Effect of number of ribs and spar load ratio on the wing mass for light aircraft

This paper presents a calculation process for the estimation of the gross mass of a twospar wing, due to the influence of a number of uniformly distributed ribs along the span. The proposed method is only suitable for preliminary design of light aircraft wings, particularly when the design engineer does not have a clear conception of the dimensions nor a detailed layout of the internal wing structure. The calculation process is developed for a simple rectangular wing model with an unstiffened skin. The estimation of the effect of the number of uniformly distributed ribs on the gross wing mass is based on the calculation of the minimized dimensions of the internal structural components of the wing, i.e. spar booms, spar webs, skin and ribs. Results are presented for three different spar load ratios.