Availability of CTI Larger Motors

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BackSeatBryce

BackSeatBryce

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Good morning, everyone.
I took a few years off from the hobby, but I just came back in time to fly at XPRS in 2018. What I learned there was that vendors don't really have any 38mm or 54mm CTI reloads at this time and don't foresee getting a steady supply any time soon (at least this was what the vendors there told me). I'm starting to think about a L3 project, and I'm debating going Aerotech or CTI 75mm or 98mm, but what I'm wondering is whether there are any CTI reloads available for those sizes or whether supply is really small in those sizes as well. Does anyone have any knowledge of CTI reload availability in 75mm or 98mm?

Thanks,
Bryce
 
Contact Wild Man, CS Rocketry, AMW-ProX and ask. They will tell you what they have, and what they know.

CTI's plant suffered an explosion and fire nearly two years ago, and they have never quite recovered.

Also, consider Loki motors. Incredible punch off the pad, and fun to fly. Their hardware can also be used for EX, should you go in that direction.
 
AMW has 75 mm CTI reloads in stock, I just ordered some a couple of days ago.

If you get 75 mm CTI hardware for your L3 then you can use either CTI or Aerotech reloads. But be aware that if you use Aerotech reloads in CTI hardware, you need to buy an Aerotech forward seal disk and for some reason they are hard to find. I got one from CS Rocketry but I don't know if he has any more.
 
AMW-ProX is showing a number of CTI M-class motors in stock. Some types are not listed as in stock and say to call.
 
Thanks everyone for the replies. I didn't realize that there were so many motors that could be used in other vendor's hardware. I need to do some more research on all this before I commit one way or another. Is there a big difference in ease of motor prep between the different vendors at larger motor sizes (75mm and 98mm)? I have used CTI exclusively up to this point (38mm and 54mm), and I love how easy it is to prep those motors. I built my first Aerotech motor this past year (38mm) and it was a real chore. Is there a big difference at the larger motor sizes?
 
BackSeatBryce said:
Is there a big difference in ease of motor prep between the different vendors at larger motor sizes (75mm and 98mm)? I have used CTI exclusively up to this point (38mm and 54mm), and I love how easy it is to prep those motors. I built my first Aerotech motor this past year (38mm) and it was a real chore. Is there a big difference at the larger motor sizes?
Click to expand...

Once you hit 75mm, they all require similar effort. It is definitely a change from the 38 and 54 with CTI. You'll have a liner into which you'll have to place the individual propellant grains with O-ring spacers. You'll have to piece together the delay grain and O-rings. You'll have forward and aft closures that will need to have O-rings added and then screw those onto the casing and tighten them down appropriately. In the CTI line there is no more black powder pellet in the top grain (like the 24- 54mm motors) and you now get a big fat ignitor to use. They're still pretty reliable - I've only had one ignition failure in my 75mm CTI flights and it was because the ignitor spit out.
 
farsidius said:
Once you hit 75mm, they all require similar effort. It is definitely a change from the 38 and 54 with CTI. You'll have a liner into which you'll have to place the individual propellant grains with O-ring spacers. You'll have to piece together the delay grain and O-rings. You'll have forward and aft closures that will need to have O-rings added and then screw those onto the casing and tighten them down appropriately. In the CTI line there is no more black powder pellet in the top grain (like the 24- 54mm motors) and you now get a big fat ignitor to use. They're still pretty reliable - I've only had one ignition failure in my 75mm CTI flights and it was because the ignitor spit out.
Click to expand...
Thanks for the excellent explanation! It sounds like 75mm CTI motors are nearly the same complexity as 38mm Aerotech motors. At least I know what to expect now! Thanks again!
 
CTI and Aerotech are almost identical in assembly for 75 and 98 mm. CTI reloads include the orings required for use in AT hardware so having AT hardware allows use of both manufacturer's reloads in the same case. Many CTI loads are certified in AT cases.
 
BackSeatBryce said:
Thanks for the excellent explanation! It sounds like 75mm CTI motors are nearly the same complexity as 38mm Aerotech motors. At least I know what to expect now! Thanks again!
Click to expand...
One more thing, many of the 75mm motors require grain bonding to the liner. Never seen anything smaller that requires it...
 
cerving said:
One more thing, many of the 75mm motors require grain bonding to the liner. Never seen anything smaller that requires it...
Click to expand...

Aerotech and others normally only require their larger, fast load grains to be bonded.
You can glue them all if you want, not sure of any data that would support doing them all.
But if you do glue them it is a lesser of a chance a casting tube chunk clogging the nozzle and then, BOOM!
 
Rocketjunkie said:
CTI and Aerotech are almost identical in assembly for 75 and 98 mm. CTI reloads include the orings required for use in AT hardware so having AT hardware allows use of both manufacturer's reloads in the same case. Many CTI loads are certified in AT cases.
Click to expand...
Aerotechs 54mm and smaller reloads will have more parts to handle and assemble.
CTI 54's are much simpler for assembly and easier cleanup.
AT & CTI 75mm & 98mm loads are nearly identical.
In my opinion, they are easy to assemble.
 
I like Loki for 75mm. Somewhat similar to CTI 75mm motors when it comes to assembly but you don't have to have the o-ring spacers between the grains. The use of a graphite nozzle is nice as well. Lastly, they're the easiest to use for EX.
 

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