Scale Model
From Wpi-kites
Goal
The Kite power mechanism is a physically large device. This simple fact makes it very difficult to use this model as a demonstrative figure.
A 1/4 scale model of the mechanism was created as to address this problem. This scale model is ideal for use in classrooms or presentations, as its small size allows it to be easily transported almost anywhere.
The basic model has two different configurations, one allowing for the mechanism to be hand powered and one allowing for wind to power it. The wind powered system is ideal for demonstrative purposes, as it showcases the general movement of the full device. The mechanical system is designed for locations where wind power is not piratical or possible.
Hand powered model
The hand powered model is a system that represents much of what the actual full-scale kite-power generator does.
Sliding Bar for Angle of Attack
The hand-powered scale model contains a bar with a slider to mimic the sliding weight angle of attack change mechanism on the full scale model. When the arm is raised, the weight will fall, pulling the trailing edge of our parafoil down, thus stalling the kite.
Power Train Analog
A power train has been added to the 1/4 scale model to mimic the power conversion system on the full scale model. When the arm is raised a string is pulled around a shaft, and the friction between the string and shaft causes the shaft to spin. When the arm is lowered, the string's reel-in mechanism loosely pulls the string back and does not apply significant friction to the shaft. The shaft also contains multiple flywheels to help store rotational energy. This allows the system to continuously rotate in one direction, just like the full scale demonstrator.
The shaft is connected to a gear train. This gear train leads to a high speed shaft which will soon be connected to a small DC generator. This generator is to be attached to a light bulb, effectively demonstrating the system's ability to generate electricity.
A video showing the power train for the scale model can be found here (YouTube link)
Wind Powered Model
The wind powered 1/4 scale model uses a parafoil attached to the arm via four rods. These rods are all attached to a bar that is free to rotate on the arm. The parafoil also has a stabilization rod through it to keep it at a consistent angle of attack to ensure good lift throughout its cycle, and to provide more generally stability in the air flow. When the fan is turned on, the parafoil lifts the arm until the parafoil goes out of the wind stream. The wind stream is cut off by a piece of foam on the stabilization structure. When it leaves the airflow, the parafoil drops, and the cycle begins again.
A video showing the scale model oscillating with the fan can be found here (YouTube link)
