Towards Integrated design of fluidic flight controls for a flapless aircraft

Abstract

Fluidic flight controls enable forces and moments for flight vehicle trim and manoeuvre to be produced without use of conventional moving surface controls. This paper introduces a methodology for the design of Circulation Control (CC) and Fluidic Thrust Vectoring (FTV) as fluidic controls for roll and pitch. Work was undertaken as part of the multidisciplinary FLAVIIR project, with the goal of providing full authority fluidic flight controls sufficient for a fully flapless flight of an 80kg class demonstrator aircraft known as DEMON. The design methodology considers drag, mass, volume and pneumatic power requirements as part of the overall design cost function. It is shown that the fundamental flow physics of both CC and FTV are similar, and hence there are strong similarities to the design approach of each. Flight ready CC and FTV hardware has been designed, manufactured and ground tested. The CC system was successfully wind tunnel demonstrated on an 85% scale half model of the DEMON. The design condition of a control ΔC L of 0⋅1 was achieved with a blowing coefficient of 0·01, giving a useable control gain of 10. The FTV system was static tested using a micro gas turbine source. The control characteristic was 'N' shaped, consisting of an initial high gain response in a negative sense (gain = -30) followed by a low gain response in a positive sense (gain = +3) at higher blowing rate. CC and FTV control hardware directly contributes to around 6% to the overall mass of the flight vehicle, however provision of pneumatic power carries a significant mass penalty unless generated as part of an integrated engine bleed system.

Numerical study of instabilities and compressibility effects on supersonic jet over a convex wall

“…2008; Crowther et al. 2009; Smith & Warsop 2019; Warsop, Crowther & Forster 2019) and fluidic thrust vector (Flamm et al. 2006; Ferlauto & Marsilio 2017; Li et al.…”

Application of Back-Step Coanda Flap for the Supersonic Co-flowing Fluidic Thrust Vector Control

“…Of the various FTVC methods 4-6 that have been studied to the present, the method to utilize the coanda effect of the secondary flow blowed or bleeded at the nozzle exit becomes one of the subjects of interest. Some previous studies [6][7] demonstrated that the thrust vectoring technique utilizing the coanda effect at the downstream of the rectangular nozzle exit [8][9] works fine to deflect the primary jet's direction to some extents Those results, however, have been limited to control only yaw in relatively low-speed subsonic regions 6,9,10 . Recent experimental 11 and numerical 12 studies regarding on the "co-flowing" FTVC technique also have been limited in revealing the quantitative performance-characteristics of the technique.…”

Flow Control Fallacies: A Review of Commonpitfalls in Flow Control Research

“…Flow control technologies are often proposed as solutions to many problems in aerodynamics including drag reduction [1], high lift system improvement [2], noise reduction [3], and control of low observable flight vehicles [4]. However, despite almost a century of development of flow control techniques, there have been very few long-term applications of successful flow control in production aircraft, perhaps apart from the use of vortex generators (though these are not universally applied).…”