CTI Discussion Thread

Wildman Rocketry
the model rocket show
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
SnapRoll said:
Being part Canadien I thought the same and really supported the CTI product.. the bigger motors assemble more like an Aerotech however so as you get into bigger stuff, your feelings might change.

I’m frustrated beyond belief with the CTI 54mm collection.
Click to expand...
I just got a 54mm J280 Smokey Sam to do my Level 2 with, so what's the problems?
 
hobie1dog said:
I just got a 54mm J280 Smokey Sam to do my Level 2 with, so what's the problems?
Click to expand...
It seems the longer motors have weird CATO tendencies.. IMHO it seems the 4/5/6/6XL motors overpressurize and blow holes through the casing turning the rocket into a blow torch. I have a K490, and a K300 that are a mirror image of the picture the guy above just posted.

The lack of a forward seal disc is a head scratcher..
 
SnapRoll said:
It seems the longer motors have weird CATO tendencies.. IMHO it seems the 4/5/6/6XL motors overpressurize and blow holes through the casing turning the rocket into a blow torch. I have a K490, and a K300 that are a mirror image of the picture the guy above just posted.

The lack of a forward seal disc is a head scratcher..
Click to expand...
that's scary. I have put a lot of time in my rocket and it's a real beauty.
8yWYiB6.jpg
 
SnapRoll said:
It seems the longer motors have weird CATO tendencies.. IMHO it seems the 4/5/6/6XL motors overpressurize and blow holes through the casing turning the rocket into a blow torch. I have a K490, and a K300 that are a mirror image of the picture the guy above just posted.

The lack of a forward seal disc is a head scratcher..
Click to expand...
I have only personally seen it happen with 6gxl cases, but in both 38 and 54 mm.
 
It's a significant problem with 4g+ 54s burning out through the forward closure that gluing has become the de facto field fix, but it's not 100% guaranteed. It's been demonstrated in several threads.

To a lesser extent, the short 54s blow at the aft end where the nozzle seats at the liner.

I've personally seen several of both issues at Bayboro and MDRA launches.

CTI has acknowledged the issue with the fwd closure failures of the long 54s and hinted that they may be working on a fix in the form of a re designed forward closure.......but that was pending a test rig coming back into service......and a while ago!

The issue of forward closure failures in long motors seems to have infected the long 38s, too. Same field fix, but no idea if there is as widespread issue.

I thought I was over the fear of the 2016 38mm forward closure issue.....until I got an UN-serviced one from a vendor last year that was squarely in the middle of the failure lot!
 
Last edited:
I've flown a lot of long 38's and 54's, and I've never had a CTI forward closure failure. In fact, the only CTI failure I've ever had was the infamous oversized BP pellet issue with a 29/3G G33... it blew my Saturn V in half on the pad.
 
hobie1dog said:
that's scary. I have put a lot of time in my rocket and it's a real beauty.
8yWYiB6.jpg
Click to expand...
I would posit a few things:
1. I am also a CTI flyer and I love the ease of assembly. There's nothing wrong with liking that and appreciating it. For me, it's less about manual dexterity/strength and more about turning cases around at the field. For example, at my last launch, I flew two rockets on the same case in less than 2 hours, and that included time to recover the first one.
2. A J280 is a 2 grain motor, which is pretty far outside the range of motors that have had the forward closure problems. It's also a pretty short burn (2.5s), and it seems like many of the motors with problems are longer burn (3.5+s).
3. Epoxying in the forward and aft closures doesn't hurt anything, so you might as well do it the day before launch. Just make sure you adjust the delay if you haven't already!

That is a beautiful rocket!
 
The other thing that I would recommend is to grease the liner. I'm not talking about lubricating the liner, but rather, heavily greasing it to fill the space between the case and the liner.

Jim
 
Since none of these 'field fixes' have been approved, endorsed or authorized by CTI..That pretty much makes these motors fall into the Research realm. Which may void any insurance you think you might have.

Tony
 
SnapRoll said:
That’s prolly because it’s cheaper to keep issuing warranty motors as opposed to re-certify the motor with a new design..
Click to expand...
Changes which are fixes to problems don’t always need recertifications. They just need approval of the certification authority. This problem didn’t always exist. Lots of long CTI motors flew with very few issues.
Also, for an established manufacturer, even if they did resubmit the motor for some reason, it’s less than replacing six motors under warranty and there have been more failures than that.
 
Its weird with the long 54s, a lot of people report forward closure issues, but the two K300s I bought both failed at the nozzle end.

I’ve flown other long 54s in the past with no issues, but looking at user reports here and on motorcato.org had me returning the K1440 I got a couple years ago. It’s a shame because I was really looking forward to flying that motor. I did however buy an L935 that I’ll be flying in a couple weeks, so hopefully that goes well.
 
Steve Shannon said:
I have only personally seen it happen with 6gxl cases, but in both 38 and 54 mm.
Click to expand...
This year at NYPOWER I had a CTI 6 grain K820 Blue Streak cato and I'm still waiting for my motor vendor to receive and replace the load. He already replaced the 6 grain casing and aft closure. It seems to me that almost two and a half months is quite some time to get-r-done. I know of one other flyer in our club who experienced the same issue with the same motor and received warranty replacement. If I remember correctly, I did a MESH report shortly after returning from NYPOWER anf I'm preaty sure Dennis did one the year before.
 
tfish said:
Since none of these 'field fixes' have been approved, endorsed or authorized by CTI..That pretty much makes these motors fall into the Research realm. Which may void any insurance you think you might have.

Tony
Click to expand...
Which fixes are you referring to? If it's greasing the liner, that is not an issue that would cause a motor to fall into the research realm or void insurance.
 
I've flown a half dozen or more 5, 6, 6XL 54 mm motors and never had an issue. Maybe I'm just lucky, but...

My personal opinion is that the issue may be more about the forward o-ring than anything else. I don't believe you can get enough hot gas flowing between the forward closure and the liner to melt the aluminum case unless you have a forward o-ring failure that is allowing that gas to flow out.

The 54-6XL case is long and sliding a motor in with a slightly dirty case or insufficient lubrication, in my mind, can damage that forward o-ring during installation preventing a seal. If that happens and gases flow up past the o-ring they are going to melt the aluminum case and cause the catos that are seen here.

I know greasing the o-ring is insufficient to get it to slide all the way forward in that long case. You have to lubricate the inside of the case, the whole case, or the o-ring won't reach the forward end without sliding some of the way without lubrication.

Again, just my personal opinion, but I think that gluing the forward closure is just a stop gap to help slow or try to prevent gas flow past damaged forward o-rings. Having a well lubricated case so the forward o-ring is installed undamaged and provides a seal is what really prevents the flow of hot gases and catos.

I always make sure I clean my 54-6XL case extremely well. Before I load a motor, I heavily grease the forward o-ring and then spray huge amounts of silicone spray into the case until the whole inside is well wetted and the liquid is dripping out of both ends. Only then do I insert the motor. It slides easily all the way in. The only real resistance is getting the o-ring past the bottom edge and into the case.

Again, all of this is my personal opinion and I have no basis for this other than my experiences with my motors, o-rings, and various catos I've experienced.



How many of you that experienced catos, had stiffness, or difficulty getting the forward closure and o-ring to slide all the way to the end of the motor case? Did you have to push really hard to get the reload to go all the way into the case?

How clean was the case interior?

Were there any nicks, gouges, or imperfections on the bottom edge of the case, that the o-ring has to push past to get into the case, that might have damaged the o-ring?
 
Handeman said:
I've flown a half dozen or more 5, 6, 6XL 54 mm motors and never had an issue. Maybe I'm just lucky, but...

My personal opinion is that the issue may be more about the forward o-ring than anything else. I don't believe you can get enough hot gas flowing between the forward closure and the liner to melt the aluminum case unless you have a forward o-ring failure that is allowing that gas to flow out.

The 54-6XL case is long and sliding a motor in with a slightly dirty case or insufficient lubrication, in my mind, can damage that forward o-ring during installation preventing a seal. If that happens and gases flow up past the o-ring they are going to melt the aluminum case and cause the catos that are seen here.

I know greasing the o-ring is insufficient to get it to slide all the way forward in that long case. You have to lubricate the inside of the case, the whole case, or the o-ring won't reach the forward end without sliding some of the way without lubrication.

Again, just my personal opinion, but I think that gluing the forward closure is just a stop gap to help slow or try to prevent gas flow past damaged forward o-rings. Having a well lubricated case so the forward o-ring is installed undamaged and provides a seal is what really prevents the flow of hot gases and catos.

I always make sure I clean my 54-6XL case extremely well. Before I load a motor, I heavily grease the forward o-ring and then spray huge amounts of silicone spray into the case until the whole inside is well wetted and the liquid is dripping out of both ends. Only then do I insert the motor. It slides easily all the way in. The only real resistance is getting the o-ring past the bottom edge and into the case.

Again, all of this is my personal opinion and I have no basis for this other than my experiences with my motors, o-rings, and various catos I've experienced.



How many of you that experienced catos, had stiffness, or difficulty getting the forward closure and o-ring to slide all the way to the end of the motor case? Did you have to push really hard to get the reload to go all the way into the case?

How clean was the case interior?

Were there any nicks, gouges, or imperfections on the bottom edge of the case, that the o-ring has to push past to get into the case, that might have damaged the o-ring?
Click to expand...
Like you, I have been doing this a long time. I treat my casings just as I treat my guns. After use, they are cleaned and lubed. CTI motor loads get the glue and lube treatment. I remember being told when I first started using CTI motors, that lubing the o-rings was not necessary and gluing the FWD closure and nozzle to the liner was also not necessary. To me, gluing in the FWD closure and nozzle, along with lubing the o-rings are extra steps that help retain gas pressure where it's supposed to be. It's simple physics. I have only had one CTI motor failure and as stated in my last post it was a cato. It was a burn through at the top, just after the FWD closure and it also blew off the aft closure retainer. I don't know what caused the cato and probobly never will. However one thing for sure, cleaning, lubing, and gluing did not prevent the cato from happening.
 
Handeman said:
I've flown a half dozen or more 5, 6, 6XL 54 mm motors and never had an issue. Maybe I'm just lucky, but...

My personal opinion is that the issue may be more about the forward o-ring than anything else. I don't believe you can get enough hot gas flowing between the forward closure and the liner to melt the aluminum case unless you have a forward o-ring failure that is allowing that gas to flow out.

The 54-6XL case is long and sliding a motor in with a slightly dirty case or insufficient lubrication, in my mind, can damage that forward o-ring during installation preventing a seal. If that happens and gases flow up past the o-ring they are going to melt the aluminum case and cause the catos that are seen here.

I know greasing the o-ring is insufficient to get it to slide all the way forward in that long case. You have to lubricate the inside of the case, the whole case, or the o-ring won't reach the forward end without sliding some of the way without lubrication.

Again, just my personal opinion, but I think that gluing the forward closure is just a stop gap to help slow or try to prevent gas flow past damaged forward o-rings. Having a well lubricated case so the forward o-ring is installed undamaged and provides a seal is what really prevents the flow of hot gases and catos.

I always make sure I clean my 54-6XL case extremely well. Before I load a motor, I heavily grease the forward o-ring and then spray huge amounts of silicone spray into the case until the whole inside is well wetted and the liquid is dripping out of both ends. Only then do I insert the motor. It slides easily all the way in. The only real resistance is getting the o-ring past the bottom edge and into the case.

Again, all of this is my personal opinion and I have no basis for this other than my experiences with my motors, o-rings, and various catos I've experienced.



How many of you that experienced catos, had stiffness, or difficulty getting the forward closure and o-ring to slide all the way to the end of the motor case? Did you have to push really hard to get the reload to go all the way into the case?

How clean was the case interior?

Were there any nicks, gouges, or imperfections on the bottom edge of the case, that the o-ring has to push past to get into the case, that might have damaged the o-ring?
Click to expand...
I certainly agree that gluing the closure is a stop-gap measure (literally, I guess).

I also agree that making sure the O-ring is lubricated through the case is a good idea, as is keeping the cases clean.

However, I don't think the problem is related only to a failure of the O-ring. A leak past the O-ring would probably provide a gas path to expose the case to hot gas, and this might explain some failures. But, in the handful of examples that I have looked at, there is no damage to the closure or the case above the O-Ring. The attached pics show this, as do the examples in Posts 154 and 446 (where the problem was noted with double O-rings). I think the gas goes down, which is why I suggest greasing the liner to physically block that path. I believe CTI recommended this in Post 466.

Jim
 

Attachments

  • DSCF0872.JPG
    DSCF0872.JPG
    2.5 MB · Views: 0
  • DSCF0894.JPG
    DSCF0894.JPG
    2.6 MB · Views: 0
Even with a J430 I've hand some the burn thru the liner.

1662953710004.png

... and interestingly where the 2 grain motors have a single case bearing o-ring the 4 grain motors have double o-ring where one is liner bearing.1662954046576.pngMakes one wonder if the failures in the longer motor are because CTI packaged the wrong forward closure.
 
This whole thread is scary. And the warranty service I am hearing from CTI in this thread is, IMO, total garbage. If my reload or casing fails, you the manufacturer should SHIP MY REPLACEMENT TO ME ASAP. Not my dealer. Wait for my dealer to order? I don't care if it cost you a million dollars in Hazmat fees. SHIP IT NOW! TO ME! Not the #@%#@%@ dealer!!! Or get out of the hobby business if you can't design, produce, and sell a product you can stand behind... Wow. What a sad sad state of affairs. I had no idea (and I have 45 CTI loads).

I should add I have never had a claim. All my loads where bought years ago from Performance Hobbies. But does not excuse what I read here. The idea I have to wait until my dealer places an order (like what twice a year? what if it is only once a year?) is assinine. When my case and load are damaged, YOU owe me a replacement ASAP. Not when my dealer decides to make an order.
 
Last edited:
JackC said:
Are the CTI igniters that come with the 54mm motors the same as e-matches we use for altimeter charges (9 volt)?
Click to expand...

Unfortualy not always. For at least a short period in 2018 or 2019 they where shipping at least the J430s with a glob on pyrogen formed around an ematch and no ignition pellet. Despite the issue being well documented CTI denied making the change in production. :(
 
gdjsky01 said:
This whole thread is scary. And the warranty service I am hearing from CTI in this thread is, IMO, total garbage. If my reload or casing fails, you the manufacturer should SHIP MY REPLACEMENT TO ME ASAP. Not my dealer. Wait for my dealer to order? I don't care if it cost you a million dollars in Hazmat fees. SHIP IT NOW! TO ME! Not the #@%#@%@ dealer!!! Or get out of the hobby business if you can't design, produce, and sell a product you can stand behind... Wow. What a sad sad state of affairs. I had no idea (and I have 45 CTI loads).
Click to expand...
It sounds like you need to sell all those reloads to me for $100 and go strictly Aerotech.;)
 
I agree that CTI should be doing the Warranty replacement ASAP, not their dealer. Recently I had a CTI 38mm 6XL casing burn totally through and was surprised to find out that it is the dealers problem, not CTI. Really CTI?? I have been using CTI exclusively for the last 3 years and this is the first problem I have ever had. But very disappointed in CTI for shoving its defects off on a tight funded Dealer
 
racerRobert said:
I agree that CTI should be doing the Warranty replacement ASAP, not their dealer. Recently I had a CTI 38mm 6XL casing burn totally through and was surprised to find out that it is the dealers problem, not CTI. Really CTI?? I have been using CTI exclusively for the last 3 years and this is the first problem I have ever had. But very disappointed in CTI for shoving its defects off on a tight funded Dealer
Click to expand...
Where did you here the dealer is responsible for warranty replacement? My dealer isn't.
 
racerRobert said:
I agree that CTI should be doing the Warranty replacement ASAP, not their dealer. Recently I had a CTI 38mm 6XL casing burn totally through and was surprised to find out that it is the dealers problem, not CTI. Really CTI?? I have been using CTI exclusively for the last 3 years and this is the first problem I have ever had. But very disappointed in CTI for shoving its defects off on a tight funded Dealer
Click to expand...
As I understand it, CTI does cover the cost of the replacement motor and case, but the replacement items are sent to the customer via the dealer. I'm assuming for the same reason (whatever it is) that you can't order from CTI direct.
 
crossfire said:
Where did you here the dealer is responsible for warranty replacement? My dealer isn't.
Click to expand...
Many folks are under the mistaken impression that the dealer is responsible, and it's not entirely their fault for believing this.

Many dealers will, if they have stock of the replacement product in hand and if they have enough volume of sales, go ahead and replace the hardware and reload from their inventory once the customer proves that a warranty claim has been filed.

This, of course, puts the dealer's cash on the line, and they're often waiting a year or more for satisfaction, regardless of manufacturer as many historical accounts will attest. Not sure why it takes that long, but it seems to be more a hit or miss proposition than anything else.....and it seems that common practice is to dispatch warranty claim replacements with the dealer's next order to save everyone some shipping $$.

Never mind the issue that some dealers simply won't or can't afford to do the on field replacement for a variety of reasons. I've seen some rather heated discussions happen both ways.....dealer has the stock but won't 'fill the gap' as it were, and dealers who can't really afford to tie up more money waiting on the motor manufacturer go ahead and put themselves out for the sake of the rocketeer.

At the end of the day, it's the CUSTOMER that should be filling out the warranty claim and the MESS report, not the dealer. Some folks don't know that, and some folks just don't care......they just want someone local to vent at and to make them whole....instantly!
 
Last edited:

Similar threads

ljwilley
Chat GPT giving very interesting answers to questions
Replies
26
Views
1K
cwbullet
cwbullet
the_mell0nator
UTK Rocket Man
Replies
15
Views
845
Hobie1dog
Hobie1dog
R
SystemsGo SETX Build
2
Replies
34
Views
1K
kramer714
kramer714
mago0
5.5 Goblin build for my L1
2
Replies
32
Views
2K
mago0
mago0
MarsLander
Flutter Tools for You.
Replies
11
Views
1K
atestani
atestani

Latest posts

Back
Top