[roc-chat] Re: Dual Deployment advice
- From: Lakestake Rocketry <lakestake@xxxxxxxxx>
- To: roc-chat@xxxxxxxxxxxxx
- Date: Wed, 13 Jun 2012 12:34:46 -0700
Hi Bob,
Dave Flynn and I did vacuum testing of ejection charges a couple of years
back.
We found that both black powder and smokeless powders work best if properly
contained. In a five sided solid aluminum tube they produced fine grey ash
with a complete vigorous burn even under full vacuum.
BP when 'loosely' contained in a hard plastic tube still lit under vacuum,
but scattered much of the charge unburnt with a lot of black sticky
residue. Pyrodex powder did worse.
The take away is that smokeless powders are fine to use for rocketry and
leave less mess. Any ejection powder should be solidly contained for any
use to aid cleanup and for all use over 10000 feet.
The sixth side of the solid containment chamber used in our testing was 3
layers of good electrical tape. Fewer did not work consistently.
The match was placed on top of the powder nearest the open side of the
cannister and all remaining space in the ejection cannister was packed with
non-flammable wadding to keep the match in contact with the top face of the
charge.
Hope this old info helps some of our newcomers, if I've skimmed over
anything of interest ask away.
Matt
P.S. Allen, this message was typed on my Android phone with no spelling
assist/mangle by an annoyingly eager OS. ;)
On Jun 13, 2012 11:45 AM, "Michael Klett" <xsive.guy@xxxxxxxxx> wrote:
> And don't put 2 1/2 grains in a "small"ish rocket either. :-) Ground
> test with smaller values working your way up.
>
> Thanks,
> Mike
>
> On Wed, Jun 13, 2012 at 10:41 AM, Jack Garibaldi <jackgaribaldi@xxxxxxx>
> wrote:
> > I like the disposable ones whether you make them or buy them they are
> easy
> > quick and disposable, I sale the quickbusrt EZ-Cannisters the have a
> small
> > which holds up to 3 grams and they have a large which holds up to 12 gram
> > charges (Gugisburg Style)
> >
> > Jack G
> >
> > -----Original Message-----
> > From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:
> roc-chat-bounce@xxxxxxxxxxxxx]
> > On Behalf Of Bob Brown
> > Sent: Wednesday, June 13, 2012 10:10 AM
> > To: roc-chat@xxxxxxxxxxxxx
> > Subject: [roc-chat] Dual Deployment advice
> >
> > Even though I am level 3 and made dozens of launches over many years
> almost
> > all of my experience has been with Public Missiles that use piston
> > deployment. My avionics experience is also with the Public Missiles
> design
> > that includes their own BP holders. I am planning now to build a Madcow
> > Rocketry fiberglass kit and need some advice on the deployment. I have
> both
> > a Missile Works and Perfectflite computer than I can use but am not sure
> of
> > a design for holding and igniting the BP. I've seen online the Blastcap
> > http://www.blastcaprocketry.com/index.html and Pratt Hobbies ejection
> > canisters http://www.pratthobbies.com/ejection_canisters.htm Any advice
> > about these or other systems would be appreciated . Hope you all had some
> > successful launches at Roc Stock.
> >
> >
> > Bob Brown
> > http://us.imdb.com/name/nm0113141/
> > http://www.tripoli.org/ #9186-L3
> >
> >
> >
> > --
> > ROC-Chat mailing list
> > roc-chat@xxxxxxxxxxxxx
> > //www.freelists.org/list/roc-chat
> >
>
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