Jetstream 31 national flying laboratory: Lift and drag measurement and modelling

Abstract

Lift and drag flight test data is presented from the National Flying Laboratory Centre, Jetstream 31 aircraft. The aircraft has been modified as a flying classroom for completing flight test training courses, for engineering degree accreditation. The straight and level flight test data is compared to data from 10% and 17% scale wind tunnel models, a Reynolds Averaged Navier Stokes steady-state computational fluid dynamics model and an empirical model. Estimated standard errors in the flight test data are ±2.4% in lift coefficient, ±2.7% in drag coefficient. The flight test data also shows the aircraft to have a maximum lift to drag ratio of 10.5 at Mach 0.32, a zero lift drag coefficient of 0.0376 and an induced drag correction factor of 0.0607. When comparing the characteristics from the other models, the best overall comparison with the flight test data, in terms of lift coefficient, was with the empirical model. For the drag comparisons, all the models under predicted levels of drag by up to 43% when compared to the flight test data, with the best overall match between the flight test data and the 10% scale wind tunnel model. These discrepancies were attributed to various factors including zero lift drag Reynolds number effects, omission of a propeller system and surface excrescences on the models, as well as surface finish differences.

Unsteady aerodynamics analysis and modelling of a Slingsby Firefly aircraft: Detached-Eddy Simulation model and flight test validation

“…The flow vector was set as (1, 0, 0), i.e., in the positive x direction, as the model was set at an angle of α to this axes. The boundary conditions applied were based on several studies performed on an aircraft [20], [22], [21], [23]. At the inlet, outlet and far field, pressure far field boundary conditions were applied.…”

Unsteady Detached-Eddy Simulation (DES) of the Jetstream 31 aircraft in One Engine Inoperative (OEI) condition with propeller modelling

“…The total mass of the aircraft, equated to lift is known, given the Zero-Fuel Mass (ZFM) of the aircraft, fuel and passenger masses. From previous work by Lawson et al [11], the error band ranges in measuring mass, density, speed and angle of attack are presented in Table 2. Table 2: Estimated errors in mass and flight measurement [11] Furthermore, with the known mass of the aircraft and through previous validation of the propeller thrust measurement [11], the errors in lift and drag coefficients from the flight test data are estimated (see Table 3).…”

“…It has been recognized in Johnson's work (2003) [3], how in these latter 30 years, CFD started to assume a more relevant role in the development of new generation aircrafts. For example, CFD investigations for aerospace applications were extensively carried out recently by Ekaterinaris (2004) [4], Kyrkos and Ekaterinaris (2012) [5], Kontogiannis and Ekaterinaris (2013) [6], Gómez et al (2014) [7], Ghoreyshi et al (2016) [8], Kontogiannis et al (2016) [9], Nelson et al (2017) [10], [11], Misaka and Obayashi (2017) [12], and Righi et al (2018) [13].…”

“…Since, unsteady flow problems are in the centre of research interest for aerospace applications, see, e.g., in the works of Jacquin et al [22], Huang and Ekici [23], Ghoreyshi et al [24], and Ghoreyshi and Cummings [25], therefore, the concept of the DES approach offers a potential possibility to investigate unsteady flow around an aircraft. Further CFD investigations in conjunction with the DES technique were carried out recently by Bunge et al (2007) [26] Aircraft simulations and flight testing are playing a key role to support our understanding of flight physics and aerodynamics [11,[35][36][37][38][39][40]. Therefore, several experimental and computational aerodynamics studies on the Jetstream 31 aircraft (see Figure 1) have been carried out in the National Flying Laboratory Centre (NFLC) at Cranfield University in the last decade.…”

Conceptual Design and Performance Optimization of a Tip Device for a Regional Turboprop Aircraft

“…Published flight test data for the Jetstream 31 of the National Flying Laboratory Centre (NFLC) [33] has been used to validate the VSPAero model. The actual flight test data have been best represented by the following equations for the lift and drag coefficients:…”