Achievements Obtained for Sustained Hypersonic Flight within the LAPCAT-II project

TLDR

Hypersonic airbreathing vehicle design is highly complex, and LAPCAT‑II focuses on Mach 5 and Mach 8 aircraft, with the Mach 8 scramjet flight deemed feasible but requiring further refinement. The project aims to reduce antipodal flight times to less than 2–4 hours. The study numerically and experimentally assessed performance of a Mach 5 pre‑cooled turbo‑ramjet vehicle, conducted aerodynamic and propulsive experiments, verified wind tunnels across Europe, and validated high‑speed aerodynamics and propulsion models to evaluate integrated vehicle performance. Validated tools confirmed that the integrated vehicles meet mission goals, and the impact of emissions on climate was evaluated.

Abstract

The design of hypersonic airbreathing vehicles is a challenging objective due to the intrinsic complexity of propulsion-airframe integration in combination with an engine cycle design able to operate over a wide Mach number range. This is one of the objectives of EC co-funded project LAPCAT-II aiming to reduce antipodal flights to less than 2 to 4 hours. Among the several studied vehicles in the preceding project LAPCAT-I, only aircraft designs for Mach 5 and 8 flights were retained in the present project. Starting from the available Mach 5 vehicle and its related pre-cooled turbo-ramjet, assumed performance figures of different components were now assessed in more detail numerically and experimental. Though the cruise flight of the Mach 8 vehicle based on a scramjet seemed feasible, further refinement was needed. In support to the integrated vehicle design, dedicated aerodynamic and propulsive experiments were done for the different components as well as for the complete vehicle. This included also the mutual verification of the windtunnels within Europe. In parallel, modelling implementation and validation on high-speed aerodynamics and propulsion were performed. The validated tools gave confidence to assess the performances of the fully integrated vehicles to comply with the mission goals. Finally, the impact of the emissions onto the climate was evaluated.