Rocketry Safety

[Mark Hamilton]

Hi, Zia members,

We hit a spectator with a G-powered rocket today.

It missed being a tragedy by eight inches. The rocket came in ballistic
into the parking area, left a paint stripe on the person's coat from
shoulder to hem, tore the hem of his jacket, and thudded into the
ground, making a four inch deep hole. (A woman with him fell to the
ground, but I think she just jumped back after impact.)  I can't stress
enough; eight inches to one side and we would be talking catastrophic,
if not fatal, injuries.

I don't know if the spectators were watching the rocket come in or not.
I know I was not, because I was talking, prepping and too busy (and
dizzy) to look up.  (I was probably only four feet from the impact
point.) Tia and others shouted a warning, but it was probably a second
before the rocket hit. I can't speak to whether others were watching it
or not. We didn't do anything different that we usually do, and the
rocket was launched the appropriate distance away from the range head.

I think we may have become complacent when big rockets are being
launched, and the results today could have been much worse. We need to
remember; big rockets are dangerous. The chances of hitting someone are
very small, but the risks of doing so are incalculable. We *all* need to
pay more attention to big rockets when they are launched, and ensure
that the rocket is pointed downrange (away from the range head) when it
is launched. When spectators are present, we need to be sure that they
know they need to watch as well. This is probably the most serious
incident I've seem in 25+ years with Zia; we need to try to ensure that
there is not another one.

I hope everyone has a Merry Christmas, and a Happy New Year. See you all
next year.

Mark E. Hamilton
Zia Spacemodelers Vice President
NAR #48641 SR,

[Thomas Beach]

Mark is correct that we need to pay more attention to rockets being
launched.

A note about the rocket: The was prepped correctly, and this was not a
matter of the parachute getting stuck in the tube; the ejection cap of
the motor was still in place—the ejection charge did not fire.

It is important that we ALWAYS aim our rockets with the thought of
"Where is this going to hit if it comes in ballistic?"  And this can be
very tricky when the winds are very low (as they were today). If there
is substantial wind, the rocket will pretty reliably arc upwind, even if
it tips off of the launch rod direction by a few degrees, so the
trajectory is pretty predictable. But with low wind, the dispersion off
the rod can result in the rocket heading almost any direction due to a
few degrees of tip-off...so MORE rod angle than normal is needed in low
winds. I know that it is the tendency of rocketeers to want to avoid
launching far from vertical (since it means a longer walk to recover the
rocket), but we MUST remember to use sufficient downrange angle to be
safe. And we must remember to remind each other to do this.

I will be mentioning the need for more diligence in our next launch notice.

--Thomas Beach
  Zia Section Senior Advisor