Flight Data Analysis of the HyShot 2 Scramjet Flight Experiment

TLDR

The development of scramjet propulsion for alternative launch and payload delivery has relied largely on ground experiments for the past 40 years. The study aimed to validate short‑duration ground test facilities by designing the HyShot experiment to achieve supersonic combustion in flight above Mach 7.5. HyShot used a double‑wedge intake feeding two back‑to‑back constant‑area combustors, one fueled with hydrogen at an equivalence ratio of 0.34 and the other unfueled. HyShot 2 successfully followed the planned trajectory and demonstrated supersonic combustion for ~3 s between 35 km and 29 km altitude, while HyShot 1 failed to reach altitude; flight data also correlated reasonably with preflight shock‑tunnel tests.

Abstract

The development of scramjet propulsion for alternative launch and payload delivery capabilities has been composed largely of ground experiments for the last 40 years. With the goal of validating the use of short duration ground test facilities, a ballistic reentry vehicle experiment called HyShot was devised to achieve supersonic combustion in flight above Mach 7.5. It consisted of a double wedge intake and two back-to-back constant area combustors; one supplied with hydrogen fuel at an equivalence ratio of 0.34 and the other unfueled. Of the two flights conducted, HyShot 1 failed to reach the desired altitude due to booster failure, whereas HyShot 2 successfully accomplished both the desired trajectory and satisfactory scramjet operation. Postflight data analysis of HyShot 2 confirmed the presence of supersonic combustion during the approximately 3 s test window at altitudes between 35 and 29 km. Reasonable correlation between flight and some preflight shock tunnel tests was observed.