Simulator study of stall/post-stall characteristics of a fighter airplane with relaxed longitudinal static stability

TLDR

A real‑time, piloted simulation using Langley differential maneuvering data evaluated the high‑angle‑of‑attack behavior of an F‑16‑based fighter with varying relaxed longitudinal static stability, focusing on low‑speed combat maneuvering. The study found that while the baseline control system resisted classical yaw departures, it was vulnerable to pitch departures from inertia coupling during rapid, large‑amplitude rolls at low airspeed and could enter a deep‑stall trim that was hard to recover from, but control‑system modifications markedly reduced inertia‑coupling susceptibility and enabled reliable deep‑stall recovery.

Abstract

A real-time piloted simulation was conducted to evaluate the high-angle-of-attack characteristics of a fighter configuration based on wind-tunnel testing of the F-16, with particular emphasis on the effects of various levels of relaxed longitudinal static stability. The aerodynamic data used in the simulation was conducted on the Langley differential maneuvering simulator, and the evaluation involved representative low-speed combat maneuvering. Results of the investigation show that the airplane with the basic control system was resistant to the classical yaw departure; however, it was susceptible to pitch departures induced by inertia coupling during rapid, large-amplitude rolls at low airspeed. The airplane also exhibited a deep-stall trim which could be flown into and from which it was difficult to recover. Control-system modifications were developed which greatly decreased the airplane susceptibility to the inertia-coupling departure and which provided a reliable means for recovering from the deep stall.