the sentinel r1 is a modified bombardier global express powered by two rolls-royce br700 turbofan engines. the programme involved five aircraft and eight mobile ground stations (six on wheeled all terrain vehicles and two in air transportable containers), and a training facility at raf waddington. the programme cost £850 million, as budgeted. the support contract is for 3200 flying hours per year and between 2015–18 the fleet of five aircraft will have average running costs of £54.4m/year.