> For the complete documentation index, see [llms.txt](https://rocketry.gitbook.io/public/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://rocketry.gitbook.io/public/previous-projects/ellie/physical-system.md).

# Physical System

Gasesous Oxygen - Liquid Ethanol (95%) Rocket Engine

<figure><img src="https://2333413738-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LB423_rlWTQK_KuQzK5%2Fuploads%2FWs6c31hysr8xVp3T5282%2Fphysicalsystem2.png?alt=media&amp;token=121a23b7-987e-4d22-8b8f-ebde168a1117" alt=""><figcaption><p>Piping &#x26; Instrumentation Diagram (P&#x26;ID) for ELLIE</p></figcaption></figure>

<figure><img src="https://2333413738-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-LB423_rlWTQK_KuQzK5%2Fuploads%2FWG5siV59XGqB0uqhDdaB%2Fphysicalsystem1.png?alt=media&amp;token=32372253-fc99-4a45-9570-74882554e1d2" alt=""><figcaption><p>Cross-sectional view of the ELLIE thrust chamber, injector, and load cells</p></figcaption></figure>

* Thruster:&#x20;
  * Radiatively Cooled (Heat Sink) Combustion Chamber / Nozzle
  * Injector: Coaxial Shear element mixes compressible GOX with ethanol. Dampens pressure instability through 30% Combustion Pressure element flow resistance
  * Thrust Measurement: (Target 30lb thrust)
    * Three S-type load cells, together, measure total thrust force
  * Pressure Measurement:&#x20;
    * Wheatsone Bridge Diaphram Pressure Transducers measure intense distributed forces
* Feed System:&#x20;
  * Energy Regulation:
    * Spring-Loaded Regulators and Stainless Steel Ball 2/3-way Valves.&#x20;
    * High-Pressure copper tubing, braided stainless steel flex hoses.