CTI Discussion Thread

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While I'm glad CTI refunded the J-360 and the case, I'm disappointed that they didn't refund the closure too. I've already gone through one Dremel wire wheel trying to get the molten aluminum off...

20220402_134911.jpg20220402_135027.jpg20220402_135826.jpg
 
Cesaroni Technology said:
CTI only recommends using 2 grain spacers in reloads.
Click to expand...
Ok so the XL counts as one of your two spacers. But just to confirm you can use two regular spacers in a 98mm 6G case to fly 4G reloads correct? I was wondering because in the 38mm size it says you can use two regular spacers in combination with an XL spacer.

Also what is the reason for the recommended limit of 2?
 
I witnessed a disappointing flight this past weekend. An L2 candidate prepared the delay grain of a Pro54 2 grain Smoky Sam motor. It was a J270-16. His simulation suggested a 10 second delay would be good.
I watched the candidate closely as he drilled the delay 6/32” deep. His hands were clean and he didn’t touch the face of the grain, so no chance that it was contaminated. I’ve been flying CTI motors since Ross announced availability of the Pro38 motors. There was nothing I felt this candidate did wrong, in any way!
The shortened delay burned for 18 seconds before the ejection charge went off. Timing was verified on two different videos taken with two different cellphones.
Of course that caused a large zipper and failed L2 attempt.
For years CTI set the standard for quality and consistency. They sure don’t anymore. I’m afraid to recommend them anymore.
 
Steve Shannon said:
I witnessed a disappointing flight this past weekend. An L2 candidate prepared the delay grain of a Pro54 2 grain Smoky Sam motor. It was a J270-16. His simulation suggested a 10 second delay would be good.
I watched the candidate closely as he drilled the delay 6/32” deep. His hands were clean and he didn’t touch the face of the grain, so no chance that it was contaminated. I’ve been flying CTI motors since Ross announced availability of the Pro38 motors. There was nothing I felt this candidate did wrong, in any way!
The shortened delay burned for 18 seconds before the ejection charge went off. Timing was verified on two different videos taken with two different cellphones.
Of course that caused a large zipper and failed L2 attempt.
For years CTI set the standard for quality and consistency. They sure don’t anymore. I’m afraid to recommend them anymore.
Click to expand...
Between the 38mm Fwd closure debacle, the initiator pellet issues ad infinitum, and the acknowledged 54mm motor issues (longs with fwd burn through, shorts with aft burn through), it's pretty hard to recommend much of CTIs catalog these days.

But hey, at least they seem to have a near limitless supply of 29mm F120Vmax motors still using grains with a 2015 casting date.
 
rfjustin said:
Come on CTI, stick a Jr. Project Manager on this issue, apply the 5 why's and and get the root cause of the 54 burn throughs addressed already!
https://kanbanize.com/lean-management/improvement/5-whys-analysis-tool
Click to expand...
Note that it's been 1 year almost to the day that CTI most recently acknowledged the issue on this forum. The actual first acknowledgement occurred well before that, with threads about it starting back around 2018 with some noting the issue arising as far back as 2014!!! The fact that it's infected the 38mm line post the 2016 forward closure issue hasn't gone unnoticed, either!

Post 543

DarthMuffin said:
A couple of questions for CTI:

1) Status of the 54mm forward closure improvements?
Click to expand...
Response from CTI:

Thanks for your inquiry.
1) We've had some delays and are currently upgrading our thrust stands and data capture programs, hopefully done by the new year and have new motors certified by spring, possibly also with a new forward closure for the P54's

But have been well aware of it before that

Post 460

Response from CTI:

We have been looking into the P54 failures, and testing some new ideas to hopefully fix the problem in the near future. Unfortunately we've been very busy and getting results is taking longer than expected.
As a note we have never instructed customers to glue the forward closure in place, although it seems to help it doesn't always work. Sealing the forward closure to the liner causes the liner to take the pressure from the motor, the liners aren't designed to hold that much pressure. In fact the original design had no small oring between the closure and liner, so that the gasses from inside the liner could egress between the liner and forward closure. I still think this is the key to the problem, but we need to test some more to come to a conclusion.
Our thanks to the rocketry community for all their patience and support of our products.

Bob.
 
Last edited:
Steve Shannon said:
I witnessed a disappointing flight this past weekend. An L2 candidate prepared the delay grain of a Pro54 2 grain Smoky Sam motor. It was a J270-16. His simulation suggested a 10 second delay would be good.
I watched the candidate closely as he drilled the delay 6/32” deep. His hands were clean and he didn’t touch the face of the grain, so no chance that it was contaminated. I’ve been flying CTI motors since Ross announced availability of the Pro38 motors. There was nothing I felt this candidate did wrong, in any way!
The shortened delay burned for 18 seconds before the ejection charge went off. Timing was verified on two different videos taken with two different cellphones.
Of course that caused a large zipper and failed L2 attempt.
For years CTI set the standard for quality and consistency. They sure don’t anymore. I’m afraid to recommend them anymore.
Click to expand...

At least it didn't CATO!
 
jmasterj said:
At least it didn't CATO!
Click to expand...
There is that! 🙂

I still will continue to fly CTI motors. I’m usually hosting a launch, acting as RSO, and answering questions, so time is limited. I love building Aerotech or Loki motors, but when I am challenged for time it’s very satisfying to drill a delay and pop a Pro29 into a small motor deployment rocket. I’m just feeling much less confident than I used to and I absolutely hate to recommend something to someone and have them feel let down because their rocket becomes damaged through no fault of their own.
 
Banzai88 said:
Between the 38mm Fwd closure debacle, the initiator pellet issues ad infinitum, and the acknowledged 54mm motor issues (longs with fwd burn through, shorts with aft burn through), it's pretty hard to recommend much of CTIs catalog these days.

But hey, at least they seem to have a near limitless supply of 29mm F120Vmax motors still using grains with a 2015 casting date.
Click to expand...
I saw that Apogee was expecting to get some more and I came here to investigate. I hadn’t heard of their remaining stock before so you can understand my WTF Meter being pegged.
 
Banzai88 said:
But hey, at least they seem to have a near limitless supply of 29mm F120Vmax motors still using grains with a 2015 casting date.
Click to expand...

So I says to myself - "what the heck is this guy talking about?" Then I checked my stock - I have 2 F120s and both are dated March 15, 2016 from an order I got last year. 5 year old stock.
Then I says - OH, OK! :)
 
I wonder if it would be possible for CTI to repackage the F120 reloads that they obviously have somewhere into H410 reloads. I have a few waiting for the right rocket, but I would love to have more.
 
Lord Rory Gin said:
So I says to myself - "what the heck is this guy talking about?" Then I checked my stock - I have 2 F120s and both are dated March 15, 2016 from an order I got last year. 5 year old stock.
Then I says - OH, OK! :)
Click to expand...
I bought a half dozen from Tim/Wildman at Red Glare this spring, and another dozen from Ken/Performance Hobbies about 2 weeks later!

Both guys said that they can get plenty more for the foreseeable future!
 
Banzai88 said:
I bought a half dozen from Tim/Wildman at Red Glare this spring, and another dozen from Ken/Performance Hobbies about 2 weeks later!

Both guys said that they can get plenty more for the foreseeable future!
Click to expand...
That's what happened to them.
I bought a few Saturday. Went back Sunday for more and he was sold out. lol
 
gdjsky01 said:
I have a few Quickburst starters. But IIRC they are a pain to use. You have to peel off the outside ???
I think I have my answer. I can use an e-match like the MJGs or a slim 'normal' starter. Thanks. Unless CTI
chimes it, or someone tells me they had a bad experience, I'll go with that. Thank you
Click to expand...
I’ve used Quickburst igniters for over 15 years and I’ve never peeled off the plastic. They work perfectly fine as is.
 
Last edited:
Steve Shannon said:
I witnessed a disappointing flight this past weekend. An L2 candidate prepared the delay grain of a Pro54 2 grain Smoky Sam motor. It was a J270-16. His simulation suggested a 10 second delay would be good.
I watched the candidate closely as he drilled the delay 6/32” deep. His hands were clean and he didn’t touch the face of the grain, so no chance that it was contaminated. I’ve been flying CTI motors since Ross announced availability of the Pro38 motors. There was nothing I felt this candidate did wrong, in any way!
The shortened delay burned for 18 seconds before the ejection charge went off. Timing was verified on two different videos taken with two different cellphones.
Of course that caused a large zipper and failed L2 attempt.
For years CTI set the standard for quality and consistency. They sure don’t anymore. I’m afraid to recommend them anymore.
Click to expand...
At a recent launch I sent my Minnie-Magg up on a 29mm CTI G131-14A Smokey Sam. I drilled the delay out the maximum 9 seconds with the tool and made sure to blow out all the loose material. I used the tool twice to make sure I was deep enough because this was the smallest motor I had tried in this rocket. I experienced the same thing, a seemingly longer delay than expected, the charge went off about 10 feet off the ground, and unfortunately the rocket went right through someone's tent. Luckily, no-one was injured.
The rocket was undamaged and I flew it again later that day on a CTI H163-14A White Thunder with the same drilled delay with a normal deployment near apogee. Being new I thought I did something wrong [too small motor] on the Smokey Sam flight but now that I read this I wonder. Anyway, be careful if you are using this particular propellant.
 
Last edited:
Rschub said:
At a recent launch I sent my Minnie-Magg up on a 29mm CTI G131-14A Smokey Sam. I drilled the delay out the maximum 9 seconds with the tool and made sure to blow out all the loose material. I used the tool twice to make sure I was deep enough because this was the smallest motor I had tried in this rocket. I experienced the same thing, a seemingly longer delay than expected, the charge went off about 10 feet off the ground, and unfortunately the rocket went right through someone's tent. Luckily, no-one was injured.
The rocket was undamaged and I flew it again later that day on a CTI H163-14A White Thunder with the same drilled delay with a normal deployment near apogee. Being new I thought I did something wrong [too small motor] on the Smokey Sam flight but now that I read this I wonder. Anyway, be careful if you are using this particular propellant.
Click to expand...
Backup electronic deployment or flying it in a cluster may be safer.
 
SolarYellow said:
What is the OD of the rear closure knurl/knob on a Pro38 motor? Just wondering if it would stick out past an LOC 38mm tube's outer wall (1.625 inch) or a really close to that 42mm.
Click to expand...
It would be nice if CTI put that dimension on the drawing.
http://www.pro38.com/pdfs/Pro38_dimensions.pdf
On a PRO29 case is 1.125, knurl is 1.253 or 0.128" larger than case.
The Pro38 is probably close to the same increase.
So 1.5 + 0.128 = 1.628"
 
Last edited:
waltr said:
It would be nice if CTI put that dimension on the drawing.
http://www.pro38.com/pdfs/Pro38_dimensions.pdf
On a PRO29 case is 1.125, knurl is 1.253 or 0.128" larger than case.
The Pro38 is probably close to the same increase.
So 1.5 + 0.128 = 1.628"
Click to expand...

It's not on the hardware drawing because it's not hardware, it's a plastic part of the reload. I don't have one I want to open at the moment, but I think it probably extends farther than the Pro29 one.
 
SolarYellow said:
What is the OD of the rear closure knurl/knob on a Pro38 motor? Just wondering if it would stick out past an LOC 38mm tube's outer wall (1.625 inch) or a really close to that 42mm.
Click to expand...
41mm (1.614" @ 25.4mm/") and is 9.5mm (0.374") thick. I always have a used closure handy for those "what if" moments.
Cheers,
Mark
 
Thanks for taking the time to dig it out and measure.

I also finally got an email from ProX Support (Thanks to CTI, too):
The diameter of the shoulder is 1.625". As long as your airframe isn't more than 0.0625" in wall thickness it shouldn't protrude from the airframe.
Click to expand...

And yeah on the spares. I have a list of used motors and parts to pull out of trash at the next launch I go to in order to have on hand for spares for mockup, etc.
 
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