February 13th, 2008The idea of modifying the front end of a hypersonic vehicle is not new and dates at least to the late 1950s but at that time proposed methods included forward-facing rocket exhaust and water. Revived in the 1980s from physics brought to wider attention through the SDI programme, tests conducted at the Rensselaer Polytechnic Institute, New York, demonstrate enormous benefits t rout such a system. Tests confirm that a plasma torch could provide in oblique shock that would give an air vehicle traveling at Mach 25 an aerothermal environment equivalent to the conditions a conventional aircraft would experience at Mach 3. However, an aero-lens vehicle, or flying saucer, has even more potent capability. The saucer-shape aero-lens can control the precise angle of deflection of the oblique paraboloid to adjust it so that the shock wall passes over the rim of the saucer at 1/20th of its diameter. By doing this, the air between the shock wall and the rim of the vehicle is compressed, increasing the density on the forward-facing surface of the rim and accelerating it significantly as it flows across the edge to the rear face of the rim. This energy can be used to propel the vehicle at enormous rates of acceleration, supplementing onboard propulsion.
In a novel way, the plasma spike and aero-lens vehicle combine to optimize the shape and the flow pattern for magnetohydrodynamic (MHD) propulsion, a true hyper-velocity airrider capable of speeds in excess of Mach 50. If fitted with a rectenna on its inner surface, protected by a shell transparent to microwaves, the aero-lens craft could pulse electric power through ionized air and propel itself via superconducting magnets placed around the circumference of the ring to accelerate air rapidly over the lip of the edge. Silent, the vehicle would emit a bright, incandescent plasma glow as it accelerated, dodged and weaved at anything up to Mach 50+ in the dense air of low altitude or the rarefied atmosphere at the edge of space. As yet little has been done to determine the effects of superheated air itself becoming a plasma ball within the expanding electric sheath – and serious effects may be experienced which would modify the aerothermal environment in which the craft is operating. Rensselaer's Leik Myrabo has worked intensively on the plasma spike with Moscow's crack mathematician Yuri Raizer from the Russian Academy of Sciences and believes pulse detonation wave engines (PDWEs), researched heavily and tested by the SDI Office during the 1980s, would find application here. PDWEs could be employed to accelerate the aero-lens vehicle to supersonic speed at which point the MHD fan engine would cut in to raise rim pressure by at least 35 atmospheres and literally explode the air at the rim of the craft and kick it to super-drive with a potential velocity of Mach 50. âÃ¶
Perhaps there is a good reason for saucer shaped craft. We can now go faster than Mach 3.3, but our technology may imitate the aliens in 50 to 100 years. Even the mysterious Aurora spy plane, if it exists, is believed to cruise at speeds ranging from "only" Mach 5 to Mach 8 at 100,000 ft (30,510 m) –Aerospaceweb. At Mach 50, however, you could fly around the world (24,901) in under an hour, or from LA to London in 8.6 minutes.