Justin Notes:

  • Mention materials in the slide so you have assumptions recorded 

  • Have a bolt review with one of the alumni 

  • Sizes are skeptical= 70 thou nozzle is skeptical, array of smaller openings 

  • Consider just going to crow island 

  • Graphine is pretty microscopic 

  • Endburning is not standard = use bates grain because it’s standard 

  • Some effects are size dependent= consider making the motors bigger, you would be closer to the result you’d want to see 

  • Characterization hardware overconstrained- we don’t know whats in compression and in tension

  • Base plate, make it thick and tap it

Cruz Notes:

 

  • Doing it in the blast chamber:

    • Eliminates trip, allows for smaller motors

    • Problem: Blast chamber is bad at clearing out smoke

    • Problems: super small (below ⅛”) exit diameters

    • Measure pressure using a transducer

    • Measure combustion temp using a thermal camera

  • End burner design:

    •  Way simpler for burn rate calcs

    • Exponential function of burn rate and burn rate coefficient

    • Easy to mix and cast in bulk with no mandrel

    • Can do in excess of 8 points

    • Challenge: Combustion is not in the whole tube, meaning a pressure transducer relief valve needs to be in the side

    • Fear of overpressurizing the motor

    • Tap for the ignition system as well

    • Convergent section only meaning we aren’t optimized for thrust (no data)

  • Hardware calculations:

    • Design for 3000 psi yield

    • Doing hand-calcs yields a mucho thick tube of 1.5” Id and 2” OD

    • No need for flathead countersink screws now using 10-32 socket heads

    • Throat sizing: smaller than ⅛ “ to choke flow, super sensitive

    • Going from 200-1200

    • Using openmotor, a diameter of 0.07” for angry goat causes a pressure build of up to 4000psi

  • Test stand design - Aimee

    • Separate the hardware into multiple levels of steel plates, fastened together with threaded steel rods (½”) 

    • Lip thickness based on doubling motor thickness?

    • Prevents heavy rotating because of the heavy rings keeping it in place.

    • Pros: Easy to interchange motors, durable

    • Cons: Lots of steel, concerns about it falling (tipping over). As long as it isn’t too asymmetric it’ll be fine

  • Questions: It doesn’t seem reasonable to have that small of a nozzle, consider a series of opens to accelerate your flow. - Andrew K

    • We may increase the size of our hardware or increase diameter for larger burn area - Justin

  • Question: A lot of changes not to go to crow is unnecessary. The weather is good now and there aren’t many cons - Sam A.

    • Graphite grains are larger, so drilling small holes in it may be impractical. -Andrew R.

    • Very nonstandard geometry, you’re introducing lots of complexities - Sam

    • This hardware wasn’t designed for the blast chamber, we could do some endburners in the blast chamber and do high pressure tests at crow island - Justin

  • Question: Some effects aren’t size-independent, you should test in a bigger motor. Do a traditional bates design. Also an endburner will burn very slow - Andrew R.

    • Make a 1000 psi motor at around an inch if you need to - Andrew

    • Endburners aren’t easier to calculate because of temperature nonuniformities. If you can’t simulate that you won’t get good results. - Sam A

  • Question: Get rid of these nuts? - AK

 

 

 

What needs to be in tension, what needs to be in compression?

 

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