Analysis of a Wing–Fuselage Biplane with Trailing-Edge Flaps in Low-Speed Flow

Abstract

In this paper, the low-speed aerodynamic characteristics of a basic wing–fuselage supersonic biplane incorporating trailing-edge flaps are assessed using both wake and balance measurements. The effects of the flap attachment location, flap deflection, and flap length are evaluated. These experiments employed a flow velocity of and a Reynolds number of , along with a model having a simple three-dimensional wing–fuselage supersonic biplane configuration; and wake data were obtained with a five-hole probe. Installing the flap near the wingtip was found to produce strong interactions between the wingtip and the flap vortices in the wake, leading to significant induced drag at the wingtip. The local lift increases not only at the flap attachment location but also over the entire wingspan. Positioning the flaps near the body is determined to be more effective, and it gives rise to higher lift and smaller drag than in the case of installing the flap near the wingtip, due to the effects of the tapered wing configuration. The effects of the flap length and flap deflection are also confirmed, with longer flaps and larger flap deflection giving higher lift and more drag.