Cesaroni Nozzle Throat Diameters and compatibility

This weekend I tried to help a dealer and a fellow rocket flyer out - the nozzle from a load was missing (not sure why - he may have misplaced it since opening it) and the flyer asked the dealer what other nozzle might work from another Cesaroni load since the dealer was out of that load. If this had been Aerotech the data on Nozzle throat and such would have been on the website but Cesaroni doesn't publish this data.

I emailed Cesaroni but the response was too late to help the flyer. I also inquired about the possibility of releasing a chart of compatible nozzles but they declined saying that they preferred to keep this a dealer only thing and to do it on a case by case basis rather than a chart. Does that make sense? It seems just a bit controlling and out of step with other manufacturers practices.

I responded to the email within a few hours - on a statutory holiday. If that was not fast enough, the dealer could have called me on my cell phone 24/7. They all have my number.

We prefer to have dealers contact us, so we can point out caveats. Certain reloads look like they have similar grains, but they are in fact different and can not just be mixed up.

Jeroen

Jeroen_at_CTI said:

I responded to the email within a few hours - on a statutory holiday. If that was not fast enough, the dealer could have called me on my cell phone 24/7. They all have my number.

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You did reply quickly but it was too late for the flight to take place which wasn't your fault. Not every launch even has a dealer on site and having the data available would help in those cases. We called but I think Ken gave us the office number - and when we realized you were closed I don't think anyone wanted to disturb you on the cell - everybody deserves a day off!

Jeroen_at_CTI said:

We prefer to have dealers contact us, so we can point out caveats. Certain reloads look like they have similar grains, but they are in fact different and can not just be mixed up.

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I'm confused by this. I have not once mentioned grains and swapping out parts other than exactly matched nozzles. I agree that anything other than a directly identical part swap would be incorrect to attempt. However an exactly matched part should be a simple swap. If there are other reasons that I am failing to understand maybe you can contact me offline or state them here. You have my email contact info from this weekend.

Additionally a lot of people want to learn more about how various motors are designed. Knowing the core sizes of grains and the nozzle throats etc is key to that understanding - most other manufacturers make this material available. It would be nice to have this for knowledge sake alone.

UncleVanya said:

This weekend I tried to help a dealer and a fellow rocket flyer out - the nozzle from a load was missing (not sure why - he may have misplaced it since opening it) and the flyer asked the dealer what other nozzle might work from another Cesaroni load since the dealer was out of that load. If this had been Aerotech the data on Nozzle throat and such would have been on the website but Cesaroni doesn't publish this data.

I emailed Cesaroni but the response was too late to help the flyer. I also inquired about the possibility of releasing a chart of compatible nozzles but they declined saying that they preferred to keep this a dealer only thing and to do it on a case by case basis rather than a chart. Does that make sense? It seems just a bit controlling and out of step with other manufacturers practices.

Click to expand...

A reload is certified to perform with the parts in the kit, and a manufacturer keeps track of this. I can understand why CTI doesn't provide this information or replacement parts direct to the consumer.

They don't want folks messing with their motors, and then filing a claim that the motor failed when they decided to change the nozzle to get better performance. :wink: Going through the vendor adds a layer of insurance that it won't happen.

BTW - I didn't see any nozzles being listed or sold on the AT website, and it's not unheard of for a manufacture to change the nozzle size slightly to adjust for batch to batch differences in propellant performance so you can't be sure the nozzle size currently being supplied with a reload is drilled to the proper size for an earlier lot of motors without contacting the manufacturer.

Bob