A Generic T-tail Transport Airplane Simulation for High-Angle-of-Attack Dynamics Modeling Investigations

Abstract

A preliminary simulation of a generic T-tail transport airplane configuration has been developed at the National Aeronautics and Space Administration Langley Research Center. The primary purpose of this piloted simulation is to assess aerodynamic model fidelity requirements for training airline pilots to recognize and recover from full-stall flight conditions in a T-tail airplane. As a result, significant flexibility has been designed into the flight dynamics model. The flight dynamics model is based on newly acquired static and dynamic stability and control data from sources that include: wind tunnel, water tunnel, and computational fluid dynamics. Preliminary results for initial stall show an unstable stall pitch break (if the stick pusher is inhibited), un-commanded motions due to stall asymmetries, significantly reduced dynamic roll stability, and decreased control effectiveness. Preliminary studies indicated an insensitivity to the fidelity of the pitch damping model.

Evaluation of Unsteady Aerodynamic Effects in Stall Region for a T-Tail Transport Model

“…A more comprehensive approach would involve calculating 𝜏 1 and 𝜏 2 using a formal identification method to ensure the best fit between experimental and modelling result [6,22], but this is beyond the scope of the paper. It is worth noting that the values of 𝜏 1 and 𝜏 2 are similar to those obtained in [17] based on CFD simulations of the NASA Common Research Model (CRM) wing-body configuration. The aerodynamic model structure for the normal force coefficient in [17] was identical to (7-8) and the considered wing-body configuration excludes the interference with the horizontal tail.…”

“…It is not possible to directly translate these frequency and amplitude dependencies into time simulation of free flights involving arbitrary motions. This can be partially resolved by replacing the dependence on the frequency 𝜔 with the dependence on the angular pitching velocity 𝑞, as was done in [17,19].…”

“…As the name suggests, the GTT represents a generic mid-size regional jet airliner with a T-tail configuration. Its aerodynamic data were collected from a series of low-speed sub-scale wind tunnel and water tunnel tests, and some preliminary results have been reported in recent conferences [17][18][19]. Computational fluid dynamics was also deployed to estimate the influence of the Reynolds number on the measured aerodynamics data, allowing the pitching moment and pitch damping data to be adjusted to represent the equivalent full-scale aircraft.…”

“…We use both conventional bifurcation analysis and the nonlinear frequency response to examine the sensitivity of stall and post-stall behaviours to the choice of unsteady modelling method: quasi-steady or unsteady. The GTT uses wind tunnel test data by NASA and Boeing [17][18][19] from both static and forced oscillation tests, resulting in a nonlinear but conventional (quasi-steady) flight dynamics model. We then augment the quasisteady GTT model with unsteady aerodynamics effects using the state-space method (sometimes referred to as the Goman-Khrabrov model in the literature) [4], so as to compare the two aerodynamic modelling techniques and validate the capability of the state-space approach in matching the forced oscillation test results.…”

Verification of a Motion Cueing Strategy for Stall Recovery Training in a Commercial Transport Simulator

“…All data shown in Fig. 3 are generic, non-proprietary, and were derived from public sources [16,17]. The roll damping stability coefficient data in Fig.…”