P18102: RIT Launch Initiative Hybrid Rocket
/public/Testing/Test Stand/

Test Stand

Table of Contents

Background

This test stand is designed to be installed into the on-campus bunker where we will be conducting our full-scale static test fires as well as other large subsystem tests. It is designed to withstand the 1,300 lbf thrust of our rocket and is currently limited by the capacity of our load cell, which is 2,000 lbf (overload limit of 3,000 lbf). This should be sufficient to withstand the force of future rockets designed and built by RIT students and associated clubs. If a larger or smaller capacity is required, a simple replacement of the load cell is all that is necessary.

Test Stand Assembly

A near-current representation of the assembly is shown below. Included, is a sensor attachment plan to show where we will be mounting various sensors when completing the static test fire.

Since our final tank design is still in question due to lead times, the tank mounting structure is not featured in -depth on this page. The tank mounting structure shown below is only a sample design, and represents the vertical orientation of the oxidizer tank.

Current CAD Model

public/Testing/Test Stand/Images/TestStandWithSensors.png

public/Testing/Test Stand/Images/ts1.PNGpublic/Testing/Test Stand/Images/ts2.PNG

Force Plate Assembly

The force plate will mount to the aluminum I-beam structures that we currently have on hand. Its role is to withstand the thrust forces of the rocket engine with a sufficient factor of safety. Some of the analysis on this component is summarized below in the Analysis Summary section.

The load cell mounting to the rocket chamber itself is still being designed. Once the injector assembly is complete, we can then design an interface that will butt-up against the external face of the injector plate.

Current CAD Model

public/Testing/Test Stand/Images/Force Plate CAD 1.PNGpublic/Testing/Test Stand/Images/Force Plate CAD 2.PNG

public/Testing/Test Stand/Images/Force Plate CAD 3.PNG

FEA Results

public/Testing/Test Stand/Images/Force Plate FEA 1.PNG

public/Testing/Test Stand/Images/Force Plate FEA 2.PNG

Motor Mount Assembly

The motor mount assembly consists of two identical aluminum structures with three ball-transfers on each. These ball transfers are equally spaced 120 degrees from each other and will allow the engine to only move in the axial direction against the load cell.

The 3/4" aluminum plates will be water-jetted and are designed to be two separate pieces: a top and a bottom. Originally, the chamber could be slid into the series of mounts, but now with the large flanges on both ends, we cannot do this. Instead, we will place the chamber on the bottom mount and ball transfers, and then bolt the top mount to the bottom.

The selected ball transfers were chosen for their capacity as well as their capability to work at any angle. They are rated at 110 lb each, so having four ball transfers to support the weight of the chamber will be sufficient.

Stud-Mount Ball Transfer

Current CAD Model

public/Testing/Test Stand/Images/Motor Mount CAD 1.PNG

public/Testing/Test Stand/Images/Motor Mount CAD 2.PNG

Analysis Summary

public/Testing/Test Stand/Images/TS-FoS.png

Additional Resources

http://aeroconsystems.com/cart/test-stand-pictorial