Overview: This project focused on designing a high-performance glider tailored for long-range flight by integrating aerodynamic insights using tools like OpenVSP and XFoil. My design incorporated a high aspect ratio wing, carefully selected airfoils, and chose incidence and twist angles to reduce drag and increase lift.
Background:
OpenVSP is a computational tool used for three-dimensional modeling of the aircraft, enabling detailed analysis of geometric parameters such as twist, taper, and incidence.
Objective:
Develop a glider design tailored for flight range and endurance by optimizing wing geometry and airfoil performance, ensuring high lift-to-drag ratios and positive static stability.
Methodology:
I researched high-performance glider design to inform my glider's geometry (Fig. 1), featuring a high aspect ratio (wing span divided by chord length is ~18), a mild sweep angle (5°), and a low taper ratio, with an incidence angle of 4.5° at the wing root and a 1.5° twist at the tips to promote uniform lift distribution. I then used XFoil to generate performance curves (CL, Cd, Cm, and CL/Cd versus α from –5° to 12°) for my selected airfoils—NACA 4415 at the root and NACA 4416 at the tip—analyzing critical performance metrics such as the angle of maximum lift-to-drag ratio (around 6–7°) and assessing the influence of flow separation (Fig. 2, 3). I then performed a body force and stability analysis by calculating aerodynamic forces and moments by hand using CFD data, determining the center of gravity (CG) and center of pressure (CP), and verifying that the CP is positioned slightly aft of the CG (approximately 0.006m difference) to ensure positive static stability. A 3D flow field visualization from SimScale further confirmed the smooth pressure distribution around the wing.
Key Results:
The glider’s wing design, with an aspect ratio of ~18, mild sweep, and optimized twist, was predicted to yield uniform lift distribution and low induced drag.
XFoil analyses for the root and tip airfoils revealed maximum Cl/Cd near 6–7° angle of attack, indicating that the chosen airfoils are well-suited for efficient, long-range flight.
The aerodynamic force analysis showed that the calculated center of pressure (≈1.083 m from the nose) is nearly aligned with the center of gravity (≈1.077 m), confirming positive static stability, which is essential for reliable glider performance.
The 3D flow visualization supported these findings by displaying a smooth pressure gradient around the wing without significant flow separation (Fig. 4).
Conclusion:
My aerodynamic evaluation demonstrates that the glider design is tailored for flight range while ensuring stability. The high aspect ratio and tuned incidence and twist angles contribute to a high lift-to-drag ratio, while the close alignment of the center of pressure and center of gravity confirms inherent pitch stability. These results provide a robust basis for further refinement and potential real-world prototyping of this endurance glider.
Overview: For my graduate Aerodynamics course, I analyzed the aerodynamic performance of several airfoil configurations—including the NACA 2018 series, a series of NACA 24xx airfoils, and a custom-designed foil—using XFoil. The analysis focused on pressure distribution, aerodynamic coefficients, and boundary‐layer behavior over a range of angles of attack.
Background:
XFoil is a computational tool that predicts airfoil performance by solving the boundary-layer and inviscid flow equations to yield parameters such as CL (lift coefficient), Cd (drag coefficient), and Cm (moment coefficient). In this analysis, the behavior of the boundary layer (including separation points) and performance curves (e.g., CL and CL/Cd vs. angle of attack, α) are critical for assessing how geometric modifications influence overall aerodynamic efficiency.
Objective:
Identify the aerodynamic characteristics (pressure distribution, CL, Cd, Cm, and CL/Cd) of the NACA 2018, NACA 24xx, and custom airfoil configurations and quantify the effects of geometry (including camber, thickness, and twist) on lift generation, drag, and flow separation.
Methodology:
I used XFoil to generate Cp(pressure coefficient) distributions for the NACA 2018 airfoil at 0° and 10° angles of attack, from which I tabulated aerodynamic coefficients (Cl, Cd, Cm) and examined boundary layer development to identify flow separation regions. Next, I generated performance curves (CL, Cd, Cm, and CL/Cd versus angle of attack from –5° to 12°) for a set of NACA 24xx airfoils at a Reynolds number of 3×10⁶, analyzing how variations in airfoil thickness affected efficiency. Finally, I compared a custom-designed airfoil—featuring increased camber, a shifted maximum camber location, and a thinner trailing edge—with a baseline NACA 4412, evaluating the differences in lift performance over a limited range of angles.
Key Results:
NACA 2018 Analysis: At 0° angle of attack, the airfoil produced modest CL values with minimal separation, while at 10°, the pressure difference between the upper and lower surfaces increased substantially—yielding a CL of 1.2657 versus 0.1942 at 0°—and clearly demonstrated more pronounced flow separation toward the trailing edge (Fig. 1).
NACA 24xx Performance: The performance maps indicated that, above 0°, thinner airfoils achieved higher CL/Cd at lower angles, whereas thicker airfoils improved CL/Cd at higher angles (Fig. 2); specifically, NACA 2418 yielded a peak CL/Cd of approximately 123.85 at 6.5° and NACA 2412 provided the best average CL/Cd of about 70.48 over 5°–12°.
Custom Foil Evaluation: My custom airfoil (Fig. 3) achieved an average CL of approximately 1.50 (for α from 2° to 7°) compared to 0.976 for the NACA 4412, attributable to its greater camber and thinner profile, which led to more aggressive flow redirection and enhanced lift generation.
Conclusion:
The NACA 2018 results validate expected trends in pressure distribution and boundary layer behavior, while the NACA 24xx study elucidates the trade-offs between airfoil thickness and efficiency. My custom airfoil’s enhanced performance demonstrates that deliberate modifications in camber and thickness can yield superior lift characteristics. These insights provide a strong technical foundation for designing high-performance airfoils in aerospace applications.