CTI Cesaroni Technology

Jeroen_at_CTI said:

CTI is releasing the next generation of Pro75 Hardware - Generation 2 (Gen.2)!

...Gen.2 hardware will be available soon.

View attachment 247744
Gen.2 retaining rings (left: forward; right: aft).

Jeroen

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I hope 'soon' means pre-orders start tomorrow !

Kenny

Jeroen_at_CTI said:

CTI is releasing the next generation of Pro75 Hardware - Generation 2 (Gen.2)!

New features:

1. The thrust ring was moved from the case and integrated with the aft retaining ring. The forward retaining ring can also be installed on the aft end for a flush configuration.
2. Reduced thread pitch size to increase the strength of the case ends and also increase the burst pressure of the hardware while still maintaining an axial failure mode.

Retaining rings of Gen.2 hardware will not be compatible with existing hardware, but the forward closure and nozzle housing remain the same. CTI will continue to stock existing retaining rings to service customers with Gen.1 hardware.

Gen.2 hardware will be available soon.

View attachment 247744
Gen.2 retaining rings (left: forward; right: aft).

Jeroen

Click to expand...

Any particular reason for removing the thrust ring from the case and integrating it into the closure? Just for flush configuration purposes?

MarkH said:

Any particular reason for removing the thrust ring from the case and integrating it into the closure? Just for flush configuration purposes?

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I think the key is in point #2. A flyer at BALLS this year doing a sub-minimum diameter flight managed to snap the forward end off the 75mm case at the threads.

matthew said:

I think the key is in point #2. A flyer at BALLS this year doing a sub-minimum diameter flight managed to snap the forward end off the 75mm case at the threads.

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What does sub-minimum diameter mean?

MarkH said:

Any particular reason for removing the thrust ring from the case and integrating it into the closure? Just for flush configuration purposes?

Click to expand...

More flexibility for the user (i.e. flush configuration) as well as ease of manufacturing.

Jeroen.

Any chance the new thread pitch is the same as Brand A's ?

Eric

3stoogesrocketry said:

Any chance the new thread pitch is the same as Brand A's ?
Eric

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Maybe - by chance. It was not designed that way. The thread profile will be different. We use ACME threads.

Jeroen

Ok thanks Jeroen , I forgot you used ACME threads .

Eric

DavieRockets said:

What does sub-minimum diameter mean?

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Maybe flying case with the retaining ring also retaining the front half of the motor?

DavieRockets said:

What does sub-minimum diameter mean?

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Yes, basically a flying case without a supporting airframe. Fin can is attached direct to case, with coupler size forward airframe part of rocket attached by bolt to threaded forward closure. A lot of stress is on the forward closure and the case threads.

matthew said:

Yes, basically a flying case without a supporting airframe. Fin can is attached direct to case, with coupler size forward airframe part of rocket attached by bolt to threaded forward closure. A lot of stress is on the forward closure and the case threads.

Click to expand...

I can vouch for the 98 being strong enough, though. Coning at M4 didn't do anything to the case (though hitting the ground did). We never considered that failure mode when designing Bare Necessities, though.

Weeeeeeeeeeeeeeeeeeeell... regardless of whether this is relevant to the development of this topic or not... I got this lil sweet package in the mail the other day and it makes me smile!

Jeroen_at_CTI said:

CTI is releasing the next generation of Pro75 Hardware - Generation 2 (Gen.2)!

New features:

1. The thrust ring was moved from the case and integrated with the aft retaining ring. The forward retaining ring can also be installed on the aft end for a flush configuration.
2. Reduced thread pitch size to increase the strength of the case ends and also increase the burst pressure of the hardware while still maintaining an axial failure mode.

Retaining rings of Gen.2 hardware will not be compatible with existing hardware, but the forward closure and nozzle housing remain the same. CTI will continue to stock existing retaining rings to service customers with Gen.1 hardware.

Gen.2 hardware will be available soon.

View attachment 247744
Gen.2 retaining rings (left: forward; right: aft).

Jeroen

Click to expand...

Is there a new style 75mm tailcone style aft retaining ring?
I was able to puchase a 75mm Gen 2 4G motor set and spacers at NARCON thanks to Bay Area Rocketry and a fellow named Chris. (Didn't meet Chris, thank you!)
I'd like to get a few more pieces and just wondered about the tail cone.

Does anyone know the answer to this? ^^^^

I got an answer to my question about the new tailcone. There is a new tailcone coming to match the Gen 2 hardware.

Any cert sessions pending?

I was hoping for a 24-6gxl with a 24mm h motor.

Seriously, they make so many motors already...

+1 ^^^^^

Yes the current offering remains deliciously overwhelming, Mark.

gizza2 said:

Any cert sessions pending?

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Not scheduled yet, but working towards one at end of May.

markkoelsch said:

I was hoping for a 24-6gxl with a 24mm h motor.

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We welcome all suggestions.

Jeroen

A good purple propellant.

More long-burn skids like the J145 in different diameters, esp 38 and 29...smokies too.

I have found the the mellow is a tad undercooked for me personally, as I always find myself struggling to get a design I want that will have sufficient velocity off the rod. That's partially a product of my preferences for rocket type, but I often wish just a little of that burn time could be traded off for a little more kick and a yellow flame.

It would be wonderful if, in the long term, the 38s could have a version with a regular, separate aft closure. I've seen melted plastic threads and propellent gasses leaking through on the J530 iMax.

It would also be cool to have a better minimum diameter retention option than the Aeropack adapter - one capable of serving as an attachment point for the recovery laundry.

Anyway, you asked. Keep up the good work

wfcook said:

I have found the the mellow is a tad undercooked for me personally, as I always find myself struggling to get a design I want that will have sufficient velocity off the rod. That's partially a product of my preferences for rocket type, but I often wish just a little of that burn time could be traded off for a little more kick and a yellow flame.

Click to expand...

The Mellow Yellow motors are great for clusters. I like having a propellant that is really designed for clusters.

JMZawodny said:

The Mellow Yellow motors are great for clusters. I like having a propellant that is really designed for clusters.

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Even with clusters, at least the canted ones I favor, I find that just a little bit more thrust would bee very helpful. Again, this is a product of my personal preference in rockets, but that's what I am seeing.

How about a Mellow in the center with 2 or three surrounding motors? Clustered Skidmarks would be cool...

cerving said:

How about a Mellow in the center with 2 or three surrounding motors? Clustered Skidmarks would be cool...

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Specifically, I am into canted clusters. A motor in the middle spoils the effect.

wfcook said:

Specifically, I am into canted clusters. A motor in the middle spoils the effect.

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So, how about a 3-way canted cluster of mellow? 3 J150s should be enough to lift about a 50 lb rocket plus 6.5s of burn time = fun!

Nate

nute said:

So, how about a 3-way canted cluster of mellow? 3 J150s should be enough to lift about a 50 lb rocket plus 6.5s of burn time = fun!

Nate

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I don't know how you figure that, but if I'm the RSO, I wil send you back to your table redo the math

That is like 4.5:1 off of the pad. That sounds a bit iffy to me.

Yes I suppose my math was a bit off. Initial thrust= 77lbs x 3= 231/5= 46. Ok, so 40 lbs and a long rail would be a better idea.

Nate

the 77 is not even 1/10 seconde it drop fast to 56 lbs of trust. ( beside the formula is for compute with the average not the maximum trust ) . Also it's a cluster, 1 or 2 motors may nor start, this will put this 50 lbs rocket in dangerous position.

so 150 x 3 = 450 N / 4.45 = 101 / 50 = 2 at 2 we are far from the 3 of Tripoli and even more far than 5 ....

from Tripoli

G. Weight Limits
1. The maximum lift-off weight of a rocket shall not exceed one-third (1/3) of the average thrust on the motor(s) intended to be ignited at launch.

nute said:

So, how about a 3-way canted cluster of mellow? 3 J150s should be enough to lift about a 50 lb rocket plus 6.5s of burn time = fun!

Nate

Click to expand...

I think not. That is only 450 newtons of thrust average. More like 15-20 pounds max assuming mild winds.

Ok, I'm sorry, I was just quickly posting something- I didn't look closely at the thrustcurves. Anyway, yes it does look like a lighter rocket would be in order. My bad.

Nate