1015. Preliminary Weight Estimation of Canard Configured Aircraft

Paper

Abstract

This paper develops a method for preliminary estimation of canard influence on surfaces and fuselage weight. The method is specifically developed for integration into the semi-analytic weight estimation methods used in the Vought Integrated Weights Analysis System. Canard effects on surfaces and fuselage load distribution are based on a mathematical model determined by correlating wind tunnel test results with aerodynamic theory. There are other methods available (such as the Air Force Datcom methods or wing tunnel testing) which predict the loading characteristics of canard configured aircraft. However, when deriving preliminary weight estimates from a limited data base such as a three view drawing, these higher order methods become unsuitable due to both the amount of information and time required for their use. Thus, the method in this paper is intended to fill the gap between design initiation arid detailed design evaluation. It is emphasized that the utilization of the aerodynamic theory is not meant to be a potential flow field analysis but is used as a measure of the effects of the geometric characteristics of the canard wing system on the load distribution between the canard and wing.
As no applicable wind tunnel data in the transonic region of flight was available during the development of this method, a linear variation between the high subsonic and low supersonic cases was assumed (preferred over any higher order of educated guess).
The weight estimation methods referenced in this paper are the Vought semi-analytical methods for the fuselage, horizontal tail and wing. A numerical example is included for cookbook use.