Propellant Feed System

Propellant Feed System Layout
Goal: minimize pressure losses tradeoff diameter and routing of lines.
Size of lines - diameters. To minimize pressure loss large size is good. Tradeoff - the 
larger the lines the more difficult routing becomes and the haavier they become.
Require ñ3 degrees to Gimbal - all ducts must flex (bellows/joints) 

Length short as possible to minimize pressure loss.

Want a straight run of duct into pump to minimize turbulence.

With cryogenics - heat in propellant ducts is a difficult issue
Foam insulation to keep cold
Flexure joints are not insulated.

Propellant Level Indication System (PLIS) - this system is used to burn down oxidizer and 
fuel simultaneously - decrease evenly.

Goal is to run out of O2 first.
It pushes the limits to deliver a heavy payload or to place in a high orbit (100 miles to 
24,000 mile high orbits are used). 

H2 lines - crack tube - self-healing. the crack doesn't progress rapidly. 

Ducts
Vehicle effects - flow acceleration 3 1/2 inch propellant ducts. Fuel line 15', Ox line 3'
Propellants are at rest when flow starts, velocity increases. Need additional pressure.