There are presently about 150 wind tunnels in the UK of which roughly 75 are in the university sector. Owing to the dual funding structure of research in the UK, these receive government support through a HEFCE teaching budget, as well as from funding councils, industry and overseas agencies. This proposal relates to those facilities funded essentially, but not exclusively by research, and not those retained principally to support the teaching mission of individual universities. The basis of the National Facility model is primarily to focus resource on (1) fewer 'outward-facing' national facilities open to all UK-based researchers; (2) institutions demonstrating a symbiosis of facility and expertise and prepared to demonstrate best practice; (3) institutions that demonstrate a clear, on-going commitment to these national facilities. The number of partners in this proposal has been selected to cover a range of strategic facilities, and to match potential take-up of national facilities by researchers working in most areas of experimental aerodynamics primarily within EPSRC's remit. The National Facility will support research addressing multi-sectoral problems, although there is a clear focus on the aerospace sector. The proposal includes low- and high-speed flows (Mach numbers in excess of about 0.6) and justifies a subset of facilities of national importance to form the National Wind Tunnel Facility based at seven institutions.