Using bendable cardboard solved the problem and provided us with a viable structure which we used to test several types of air foils and to develop a high efficiency, low speed, high lift wing section. Several of theses wing sections were joined together to make a viable flying model of a human powered plane. It consists of an intake horn with a 2 ft by 2 ft intake area, a 12 in by 12 in observation chamber and a matching exit horn. Preceding the intake section is a straightener section which eliminates air flow turbulence from the fans. The strength of the plexiglass along with its transparency, make observation of models from all angles possible, while maintaining a rigid shape.
Rigid walls prevent flexing under pressure from high speed air flow which can produce turbulence.
We are able to photograph our models through the chamber walls and roof with a video camera, a print camera and a digital camera. We will use our image processing skills to enhance the anticipated stream flow pictures. Hopefully, this will help our airfoil design capability. The assembly is opened, the insert put in place and the chamber put back together and the fan started. Darkening the surface of the insert cardboard increases the quality of our images.