[BProckets] Cluster ejection

[mrgizmo]

I never thought of that, that would not be a nice sight to see my recent
scatch build in flames. What are shear pins and what do they accomplish?

Thanks
Mike


----- Original Message ----- 
From: "Mike Harris" <mikeharris at privatedata.com>
To: "Black Powder rockets discussion list" <bprockets at amateurrocketry.com>
Sent: Tuesday, March 01, 2005 6:15 PM
Subject: Re: [BProckets] Cluster ejection


> No it is not a great idea. Maybe now your motor that didn't start now
fires
> up from the top from the match at the same time the chute ejects thus
> turning it into an interesting pyro sky work that hopefully at best
results
> then in a flame flare (burning rocket) coming down under chute.
>
> Most likely you won't be *that consistent* with your ejection delays and
> that the bonus charges won't blow anything up. Any charges post fact are
> not relevant. So use shear pins, not friction fit, for your nose cone, and
> have a long enough shock cord to dissipate even a triple ejection
> separation, and you should be fine.
>
> Either that or, as most with EX do, use electronics for any ex motor.
Along
> those lines, the magnetic apogee kits are cheap, effective, and cool.
>
> Sure it's cool to do *everything* including ejection delays, but it's
> another problem to learn to do right and is perhaps the most critical
short
> of not cato'ing your motors, so why not ensure you get your rocket back
for
> it's next flight.
>
> regards, Mike
>
> At 02:03 PM 2/28/2005, mrgizmo wrote:
> >That is a great idea about using 1 chage that is quickmatched to all
theee
> >motors, I never thought of that, its likely what I will use.
> >
> >----- Original Message -----
> >From: "Dan Durachko" <DanDurachko at psu.edu>
> >To: "'Black Powder rockets discussion list'"
<bprockets at amateurrocketry.com>
> >Sent: Monday, February 28, 2005 12:27 PM
> >Subject: RE: [BProckets] Cluster ejection
> >
> >
> > > I imagine the engine loading procedure and mount design would preclude
> >such
> > > a measure but could you cross-match (w/quickmatch) all three of the
> >ejection
> > > charges to synchronize them and ensure ejection?  Also, I imagine
there's
> > > enough slop in powder amounts for efficient ejection that you could
load
> > > each of the three engines in the cluster with 1/2 the amount needed
for
> > > positive ejection and even if all three fired you still wouldn't cause
any
> > > damage?  Let me know how things work out and how you did it.
> > >
> > >
> > > Good point, I guess the dilemma isuse one ejection charge and if that
> >motor
> > > dosnt ignite the fiberglass nosecone turns into a pretty dangerous
> > > projectile. But if I use 3 unsyncronised ejection charges the result
could
> > > burn up the chute(s).
> > >
> > > > >I am currently finishing up a 1/3 scale Harpoon AGM-84, which will
fly
> >on
> > > a
> > > > >cluster of 3 G-75's I was just wondering if I should just set up
one of
> > > the
> > > > >motors with an ejection charge or all three?
> > > >
> > > > I've wondered about this too.  I guess it kind of boils down to
whether
> > > you
> > > > feel you can reliably get ignition of all 3 engines in the cluster.
How
> > > bad
> > > > might 3 synchronized (or unsynchronized) ejection charges be
anyway???
> > >
> > >
> > >
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