Hush house

A hush house is an enclosed, noise-suppressed facility used for testing aircraft systems, including propulsion, mechanics, electronics, pneumatics, and others.

A hush house is large enough to accommodate an entire crewed or uncrewed aircraft.

Some facilities are also equipped to test additional capabilities such as weight and balance, night vision and low lighting, water intrusion, heat soaking, and wind evaluation.

Engines removed from an airplane can be tested while held in place by thrust frames.

The engine exhaust, after having been thoroughly mixed with cooling air, is generally discharged through a vertical stack.