The spreadsheet is located here: https://docs.google.com/spreadsheets/d/1JRF1jpii5KTwKIDkutjp5YCkuJp4Eh8oAxtDvMn6QBs/edit#gid=0
First: if you are about to add something to the spreadsheet ask the following question:
Am I a subsystem lead, team lead, Joel or do I have express permission from one of them to add information?
If no please don’t touch anything
Is it the time in a cycle to add information?
If not then don’t touch anything.
Simple steps to adding information:
Talk with your subsystem designers and make educated guesses at the values we are asking for: Min, expected, and max mass (in lbs), as well as CG (in inches) for each component. See below for more info on how to make these guesses.
Go to the sheets document and find the section of the rocket you are responsible for. There should not currently be any information in that box. If there is, ensure you are on the right sheet corresponding to the correct cycle.
Input data into all boxes you are responsible for. Boxes that need data are outlined in thick black. Input the method you came to this number by and your initials with the date in the box to the right of the data you just entered. The initials and date are important so that integration concerns can be addressed with the proper person.
If there is any additional detail you think would be useful to know enter it in a comment on the corresponding sheets cell. The more background info the better especially for new designs.
What does each data field mean?
Source:
Everything you enter into the spreadsheet should have a source. See this if you’re unsure of how to calculate center of gravity. Some examples of acceptable sources are:
Measured with scale.
Solidworks CG calculation
Guess based on no design work (initial rough estimates only, not ideal)
Hand calculation based on conceptual design
Hand calculation based on detailed design
Initials and Date:
Everything you enter into the spreadsheet should have a name and initials to ensure traceability. I better not have to tell you how to type your initials.
Mass: (Subcomponents):
Min: This is the minimum mass required if your design goes perfectly smoothly and no additional mass is required.
Expected: This is the current best guess at the mass you think you will need.
Max: This is the worst case maximum mass you think the system will require assuming things go pretty bad.
E.g. this may be the mass required if reverting to previous years design.
Note section values will be autofilled based on values from subcomponents after all data is entered
CG: (Subcomponents):
Expected: Each subcomponent should have an expected CG. This value should be distance in inches from the forward of the section (i.e., towards the nosecone) to the CG of the subcomponent.
Note we are assuming mass is axially symmetrical so this value should be distance in the Z axis in CAD ignoring if the part is offset of center.
This value will most likely be a fairly rough approximation unless a detailed CAD design is complete of both part and section and materials fully selected.
The sections are measured as followed
Recovery section begins at the top of the parachute bodytube
Payload Bay section begins at the top plane of bulkhead lower coupler
Feedsystem begins at the top of the flat surface of the fill bulkhead.
Engine bay begins at the top face of the injector bulkhead which is where the longerons get bolted
Length: (this will be filled out by integration people probs Roman):
Note that lengths have been changed from being entered by each system designer to being more of an open integration conversation between Roman and all relevant parties.
If you have any issues at all or need clarification on anything please let Joel or Roman know.