A ground run up enclosure (10) which comprises an air inlet structure (12), a test chamber (14), an acoustic enclosure (16) and a main enclosure door (118). The air inlet structure (12) is adapted to receive ambient air and redirect it into the test chamber (14). The test chamber (14) is designed to receive a portion of an aircraft (20) therein. The acoustic enclosure (16) receives the airflow from the test chamber (14). The airflow continues through the acoustic enclosure (14) until it contacts a front surface of the main enclosure door (118) and is redirected upward and out of the enclosure.