RATTWorks K240 CATO

This past weekend at NYPower we had quite the interesting failure. My dad was flying his 4" ASP on the RATT K240, and about 2 seconds into the burn, it CATO'd...spectacularly. Everything was recovered, including all parts of the motor. Here are a few pics.

The only leads we have is that the motor was pulsing while it was burning, which is not normal. Also, the smoke turned black a few miliseconds before it CATO'd, leading us to believe that it was burning fuel rich...any ideas?

Not pictured is the injector, as we are still unpacking...it's in one of these boxes somewhere...and it's in perfect condition, go figure!

Here is the fuel grain with the graphite nozzle. This shows that the nozzle throat is the same as it was before, yet the entire divergence section is gone!

Here is a picture of the one piece that broke off, and how it goes back together on the case. This is what leads us to believe that the tank ruptured. This could be caused due to Nozzle blockage or the tank sucking in a spark and detonating.

This shows the scorching just north of the injector, again leading us to believe that the tank took in a spark...

Any ideas?

Sorry about the loss, but it is indeed interesting. I assume you'll poll RATT about it.

Yep, the email is going to get written tonight. Doug Pratt is kinda confused about it at the moment, we'll see what Dave says. When Doug doesn't know what happened to a hybrid, it could be serious

Originally posted by DPatell
This past weekend at NYPower we had quite the interesting failure. My dad was flying his 4" ASP on the RATT K240, and about 2 seconds into the burn, it CATO'd...spectacularly. Everything was recovered, including all parts of the motor. Here are a few pics.

The only leads we have is that the motor was pulsing while it was burning, which is not normal. Also, the smoke turned black a few miliseconds before it CATO'd, leading us to believe that it was burning fuel rich...any ideas?

Not pictured is the injector, as we are still unpacking...it's in one of these boxes somewhere...and it's in perfect condition, go figure!

Click to expand...

The pulsing you describe is a good clue. It looks like a flash back and the phenomenon is documented. Dr. Louwers here was able to reproduce it on the test stand and we have good data. N2O is an exothermic monopropellant and for some reason communication may have occurred between the combustion chamber and tank to touch it off. I've posted on this topic before so I wont get into details here. It's very rare in most certified motors and especially with the Ratt motors as far as I know.

Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
https://www.cesaronitech.com/
(905) 887-2370 x222 Toronto
(941) 360-3100 x101 Sarasota
(410) 571-8292 Annapolis

Just an aside- we're still picking up pieces of the rocket.....






Nat
NYPOWER worker-bee

Sorry about the littering of the field...had we known, we wouldn't have done it. We thought we'd be nice and blow it into small enough pieces so that you wouldn't have to bother picking them up. Good thing my dad painted his rocket BRIGHT orange, so each little piece is easily seen in the grass, no matter how small. Please collect all pieces and put them in a small envelope or box, and ship them to...for reconstruction purposes.

"We freaking obliterated that thing," as my dad just stated...

Dan, I was standing in Skybuster row when it went off, front row seat. It was truly spectacular. Never seen anything like it before. For what it's worth, I thought this particular hybrid flight was much, much louder than others I have seen.

wick

Obligatory sarcasm-
I cannot quite put my finger on it, not having used hybrids, but something looks amiss with that motor casing?

Obligatory question(s)-
Pictures?
Videos?

Greg

The RATT K240 is a SWEET motor...when it works, that is...It screams like no other. That flight was pulsing and screaming like mad. Definately the coolest sounding motor ever.

Thanks for the kind words in a period of sorrow The altimeter survived, but on the following flight it popped the chute early (earlier than it normally does...par for the course with RRC2's), so we're sending it in.

No worries on the cleanup- we're not worried about it, at all, even slightly.

I thought (as sad as it is to lose a rocket) that it was pretty funny how fliers kept bringing in hunks of it all weekend! Everyone knew what you were talking about if you mentioned "the cato".

The onsite photographer has a great shot of it pre and post bang. I suppose you probably got one of those?

N

We were going to get a picture, but when we tried to leave, the guy was out in the field doing something. There were a few other people that got pictures of it and they hopefully will be emailing the pics to us...

The debris pile kept expanding throughout the weekend, everyone kept bringing stuff in, as you said. One woman even came up to my dad and was like "That was really cool, that's the first one that I have seen that blew up!"

Originally posted by DPatell
Sorry about the littering of the field...had we known, we wouldn't have done it. We thought we'd be nice and blow it into small enough pieces so that you wouldn't have to bother picking them up. Good thing my dad painted his rocket BRIGHT orange, so each little piece is easily seen in the grass, no matter how small. Please collect all pieces and put them in a small envelope or box, and ship them to...for reconstruction purposes.

"We freaking obliterated that thing," as my dad just stated...

Click to expand...

You mean that wasn't partof the show? The Patells and their amazing confetti rocket? ;-)

Chuck

Chuck's a jokester Someday you'll have to put down the camera and fly a rocket. If you do, I want to be there to video tape the crash :kill:

Originally posted by DPatell
Chuck's a jokester Someday you'll have to put down the camera and fly a rocket. If you do, I want to be there to video tape the crash :kill:

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Deal.

My motor or yours? I'll fly it like it's Bob's rocket.

No shake in the camera and Quicktime 7, please.

Chuck