HTX Test Programme

The HTX test programme is a manufacturing and performance ground level demonstration of a pre-cooler type heat exchanger in a high enthalpy (temperature) environment, similar to that expected to be seen by the SABRE engine during its air-breathing flight regime – up to ~1000°C air inlet temperature.

The pre-cooler is designed to absorb over 5 megawatts of heat energy from the incoming hot air passing through it so that the outlet air temperature is just above ambient. Proving the capability and performance of this type of heat exchanger in these extreme environmental conditions opens up the capability of operating at the high supersonic cruise speeds envisaged for the SABRE engine in its air-breathing mode.

The complete test assembly and equipment required to undertake this demonstration was designed, built and assembled by Reaction Engines and its partners at its headquarters in Oxfordshire, UK. Generating the environmental conditions relevant to high speed operation in a ground test facility is possible through the controlled thermal conditions delivered by the TF2 facility in Colorado, managed by Reaction Engines Inc.

Engineers at Reaction Engines’ Culham headquarters constructed the HTX precooler test article and after initial testing it was shipped to Colorado at the end of 2018, and ‘hot’ tests commenced in early March 2019.

See the recent news article here on initial test results.

In October 2019 Reaction Engines successfully tested the precooler at airflow temperature conditions representing Mach 5, or five times the speed of sound, marking a significant milestone in the development of SABRE and paving the way for a revolution in hypersonic flight and space access. To read more about the fully validated test results click here



Test Facility 2 (TF2), Colorado

A new high-temperature airflow test facility located near Watkins, Colorado.

Learn more

Flight applications

SABRE™ engines could allow aircraft to fly much faster than traditional jet engines –  in various conditions.

Learn more


We have developed world leading capabilities in advanced heat exchanger development, design and manufacture.

Learn more