CTI 38mm I540 CATO

Launched my new 3" FG DD yesterday. The CTI motor CATO'd at 225 ft. The onboard Mobius camera caught some great video
.

Full video
[video=youtube;vvYvrWPdwd0]https://www.youtube.com/watch?v=vvYvrWPdwd0[/video]

Photos
1. Adapter ring falling away
2. Nozzle
3. Adapter
4. Case blew forward into lower section. This separated lower section from AV bay. Not intended. Case falling out of lower section. You can see a ding in the front end of the motor case when it slammed into the eyebolt.
5. Fuel grain
6. Nosecone, upper section and AV bay prior to main chute deploy.
7. Initial motor failure.
Because the lower section was to stay attached to the AV bay the failure caused the lower section to slide down and make contact with the fin can after the main chute deployed. The sections were attached with 3 plastic rivets.

AV bay was equipped with Altus mini, RRC2 and Eggfinder GPS.
All 4 charges fired and Rocket was recovered with no damage.

Nice straight flight but shorter than intended. Max altitude 550 ft.

Pretty cool video, glad there was no damage to the rocket. The audio sounds like a sinking ship twisting metal and all.

great video! can you tell us about your assembly method for the motor?

Double check length on igniter, kink leads at nozzle to insure full insertion at launch pad.
Insert single spacer(this is a 5 grain in a 6 grain case)
Insert motor and thread nozzle/aft enclosure. tighten firmly. Make sure nozzle assembly is fully threaded in.
Had my Buddy, an L2 check my work.
I have loaded quite a few CTI 38mm and other sizes. This is the first CATO

n27sb said:

Make sure nozzle assembly is fully threaded in.

Click to expand...

all the way in or was there a gap between the case and the nozzle/aft closure?

per the CTI instructions there should be a gap, but not greater than 1/16"

What was date of manufacture on the tube motor came in?
Have it ready.
Then contact your dealer or CTI.
Show him all the parts/pictures & go from there.

Best way to know what happened & possibly get a warranty replacement....if not user error.:wink:

RKeller said:

all the way in or was there a gap between the case and the nozzle/aft closure?

per the CTI instructions there should be a gap, but not greater than 1/16"

Click to expand...

Yup, The gap and snugness was correct.

blackjack2564 said:

What was date of manufacture on the tube motor came in?
Have it ready.
Then contact your dealer or CTI.
Show him all the parts/pictures & go from there.

Best way to know what happened & possibly get a warranty replacement....if not user error.:wink:

Click to expand...

Bought this from the vendor on site. He said he will take care of it. He is always the best

n27sb said:

Bought this from the vendor on site. He said he will take care of it. He is always the best

Click to expand...

Gotta love field vendors!

Meant to add:

Glad your rocket was OK.

n27sb said:

Bought this from the vendor on site. He said he will take care of it. He is always the best

Click to expand...

Bernie is the man!

Same exact thing happened to my wife at the last Red Glare launch. Same load, Very experienced with the Pro-X system (aware of the "Gotchas"), Same care taken on the same details. Rocket was a LOC Fantom 438 EXL. Similar flight/CATO profile; Hers blew the fin can apart when everything failed at the rear. Altitude was about 125'-150'. No Spacer though, had a brand new 5grain case. Shoved the case up through the booster airframe and into the Av Bay so hard that the impact deployed the main. Fortunately the onsite vendor determined it was a defect and made good on the load and replaced the case just to be on the safe side. I don't recall what the lot number and MFG date were. The Rocket has since been repaired. Just waiting for her lazy husband to give it a new paint job.

timbucktoo said:

Bernie is the man!

Click to expand...

Your right about that. Bernie is a huge asset to have at launches. Good prices, good stock and a great wealth of knowledge.

stantonjtroy said:

Same exact thing happened to my wife at the last Red Glare launch. Same load, Very experienced with the Pro-X system (aware of the "Gotchas"), Same care taken on the same details. Rocket was a LOC Fantom 438 EXL. Similar flight/CATO profile; Hers blew the fin can apart when everything failed at the rear. Altitude was about 125'-150'. No Spacer though, had a brand new 5grain case. Shoved the case up through the booster airframe and into the Av Bay so hard that the impact deployed the main. Fortunately the onsite vendor determined it was a defect and made good on the load and replaced the case just to be on the safe side. I don't recall what the lot number and MFG date were. The Rocket has since been repaired. Just waiting for her lazy husband to give it a new paint job.

Click to expand...

Was your engine a Blue Streak or White Thunder?

blackjack2564 said:

Meant to add:

Glad your rocket was OK.

Click to expand...

Thanks Jim. It was a Rocketry warehouse Aventurer 3. It is heavy but built like a tank. I added a FG piston to it so the case hit the piston and the kevlar cord underneath it cushioned the blow.
It did rack up the piston a little but easy patch job. Could have done it with Quick JB.

Who is Bernie?

n27sb said:

Was your engine a Blue Streak or White Thunder?

Click to expand...

It was a White. She'd flown 4 or 5 times previously on the same load; no problems. In fact, that rocket/motor combination was one of the best performing I've ever seen.

crossfire said:

Who is Bernie?

Click to expand...

Bernie is the CTI vendor at NEFAR & Spaceport Rocketry Assn.

Hello Steve,

Sorry to hear about your CATO. I'm glad to read that the dealer took care of the warranty on the spot. I'd appreciate it if you can PM me the date(s) stamped on the cardboard packing tubes for our records.

Just a reminder for everyone reading this. There was a product advisory on Pro38 White Thunder: https://www.rocketryforum.com/showthread.php?53514-CTI-38mm-White-Thunder-Recall&p=526665#post526665 . If anyone still has a Pro38 White Thunder reload with 2/20/13 date code, please make sure to arrange exchange with your dealer (Pro38 only, no other loads with the same date).

Thanks,
Jeroen - CTI

The number of CTI 38mm CATO's I see is a little unsettling. at one launch I saw 3 or 4 within a couple hours. I know the 38mm nozzle/closure setup is very sensitive to improper installation, but then you see it happen to experienced flyers who know what they are doing. one fatal error I have seen people make is to bang the threaded end of the case on a hard surface to get the load out after a flight. the threads get damaged and then the next load goes boom when the plastic threads get all garbled up going in. I actually bought my 38mm hardware from a guy who wouldn't use it because he had seen so many CATO. I guess I would have to ask, is there an issue with the CTI 38mm design? why not just use an aluminum retainer just like the 29mm?

I don't know if it helps but I grease the threads in mine

RKeller said:

The number of CTI 38mm CATO's I see is a little unsettling. I guess I would have to ask, is there an issue with the CTI 38mm design? why not just use an aluminum retainer just like the 29mm?

Click to expand...

The alternative is you now have reloads for older case style and new case style. Not economically feasible for CTI. Or new design cases and all the 38mm cases I have are obsolete. Not economically feasible for me... Have CTI swap out all the old hardware for new style? Also not economically feasible for CTI. Now maybe they could reinforce the threads of the reload case with some sort of metal insert, but I'm sure that would be reflected in a price increase. True, I've only used the 6xl case in the 38mm line so far, but I'm still burning AT reloads from 1999...

Adrian

RKeller said:

The number of CTI 38mm CATO's I see is a little unsettling. at one launch I saw 3 or 4 within a couple hours. I know the 38mm nozzle/closure setup is very sensitive to improper installation, but then you see it happen to experienced flyers who know what they are doing. one fatal error I have seen people make is to bang the threaded end of the case on a hard surface to get the load out after a flight. the threads get damaged and then the next load goes boom when the plastic threads get all garbled up going in. I actually bought my 38mm hardware from a guy who wouldn't use it because he had seen so many CATO. I guess I would have to ask, is there an issue with the CTI 38mm design? why not just use an aluminum retainer just like the 29mm?

Click to expand...

I've flown hundreds of CTI 38's and never had an issue. Keep in mind that even experienced flyers can make mistakes. After talking to the flyer, the very few CTI CATO's that I have witnessed it was clear that they were the result of user error.
I did have one 4 grain case that wasn't threaded properly, but instead of forcing the reload in, it was returned and replaced. Also had a J394 with a slightly too long liner, this was trimmed back to allow the nozzle threads to engage at the proper depth.

The design has been around for years. When they first came out with it they worked great. I flew them all the time. I did my L2 with a J285. I don't know what's going on with there quality control. I have seen more CTI loads CATO over the last 3 years then any other commercial motor.

jd2cylman said:

The alternative is you now have reloads for older case style and new case style. Not economically feasible for CTI. Or new design cases and all the 38mm cases I have are obsolete. Not economically feasible for me... Have CTI swap out all the old hardware for new style? Also not economically feasible for CTI. Now maybe they could reinforce the threads of the reload case with some sort of metal insert, but I'm sure that would be reflected in a price increase. True, I've only used the 6xl case in the 38mm line so far, but I'm still burning AT reloads from 1999...

Adrian

Click to expand...

yeah, it's not an easy problem to fix, if there even is a problem. I don't think anyone would need new hardware, just a rear closure. I know there is a risk of a CATO with any motor, and there are thousands of 38's flying with no issues, that's why I bought CTI 38mm hardware. if I had to buy a $25 rear closure that fit my existing hardware I wouldn't complain, it would take away that "gee I hope these plastic threads hold" feeling.

RKeller said:

The number of CTI 38mm CATO's I see is a little unsettling. at one launch I saw 3 or 4 within a couple hours. I know the 38mm nozzle/closure setup is very sensitive to improper installation, but then you see it happen to experienced flyers who know what they are doing. one fatal error I have seen people make is to bang the threaded end of the case on a hard surface to get the load out after a flight. the threads get damaged and then the next load goes boom when the plastic threads get all garbled up going in. I actually bought my 38mm hardware from a guy who wouldn't use it because he had seen so many CATO. I guess I would have to ask, is there an issue with the CTI 38mm design? why not just use an aluminum retainer just like the 29mm?

Click to expand...

No. The 38 mm CTI casing design is sound. The usual source 38mm cato is cross-threading the nozzle or failing to insure that the nozzle threads in fully engaged. Or someone abusing the casing by deforming it......

I don't think CTI has any more catos than AT or any other manufacturers motors. With any rocket motor there will be occasional production lots that do not get caught during the QC where 2% of the motor production are static tested. A sporadic mechanical debonding such as in the mentioned White Thunder lot probably won't show up in the QC testing but once observed in the field was recalled by CTI. AT had problem with certain reload lots in the past and also recalled them. That's why it's important to let the manufacturer know of a motor failure and to also report it to the certifying authorities via motorcato.org

Bob

bobkrech said:

No. The 38 mm CTI casing design is sound. The usual source 38mm cato is cross-threading the nozzle or failing to insure that the nozzle threads in fully engaged. Or someone abusing the casing by deforming it......

I don't think CTI has any more catos than AT or any other manufacturers motors. With any rocket motor there will be occasional production lots that do not get caught during the QC where 2% of the motor production are static tested. A sporadic mechanical debonding such as in the mentioned White Thunder lot probably won't show up in the QC testing but once observed in the field was recalled by CTI. AT had problem with certain reload lots in the past and also recalled them. That's why it's important to let the manufacturer know of a motor failure and to also report it to the certifying authorities via motorcato.org

Bob

Click to expand...

The design is sound, but it isn't very robust. the plastic threads are easily crossed or deformed by a damaged case. I design things that have to function in some pretty crazy environments for a living. often the hardest part is making it so the people putting it together or working on it can't screw it up.

Totally don't agree at all....doing this hobby since 1994 and never had issues with AT...seen 10 fold more CTI catoes than AT ...prep/assemble your own motors people, how do you know that pre-assembled motors are put together correcty? All trust goes to the manufacturer, it's so easy to screw a motor in a metal tube assuming it'll work....let the complaining begin!! What abuse are we talking about? Cross threading or failing to insure nozzle threads are fully engaged? Is this info direct from CTI? If so please share link where this can be found.

bobkrech said:

No. The 38 mm CTI casing design is sound. The usual source 38mm cato is cross-threading the nozzle or failing to insure that the nozzle threads in fully engaged. Or someone abusing the casing by deforming it......

I don't think CTI has any more catos than AT or any other manufacturers motors. With any rocket motor there will be occasional production lots that do not get caught during the QC where 2% of the motor production are static tested. A sporadic mechanical debonding such as in the mentioned White Thunder lot probably won't show up in the QC testing but once observed in the field was recalled by CTI. AT had problem with certain reload lots in the past and also recalled them. That's why it's important to let the manufacturer know of a motor failure and to also report it to the certifying authorities via motorcato.org

Bob

Click to expand...

Folks often forget to review the directions.

Of the 38 mm CTI motors I have seen fail, the great majority of the failures appear to be due to improper assembly by the user, either by cross threating or failure to tighten the nozzle properly, and I've seen one where the user failed to put the reload in the metal casing....and if you bang up any reload casing to remove a stuck liner, and damage the casing, and then go use it and it fails, it's not the manufacturer's fault...... The Pro38 reload instructions are located at https://www.pro38.com/pdfs/Pro38Instns.pdf and address the concerns/issues mentioned above.

The average flyer is not an experienced L3 person like you are. I've probably seen 3,000 to 5,000 launches a year for the past 15 years and have observed more AT failures than CTI failures. That's not surprising to me as the chance of improperly assembling an AT motor is higher because they have more user installed parts and frequently use different size O-rings and internal configurations in the same casing size.

Bob

Are all the CTI 38 mm rear closures the same? Could they be replaced by one optional aluminum closure for those willing to invest in it? I would expect that other reloads for 38 mm could be developed that are not currently possible due to limitations of the plastic rear closure.