Begul may be more successful in attracting investment than Perth, Western Australia-based Sadleir VTOL Aircraft. Since about 1991, the firm has been marketing unconventional VTOL aircraft. Sadleir's designs show vertical lift being provided by a ducted fan housed horizontally within a delta wing. This exhausts through underwing ducts with rotating vanes which Sadleir's drawings indicate would be connected to a "joy stick". In forward flight, upper and lower doors would close to provide a conventional aerofoil. Sadleir foresaw vehicles with top speeds exceeding Mach 1, and gross weights reaching 50t.
Although copious, the technical literature failed to gain the unanimous endorsement of aerodynamicists and aeronautical engineers. Sadleir did, however, produce and circulate video footage of tethered trials of a small model of the lifting device. These revealed convincingly that the device's thrust exceeded its weight. Lately the company has not been contactable.