Method of a calculation aerodynamic factor of a aircraft with X -wings, having a small span

Аuthors

Burago N. G.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: buragosg@narod.ru

Abstract

The main purpose of the article was the investigation of aerodynamic characteristics of the aircraft wings which have a small span and large solid length along the body. Given characteristics make necessary to develop a new methodology for calculation of the aircraft aerodynamic coefficients.
There was a performed experimental measurement of aerodynamic forces and pitch moments of aircraft models. The experiments were conducted in a wind laboratory of the Moscow Aviation Institute. The experimental results are presented in the form of graphs. The value of the coefficients depends on wings shape, Mach numbers and angles of attack
It was found that the normal force coefficients depend primarily on the wing area. They do not depend on the shape and length of the leading edge of the wing along the airframe. If the coefficients of normal force attribute to the projected area of the wings and body to the wing area, then all aircraft at the same Mach numbers have the same dependence between these coefficients and angle of attack.
It was found that the relative position of the pressure centers of the normal forces of wings with different configurations, expressed as a fraction of the wing chord, depends only on the value of the chord. It does not depend on the shape of the leading edge of the wings and their length along the body. This observation also underlies the coefficients calculation method of the pitching moment.
Studies are limited in Mach numbers from 0.64 to 1.44. The ratio between housing diameter and wing span is limited by 0.16. Some research has been carried out for the flow velocity 47 m/s in the wind tunnel. This limits the range of the calculated value with Mach less than 3. When the diameter of a scale in calculation greater than 0.16 the developed method will be accumulated.
The developed method allows to determine the coefficients of the normal force and pitching moment in very complex layouts aircraft. Other methods do not permit this.
A new engineering method for calculation of the aerodynamic coefficients of forces and longitudinal moment of aircraft is developed. The aircraft has the small X-wings aspect ratio. They fit into a square with sides equal to the diameter casing and they have a bigger extension along the fuselage. Method is simple and accurate enough. Results of calculation are compared with the aerodynamic experimental data. The experiment is conducted by using the wind tunnel of the department for aerodynamics of the Moscow Aviation Institute (National Research University).

Keywords:

calculation method, aerodynamic coefficients, the aircraft, the scheme "X", the body, wings, low elongation, small scale, experiment

References

1. Burago S.G. Aerodinamicheskii raschet manevrennogo letatel’nogo apparata (Aerodynamic calculation of maneuverable aircraft), MAI, 1993, 48p.
2. Lebedev A.A., Chernobrovkin L.S. Dinamika poleta (Flight dynamics), Moscow, Mashinostroenie, 1973, 615p.

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