> > On Fri, 28 Nov 97 18:29:04 GMT, "Piers C. Structures"
> > >I have been wondering about what I can expect from a CATO, especially
> > >since I tend to take my 3yo daughter along to help out. The Estees
> > >launch system I have has only about 15ft of cable, which seems to me to
> > >be quite close if there is a chance that the engine will breach by the
> > >casing failing. How far back is safe for engines up to C6's? Should I
> > >try to erect some kind of barrier between us and the launcher?
> > An Estes motor that CATOs will almost always do so by blowing out one
> > end or the other, thus directing the force upward or downward. I
> > don't think I've ever personally seen one split the casing.
> It's the 'almost always' that slightly worries me. There is also, on the
> pad, the blast deflector that might turn any downward vertical component
> into a horizontal trajectory, although I guess after the nozzle is gone
> the pressure of the burning propellant will not be anything much
> (perhaps just a big flame?). I think it is probably wise for me to get
> her a pair of saftey glasses and perhaps a hard hat, no?
Getting your daughter in the habit of wearing safety glasses or goggles
is a very good idea -- in the shop, as well as on the range -- and even
a hard hat isn't completely out of line. Even if you don't have that 1
in a million severe CATO, an ejection failure could cause a lawn dart,
or you could forget the clay in the nose of a rocket that >really< needs
it, or a motor could eject.
> > In any case, 15' is plenty of distance for C motors.
> It seems quite close to me, for an engine that put's the little Tornado
> 1500ft into the air.
There's a great deal of difference between expending all the motor's
energy accelerating a stable rocket, and expending it in all directions
at random. Also, the case and the rocket are made of materials that
won't travel far after leaving an explosion -- even if the motor did go
up like a firecracker (or even if you put a black powder firecracker the
size of a motor into the mount) fif*** feet would be adequate
separation, though more might be desirable.
For that matter, if it makes you feel better, it's not hard to splice
some extra wire into the launch leads and make the distance 25 feet
instead of fif*** -- and 25 feet is more than twice as safe as fif***
in a fragmentation accident, because of the way drag deceleration
works. You'll be able to track the rocket more easily from little
further back, anyway...
There are times when even the Weaver of Skeins can make an awful tangle
of a perfectly simple tapestry. -- M. A. R. Barker, _The Man of Gold_
Donald Qualls, aka The Silent Observer NAR # 70141-SR Insured
Rocket Pages http://www.FoundCollection.com/
Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.