Design and Fabrication of a Prototype Glider
UCSD's undergraduate aerospace engineering senior design for Spring 2015.
The design problem is to design and fabricate a model glider that will glide further than a model plane of similar size. The objective is to substitute and/or modify different sections of the model plane with intentions of reducing weight, improving lift, and maintaining a streamline body. Two types analysis will be used to examine the progress of the project, first the glide ratio, and second, the wing stiffness.
Before fabrication, conventional gliders were studied and used for inspiration. Hawks, whales, dolphins and sharks were also studied for their streamline bodies, fins, and tails. Distinct differences between gliders and other planes are the high aspect ratio wings gliders have and their low weight.
The first phase of the project was to complete the final prototype wing. First, four initial prototype wings were created of both balasa wood and thin foam with various airfoil designs and aspect ratios. Glide ratio and beam bending were tested for each wing. Balsa wood with a streamline design proved to be the superior design and was chosen as a baseline for the final prototype wing. The final prototype wing was 61 inches long with a constant chord length of 3.5 inches. Balsa wood was used for the skeleton of the wing and mylar was used for the skin. The ribs were modeled after an SD7003 airfoil and fabricated using a laser cutter.
Phase two of the project encompassed design and fabrication of the fuselage and the tail of the glider. The body was made of a solid piece of foam. The foam was first cut with a ban saw, then sanded down with smooth sand paper. The tail wings are made of balsa and was to assist with flight stability. Solidworks Flow Simulation was used for Finite Element Analysis (FEA) on the final prototype wing and XFLR5 was used to study the gliders ideal angle of attack for flight by assessing the glide ratio, which is coefficient of lift/coefficient of drag vs angle of attack.
For the glider to fly smoothly, the moment balance of the plane would need to be at the quarter chord of the fwd wing. Mass was added via quarters to the front of the wing to help adjust the moment balance. Trims were also added to the tail wings to help maintain a smoother flight.
Creating a prototype glider was a successful project. Flight test show an increase in glide ratio with a glider that is nearly the same weight and size as the model plane. The project gives a great sense of what aspects of the initial and modified designs performed well, such as the rigidity of the final prototype wing. The results coincide with material learned in aerospace structures, aerodynamics, and mechanics of materials courses. Future prototypes should focus on weight reduction and mass distribution as these are two crucial factors of flight stability.
Useful number:
Best glide ratio of initial prototype wings: 2.38
Glide ratio of complete glider: 2.86
Weight of complete glider: 0.319 lbs (close to weight of model plane used for initial tests)
The design problem is to design and fabricate a model glider that will glide further than a model plane of similar size. The objective is to substitute and/or modify different sections of the model plane with intentions of reducing weight, improving lift, and maintaining a streamline body. Two types analysis will be used to examine the progress of the project, first the glide ratio, and second, the wing stiffness.
Before fabrication, conventional gliders were studied and used for inspiration. Hawks, whales, dolphins and sharks were also studied for their streamline bodies, fins, and tails. Distinct differences between gliders and other planes are the high aspect ratio wings gliders have and their low weight.
The first phase of the project was to complete the final prototype wing. First, four initial prototype wings were created of both balasa wood and thin foam with various airfoil designs and aspect ratios. Glide ratio and beam bending were tested for each wing. Balsa wood with a streamline design proved to be the superior design and was chosen as a baseline for the final prototype wing. The final prototype wing was 61 inches long with a constant chord length of 3.5 inches. Balsa wood was used for the skeleton of the wing and mylar was used for the skin. The ribs were modeled after an SD7003 airfoil and fabricated using a laser cutter.
Phase two of the project encompassed design and fabrication of the fuselage and the tail of the glider. The body was made of a solid piece of foam. The foam was first cut with a ban saw, then sanded down with smooth sand paper. The tail wings are made of balsa and was to assist with flight stability. Solidworks Flow Simulation was used for Finite Element Analysis (FEA) on the final prototype wing and XFLR5 was used to study the gliders ideal angle of attack for flight by assessing the glide ratio, which is coefficient of lift/coefficient of drag vs angle of attack.
For the glider to fly smoothly, the moment balance of the plane would need to be at the quarter chord of the fwd wing. Mass was added via quarters to the front of the wing to help adjust the moment balance. Trims were also added to the tail wings to help maintain a smoother flight.
Creating a prototype glider was a successful project. Flight test show an increase in glide ratio with a glider that is nearly the same weight and size as the model plane. The project gives a great sense of what aspects of the initial and modified designs performed well, such as the rigidity of the final prototype wing. The results coincide with material learned in aerospace structures, aerodynamics, and mechanics of materials courses. Future prototypes should focus on weight reduction and mass distribution as these are two crucial factors of flight stability.
Useful number:
Best glide ratio of initial prototype wings: 2.38
Glide ratio of complete glider: 2.86
Weight of complete glider: 0.319 lbs (close to weight of model plane used for initial tests)
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