Test Stand for Rocket Combustion Chamber

September 2021
JHU AstroJays Rocketry Team

Objectives:

  • Design and build a test stand for the team's hybrid rocket engine, BJ01. The rocket engine is about 6 feet long and can theoretically generate 825 lb of thrust and 9100lbf-s of total impulse.
  • During a hotfire test, the rocket engine is fired while secured on the stand. Measurements such as chamber temperature, interior pressure, and the time vs. force curves are made.
  • Therefore, the design needs to withstand high shear forces and possibilities of structural deformations.
  • To improve structural integrity, we decided to place 4 sliding carriages under the chamber stand and the base. This allows the combustion chamber to slide backward slightly during firing. However, several important components are manufactured in either imperial or metric units. Thus, multiple plates were designed to mate the components across measurement systems.

    • Skills Applied:

  • Mechanical design, SOLIDWORKS parts and assembly
  • The ANSI Engineering Drawing standard

    • Comments:

  • I applied CAD and design knowledge from my first-year Mechanical Engineering courses. I also received a lot of help from upperclassmen and gained valuable experience in engineering design.
  • I created all the CAD files, drawings, and bill of materials in SOLIDWORKS. I was also in charge of working with the team treasurer on ordering components.
  • The actual thrust stand assembly was finished in Spring 2022, thanks to many teammates who spent many hours manufacturing.
  • Learn more about AstroJays

    • The clamp assemblies (Image from Rishi Bachani).

    Scroll sideways or click on the scroll bar below to view more images:

    SOLIDWORKS assembly of the thrust stand.

    The load cell interface.

    One of the two clamp sections.

    Back view of the thrust stand CAD model.

    Some of the componenets created or imported from the McMaster Carr website.

    Engineering drawing of a custom bracked part.

    Engineering drawing of the load cell plate.

    The Excel sheet BOM shared with my teammates.

    The CAD model and assembly drawing.

    Manufacturing progress 01.

    Manufacturing progress 02.