Opinions on a CATO

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dhkaiser

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This was not my rocket, I just happened to be photographing a club launch when this occurred. It was an Estes Interceptor with an E something motor.

What I find interesting and somewhat scary is the flying object going sideways. Has anyone witnessed something like this? Has anyone ever been injured by something like this?

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I've had that happen with an E9 in my Mega Mosquito. It had the same burning object out the side. I figured it to be a piece of the BP propellant getting spit out while burning. The flame burnt out before it even hit the ground (10 ft away) so I don't see how it could do much since you are supposed to be at least 15ft away. :wink:
 
Seems to be happening with alarming frequency with the Estes E motors. I've seen several myself, some that threw parts of the rocket and burning bits over 20 feet with enough energy to break skin. No thanks. We've moved anything larger than a D motor from the LPR line back to the MPR safety line because of it.
 
I've caught "a few" CATO's on flim. From tiny BP to big old M's Damage varies of course. With a BP E, the usual destruction involves the clay nozzle just giving up. This one looks like it spit a chunk of burning BP off the blast plate.

If you're following safe distance procedures, you should be ok. Even if you got hit with that, it's just burning BP. While not great for you, it won't be too significant a burn.


I've seen more E12's pop than E9's

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Seems to be happening with alarming frequency with the Estes E motors. I've seen several myself, some that threw parts of the rocket and burning bits over 20 feet with enough energy to break skin. No thanks. We've moved anything larger than a D motor from the LPR line back to the MPR safety line because of it.
E-motors are mid-power by definition and should not be launched from a low power pad. Motors in the D-impulse class and lower are classified as low power and have a minimum separation distance of 15'. Motor in the E-impulse to G-impulse class are classified as mid-power and have a minimum separation distance of 30'.

From the model rocket safety code.

5. Launch Safety. I will use a countdown before launch, and will ensure that everyone is paying attention and is a safe distance of at least 15 feet away when I launch rockets with D motors or smaller, and 30 feet when I launch larger rockets. If I am uncertain about the safety or stability of an untested rocket, I will check the stability before flight and will fly it only after warning spectators and clearing them away to a safe distance. When conducting a simultaneous launch of more than ten rockets I will observe a safe distance of 1.5 times the maximum expected altitude of any launched rocket.

Bob
 
This happens at least once every couple of club launches. I have had like 3 the past year. The burning nozzle pings off the blast deflector and the ejection and delay charge blow out the top of the rocket in a nice fireball. Some times they just blow the bottom nozzle and burn out nice and slow.

AT single use composite CATOs are even better.

I have never seen anyone even close to being hurt by one of these at bimonthly club launches for eight years now.

I do believe, however, our Pad Fuehrer is quite tired of our disparaging remarks regarding Quality Assurance of these certified single use motors.
 
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The best wrecks have been the AT SU H motors going Roman Candle after leaving the rail then burning stove pipe on the ground. Two launches ago I saw a typical 29mm SU failure blow out the side of an ARCAS fin can, ejection blow off the cone, but then a slow yet intense burn on the pad was a bit new and exciting. Last year after one of my 24mm SU F44's blew the forward closure I gave the other one from the pack to a friend at NARAM with many warnings, he wanted to launch one in his old D Region Tomahawk. That massive 24mm composite CATO was cool, better than us usual 24mm whoosh popper BANG CATO. I don't know the numbers but the SU composites will CATO just like the BPs. Lots of factors come into play and there are bad batches of both types.


Although the BP CATOS can be really cool in a cluster, one blows and two light on the MR 171 - cool, it still flew and maybe I can get a hold that awesome video some day.

One E blows in a pod and takes the core F motor igniter with it, then the other two Es light in other the pods, not so cool but good wreckage on a PS II kitbash.

All of this has happened at club launches in a safe environment. CATOs will happen so keep your head up and don't freak out. The odds are with you.
 
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The safety codes/minimum launch distances are there for a reason, and not arbitrary numbers. You're more likely to get into a car accident on the way to/from a launch than have something happen AT the launch if the rules are followed.
 
This was not my rocket, I just happened to be photographing a club launch when this occurred. It was an Estes Interceptor with an E something motor.

What I find interesting and somewhat scary is the flying object going sideways. Has anyone witnessed something like this? Has anyone ever been injured by something like this?

Yes, there was apparently someone here in GA who got a very bad burn on the side or thigh from a cato. I came upon the report during a search on the web for something else, but there was a photo entered as evidence and it was somewhat gruesome. The person survived fine (it looked worse than it was apparently), and there was no other description so it couldn't be said whether the person was following all safety precautions. In general, the sideways projectiles I've seen burn out well within 10 feet. The upwards debris (probably the delay material) burns longer, but usually is consumed within two seconds.

In your photo, that seems to be something that was ejected out the back, but deflected by the blast deflector (It would be better if we had true deflectors, but a flat plate is usually the best we can do).
 
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