Aviation Week

A novel hybrid hypersonic propulsion system combining superconducting electrical power, a gas turbine, ram/scramjet and magnetohydrodynamic (MHD) technology is being developed by California-based startup HyperSpace Propulsion.

The turbine-based combined-cycle (TBCC) engine is designed to power a hypersonic vehicle from a standing start to speeds of Mach 8-plus and could be adapted to commercial and military applications ranging from high-speed aircraft to missiles, as well as potentially space launch systems, the developer says. The baseline concept is an outgrowth of a hybrid electric-gas turbine configuration unveiled in the 2010s by HyperSpace sister company HyperMach for a proposed Mach 5 business jet dubbed HyperStar.

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Although development of the initial hybrid civil engine concept has taken longer than hoped, HyperSpace says the recent increase in interest in hypersonic technologies by the U.S. Defense Department has injected fresh impetus into the new TBCC derivative version. “We have the support and the focus now for our efforts,” says HyperSpace CEO Richard Lugg. “If we are successful with an electric-hybrid scramjet, we have a product that could become a naval weapons program, and at the same time we can maintain our
trajectory toward a commercial hypersonic program with the full TBCC Hyscram engine.”

The company’s commercial designs have most recently focused on a Mach 6.65 airliner concept sized for 200 passengers and a range of 10,600 nm. Provisionally targeted at entry into service in the early 2030s, the design is configured with four 190,000-lb.-thrust commercial derivative Hyscram hybrid
turbofan ram/scramjet MHD engines, which share some of the same fundamental design features of the military TBCC concept.

The core of the Hyscram (hypersonic hybrid superconducting combustion ram accelerated magnetohydrodynamic) engine is a turbofan configured with a magnetically levitated fan and compressor and turbine stages, along with a series of axially mounted superconducting power generators. As each rotating stage is held in place with active permanent magnet air bearings the design requires no mechanical support shaft, oil system or gearing. A plasma combustor generates an ionized flow, which along with exhaust gas, is accelerated by a four-ring MHD electromagnetic augmenter device at the back
of the engine.

Circumferentially enclosing the core is an array of nine dual-mode ramjet/scramjets arranged in segmented ducts. Air is admitted to the ram/scramjets by a translating inlet spike or cone. This resembles the design used in the Mach 3.3-capable Lockheed SR-71 which moved fore and aft depending on fight condition. When the electrically actuated spike is fully forward, the airflow is directed to the ramjet/scramjets, and when retracted the bulk of the flow is diverted into the power-generation turbine core. The “three engine cycles—turbine core, ram/scramjet and MHD thrust” are therefore never fully disconnected, Lugg says.