Sean H. Breheny wrote:
> At 01:39 AM 10/14/99 -0500, you wrote:
> <snipped>
> >I was at the meet here in muncie when AFAIK the first injury directly
> >related to model rocketry occurred. A fellow was prepping his bird, and had
> >his head over/inside the body, when the computer-controlled ejection malfed,
> >blowing at least a gram of FFFF powder in his face.  We had an optometrist
> >on him in seconds (damn good luck!) and an ambulance rolling in a few more
> >seconds. His sunglasses saved his eyes.
>
> I don't know what FFFF powder is,but this definately doesn't sound good!
> I have never gotten into serious rockets,but I'd like to. (non-sequitor to
> previous comment!)

FFFF is Black Powder, F is cannon grain (coarse), FF Rifle grade, FFF
Pistol grade (fairly fine), FFFF is "primer pan" (for flintlocks)
typically.  It burns really fast (appears to "explode", darn near!),
that was a pretty serious accident - GLAD it turned out so well.  (I've
always seen these as FFG, FFFG, locally, IIRC.)

> >This computer controlled recovery system is commonly used, but apparently
> >his safety interlocks weren't functional, and it blew.  They sense by
> >barometric sensor, and it may be that a drop of sweat or conductive debris
> >hit the controller board.

Can you say "Conformal Coating", chorused, folks?  <G>  Saving weight's
one thing, even a tissue paper thin conformal cover on that PCB would
have prevented this, probably.  Or powering off the ignition battery
before sticking his head in the unit.  (I've thought of making such a
system, with a "G" sensor like a sprung small weight being used to arm
the system, no power for ignition until (Switched on) && (Parachute is
present above sensor) && (waitfor: (G force > 2G), present for 1/4
second or more), or something like that.  Used to be heavily into model
rockets, no time lately, darnit!  Safety in design issue here, far as
I'm concerned - Anything that actuates something that can hurt/damage
someone, or any device designed to prevent injury, needs to be
well-thought-out with regards to not CAUSING injury...

  Mark