CATO?
zane
Rick Dickinson
wrote:
>What does this stand for?
"Catastrophe"
It is simply shorthand for "My gosh -- look! Something went horribly
wrong!" (usually in reference to motor failures). It is not an
acronym for anything. In fact, it shouldn't be rendered in all caps,
unless you are shouting....
- Rick "Clouseau's sidekick" Dickinson
--
Twice five syllables,
Plus seven, can't say much -- but...
That's haiku for you. D. Hofstadter
David Weinshenker
> What does this stand for?
"Catastrophic failure" - something goes wrong with the
motor so that it fails to complete its normal firing
sequence (forward blowout, burst casing, spit nozle, etc.)
-dave w
Tom Binford
"zane @erols.com>" <"zgorove<tossspam> wrote in message
news:3B1C899F...@erols.com...
> What does this stand for?
>
Sudden and usually spectacular motor failure.
Tom
Lee
>
>What does this stand for?
Roy Trzeciak-Hicks
--
Roy Trzeciak-Hicks
"The man who smiles when things go wrong has thought of someone to blame it
on."
- Jone's Law
"zane @erols.com>" <"zgorove<tossspam> wrote in message
news:3B1C899F...@erols.com...
tai fu
means your rocket suddenly behaves exactly like a real missile (flies then
goes boom)
--
Email: rocke...@mail.utexan.edu
replace n with s to reply
---
Tai Fu
NAR# 76089 L1
Fred Shecter
"Launch".
CATO is short for Catastrophic Failure and is correctly spelled cato.
Just like "combo" is short for a combination.
-Fred Shecter NAR 20117
Roy Trzeciak-Hicks <R...@hpr.org.uk> wrote in message
news:thp60c8...@xo.supernews.co.uk...
Steven
The word CATO indicates a CATastrOphic ignition of the rocket engine.
CATOs are uncommon, however, when they do occur, they tend to happen mostly
to the larger black-powder Rocket motors - such as C5s, D12s and E15s. The
cause is usually the result of temperature cycling of the motors (such as
leaving them in the trunk of a car and having them get very hot, then very
cold many times). This causes small internal cracks in the compressed powder
which, when ignited, burns at a different rate than it should. If it burns
too fast, it will either blow out thru the ejection charge, or the engine
casing will split. A blow thru often damages the metal blast deflector (a
big dent, if the engine is shot down from the body tube). A CATO that splits
the Engine casing typically destroys the lower portion of the Rocket.
CATOs are also possible with the composite propellants found in Mid and High
power motors, although the cause is not the same. Composite motors are
generally lit at the top, which means that much more of the igniter is
inside the motor at ignition. Especially with the smaller motors/nozzles,
the igniter can stick and plug the nozzle, resulting in an
over-pressurization of the casing. One or both of the closures may get blown
off, or the casing can even rupture. In other cases, improper assembly of
the delay may allow combustion gasses to leak by and light the ejection
charge at liftoff. This also causes flame to shoot out of both ends of the
motor to the detriment of the rocket's interior.
Bob Kaplow
> Catastrophe At Take Off
BZZZZTTTT! GONG! Incorrect.
No matter how many times someone says so, CATO is *NOT* an acronym for these
or any other four words. It is short for CATAstrophic Failure. This acronym
just showed up in the past few years. CATO has been around as long as I've
been going to big rocket launches (1975 at least).
Bob Kaplow NAR # 18L TRA # "Ctrl-Alt-Del"
Kaplow Klips & Baffle: http://www.nira.chicago.il.us/Leading_Edge/MayJun00.pdf
NIRA: http://www.nira.chicago.il.us NAR: http://www.nar.org
"We find that adult supervision stifles our natural creativity" J. Fox 4/27/01
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Fred Shecter
It is not just at ignition. It can be slightly after ignition or even just
before propellant burnout.
That is why it has been and still is simply short for Catastrophic failure.
And temperature cycling does not form cracks in the black powder propellant.
It progressively stretches and shrinks the casing (cardboard) and the
propellant. Since they have different coefficients of thermal expansion,
they enlarge at different rates and the cardboard can remain stretched.
This reduces the propellant to casing bond which allows flame to propagate
up the wall.
You can get a failure just after ignition (seemingly instant) if you have
cycled it enough to cause a crack between the propellant and the nozzle.
Here is my much longer explanation cut & pasted here:
Here is why temperature cycling can cause Catastrophic failures (CATOs). The
nozzle, propellant and the casing all expand and contract at different
rates. Since the motors are so small, this is only a problem if the
temperature that the motor "sees" swings between wide extremes. When this
happens, we see several effects:
1) The propellant and the clay nozzle develop a crack at their interface.
This actually results in *Lower* peak pressure and peak thrust because the
motor can begin the end-burning earlier than it should (never forming the
"big dome" of burning surface area that we should get at normal peak
thrust).
2) The casing and the propellant can de-bond. They aren't really bonded in a
"glue" sense, but the mechanical bond is weakened from the stretching and
contraction. (For wet rammed motors, there may be a tiny glue-like
"bonding", but the cycling will break that bond). The flame can propagate
along the entire inside of the casing and propellant interface and result in
a huge overpressure. This leads to a casing split (if the delay is still
"grabbing" the casing tightly) or a "blow through" which is like a Roman
Candle.
The two of these can combine to form different CATO scenarios:
a) Blow through at ignition or just after ignition (on the pad/rod). Clearly
a sign of a nozzle/propellant interface crack allowing the flame front to
reach the debonded casing to propellant interface at or just after ignition.
b) CATO above the pad (like 50 feet up). Clearly there was no crack along
the propellant/nozzle interface and the flame front had to wait until it
naturally reached the casing wall and then propagate up the de-bonded
propellant/casing interface.
A final scenario if the cracked propellant grain. These can go BLAM (or
KA-PLOW) quite spectacularly since they really overpressurize the casing
big-time and can happen with a perfect casing to propellant bond. A
defective tool used to form the centerbore of the propellant can cause
these. The C5-3 had such a problem when a tool was mis-manufactured. I
believe the root cause was a lack of radius on the tip, which formed a sharp
edge, which led to cracking. F100 motors also could be cracked if dropped or
if any contaminant got on the tool or in the propellant during ramming.
As for the temperature cycling - avoid firing a motor at a temperature 75
degrees F lower than the highest temperature it has ever seen. If fired
while too cold, the propellant will be contracted away from the casing and
it will probably fail. Folks launching in cold weather can do so if they
store their motors in their warn car or in their toasty parka inside
pockets. (Is that an F100 in your pocket or are you just happy to see me?)
I hope this info helps folks.
-Fred Shecter NAR 20117
Steven <shac...@adelphia.net> wrote in message
news:dL8T6.7568$Rq4.2...@news1.news.adelphia.net...
Leonard Fehskens
kapl...@eisner.encompasserve.org.mars wrote
>CATO has been around as long as I've
>been going to big rocket launches (1975 at least).
Further back than that - at the MITMRS we used cato back
around 1969 or 1970.
len.
Chip Jenkins
Go Figure.
Fred Shecter wrote:
>
> Incorrect. Rockets do not "take-off", airplanes do. Rockets "Lift-off" or
> "Launch".
>
> CATO is short for Catastrophic Failure and is correctly spelled cato.
>
> Just like "combo" is short for a combination.
>
Fight the urge, Rick!
:-)
Chip
Fred Shecter
One of our club members flew his Estes Cato accompanied by his Green Hornet
model.
8-)
-Fred Shecter NAR 20117
Chip Jenkins <cjen...@neo.rr.com> wrote in message
news:3B1D546F...@neo.rr.com...
Kevin Rich
--
Kevin
TRA # 8732 Lvl 1
FAA Senior Parachute Rigger