An Integrated Three-Dimensional Aeromechanical Analysis of Lift Offset Coaxial Rotors

This paper presents the first use of integrated three-dimensional (3D) aeromechanics modeling, defined as the coupling of 3D solid finite elements based comprehensive analysis (CA) with 3D Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD), to study modern lift offset coaxial rotors. The goal is to demonstrate the development of this methodology and assess its capabilities. The X3D structural dynamics solver is coupled with the UMD Mercury CFD framework for this analysis. Metaltail - a notional hingeless coaxial rotorcraft, developed as an open-access model for the U.S. Army / DoD's High Performance Computing Framework Helios is used as the test case here. The analysis is performed at a low speed transition flight and preliminary predictions of airloads and three-dimensional stresses are discussed. Modern coaxial rotors are compromised by heavy rotor hubs reducing their performance. This paper aims to demonstrate a high-fidelity capability that can help overcome this barrier through accurate predictions of 3D dynamic stresses of blade and hub.