Cesaroni 38 MM problem cato & not the good Bruce Lee kind

rfjustin said:

Flight and landing in question is here: https://youtu.be/b03cvpaKWUE?t=18m45s

It does not appear to me that the motor CATO'd.

Click to expand...

Was it the blue rocket that was launched at 8:00 into video? Something happened 8:13.

timbucktoo said:

Was it the blue rocket that was launched at 8:00 into video? Something happened 8:13.

Click to expand...

No sir... Its the red rocket that begins at 18 minutes 45 seconds.

I've seen some CTI's blow right at burnout... if the nozzle plugged up it's possible it'd blow the forward.

Did the ejection charge blow, and if so why'd the rocket not deploy?

That is weird. The boost looked optimal, but no deployment. I would love to see that motor. I would get it apart.

I don't think you're getting it apart, I tried pressing with a giant C clamp & a socket. I heated with a propane torch > tried baking
it in a 450 degree over for 3 hours & whacking the crap out of it with socket & wood mallet, no luck. Same thing as before, start easy
and move up to more rugged methods.
As you can see all I did was to get it budged about 1/4" inch from the end. Case is useless & deformed now. With the last case I finally
decided to trash it & cut it open, and the 2 spacers were still welded in place.
This is 2 for 2 with 2 motor cases & 4 spacers trashed not to mention 2 rebuilds of rockets that I spent considerable time on. If Cesarooni
does not get their act together I'll not be flying them.

Wow. Have you or Tim Lehr contacted CTI about this yet?

Also, I would really consider filing a mess report on the failure.

Tim Knows, in the works I guess.

I see you got the spacers to move a little. They were all most flush with top the case.

Maybe I didn't see the video right (on my phone) but is there a bright flash right at burnout?

Also is there a burn through on the liner?

Did it bend the motor casing - try rolling on a table and see if it is bent - could've bent on landing

Yes, after heating in the oven I beat the crap out of it when it was obvious it was not going to move.
Bye bye to another $50.00

Maybe this photo will be helpful. The plastic sleeve burned through apparently at the end of the propellant burn.
Hence the normal looking boost cycle (see Justins' video, thanks Justin!) Clearly the plastic case burned through,
separating the end closure while delivering a superheated glob of plastic & remaining propellant that welded 2 spacers to the case
and welded the front closure to the top end of the case. Yes I used 2 spacers with a 1 grain motor in a 3 grain case. Yes it was
hand snugged per directions.

What reload type was this motor?

G-69 skid made in march 2016.

hmm, wonder if soaking in gasoline would have dissolved the plastic.
Rex

Thanks for noticing, I guess I finally have CLOSURE (HAH) on this. Attached is Cesaronis' bulletin about this.
They knew they had a problem, and offered a free fix to the dealers. Problem is that the dealers did not get the
fix to all the consumers. I wonder how many dealers addressed the problem? Sure cost me a ton o munny.
I think a good question would be- did Cesaroni notify dealers or just post a bulletin on their web site & expect people to ferret it out?


"Pro38 BULLETIN
Forward Closure Failures
June 15, 2016
It has been brought to the attention of Cesaroni Technology Inc this past week that there has been a high failure rate on several types of Pro38 motors due to forward closure failures. Upon investigation, the root cause has been identified as a failure from de-bonding between the adhesive/epoxy and the forward closure wall. This adhesive is used to hold the delay grain within forward closure housing, and when a poor bond occurs under pressure this can lead to hot gases tracking through forward closure interface resulting in the failures shown.
With further investigation into the recent cause, our manufacturing records showed that our resin supplier of the material used while injection molding the forward closure housing had accidently sent one (1) of four (4) box of material which was slightly different. This mislabeled box contained the same material but had an added lubricant/surfactant, which is compounded directly into the resin to promote/enhance flow during the injection molding process. The introduction of this resin lubricant has caused a bonding compatibility issue with the adhesive/epoxy CTI uses during potting of the delay grain within the forward closure assembly. CTI has already discussed this matter with our resin supplier to ensure this does not happen again.
Unfortunately the forward closure housing itself does not have a unique serial date to identify the effected motors. In a side by side comparison between bad & good forward closures it is extremely difficult to visually identify the difference. With a very keen eye, under the proper lighting & reflection conditions there is a tiny difference that can be seen. The surface of the bad forward closures will appear to be slightly "wavy."
Additionally, in a side-by-side comparison the bad forward closures will feel more "slippery" to the touch than the good forward closures. However without a side-by-side comparison this will almost be unnoticeable. Again both of
2561 Stouffville Rd
Gormley, ON, L0H 1G0
Telephone: 905-887-2370
Fax: 905-887-2375
these indicators/checks of bad forward closures involve VERY subtitle difference which will be difficult for people to notice without careful observation.
The forward closure housing itself is a common component amongst all Pro38 reloads and will not be specific to any particular reload, propellant type, or date. Therefore there is no easily traceable way to identify the potentially effected forward closure except for establishing the time frame in which the Pro38 reloads were purchased (i.e. assembled) for our dealers. Our records for injection molding production show that the four (4) boxes of resin material in question were used between Oct 22, 2015 to Jan 12, 2016.
From our sales records, the dealers that purchased Pro38 reloads that are "potentially" infected by this issue between those dates are indicated below.
Oct 2, 2015 (Invoice SW1338) - Off We Go
Oct 2, 2015 (Invoice SW1340) - Wildman Rocketry
Nov 3, 2015 (Invoice SW1345) - Australian Rocketry
Nov 6, 2015 (Invoice SW1346) - Rockets and Things
Oct 23, 2015 (Invoice SW1348) - Wildman Rocketry
Nov18, 2015 (Invoice SW1349) - Rebel Space
Nov 4, 2016 (Invoice SW1351) - Good Luck Rocketry
Nov 12, 2015 (Invoice SW1347) - Animal Motor Works
Dec 3, 2015 (Invoice SW1357) - Performance Hobbies
Dec 14, 2015 (Invoice SW1359) - Wildman Rocketry
Jan 5, 2016 (Invoice SW1360) - Chris` Rocket
Jan 27, 2016 (Invoice SW1361) - Apogee Components
Jan 11, 2016 (Invoice SW1362) - Animal Motor Works
Jan 29, 2016 (Invoice SW1371) - Animal Motor Works
Again not all of these ProX reloads will necessarily have faulty/bad forward closures. However CTI understands the work & effort the HPR community places into their model rockets and how devastating it can be if a failure occurs. As such to rectify this issue CTI will supply all of the listed dealers with replacement forward closures. Any HPR customer who believes they may have a "potentially" affected forward closure can contact their ProX dealer where they purchased the reload. The dealer will provide at no cost the replacement forward closure. Please identify to your dealer in advance the exact reload model number to receive the appropriate forward closure/delay module. Please dispose of the faulty forward closure/delay module as outline in the instructions and SDS.
We sincerely apologize for any inconvenience or hobby rockets that have been effect by these forward closure. For any hobby rocket failures in flight that occurred as a result of this forward closure issue please follow the regular warranty process by contacting your ProX dealer. The dealers will then provide all the details to CTI so we can ensure you receive the appropriate warranty.
Sincerely,
Cesaroni Technology Inc
2561 Stouffville Road
Gormley, Ontario
L0H 1G0
Phone: 905-887-2370
Fax: 905-887-2375
Web Site: www.cesaroni.net www.pro38.com

I would guess all dealers were told of the problem. But how a dealer would get info out to all who purchased the bad motors from them. Even if he could get info to all the buyer could have resold or traded motor to someone else. I know how you feel I lost a rocket worth about $400 2 years ago from a motor problem I didn't now about.

Yes this was, and is still, an issue. That said, it was widely discussed on TRF.

I do believe there needs to be improved comma on things such as this. Also need folks to hit motorcato.org when they have motor issues and fill out a mess report.

I purchased a 38mm CTI reload from AMW last weekend and as part of the purchase process they inspected the front closure to make sure it was not one of the defective ones. As you cannot tell the bad ones just from the date codes alone, they should all be checked.

tstone said:

Thanks for noticing, I guess I finally have CLOSURE (HAH) on this. Attached is Cesaronis' bulletin about this.
They knew they had a problem, and offered a free fix to the dealers. Problem is that the dealers did not get the
fix to all the consumers. I wonder how many dealers addressed the problem? Sure cost me a ton o munny.
I think a good question would be- did Cesaroni notify dealers or just post a bulletin on their web site & expect people to ferret it out?


"

Click to expand...

CTI notified their dealers, NAR, and Tripoli. It was posted here on TRF, the Tripoli Forum, and the NAR website. Some dealers went so far as to send out notifications to those who signed up for dealer notices. I'm not sure what more could have been done. It's probably a good practice to check some of those usual places from time to time.

By the way, If you have any Aerotech DMS 54mm motors please also be sure to look for that advisory.



Steve Shannon

Thats' just the answer I was looking for. You were dealt with squarely & professionally & your dealer prevented a mishap.
We're not all 'joe rocket' that knows everything.