Design and Performance of Modular 3-D Printed Solid-Propellant Rocket Airframes

Solid-propellant rockets are used for many applications, including military technology, scientific research, entertainment, and aerospace education. This study explores a novel method for design modularization of the rocket airframes, utilizing Additive Manufacturing (AM) technology.

The new method replaces the use of standard part subsystems with complex multi-function parts to improve customization, design flexibility, performance, and reliability. To test the effectiveness of the process, two experiments were performed on several unique designs:

• ANSYS CFX® simulation to measure the drag coefficients, the pressure fields, and the streamlines during representative flights and fabrication and launch of the developed designs to test their flight performance and consistency.
• Altitude and 3-axis stability was measured during the eight flights via an onboard instrument package.

Data from both experiments demonstrated that the designs were effective, but varied widely in their performance; the sources of the performance differences and errors were documented and analyzed.

The modularization process reduced the number of parts dramatically, while retaining good performance and reliability. The specific benefits and caveats of using extrusion-based 3D Printing to produce airframe components are also demonstrated:

• 3D printing, particularly extrusion-based processes, is an excellent method for producing the complex multi-feature parts needed for optimized airframes.
• The print lines on 3D printed parts seemed to provide an advantage, not a disadvantage, to the rockets as it reduced the drag coefficient of the nose cone.

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