Plumbing, or piping, refers to the system of pipe, tanks, and valves the form the feed system for the engine.

Test Center Plumbing Overview

Fuel and Oxidizer Tanks

We will have two storages tanks on the rocket, one for kerosene and one for liquid oxygen. Storage tanks for liquid at 300psi can be complex and heavy, but liquid oxygen creates an additional challenge. Liquid oxygen must be kept at a temperature of -183°C to maintain it in a liquid phase. At such low temperatures, materials can behave differently. For example, PTFE seals will become harder, and more brittle, and aluminum will shrink by about 0.1%. This may seem insignificant, but it must be taken into consideration.

To overcome these challenges, we have designed aluminum tanks with a unique end cap. The tank bodies are simply 4" diameter aluminum tube with a female NPTF thread. The end cap will have the matching NPTF thread to fit inside of the tank. NPTF is a standard outline in ANSI B1.20.3, and is very similar to the NPT thread. NPT stands for National Pipe Taper, and is a thread standard for pipe fittings. It is tapered to ensure a tight seal, but some sealant is still required (often PTFE tape, or plumber's tape). NPTF (National Pipe Taper Fuel) is a nearly identical standard, but with an interference fit. The internal threads are cut slightly smaller and deform when the male thread is inserted. This creates a much tighter seal and can be used without an additional sealant.

Liquid Oxygen Tank Cap, Bottom Liquid Oxygen Tank

© 2015 Let's Build Rockets Facebook YouTube GitHub