Solidworks model of the final design
At the end of first year at Queen’s University, all engineering students work on a group design project. Our team decided to take on the Queen’s Rocket Engineering Team as clients. They needed a test apparatus to allow them to test their prototype rocket motors. The primary challenge of designing a test stand for a rocket motor is constraining the motor while still allowing a load cell to be actuated. Our team came up with many possible solutions using linear bearings, 4-bar linkages, and multiple loadcells however these were all more complex than we wanted especially as cost is a significant constraint for student teams. The design we decided to pursue was based on a single pivot to guide the motor.
Our design works by fixing the motor vertically so the motor thrust pushes the structure into the ground. The motor is constrained using a simple swing arm that pivots on two bushings. Thrust is measured with a load cell between the swing arm and the base. Most of the structure is made of standard HSS stock which helps with cost. To allow the test stand to be transported, the can legs can unbolt and the swing arm can be removed. We were able to make the design adaptable to other motor diameters and lengths by allowing the mounting brackets to be removed and replaced. Since this was a first-year project, we did not have the opportunity to build or test the design. Despite that, we designed a well-thought-out system that achieves all the design goals excellently.