This Ajax model apparently on display at Farnborough in 1998 looks nothing like any of the others designs. Some of the (poorly auto-translated) text that went with the photo:
"Domestic development - VKS "Ajax" seems more exotic. Nevertheless, it is much more promising than Skylon. The project is being worked on by the “Institute for Research of Hypersonic Systems (MSRI)”, a branch of the St. Petersburg holding company “Leninets” under the leadership of A. Freistadt. The concept was first discussed in the late 1980s, and more often with great skepticism: an unknown Leningrad engineer proposed a whole class of fundamentally new hypersonic and aerospace aircraft based on, as it is now fashionable to say, “revolutionary” design principles."
"Ajax is an open aerothermodynamic system that converts the energy of a hypersonic free flow into work. The authors of the concept propose to reconsider many aspects of the development of [video conferencing](?) of the future. In general terms, the energy exchange goes like this: hydrocarbon fuel (kerosene), passing through channels in the hottest spots of the aircraft (the nose of the fuselage, the leading edges of the wing and the engine combustion chamber), is heated and, through catalysts, decomposes into hydrogen and hydrocarbons with a lower molecular weight. Hydrogen is used in a magnetohydrodynamic converter (MHD generator) to generate electricity used to control the air flow in the inlet circuit of a hypersonic ramjet with supersonic combustion, in which hydrocarbons are burned. The thrust-to-weight ratio of such an engine can be many times higher than this parameter of conventional jet engines, and the resulting electrical energy also goes into the plasma control system for lift and drag of the VKS."
