General Info and data files for comparison

[benrussell11]

Hi Andrew,

I posted the following on the Rocketry Forum and have moved it to here. Hopefully that is ok.

I haven't used GitHub before, so bear with me. How do I set the issue type?

I've put together Zip file which contains my IREC team's characterization testing. A couple of notes:

• ProPEP 3 was used to determine propellant characterics - A&N etc.
• Their goal is a 98 mm 10 - 20 % N with a smoke grain.

The zip file contains the following:

• 1. *.txt - static test data. File name is the throat in 64's
• 2. *.bsx - Burnsim files - Propellant is 2019 IREC Blue
• 3. *.ric - openMotor files - Propellant is 2019 IREC Blue
• 4. 76mm Characterization Tests.xlsx - Test data. Average and Maximum Pressure calculated and burn time.
• 5. 98 2nd Static Test.bsx - Burnsim for next static test
• 6. 98 2nd Static Test.ric - openMotor for next static test
• 7. 98 2nd Static Test with smoke grain.bsx - Takes into account the 1" propellant delay grain
• 8. 98 2nd Static Test with smoke grain.ric - Takes into account the 1" propellant delay grain
• 9. 2019 IREC Test data.MTD2 - ProPEP3 - average pressure is used calculate A&N

General notes for the above

• For the static test burns, openMotor and Burnsim are close and compare well to the test data.
• However, they do differ in the total impulse and calculated thrust/force.
• Since I used average pressure to calculate A&N etc, Burnsim and openMotor max pressure matches the average pressure. Curious, do you use max or average pressure to calculate A&N?
• I believe this motor is a little on the erosive side.

IREC Test Data.zip

Ben

[reilleya]

Thanks for the data! You can assign labels to categorize issues. I labeled this one "data" to show that it contains test data so we can return to it as we add new features to make sure that the software still predicts your results correctly. I will dig into this within the next week or so to see if I can find anything new in the data, but it is good to hear that the program predicts the results well.

I typically use the average pressure during the steady state operation of the motor, so really just the average with the startup and shutdown transients chopped off. It is sometimes hard to draw that line if startup or shutdown aren't aggressive, but it makes sense to me to use the average pressure because we only have access to average burn rate. We're excited to get as much data as we can for erosive motors! Please post your data from the full scale motor once you have it. With enough data, we should be able to build a good enough model for erosivity that users can design around it and not have to risk their hardware.