“Two in one” glider concept for unlimited aerobatics and FES-assisted cross-country flying – part 1

Purpose This paper aims to analyze the possibilities and ways of modifying the existing PW-6 glider to obtain its versatile version suitable for unlimited aerobatic and cross-country flight, taking into consideration possible lowering of the cost of the needed modifications regarding the tooling. Moreover, it also aims to estimate the performance that can be achieved through such modifications. Design/methodology/approach The concept of a master load envelope was applied to facilitate the definition of the airframe parts that required strengthening, accounting for various flight missions. MATLAB and the Simulation and Dynamic Stability Analysis (SDSA) package were used to estimate the performances of both full aerobatic and cross-country versions. Computations of necessary aerodynamic characteristics and control derivatives were performed using the PANUKL package. Findings It was shown that the cross-section enlargements were necessary to maintain the airframe strength requirements. Their extent depended on the mission; however, in most cases, the requirements for the full aerobatic version were dimensioning. Furthermore, the required changes were made without tooling redesign, except for the fuselage molds. The estimated performance of the redesigned glider was close to that of a similar two-seater multifunctional glider described in the available literature. Furthermore, the analysis revealed that the implemented modifications haven’t compromised the design from a performance standpoint. Originality/value The results are mainly of a practical importance and can be a guide for designers planning to implement a similar concept. In particular, they indicate aspects that should be analyzed when similar modifications are planned. The use of the “two in one” concept may be of interesting for manufacturers due to the relatively low labor intensity of the product and, consequently, the possibility of offering essentially two different gliders at a cost similar to the cost of one. Moreover, such a concept fits into trend of the sustainable development, especially when the tools modifications are kept to the minor. From the user’s perspective, such a glider can facilitate instructions concerning full aerobatic training and cross-country flying based on thermals.