criticalvector
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I'm trying to find one and am having trouble. I want to test out what apogee it would hit if just the booster (no dart) was launched from 10k feet AGL.
I'm trying to find one and am having trouble. I want to test out what apogee it would hit if just the booster (no dart) was launched from 10k feet AGL.
My guess is though that you weren't using 10 micron AP in a garage with a bread mixer. From everything that I know about any ultra fine particle, special care and handling is required. Everyone I've talked to that used ultra-fine AP did so remotely. But obviously I don't have real-world experience making commercial motors. I'd be interested in hearing how you handled such small particle sizes in processing.Made a few hundred of them.
Not scary at all.
Good info, thanks for that. So hammer mill as in smashing it? I know folks who ball mill AP but I've not heard of hammer milling it. I suppose then it would have to be sieved to separate out the right sized particles (same as with ball milling)? Not that I am planning on trying it anytime soon but still I've always been a big fan of the Loki Dart and our very first BALLS project was a boosted dart. The performance of the Super Loki motor never fails to amaze me, it was just a beast for its size.10 micron isn't very fine in commercial world, 2 micron is! Essentially everything we made that used AP had 5-15 micron depending on burn rate required.
The AP in the Loki series is hammer mill ground, Mikropulverizer, stored in oven at 140f to keep dry and used within 48 hours. Other than dust issue not a problem to work with. Always wear your respirator.
M
Here you go. A quick .eng file based on the report on NTRS
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680026183.pdf
For those interested, it's a 102mm (4") motor classified roughly as a 38000O18000. Sounds wicked fun. ;-)
Make sure also that the thrust curve is a sea level thrust curve. RASAero II assumes the data in the rasp.eng motor file is a sea level thrust curve.
Wow, I looked at the Mikropulverizer website. Very interesting machine, but it does not look inexpensive. I had not idea something like that even existed. This has been a great thread, learn more new stuff all the time.No need to screen, the way the Mikropulverizer works it acts like a centrifugal separator and the larger particles keep going around until broken up. For BIG motors it’s the way to go, ball milling takes too many batches and time.
Here's some additional data on the SLD. I have a manual that details the actual formula, but I won't post it here due to the prohibition on posting that type of material outside of the research forum. But maybe Mark can explain the numbers listed for the AP particle sizes? I don't understand the distribution range at all. TIA.
The screen shots are from the PDF at:
https://apps.dtic.mil/dtic/tr/fulltext/u2/750796.pdf
Make sure also that the thrust curve is a sea level thrust curve. RASAero II assumes the data in the rasp.eng motor file is a sea level thrust curve.
So, can you explain your milling process in more detail? (Maybe start a new thread rather than derail this one.) I ask because I have a large amount of 400AP that I would love to turn into either 90 or 200.A very important thing to consider in this thread.....While everybody in the hobby are concerned about using spherical particles for easier processing, milled particles give higher burn rates and better mechanical properties for high g applications. That's the reason I've always milled.
So, can you explain your milling process in more detail? (Maybe start a new thread rather than derail this one.) I ask because I have a large amount of 400AP that I would love to turn into either 90 or 200.
I am interested in the process Mike uses for milling his AP. For example, until this thread I had never heard of a Mikropulverizer machine, which obviously is an ideal solution. But it's likely beyond my budget.
That's exactly what I was looking for. I'm well familiar with Dillon gear so I can see how it is better than other mills. Obviously it will take some experimenting and I need to buy some sieves, but it gives me a good starting point.I use this with ceramic media: https://www.dillonprecision.com/dillon-s-cv-2001-vibratory-case-cleaner_8_8_23658.html Don't waste your time with other inexpensive vibratory mills like the ones they sell at Harbor Freight. I burned up a couple of those and the plastic housing disintegrated on one.
The key is to not necessarily go for a set particle distribution by screening and over analyzing, but instead, be consistent every time about how much you load the mill with and how long you run it for. For this, I just measure the same amount by volume, and then I have the mill on a digital timer. This ensures it will be the same, every time. That's the key. Good luck!
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