Design and Analysis of a Droop Nose for Coanda Flap Applications

Abstract

The present study describes the fundamentals of droop nose design for improving the aerodynamics of airfoils with active high-lift using an internally blown Coanda-type flap. The main objectives are to increase the stall angle of attack and reduce the power required by the high-lift system. A two-dimensional sensitivity analysis explores the effects of varying airfoil camber and thickness in the first 20% of the chord. The resulting droop nose configuration improves the maximum lift coefficient by about 20% and increases the stall angle of attack by around 10-15 deg. A target lift coefficient of about 4.7 is reached with 28% less jet momentum coefficient, compared to the clean nose. As the modified leading-edge geometry presents different stall mechanisms, the aerodynamic response to variations of jet momentum is also different. In particular, for a jet momentum coefficient above 0.035, the stall angle of attack increases with jet momentum, in contrast with the behavior observed with the clean nose.

Adaptive Nonlinear Flight Control of STOL-Aircraft Based on Incremental Nonlinear Dynamic Inversion

“…As a consequence, a nonlinear controller stabilizing this instability is essential. The latter and other aerodynamic effects were previously researched [1,[5][6][7][8] and are briefly presented in section III.…”

Optimal sensor placement using machine learning

“…The high-lift configuration, shown in figure 9, is a modified DLR F15 airfoil equipped with a highly deflected Coanda flap and a droop nose. The details of the airfoil design are described in Burnazzi & Radespiel [23] and Jensch et al [24], where the objective was to accomplish high lift coefficients during take-off and landing. The leading edge geometry was reached after an iterative process that improved the airfoil stall behavior, which is ruled by the suction peak.…”

Flight mechanics model for spanwise lift and rolling moment distributions of a segmented active high-lift wing

“…In order to introduce the basic functionality of this highlift system, the blown flap technology used in the SFB 880 and its influence on the aerodynamics of a wing are explained in this section. Figure 2 shows a sketch of the wing profile and how the blowing system can be implemented, based on results of research activities in the SFB 880 [13][14][15][16]. The special shape of the knee of…”