M3700 in AT 75/7680 Question

[Biodragen]

I have two M3700 reloads. Didn't realize that now it is a 6g liner from what use to be the 5.3 liner which was going to be on loan.

Is there anything besides the M3700 spacer which I assume goes inside the liner that I need to make this work in the 75/7680 case?

 

[rfjustin]

@Cesaroni Technology, see above.

 

[rharshberger]

So the M3700 is a crossload from CTI in a AT case? I am not sure that is even on the certified crossload list/matrix or that a spacer should be used with that combo. Is this intended to be a research motor?

 

[StreuB1]

You need the AT floating forward closure that is used in the 75mm RAS (also available separately).

The floating forward closure goes above the forward seal disc, then the spacer, then the forward nut.

See below AT 75mm RAS picture but instead of the AT spacer, you use the CTI 0.7 grain spacer in its place.

 

[jd2cylman]

No. His problem as I understand it is the liners that came with the motors are 6 grain liner length, not the 5.3 length. The spacers can't go inside the liner. He needs the exact length of the 5.3 liner so he can cut down the 6 grain liner, then use the spacers. At least that's what I'm gathering from all this.

 

[jd2cylman]

This probably should be in the propulsion section. At least there'd be a better chance of @Cesaroni Technology seeing it.

 

[Biodragen]

Problem is resolved.
The M3700 no longer goes into the 5.3 case that was originally designed for it.

I needed another case so decided to go with the AT 75/7680 case and use the M3700 spacer in addition use the AT RAS system just using forward closure and ring from that.

With that I will now have all 75MM cases.

Thanks for the help and input to all who did.

 

[rfjustin]

No. His problem as I understand it is the liners that came with the motors are 6 grain liner length, not the 5.3 length. The spacers can't go inside the liner. He needs the exact length of the 5.3 liner so he can cut down the 6 grain liner, then use the spacers. At least that's what I'm gathering from all this.

I've never seen a 3700 fly in a AT case, I don't think its cross compatible, but I certainly could be mistaken. OP needs either the CTI 5.3 case, or the 6 grain case to make this work. To your point, liner correct liner length needs to be known though.

Good luck OP.

 

[rfjustin]

Problem is resolved.
The M3700 no longer goes into the 5.3 case that was originally designed for it.

I needed another case so decided to go with the AT 75/7680 case and use the M3700 spacer in addition use the AT RAS system just using forward closure and ring from that.

With that I will now have all 75MM cases.

Thanks for the help and input to all who did.

Thanks for the feedback!

 

[Biodragen]

Thanks for the feedback!

 

[rfjustin]

Awesome! Looking forward to seeing it fly!

 

[Syclone]

No. His problem as I understand it is the liners that came with the motors are 6 grain liner length, not the 5.3 length. The spacers can't go inside the liner. He needs the exact length of the 5.3 liner so he can cut down the 6 grain liner, then use the spacers. At least that's what I'm gathering from all this.

Almost sounds like the wrong liner was packaged. I flew one last year and it needed the 0.7 grain spacer to fit the 6g case.

 

[jd2cylman]

Almost sounds like the wrong liner was packaged. I flew one last year and it needed the 0.7 grain spacer to fit the 6g case.

To be honest, I was just on the phone, so I never saw any parts. But he’s all set now, so it’ll be cool.

 

[mikec]

This is a very confusing situation. Certainly the label on the M3700 reload says nothing about needing a non-standard spacer, does it? Nor do the online instructions or the product notes. I'm glad you figured it out somehow.

 

[WILDMANRS]

Bring it with you tomorrow

 

[3stoogesrocketry]

I'm 99.99 percent sure I saw somewhere the 5.3 case is being stopped and the liner grain stack fitted for 6 grain cases. I nay be wrong.

 

[Biodragen]

Bring it with you tomorrow

I will