Pro38 rear closures?

A while back, I picked up a Pro38 starter set from Performance Hobbies. I finally pulled it out of mothballs and realized the kit does not come with any rear closures. Since this is CTI, I had to go to their vendor pages to look for a supplier. But I don't see it on the vendor sites.

Am I missing something? Who sells them?

Thanks for you help.

The motors come with an aft closure molded into the motor. No aft closure is supplied with the hardware because it would do no good.. :rofl:

No reusable closure.... they're part of each Pro-38 reload and include the nozzle. So what you do is, open the package, cut the delay with the DAT, put the delay back in the top, and screw the whole thing into the casing. Quite slick...


Later!

--Coop

Coop said:

No reusable closure.... they're part of each Pro-38 reload and include the nozzle.--Coop

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Ok! Now it makes sense. I'm just now moving on to 38mm after having used 29mm for a while. I was not aware the paradigm changes at 38mm.

The Pro-38 is the only size which uses this method, sadly. I'd like to see it in 24-54, personally...


Later!

--Coop


Sent from my iPad using Rocketry Forum

LW Bercini said:

Ok! Now it makes sense. I'm just now moving on to 38mm after having used 29mm for a while. I was not aware the paradigm changes at 38mm.

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It's unique to CTI 38mm, and really ought to change, because it enables people to retain the reloads without having a case. That leads to setting their rockets on fire...

Also, it costs more. Because the reload has to supply an aft closure for every single reload.

When CTI first started making reloads for the Hobby people the Pro38s were their first motors they made. Once they really caught on their new motors 29mm 54mm 75mm and 98mm had closures that are to be reused.

It's got it's pluses and minuses. It makes the cases cheaper with one less part to purchase. Drawbacks are that unless you are careful you can cross thread the plastic closure and the case can be difficult to remove if you friction fit motors. Because the plastic is not as strong there are some propellant/length combinations that are not possible.

CarVac said:

It's unique to CTI 38mm, and really ought to change, because it enables people to retain the reloads without having a case. That leads to setting their rockets on fire...

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Pretty sure that's called natural selection.

GRIFFIN said:

Pretty sure that's called natural selection.

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That's my personal opinion as well, honestly, but I'd rather they be scared off by difficult assembly than by lighting their rocket on fire.

I've had some 38mm 6G and 6XL loads that were very difficult to seat, even with grease, and I'm hesitant to try to force the threads since they're plastic. Bad things happen when you cross-thread plastic threads into metal, then heat it up and add pressure to the mix. I personally would not hesitate to spend the extra $30 or so for a metal rear closure. Every rocket that I have that has a 38mm motor mount is worth a lot more than that.

I think it is time to change the pro38 to a new case with a metal closure.

Or one might just fly Aerotech 38mm hardware.

cwbullet said:

I think it is time to change the pro38 to a new case with a metal closure.

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I was told by Dr. J that they would have to re-certify EVERY motor if the hardware changed. Don't count that happining any time soon.

GRIFFIN said:

I was told by Dr. J that they would have to re-certify EVERY motor if the hardware changed. Don't count that happining any time soon.

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I wonder if they could make metal closures for the existing cases, and just phase in new reloads that require a closure, discontinuing the old ones, until eventually they all require the closures.

Jimmy F. said:

Or one might just fly Aerotech 38mm hardware.

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Then you would have to fly Aerotech motors :tongue:

CarVac said:

I wonder if they could make metal closures for the existing cases, and just phase in new reloads that require a closure, discontinuing the old ones, until eventually they all require the closures.

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I can see having 2 different "styles" of motors a bigger problem.

I have never had a proplem with the closures on the mootrs. I have had issues with a failed load, and the case was replaced before I left that launch (see post 17.....you will be faced with a different challenge)

The only benefit I can see, would be having some long burns in the 38 range. The plastic closures just cant handle the heat soak.

forget it. Not worth it.

GRIFFIN said:

Then you would have to fly Aerotech motors :tongue:

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Settle down fan boy.

chadrog said:

Settle down fan boy.

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Hey, aren't you on some tropical vacation or something?


LOL!! Chad, get bit by the dog once or twice, and you learn....the dog doesn't like you.

Everyone has different experiences. Mine was not a pleasurable one. I have bins full of both brands, I just feel one has a better customer service. This is from real experience, not from jumping on any sort of bandwagon or a "hey my buddy said.....". But yes, I will admit, the customer service is second to none and that does create a bit of a "fan boy" out of me.

Maybe the shift into single use motors will be a good thing. The end result will 100% guarantee that they will never have to replace hardware again......just say'n

GRIFFIN said:

Hey, aren't you on some tropical vacation or something?


LOL!! Chad, get bit by the dog once or twice, and you learn....the dog doesn't like you.

Everyone has different experiences. Mine was not a pleasurable one. I have bins full of both brands, I just feel one has a better customer service. This is from real experience, not from jumping on any sort of bandwagon or a "hey my buddy said.....". But yes, I will admit, the customer service is second to none and that does create a bit of a "fan boy" out of me.

Maybe the shift into single use motors will be a good thing. The end result will 100% guarantee that they will never have to replace hardware again......just say'n

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Not yet, Mexico on Sunday - yay. That new SU L has me very curious, looks like a good one for the 3" Darkstar.

GRIFFIN said:

I was told by Dr. J that they would have to re-certify EVERY motor if the hardware changed. Don't count that happining any time soon.

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That is what I figured. Hopefully the economy improves to provide income to add fuel for future development.

I am a big Aerotech fan, I have multiples of all their hardware up to and including 54mm. I have no issues with assembly and have never had a cato. Yes, I have seen alot, I have been lucky I guess. I also love the CTI Skid loads and the ease of assembly of the CTI loads just can't be beat. Although I have had Pro38 6XL J520 cato on me destroying my rocket. I will not discount user error, I will not guarantee I didn't cross thread the closure. Anyway, I am a big fan of both sides, the Pro38 ain't broke, no need to fix it!!

jimzcatz said:

I am a big Aerotech fan, I have multiples of all their hardware up to and including 54mm. I have no issues with assembly and have never had a cato. Yes, I have seen alot, I have been lucky I guess. I also love the CTI Skid loads and the ease of assembly of the CTI loads just can't be beat. Although I have had Pro38 6XL J520 cato on me destroying my rocket. I will not discount user error, I will not guarantee I didn't cross thread the closure. Anyway, I am a big fan of both sides, the Pro38 ain't broke, no need to fix it!!

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It ain't broke, but it could be cheaper.

jimzcatz said:

I am a big Aerotech fan, I have multiples of all their hardware up to and including 54mm. I have no issues with assembly and have never had a cato. Yes, I have seen alot, I have been lucky I guess. I also love the CTI Skid loads and the ease of assembly of the CTI loads just can't be beat. Although I have had Pro38 6XL J520 cato on me destroying my rocket. I will not discount user error, I will not guarantee I didn't cross thread the closure. Anyway, I am a big fan of both sides, the Pro38 ain't broke, no need to fix it!!

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I fly both Aerotech and CTI, probably 75% of the time using Aerotech. Up until last Saturday I've never had a failure of either one. I launched my THOR clone on a 38mm CTI 6XL J530 Imax. It was my first time using an Imax reload. Great looking flight, everything looked great until I got home and pulled the motor out of the back of the rocket. About an inch past the Aeropack 54/38 adapter, the casing had an inch long burn through that unfortunately cooked the inside of the motor tube. I think I can continue to fly this rocket using the adapter, but the damage will prevent using a 54mm motor in it again. This experience has soured me a bit on CTI, so it will probably be 90% Aerotech from here out. Which is a shame, because I really love the 54mm CTI J760W motor.

The CTI 38mm 6G and 6XL loads seem to regularly burn through the liner, ususally near the nozzle end. I always grease the liner slightly before putting it into the casing, so that when it burns through it won't stick to the casing. That being said, I've never had one fail, but I still have my concerns about the plastic end closures.

An argument can be made, of course, that if you need to use 38mm 6XL loads to get you to where you want to be, then you should be flying 54mm...

cerving said:

I've had some 38mm 6G and 6XL loads that were very difficult to seat, even with grease, and I'm hesitant to try to force the threads since they're plastic. Bad things happen when you cross-thread plastic threads into metal, then heat it up and add pressure to the mix. I personally would not hesitate to spend the extra $30 or so for a metal rear closure. Every rocket that I have that has a 38mm motor mount is worth a lot more than that.

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I'll second that. I have been quite frustrated at times getting the 38mm loads seated properly (I also liberally grease). No disasters yet, but I feel it is only a matter of time.

I remove the nozzle and push the liner/grains/forward closure into place using a spacer.[after wiping the bottom inside of case with grease].
Then the nozzle screws easily into case, not having to push anything in front of it.
No more worries about cross threading.

neond7 said:

I launched my THOR clone on a 38mm CTI 6XL J530 Imax.

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I believe there was a recall on that motor due to defective liners, you might want to check on that.