A training sailplane design

In this study, the first general three phases of sailplane design, which are requirement defining, conceptual design and preliminary design have been studied and applied for a two-seater electric-powered self-sustaining training sailplane design. The critical performance specifications of two-seater sailplanes existing in the literature have been described and taken into consideration as a starting point. In requirement defining phase, critical objective parameters were tried to be realistically estimated depending on this collected data. General layout of the sailplane was determined at the conceptual design phase depending on advantages and disadvantages of wing, tail and fuselage configurations. In preliminary design phase, with the objective of designing aerodynamically efficient wing, tail and fuselage combination, each of the geometries were optimized to satisfy stability and especially level flight trim conditions by means of numerical analyzes. Trial-error optimization of the wing and tail designs were carried out especially depending on the criteria of having high lift to drag ratio and low induced drag. For this purpose, main wing was tried to be designed to have span-wise lift distribution similar to the elliptical lift distribution. Center of gravity calculations were carried out, its location was optimized and limitations were determined. In the end of the study, the aerodynamic performance parameters of the concluded design were obtained and revealed with numerical analyses. The obtained results were found to be in good agreement with the previous studies.