miniature aeroplane thousands of feet above a busy city street would just not be feasible. However, Wenberg believes that it would be self-defeating for the PTS to have too much autonomy.

‘The vehicle of the future may not have a pilot, but will more likely have an operator. It will have a lot more autonomy, be a lot more intelligent but at the same time people want to have a sense of independence and be able to direct the aircraft where they wish to go,’ said Wenberg. ‘This means that it will have to be even smarter than fully autonomous. The person behind the controls will be able to make every decision about where they want to go but in a very safe, reliable environment.’

Boeing’s vision is to have a fully autonomous vehicle that travels along a designated flight path but one that also allows the operator to re-engage with it at any time. ‘The “highway in the sky” concept, where the vehicles pass along invisible lanes is one good solution that we have looked at,’ said Wenberg.

PTS would have safety features such as an emergency auto-land function, as well as the ability to process weather reports and detect and respond to any difficult weather conditions.

Another problem for Phantom Works’ engineers is the price. Wenberg is adamant that the PTS should not be a plaything of the rich, and said that she would want it to cost considerably less than $100,000 (£56,000).

To this end, engineers are working on keeping the running and maintenance costs of a future PTS as low as possible. This is leading to research into innovative composite materials that are light and cheap but do not compromise on safety.

Another issue — no doubt familiar to Boeing by now — is countering the negative perception of air transport in terms of its impact on the environment. ‘Some of the biggest technology challenges are in finding an effective propulsion system that is non-polluting and far quieter than the current state-of-the-art,’ admitted Wenberg. The team at Phantom Works is looking into alternative fuels such as hydrogen or all-electric systems to form part of PTS, and propulsion systems with benign acoustic and thermal signatures.

The planned range for the PTS is a maximum distance of 450–900km. Due to its short range, Wenberg envisages that a PTS vehicle would not need to climb much higher than 2,000–10,000ft, making the reduction of noise pollution particularly problematic.

Phantom Works is not the only organisation currently working on personal air transport systems. As reported in The Engineer’s cover feature (20 January 2005), NASA is also investigating the concept of the ‘flying car’. Although Phantom Works and NASA have exchanged notes on certain aspects of their research, Wenberg identified a big difference between the organisations’ approaches.

‘From a vehicle standpoint NASA has a very specific idea of what it wants,’ she said. ‘NASA is looking at conventional take-off and landing and its approach is very vehicle-centric. Our approach is a lot more from a total systems perspective, looking at the technologies that will enable PTS in the future.’

However, clearly the design of the vehicle itself is an integral part of any air transport system and Wenberg admitted that Phantom Works is looking at different technologies that would make a vehicle more secure, including fault-tolerant controls and even in-built pilot health monitoring. While some early prototypes were developed — including a mini-helicopter that could drive on the road — the team decided that the technology that is needed as a baseline for their research does not yet exist.

Lamenting the fact that today’s helicopters are still using the basic technology principles of almost 50 years ago, Wenberg said that some big developments are needed to meet Boeing’s final vision.

The company hopes to develop a craft that can take off and land almost vertically and Wenberg is aware that there is still much research to be done before we will be clambering into our mini-planes to get to the office.

‘At the moment PTS is still just a study — we are defining a future capability,’ she said. ‘We are looking at everything in detail because if this project is not done well, it will just bring its own problems.

‘We have not even ruled out the possibility that an air vehicle might be the wrong direction entirely, but the technologies that will come out of this research can only have a positive impact on the rest of the business as a whole.’