[NRVR-Members] Anyone Ever Use RCS Motors?

Thomas Tweeks Weeks tom at theweeks.org
Sat Jun 2 23:46:16 CDT 2018

Thanks for the great reply Chris..

I know you've gone all hard core, home-brew lathing etc.. I don't think we're there.. Especially since the majority of our launches here (with our 10k waiver that we rarely break 8k on) and while we have flown some 98mm here.. we mainly fly on 75mm and lower (a lot of 54.. and a ton of 38mm).

Yeah.. a couple NRVR have members have mixed before.. and we're to that point that a few of us are starting to sniff at doing it.  You make a great point about all choosing to go with the approximate same research motor hardware so we can settle on standard/same liners, grain dimensions, molds, share parts, etc.  The VT student group just got a static test rig too, and we're getting a nice (long distance) wireless LC system.. so we're in a good place to start playing around with mixing and doing motor tests.

Tell me.. do you have a dedicated test casing with tapped pressure transducers?  Kind of.. one for testing and one for flying? (just curious)

Sounds like we should discuss some of these points you bring up.. just to get the most out of it "as a club".

If anyone else has any thoughts.. please chime in.  I'm not so much leading the discussion as much as I am just poking people to get a sense of people's thoughts who are interested in it.


On Saturday, June 2, 2018 6:15pm, "Maier.chris" <maier.chris at gmail.com> said:

> _______________________________________________
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> http://server2.nrvr.org/mailman/listinfo/nrvr-membersTWeeks,
> I think the Aerotech hardware & reloads have all been tested and are NAR approved
> true commercial reloads.  The RCS components at one point may or may not have been
> as completely tested as the Aerotech stuff and was therefore
> “experimental”.  Not sure if that’s still true these days.
> Most experimental motors work just fine in the Aerotech or RCS hardware that is
> 75/76 mm and smaller - as long as you get a casting set & liner that fit the
> hardware properly....  At 98mm and above, I buy quality aluminum tube and have it
> machined myself.  I have a lathe that I can build closures and graphite nozzles
> on.  This typically leaves me with a tube that isn’t anodized, which is
> actually sub optimal - I need to set up an anodizing rig.  Building your own tubes
> isn’t “better”, I do it simply because it can be more cost
> effective since I’m not getting “DOM” material (drawn over
> mandrel). DOM is horridly expensive and there are minimum quantities that no
> single user would be able to afford or use if it’s not a stocked dimension. 
> If a supplier has some left over DOM material, or it’s a dimension they
> stock, it’s 1.5x or more the price of plain tube.  But plain tube
> isn’t as round and wall thickness varies significantly more than DOM.  I was
> REALLY bummed out when tru-core quit making cases.  Loki is a great alternative,
> just slightly more expensive.
> Rocket motors, much like the camera “Cannon vs Nikon” debate (non
> professional photography) really boils down to - what do your friends and family
> have so you can borrow things.  Rocket motor hardware, IMHO, works similarly - buy
> what the majority of your friends have so you can borrow, trade, and sell parts
> and reloads with each other.  Or if you are doing Ex motor casting with your
> friends, you don’t have to worry about confusing liners and casting tubes
> that are incompatible with one another (Loki vs gorilla vs Aerotech etc).  We have
> mixing parties here, and four or five guys will show up.  So not having to run
> specific batches and not have to pay super close attention to the liners etc is
> beneficial to us.
> Last but not least, if you are doing Ex motor mixing, just like your ejection
> charges, you should be testing your motors - at least a representative diameter in
> order to validate your pressure assumptions, burn rates, and all that Jazz.  Only
> then will you know if you actually have a “super aggressive” motor and
> then you can make alternative hardware selections if necessary.
> Chris
>> On Jun 2, 2018, at 16:28, Thomas Tweeks Weeks <tom at theweeks.org> wrote:
>> Yeah Bob.. that's what's confusing. I assumed if RCS was there for the research
>> motor community, that their casings would necessarily have the thicker/heavier
>> casing walls to handle some of the challenges of research loads... no? All I see
>> is fiberlgass casings, so I'm not guessing you get to reuse all the parts (just
>> the closures and the nozzles a few rimes?).
>> Is Loki and others recommended over RCS hardware for fully reusable "aggressive"
>> research/DIY hardware?
>> They seem to be really well equipped.. and sell everything that's needed...
>> Tweeks
>> On Saturday, June 2, 2018 7:33am, "Bob Schoner" <bob.schoner at gmail.com> said:
>> Yes Gary Rosenfield started and is the owner or Aerotech. He also started
>> Rosenfield consulting services (RCS) maybe 10 years ago to service the research
>> community.
>> If you’ve flown Aerotech motors, you have used RCS stuff. I think the
>> disclaimer is meant to say that the commercial hardware does not have the wall
>> thickness needed if you are making very aggressive propellants. It seems to hold
>> up just fine with aggressive AT reloads, but generally people doing research use
>> thicker walled cases like Loki, AMW, and Mostly Missiles. In my experience this
>> is what I’ve seen.
>> Bob
>>> On Sat, Jun 2, 2018 at 7:15 AM David Bloom <dwskb at att.net> wrote:
>>> Yes.  Our emails crossed.
>>> --------------------------------------------
>>> On Sat, 6/2/18, Adrien Drouault <adrien.drouault at gmail.com> wrote:
>>>  Subject: Re: [NRVR-Members] Anyone Ever Use RCS Motors?
>>>  To: "NRV Rocketry Members" <nrvr-members at server2.nrvr.org>
>>>  Date: Saturday, June 2, 2018, 2:33 AM
>>>  Correct me
>>>  if I'm wrong, but isn't Aerotech the
>>>  "hobby" arm of RCS?
>>>  On Fri, Jun 1, 2018 at
>>>  11:35 PM, Thomas Tweeks Weeks <tom at theweeks.org>
>>>  wrote:
>>>  Just
>>>  curious if anyone's ever used these motors?
>>>  https://www.rocketmotorparts.
>>>  com/
>>>  Chris
>>>  Maier?
>>>  Very
>>>  interesting stuff..  Looks like all research and DIY based
>>>  stuff.
>>>  Tweeks
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>>>  sit altum viditar.
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