C 11-7 Strikes

[stmoon]

Hi guys
Had C -11-7 cato on a Estes red flare rocket for a night flight at club launch .
It survived mostly.

 

[mh9162013]

Well, Estes called it the Red Flare for a reason...

But seriously, bummer on the CATO, but great picture!

 

[cls]

Amazing cato picture! Thanks for posting. Glad the rocket survived.

 

[bad_idea]

Sorry this happened to you, but on the positive side, that's an all-time-great CATO photo.

 

[PDawg]

Can you see those lights well at Apogee?

 

[kuririn]

You are about 10 days too early.

 

[ljwilley]

Estes C11, D12, E9, E12, E16, and F15 rocket motors are the most vulnerable to CATOs because of their size. The bigger the motor, the more likely the propellant inside may crack and break. This results in some manifestation of an explosion. I ALMOST lost my beautifully painted Estes V2 on an E12. Luckily I only lost an engine block! Too bad about your rocket...

P.S. That is a really cool picture!!

P.P.S. Estes needs to look into their bigger motors CATOing- I know people who have emailed Estes about it and Estes literally ignores their emails. I think Estes just doesn't want to deal with it.

 

[kuririn]

Estes C11, D12, E9, E12, E16, and F15 rocket motors are the most vulnerable to CATOs because of their size. The bigger the motor, the more likely the propellant inside may crack and break.

That wouldn't explain the proliferation of mini motor CATOs.

 

[mh9162013]

Estes C11, D12, E9, E12, E16, and F15 rocket motors are the most vulnerable to CATOs because of their size. The bigger the motor, the more likely the propellant inside may crack and break. This results in some manifestation of an explosion. I ALMOST lost my beautifully painted Estes V2 on an E12. Luckily I only lost an engine block! Too bad about your rocket...

P.S. That is a really cool picture!!

P.P.S. Estes needs to look into their bigger motors CATOing- I know people who have emailed Estes about it and Estes literally ignores their emails. I think Estes just doesn't want to deal with it.

You sure about the size thing? Because A10 mini engines are notorious for their CATOs...

 

[ljwilley]

I said that those motors are more likely to have CATOs. I've actually had an A10 Cato on me. The reason of the CATO may not be the same, or the manufacturing method of the A10 may be the cause. From what I have heard, the reason that they don't make black powder motors in a larger size is because they would be extremely prone to cracking propellant.

 

[mh9162013]

I said that those motors are more likely to have CATOs. I've actually had an A10 Cato on me. The reason of the CATO may not be the same, or the manufacturing method of the A10 may be the cause. From what I have heard, the reason that they don't make black powder motors in a larger size is because they would be extremely prone to cracking propellant.

So if there's a positive correlation b/w size and CATOs, wouldn't 18mm engines CATO more than the A10 mini engines?

 

[kuririn]

The E9 was notorious for CATOS.
I have had E12 motors CATO on me.
Recently I had two F15s CATO on the same day.
And an E16 destroyed my E launch pad a few years ago.
Burned clean through the steel deflector and melted the legs.
But by far the highest incidence of CATOS have come from A10 mini motors.
No comparison.

 

[ljwilley]

I think that there may be slightly different ways of manufacturing motors. All I am saying is that in my experience d11-f15 motors have been WAY more prone to CATOing than standard motors, and the larger size would logically be more prone to cracking. Yes, the A10s are also very prone to CATOing, and I can't explain that, but all of the largest motors are way more prone to CATOing than standard size, and I think that may have something to do with the size. Yes though, you are right about A10s

 

[ljwilley]

Also it's just my theory, not a confirmed fact, so I don't know for sure.

 

[smstachwick]

The mechanism of BP CATOs is well-known. Cracked propellant or other defects produce a spike in operating pressure and rupture the seal created by the casing and the internal guts of the motor (nozzle, unburned propellant, delay grain, ejection charge, cap). These issues commonly arise in storage or transport. Temperature cycling is known to be the biggest factor, and within that, freezing is a bigger enemy than excessive heat.

Therefore, large motors (which are most prone to developing this wear in storage) or any motor operating at high pressure, or generating a large amount of thrust anywhere in their burn, are most vulnerable. This corresponds nicely with the thrust figures for vulnerable types. The A10 in particular has a max thrust of 12N, very large compared to the rest of the Mini Motor line. The rest are 24 or 29mm.

The line of fractional or full A3s in 13mm, as well as 1/2A-C sized motors in 18mm are not quite as prone, for precise reasons that are beyond me. I suspect it’s because they have superior nozzle designs that can generate their certified thrust figures at lower operating pressures. They have nozzles designed to fit the orange, yellow, blue, or pink plugs. The high-CATO-risk types use green, black, or white.

Occasionally errors on the line or wear on the Mabel machines will make some production lots more susceptible. Estes just put out a service bulletin for a specific production lot of A10s, probably for one of these reasons.

 

[ljwilley]

That makes sense.

 

[Back_at_it]

I feel your pain. Had my second every CATO at a club launch this weekend with an A10-3 motor. Rocket survived, no harm down but it was exciting.

 

[gldknght]

I was the guy on the pad next to Stmoon. Right after his C11 cato'd, I had a cato on an Estes D12. My rocket did not fare quite as well. The top half above the separation joint had no damage. I though most of the fin can area would be salvageable to rebuild the rocket, but a closer inspection at home showed the entire lower half of the rocket was badly cooked. I mean it was black, blistered and peeling. There's no way I'd even be able to install a new motor mount or centering rings.

This was the very first time I've ever had an Estes motor cato in over 40 years of model rocketry.

 

[icyclops]

Hi guys
Had C -11-7 cato on a Estes red flare rocket for a night flight at club launch .
It survived mostly.

Wow, what a shot…