The Maryland Tiltrotor Rig (MTR): Baseline Gimballed Hub

This paper describes the features, specifications, and instrumentation of a new tiltrotor test rig at the University of Maryland, the Maryland Tiltrotor Rig (MTR). The MTR is a semi-span, floor-mounted, optionally-powered rig with a static rotor tilt mechanism, capable of testing proprotors of up to 4.75-ft diameter in the Glenn L. Martin wind tunnel (7.75- by 11-ft section with 200 kt maximum speed). It supports interchangeable hubs (gimballed and hingeless), interchangeable blades (straight and swept tip), and interchangeable spars, to allow a systematic variation of components important for tiltrotor flutter and loads. The baseline rig dimensions are 1/5.26 scale XV-15 or 1/8 scale V-22. The principal objectives are to measure tiltrotor instabilities in cruise and vibratory loads in conversion. Additional objectives are airloads, drive system loads, rotor-wing aerodynamic interactions, and closed-loop control of loads and instabilities. The baseline rig is a gimballed hub. It is complete, all components fabricated (Calspan), parts assembled, sensors integrated, and statically calibrated. The objective of this paper is to describe this baseline rig. The vision behind the rig is to conduct research on future high-speed tiltrotors with an envisioned flutter-free cruise up to 400 kt, enabled by thin wings, and light-weight, low-vibration, high-performance rotors. the features, specifications, and instrumentation of this rig. The purpose of the MTR is to provide a testbed for 1 Introduction basic research on aeromechanics of high-speed tiltrotors. A vision for the next generation of these aircraft is 400 kt A new tiltrotor test facility at the University flutter-free cruise with a turboprop-like thin wing (14% of Maryland has continued to make progress on the thickness to chord ratio) and a lightweight, low-vibration, Maryland Tiltrotor Rig (MTR). The design of the rig high-performance proprotor. The objective of MTR was outlined in Ref. [1]. The fabrication of the baseline is to enable this vision through systematic parametric gimballed hub rig is now complete. This paper describes variation of blades, hub, and wing spar. MTR is a research rig, not a scaled-down version of a particular