Combustion Chamber

2025 | Liquid Engine 3 (LE3)

Combustion Chamber Component

Joining the liquid engine subteam within STAR, I specialized in manufacturing, primarily using the machine shop's lathe and mill for parts with critical dimensions and interconnected fits.

This role strongly improved my DFM and skills in creating practical drawings, building upon the concepts in classes of fits and tolerancing.

SKILLS

DFM

GD&T

Manufacturing

MACHINES

Mill

Lathe

TOOLS

CAD

The specific subassembly these parts belong to is the injector and combustion chamber, which work together to mix and ignite liquid oxygen and kerosene, generating high-temperature, high-pressure combustion gases that produce thrust.

Injector CAD Assembly

Highlights

Threaded Rods

Clamps combustion chamber together.

Threaded Rods
Injector Parts

Injector Assembly

Distributes fluids radially.

Reservoir

Structurally integrates all components and tubes.

Reservoir Manifold

Drawings & GD&T

Precision was paramount for the injector assembly. I utilized Geometric Dimensioning and Tolerancing (GD&T) to ensure the engine seals correctly under high pressure.

  • Concentricity (Single-Setup Machining): Maintained 0.005” Total Runout between the pintle bore and outer diameter by referencing all machined critical features with dial indicator.
  • Datums (Geometric Controls): Established the manifold mating face as Datum A to control the Perpendicularity (⊥ 0.002”) of the threaded rod pattern, ensuring uniform compression across the sealing face.
  • Fits & Sealing (O-Ring Glands): Machined dimensions to within +0.000/-0.002” to guarantee 20% volumetric squeeze on the O-rings, ensuring a leak-proof seal despite the thermal contractions.

Results: Hotfire Test Assembly

The manufactured components were integrated into the hotfire test stand shown below. The assembly features a load cell mounted inline with the thrust axis to directly measure engine performance.

Hotfire Test Assembly

This static fire setup validates the injector geometry and cooling efficiency before the final flight hardware is machined for the IREC 2026 competition.