CTI Discussion Thread

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Philip Tiberius D.

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Mike,
Every motor company has occasional problems. I’ve used CTI since they first came out with the Pro38s. By and large they have been absolutely excellent. When there is a problem you see a flurry of activity online until there’s some resolution but that shouldn’t lead you to believe that all CTI products have problems or that their competition is perfect. I won’t hesitate to use CTI products, but I probably will avoid the 5, 6, and 6xl reloads in 38 and 54 mm sizes until CTI issues some kind of guidance.
Is there a thread on the CTI 38/54 5/6/6XL concerns or can you give a Readers Digest version here. Might have to rethink some AirFest launches….
 

timbucktoo

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Is there a thread on the CTI 38/54 5/6/6XL concerns or can you give a Readers Digest version here. Might have to rethink some AirFest launches….
Here is a discussion thread on some failures:
 

Philip Tiberius D.

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Here is a discussion thread on some failures:
Thanks… on it like a bum on a bologna sandwich
 

Mike Haberer

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Mike,
Every motor company has occasional problems. I’ve used CTI since they first came out with the Pro38s. By and large they have been absolutely excellent. When there is a problem you see a flurry of activity online until there’s some resolution but that shouldn’t lead you to believe that all CTI products have problems or that their competition is perfect. I won’t hesitate to use CTI products, but I probably will avoid the 5, 6, and 6xl reloads in 38 and 54 mm sizes until CTI issues some kind of guidance.
I suppose you are right, but I see a lot more CTI issues posted than Aerotech. It's anecdotal, but noticeable. Considering I've been seeing these forward closure issues and the debates about them for quite a while, the silence from CTI on the issues noted is disturbing.
 

Wayco

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I suppose you are right, but I see a lot more CTI issues posted than Aerotech. It's anecdotal, but noticeable. Considering I've been seeing these forward closure issues and the debates about them for quite a while, the silence from CTI on the issues noted is disturbing.
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.
First of all, let me make it clear that I'm a big Aerotech fan, probably 80% of my flying is done on AT motors. I also fly everything else, with CTI being right up there with research loads my wife Sharon and I make. I've flown a few LOKI loads, plenty of Estes black powder and a few Quest.
I just data mined my launch log from 2017 to current and found that I have flown 8 38mm CTI 6XL J520's, 5 38mm CTI 4 grain I285's and a smattering of other CTI 38's with no issues. During that time I also flew 16 54mm CTI 6XL's either L935's. L640's or K815's. 10 6 grain CTI 54's and 8 5 grain CTI 54's. Of those, I have had three 6XL casings and one 6 grain 54mm casing replaced by vendors.
I glue the forward plug to the top grain/liner as per Jim Jarvis, and use silicon spray lubricant generously in the casings. Two of the 6XL casings were bubbled before I started gluing them, and one after, which might have been from cheap epoxy.
 

cwbullet

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Would these be the long burn 6 grain or Grain XL motors?
Saw these 2 cases on guys tables on Friday at XPRS. Neither of them were aware of any possible CTI issues.

Tony
 

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The one with the rear closure issue was a 6xl K300 the other 6g..unknown load.

Tony
I have launched 5-6 of these loads and had 2 CATOs or failures and one slightly bulge (Burnthrough?). It is my favorite for my Applewhite saucer.
 

JimJarvis50

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Saw these 2 cases on guys tables on Friday at XPRS. Neither of them were aware of any possible CTI issues.

Tony
Tony,

If you have the opportunity, it might be helpful to know if they greased their liners or not.

Jim
 

Cameron Anderson

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Prepping for BALLS today and I finally cleaned my CTI 38mm 6 grain case from LDRS. This is the case's 5th or 6th flight. Motor was a J425 blue. Rocket performance was as predicted with no unusual smoke or flight characteristics.
I used light lithium grease on the forward closure and aft closure o-rings. I also used light grease just above the case threads to help with assembly.
I always have some liner burn through with CTI 38s but never to this extend before. And the burn through happened right where case bulging occurs. There was no bulging or erosion on the inside of the case.
 

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tfish

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Tony,

If you have the opportunity, it might be helpful to know if they greased their liners or not.

Jim
The one with the rear closure issue. K300. No grease or spray..not the boat tail closure.
The bulged case. K300 other info unknown

Tony
 

T34zac

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Saw these 2 cases on guys tables on Friday at XPRS. Neither of them were aware of any possible CTI issues.

Tony
I talked to the owner of the one with the bulged front end. He didn’t glue the closure or grease the liner.
 

crossfire

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Prepping for BALLS today and I finally cleaned my CTI 38mm 6 grain case from LDRS. This is the case's 5th or 6th flight. Motor was a J425 blue. Rocket performance was as predicted with no unusual smoke or flight characteristics.
I used light lithium grease on the forward closure and aft closure o-rings. I also used light grease just above the case threads to help with assembly.
I always have some liner burn through with CTI 38s but never to this extend before. And the burn through happened right where case bulging occurs. There was no bulging or erosion on the inside of the case.
I have seen that kind of liner melt for years with CTI 38s most of the melt is done after burn out. The liner did its job durning motor burn.
 

JimJarvis50

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The one with the rear closure issue. K300. No grease or spray..not the boat tail closure.
The bulged case. K300 other info unknown

Tony
I'm confused. Both pics look like forward closure issues?

Jim
 

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Hi CTI,

I've had a lot of fun record hunting with your I216 and G150. Thanks a ton for those motors. Is there any chance for a near-full-G Pro24-6G in Imax? It sure would be great to have some more Ns and less average thrust than the G150.

Thanks!
The Pro29 6G IM is in the works, as well as other motors, but currently my time is spent on production.
We're currently looking for a couple of propellant techs, then I can start testing again.
 

GrouchoDuke

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The Pro29 6G IM is in the works, as well as other motors, but currently my time is spent on production.
We're currently looking for a couple of propellant techs, then I can start testing again.
29 6G IM would be fun too. The I224 was good enough for the I record a few years ago. If you need someone to fly that 29, sign me up.

I’d sure love a 24 too.

Thanks
 

Cesaroni Technology

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29 6G IM would be fun too. The I224 was good enough for the I record a few years ago. If you need someone to fly that 29, sign me up.

I’d sure love a 24 too.

Thanks
Sorry, I meant the P24 6G is in the works. The P29 we're working on is the XL.
 

paulfecht

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I see some mention of 54mm reloads and CATOs ...... are there known issues with the 75mm CTI reloads. Curious as that's what I'm up to next weekend at NCR's Oktoberfest.
 

rokit

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I'm confused. Both pics look like forward closure issues?

Jim
I was set up next to the owner of the 2nd, which was a K300. If you look at the bottom end, you can just make out parts of a couple of the threads. If you were able to rotate the casing 90 degrees, you would see where the casing was burned through just above the aft closure.
 

rokit

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P.S. Even with the damage the rocket went over 19K', good for first place in the XPRS K altitude contest.
 

OZRoc

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Some people have reported liners not fitting correctly recently, you might want to check that in advance.
+1 on this. Check fit your liners in the casing before going to the launch. Make sure they slide all the way in. DAMHIK.
Cheers
 
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