Reaction Begins Building U.S. Hypersonic Engine Test Site
Dec 18, 2017 Guy Norris, Aerospace Daily & Defense Report
http://aviationweek.com/space/reacti...us-hypersonic-
engine-test-site

Curious. I've only ever known this to be a European endeavor. From
above:

Construction of the facility follows the award earlier this year
of a U.S. Defense Advanced Research Projects Agency (DARPA)
contract to test the engine?s pre-cooler heat exchanger, or HTX.
The test work, which is due to start in 2018, will focus on
running the HTX at airflow temperatures in excess of 1,800 deg F
(1,000 deg C), representing inlet conditions at Mach 5.

Ah yes, DARPA. I always thought this technology would make for an
excellent (military) air-breather. The heat exchanger, in particular,
isn't useful in vacuum. There is a point when the SABRE engine gets too
high in the atmosphere and ceases to pull in useful amounts of air, so
its inlets are closed and the engine switches to "pure rocket mode"
using store LOX.

I still seriously doubt we'll ever see a Skylon launch itself into orbit
with a useful payload. IMHO, we'll see a fully reusable (liquid fueled
rocket powered) TSTO long before even a prototype Skylon makes orbit
(likely with zero useful payload).

I don't doubt that we'll see SABRE engines powering (likely unmanned)
hypersonic reconnaissance aircraft and/or hypersonic cruise missiles.

Jeff
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