Mosquito: Launch/Find/Relaunch world record = 17 ????

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Prmafro » Fri, 14 Nov 1997 04:00:00



I had a Mosquito that had a too small body tube.  I had to bend a few rules and
 alter the case of the motor(for shame!) to get it to fit.  We had several
 successful launches.  Finally, one day, it went, we heard the ejection charge,
 recovered the enging, but never saw the rocket again.
Best guess?  I think the engine was too snug and it turned into confetti.
A sad day.  It was the first and only time I had ever lost rocket.  I had some
 destroyed during recovery, but they had all been recovered untill that point.

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by CPINE5 » Sat, 29 Nov 1997 04:00:00


Quote:
>I had a Mosquito that had a too small body tube.  I had to bend a few rules
>and
> alter the case of the motor(for shame!) to get it to fit.  We had several
> successful launches.  Finally, one day, it went, we heard the ejection
>charge,
> recovered the enging, but never saw the rocket again.
>Best guess?  I think the engine was too snug and it turned into confetti.
>A sad day.  It was the first and only time I had ever lost rocket.  I had
>some
> destroyed during recovery, but they had all been recovered untill that
>point.

 I got one last week as a kinda fun thing for my 4 yr old son and we painted it
white! Not good.. got 2 flights out of it and it was gone? Never seen it come
down.. it did go very high   though... :)

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Piers C. Structure » Sat, 29 Nov 1997 04:00:00




Quote:
>  I got one last week as a kinda fun thing for my 4 yr old son and we painted it
> white! Not good.. got 2 flights out of it and it was gone? Never seen it come
> down.. it did go very high   though... :)

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?

--
Suck The Goat

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Me » Sat, 29 Nov 1997 04:00:00


When they CATO, and it's not THAT often, they tend to vent upwards through the
rocket in the case of blowby, or straight down into the ground in the case of a
nozzle blowout. I have never seen one "explode" as in ***ly breaching the
casing sideways like a firecracker. Indeed this is a major safety distinction
from fireworks! Maybe others have seen casing ruptures, I have not. So with all
the material going either up into the air or down into ground/pad, I'd say it is
pretty darn safe.

Remember, the hobby would not be allow over here in the United Litigious States
of America if CATOs were often and dangerous.

IMHO of course... YMMV, VWP.

Quote:

> 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?

> --
> Suck The Goat

--
This message has been packed using modern automated machinery. Packed
by weight not volume, some settling of contents may have occurred during
shipment. "Trust but verify" - Ronald W. Regan on assembling a RMS.


NAR: 70988 Level I   Member: ROC and SCRA      TRA: 5678      IAR# 43

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Alan W. Holm » Sat, 29 Nov 1997 04:00:00


On Fri, 28 Nov 97 18:29:04 GMT, "Piers C. Structures"

Quote:

>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.

In any case, 15' is plenty of distance for C motors.

Alan Holmes

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Mark Bakaric » Sat, 29 Nov 1997 04:00:00


Quote:

> 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?

If you are worried, a good pair of safety glasses for
junior would be my choice. I've been launching rockets
with my daughters for years (they're now 8 & 11).
In my experience CATOs are rare and casing breeches
are rarer still. In the last three years, I've attended
approximately 350 launches. There were three CATOs as
described below:

1. Forward seal failure on 1/2A motor, ejecting burning
   propellant up through the rocket. No damage to rocket.

2. Forward seal failure on C motor, ejecting burning
   propellant up through the rocket. Parachute and shock
   cord were destroyed.

3. Casing breech on C motor, splitting body tube. Rocket
   was destroyed.

Items 2 & 3 above involved motors from the same package
and had been in storage for 2-3 years. These were owned
by someone else and I suspect had experienced temperature
cycling. Buy fresh motors from a good dealer, and store
them at room temperature. Check the date code before
using them. Yes, there is a risk, and you have to make
the choice, but for millions of kids it's quite safe.

--
Regards,
--------
Mark Bakarich,  Engineer, YABAR, Tucson.

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by BULLPU » Sun, 30 Nov 1997 04:00:00


Quote:
> I have never seen one "explode" as in ***ly breaching the
>casing sideways like a firecracker.

guess you never fired an estes E15.  KABOOM  8^(

Bill Rossi  TRA# 3915  Level 2
President   METRA  TRA#94
Metropolitan Rocketry Association
Tripoli North Jersey
Web page   http://www.FoundCollection.com/
I'm just an anolog man in a digital world

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Rob Zingarell » Sun, 30 Nov 1997 04:00:00


Quote:

> On Fri, 28 Nov 97 18:29:04 GMT, "Piers C. Structures"
[snip]
> >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.

I've seen one casing-side cato, 20 years ago.  It was more of a burn-through
than an explosion however: my Vulcan left the pad normally, then at 20'
altitude made a near-90 degree turn, ended up 30 yards downrange with a slit
burned through the side.  Centuri C6-5, IIRC.

About barriers, not needed.  "Firecracker" catos are nearly non-existant
(anyone ever seen one?), as Alan pointed out.  End cap blow-outs are pretty
benign, though destructive to the rocket itself.  In case of nozzle blow-outs
though, I use a 4" galvanized steel drain spout elbow, which directs the clay
fragments away from everyone.  The one time this has happened recently, it
really got my 4-yo daughter's attention!

--
-Rob Zingarelli
  NAR 62460
  Trolls depend on honest net-er's replies for food.  Let 'em starve.
  Spam's started heating up, so yank "boing." from the above address.

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Piers C. Structure » Sun, 30 Nov 1997 04:00:00




Quote:
> 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?

Quote:
> 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.

--
Suck The Goat

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by Balthez » Mon, 01 Dec 1997 04:00:00


TankCdr Wrote:

Quote:
>I _have_ seen a casing breech CATO.  My son as given an old, improperly
>stored
>Estes D12-3 which ruptured just as the rocket was leaving the launch rail.

Ear;ier this year, I saw an AT G80 cato upon ignition in a beautiful Boyce
large Mercury Redstone, the Redstone's second flight attempt. It blew the tail
end to bits. The owner said it was pretty much a total loss.

--

Bruce Kirchner
TRA L1 #5888     NAR #69850
Michigan Team 1 HUVARS
Visit My Rocketry Home Page - http://members.aol.com/balthezar/index.html

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by WillCarn » Mon, 01 Dec 1997 04:00:00


Quote:
> I have never seen one "explode" as in ***ly breaching the
>casing sideways

I have seen several at our club launches in Champaign IL.
They went right out the side.
**************************************************

It's not what you got, it's what you do with it.

Try helping other's instead of hurting them.

Instead of fighting over that inch of ground
lets move out into space and live in peace.

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by The Silent Observe » Mon, 01 Dec 1997 04:00:00


Quote:



> >  I got one last week as a kinda fun thing for my 4 yr old son and we painted it
> > white! Not good.. got 2 flights out of it and it was gone? Never seen it come
> > down.. it did go very high   though... :)

> 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?

I've been back in the hobby about two years, now.  In that time, I've
burned close to 200 Estes and Quest motors, and around a dozen
composites (maybe a few more), and I've had four CATOs -- one ejection
at burnout with a 1/2A6-2, another such with a 1/2A3-2T; one complete
case-cleaner with a D12-7, and a forward bulkhead failure with an
Econojet F20-7.

In none of these cases would anyone even ten feet from the model have
been at risk (providing they were able to dodge the smoking delay charge
as it ejected from the Ecatojet -- it landed about 10 feet from the
pad).

In the same time, I've probably seen around 30 CATOs of other people's
rockets; the only one of those that would have presented a hazard at 15
feet distance was a 38mm High Power rocket that chuffed hard enough to
pop off the rod, then came up to pressure about the time it hit the
ground -- even that only traveled about 15 feet, but had the grass been
shorter it would have been a most "entertaining" land shark.

So no, I don't think you have much to worry about from CATOs of Estes
motors at the end of 15 feet of launch wire.  Make sure your rockets are
stable, and all should be well.

--
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://members.aol.com/silntobsvr/launches.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 
 
 

Mosquito: Launch/Find/Relaunch world record = 17 ????

Post by The Silent Observe » Mon, 01 Dec 1997 04:00:00


Quote:



> > 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.

Quote:
> > 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.