Please review the HEI Information page to get a general overview.
For staged rockets, the second stage has to be ignited near Vacuum space. We need a system that can raise the pressure in the chamber while increasing the temperature to reach combustion conditions.
With respect to the HEI used in the staging demonstrator, we increased the wall thickness and added a fillet between the base and the wall.
To calculate the MoS we use an ID of 1.375 in, an OD of 1.842 in, and the maximum pressure of the Sustainer with 826 psi.
6061-T6 Aluminum has a yield stress of 40000 psi.
Thus, the margin of safety is much more than the required minimum of one, which makes us confident that the wall will not yield.
Nevertheless, we would not decrease the wall thickness since we want to avoid radial tore of the bolts.
After finding that the previous O-Ring Configuration had potentially dangerous attributes according to https://www.applerubber.com/oring-gland-calculator/#medium-search-field. I changed the O-rings to yield safe values and uploaded the changes to the repository. I changed the 229 and 228 O-Rings to 230 and 229 respectively, then the 121 and 122 O-Rings to 122 and 123. Below are the images of the O-Rings and the values in the calculator.
O-Rings 1,2:
O-Ring 3: (Best stretch Arrangement I was able to produce without changing the Forward closure groove diameter (Am I allowed to?)
O-Ring 4:
O-Ring 5:
No Change, show open motor curve and talk about funny canted nozzles
Phenolic for forward closure.SLDDRW