Circuit de Monaco downhill again to a double right-hander called "Portier," named after region of Monaco, before heading into the famous tunnel, a unique feature of a Formula One circuit. (Until 2009 only one other circuit, Detroit in 1982–88, featured a tunnel, but the F1 series now includes racing at the Yas Marina Circuit in Abu Dhabi, which presents a shorter tunnel at the exit of the pit lane.) As well as the change of light making visibility poor, a car can lose 20–30% of its downforce due to the unique aerodynamic properties of the tunnel. The tunnel also presents a unique problem
Davidstow Circuit 89.88 mph. So Davidstow ended as a motor racing circuit; it has been a short career but by no means an inglorious one. There is a flourishing ultralight and microlight flying school at the airfield today. Davidstow Circuit Davidstow Circuit is a disused motor racing circuit and airfield built in Cornwall, in the United Kingdom. The circuit was built on the site of a World War II RAF Coastal Command base, RAF Davidstow Moor, opened in 1942. Davidstow circuit opened in 1952, and held three Formula 1 races between 1954 and 1955. The circuit hosted its last race in 1955,