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This project was completed as one of my senior capstones and was an investigation into the applications of wing joints on the dynamic stability of an glider. I worked with 3 other engineers to research, design, build, and test a glider with shoulder and elbow joints set to varying degrees to determine if any one wing configuration was more dynamically stable.
This project was completed as one of my senior capstones and was an investigation into the applications of wing joints on the dynamic stability of an glider. I worked with 3 other engineers to research, design, build, and test a glider with shoulder and elbow joints set to varying degrees to determine if any one wing configuration was more dynamically stable.
Wing and Tail Design
Wing and Tail Design
The aspect ratio was assigned based on the aspect ratio of a gull and the Reynolds number we expected to fly at. Manufacturability needed to be kept in mind, so all dimensions were sized to be slightly larger than optimal. For this project, we planned on doing dynamic testing by mounting the glider on top of a car so we could cut down on the scope of the project. As such, a NACA 0014 airfoil was selected for both the wing and tail. After initial testing, the wing size was made even larger to ensure the airfoil profiles were rigid. Sizing for the tail and stability analysis were conducted using Athena Vortex Lattice (AVL).
Wing
Span = 1.0 m
Chord = 0.2032 m (8 in.)
Tail
Span = 0.36 m
Chord = 0.127 m (5 in.)
VH= 0.6, lt= 0.4 m
S.M. = 0.15
Lattice structure of the aircraft in AVL
Wing and Tail Construction
Wing and Tail Construction
The unique part of building this glider is the wing needed to be able to change configuration and the airfoil profile could not change. To achieve this, the wing was separated into four sections. that connected at the elbows and the fuselage. The profile was constructed by 3D printing ribs that would be spaced evenly throughout all wing sections. The airfoils would be connected on two spars, a leading edge spar and a center spar made of aluminum rods for lightness and rigidity. There would be two main joints, one at the connection between the inner wing sections and the fuselage, and another at the elbow, where the outer wing sections connect to the inner ones. The wing would then be covered with a solite skin.
The tail was hotwired from foam using a laser cut mould of the airfoil profile.
Initial wing mockup using wooden dowels, laser cut airfoils, and rubber bands.
Using this base model, the spars can change angle while the airfoils remain parallel to the expected airflow.
The first prototype of the wing used wooden dowels instead of aluminum rods for spars, and 3D printed carbon fiber ribs. After building this initial model, it was determined the carbon fiber was too flexible and ABA was used for the final model.
Testing
Testing
The glider was mounted using a test stand designed and built by one of my teammates. The aircraft was mounted to the test stand at the wing tips, and the center of gravity was selected to maintain a static margin of 0.15 for each wing configuration. To change wing angles, the aircraft skin was cut off and reapplied and the wing angle was manually changed before every flight.
The aircraft was tested at 3 different Re: 80k, 200k, and 450k. The wing angles tested in degrees were 0, 10, 20, and 30.
10deg20mphT1.mp4
Results
Results
To analyze the results, we compared the damping calculated from the aircraft during each test and graphed it relative to the elbow angle. The graph to the left shows all zeta values for an elbow angle of 15 degrees. The different colored dots represent the different shoulder angles tested.
View our final report here:
G21_FINAL_REPORT.pdfPage updated
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