Showing papers on "Wing root published in 1986"
TL;DR: In this paper, the authors compared dual-wing general aviation designs with single-wing designs and showed that with proper selection of gap, stagger, decalage, and mission requirements, total drag can be significantly reduced.
Abstract: Dual-wing general aviation designs are studied and compared with single-wing designs. It is demonstrated that with proper selection of gap, stagger, decalage, and mission requirements, total drag can be significantly reduced. Proper spanwise distribution of decalage is shown to enhance efficiency while raising the critical Mach number. Also, flight conditions have been chosen to result in operation at the proper Reynolds number, reducing the viscous drag even further.
8 citations
TL;DR: In this article, the flowfield is divided into a number of non-overlapped regions, each containing a compon- ent of the aircraft such as a wing, a fuselage or a nacelle.
Abstract: A method has been developed for calculating the flowfield around complex aircraft configurations using upper-surface blowing (USB). The method is based on a zonal grid generation approach coupled with an Euler flow solver algorithm. In this method the flowfield is divided into a number of non-overlapped regions, each containing a compon- ent of the aircraft such as a wing, a fuselage or a nacelle. H-type grids are generated independe- ntly in each region using a hybrid elliptic/ algebraic grid generation scheme. An explicit finite volume Euler algorithm has been developed that is applicable to the multi-region H-type grids. The present method has been applied to a two-dimensional USB model and a realistic aircraft configuration consisting of a wing/ fuselage with two integrated nacelles. Numerical results indicate that the computational method is effective in predicting the flowfield about USB-type configurations and complex aircraft geometries.
2 citations
01 Jan 1986
TL;DR: This paper discusses the use of eigenspace techniques for the design of an active flutter control/gust load alleviation system for a hypothetical research drone that exhibits acceptable performance in situations in which the failure of an actuator is simulated.
Abstract: This paper discusses the use of eigenspace techniques for the design of an active flutter control/gust load alleviation system for a hypothetical research drone. One leading edge and two trailing edge aerodynamic surfaces are available for control. Full state control laws are designed for two combinations of control surfaces by selecting feedback gains which place closed loop eigenvalues and shape closed loop eigenvectors so as to stabilize wing flutter and reduce gust loads at the wing root while yielding acceptable robustness and satisfying constraints on rms control surface activity. These controllers are realized by state estimators designed using an eigenvalue placement/eigenvector shaping technique which results in recovery of the loop transfer characteristics of the full state feedback systems. The resulting feedback compensators are shown to perform almost as well as the full state designs. They also exhibit acceptable performance in situations in which the failure of an actuator is simulated.