Is the LMS forward closure supposed to have an o-ring in the grove

[SpaceX76]

I am assembling my first LMS motor and noticed that there is a grove in the forward closure that looks likes it's for an o ring. I looked at the diagrams provided with the instructions and it looks like there is an o ring in the grove. However in both of the LMS kits that I purchased there are no o rings that fit that grove.

 

[Tractionengines]

What is/are the exact kits you have? Aerotech has assembly drawings/BOMs of almost everything. We can look up the drawing by item and check for sure.

 

[SpaceX76]

I have 2 Aerotech F23-7FJ/L

 

[Tractionengines]

I can't find info for that one.. but 1/2 way down on this page is a section on the LMS motors. There used to be others, but only 6 still have instructions listed.
http://www.aerotech-rocketry.com/resources.aspx?id=4Maybe those can help give you an idea.

 

[tim cubbedge]

Interesting. I can't find that F23 in LMS anywhere. Only Single use Econojet.

 

[rcktnut]

All the LMS motors assemble basically the same way. Never had any but having an O-ring on the outside of the forward closure assembly would be useless/ not needed although in the instructions the red ring around the bottom most groove looks like an O-ring. The epoxy should seal everything up, and the way the forward closure is assembled if there was an o-ring it would get all "smucked" up with epoxy and would not function like it should anyway. Post your question in the Aerotech thread, but I would say no o-ring needed.

 

[AeroTech]

The ‘F’ LMS were discontinued. The O-ring groove is an artifact of an earlier motor design where we were hoping to reuse the casing several times (“limited use RMS”). When everything worked correctly, we could get three or four firings out of a casing. However, we had occasional problems getting the O-ring to remain in the groove when the forward bulkhead was installed, so the idea was abandoned.

 

[Tractionengines]

AeroTech, THANK YOU for the explanation. It is so nice that you give us more than just a Yes/No answer. It helps us detail oriented types, fill in the blanks, about what we "see" and what we are "told".

Mike.

 

[AeroTech]

AeroTech, THANK YOU for the explanation. It is so nice that you give us more than just a Yes/No answer. It helps us detail oriented types, fill in the blanks, about what we "see" and what we are "told".

Mike.

My pleasure. Feel free to ask anytime.

 

[dpower]

I miss the LMS motors, I like to fly the F27, but usually need a -6 delay, so the LMS F27-8 was great for that, just drill a couple seconds off before assembly.