Semester

Spring

Date of Graduation

2012

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

James Smith

Abstract

The main objective of this research was to design and develop a planform shape for a single passenger, unpowered, subsonic glider that relies on gravitational forces for momentum. The wing structure and aerodynamic shape optimized the benefits of near-ground flight (i.e. the increased lift and decreased induced drag), and as a result reduced the overall aircraft weight and wingspan, and enhanced the maneuverability of the craft.;The design faced many challenges as a result of flight in the ground effect regime. There were natural instabilities, primarily in the longitudinal direction that caused the glider to pitch up. In addition, the wing size needed to be minimized in order to contain flight to the ground effect regime while maintaining enough lift to generate flight for a given rider.;An initial straight wing design was developed to determine if a ground effect vehicle without specialty aerodynamic features (such as wingtips, dihedral, twist, etc) could be created. As a result, a basic glider was designed that had a 10.6 ft root chord length with a wing span of 18 ft; this design accommodated the physical requirements of a pilot while maintaining acceptable but limited maneuverability.;In an effort to enhance aerodynamic performance, above that achieved by a straight wing design, variations in the planform shape were examined computationally in ground effect. These changes were inspired by the wing structures of birds that utilize ground effect for a large portion of their flight regime such as seagulls and pelicans. The modifications include twisting and curving the wings in an effort to vary the frontal areas and arc the wings towards the ground plane. The optimal design configurations were then tested experimentally in the subsonic wind tunnel, at reduced Reynolds number, to verify the performance characteristic trends and compared with the predicted CFD and analytical results.;Results indicated that 10% twisted wings produced the greatest improvement in the lift profile as compared to the baseline straight wing design of the glider while in ground effect. This allowed for a reduction in the overall size of the glider by 4.5% which allows for an overall reduction in weight and a decrease in the wing span allowing for an increasing in the banking angle and thus an increase in the maneuverability.

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