Abstract. The flight of a high-speed aircraft (HSA) at constant cruise speed along the line of sight is accompanied by heat generation. The recovery temperature at the fairing’s critical point can exceed 700 °C, which necessitates the use of a material that preserves its structural integrity while maintaining the specified radiofrequency (RF) performance. Material for the fairing is selected by determining the tensile strength and elastic modulus as functions of temperature and load. Most experimental heating chambers employ tubular electric heaters (TEHs) with spiral filaments. In a cylindrical chamber the TEHs are positioned at equal distances from the characteristic heating zone of a standard specimen, producing a concentrated infrared radiant flux in the target area. The through-thickness temperature gradient in this zone is minimal, enabling assessment of material behavior at a prescribed temperature. However, when one-sided heating of the chosen material as part of the fairing assembly is performed simulating thermal exposure from the oncoming airstream, the through-thickness gradient in the half-wave wall differs markedly from that produced by uniform, omnidirectional heating of a standard specimen. Since the purpose of ground tests is to reproduce in-flight temperatures and loads, an excessive gradient mismatch precludes obtaining reliable results. If heating is applied by a high-enthalpy, high-velocity jet, the through-thickness gradient in the half-wave wall becomes closer to operational conditions, which is essential for ground testing. In addition to surface temperature effects on the fairing, it is necessary to reproduce the service load at the most critical structural feature – the joint of dissimilar materials. Load simulation at this joint is implemented using a tie-rod system that generates a bending moment at the clamped (fixed) support. Under exposure to a high-enthalpy high-speed flow, the tie-rod structure may fail prematurely due to reduced strength, therefore local heating of the material interface – excluding the tie-rod attachment – is advisable. Local heating of the fairing assembly is carried out with TEHs using the same methodology as for standard specimens. The key challenges in local heating are reproducing the required through-thickness temperature gradient in the half-wave wall and accurately measuring the true temperature of the RF-transparent section.

Keywords: simulation of oncoming air flow, polymer composite material, high-speed aircraft

For citation: Kudryavtsev D. V. Behavior of an RF-transparent polymer composite in a non-axisymmetric fairing of a high-speed aircraft under simulated oncoming airflow. Aerospace Engineering and Technology. 2025. Vol. 3, no. 3, pp. 458–472. https://doi.org/10.52467/2949-401X-2025-3-3-458-472. EDN QWPPBC (In Russian)