JB3-2102 Design, Analysis, and Test of a High-Powered Model Rocket-2 A Major Qualifying Project Report Submitted to the Faculty of the WORCESTER POLYTECHNIC INSTITUTE in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science in Aerospace Engineering by _________________ _________________ _________________ Julia Bigwood Robert Connor Colby Gilbert _________________ _________________ _________________ Caroline Kuhnle Alec Mitkov Nathaniel Rutkowski _________________ _________________ Christian M. Schrader James Ternent April 13th, 2021 Approved by: _______________________ John J. Blandino Professor, Aerospace Engineering Department Worcester Polytechnic Institute This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on the web without editorial or peer review. Abstract This paper describes the design, analysis, assembly, and test of a high-powered model rocket designed to use an actively controlled set of grid fins for stabilization, and a cold gas thruster for its terminal descent. The grid fins were modeled using SOLIDWORKS and 3D printed for subsystem level testing using an Arduino microcontroller. A mechanical separation system for the second stage was designed using linear actuators and 3D printed clasps. Aerodynamic loads on the vehicle airframe, grid fins, and stabilizing fins were evaluated using computational fluid dynamic (CFD) tools in Ansys Fluent. Results from the CFD analysis were used as inputs to a dynamical simulation of the vehicle trajectory and attitude, implemented in MATLAB. Ansys Workbench was used for structural analysis. An analysis of the composite motor was completed using Cantera and COMSOL to model the chemical equilibrium reaction and evaluate the temperature distribution in the motor during flight. These results were used to provide chamber conditions in a MATLAB model for ideal rocket performance. Finally, components for the cold gas descent propulsion system were identified and the required thrust and on-time for various landing velocities evaluated. Results are presented from these analyses as well as a description of prototype construction and testing completed at the subsystem level. “Certain materials are included under the fair use exemption of the U.S. Copyright Law and have been prepared according to the fair use guidelines and are restricted from further use." 1 Acknowledgements The MQP team wants to recognize and thank the individuals and groups listed below for their support and help over the course of the project. • Project Advisor Professor Blandino for his guidance and support over the course of the project • Professor Hera for training and helping the team with Ansys and Fluent • Alicea Hyland for helping and confirming the Fluent model for ascent was correct • Dr. Erica Stults and the WPI Rapid Prototyping lab for helping with 3D printing and design advice 2 Table of Contents Acknowledgements ............................................................................................................. 2 1 Introduction ................................................................................................................ 17 1.1 Literature Review ................................................................................................ 18 1.1.1 Airframe and Recovery System ..................................................................... 18 1.1.1.1 Airframe of a Model Rocket .................................................................. 18 1.1.1.2 Avionics Bay .......................................................................................... 20 1.1.1.3 Motor Bay .............................................................................................. 22 1.1.1.4 Nosecone ................................................................................................ 23 1.1.1.5 Recovery System .................................................................................... 25 1.1.2 Propulsion, Thermal, & Separation Systems ................................................. 31 1.1.2.1 Solid Rocket Motors............................................................................... 31 1.1.2.2 Staging .................................................................................................... 34 1.1.2.3 Ignition ................................................................................................... 37 1.1.2.4 Motor Mount .......................................................................................... 37 1.1.2.5 Mechanical Stage Separation ................................................................. 39 1.1.2.6 Nozzle Design ........................................................................................ 41 1.1.2.7 Cold Gas Thruster .................................................................................. 44 1.1.3 Flight Dynamics Analysis .............................................................................. 45 1.1.3.1 Flight Dynamics ..................................................................................... 45 1.1.3.2 Controls .................................................................................................. 47 1.1.3.3 Dynamical Simulation ............................................................................ 53 1.1.3.4 Aerodynamic Modeling.......................................................................... 54 1.2 Overall Project Goals .......................................................................................... 56 3 1.3 Project Design Requirements, Constraints, and Other Considerations ............... 58 1.4 Tasks and Timetable............................................................................................ 59 2 Airframe and Recovery System .................................................................................. 64 2.1 Methodology ....................................................................................................... 64 2.1.1 Airframe ......................................................................................................... 65 2.1.2 Grid Fins ........................................................................................................ 68 2.1.3 Flight Camera................................................................................................. 76 2.1.4 Nosecone ........................................................................................................ 78 2.2 Analysis ............................................................................................................... 79 2.2.1 Finite Element Analysis with Ansys Airframe Stress Distribution ............... 79 2.2.2 Computational Fluid Dynamics Analysis with Ansys ................................... 82 2.2.3 Airframe Stress Distribution (Analysis Task 1)............................................. 86 2.2.4 Grid Fin Aerodynamic Loads (ARS Analysis Task 2) .................................. 94 2.2.5 Grid Fin Stress Distribution (Analysis Task 3)............................................ 110 3 Propulsion, Thermal, and Separation Systems – Design and Analysis .................... 115 3.1 Methodology ..................................................................................................... 115 3.1.1 Engine Systems ............................................................................................ 116 3.1.2 Ignition System ............................................................................................ 116 3.1.3 Motor Performance Analysis (Analysis Task 1) .......................................... 117 3.1.4 Thermal Distribution Model (Analysis Task 2) ........................................... 119 3.1.5 Separation .................................................................................................... 125 3.1.6 Black Powder Charges ................................................................................. 126 3.1.7 Mechanical Stage Separation System (Analysis Task 3) ............................. 127 3.1.8 Cold Gas Thruster ........................................................................................ 132 3.2 Analysis ............................................................................................................. 133 4 3.2.1 Motor Performance Analysis (Analysis Task 1) Results ............................. 133 3.2.2 Thermal Model (Analysis Task 2) Results .................................................. 136 3.2.3 Mechanical Stage Separation Model (Analysis Task 3) Results ................. 139 3.2.4 Cold Gas Thruster Descent Model (Analysis Task 4) Results .................... 143 4 Flight Dynamics Analysis ........................................................................................ 148 4.1 Methodology ..................................................................................................... 148 4.1.1 Stability Fin Design ..................................................................................... 148 4.1.2 Avionics Implementation ............................................................................. 150 4.1.3 Avionics Bay ................................................................................................ 152 4.2 Analysis ............................................................................................................. 153 4.2.1 Analysis Task 1 (Vehicle Dynamics and Performance Model) ..................