Using CTI 75mm motor spacers question.

[Dave A]

2 spacers max in a standard case. I'm sure somewhere in the archives of this site, Jeroen from CTI states 2 spacers used is fine. This was a pretty popular question when they first came out with the spacers. I have flown an L1115 in the 6 grain case with no issues. That being said I wouldn't recommend it for the simple reason of doing so makes motor assembly quite the chore. 75mm grains are about 5" long. With 2 spacers that puts the forward closure, insulator and o rings 10" down. Don't know about you but I don't have 10" fingers. It was difficult to build up the forward end of the motor and not have something shift out of place.
Also just thought I would point out that the 75mm 6gxl case should be labeled a 7G. It is a full grain longer than the 6G.
Yes, the spacers are in front of the closure then the ring holds them in.
It's been 8 years since I flew it so I can't help with the last question.

CORRECTION:
No chore at all.
1) Insert the nozzle into the case (with nozzle carrier installed)
Insert all the grains into the case and o-rings (as specified), seal disk or washer.
I check to see if the last grain spacer is needed and check that gap per instructions.
2) Stand the case upright with nozzle down.You can rest the nozzle carrier on top of 1 spacer.
CTI says spraying the inside of the case with silicone is good idea so none of the o-rings try to roll or flip.
3) Then I push the case down over the assembly just far enough for the rear retaining ring to be installed later.
4) Insert the completed fwd closure assembly with tracking smoke on the fwd end and push it in with the 1st spacer. Then push in the 2nd spacer. I have an extra spacer I use the push that last one deep enough to install the fwd retaining ring flush.
5) Then complete by installing the rear retaining ring per the CTI instructions.
No 10 inch fingers needed.

NOTE: I changed my steps, CTI says it is not good to slide the fwd closure from one end of the case to the other. The o-ring might roll or pinch.

 

[Rocketjunkie]

The 98-6GXL case is 9" longer than the 6G (45" propellant vs 36") So The 6GXL to 6G spacer must be 9" long, the rest would be 6".