LAPCAT

LAPCAT (Long-Term Advanced Propulsion Concepts and Technologies) was a 36-month European FP6 study to examine ways to produce engines for a Mach number 4-8 hypersonic flight aircraft.

[7] The researchers are looking at an aircraft capable of flying from Brussels (Belgium) to Sydney (Australia) in 2–4 hours,[8] significantly reducing journey times across the globe.

[9] The engine is theoretically capable of powering the A2 to a sustained Mach 5 throughout flight with an effective exhaust velocity of 40,900 m/s or specific impulse of 4170 s, SFC 0.86 lb/(lbf⋅h).

[8] "Results so far show the Mach 5 vehicle from Reaction Engines can avoid later technology pitfalls and could travel from Brussels to Sydney," says ESA's LAPCAT project coordinator Johan Steelant.

Initial studies of a first-stage rocket ejector concept gave poor range with large take-off mass.