Silent aircraft creeps closer to reality

CLICK HERE TO DOWNLOAD DOCUMENT

Today, the vision of quieter and more environmentally friendly flying came a step closer as researchers from Cambridge University and the Massachusetts Institute of Technology (MIT) unveiled their revolutionary concept for a silent aircraft. Originally conceived as making a huge reduction in the noise experienced by people in the vicinity of airports, this highly-efficient design also offers improvements of around 25% in the fuel consumed in a typical flight compared to current aircraft.

The design is intended for the generation after next of aircraft for entry into service in 2030. The design looked at improving the airframe as well as the engines as half of the noise from a landing plane comes from the airframe. Some of the key design features employed are:

• the overall shape of the aircraft which is a single flying wing – this allows the body to provide lift as well as the wings allowing a slower approach which reduces noise and the shape improves fuel efficiency in cruise
• flaps and slats have been eliminated – these are a major source of airframe noise when a plane is landing
• the undercarriage has been simplified and its aerodynamics improved
• the engines are mounted on the top of the aircraft which screens much of the noise from the ground
• novel ultra-high bypass engines, which have variable size jet nozzles to allow slower jet propulsion during takeoff and climb for low noise, and be optimized for maximum efficiency during cruise which requires higher jet speeds.

Dr John Green, Chairman of the Science and Technology Sub-group of Greener by Design said:

“My first reaction on hearing of the Silent Aircraft Initiative was profound scepticism. Three years on, I have to concede that the SAI has surpassed my expectations by quite a margin. The team has produced a high-risk but credible design that is predicted to meet the original target. In retrospect, I ought to have expected a team from Cambridge and MIT, supported by Rolls-Royce and Boeing, to achieve something special. A radical approach to the challenges of the future comes more naturally from Academia than Industry, but the outcome will carry credibility only if the team is sufficiently strong and if it has the support of Industry and access to modern design methods. The SAI team has shown how this can be done”.

The research which led to the design was sponsored by the Cambridge-MIT Institute which has funded a wide range of research and educational collaborations between the two universities. The researchers formed a Knowledge Integration Community (KIC) which included staff and students from both institutions and participants from a wide range of aerospace collaborators which include regulators, airport and airline operators, aerospace manufacturers, other universities and representatives of a community group. The KIC approach has been developed by the Cambridge-MIT-Institute and has been successfully applied in a number of research areas. It is an exciting way to address big problems – and underpins the vital nature of collaboration in achieving the potential for step-change improvements.

Colin Smith, Rolls-Royce Director of Engineering and Technology said:

“The Silent Aircraft Initiative (SAI) has been a great success in bringing many stakeholders together to study what an aircraft of the future might look like if very low noise was the primary requirement”. Describing one of the clear lessons from the project he added: “The teams at Cambridge and MIT have energetically pursued their task and have considered some highly innovative ideas. The study has confirmed that the solution for extremely low noise must be a highly integrated combination of engine and aircraft design and operation”.

This team has not only focused on the design itself but has had a variety of other impacts such as on education, outreach and engagement with industry. Prof Ann Dowling, who led the UK research team said:

“This project has brought industry, academia and other stakeholders together around a ‘grand challenge’ that has captured the enthusiasm and imagination of all partners: there has been effective collaboration, knowledge exchange, and development of a real team approach. The students involved have learnt a lot as members of this integrated product team.”

Prof Ed Greitzer, the MIT lead, also emphasized this point:

“True collaboration and teaming occurred in essentially all aspects of the project. The Silent Aircraft Initiative has been very much an enterprise in which the whole is greater than the sum of the separate parts”

Jim Morris, vice president of Engineering & Manufacturing, Boeing Commercial Airplanes at Boeing said:

“Boeing congratulates the Silent Aircraft Initiative for undertaking a very challenging research assignment. This collaboration has stretched our imagination and generated some noise mitigation ideas that we will be able to study for potential future use."

Notes for Editors:

1. The Silent Aircraft Initiative was funded by the Cambridge-MIT Institute in 2003 as a collaboration led by Prof Ann Dowling at Cambridge University Engineering Department and Prof Ed Greitzer, Aeronautics and Astronautics at MIT. The project, with a grant from CMI of £2.3 million, brings together teams involved in different aspects of aircraft design for a multidisciplinary approach. The Initiative has involved 40 researchers from the University of Cambridge and the Massachusetts Institute of Technology (MIT) all driven by a common cause with a very clear mission.
2. The project has had significant collaborations from all parts of the civil aerospace/aviation industry including: British Airways, BAA, Boeing, Brüel & Kjær, the Civil Aviation Authority, Cranfield University, DHL, easyJet, Eurocontrol, HACAN Clearskies, Lochard, London Luton Airport, Marshall of Cambridge Aerospace, National Air Traffic Services (NATS), Nottingham East Midlands Airport, the Royal Aeronautical Society and Rolls-Royce.
3. Greener by Design is an organization which:
   • Researches, assesses and advises government and industry on operational, technological, economic and regulatory options for limiting aviation's environmental impact.
   • Promotes best practice across the aviation and aerospace sectors.
   • Promotes a balanced understanding of aviation's true environmental impact and its environmental programmes.
   • Holds annual conferences on sustainable aviation.
4. Pictures of the design will be available from www.silentaircraft.org from 6th November.
5. For further information please contact Eddie Murphy (Mobile 07966 404 813, ejmurphy@ntlworld.com)
   

Last updated:06/11/06